NOTIZIARIO Neutroni e Luce di Sincrotrone - Issue 11 n.2, 2006

Rivista del Consiglio Nazionale delle Ricerche

NOTIZIARIO Neutroni e Luce di Sincrotrone

ISSN 1592-7822

Vol. 11 n. 2

July 2006 - Aut. Trib. Roma n. 124/96 del 22-03-96 - Sped. Abb. Post. 70% Filiale di Roma - C.N.R. p.le A. Moro 7, 00185 Roma

www.cnr.it/neutronielucedisincrotrone

NOTIZIARIO Neutroni e Luce di Sincrotrone

Rivista del Consiglio Nazionale delle Ricerche Cover photo: Laboratory scientists, engineers, instrument scientists and others at the first neutrons produced on Friday, April 29, 2006 at the Spallation Neutron Source.

SUMMARY EDITORIAL NEWS SNS Up and Spalling .............................................................. 2 A. Womac

SCIENTIFIC REVIEWS Hydrogen vibrational dynamics in ionic metal hydrides revealed through inelastic neutron scattering ..................................................................................... 4 D. Colognesi, M. Zoppi

NOTIZIARIO Neutroni e Luce di Sincrotrone published by CNR in collaboration with the Faculty of Sciences and the Physics Department of the University of Rome “Tor Vergata”.

Vol. 11 n. 2 Luglio 2006 Autorizzazione del Tribunale di Roma n. 124/96 del 22-03-96 EDITOR:

C. Andreani

Neutron-resonance capture as a tool to analyse the internal compositions of objects non-destructively .... 14 H. Postma, P. Schillebeeckx

RESEARCH INFRASTRUCTURES GELINA, a neutron time-of-flight facility for high-resolution neutron data measurements................ 19 W. Mondelaers, P. Schillebeeckx

M & N & SR NEWS

EXECUTIVE EDITORS:

Lightsources.org enters its second year of operation .... 26

M. Apice, P. Bosi, D. Catena

M. Bertolo

EDITORIAL OFFICE:

Reactor Institute Delft and the R3 department The academic Dutch neutron facility................................. 26

L. Avaldi, S. Imberti G. Paolucci, R. Triolo, M. Zoppi EDITORIAL SERVICE AND ADVERTISING FOR EUROPE AND USA:

P. Casella

M. Blaauw

ILL Next standard proposal round .................................. 28 G. Cicognani

CORRESPONDENTS AND FACILITIES:

J. Bellingham (NMI3) M. Bertolo (I3-IA-SFS) A.E. Ekkebus (SNS) ON LINE VERSION

V. Buttaro CONTRIBUTORS TO THIS ISSUE:

M. Bertolo, M. Blaauw, G. Cicognani, D. Colognesi, A.E. Ekkebus, M. Helm, P. Michel, W. Mondelaers, H. Postma, P. Schillebeeckx, J. Tomkinson GRAPHIC AND PRINTING:

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AP.G.RA.D(E), Application of γ-ray diffraction (October - November 2006) ........................... 29 G. Cicognani

Jefferson Lab’s CEBAF Continues Experiments While Gearing Up for an Increase in Energy ............................ 30 A.E. Ekkebus

Spallation Neutron Source - Progress February 2006 ... 32 A.E. Ekkebus

FELBE: a new infrared free-electron-laser user facility ......................................................................................... 33 M. Helm, P. Michel

NEWS AND MEETING REPORTS .............................................................36 CALL FOR PROPOSAL ........................................................................... 39 CALENDAR ............................................................................................... 40 FACILITIES ............................................................................................... 43 Vol. 11 n. 2 July 2006

EDITORIAL NEWS

SNS Up and Spalling After seven years of construction, the Spallation

beam with a time averaged proton power on target

Neutron Source (SNS) at Oak Ridge National Lab-

of 185 watts. Four detector tubes counted for 822

oratory (ORNL) in Oak Ridge, Tenn., is successful-

seconds. The accompanying chart displays the

ly producing neutrons. At 2:04 p.m. EDT, April 28,

118k neutrons counted. The neutron diffraction

2006, scientists at SNS watched, anticipating suc-

peaks are clearly visible.

cess, as protons hit right on the target, spalling

The SNS project is a unique partnership among

neutrons and marking a major milestone for the

six Department of Energy (DOE) National Labo-

$1.4 billion research facility. Within 88 minutes of

ratories, making SNS the first facility designed

13

the first beam on target, a pulse of 10 protons was

and built through a precedent-setting collabora-

delivered to the target completing proton and neu-

tion. Lawrence Berkeley National Laboratory was

tron flux criteria for project completion.

responsible for the front-end system that gener-

On May 20, the first of the SNS instruments, the

ates the proton beam; Los Alamos National Labo-

Backscattering Spectrometer, opened the primary

ratory and Thomas Jefferson National Accelerator

shutter and counted neutrons.

Facility designed and built the room-temperature

Another milestone was met at the same time: these

and superconducting sections of the linac;

neutrons were the first “cold neutrons” produced

Brookhaven National Laboratory designed the

at SNS from the cryogenic moderator system.

proton accumulator ring; ORNL designed and

Success continued on May 23 when the Backscat-

built the target station; and Argonne National

tering Spectrometer became the first instrument to

Laboratory was responsible for hosting the initial

record time-of-flight data. The 25g sample of fluo-

instrument development.

rinated mica was placed in a 3 cm by 3 cm neutron

“To arrive at this point, on budget, on scope, and

Figure 1. Fluorinated mica produced these neutron diffraction peaks at SNS.

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on schedule is a tribute to the six national labs

European Community’s Integrated Infrastructure

working together. I think this is an exceptional ac-

Initiative for Neutron Scattering and Muon Spec-

complishment,” said Jeff Wadsworth, ORNL di-

troscopy (NMI3), Oak Ridge Associated Universi-

rector.

ties, and the Joint Institute for Neutron sciences.

With the construction phase now over and the

For more information, visit the website at

commissioning phase beginning, SNS will soon

www.sns.gov/workshops/ian2006. For more in-

have three instruments, the Backscattering Spec-

formation on SNS, its operations or related work-

trometer and the Liquids and Magnetism Reflec-

shops, visit our website www.sns.gov.

tometers, operational for initial users. Initial users will submit research proposals, which will be peer-

Amanda Womac

reviewed and recommended based on scientific

ORNL

and technological impact, as well as experience of the experiment team. By fall 2006, SNS expects initial users to be selected for these first three instruments. Future operational timelines at SNS include the following: • Summer 2007: Power level exceeds 100kW • Fall 2007: General User Program for first three instruments • Winter 2008: 1MW capability with 7 instruments in General User Program Continuing the outreach efforts for ORNL’s major neutron scattering facilities, we are hosting an in-

SNS CHRONOLOGY December 1999 – Groundbreaking ceremony November 2002 – Front-end commissioning begins April 2003 – Linac and target equipment installation begins August 2003 – Ring equipment installation begins March 2004 – Instrument installation begins June 2004 – Project staff moves to construction site

ternational “Imaging and Neutrons 2006” confer-

January 2005 – Warm linac commissioning completed

ence, October 23-25th, which will give researchers

May 2005 – First target module delivered

an opportunity to create a multi-disciplinary re-

June 2005 – Construction hours without a lost workday reaches 4 million

search network for applications of neutron imaging; identify needs and potential contributions of imaging with neutrons; recognize possible new imaging techniques; and produce a report identifying possible neutron research directions for the international science community.

The multi-disciplinary conference incorporates a variety of applications, including the medical/ biomedical community; chemistry, engineering, geology, and physics; energy and nuclear power; material research; cultural heritage; and homeland security.

September 2005 – Commissioning of entire linac completed December 2005 – Mercury loaded into target system January 2006 – Beam accumulated in ring and extracted to dump; successful testing of mercury loop April 2006 – First beam on target: Critical Decision for performance test accomplished May 2006 – First instrument, the Backscattering Spectrometer, opened primary shutter and counted the first “cold neutrons” produced from the cryogenic moderator system

The workshop is being sponsored by ORNL, the

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Hydrogen vibrational dynamics in ionic metal hydrides revealed through inelastic neutron scattering D. Colognesi and M. Zoppi Consiglio Nazionale delle Ricerche Istituto dei Sistemi Complessi: Sezione di Firenze

Via Madonna del Piano 10 50019 Sesto Fiorentino (FI), Italy

Abstract Inelastic neutron scattering spectra from polycrystalline alkali (Li, Na, Rb and Cs) and heavy alkaline-earth (Ca, Sr and Ba) hydrides, measured on TOSCA-II spectrometer at low temperature in the energy transfer range 3 meV<E<500 meV, are reported. From the medium-energy regions, coinciding with the optical phonon bands, accurate generalized self inelastic structure factors and (if possible) hydrogen-projected densities of phonon states are extracted and compared to ab-initio lattice dynamics results. The overall agreement is found satisfactory. In addition, in CaH2, simulations provide a compelling support to a recent physical interpretation of the recorded spectral features and allow to separate the contributions produced by the two non-equivalent hydrogen atoms. In conclusion, incoherent inelastic neutron spectroscopy proves to be a stringent validation tool for lattice dynamics simulations of H-containing materials.

Keywords: Metal hydrides; Inelastic neutron scattering; Lattice dynamics

unit, which makes it the simplest ionic crystal in terms of electronic structure. Because of these peculiar physical properties, LiH lattice is well described, both structurally [6] and dynamically [7-9]. However, as far as NaH, KH, RbH and CsH are concerned, besides incomplete experimental studies on NaH vibrational spectra [9], only lattice dynamics calculation has been reported in Ref. [10] before our investigations. Given this scanty scenario, a detailed experimental study on the whole series of alkali metal hydrides was planned [11,12] in order to provide the first high-quality spectroscopic measurements on all the AlkH. We have proved that the combined use of Incoherent Inelastic Neutron Scattering (IINS), from which the Hydrogen-projected Density of Phonon States (H-DoPS) can be worked out, and of ab-initio simulations, from which important physical quantities can be derived (lattice constants, bulk modulus, phonon dispersion curves, density of phonon states etc.) can provide a deep insight into the problem of the hydrogen dynamics in condensed matter.

On the other hand, differently from AlkH, which exhibit the same ambient-pressure structure moving from Li to Cs, alkaline earth hydrides are characterized by three distinct subsets: BeH2, unstable and body-centered orthorhombic with an Ibam space group [13], MgH2, well described and showing a rutile-type structure (tetragonal, P42/mnm) a low pressure [14], and, finally, Ca, Sr and Ba dihydrides, isomorphic and crystallizing with an orthorhombic lattice (at low pressure and temperatures below 600 oC), exhibiting the Pnma space group. These three Heavy Alkaline-Earth Hydrides (labeled HAEH2 in short) were structurally studied for the first time in 1935 [15], when the metal atom position was determined through standard x-ray powder diffraction: alkaline earth atoms appeared arranged in a slightly-distorted hexagonal close-packed structure. On the other hand, the hydrogen locations were not properly resolved.

However further neutron scattering experiments on deuterated powder samples (CaD2 [16], SrD2 [17] and BaD2 [18]) showed a slightly distorted PbCl2-type structure for all the three HAEH2. Finally, recent x-ray singlecrystal measurements on CaD2 and SrD2 [19], and on BaH 2 [20] basically confirmed the neutron scattering findings with few minor differences.

Introduction Ionic hydrides have gained a new wave of interest in the last ten years, mainly in connection with the hydrogen storage problem, where, for example, alkali and alkalineearth borohydrides and aluminohydrides seem to play a relevant role [1]. The simplest ionic hydrides can be formed by H through reaction with an alkali metal [2].

The first x-ray diffraction studies [3] showed that LiH, NaH, KH, RbH and CsH (AlkH for short) crystallize with the rock-salt structure at ambient pressure. In these materials hydrogen is present in the form of anion: electron distribution investigations [4] estimated the H ionic effective charge in AlkH to fall in the range between 0.93 and -1.11 electron charges, indicating that alkali metal hydrides are probably similar to the respective halides as regards the electronic structure. In view of this feature, which gives rise to long-range interactions between hydrogen atoms, the H dynamics in these compounds is expected to be very different from that in transition-metal hydrides. Nevertheless, virtually only LiH has been extensively studied [5], both theoretically and experimentally, since it exhibits a straightforward rocksalt structure having only four electrons per asymmetric

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If the situation concerning the microscopic structure of HAEH2 could be considered as quite satisfactory, this was not at all the case about their lattice dynamics, where only two experimental studies had been so far reported, both making use of the IINS technique in order to extract the hydrogen vibrational spectra. However, while one work [21] showed good quality data from CaH2 at temperatures of 10 K and 295 K, the other, which had the ambition to explore the complete series of HAEH2 [22], offered only low-resolution spectra in a narrow energy transfer range (50-155 meV), due to the limitations of the neutron equipment of that time. For this reason we have reported new incoherent inelastic measurements on all the HAEH2 using a modern neutron spectrometer, which exhibits both good energy resolution and wide energy transfer range [23].

Finally, if one considers the first-principles simulations of the HAEH 2 properties, the present scenario also looked rather unsatisfactory. Only two groups have devoted some effort to this class of compounds: El-Gridani and coworkers have simulated the elastic, electronic and structural properties of CaH2 [24,25], SrH2 [26] and BaH2 [27] making use of the Hartree-Fock or the pseudo-potential method in connection with the CRYSTAL95 program, while Smithson et al. [28] studied the stability and electronic structure of all the metal hydrides (including of course HAEH2) through the VASP simulation package. However, no information on the lattice dynamics was reported by either groups. This insufficient situation prompted us to develop independent ab-initio lattice dynamics simulations in order to check the residual structural ambiguities of HAEH2 and, moreover, to extract phonon spectra to be compared with the experimental neutron results [23].

The rest of the article will be organized as follows: experimental IINS procedure will be dealt with in Sect. 2, and spectral data analysis will be shortly described in Sect. 3, while Sect. 4 will be devoted to a brief explanation of the ab-initio simulations. In Sect. 5 we will discuss the experimental results in comparison with the simulation ones. Finally, Sect. 6 will contain the conclusions of the present study.

Experimental procedure The IINS measurements were carried out using the TOSCA-II inelastic spectrometer of the ISIS pulsed neutron source at Rutherford Appleton Laboratory, Chilton, Didcot (UK). TOSCA-II is a crystal-analyzer inversegeometry spectrometer [29], where the final neutron energy, E 1 , is selected through two sets of pyrolytic graphite crystal analyzers placed in forward-scattering (at around 42.6° with respect to the incident beam) and in back-scattering (at about 137.7°).

This arrangement fixes the nominal scattered neutron

energy to E 1 =3.35 meV (forward-scattering) and to E1=3.32 meV (back-scattering). Higher-order Bragg reflections are filtered out by 120 mm-thick beryllium blocks cooled down to a temperature lower than 30 K. The incident neutron beam, on the other hand, spans a broad energy range allowing coverage of an extended energy transfer, E, region: 3 meV<E<500 meV. Because of the fixed geometry of this spectrometer, the wave-vector transfer, Q, is related to the energy transfer through a monotonic function, roughly proportional to the square root of the incoming neutron energy, E0: Q=Q(E0)∝√E0.

TOSCA-II has an excellent energy resolution in the accessible energy transfer range (∆E/E0≅1.5–3%).

The sample cells used for LiH, NaH, CaH2, SrH2 and BaH 2 were made of aluminum with a slab geometry (size: 34×48 mm2, with 1 mm-thick walls and 5 mm of internal gap). Special care was devoted to preventing possible hydroxide formation during the sample loading procedure. The measurements on KH, RbH and CsH required, in contrast, a different choice of the sample container, due to the very unstable and sensitive nature of these three hydrides. After their syntheses they were accurately sealed in square quartz cells (40 x 40 mm2, 7.5 mm thick).

In Tab. I we have summarized various experimental details concerning the metal hydrides, all in the form of polycrystalline powder as checked by means of standard x-ray diffraction. Before the actual measurements, the two empty cells were cooled down to the low temperature of the experiment, and their Time-of-Flight (ToF) spectra recorded up to an Integrated Proton Current (IPC) of 344.1 and 3451.4 µA h for the aluminum and the quartz container, respectively.

Then the hydride samples were placed in the cryostat at T=20 K (except SrH2, measured at T=16 K) for the IINS measurements. Raw IINS spectra for all the AlKH and HAEH2 are reported in Fig. 1, while further experimental details can be found in Refs. [11,12,23].

sample LiH NaH KH RbH CsH CaH2 SrH2 BaH2

T(K) 20.1(1) 20.1(1) 20.0(1) 20.0(1) 20.0(1) 20.0(3) 16.0(3) 20.0(3)

µAh) mass(g) p(%) purity(wt.)

IPC(µ 2101.0 660.5 3284.0 3213.9 3124.9 1828.9 3248.1 2551.9

1.4 3.1 2.6 5.9 9.2 3.9 6.1 6.4

15.96 13.21 6.02 7.53 3.32 16.98 12.65 8.12

97% 95% >97% >97% >95% 98% 99.5% 99.5%

Tab. I. Sample description, including experimental temperature T, integrated proton current IPC, mass, sample scattering power p (at E0=103.3 meV), and purity.

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Data analysis The experimental back-scattering ToF spectra were transformed into energy transfer data, detector by detector, making use of the standard TOSCA-II routines available on the spectrometer. Spectra were added together in a single data block (disregarding forward-scattering data because of their larger instrumental background).

This grouping procedure was justified by the narrow angular range spanned by detectors, since the corresponding full-width-at-half-maximum, x, was estimated to be only 8.32° [29]. In this way we produced double-differential cross-section measurements along the TOSCA-II kinematic path (Q(E), E) of the (hydride sample + can) systems, plus, of course, the empty cans. Data were then corrected for the k1/k0 kinematic factor (see Fig. 1), and the empty-can contribution was properly subtracted [30], taking into account the E0-dependent sample transmission as explained below.

At this stage the important corrections for self-absorption attenuation (especially relevant for LiH and CsH, since σabs(Li)=70.5·10-28 m2 and σabs(Cs)=29.0·10-28 m2 at E0=25.8 meV [31]) and multiple scattering contamination were performed through the analytical approach suggested by Agrawal and Sears in the case of a flat slab-like sample

[32]. However this method needed two important inputs, which are related to the microscopic dynamics of the measured sample, namely: (a) the hydride total scattering cross-section σt(E0), known to be largely dependent on E0 because of H; (b) an estimate of the hydride scattering law to be folded with itself in order to generate multiple scattering contributions. Needless to say the determination of this scattering law is actually the main aim of the present work. Both procedures (i.e. self absorption and multiple scattering corrections) were accomplished in the framework of the incoherent approximation [33]. This was totally justified by the preponderance of scattering from the H nuclei and by the polycrystalline nature of the samples. The hydride total scattering cross-section, σ t(E0), was estimated summing the small metal contribution (i.e. bound cross-section, constant in E0) to the large and E0-dependent H part. The latter was evaluated from the approximate H-DoPS, ZH(E), reported in Refs. [8,10,21,22], making use of Eqs. (3), (11) and (12) of Ref. [34]. A test of the σt(E0) sensitivity to the details of the phonon frequency distributions was also performed on LiH and CaH 2, since a more accurate ZH(E) were available in these cases [8,21].

Only minor differences were detected, showing that in these compounds σt(E0) is only weakly influenced by the particulars of ZH(E). A more delicate issue was the choice of the model self scattering laws, S s(n)(Q,E), (with n standing for metal or proton) to be used for the multiple scattering estimate, since the approach followed for σt(E0) was regarded as too coarse, at least for the NaHCsH series, and for SrH2 and BaH2, where no reasonably accurate ZH(E) was accessible. In addition, it has to be noted that Eqs. (11) and (12) of Ref. [34] are not strictly rigorous in the case of alkaline earth hydrides, since

Figure 1. Raw neutron spectra from alkali metal hydrides (a), and heavy alkaline-earth hydrides (b) measured in backscattering on TOSCA-II at T<_ 20 K. Spectra have been vertically shifted and normalized to similar peak height for graphic reasons.

Figure 2. Evaluation of the double-inelastic-scattering (red dotted curve) for NaH at T=20 K, together with the TOSCA-II experimental data (blue circles with error bars). The estimate of the sample-dependent background has also been reported (green dashed line).

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their crystal structure is not exactly cubic (isotropic) and, moreover, two non-equivalent H sites (H1 and H2 [16-20] ) exist in the lattice, and then two distinct Ss(H)(Q,E) functions should be employed for estimating multiple scattering; a requirement that was obviously thoroughly impossible at this stage.

Thus, retaining the aforementioned approximation of Ref. [34], two model DoPS (i.e. ZH(E) and ZMet(E)) were set up for each hydride sample, using all the pieces of information available from the present uncorrected neutron spectra, from Refs. [10,22], and also from the ab-initio simulations of Sect. 4, and then combining them together through the existing physical constraints as explained in detail in Ref. [35]. Multiple scattering contributions were found to be modest, but not at all negligible, in the energy transfer interval of interest (i.e. 50 meV<E<150 meV) containing the optical single-phonon scattering bands (also known as “fundamental”). However, as already verified in various other cases [36], a relevant multiple scattering term on crystal-analyzer inverse-geometry spectrometers is composed of one inelastic scattering event together with one (or more) elastic scattering events. This term appeared almost indistinguishable from the single (inelastic) scattering and then it was not subtracted from the experimental neutron spectra. On the contrary, multiple scattering contributions containing two (or more) inelastic scattering events were carefully evaluated, ranging between 3.0% (KH) and 10.5% (CaH2) of the total neutron counts in backscattering in the E-interval of interest. Finally, these estimates were removed from the processed neutron spectra (see Fig. 2), which were finally transformed into generalized self inelastic structure factors, Σ(Q,E):

Σ (Q, E) = ∑ cn σ n S s(n) (Q, E),

tracted from the contaminated calcium dihydride spectrum. As for the other hydrides, no sign of hydroxide contamination was detected in the low-energy zone.

In the case of AlkH, exhibiting an isotropic structure with only one single H site, the extraction of the H-DoPS was attempted. The last procedure before this operation was the evaluation and subtraction of the tiny metal scattering and of the more conspicuous multiphonon contribution, containing both optical-plus-acoustic combinations and optical-plus-optical overtones. The multiphonon contribution was not completely negligible because of the relatively high Q-values attained by

(1)

n

where cn is the concentration of the nth non-equivalent atomic species, and σn its total scattering cross-section (bound).

By inspecting the Σ(Q,E) spectrum from CaH2 in Fig. 3, some clear Ca(OH)2 contaminations have been detected, similarly to what was observed in Ref. [21], despite the care used in the cell loading process (see Sect. 2 for details), being some hydroxide probably already present in the commercial hydride samples.

These unwanted features were removed making use of a previous IINS measurement on Ca(OH)2 [37], operated on a similar spectrometer (namely TFXA, i.e. TOSCA’s precursor): calcium hydroxide data were processed in the same way as CaH2 and, after a proper scaling, sub-

Figure 3. Generalized self inelastic structure factor from CaH2 (a), SrH2 _ 20 K. (b), and BaH2 (c), recorded in back-scattering at T<

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TOSCA-II in the 50 meV<E<150 meV experimental range, namely 6.1 Å-1<Q<9.6 Å-1 (in back-scattering). After removing the practically negligible metal contribution to Σ(Q,E), processed AlkH data were proportional to the self inelastic structure factor [14] for the H ions, Ss(H)(Q,E). Due to the isotropic nature of the AlkH crystals, such a quantity could be easily interpreted as the sum of spherically averaged n-phonon terms (n=0, 1, 2...), each describing a neutron scattering process of creation or annihilation of n vibrational quanta in the crystal lattice. As far as the H-DoPS is concerned, the only useful contribution of the experimental spectrum is the one-phonon component of Ss(H)(Q,E), namely Ss,+1(H)(Q,E).

The following equation shows its relation with the Hprojected density of phonon states:

(2)

where MH is the proton mass, kB is the Boltzmann constant and 2WH(Q) is the well-known Debye–Waller factor, related to the mean square displacement of H (and to the H-DoPS itself) via:

(3)

The full expansion of Ss(H)(Q,E) in terms of phonon operators was employed in combination with the simulated H-projected DoPS to evaluate the multiphonon scattering. Its contribution in the optical-band energy range (50–150 meV) is shown for NaH in Fig. 4. Thus experimental Ss(H)(Q,E) spectra were analyzed through an iterasample

〈u2〉H (Å2)

〈T〉〉H (meV)

Ω0,H (meV)

LiH

0.062(1)

80(1)

109.2(9)

NaH

0.0736(4)

66.9(4)

90.7(5)

KH

0.0856(5)

57.7(4)

78.2(6)

RbH

0.0893(4)

55.0(2)

74.4(4)

CsH

0.0953(3)

51.3(2)

69.5(3)

Tab. II. Mean square displacements 〈u2〉H, mean kinetic energies 〈T〉H, and Einstein frequencies Ω0,H of hydrogen in alkali metal hydrides at T=20 K from the present inelastic neutron scattering measurements.

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Figure 4. Evaluation of the multiphonon contributions (red dashed curve) for NaH at T=20 K, together with the TOSCA-II single-scattering experimental data (blue circles with error bars).

tive procedure [34,35], aiming to simultaneously extract ZH(E) and 2WH(Q) by means of Eqs. (2) and (3). Technicalities can be found in Refs. [11,12,35], while the experimental ZH(E) determinations obtained are reported in Figs. 5 and 6. From these ZH(E) data, making use of normal and Bose-corrected moment sum rules [39], we were also able to derive three important physical quantities related to the hydrogen dynamics in these hydrides, namely: the H mean square displacement 〈u2〉H, the H mean kinetic energy 〈T〉H, and the H Einstein frequency Ω0,H, all reported in Tab. II. First-principle simulation The vibrational dynamics of the aforementioned ionic hydrides (except LiH) has been simulated through a totally ab-initio method based on the density functional theory and making use of pseudo-potentials and a plane-wave basis. Calculations were carried out using the plane-wave density functional theory as implemented in the ABINIT code [40]. Here, two main limitations occur. The first is the use of pseudo-potentials to represent the core electrons, allowing us only to include relativistic effects in an essentially non-relativistic code. This choice is of the maximum importance for reducing the number of plane waves representing the electronic wave-function to a level that is tractable with the currently available computer power. The second limitation concerns the use of the density functional theory, where two general approaches apply: in the Local Density Approximation (LDA) the exchange and correlation energies are described as functions of the local electron density at each point, while in the Generalized Gradient Approximation (GGA), electron density gradients are also taken into account. It has been shown that the GGA provides results in better agreement with experimental data than those obtained from the LDA when low-Z elements are

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Figure 6. Comparison between experimental and simulated optical branches of the hydrogen-projected density of phonon states in heavy alkali hydrides: neutron scattering experimental results (red circles with error bars) and ab-initio simulations (blue curves).

involved. However, the opposite is found if high-Z elements are considered. On the other hand, Bellaiche et al.

[41] have calculated the equation of state for LiH and LiD using Hartree–Fock theory and two different LDA functionals, considering both the pseudo-potential and

Figure 5. Hydrogen-projected density of phonon states in LiH. The experimentally-determined result is plotted as magenta circles, the red histogram represents a DDM13-potential lattice dynamics simulation [10], the blue line a SM7-potential lattice dynamics simulation [8], and the green line the old neutron measurement [8]. See main text for details.

the all-electron approaches. Results from Hartree–Fock and LDA approaches differ less than 1%, indicating that, at least for this system, the equation of state depends only very weakly on the electron correlation. Because, in principle, for the solid state, neither LDA nor GGA have clearly proved their superiority, it was decided to carry out the AlkH simulations considering the LDA (less demanding as regards computer time), using the Teter–Padé parametrization [42] and the norm-conserving Troullier–Martins pseudo-potentials [43]. Some exceptions were represented by K, Ca, Sr and Ba ions, where the Hartwigsen–Goedecker–Hutter pseudo-potentials had to be employed [44]. As for the HAEH2 series the Generalized Gradient Approximation (GGA) has been preferred, using the parameterization introduced

by Perdew, Burke and Ernzerhof [45]. The reasons for this choice can be found in Refs. [12,46], where it is shown that standard energy minimization methods using GGA give an adequate lattice geometry although the computationally-prohibitive thermal and zero point effects are not included. In addition, as the (n-1)s and (n-1)p electrons are known to be important for the alkaline earth elements, semi-core electrons were explicitly considered in the appropriate pseudo-potentials.

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It was carefully verified for all simulations that full convergence was achieved as regards both the number of kpoints in the reciprocal space and the energy cut-off of the plane waves. So, the final choice in the hydride calculations was a mesh of 8x8x8 points for AlkH (and 4x4x4 for HAEH2) in the reciprocal space, and a cut-off of 1360.72 eV. In order to calculate well-defined densities of phonon states, phonons were determined on a 16x16x16 grid of points in the first Brillouin zone. However a full electronic calculation on such a grid was not necessary, since an accurate interpolation procedure through the ANADDB [47] program was used. ABINIT results for ZH(E) for heavy AlkH are plotted in Fig. 6, while further details on the simulation work on these metal hydrides can be found in Ref. [46]. Finally, the actual IINS spectra for HAEH2 were generated using the ACLIMAX code [38], which takes exactly into accounts thermal and powder-average effects, together with over-

Figure 7. Comparison between the generalized self inelastic structure factors derived from the neutron scattering experiments (blue line histograms), and from the ab-initio simulations (dashed red lines) for heavy alkaline earth hydrides. The one-phonon fundamental components of the latter spectra have been also reported (as dotted green lines) to mark the end of the phonon density of states.

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tones and combinations up to the tenth quantum event.

Simulated generalized self inelastic structure factors are reported in Fig. 7 (together with their respective fundamental components).

Discussion A comparison among the various determinations (both experimental and simulated) of the H-DoPS for LiH could be finally established at this stage. In Fig. 5, four H-DoPS estimates have been plotted together in the frequency region concerning the two optical bands, namely the Translational Optical (TO) and the Longitudinal Optical (LO), which actually contain more than 97% of the total ZH(E) area [10]. The present IINS experimental result [11] is plotted as magenta circles, the red histogram represents the DDM13-potential lattice dynamics simulation [10], the dotted blue line is the SM7-potential lattice dynamics simulation from Verble et al. [8], and the dashed green line stands for the old IINS measurement from Zemlianov et al. [8]. As a preliminary comment, one can easily observe the existence of a fair general agreement among all the four ZH(E) in the TO range, at least as far as the peak position is concerned. On the contrary, the LO region looks much more uncertain, the peak center varying from 115 meV up to 140 meV. The reason for such a behavior is easily understandable for SM7 and DDM13 data: these lattice dynamics calculations made use of the some parameters (7 and 13, respectively) derived from a fit of the same LiD dispersion curves measured by Verble et al. [8] (for a detailed comparative discussion on the differences between the SM7 and DDM13 H-DoPS calculations see Ref. [10]). By a simple inspection of these experimental dispersion curves, it is clear that the LO neutron groups are really few (four values plus one infra-red measurement at the Î&#x201C; point). However the disagreement between the present IINS ZH(E) and the old one is difficult to explain, so that we are inclined to think that these discrepancies are due to experimental imperfections in the data analysis of the latter (e.g. multiple scattering or multiphonon scattering subtraction).

Selecting the two most recent experimental and simulated ZH(E), namely the present IINS and the DDM13 estimates, we can observe an overall semi-quantitative agreement, the main discrepancies being concentrated in two regions: at low energy, in the onset of TO band (65 meV<E<90 meV), and in the LO band as a whole (112 meV<E<145 meV). As for the latter, a simple energy shift of 4.5 meV seems sufficient to largely reconcile IINS and DDM13, while in the former case, neutron data appear somehow broader than lattice dynamical ones (the IINS width being about 5.1 meV wider than the DDM13 one).

Considering the TOSCA-II energy resolution in this region (1.6 meV), a simple explanation based only on experimental effects can be easily discarded. However such a broad-

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ening of the H-DoPS TO bands might be the mark of the hydrogen anharmonic dynamics in LiH through a finite phonon life-time [11]. As for heavier alkaline metal hydrides (i.e. the NaH-CsH series), our experimental determinations of the H-projected densities of phonon states (see Fig. 6) contained detailed information on the hydrogen self-dynamics in such compounds, especially as regards its dependence on the cation atomic number and the lattice constant. As we have already mentioned in Sect. 1, there is no previous experimental study available on ZH(E) in these systems (except a preliminary report on NaH [9]); thus the present work fills a large gap in the understanding of the H vibrational dynamics in alkali metal hydrides. In Fig. 6 a detailed comparison between IINS and ABINIT H-DoPS curves is shown: one observes a satisfactorily good agreement in the case of KH, RbH and CsH. As for NaH, the comparison between experiment and simulation is globally acceptable, but not so good as for the other hydrides. For example, the position of the first ZH(E) peak (due to the TO phonon band) is not precisely reproduced by ABINIT. A clearly remarkable feature is represented by the strong similarity of the H-projected densities of phonon states in the last three AlkH: it suggests that KH, RbH and CsH could be gathered together in a sub-group of compounds rather different from LiH [8,10], NaH being a sort of ‘crossover’ alkali metal hydride. The effect of the experimental energy resolution has been checked and found irrelevant in the present spectral range (50 meV<E<150 meV). Together with the phonon energy calculations, ABINIT code has also provided reliable estimates of the AlkH lattice constants (see [46]), whose discrepancies from the experimental values [13] are always lower than 1%. Another interesting characteristic of the ABINIT data is the lowering of both transverse and longitudinal optical branches while the cation atomic number increases. This fact is very evident from the H-DoPS plotted in Fig. 6. In addition, one can observe the behavior of the transverse optical branches, which become globally sharper moving from NaH to CsH. However, some dispersion in E is still present and clearly visible and this can be interpreted as the effect of a residual long-range interaction between H ions. Our experimental determinations of the generalized self inelastic structure factor in orthorhombic alkaline earth hydrides (see Figs. 3 and 7) contain detailed information on the hydrogen self-dynamics in these compounds, even though in a less direct form than in H-DoPS. As we have already mentioned in Sect. 1, there was no previous high-resolution experimental study available on Σ(Q,E) in two of these systems (namely SrH2 and BaH2); thus the present measurements [23] fill a certain gap in the knowledge of the H vibrational dynamics in ionic hydrides. As for CaH2, the present estimate of Σ(Q,E) shows an excellent agreement

with the recent one from Morris et al. [21], providing a further improvement of the spectral energy resolution.

Looking at Fig. 3 one can immediately distinguish three main spectral areas for all the HAEH2 patterns reported, if the small acoustic part at low energies (E<50 meV) is disregarded. Choosing, for example, SrH2 as reference, one observes a three-peak zone from 67 meV to 95 meV (labeled “A”), then a second three-peak zone from 101 meV to 136 meV (labeled “B”), and finally a large hump at E>137 meV (labeled “C”). Actually a remarkable feature is represented by the strong similarity among the three generalized self inelastic structure factors of HAEH2: it suggests that even from the dynamical point of view CaH2, SrH2 and BaH2 can be gathered together in a close group of compounds, unified by their common crystal structure in a way similar to what was found for the heavy alkali metal hydrides KH, RbH and CsH. Another interesting characteristic of the present phonon spectral data is the softening of both “A” and “B” optical bands while the cation atomic number increases, where “A” moves from the energy range (71-101) meV to (6794) meV, while “B” from (111-141) meV to (102-133) meV. In addition, one can observe that “A” becomes globally sharper moving from CaH2 to BaH2. This effect present in Σ(Q,E) has probably to be related to the flatness of the corresponding phonon dispersion curves at the edge of the first Brillouin zone. On the contrary, “B” shows no sign of such a shrinking. In Fig. 7, a detailed comparison between IINS and ABINIT Σ(Q,E) curves is also shown and one can easily observe an overall satisfactorily agreement in all cases. However, for BaH2 the comparison between experiment and simulation, though globally acceptable, does not result as good as for the other two hydrides. For example, the positions and the heights of the second and third peak (at 66.5 meV and 68 meV, respectively) are not precisely reproduced by ABINIT, and, in addition, all the first three simulated peaks exhibit a certain width which reveals a slightly too large dispersion of the “A” optical phonon bands. Similar differences are also visible in the CaH2 simulated spectrum, but to a less severe extent. Once again, the effect of the experimental energy resolution has been also checked, but found irrelevant in the plotted spectral range (50 meV<E<175 meV). With the help of the ABINIT estimates of phonon polarization vectors, it is possible to definitively confirm the physical interpretation of the spectral branches “A” and “B” proposed for CaH2 in Ref. [21], i.e. the former being caused by one type of H atom (H2) having an approximately square pyramidal coordination (5 metal neighbor atoms), while the latter connected to another type of H (H1) with an almost tetragonal coordination (4 metal neighbor atoms). Simulation data are reported in Fig. 8. On the other hand, “C” comes out to be related only to multi-phonon excitations (as shown by the simulated

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Figure 8. One-phonon (fundamental) component of the generalized self inelastic structure factor for CaH2 derived from ab-initio simulations. The contributions from the two non-equivalent hydrogen atoms are plotted separately: dotted red line for H2, and dash-dotted green line from H1. The sum of these two contributions is also reported (full blue line) and vertically shifted for graphical reasons. Symbols “A” and “B” are explained in the main text.

one-phonon components reported in Fig. 7), and this is why it has not been considered in the present discussion.

Conclusion and perspective In the present study we have reported incoherent inelastic neutron scattering spectra from alkali metal hydrides (LiH, NaH, KH, RbH and CsH) and orthorhombic alkaline earth hydrides (CaH2, SrH2 and BaH2) measured at T<20 K in the energy and momentum transfer ranges 3 meV<E<500 meV and 2.8 Å-1<Q<16.5 Å-1.

From the medium-energy region of these spectra (namely 50–150 meV, coinciding with the optical phonon bands), we were able to extract accurate generalized self inelastic structure factors and, in the case of rock-salt structures (LiH-CsH), hydrogen-projected densities of phonon states too.

These experimental spectral functions were then compared to equivalent results obtained from ab-initio lattice dynamics simulations, operated through the ABINIT code [40], and based on density functional theory and pseudo-potentials.

The overall agreement between neutron and ab-initio data turned out to be very good for the alkali metal hydrides, especially impressive for the three heaviest compounds: KH, RbH and CsH. As for the comparison between neutron and ab-initio data on orthorhombic alkaline earth hydrides, it came out to be satisfactory, even

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though some discrepancies still appeared in the first optical phonon zone, especially in the case of barium hydride, where peak positions, heights and widths were not perfectly reproduced by simulations. However, the most interesting result provided by the ABINIT simulations for this class of materials is probably the separation of the spectral contributions coming from the two nonequivalent H atoms in the hydride lattice.

This gives a strong and quantitative support to the recent physical interpretation of the spectral features proposed by Morris et al. for CaH2 [21], and is easily extendable to all the orthorhombic alkaline earth hydrides.

All these findings prove that, at least for the simple class of binary ionic hydrides, a quantitative agreement between experimental and ab-initio data is possible, not only for static (lattice parameters) and macroscopic quantities (bulk modulus, cohesive energy etc.), but also for the issue of the microscopic hydrogen dynamics.

Thus incoherent inelastic neutron spectroscopy technique has proved to be not only a reliable method for the investigation of the H dynamics in metal hydrides [48], but also a stringent and demanding validation tool for lattice dynamics simulations of these technologically relevant materials.

These conclusions pave the way for a broader investigation of more complex compounds such as borohydrides and aluminohydrides.

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Acknowledgements The authors are deeply indebted with Dr. A. J. RamirezCuesta (Rutherford Appleton Laboratory, Great Britain) and Prof. G. Barrera (Universidad Nacional de la Patagonia SJB, Argentina), and with Dr. G. Auffermann (MaxPlanck Institut, Germany) for their crucial scientific contributions in the ab-initio simulations and the sample preparation, respectively. In addition, the skillful technical help of the ISIS User Support Group is gratefully acknowledged. This work has been partially supported by Ente Cassa di Risparmio di Firenze through the Firenze Hydrolab project.

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6. J. M. Besson, G. Weill, G. Hamel, R. J. Nelmes, J. S. Loveday, and S. Hull, Phys. Rev. B 45, 2613 (1992) and references therein.

7. A. C. Ho, R. C. Hanson, and A. Chizmeshya, Phys. Rev. B 55, 14818 (1997) and references therein.

8. M. G. Zemlianov, E. G. Brovman, N. A. Chernoplekov, and Yu. L. Shitikov Inelastic Scattering of Neutrons vol. II (Vienna, IAEA, 1965) p.

431; J. L. Verble, J. L. Warren, and J. L. Yarnell, Phys. Rev. 168, 980 (1968).

9. A. D. B. Woods, B. N. Brockhouse, M. Sakamoto, and R. N. Sinclair, Inelastic Scattering of Neutrons in Liquids and Solids (IAEA, Vienna, 1961) p. 487 (contains raw neutron spectra from LiH and NaH).

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12. G. Auffermann, G. D. Barrera, D. Colognesi, G. Corradi, A. J. RamirezCuesta, and M. Zoppi, J. Phys.: Condens. Matter 16, 5731 (2004).

13. R. W. G. Wyckoff, Crystal Structures, vol. I (Interscience, New York, (1963).

14. G. S. Smith, Q. C. Johnson, D. K. Smith, D. E. Cox, R. L. Snyder, R.-S. Zhou, and A. Zalkin, Solid State Commun. 67, 491 (1988).

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16. J. Bergsma and B. O. Loopstra, Acta Cryst. 15, 92 (1962); A. F. Andresen, A. J. Maeland, D. Slotfeldt-Ellingsen, J. Solid State Chem.

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17. N. Brese, M. O’Keeffe, and R. Von Dreele, J. Solid State Chem. 88, 571 (1990).

18. W. Bronger, S. Chi-Chien, and P. Müller, Z. Anorg. Allg. Chem. 545, 69 (1987).

19. T. Sichla and H. Jacobs, Eur. J. Solid State Inorg. Chem. 33, 453 (1996).

20. G. J. Snyder, H. Borrmann, and A. Simon, Z. Kristallogr. 209, 458 (1994).

21. P. Morris, D. K. Ross, S. Ivanov, D. R. Weaver, and O. Serot, J. Alloys Comp. 363, 85 (2004).

22. A. J. Maeland, J. Chem. Phys. 52, 3952 (1969).

23. D. Colognesi, G. D. Barrera, A. J. Ramirez-Cuesta, and M. Zoppi, in press on J. Alloys Compd. (2006).

24. A. El Gridani and M. El Mouhtadi, Chem. Phys. 252, 1 (2000).

25. A. El Gridani and M. El Mouhtadi, J. Mol. Struct. (Theochem.) 532, 183 (2000).

26. A. El Gridani, R. Drissi El Bouzaidi, and M. El Mouhtadi, J. Mol. Struct. (Theochem.) 531, 193 (2000).

27. A. El Gridani, R. Drissi El Bouzaidi, and M. El Mouhtadi, J. Mol. Struct. (Theochem.) 577, 161 (2002).

28. H. Smithson, C. A. Marianetti, D. Morgan, A. Van den Ven, A. Predith, and G. Ceder, Phys. Rev. B 66, 144107 (2002).

29. D. Colognesi, M. Celli, F. Cilloco, R. J. Newport, S. F. Parker, V. RossiAlbertini, F. Sacchetti, J. Tomkinson, M. Zoppi, Appl. Phys. A 74 [Suppl. 1], 64 (2002).

30. H. H. Paalman and C. J. Pings, J. Appl. Phys. 33, 2635 (1962).

31. V. F. Sears, Neutron News 3, 29 (1992).

32. A. K. Agrawal, Phys. Rev. A 4, 1560 (1971); V. F. Sears, Adv. Phys. 24, 1 (1975).

33. M. M. Bredov, B. A. Kotov, N. M. Okuneva, V. S. Oskotskii, and A. L. Shakh-Budagov, Sov. Phys. Solid State 9, 214 (1967).

34. J. Dawidowski, F. J. Bermejo, and J. R. Granada, Phys. Rev. B 58, 706 (1998).

35. D. Colognesi, C. Andreani, and E. Degiorgi, J. Neutron Res. 11, 123 (2003).

36. P. S. Goyal, J. Penfold, and J. Tomkinson, The influence of multiple scattering on the inelastic neutron scattering spectra of molecular vibrations, RAL 86-070, unpublished, 1986.

37. R. Baddour-Hadjean, F. Fillaux, N. Floquet, S. Belushkin, I. Natkaniec, L. Desgranges, and D. Grebille, Chem. Phys. 197, 81 (1995).

38. A. J. Ramirez-Cuesta, Comp. Phys. Commun. 157, 226 (2004).

39. V. F. Turchin, Slow Neutrons (Israel Program for Scientific Translations, Jerusalem, 1965).

40. X. Gonze, J.-M. Beuken, R. Caracas, F. Detraux, M. Fuchs, G.-M. Rignanese, L. Sindiç, M. Verstraete, G. Zerah, F. Jollet, M. Torrent, A. Roy, M. Mikami, Ph. Ghosez, J.-Y. Raty, and D. C. Allan, Comp. Mat. Sc. 25, 478 (2002).

41. L. Bellaiche, J. M. Besson, K. Kunc, and B. Lévy, Phys. Rev. Lett. 80, 5576 (1998).

42. S. Goedecker, M. Teter, and J. Hutter, Phys. Rev. B 54, 1703 (1996); J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 77, 3865 (1996).

43. N. Troullier and J. L. Martins, Phys. Rev. B 43, 1993 (1991).

44. C. Hartwigsen, S. Goedecker, and J. Hutter, Phys. Rev. B 58, 3641 (1998).

45. J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 77, 3865 (1996).

46. G. D. Barrera, D. Colognesi, P. C. H. Mitchell, and A. J. RamirezCuesta, Chem. Phys. 317, 119 (2005).

47. X. Gonze and C. Lee, Phys. Rev. B 55, 10355 (1997).

48. D. K. Ross in H. Wipf (Ed.), Hydrogen in Metals, vol. III (Springer, Berlin, 1997) p. 153.

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Neutron-resonance capture as a tool to analyse the internal compositions of objects non-destructively H. Postma, Delft University of Technology, Mekelweg 15, 2629 JB Delft, the Netherlands

P. Schillebeeckx, EC-JRC IRMM, Retieseweg, Geel, Belgium

Abstract Neutron resonance capture analysis (NRCA) is a non-destructive method for analysing the bulk composition of materials and objects. It has been developed at the GELINA facility of the Institute for Reference Materials and Measurements (IRMM) in Geel (B) as a joint project with the Delft University of Technology. In this paper some features of NRCA are discussed on the basis of results obtained in the field of archaeology.

detecting the prompt gamma rays emitted after neutron capture. The energies of captured neutrons can be determined with the time-of-flight (TOF) method with neutrons travelling a known distance. This method requires a pulsed neutron source, which provides the start pulse for the TOF measurement. The stop pulse is generated by detection of the prompt gamma rays. It is not necessary to know the energy of the prompt gamma rays with a high resolution. Therefore, large scintillation detectors, not necessary with good energy resolution, but with a good time resolution can be used.

In addition, gamma rays can be accepted over a wide energy range, typically from about 300 KeV up to the neutron binding energy. Together with the fact that capture events are followed by several gamma-ray transitions in cascade, it is possible to obtain large detection efficiencies for capture events. Resonance capture as a function of neutron energy is the basis of the analytical method “Neutron Resonance Capture Analysis (NRCA)”.

NRCA has been explored at the GELINA facility of the IRMM in Geel (B) in a joint project with the Delft Univer-

Introduction Neutrons are used in various ways to analyse the elemental compositions, crystallographic structures and texture of archaeological and art objects, and for radiography and imaging of objects. One of the analytical methods is based on the occurrence of resonances in neutron capture cross sections. Since resonances occur at neutron energies specific for each nuclide, they can be used to recognize elements. In addition, the areas of resonance peaks provide information about elemental amounts. Resonance capture can be observed easily by

Figure 1. A schematic drawing showing the TOF system at the GELINA facility.

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sity of Technology in the Netherlands with applications in archaeology, the nuclear field and for the characterisation of reference materials. In this paper mainly the use of NRCA for archaeological and art objects is considered.

Experimental facility The basic element of the GELINA facility is a linear accelerator producing very short pulses of electrons with energies from 70 to 150 MeV, with a repetition rate up to 800 Hz and a maximum power of 10 kW. Stopping these electrons in uranium produces Bremsstrahlung, which in turn generates neutrons by photonuclear and photofission processes. Moderation in two water containing Betanks close to the uranium target produces a ´´white´´ spectrum of neutrons. Above about 1 eV the neutron flux is in first approximation proportional with the inverse of neutron energy. Details of the GELINA facility and a general review of the neutron-nuclear research carried out at this facility are discussed in another contribution to this issue [1]. Figure 1 shows a schematic presentation of the linac, neutron production target and TOF system.

In the more recent NRCA experiments two C6D6-based liquid scintillation detectors (7.5 cm thick and 10 cm in diameter) are used as capture detectors. They are placed at a distance of about 7 cm from the centre line of the neutron beam. The objects can be positioned at a distance of about 15 or 30 m from the pulsed neutron source.

The beam diameter at the sample position is about 7.5 cm. Figure 2 shows a set-up with two C6D6 detectors viewing from opposite sides a prehistoric bronze axis.

Shielding such detectors against neutrons scattered from

these detectors as much as possible. Another advantage of C6D6 is its short decay time, resulting in a time resolution better than 1 ns. In addition, their response is well understood and they have sufficient energy resolution to control the selected energy range (0.3 to 10 MeV).

Normally a cadmium filter (0.75 mm thick) is placed early in the beam to remove so-called overlap neutrons below 0.7 eV. To avoid overloading of the detectors by Bremsstrahlung flashes, filters of lead (1.5 cm thick), or bismuth (1.5 cm thick) and lately also sulphur (5.0 cm thick) are used.

Features of NRCA In figure 3 an example of a TOF capture spectrum with a prehistoric bronze axe obtained at the 29 m measurement station is shown. The spectrum shows the detector efficiency of the capture detection system as a function of the TOF of the neutron creating the capture event. (NB: this is not a gamma-ray spectrum as some people tend to think.) The time-of-flight of the neutron, Tn, can be converted to the neutron energy, En, using the relation:

⎛ L⎞ 1 En = mn ⎜ ⎟ 2 ⎝ Tn ⎠

2 (1)

where L is the flight path length and mn the neutron mass. At the top of the figure the energy scale is indicated. Some of the most important resonances are marked in this figure, for copper at 230, 578, and 994 eV, and for

Figure 2. Two C6D6 detectors opposite to each other with respect to the object, located at the centre of the neutron beam. The object is a socketed bronze axe.

Figure 3. Example of a TOF-capture spectrum obtained for a prehistoric bronze axe with flight path of 28.615 m. Some resonance peaks are indicated.

the object is not necessary because of their very low neutron sensitivity. The only neutron-related background is due to capture in the surrounding materials producing a gamma-ray background.

Therefore, it is important to keep material away from

tin at 38.8 and 111 eV. Other marked peaks are from silver and antimony. This spectrum illustrates that many sharp resonance peaks occur which can be distinguished even in the keV region. This is due to the high-energy resolution of the GELINA facility.

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Figure 4. A parametric fit of a part of the TOF spectrum between 42 and 60 eV.

The spectrum in figure 3 also reveals that often TOF regions for minor or trace elements can be selected such that their detection is not hampered by the presence of other elements. For instance the minor elements Sb and Ag in bronze objects have resonances at 21.4 and 6.22 eV, respectively 5.19 eV (see figure 3) which are not influenced by the response due to the presence of resonances of other components, notably the main elements copper and tin. Since in addition the detection efficiency at the lower energies is very large minor components like Sb and Ag can be detected in the ppm range.

A qualitative analysis based on recognizing resonances can be done on-line during data acquisition and may already give a quick impression about the elemental composition. For a quantitative analysis the areas under resonance peaks must be determined. Many of the peaks in a spectrum like the one in figure 3 are sufficiently well separated to determine their areas by summing over the channels and subtracting the background determined from adjacent regions. For a better accuracy peak fitting is necessary. This is certainly the case for closely lying, partly overlapping peaks. Resonance peaks may show on their high energy sides rather broad structures or even a bump due to neutron scattering in the object followed by neutron capture. In fact the possibility of potentional and resonance scattering requires a detailed analysis. Fitting can be done applying a resonance shape analysis using codes such as REFIT developed by Moxon [2].

This code was primarily developed to determine resonance parameters from TOF-spectra of well-characterised samples of simpler forms. The code determines the full response of the detector system starting from first principles and accounts for the self-shielding and multiple scattering effect, the Doppler broadening, the time resolution of the TOF-facility, and other effects such as the neutron sensitivity of the detector system. Since NRCA is not intended to determine resonance parame-

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ters the simpler approach of parametric fitting of resonance peaks has mostly been used. This is demonstrated in figure 4 for the 47-eV antimony resonance with some neighbouring smaller peaks. The 47-eV peak is fitted as a Gaussian broadened Lorentz line, the other peaks and the high energy shoulder of the antimony peak, due to scattering plus capture, are fitted with Gaussian functions. This approach has shown to work satisfactorily. In the case of saturated resonance peaks more complicated line shapes should be taken into account.

There are two ways to derive the composition of an object. Absolute amounts of elements can in principle be determined if the neutron flux, the detection efficiency and other details determining the time resolution and peak shapes are well known. This approach using the REFIT code has been applied successfully in Ref. [3] for the determination of the amount of Gd in U-samples and for the determination of impurities in reference materials. Another way is to determine relative amounts of elements with respect to a major element on the basis of ratios of peak areas and compare them with those from calibration samples. In the case of bronzes relative amounts of the elements are determined with respect to copper. The weight ratio of two elements (I and II) can be determined with:

W(I) A(I, E I ) = Câ&#x2039;&#x2026; W(II) A(II,E II )

(2)

Figure 5. The ratio of the 230 and 578 eV peak areas as a function of thickness in gr.Cu/cm2 used to determine the thickness of a fragment of a bronze cauldron.

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where A(j,Ej) denotes the observed area of the resonance at energy Ej for elements j. The factor C can be determined from a calibration sample with a known ratio of the two elements I and II. There is an important aspect to be taken into account in the quantitative analysis; namely the self-shielding effect of resonances. That is, the number of neutrons at resonance energies diminish during passage of the beam through the sample by resonance capture and scattering. Especially for strong resonances self-shielding is an important phenomenon. The effect of selfshielding can be calculated as a function of penetration depth using the Doppler broadened total resonance cross section. The two resonance areas in eq.2 must be corrected for self-shielding, if necessary in a recurrent manner. Of course this also holds for calibration samples. This self-shielding effect might be seen as a drawback, however, it can be turned into an advantage. Due to self-shielding the area ratio of two resonances of different strengths varies with sample thickness. As a demonstration figure 5 shows the ratio of the areas of the 230- and 578-eV copper resonances. This ratio varies considerably with thickness. It has been used to estimate the Cu thickness of a fragment from a bronze caul-

dron (7th cBC and excavated in Satricum) as a check on the correctness of the analysis [4].

If elements show up with several resonances in a capture spectrum, the weight ratio can be determined on the basis of a number of resonance pairs. For bronzes the Sn/Cu weight ratio is obtained from six pairs of resonances using three for copper (at 230, 650 and 994 eV) and two for tin (38.8 and 111 eV).

Figure 6 shows the result in case of an Etruscan votive with the data uncorrected and corrected for self-shielding [5]. The resulting values of the Sn/Cu weight ratio are in excellent mutual agreement after applying the self-shielding correction. Inconsistent weight ratios indicate an inhomogeneous composition. The occurrence of resonances of different strengths is an additional powerful feature of NRCA. Strong resonances are very suitable for detecting minor and trace elements often in the ppm range. The weaker resonances are perfect to investigate major elemental components of an object. If a strong resonance of a major element is investigated, it provides information of this element only in a surface layer of the object.

With the excellent time resolution of the GELINA facility high-energy resonances can be included in the analyses.

The upper energy limit depends on the complexity of

Figure 6. The Sn/Cu weight ratio determined for 6 pairs of resonances uncorrected and corrected for self-shielding for an Etruscan statuette.

Figure 7. Three Cu-resonances and one Pb-resonance in the region of 3250â&#x20AC;&#x201C;3650 eV used to determine the Pb/Cu weight ratio of an Etruscan votive.

Figure 8. Two bronze statuettes, one is a genuine Etruscan artefact and the other a later imitation (probably from the Renaissance period).

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the TOF spectrum and thus on the kind of material. For materials like marble resonances up to about 30 keV can be used [6]. Since capture spectra of ancient bronze objects are often complicated mainly due to the minors As, Sb and Ag, the upper limit is at about 10 keV. That means that lead, which has its lowest useful resonances at about 3 keV, can be included in the analysis. Lead is an important element in bronze objects since it is often added in considerable quantities. In bronze objects lead can be detected with concentrations above about 1 %.

Figure 7 shows a section of the TOF spectrum between 3250 and 3650 eV showing the 3357-eV resonance of 206 Pb and three Cu-resonances at 3310, 3503 and 3588 eV. Since these four resonances are weak the Pb/Cu weight ratio can be obtained with at most small self-shielding corrections.

Short review of applications NRCA has been applied to a considerable number of artefacts, so far mainly bronze objects. A series of Etruscan statuettes from a collection originally owned by earl Corazzi of Cortona (I), but bought by the Dutch government in 1826 and now at the National Museum of Antiquities in Leiden (NL) was studied. It turned out that it was possible to distinguish suspected fakes from genuine statuettes on the basis of the elemental compositions [5]. The conclusion was based on the observation that in some of these statuettes several per cents of zinc occur. With the smelting technique available to the Etruscan smiths, not more than a fraction of a per cent of zinc can enter into bronze. Two Etruscan objects, one genuine and one false, are shown in figure 8.

A number of NRCA measurements at GELINA concerned single objects. One of them was an antique commemorative plaque from the West-African country Benin, of which the originality was questioned. The determination of the composition was helpful and suggested that it is indeed genuine and by comparison datable to the period of 1725 to 1897 [7]. A recent project concerns the elemental compositions of bronze prehistoric axes from north-west Europe. This may be helpful in understanding production methods, trade relations in this part of Europe and the usage of these axes. For example one type of axe has such thin walls that it is unsuitable for cutting. It is suggested that it may have been used for ceremonial purposes. There are remarkable differences in the compositions of prehistoric axes, which might be related to differences in local techniques and availability of metals.

There are other fields in which NRCA can be applied.

One concerns the study of the "poison" Gd in nuclear fuel material. NRCA can be used to detect other isotopes produced in nuclear reactor processes and for the characterisation of reference material [3].

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Conclusion The above examples show that even in a restricted field like bronze artefacts a lot of interesting results can be obtained. Probable even more so if NRCA is combined with results from other neutron based techniques as PGAA and TOF neutron diffraction, and the imaging method to be developed in the Ancient Charm project. The latter is important for inhomogeneous objects.

A comparison of NRCA and PGAA as elemental analysis techniques is discussed in Ref. [8].

In conclusion the following statements can be made: • NRCA is fully non-destructive, it is not necessary to take samples from an object or to remove some of the patina, • The residual activation is negligible, • The existence of weak and strong resonances provides an interesting flexibility for the analysis, and • The high penetrability of neutrons is an important feature of neutron based analytical techniques.

Acknowledgements We like to sincerely thank the National Museum of Antiquities in Leiden (NL) for the loan of several bronze artefacts.

References 1. W. Mondelaers and P. Schillebeeckx, “GELINA, a neutron time-of-flight facility for high-resolution neutron data measurement”, in this issue.

2. M. Moxon, “REFIT2: A least Squares Fitting Program for Resonance Analysis of neutron Transmission and capture Data,” NEA-0914/02 (1989) 3. P. Schillebeeckx, A. Borella, A. Moens, R. Wynants, M. Moxon, H. Postma, C.W.E. Van Eijk, "The use of Neutron Resonance Capture Analysis to determine the elemental and isotopic composition of nuclear material", Proceedings of the 27th Annual Symposium on Safeguards and Nuclear Material Management, London, United Kingdom, May 10-12, (2005), Proc. ISBN 95-894-9626-6.

4. H. Postma, M. Blaauw, P. Schillebeeckx, G. Lobo, R. Halbertsma and A.J. Nijboer, "Non-destructive elemental analysis of copper-alloy artefacts with epithermal neutron-resonance capture", Czech. J. of Physics 53 (2003), A233-249.

5. H. Postma, P. Schillebeeckx and R. Halbertsma, "Neutron Resonance Capture Analysis of some genuine and fake Etruscan Copper-alloy statuettes", Archaeometry 46 (4) (2004), 635-646.

6. R.C. Perego, H. Postma, M. Blaauw, P.Schillebeeckx, A. Borella, "Neutron Resonance Capture Analysis: improvements of the technique for resonances above 3 keV and new applications", Proceedings MTAA11 conference, Univ. of Sussex, Guildford (UK) 2024 June 2004, to be published in J. of Radioanal. Nucl. Chem.

7. M. Blaauw, H. Postma and P. Mutti, "An attempt to date an antique Benin bronze using neutron resonance capture analysis", Applied Radiation and Isotopes 62 (2005) 429-433.

8. H. Postma and P. Schillebeeckx, "Non-destructive analysis of objects using neutron resonance capture", J. of Radioanal. Nucl. Chem. 265 (2005) 297-302.

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GELINA, a neutron time-of-flight facility for high-resolution neutron data measurements W. Mondelaers and P. Schillebeeckx, EC-JRC- IRMM, Retieseweg 111, Geel, Belgium Abstract Accurate neutron data are required for the assessment of safety aspects of nuclear power installations or for the design of new innovative concepts like nuclear waste transmutation or accelerator driven systems. For the measurement of such data in the resonance region an extremely good energy resolution is required, only achievable using a pulsed white-spectrum neutron source in combination with time-of-flight measurements. The Geel Electron LINear Accelerator Facility (GELINA) at the Institute for Reference Materials and Measurements (IRMM) of the European Commission’s Directorate-General Joint Research Centre (JRC) is especially designed for such purposes. Within the framework of the EURATOM ‘Transnational Access to Large Infrastructure’ programme, JRC-IRMM is able to offer, via the NUDAME project, beam time to external users from EU member countries and associated states.

Introduction The development and improvement of a comprehensive cross section database is essential for many areas of research and technology. For nuclear power production, neutron-induced reactions are definitely the most important interactions. Many interaction types may occur in numerous isotopes. A precise knowledge of neutron cross sections, over a broad energy range, is of a great importance for a proper account of reaction rates and the detailed neutron flux distributions in many nuclear applications. They are vital when evaluating the safety and risks related to the operation of nuclear power plants and to nuclear waste management. Also the development of innovative systems like accelerator-driven transmutation systems or new concepts of nuclear power production must rely on complete, accurate and consistent neutron data libraries. Reducing uncertainties in the neutron cross section data can result in an enhanced safety and efficiency of present and future nuclear power systems [1]. Accurate neutron cross sections play a crucial role not only for nuclear power, but also in many other disciplines such as astrophysics, medicine, and security [2, 3, 4].

In the energy interval from thermal neutron energies to a few MeV the neutron cross sections have a resonancetype energy dependence and large differences exist between the neighbouring isotopes. In the resonance re-

gion, two energy domains need to be distinguished: • the resolved resonance region where the neutron cross sections reveal a complicated resonance structure, • the unresolved resonance region, where the measured width of the resonances is larger than the resonance spacing, and the resonances appear to be overlapping.

The resonance structure, which largely differs from isotope to isotope, cannot be predicted or reproduced by models. Therefore, experiments with high energy resolution over the whole spectrum are required. These measurements allow extraction of the resonance parameters that describe the cross sections in detail. Accurate resonance parameters are calculated by using the technique of resonance shape analysis [5]. The required measurement accuracy can only be obtained at neutron Time-OfFlight (TOF) facilities especially designed for very highenergy resolution measurements [6].

In a TOF facility, the neutrons used for the neutron cross section measurements are produced by the impact of a short pulse of high-energy particles on a neutron-pro-

Figure 1. Aerial view of the GELINA time-of-flight facility

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ducing target. The impinging particles can be: • electrons that create neutrons via the production of bremsstrahlung and consecutive photonuclear reactions, or • protons that generate neutrons via the spallation reaction.

The TOF-facility GELINA The TOF-facility GELINA has been especially designed and built for high-resolution cross section measurements. It is a multi-user facility, serving up to 12 different experiments simultaneously, and providing a pulsed white neutron source, with a neutron energy range between 1 meV and 20 MeV. The installation is operated in shift work on a 24 hours/day basis, for about 100 h per week. Figure 1 shows an aerial view of the GELINA facility. Neutrons are produced in bunches of less than 1 ns duration, at repetition rates up to 800 Hz. The total neutron flux of the target is 3.4 x 1013 neutrons/s. This flux is rather low compared to the neutron facilities where scattering and diffraction are used as a tool for structure and dynamics analysis, applied in many scientific and technological domains. Such investigations require high fluxes of neutrons at very long wavelengths. For the study of the basic interaction mechanism of neutrons with nuclei (total, capture, fission, inelastic scattering, and charged-particle production cross section measurements) energy resolution in the resonance region is the most important design criterion.

Improvement of the energy resolution, while maintaining good neutron source strength has been a continuing

Figure 2. Scheme of the GELINA linear electron accelerator

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effort at GELINA [7, 8, 9]. Among the pulsed white spectrum neutron sources available in the world, GELINA is the one with the best energy resolution. The resulting excellent neutron energy resolution is made possible by a combination of four specially designed and distinct units: • a linear electron accelerator delivering a pulsed electron beam, • a post-acceleration relativistic-energy compression magnet system, • a rotary mercury-cooled uranium target, • 12 different flight paths, ranging from 10 m up to 400 m.

Linear electron accelerator A schematic overview of the electron accelerator is given in figure 2. The pulsed electron beam is generated in an injector with a Pierce-type triode gun. The injected electron pulses have a duration of 10 ns and a very high peak current of 12 A. The linear accelerator consists of three S-band accelerator sections operating at a frequency of 2999 MHz. The electrons are accelerated along the axis of the sections by the longitudinal electric field of an electromagnetic wave travelling synchronously with the highly charged electron pulses. The accelerating waves in the sections are produced with three pulsed highpower klystrons. The klystrons are powered with linetype pulse power modulators. They deliver to each section 25 MW peak power wave trains of 2 µs at a maximum repetition rate of 800 Hz. The duration of a wave train is longer than the so-called filling time of an accel-

RESEARCH INFRASTRUCTURES

erator section (the filling time is the time required to fill a section completely with electromagnetic power – for GELINA the filling time is typically 1,2 µs). In this way all cavities from an accelerator section can be filled with electromagnetic power before an electron pulse is injected. The energy of the electrons in a pulse leaving the accelerator varies linearly from 140 MeV at the start of the pulse to 70 MeV at the end of the pulse. This is because the first electrons of a pulse ‘see’ the full accelerating field during their travel along the accelerator, all cavities being filled with the maximum power. Each electron extracts power from the wave. The electron pulse is so short that there is not enough time to replenish the consumed power in the cavities during the duration of the electron pulse. The following electrons in a pulse experi-

ence a lower accelerating field than their forerunners. As a result of this so-called transient beam loading, the energy of the electrons is decreasing monotonically, from the beginning to the end of the pulse. This intrinsic feature of time-energy relationship during the electron pulse is now fully exploited to compress further the electron pulse lengths in the compression magnet installed at the end of the accelerator [8].

Compression magnet Before hitting the neutron-producing rotary target, the electrons make a ‘looping’ in a specially designed 360° compression magnet. This magnet has a diameter of 3 m and a weight of 50 tons. It consists of five magnetic sectors with zero gradient fields and is designed to accept

Figure 3. Principle of post-acceleration pulse compression

Figure 4. Gelina target hall

Figure 6. Neutron-producing target with peripheral equipment

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the 50% electron energy spread in the beam of the accelerator. The operational principle of the relativistic postacceleration compression magnet is shown in figure 3.

The bending radius of an electron in a magnet is proportional with its energy. Therefore, the first highest-energy electrons in a pulse will follow a longer trajectory than the later ones. Since all electrons have a speed close to the velocity of light, this results in a delayed arrival of the leading edge of the pulse at the exit of the magnet as compared with the arrival of the trailing edge. The magnet is designed such that all electrons of a 10 ns pulse, entering the magnet, will leave the compression magnet within a time bin of 1 ns. The peak current rises by this charge conserving compression from originally 12 A to about 120 A at the exit of the magnet. Figure 4 shows a photo of the target hall, in which the position of the compression magnet is shown, with respect to the neutronproducing target.

Neutron-producing target After the compression magnet the high-energy electrons impinge on a rotating neutron-producing target [10]. The rotary target consists of a U-Mo alloy with 10wt% of Mo, cooled with liquid mercury and sealed in stainless steel.

The neutron target, designed for optimum neutron production, has to withstand the full electron beam power (10 kW) almost completely dissipated in the target. A lay-out of the target is shown in figure 5. The electrons are decelerated and produce high-energy photons via the Bremsstrahlung process. These photons may interact with target nuclei and produce neutrons via (Îł,n) and to

Figure 5. Scheme of neutron-producing target

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a much lesser extent by (Îł,f) reactions. Uranium is chosen as target material because it favours the production of photons in the Bremsstrahlung process and neutrons by photon-induced nuclear reactions. Above ~30 MeV electron energy, the neutron production rate is nearly proportional to the electron beam power. The use of uranium increases the total neutron yield by a factor ~2 compared with another high-Z target, such as tantalum.

From a thick uranium target roughly 6 neutrons are emitted per 100 electrons of 100 MeV. The power density in the body, deposited by the electron beam may reach 10 kW/cm3. Therefore the target is rotating in the beam.

Mercury is chosen as a coolant, mainly to avoid neutron moderation.

The target delivers an average neutron intensity of 3.4 x 1013 neutrons/s. In order to have a significant number of neutrons in the energy range below 100 keV, two light-water moderators are placed above and below the existing target. The partially moderated neutrons have an approximate 1/E energy dependence plus a Maxwellian peak at thermal energy. Two flux set-ups are available: one optimised for energies below 500 keV by using neutrons coming from the moderators and one with fast neutrons emerging directly from the uranium.

Based on the required energy range in a particular measurement station, shadow bars are properly placed between the source and the flight path to shield unwanted neutrons. Further tailoring of the spectral shape is done with movable filters. Figure 6 shows a photo of the rotating target, collimators and shadow bars and the neutron shutters, leading to the flight paths.The present rotary

RESEARCH INFRASTRUCTURES

target has been designed taking into account the need to the limit the target-related contribution to the neutron energy resolution. A project has been launched in order to improve the accuracy of the high-resolution neutron cross-section measurements by designing a new target configuration. A compact stationary target has been designed, which can reduce further the target-related inaccuracy, while preserving, and even enhancing the timeaveraged neutron flux in all relevant neutron energy ranges [9, 11].

Figure 7 shows the absolute neutron flux of the moderated spectrum that was measured in the energy range from 25 meV to 200 keV by Borella et al. [12]. The results are compared with MCNP4C3 Monte Carlo calculations performed by Flaska et al. [9]. Figure 8 shows the comparison of similar calculations with the absolute neutron flux of the unmoderated spectrum in the energy range from 200 keV to 20 MeV, as measured by Mihaelescu et al. [13].

Neutron flight paths and measurement stations In order to apply the TOF technique, 12 flight-paths are installed in a star-like configuration around the neutron production target, schematically shown on the scheme in figure 9. The flight tubes are under vacuum, they have a diameter of 50 cm and their lengths range up to 400 m.

Several measurement stations are installed at different distances (with nominal distances of 10, 30, 50, 60, 100, 200, 300 and 400m) along the flight paths. These experimental stations are equipped with a wide variety of sophisticated detectors, and data acquisition and analysis

Figure 7. Absolute neutron flux per unit lethargy of the moderated neutron spectrum at 10 m and GELINA operating at 40 Hz.

systems, especially designed for neutron-induced total and partial cross-section measurements with an exceptional precision and energy resolving power. Modern detection techniques such as advanced HPGe Comptonsuppressed detectors and data acquisition systems based on fast signal digitisers are currently implemented.

Many types of neutron cross section measurements are possible. There are neutron measurement set-ups for transmission experiments, capture, fission, elastic and inelastic cross sections, and flux measurements.

Transmission measurements can be performed at a 25m, 50m, 100m, 200m and 400m flight path using Li-glass detectors, plastic scintillators or NE213 scintillators. To study the Doppler broadening one of the transmission measurement stations is equipped with a cryostat, which is able to cool the samples down to 10K. Fission cross section measurements are performed at a 8m and 30 m station using Frisch gridded ionisation chambers and surface barrier detectors. These measurement stations are also used to study (n,p) and (n,Îą) reactions. Inelastic scattering reactions are studied at a 30m or 200m station using HPGe-detectors. Capture measurement systems, using C6D6 scintillators or HPGe detectors, are available at a 15m, 30m and 60m flight path.

Transnational Access via NUDAME Besides the GELINA facility, the JRC-IRMM is also equipped with a Van de Graaff (VdG) facility. At the VdG quasi mono-energetic beams of neutrons are produced in the energy range up to 24 MeV, using different charged-particle induced reactions. The high-resolution

Figure 8. Absolute neutron flux per unit lethargy of the unmoderated neutron spectrum at 200 m and GELINA operating at 800 Hz.

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measurements at GELINA can be complemented by measurements at the VdG, especially in the MeV neutron energy domain where the resonance structure of the cross-sections is averaged out. The VdG is a 7 MV electrostatic accelerator for the production of continuous and pulsed proton-, deuteron- and helium ion beams.

Ion beams can be produced with a current of up to 60 µA in DC mode and up to 5 µA in pulsed mode. The pulse repetition rates are 2.5, 1.25 or 0.625 MHz. The energy of the mono-energetic neutrons is defined by using lithium, deuterium or tritium targets and choosing appropriate emission angles. Depending on the neutron energy up to 108 neutrons/s can be obtained.

Due to the combination of the GELINA white neutron TOF-facility and the quasi mono-energetic neutron source at the VdG, the Reference Laboratory for Neutron Measurements at IRMM is one of the few laboratories in the world which is capable of producing the required accuracy of neutron data over a wide energy range from a few meV to about 24 MeV. These unique research capabilities offered at the two accelerators are an excellent opportunity for transnational collaborations in the field of transmutation research and innovative nuclear energy systems. To facilitate the access to the facilities for outside users, a project ‘NUclear DAta MEasurements at IRMM’ (NUDAME) has been launched within the framework of the Euratom Transnational Access programme. Applications for support can be submitted via the NUDAME website which can be found on the main web portal of IRMM [14].

Any type of experiment in the areas of radioactive waste management, radiation protection and other activities in the field of nuclear technologies and safety can be proposed provided our experimental infrastructure can offer a significant added value to the project.

Access to the IRMM accelerator installations implies the same scientific, logistical and technical support provided to all researchers of the Institute.

Figure 9. Scheme of flight path area

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Short overview of in-house research areas For the safety assessment of presently operating reactors reliable predictions must be made about their behaviour under different operating conditions. For these calculations the accurate knowledge of changes in neutron spectra are highly important. As an example, the neutron multiplicity averaged over the whole mass distribution is of crucial importance for the physics of conventional reactors and needs to be known with accuracy better than 1%. Researchers at IRMM are presently concentrating on neutron multiplicities, fission neutron spectra and delayed neutrons, total-absorption and neutron capture cross-sections, fission fragment yields and kinetic energy distributions. In view of the assessment of the temperature dependence of the reactor criticality Doppler broadening measurements have been carried out on 238U, 237Np and natHf at different temperatures.

Improved capture cross sections for various stable fission products are motivated by the objective to extend and optimize the fuel cycle associated with present nuclear power plants. These data are also important for criticality safety of spent fuel storage and transportation of spent fuel in licensed shipping casks. To improve these data, the IRMM started a collaboration with CEA Saclay (F) and ORNL (US) and initiated measurements at GELINA for 103Rh and 55Mn. The Generation IV International Forum (GIF) pursues the in-depth investigation of six advanced concepts for nuclear energy systems, with the objective to arrive at energy production with a largely reduced volume of high-level radioactive waste, proliferation resistant fuel cycles and much enhanced safety. Future hydrogen production is envisaged as well. The nuclear data requirements for the development of these systems address the same neutron-induced reactions as those for thermal systems, but extending into the 10-20 MeV range. At the GELINA TOF facility high-resolution cross section measurements will be carried out for the relevant isotopes

RESEARCH INFRASTRUCTURES

and reaction types. A key issue for the future of nuclear energy production is a satisfactory solution that must be elaborated for the disposal of nuclear waste. The research in this field concentrates on the chemical separation, called partitioning, of long-lived radioactive isotopes in the nuclear waste and subsequent transmutation into short-lived or stable isotopes. By exposing the materials to high neutron fluxes transmutation occurs via neutron capture or fission reactions. The goal is to burn the so-called long-lived fission products (LLFP) such as 99 Tc, 129I, and 135Cs, and minor actinides (MA) such as Np, Am, and Cm isotopes. In all cases the knowledge of the associated set of nuclear data is not complete. In order to improve the nuclear data high-resolution total and capture cross section measurements were performed at GELINA for the long-lived fission products 99Tc and 129I and for the minor actinide 237Np. Measuring 241Am is under preparation.

Different types of accelerator driven systems (ADS) for transmutation of nuclear waste have been proposed. The most promising one is based on a liquid Pb-Bi spallation target. Although the initial neutron energies resulting from spallation are in general above the energy range of GELINA, the neutron spectrum outside the target area and at larger distances approaches that of a conventional fast (or thermal) reactor. Using the TOF technique neutron capture cross-section measurements have been measured in the resonance region for 232Th, 206,207,208Pb, 209Bi and 235,238U. For Pb and Bi isotopes capture measurements must be combined with future total cross-section measurements in the resolved resonance region in order to lead to the unambiguous determination of the essential parameters. Elastic and inelastic scattering cross-section measurements have been carried out at GELINA for 23 Na, 27Al, 56Fe and 238U via (n,n’γ) experiments. The majority of basic and applied measurements in neutron physics are performed relative to cross-section standards. It is therefore essential that these standards are continuously improved and their underlying physical mechanisms are understood.

Under the steering of the OECD and the Data Centre of the International Atomic Energy Agency (IAEA) needs for new standards are identified and proposals are made for improvements of established standards. The detailed requirements for neutron data measurements, and in particular for improvements of the standards database, are collected in the high priority list of the NEA. For example, the 10B(n,α) 7Li reaction cross section, recently investigated at GELINA, is amongst the most important standards used in neutron measurements.

The techniques developed for high-resolution neutron cross section measurements in the resonance region generate also spin-off techniques, not directly belonging to our core-business. A new fully non-destructive method

‘Neutron Resonance Capture Analysis’ (NRCA) has been developed, in collaboration with the Delft University of Technology. NRCA allows the determination of the elemental composition of samples.

The method is based on the use of neutron resonances as fingerprints to identify and quantify elements. Details of the NRCA technique are discussed in another contribution to this issue [15].

References 1.

M. Salvatores, “Future nuclear power systems and nuclear data needs,” J. Nucl. Sci. and Techn., Suppl. 2, 4, (2002).

2.

M.S. Smith, “Nuclear data relevant to astrophysics,” J. Nucl. Sci. and Techn., Suppl. 2, 19, (2002).

3.

S.M. Qaim, “Nuclear data for production of new medical radionuclides,” J. Nucl. Sci. and Techn., Suppl. 2, 1272, (2002).

4.

T. Biro, “Neutrons as tools in safeguards and combating illicit trafficking of nuclear material,” Proceedings of the workshop The Nuclear Measurements and Evaluations for Applications (NEMEA2), Budapest, Hungary (November 5-8, 2003).

5.

M. Moxon, “REFIT2: A least Squares Fitting Program for Resonance Analysis of Neutron Transmission and capture Data,” NEA-0914/02 (1989).

6.

C. Coceva, M. Frisoni, M. Magnani, A. Mengoni, “On the figure of merit in neutron time-of-flight measurements,” Nucl. Inst. and Meth.

A, 489, 346-356, (2002).

7.

A. Bensussan, J.M. Salome, “Gelina: a modern accelerator for high resolution neutron time of flight experiments,” Nucl. Inst. and Meth., 155, 11-23, (1978)

8.

D. Tronc, J.M. Salome, K. Böckhoff, “A new pulse compression system for intense relativistic electron beams,” Nucl. Inst. and Meth., 228, 217-227, (1985).

9.

M. Flaska, A. Borella, D. Lathouwers, L.C. Mihailescu, W. Mondelaers, A.J.M. Plompen, H. van Dam, T.H.J.J. van der Hagen, “Modeling of the GELINA neutron target using coupled electronphoton-neutron transport with the MCNP4C3 code,” Nucl.

Inst. And Meth. A, 531, 392-406, (2004).

10. J.M. Salome, R. Cools, “Neutron producing target at GELINA,” Nucl.

Inst. and Meth., 179, 13-19, (1981).

11. M. Flaska, D. Lathouwers, A.J.M. Plompen, W. Mondelaers, T.H.J.J. van der Hagen, H. van Dam, “Potential for improvement of a neutron producing target for time-of-flight measurements,” Nucl.

Inst. And Meth. A, 555, 329-339, (2005).

12. A. Borella, “Determination of the neutron resonance parameters for 206Pb and of the thermal neutron capture cross section for 206Pb and 209Bi,” Ph.D. thesis, Ghent University, Belgium (2005).

13. L.C. Mihailescu, L. Olah, C. Borcea, A.J.M. Plompen, “A new HPGe setup at GELINA for measurement of gamma-ray production cross sections from inelastic neutron scattering,” Nucl. Inst. and Meth. A, 531, 375-391, (2004). http://www.irmm.jrc.be/html/homepage.htm 14. H. Postma and P. Schillebeeckx, “Neutron-resonance capture as a tool to analyse the internal compositions of objects non-destructively”, in this issue

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Courtesy: lightsources.org

Reactor Institute Delft and the R3 department The academic Dutch neutron facility M. Blaauw Reactor Institute Delft Mekelweg 15 2629 JB Delft The Netherlands

Early history of the institute The reactor embedded in the Reactor Institute Delft first came to Europe as a part of the “Atoms for Peace” exhibit in the late 1950s.

Near Schiphol airport, all those visiting the exhibit were allowed to climb a ladder, peer straight into the core and see the Cerenkov radiation. When the exhibit was discontinued, it was decided to keep the reactor in the Netherlands and found the Reactor Institute Delft, to be operated by the University of Delft. The reactor was upgraded

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from 100 kW to 2 MW over the years. The name of the institute changed a number of times, from its original name to “Interuniversitary Reactor Institute” to “Interfaculty Reactor Institute”, and back to “Reactor Institute Delft” (RID).

The first name changes corresponded to changes in ownership, the last one also denotes the regrouping of the scientific departments into a single department af the Applied Sciences Faculty named “Radiation, Radionuclides and Reactors” (R3), and the reactor and instrument opera-

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tions in the RID branch of the same Applied Sciences faculty.

Recent history and NMI3 transnational access In the 1990s, the original reactor containment building was extended with a beam-guide hall offering more neutron beams and more floor space to the instruments. Only a few years later, the main building was almost doubled in size, both with respect to laboratories and to office space. Last year, the RID already

M & N & SR NEWS

having been a member of the NMI3 (Integrated Infrastructure Initiative for Neutron Scattering and Spect ro s c o p y ) consortium for a while, it was decided within NMI3 to provide 120 days of beam time access to users from European and associated states through the transnational access mechanism. Only months after this decision becoming final, users are submitting proposals at a rate forcing us to implement peer review mechanisms. Our first official, enforced deadline for proposals will be January 1, 2007 as a result.

Unique and rare experimental opportunities The RID offers the only neutron beam facilities in a radius of 500 km, and that in an academic setting. Together with the R 3 department, a long-standing reputation for instrument innovation is being worked on continuously. We have several

unique experimental opportunities to offer as a result. To name a few: The innovative SESANS instrument that can see structures of up to 20 mm in real space. The very intense positron beam POSH (4x108 s-1), connected to a beautiful 2D-ACAR setup. The facilities for Instrumental Activation Analysis of samples up to 15 litres. More information on our facilities can be found on our website: www.rid.tudelft.nl.

The Radiation, Radionuclides & Reactors department Radiation is what binds the Radiation, Radionuclides & Reactors department together. However varied our areas of interest, whether they be materials, sensors and instrumentation, energy and sustainable production or health, all our research is somehow related to radiation. Today, the focus of the R3 research is on energy and health. The close collabo-

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ration with the RID not only guarantees access to the reactor and the irradiation facilities, but also results in three centres of knowledge: the Positron Centre, the Neutron Centre and the Netherlands Centre for Luminescence Dating (NCL). The confluence of all this knowledge makes our research unique in the Netherlands, perhaps even in Europe.

The R3 department consists of five sections: Physics of Nuclear Reactors (PNR) designs and analyses new nuclear reactor systems to improve the sustainability of nuclear power.

Fundamental Aspects of Materials and Energy (FAME) investigates functional and structural materials with a view to practical applications. The main focus is on the relationship between structure, dynamics and function on atomic and nanoscales. Solar-cell materials, hydrogen storage, batteries and related subjects are the current focus.

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M & N & SR NEWS

Neutron and Positron Methods in Materials (NPM2) develops instruments and methods for the optimal use of neutrons and positrons, ultimately for use within the large, international facilities – but to a first-generation user, one needs to come to Delft!

Radiation and Isotopes for Health (RIH) innovates and optimises the use of radiation and radioisotopes in the health sciences. The research focuses on innovative production pathways and applications of radioisotopes, but also on radioactive compounds, radiation burden and image quality in diagnostics and therapy.

Radiation Detection & Matter

(RD&M) performs fundamental and applied research on radiation sources, radiation detection principles, in particular luminescence and scintillation phenomena, and applications in medical diagnostics, therapy and dosimetry, humanitarian demining and security, neutron detection, geology, art and archaeology.

The future Just a few weeks ago, the director of R 3 and RID, Tim van der Hagen, stated that the prospects and future outlook for the Delft neutrons had never been better than right now. We

have detailed plans for installation of a cold neutron source at the Delft reactor, including instrument improvements that will be possible as result, as well as entirely new instruments currently only dreamed of.

The RID has a clearly defined obligation to maintain and improve the existing instruments, as well as to find and assist users from the outside world. Once, not so long ago, we kept our wonderful instruments and possibilities mostly to ourself.

Now, we are opening up and already the benefits of this attitude are becoming apparent.

New From ILL ILL Next standard proposal round The deadline for proposal submission to the ILL is Tuesday, 19 September 2006, midnight (European time).

Proposal submission is only possible electronically. Electronic Proposal Submission (EPS) is possible via our Visitors’ Club (www.ill.fr, Users & Science, Visitors’ Club, or directly at http://vitraill.ill.fr/cv/), once you have logged in with your personal username and password.

The detailed guide-lines for the submission of a proposal at the ILL can be found on the ILL web site: www.ill.fr, Users & Science, User Information, Proposal Submission, Standard Submission.

The web system will be operational from 1 July 2006, and it will be closed on 19 September, at midnight (European time).

You will get full support in case of computing hitches. If you have any difficulties at all, please contact our web-support (club@ill.fr ).

Instruments available The following instruments will be available for the forthcoming round:

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• powder diffractometers: D1A, D1B*, D2B, D20, SALSA • liquids diffractometer: D4 • polarised neutron diffractometers: D3, D23* • single-crystal diffractometers: D9, D10, D15*, VIVALDI • large scale structure diffractometers: D19, DB21, LADI • small-angle scattering: D11, D22 • reflectometers: ADAM*, D17 • small momentum-transfer diffractometer: D16 • diffuse-scattering spectrometer: D7 • three-axis spectrometers: IN1, IN3, IN8, IN12*, IN14, IN20, IN22* • time-of-flight spectrometers: IN4, IN5, IN6 • backscattering and spin-echo spectrometers: IN10, IN11, IN13*, IN15, IN16 • nuclear-physics instruments: PN1, PN3 • fundamental-physics instruments: PF1B, PF2 * Instruments marked with an asterisk are CRG instruments, where a

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smaller amount of beam time is available than on ILL-funded instruments, but we encourage such applications. You will find details of the instruments on the web: www.ill.fr/index_sc.html

Scheduling period Those proposals accepted at the next round, will be scheduled during the first two cycles in 2007.

Provisional Reactor Cycles for 2007* Cycle n° 146 (071)

From 30/01/2007 To

Cycle n° 147 (072)

From 04/04/2007 To

Cycle n° 148 (073)

24/05/2007

From 21/08/2007 To

Cycle n° 149 (074)

21/03/2007

10/10/2007

From 25/10/2007 To

20/12/2007

Table 1. The ILL reactor cycles in 2007. Start-ups and shut downs are planned at 8:30 am

M & N & SR NEWS

College Secretaries College 1- Applied physics, instrumentation & techniques: Emanuel Farhi College 2- Theory: Olivier Cepas College 3- Nuclear and Fundamental Physics: Torsten Soldner College 4- Structural and Magnetic Excitations: Martin Boehm College 5A- Crystallography: Paul Henry College 5B- Magnetism: Nolwenn Kernavanois College 6- Structure and Dynamics of Liquids and Glasses: Claudia Mondelli College 7- Spectroscopy in solid state physics and chemistry: Peter Fouquet College 8- Biology: Ingrid Parrot College 9- Structure and Dynamics of Soft-condensed Matter: Ralph Schweins

New keywords system for the colleges!

With the instrument SALSA fully operational, and the forthcoming commissioning of the Tomography station and SALSA (without forgetting FaME 38), an increase of proposals dealing with more applied engineering research is expected.

This raises the problem of properly judging these proposals: whilst some people would be interested in applied topics others would be interested in pure science only.

For this reason, we decided to include a new College – and correspondent subcommittee panel – in the proposal evaluation system:

An additional re-organisation of the Colleges 4 and 7 in terms of coherence, mainly aims at achieving a more straightforward attribution of proposals to both colleges. Magnetic and non magnetic excitations will be dealt in the future by college 4 and college 7, respectively.

A detailed keywords list is available on the ILL web (www.ill.fr) under www.ill.fr/pages/science/User/UK eywds.html

* Please note that these dates might change.

We therefore encourage you

College 1: Applied physics, instrumentation & techniques • 1-01 Metallurgy, strain/texture measurement and metal physics • 1-02 Tomography • 1-03 Applied sciences • 1-10 Instrumentation for neutron scattering • 1-20 Techniques for neutron scattering

to consult the ILL website, where possible changes will be indicated.

New From ILL AP.G.RA.D(E), Application of γ-ray diffraction (October-November 2006) The GAMS gamma-ray spectrometers at the Institut Laue-Langevin (ILL) have always been unique installations combining one of the world most intense continuous thermal neutron sources with the extraordinary resolving power of the twoaxis crystal spectrometers.

This combination delivers extraordinary results to various fields of physics. The majority of these contributions are related to the ongoing improvement in resolving power of the instruments.

This parameter has now approached its theoretical limit and therefore it is

the moment to discuss what future physics should be investigated on the GAMS spectrometers.

During the last few years a variety of new proposals for exciting applications at GAMS in very different fields have been made. Therefore, during the two days of the work-

shop we would like to bring together new and old GAMS users to help defining the future physics and technical developments of these spectrometers.

G. Cicognani

Further information on the workshop can be obtained from the website

www.ill.fr/apgrade/First-Announce.htm

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M & N & SR NEWS

Jefferson Lab’s CEBAF Continues Experiments While Gearing Up for an Increase in Energy The Department of Energy’s Thomas Jefferson National Accelerator Facility (DOE’s Jefferson Lab) in Newport News, Va., is home to the Continuous Electron Beam Accelerator Facility (CEBAF), an accelerator capable of providing a 5.75 GeV electron beam for research to any of its three experimental halls.

CEBAF uses a state-of-the-art photocathode gun system that is capable of delivering beams of high polarization and high current to two halls, while maintaining high-polarization, low-current beam to the third. A chopping system operating at 499 MHz is used to develop a 3beam 1497 MHz bunch train at 100 keV. The beam is then longitudinally

compressed in the bunching section to provide 2 picosecond bunches, which are then accelerated to just over 1% of the total machine energy in the remaining injector section.

The beam from the injector is accelerated through a unique recirculating beamline that looks much like a racetrack, with two linear accelerators (linacs) joined by two 180° arcs with a radius of 80 meters.

The total track measures about a kilometer in length. Twenty cryomodules, each containing eight superconducting niobium cavities, make up the two linacs. Liquid helium keeps the accelerating cavities superconducting at a temperature of 2 Kelvin. Quadrupole and dipole

magnets in the tunnel steer and focus the beam as it passes through each arc. More than 2,200 magnets are necessary to keep the beam on a precise path and tightly focused.

Beam is directed into an experimental hall’s transport channel using magnetic or radiofrequency (RF) extraction. The RF extraction scheme uses 499 MHz cavities, which kick every third bunch out of the machine. The accelerator can deliver the first four passes to one hall only; the fifth pass can be sent to all three halls simultaneously. The beam is sent into targets in any or all of the three experimental halls: Hall A, Hall B and Hall C. Hall A’s standard equipment includes a pair of High

Hall A. The GEn experiment, which measured the electric form factor of the neutron in Jefferson Lab’s Hall A, concluded data taking in May 2006.

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M & N & SR NEWS

Resolution Spectrometers (HRS), designed for electron and hadron detection. Hall B’s CEBAF Large Acceptance Spectrometer (CLAS) encapsulates the target, providing virtually 4π acceptance.

Hall C is highly versatile, allowing for large equipment installations, with two pieces of standard equipment, the High Momentum Spectrometer and the Short Orbit Spectrometer.

Jefferson Lab is a DOE Office of Science, Office of Nuclear Physics research facility. It was envisioned and requested by physicists as a necessary tool to answer emerging questions about the quark structure of matter in 1976, and construction of the facility began in 1987. CEBAF provided beam for its first set of experiments in 1994.

Research carried out at the Lab addresses questions in three main areas

in nuclear physics: the structure of nucleons, the structure of the nucleus, and symmetry tests in nuclear physics. For example, the GEn experiment in Hall A measured the electric form factor of the neutron at high Q2. Recent results on the electric form factor of the proton, GEp, showed that the ratio GEp/GMp decreases sharply as Q2 increases.

The same mechanisms that cause such a deviation should also be present in the neutron, but until this experiment, no accurate data existed at these momentum transfers. Hence, this test is essential for understanding the structure of the nucleon and for providing key information for the analysis of processes involving electromagnetic interactions with complex nuclei. CEBAF will continue its research program far into the future with the planned 12 GeV Upgrade. DOE recently awarded Jeffer-

son Lab Critical Decision One (CD-1) approval for the Upgrade, which moves the project from the Conceptual Design phase to the Project Engineering and Design phase.

The 12 GeV Upgrade Project will double CEBAF’s electron beam energy from 6 GeV to 12 GeV and will upgrade the scientific capability of four experimental halls (adding one new hall, Hall D).

The first Program Advisory Committee to review 12 GeV proposals will take place in August 2006; details may be found at: http://www.jlab.org/exp_prog/PA Cpage/PAC30/.

A.E. Ekkebus Spallation Neutron Source ORNL

Upgrade. The 12 GeV Upgrade of CEBAF will double the machine’s electron beam energy and provide increased scientific capability in four experimental halls.

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M & N & SR NEWS

Spallation Neutron Source Progress February 2006 Summary The SNS Project is 96.3% complete through December 2005 Strong safety performance continues as the project has worked in excess of 7.4 million hours, with only 2 lost work day (away) cases through December 2005.

Instruments The first procurement contract for sample environment equipment has been awarded.Magnetism Reflectometer components [instrument, omega, and detector stages] were moved into its cave. Hutch installation is complete.

Over 30 motor controls have been installed for instrument operation.

Phase 1 installation of the Fundamental Neutron Physics Beamline (BL-13) was completed in early February.

The first production detector for the POWGEN and Vulcan instruments was tested at the SNS test beam line at HFIR. The initial measured performance exceeded expectations.

Gluing of silicon crystals to backplates has been completed for total of six backscattering crystal assemblies for the backscattering spectrometer.

Bids for construction of the CNCS Satellite building are due later this month.

The first two sections of the ARCS neutron guide were successfully inspected at the manufacturer, with shipment beginning later this month.

Five choppers have been installed on the first three instruments.

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Target Significant activity is underway to prepare for the Target portion of the Accelerator Readiness Review that will be held in April.

All core vessel inserts, shutters, and shutter drives have been installed that were scheduled to be completed before CD-4. Full Operational Integrated System Tests of the target systems continue.

The shine shield blocks above the Target were installed and testing was completed for the primary and secondary containment exhaust.

Completed shutter testing for the three shutters required to be operational for CD-4.

Completed demonstration tests for target module replacement using only the remote handling equipment.

All of the remote handling tests and procedures have been completed.

Accelerator The SNS ring commissioning run in its 24/7 mode was concluded as planned on February 3. Installation of the remaining Ring-to-Target components is underway.

Project and Site Support The build-out of the CLO auditorium has begun with completion scheduled for May.

Future meetings and deadlines of interest to SNS users SNS Instrument Development Team meetings: NOMAD (disordered materials dif-

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fractometer), March 13, 2006, Baltimore (at APS) HYSPEC (hybrid spectrometer), April 7, 2006, Brookhaven SNAP (high-pressure diffractometer), April 10-11, 2006 Oak Ridge TOPAZ (single crystal diffractometer), May 8-9, 2006, Oak Ridge Workshop on Polarized Inelastic Neutron Scattering (PINS), April 6-7, 2006, Brookhaven. http://www.bnl.gov/pins/ Imaging and Neutrons, summer 2006, Oak Ridge, in preparation [http://www.sns.gov] International Symposium on Polymer Analysis and Characterization (ISPAC), June 12 - 14, 2006, Oak Ridge. http://www.chem.cmu.edu/ispac/ American Conference on Neutron Scattering, June 18-22, 2006, St. Charles, IL, http://acns2006.anl.gov.

Session on Noninvasive Scattering Techniques for Nanoaerosol Characterization: Neutrons, X-rays and Light, within the 25th annual meeting of the American Association for Aerosol Science and the 7th International Aerosol Conference, September 10-15, 2006, St. Paul, Minnesota. http://www.aaar.org/IAC2006/index.htm.

Short course: Neutron Scattering Applied to Earth Sciences, Mineralogical Society of America, December 7-8, 2006, Emeryville, CA. http://www.minsocam.org/msa/sc /neutron_descrptn.html.

A.E. Ekkebus Spallation Neutron Source ORNL

M & N & SR NEWS

FELBE: a new infrared free-electron-laser user facility M. Helm and P. Michel Forschungszentrum Rossendorf, P.O. Box 510119, 01314 Dresden, Germany

At the Forschungszentrum Rossendorf in Dresden, Germany, the superconducting electron accelerator ELBE (Electron Linear accelerator with high Brilliance and low Emittance) has come into operation in 2002 (for a layout of the building see Fig. 1).

It provides electrons with energies up to 40 MeV and an average beam

Yet one of the main tasks of the electron beam is to drive two infrared (IR) free-electron lasers (FEL), which will be briefly described in this article.

In May 2004, first lasing has been demonstrated [1] and by now the available wavelength range is 4 to 22 µm for electron energies between 15 an 32 MeV [2].

reviewed proposal system, being open to users worldwide.

In particular, users from EC and associated countries can be supported under the “Transnational Access” program within the EC funded ”Integrating Activity on Synchrotron and Free Electron Laser Science (IASFS)”. This latter project is an “Integrated Infrastructure Initiative” (I3)

The presently operating FEL is based on a 27-mm-period, hybrid permanent-magnet undulator (U27) with 2x34 periods, of the same type as employed at the Tesla Test Facility (TTF) at DESY, Hamburg.

Starting in 2005, the FEL has been operated as a user facility – under the name FELBE (www.fzrossendorf.de/felbe) – with a peer-

which comprises most synchrotron and FEL facilities in Europe and is coordinated by ELETTRA in Trieste.

In order to extend the available wavelength range, a second undulator (hybrid permanent magnet with 100 mm period and 38 periods) is presently being set up.

This second FEL is predicted to cover the far-infrared/THz range from

Figure 1. Layout of the ELBE building.

current of 1 mA, which are used to generate radiation and particle beams of several kinds: MeV bremsstrahlung for nuclear (astro)physics experiments, monochromatic hard-X-ray channeling radiation for radiobiological experiments, and in the near future also neutrons and positrons (for details, see www.fz-rossendorf.de/elbe).

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M & N & SR NEWS

Figure 2. Autocorrelation trace and corresponding spectrum of an FEL pulse at 11 µm. The inset gives the fitted width of the autocorrelation trace as well as the deduced effective pulse width.

Figure 3. Pump-probe signal of a semiconductor superlattice at two different wavelengths. For details, see Ref. 3.

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approximately 15 to 150 µm (the latter corresponding to 2 THz). In this wavelength range still no other highpower, narrow-band sources exist apart from FELs. The key feature which distinguishes FELBE from other FEL user facilities is the possibility of quasi cw operation (meaning a continuous micropulse train), made possible by the superconducting accelerator cavities.

These niobium RF cavities were also designed for the Tesla Test Facility and are kept at 2 K using superfluid He. The FEL thus provides picosecond optical pulses at a repetition rate of 13 MHz. In this mode, the average power can reach up to 10 W, corresponding to nearly 1 µJ pulse energy. For reduced average power, macrobunching is possible as well, yielding >100 µs long macropulses at a <25 Hz repetition rate.

By comparing autocorrelation traces with optical spectra the pulses have been proven to be bandwidth limited. At a fixed wavelength the pulse length (and thus the spectral width) can be varied by a factor of 5 by adjusting the cavity detuning and thus the gain.

An example is shown is Fig. 2, where autocorrelation and spectrum are plotted for the shortest pulses (0.9 ps) obtained so far at this wavelength of 11 µm (at shorter wavelengths also shorter pulses are expected).

Experiments are performed in the IR user labs, as shown in the upper left corner of the sketch in Fig. 1.

The optical tables and the (remotely controlled) beam distribution system are indicated.

A lot of ancillary equipment is provided, most importantly a number of table-top optical sources (in various wavelength ranges) based on femtosecond Ti:Sapphire lasers,

which are synchronized with the FEL to better than a picosecond.

One of the user labs is commissioned for handling of radioactive substances, thus allowing for IR spectroscopy on radioactive samples.

Experiments which have been performed so far include: • Imaging/mapping of thin molecular films on surfaces by polarization-modulation IR reflection-absorption spectroscopy.

• Scattering scanning-near-field optical microscopy (SNOM) on ferroelectric-crystal surfaces.

• Pump-probe spectroscopy on semiconductor quantum structures.

What has been seen in all types of experiments so far is the unprecedented signal-to-noise ratio made possible by working in cw mode.

As an example we present in Fig. 3 a pump-probe signal of a semiconductor superlattice, which shows the bleaching of the interminiband absorption and subsequent electron thermalization and cooling [3].

In the near future the IR beam of the

rossendorf.de/HLD), which will provide magnetic-field pulses in the 60-100 Tesla range with 1000-10 ms pulse duration, thus opening the way for many new spectroscopic investigations, in particular in solid state physics.

The work which has been briefly summarized here has of course been a large undertaking of many people, whose dedicated efforts over many years are gratefully acknowledged.

References 1. P. Michel et al., in Proceedings of the 26th International FEL Conference, Trieste, 2004 (http://accelconf.web.cern.ch/AccelConf/f 04/papers/MOAIS04/MOAIS04.pdf) 2. U. Lehnert, P. Michel, W. Seidel, D. Stehr, J. Teichert, D. Wohlfarth, and R. Wünsch, Proceedings of the 27th International FEL Conference,

Stanford,

2005.å

(http://accelconf.web.cern.ch/AccelConf/f 05/papers/TUPP030.pdf) 3. D. Stehr, S. Winnerl, M. Helm, T. Dekorsy, T. Roch, and G. Strasser, Appl. Phys. Lett. 88, 151108 (2006).

FOR INFORMATION ON: Conference Announcements and Advertising for Europe and US, rates and inserts can be found at: www.cnr.it/neutronielucedisincrotrone

Pina Casella Tel. +39 06 72594560 e-mail: pina.casella@roma2.infn.it

FELs will be guided into the recently opened, nearby high-magnetic-field laboratory Dresden (HLD; www.fz-

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NEWS AND MEETING REPORTS

The ILL Millennium Symposium and European User Meeting (27-29 March) Five years ago the ILL convened the first Millennium Symposium to launch an ambitious modernisation programme of instruments and infrastructure called the ILL Millennium Programme. Five years of hard work by the ILL staff in all divisions, with enthusiastic support from our users, have further expanded the ILL’s suite of unique world’s-best instruments and yielded many-fold gains in efficiency and quality on several existing instruments. The Second Symposium with our users was held at the end of April to demonstrate the achievements of the Millennium Programme to date, and to boost the ILL’s ambitious plans for the coming decade.

The scientific programme included a combination of presentations of scientific results and frontier achievements in methods and neutron techniques, mostly by our users.

ILL scientists and engineerw also presented their ambitious plans for instrument developments and analysis techniques in the coming decade. Seven parallel sessions allowed intense discussion and feed-

back from the users in smaller groups. No holds were barred, yet all criticism will be considered in depth. The hectic schedule of 21 plenary talks, 49 talks in parallel sessions, 3 summary talks, and 73 posters, many on instrument developments at other neutron facilities, ensured lively discussion at the coffee breaks. The poster A document “Perspectives and Opportunities for ILL”, which will include projects for instruments, infrastructure and user interface facilities as well as renewal plans of key components of the reactor, moderators and neutron guides, is in preparation.

Feedback from the users, expressed during the Symposium, or on the Symposium web site, will guide these objectives.

The Second Millennium Symposium was also an opportunity to renew old acquaintances. Prof Dirk Dubbers, the father of the Millennium Programme, was the honorary chairman. We were also honoured by the sprightly presence of two other former ILL Directors, Bernard Jacrot and Peter Schofield, as well

as the future British Director, Andrew Harrison. Waning but not gone yet Colin Carlile enthralled us all with a stellar after-dinner speech, but finally did not pass on his coveted joke book. Perhaps it will resurface in Swedish? Victim of the only technical hiccough of the Symposium, a talk with fewer figures than he expected, Werner Kuhs was justly rewarded for his perseverance by the gift of a rare signed local publication.

The extended family of the Diffraction Group may however choose a less conspicuous table at the Third Millennium Symposium.

Often hidden behind the scenes, Barbara Standke and Claire Gubian welcomed all attendees, Sylvie Perroux weaved the web site, Paul Henry and Peter Fouquet wielded Allen keys, the staff of SI provided excellent on-site computer facilities, Francoise Vauquois gave a hand in the communication of the event and Serge Claisse caught the magic moments seen here.

1st International Workshop on the Dynamics of Molecules and Materials (31 January to 2 February 2007, Grenoble) The 1st International Workshop on the Dynamics of Molecules and Materials will be held in Grenoble at the ILL/ESRF site from Wednesday 31 January to Friday 2 February 2007.

The Workshop will bring together

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scientists studying complex materials and molecular systems that are typically only available in polycrystalline form. Insight into the intrinsic dynamical properties of these materials can be obtained either by an in-

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tegrated dynamic response as a phonon density of states or through selected individual phonons.

The principal aim of the Workshop is an exchange of results and ideas from different techniques and meth-

NEWS AND MEETING REPORTS

ods, both experimental and computational. We want to receive input from the user community in order to identify future trends, the most informative experiments to be done, as well as needs for modelling and new

instrumentation.

The Workshop is organized jointly by the ILL and the ISIS Facility and it will be held at the premises of the European Synchrotron Radiation Facility at the common ILL-ESRF site

in Grenoble.

Further information can be obtained from the website http://www.ill.fr/Events/DMM/

ILL SOFT MATTER USER MEETING First announcement INSTITUT LAUE-LANGEVIN Grenoble, France (22-24 November 2006) This is the first announcement for an ILL Soft Matter User Meeting organized by the Institut Laue-Langevin.

The workshop should gather scientists whose interest is to apply elastic and inelastic neutron scattering to their own soft matter research.

It will offer an opportunity to present and to discuss recent neutron scattering research in this field and to identify the needs of the soft matter ILL-user community.

In particular, it is proposed to address the questions of on-site characterization and preparation of samples, complementary methods and optimization of the use of beam-time.

In view of the possible creation of a Partnership for Soft Condensed Matter on the ILL-ESRF site this workshop will give the unique opportunity to raise user interests concerning structure, scientific orientation and equipment in an early stage. Neutron scattering techniques are powerful tools for the characterization of the structure and dynamics of softmatter systems. The advantage of neutrons in soft-matter studies derives mainly from the fact that neutrons are strongly scattered by light atoms and the scattering power can

vary for different isotopes of the same atom. This allows the use of contrast variation for highlighting the interesting parts of the systems with a fraction of nanometer resolution. Concerning dynamics the extraordinarily high incoherent scattering cross section of hydrogen permits the exploration of the time dependent self correlation of soft matter. Other advantages include the possibility of studying buried systems, to apply external stimuli in non-equilibium experiments such as Rheo-SANS , do in-situ measurements, and the fact that neutron beams are non-destructive.

Because of their fragile nature, softmatter samples are often prepared on site just before a neutron experiment and in many cases their quality needs to be pre-assessed for an efficient use of neutron beam-time.

Soft matter scientists are invited to participate in this workshop and to present their work in the fields of polymers, colloids and interface science, involving both neutrons and complementary techniques. Ample time will be reserved for discussions in order to define the needs of the community concerning an onsite facility for sample preparation/

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deuteration and pre- as well as postcharacterization.

Abstracts can be submitted for both oral and poster presentations at the workshop web-site: http://www.ill.fr/SOFTILL2006 <http://www.ill.fr/softill2006>.

Deadline for abstract submission is July 19th 2006. Registration is free.

Accommodation in the guest-house will be offered limited to the available places and on a first come-first served basis.

For any further information you can contact us at softill2006@ill.fr <mailto:softill2006@ill.fr> G. Fragneto

Chair: Stefan Egelhaaf Advisory Committee: Christiane Alba-Simionesco, Robert McGreevy, Richard Jones, Dieter Richter, Peter Schurtenberger Local Organizing Committee: Trevor Forsyth, Giovanna Fragneto, Bernhard Frick, Isabelle Grillo, Peter Lindner, Peter Timmins, Christian Vettier

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NEWS AND MEETING REPORTS

e.VERDI Project VLAD INAUGURATION (12 December 2005)

Prof. Giuseppe Gorini (Università degli Studi di Milano Bicocca, Italy) illustrates the principles of operation of the VLAD bank.

The inauguration reception of the VLAD bank, hosted by Andrew Taylor, seen here next to Prof.

Carla Andreani (Università degli Studi di Roma Tor Vergata, Italy). On the front row, left to right, Dr Uschi Steigenberger (ISIS), Prof. Giuseppe Gorini (Università degli Studi di Milano Bicocca, Italy), Dr. Andrew Taylor (ISIS), Prof. Carla Andreani (Università degli Studi di Roma Tor Vergata, Italy), Prof. Marco Zoppi (CNR, Italy) and Prof. George Reiter (University of Huston, USA)

The Very Low Angle Detector (VLAD) bank has been installed recently on the VESUVIO spectrometer, at the ISIS facility, UK. VLAD was inaugurated on the 12th December 2005 by Dr Andrew Taylor, the Head of Facility, with a reception for the scientists, engineers and techni-

Andrew Taylor, Carla Andreani and Colin Windsor celebrate the coming of age of the n,γresonance detection technique at the VLAD inauguration, December 2005 at ISIS .

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cians involved in the work.

VESUVIO–an inverted geometry time-of-flight neutron spectrometer –was originally designed for momentum distribution investigations of light nuclei in condensed matter.

Where the application of the deep inelastic neutron scattering technique, in the Compton regime, is exploited. (Here, high energy transfers, >1eV, and high momentum transfers, >20 Å-1, are required.)

Recently, the experimental setup of VESUVIO underwent a major upgrade within the EU funded project, eVERDI, involving the Università degli Studi di Roma Tor Vergata, Università degli Studi di Milano Bicocca, University of Kent at Canterbury and the ISIS Facility.

The project included, among other items, the installation of the VLAD

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bank, covering the angular range of 1°<2 <5°. This allows neutron scattering with high energy transfers but now at low momentum transfers (q < 10 Å-1). It uses a novel neutron detection technique (n,γ-resonance detection) which was developed within the eVERDI project (VESUVIO upgrade). Here, gamma detectors record the photon cascade following the resonant capture of the scattered neutrons by a thin 238U foil.

The γ-detector consists of a cerium doped yttrium aluminium perovskite (YAP) scintillator coupled to a photomultiplier tube.

With the current setup the accessibility of a yet unexplored dynamical range of inelastic neutron spectroscopy at eV energies has been achieved, facilitating the investigation of electronic transitions in rare earth metals and compounds, vibrational levels in insulators, semiconductors, and magnetic materials.

John Tomkinson ISIS Neutron Source

CALL FOR PROPOSAL

Call for proposals for

Call for proposals for

Neutron Sources

Synchrotron Radiation Sources

http://neutron.neutron-eu.net/n_about/n_where/europe

http://www.lightsources.org/cms/?pid=1000336#byfacility

BENSC

ALS

Deadlines for proposal submission: 15th September 2006 www.hmi.de/bensc www.hmi.de/bensc/user-info/call-bensc_en.html

Deadlines for proposal submission: 5th June 2006 www-als.lbl.gov/als/quickguide/independinvest.html

BNC

Deadlines for proposal submission: 14 July 2006 www.aps.anl.gov/Users/Scientific_Access/General_User/ GUP_Calendar.

Deadlines for proposal submission: 15th October 2006 www.bnc.hu www.bnchu/modules.php?name=News&file=article&sid=1 05 http://nfdfn.jinr.ru

FRJ-2 Deadlines for proposal submission: Anytime during 2006 www.fz-juelich.de/iff/wns/

FRM-II Deadlines for proposal submission: Anytime during 2006 wwwnew.frm2.tum.de/en.html

GeNF Deadline for proposal submission: Anytime during 2006 www.gkss.de/index_e_js.hmtl

ILL Deadlines for proposal submission: 19 September 2006 www.ill.fr

IRI

APS

BESSY Deadlines for proposal submission: 15th August 2006 www.bessy.de/boat/

CHESS Deadlines for proposal submission: 31st October 2006 www.chess.cornell.edu/prposals/index.htm

CNM Deadlines for proposal submission: 14th July 2006 http://nano.anl.gov/users/index.html

DARESBURY Deadlines for proposal submission: 1st November 2006 www.srs.ac.uk/srs/userSR/user_access2.html

ELETTRA Deadlines for proposal submission: 31st August 2006 www.elettra.trieste.it/UserOffice/index.php?n=Main.Appli cationForBeamtime

Deadlines for proposal submission: Anytime during 2006 www.rid.tudelft.nl/live/pagina.jsp?id=b15d7df9-7928441e-b45d-6ecce78d6b0e&lang=en

ESRF

ISIS

FELIX

Deadlines for proposal submission: 15th March 2006 www.isis.rl.ac.uk

Deadlines for proposal submission: 1st December 2006 www.rijnh.nl/molecular-and-laserphysics/felix/n4/f1234.htm

LLB-ORPHEE-SACLAY Deadlines for proposal submission: 1 October 2006 www-llb.cea.fr

NPL Deadlines for proposal submission: 15th September 2006 www.omega.ujf.cas.cz/CFANR/access.html

SINQ Deadlines for proposal submission: 15th Novembre 2006 http://sinq.web.psi.ch/

Deadlines for proposal submission: 1st September 2006 www.esrf.fr

HASYLAB Deadlines for proposal submission: 1st September 2006 www.hasylab.desy.de/user_infos/projects/3_deadlines.htm

MAX-LAB Deadline for proposal submission: July 2006 www.maxlab.lu.se

NSLS Deadlines for proposal submission: 31st September 2006 www.nls.bnl.gov/

SLS Deadlines for proposal submission: 15th September and 15th October 2006 http://sls.web.psi.ch/view.php/users/experiments/propo sals/opencalls/index.html

SRC Deadlines for proposal submission: 1st August 2006

SSRL Deadlines for proposal submission: 1st July, 14th August, 28th August, 1st December 2006 www.ssrl.slac.stanford.edu/users/user_admin/deadlines .html

Vol. 11 n. 2 July 2006

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CALENDAR

July 6 – 8, 2006

HYOGO, JAPAN

SRPS3 - Synchrotron Radiation in Polymer Science III Lecture Hall in Public Relations Center http://www.spring8.or.jp/en/users/meeting/2006/srps3

July 9 - 13, 2006

KYOTO, JAPAN

SAS2006 Kyoto – 13th International Conference on Small-Angle Scattering Kyoto International Conference Hall http://sas2006.scphys.kyoto-u.ac.jp/

July 9 – 14, 2006

ZÜRICH, SWITZERLAND

Nanoanalysis - CEAC Summer Workshop HG E 1.1, ETH Zentrum, 8092 Zürich http://www.ceac.ethz.ch/Ceac/Workshop.html

July 11 – 12, 2006

CHILTON, UK

PhotoEmission Electron Microscopy (PEEM) Workshop Diamond Light Source http://www.diamond.ac.uk/News/LatestEvents/PEEMw orkshop.htm

July 12 – 18, 2006

MANCHESTER, UK

EPS-HEP2007 - European Physical Society Conference on High Energy Physics http://www.hep.man.ac.uk/HEP2007/

July 14 2006

GARCHING, GERMANY

Workshop Neutrons for Geoscience Faculty for Mechanical Engineering http://www.new.frm2.tum.de/en/events/ konferenzen.html

July 16 – 20, 2006

TAIPEI, TAIWAN

YEREVAN, ARMENIA

Brilliant Light Facilities and Research in Life and Material Sciences NATO Advanced Research Workshop (ARW) http://www.candle.am/ARW06/

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ACA 2006 - The 2006 Meeting of the American Crystallographic Association http://www.xray.chem.ufl.edu/aca2006/index.html

July 23 – 26, 2006

PILANESBERG, SOUTH AFRICA

2nd International Conference on Diamond for Modern Light Sources Kwa Maritane Bush Lodge http://hermes.wits.ac.za/www/Conferences/diamond/in dex.htm

July 30 – Aug 2, 2006

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CHICAGO, IL, USA

SRMS-5 - Fifth International Conference on Synchrotron Radiation in Materials Sciente The Drake Hotel http://www.aps.anl.gov/News/Conferences/2006/SRMS /index.html

Aug 5 - 9, 2006

SAN DIEGO, CA, USA

20th Annual Symposium of The Protein Society e-mail: cyablonski@proteinsociety.org http://www.proteinsociety.org/pages/page00g.htm

Aug 19 - 26, 2006

ZUOZ, SWITZERLAND

4th PSI Summer School on Condensed Matter Research: ‘Neutron, X-ray and Muon studies of nano scale structures’ Lyceum Alpinum e-mail: renate.bercher@psi.ch http://num.web.psi.ch/zuoz2006/

Aug 27 – Sept 1, 2006

BERLIN, GERMANY

FEL2006 - 28th International Free Electron Laser Conference e-mail: fel2006@bessy.de http://www.bessy.de/fel2006

Aug 28 – Sept 1, 2006

9SXNS - Ninth International Conference on Surface X-Ray and Neutron Scattering http://web11.nsrrc.org.tw/9sxns/

July 17 – 21, 2006

HONOLULU, HAWAII, USA

STANFORD, CA, USA

XAFS13 - 13th International Conference on X-ray Absorption Fine Structure Stanford University campus. http://www-ssrl.slac.stanford.edu/xafs13/

July 10 – 11, 2006

July 22 – 27, 2006

FOZ DO IGUAÇU, BRAZIL

ICESS 10 International Conference on Electronic Spectroscopy and Structure http://www.lnls.br/icess10

Aug 31 – Sept 9, 2006

JACA, SPAIN

International Summer School on “Neutron Techniques in Molecular Magnetism” e-mail: magmanet@unizar.es http://magmanet.unizar.es/

CALENDAR

Sept 4 – 6, 2006

RIO DE JANEIRO, BRAZIL

SCASM - International Symposium: Scattering, Coincidence and Absorption Studies of Molecules Federal University http://server2.iq.ufrj.br/~scasm2006

Sept 4 - 8, 2006

PARIS, FRANCE

ECOSS-24 - 24th European Conference on Surface Science http://www.iuvsta.org/ecoss.html

Sept 10 - 13, 2006

JACA, SPAIN

III Meeting of the Spanish Society of Neutron Techniques http://www.unizar.es/magmanet/summerschool/

Sept 10 - 14, 2006

SAN FRANCISCO, CA, USA

232nd American Chemical Society Meeting Moscone Center http://www.chemistry.org/portal/a/c/s/1/acsdisplay.ht ml?DOC=meetings\sanfrancisco2006\home.html

Sept 12 – 13, 2006

CHILTON, OXFORDSHIRE, UK

Diamond Light Source Users’ Meeting Diamond Light Source, Harwell Science and Innovation Campus http://www.diamond.ac.uk/ForUsers/SRUser06/ default.htm

Sept 13 – 15, 2006

BREMEN, GERMANY

7th European Conference on Residual Stresses (ECRS7) AWT E-mail: awt.ev@t-online.de http://www.ecrs7.de/

Sept 14 – 15, 2006

GRENOBLE, FRANCE

Theoretical Concepts on Magnetism in Solids Symposium ESRF http://www.esrf.fr/NewsAndEvents/Conferences/ PaoloCarraSymposium

Sept 17 – 21, 2006

RATHEN, GERMANY

NSS4 - 4th International Workshop on Nanoscale Spectroscopy and Nanotechnology e-mail: NSS4@bessy.dehttp://www.bessy.de/cms.php?idcat=184&c hangelang=5

Sept 18 - 22, 2006

SHANGAI, P.R. China

IRMMW/ THz 2005 - Joint 31st International Conference on Infrared and Millimeter Waves and 14th International Conference on Terahertz Electronics Hotel Equatorial Shanghai e-mail: Irmmw-thz2006@mail.sitp.ac.cn Irmmwthz2006@yahoo.com.cn http://www.sitp.ac.cn/irmmw-thz2006

Sept 19 - 22, 2006

KARLSRUHE, GERMANY

XTOP 2006 - 8th Biennial Conference on High Resolution X-Ray Diffraction and Imaging Steigenberger Hotel Badischer Hof http://xtop2006.fzk.de

Sept 19 - 22, 2006

BERLIN, GERMANY

Polarised Neutron School Leibniz-Saal http://www.hmi.de/bensc/pncmi2006

Sept 25 - 27, 2006

LUND, SWEDEN

FASM 19th Users’ Meeting at MAX-lab Hotel Scandic Star. http://www2.maxlab.lu.se/meeting/um/index.jsp

Sept 25 - 28, 2006

BERLIN, GERMANY

Polarised Neutrons in Condensed Matter Investigations, PNCMI 2006 Leibniz-Saal e-mail: pncmi@hmi.de http://www.hmi.de/bensc/pncmi2006

Sept 25 – Oct 6, 2006

S. MARGHERITA DI PULA, ITALY

VIII International School of Neutron Scattering “Francesco Paolo Ricci” - Neutron Scattering From Magnetic Systems Hotel Flamingo http://www.fis.uniroma3.it/sns_fpr/

Sept 27 – 29, 2006

BERLIN, GERMANY

SR2A - Synchrotron Radiation in Arts and Archaeology Workshop Berlin Adlershof http://www.bessy.de/cms.php?idcat=176

Vol. 11 n. 2 July 2006

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CALENDAR

Sept 28 – 29, 2006

VILLIGEN, PSI, SWITZERLAND

SLS Users’ Meeting Paul Scherrer Institute e-mail: slsuo@psi.ch http://sls.web.psi.ch/view.php/users/affairs/umeetings/U mee2006/index.html

Sept 29 - 30, 2006

BERLIN, GERMANY

The 3rd workshop on Inelastic Neutron Spectrometers 2006 SpreePalais am Dom http://www.hmi.de/bensc/wins2006/main.html

Oct 2 - 4, 2006

VILLIGEN, SWITZERLAND

International Workshop on Applications of Advanced Monte Carlo Simulations in Neutron Scattering Paul Scherrer Institute http://lns00.psi.ch/mcworkshop/

Oct 3 – 4, 2006

HSINCHU, TAIWAN

NSRRC Users’ Meeting http://users.nsrrc.org.tw/meeting/index-en.htm

Oct 4 - 6, 2006

HAMBURG, GERMANY

German Conference for Research with Synchrotron Radiation, Neutrons and Ion Beams at Large Facilities 2006 Hamburg University http://www.sni2006.de/

Oct 9 - 10, 2006

KARLSRUHE, GERMANY

ANKA Users’ Meeting Forschungszentrum http://ankaweb.fzk.de/conferences/users-meeting-2006/

Oct 23 - 25, 2006

OAK RIDGE, USA

Workshop on Imaging and Neutrons (IAN2006) Oak Ridge National Laboratory http://www.sns.gov/workshops/ian2006/

Nov 6 – 10, 2006

BARILOCHE, ARGENTINA

13th International Conference on Solid Films and Surfaces Panamericano Hotel http://www.cab.cnea.gov.ar/icsfs-13/

Nov 22 – 24, 2006

GRENOBLE, FRANCE

ILL Soft Matter User Meeting ILL http://www.ill.fr/softill2006/ILL%20soft%20Matter%20User %20Meeting/Homepage.html

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Nov 24 – 25, 2006

KEK, TSUKUBA, JAPAN

AOF2006 - First Asian/Oceanic Forum for Synchrotron Radiation Research Building No.3 Seminar Hall http://pfwww.kek.jp/AOF2006/index.html

Nov 27 – 29, 2006

CAIRO, EGYPT

5th SESAME Users’ Meeting http://www.cu.edu.eg/science/sesame/Tentative_Progra m.htm

Dec 7 - 8, 2006

SAN FRANCISCO, CA, USA

Neutron Scattering applied to Earth Sciences Fall 2006 American Geophysical Union http://www.minsocam.org/MSA/SC/ Neutron_descrptn.html

Dec 13 - 15, 2006

GRENOBLE, FRANCE

Dynamics of Molecules and Materials ILL http://www.ill.fr/Events/DMM/

FACILITIES

NEUTRON SOURCES NEUTRON SCATTERING WWW SERVERS IN THE WORLD (http://neutron.neutron-eu.net/n_news/n_calendar_of_events)

BENSC Berlin Neutron Scattering Center Hahn-Meitner-Institut Glienicker Strasse 100 D-14109 Berlin, Germany Tel: ~49/30/8062-2778; Fax: ~49/30/8062-2523 E-mail: bensc@hmi.de http://www.hmi.de/bensc/index_en.html Budapest Neutron Centre Budapest Research Reactor Type: Reactor. Flux: 2.0 x 1014 n/cm2/s Address for application forms: Dr. Borbely Sรกndor KFKI Building 10, 1525 Budapest - Pf 49, Hungary E-mail: Borbely@power.szfki.kfki.hu http://www.iki.kfki.hu/nuclear CNF Canadian Neutron Beam Centre National Research Council of Canada Building 459, Station 18 Chalk River Laboratories Chalk River, Ontario CANADA K0J 1J0 Tel: 1- (888) 243-2634 (toll free) / 1- (613) 584-8811 ext. 3973 Fax: 1- (613) 584-4040 http://cnf-ccn.gc.ca/home.html FRG-1 Geesthacht (D) Type: Swimming Pool Cold Neutron Source.

Flux: 8.7 x 1013 n/cm2/s Address for application forms and informations: Reinhard Kampmann, Institute for Materials Science, Div. Wfn-Neutronscattering, GKSS, Research Centre, 21502 Geesthacht, Germany Tel: +49 (0)4152 87 1316/2503; Fax: +49 (0)4152 87 1338 E-mail: reinhard.kampmann@gkss.de http://www.gkss.de HFIR Oak Ridge National Lab. Oak Ridge, USA Tel: (865)574-5231; Fax: (865)576-7747 E-mail: ns_user@ornl.gov http://neutrons.ornl.gov/ HMI Berlin BER-II (D) Facility: BER II, BENSC Type: Swimming Pool Reactor. Flux: 2 x 1014 n/cm2/s Address for application forms: Dr. Rainer Michaelsen, BENSC, Scientific Secretary, Hahn-Meitner-Institut,

Glienicker Str 100, 14109 Berlin, Germany Tel: +49 30 8062 2304/3043; Fax: +49 30 8062 2523/2181 E-mail: michaelsen@hmi.de http://www.hmi.de/bensc IBR2 Fast Pulsed Reactor Dubna (RU) Type: Pulsed Reactor.

Flux: 3 x 1016 (thermal n in core) Address for application forms: Dr. Vadim Sikolenko, Frank Laboratory of Neutron Physics Joint Institute for Nuclear Research 141980 Dubna, Moscow Region, Russia.

Tel: +7 09621 65096; Fax: +7 09621 65882 E-mail: sikolen@nf.jinr.dubna.su http://nfdfn.jinr.ru/flnph/ibr2.html ILL Grenoble (F) Type: 58MW High Flux Reactor.

Flux: 1.5 x 1015 n/cm2/s Scientific Coordinator Dr. G. Cicognani, ILL, BP 156, 38042 Grenoble Cedex 9, France Tel: +33 4 7620 7179; Fax: +33 4 76483906 E-mail: cico@ill.fr and sco@ill.fr http://www.ill.fr IPNS Intense Pulsed Neutron at Argonne (USA) for proposal submission by e-mail send to cpeters@anl.gov or mail/fax to: IPNS Scientific Secretary, Building 360 Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439-4814, USA Phone: 630/252-7820; Fax: 630/252-7722 http://www.pns.anl.gov/ ISIS Didcot (UK) Type: Pulsed Spallation Source.

Flux: 2.5 x 1016 n fast/s Address for application forms: ISIS Users Liaison Office, Building R3, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX Tel: +44 (0) 1235 445592; Fax: +44 (0) 1235 445103 E-mail: uls@isis.rl.ac.uk http://www.isis.rl.ac.uk JAERI (J) Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Ibaraki-ken 319-11, Japan.

Jun-ichi Suzuki (JAERI);

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FACILITIES

250 68 Rez - Czech Republic Tel: +420 2 20941177 / 66173428; Fax: +420 2 20941155 E-mail: krz@ujv.cz and brv@nri.cz http://www.nri.cz

Yuji Ito (ISSP, Univ. of Tokyo); Fax: +81 292 82 59227; Telex: JAERIJ24596 http://www.ndc.tokai.jaeri.go.jp/ JEEP-II Kjeller (N) Type: D2O moderated 3.5% enriched UO2 fuel.

Flux: 2 x 1013 n/cm2/s Address for application forms: Institutt for Energiteknikk K.H. Bendiksen, Managing Director Box 40, 2007 Kjeller, Norway Tel: +47 63 806000, 806275; Fax: +47 63 816356 E-mail: kjell.bendiksen@ife.no http://www.ife.no KENS Institute of Materials Structure Sciente High Energy Accelerator research Organisation 1-1 Oho, Tsukuba-shi, Ibaraki-ken,?305-0801, JAPAN E-mail: kens-pac@nml.kek.jp http://neutron-www.kek.jp/index_e.html KUR Kyoto University Research Reactor Institute, Kumatori-cho Sennan-gun, Osaka 590-0494,Japan Tel::+81-72-451-2300 Fax:+81-72-451-2600 http://www.rri.kyoto-u.ac.jp/en/

LLB Orphée Saclay (F) Type: Reactor. Flux: 3.0 x 1014 n/cm2/s Laboratoire Léon Brillouin (CEA-CNRS) E-mail: experience@llb.saclay.cea.fr http://www-llb.cea.fr/index_e.html NIST Center for Neutron Research (USA) National Institute of Standards and Technology 100 Bureau Drive, MS 8560 Gaithersburg, MD 20899-8560 Patrick Gallagher, Director tel: (301) 975-6210 fax: (301) 869-4770 E-email: pgallagher@nist.gov http://www.ncnr.nist.gov/call/current_call.html NRI Rez (CZ) Type: 10 MW research reactor.

Address for informations: Zdenek Kriz, Scientif Secretary Nuclear Research Institute Rez plc,

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PSI-SINQ Villigen (CH) Type: Steady spallation source.

Flux: 2.0 x 1014 n/cm2/s Contact address: Paul Scherrer Institut User Office, CH-5232 Villigen PSI - Switzerland Tel: +41 56 310 4666; Fax: +41 56 310 3294 E-mail: sinq@psi.ch http://sinq.web.psi.ch RID Reactor Institute Delft (NL) Type: 2MW light water swimming pool.

Flux: 1.5 x 1013 n/cm2/s Address for application forms: Dr. M. Blaauw, Head of Facilities and Services Dept.

Reactor Institute Delft, Faculty of Applied Sciences Delft University of Technology, Mekelweg 15 2629 JB Delft, The Netherlands Tel: +31-15-2783528 Fax: +31-15-2788303 E-mail: m.blaauw@tudelft.nl http://www.rid.tudelft.nl

LANSCE Los Alamos Neutron Sciente Center TA-53, Building 1, MS H831 Los Alamos National Lab, Los Alamos, USA 505-665-8122 E-mail: tichavez@lanl.gov http://www.lansce.lanl.gov/index.html

NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE

NRU Chalk River Laboratories The peak thermal flux 3x1014 cm-2 sec-1 Neutron Program for Materials Research National Research Council Canada Building 459, Station 18 Chalk River Laboratories Chalk River, Ontario - Canada K0J 1J0 Phone: 1 - (888) 243-2634 (toll free) Phone: 1 - (613) 584-8811 ext. 3973 Fax: 1- (613) 584-4040 http://neutron.nrc-cnrc.gc.ca/home.html

Vol. 11 n. 2 July 2006

SPALLATION NEUTRON SOURCE, ORNL (USA) Address for information: A. E. Ekkebus, Spallation Neutron Source, Oak Ridge National Laboratory One Bethel Valley Road, Bldg 8600 P. O. Box 2008, MS 6460 Oak Ridge, TN 37831 - 6460 Tel: 089 289 14701; Fax: 089 289 14666 http://www.sns.gov/ TU Munich FRM, FRM-2 (D) Type: Compact 20 MW reactor.

Flux: 8 x 1014 n/cm2/s Address for information: Prof. Winfried Petry, FRM-II Lichtenbergstrasse 1 - 85747 Garching Tel: 089 289 14701; Fax: 089 289 14666 E-mail: wpetry@frm2.tum.de http://www.frm2.tu-muenchen.de

FACILITIES

SYNCHROTRON RADIATION SOURCES SYNCHROTRON SOURCES WWW SERVERS IN THE WORLD (http://www.esrf.fr/navigate/synchrotrons.html)

ALBA - Synchrotron Light Facility CELLS - ALBA, Edifici Ciències. C-3 central. Campus UAB Campus Universitari de Bellaterra. Universitat Autònoma de Barcelona 08193 Bellaterra, Barcelona, Spain tel: +34 93 592 43 00 ?- fax: +34 93 592 43 01 http://www.cells.es/ ALS Advanced Light Source Berkeley Lab, 1 Cyclotron Rd, MS6R2100, Berkeley, CA 94720 tel: +1 510.486.7745 - fax: +1 510.486.4773 E-mail: alsuser@lbl.gov http://www-als.lbl.gov/ ANKA Forschungszentrum Karlsruhe Institut für Synchrotronstrahlung Hermann-von-Helmholtz-Platz 1, 76344 EggensteinLeopoldshafen, Germany tel: +49 (0)7247 / 82-6071 - fax: +49-(0)7247 / 82-6172 E-mail: info@fzk.de http://hikwww1.fzk.de/iss/ APS Advanced Photon Source Argonne Nat. Lab. 9700 S. Cass Avenue, Argonne, Il 60439, USA tel: (630) 252-2000 - fax: +1 708 252 3222 http://www.aps.anl.gov

BSRF Beijing Synchrotron Radiation Facility BEPC National Laboratory, Institute of High Energy Physics, Chinese Academy of Sciences P.O.Box 918, Beijing 100039, P.R. China tel: +86-10-68235125 - fax: +86-10-68222013 E-mail: houbz@mail.ihep.ac.cn http://www.ihep.ac.cn/bsrf/english/main/main.htm CANDLE Center for the Advancement of Natural Discoveries using Light Emission Acharyan 31 ?375040, Yerevan, Armenia tel/fax: +374-1-629806 E-mail: baghiryan@asls.candle.am http://www.candle.am/index.html CAMD Center Advanced Microstructures & Devices CAMD/LSU 6980 Jefferson Hwy., Baton Rouge, LA 70806, USA tel: +1 (225) 578-8887 - fax : +1 (225) 578-6954 E-mail: leeann@lsu.edu http://www.camd.lsu.edu/ CHESS Cornell High Energy Synchrotron Source Cornell High Energy Synchrotron Source 200L Wilson Lab, Rt. 366 & Pine Tree Road, Ithaca, NY 14853, USA Tel: +1 (607) 255-7163, +1 (607) 255-9001 E-mail: useradmin@mail.chess.cornell.edu http://www.tn.cornell.edu/

ASTRID ISA, Univ. of Aarhus, Ny Munkegade, DK-8000 Aarhus, Denmark tel: +45 61 28899 - fax: +45 61 20740 http://www.aau.dk/uk/nat/isa

CLS Canadian Light Source Canadian Light Source Inc., University of Saskatchewan 101, Perimeter Road Saskatoon, SK., Canada. S7N 0X4 tel: (306) 657-3500 - fax: (306) 657-3535 E-mail: clsuo@lightsource.ca http://www.lightsource.ca

AS Australian Synchrotron Level 17, 80 Collins St_Melbourne VIC 3000_Australia tel: +61 3 9655 3315 - fax: +61 3 9655 8666 E-mail: contact.us@synchrotron.vic.gov.au http://www.synchrotron.vic.gov.au

DAFNE Light INFN – LNF Via Enrico Fermi, 40, I-00044 Frascati (Rome), Italy fax: +39 6 94032597 www.lnf.infn.it/esperimenti/sr_dafne_light/

BESSY Berliner Elektronenspeicherring Gessellschaft.für Synchrotronstrahlung BESSY GmbH, Albert-Einstein-Str.15, 12489 Berlin, Germany tel +49 (0)30 6392-2999 - fax: +49 (0)30 6392-2990 E-mail: info@bessy.de http://www.bessy.de

DELSY Dubna ELectron SYnchrotron JINR Joliot-Curie 6, 141980 Dubna, Moscow region, Russia tel: + 7 09621 65 059 - fax: + 7 09621 65 891 E-mail:_post@jinr.ru http://www.jinr.ru/delsy/

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FACILITIES

DELTA Dortmund Electron Test Accelerator - FELICITA I (FEL) Institut für Beschleunigerphysik und Synchrotronstrahlung, Universität Dortmund Maria-Goeppert-Mayer-Str. 2 44221 Dortmund, Germany fax: +49-(0)231-755-5383 www.delta.uni-dortmund.de/home_e.html

HASYLAB Hamburger Synchrotronstrahlungslabor - DORIS III, _PETRA II / III, FLASH DESY - HASYLAB Notkestrasse 85 22607 Hamburg, Germany tel: +49 40 / 8998-2304 - fax: +49 40 / 8998-2020 E-mail: hasylab@desy.de www-hasylab.desy.de/

DFELL Duke Free Electron Laser Laboratory Duke Free Electron Laser Laboratory PO Box 90319, Duke University Durham, North Carolina 27708-0319, USA tel: +1 (919) 660-2666 - fax: +1 (919) 660-2671 E-mail: beamtime@fel.duke.edu www.fel.duke.edu/

HSRC Hiroshima Synchrotron Radiation Center - HiSOR Hiroshima University 2-313 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan tel: +81 82 424 6293 fax: +81 82 424 6294 www.hsrc.hiroshima-u.ac.jp/index.html

Diamond Light Source Diamond Light Source Ltd Diamond House, Chilton, Didcot, OXON OX11 0DE, UK tel: +44 (0)1235 778000 fax: +44 (0)1235 778499 E-mail: dlsenquiries@diamond.ac.uk www.diamond.ac.uk/ ELETTRA Synchrotron Light Lab. Sincrotrone Trieste S.C.p.A Strada Statale 14 - Km 163,5 in AREA Science Park, 34012 Basovizza, Trieste, Italy tel: +39 40 37581 fax: +39 (040) 938-0902 E-mail: useroffice@elettra.trieste.it www.elettra.trieste.it ELSA Electron Stretcher Accelerator Physikalisches Institut der Universität Bonn Beschleunigeranlage ELSA, Nußallee 12, D-53115 Bonn, Germany tel: +49-228-735926 - fax +49-228-733620 E-Mail: roy@physik.uni-bonn.de www-elsa.physik.uni-bonn.de/elsa-facility_en.html ESRF European Synchrotron Radiation Lab. ESRF, 6 Rue Jules Horowitz, BP 220, 38043 Grenoble Cedex 9, FRANCE tel: +33 (0)4 7688 2000 fax: +33 (0)4 7688 2020 E mail: useroff@esrf.fr www.esrf.fr/ FELBE Free-Electron Lasers at the ELBE radiation source at the FZR/Dresden Bautzner Landstrasse 128 _01328 Dresden, Germany www.fz-rossendorf.de/pls/rois/Cms?pNid=471 FELIXFree Electron Laser for Infrared eXperiments FOM Institute for Plasma Physics ‘Rijnhuizen’ Edisonbaan, 14, 3439 MN Nieuwegein, The Netherlands P.O. Box 1207, 3430 BE Nieuwegein, The Netherlands tel: +31-30-6096999 fax: +31-30-6031204 E-mail: B.Redlich@rijnh.nl www.rijnh.nl/felix/

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iFEL Institute of Free Electron Laser, Graduate School of Engineering, Osaka University 2-9-5 Tsuda-Yamate, Hirakata, Osaka 573-0128, Japan tel: +81-(0)72-897-6410 www.fel.eng.osaka-u.ac.jp/english/index_e.html INDUS -1 / INDUS -2 Centre for Advanced Technology Department of Atomic Energy Government of India P.O : CAT Indore _M.P - 452 013 _India tel: +91-731-248-8003 _- fax: 91-731-248-8000 E-mail: rvn@cat.ernet.in http://www.ee.ualberta.ca/~naik/accind1.html IR FEL Research Center - FEL-SUT IR FEL Research Center, Research Institutes for Science and Technology The Tokyo University of Sciente, Yamazaki 2641, Noda, Chiba 278-8510, Japan tel: +81 4-7121-4290 - fax: +81 4-7121-4298 E-mail: felsut@rs.noda.sut.ac.jp www.rs.noda.sut.ac.jp/~felsut/english/index.htm ISA Institute for Storage Ring Facilities - ASTRID-1 ISA, University of Aarhus, Ny Munkegade, bygn. 520, DK-8000 Aarhus C, Denmark tel: +45 8942 3778 - fax: +45 8612 0740 E-mail: fyssp@phys.au.dk www.isa.au.dk/ ISI-800 Institute of Metal Physics National Academy of Sciences of Ukraine tel: +(380) 44 424-1005 - fax: +(380) 44 424-2561 E-mail:metall@imp.kiev.ua Jlab - Jefferson Lab FEL 12000 Jefferson Avenue, Newport News, Virginia 23606, USA tel: (757) 269-7767 www.jlab.org/FEL

FACILITIES

Kharkov Institute of Physics and Technology - Pulse Stretcher/Synchrotron Radiation National Science Center, KIPT, 1, Akademicheskaya St., Kharkov, 61108, Ukraine tel: 38 (057) 335-35-30 - fax: 38 (057) 335-16-88 www.kipt.kharkov.ua KEK Photon Factory Nat. Lab. for High Energy Physics, 1-1, Oho, Tsukuba-shi Ibaraki-ken, 305 Japan tel: +81 298 641171 - fax: +81 298 642801 www.kek.jp/ KSR Nuclear Science Research Facility - Accelerator Laboratory Gokasho,Uji, Kyoto 611 fax: +81-774-38-3289 wwwal.kuicr.kyoto-u.ac.jp/www/index-e.htmlx KSRS Kurchatov Synchrotron Radiation Source KSRS Siberia-1 / Siberia-2 Kurtchatov Institute 1, Kurtchatov Sq., Moscow 123182, Russia www.kiae.ru/eng/wel/alb/illus6.htm LCLS Linac Coherent Light Source Stanford Linear Accelerator Center (SLAC) 2575 Sand Hill Road, MS 18 ?Menlo Park, CA 94025 ?USA tel: +1 (650) 926-3191 - fax: +1 (650) 926-3600 E-mail: knotts@ssrl.slac.stanford.edu www-ssrl.slac.stanford.edu/lcls/

NSLS National Synchrotron Light Source NSLS User Administration Office Brookhaven National Laboratory, P.O. Box 5000, Bldg.

725B, Upton, NY 11973-5000, USA tel: +1 (631) 344-7976 - fax: +1 (631) 344-7206 E-mail: nslsuser@bnl.gov www.nsls.bnl.gov/ NSRL National Synchrotron Radiation Lab. University od Sciente and Technology China (USTC) Hefei, Anhui 230029, PR China tel +86-551-5132231,3602034 - fax: +86-551-5141078 E-mail: zdh@ustc.edu.cn www.nsrl.ustc.edu.cn/en/enhome.html NSRRC National Synchrotron Radiation Research Center National Synchrotron Radiation Research Center 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan, R.O.C. tel: +886-3-578-0281 - E-mail: user@nsrrc.org.tw www.nsrrc.org.tw/ NSSR Nagoya University Small Synchrotron Radiation Facility Nagoya University 4-9-1,Anagawa, Inage-ku, Chiba-shi, 263-8555 Japan tel: +81-(0)43-251-2111 http://nssr.xtal.nagoya-u.ac.jp PAL Pohang Accelerator Lab. San-31 Hyoja-dong Pohang, Kyungbuk 790-784, Korea tel: +82 562 792696 - fax: +82 562 794499 http://pal.postech.ac.kr/eng/index.html

LNLS Laboratorio Nacional de Luz Sincrotron Caixa Postal 6192, CEP 13084-971, Campinas, SP, Brazil tel: +55 (0) 19 3512-1010 - fax: +55 (0)19 3512-1004 E-mail: sau@lnls.br www.lnls.br/

PF Photon Factory KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan tel: +81 (0)-29-879-6009 - fax: +81 (0)-29-864-4402 E-mail: users.office2@post.kek.jp http://pfwww.kek.jp/

LURE Laboratoire pour l’utilisation du Rayonnement Electromagnétique Bât 209D Centre Universitaire Paris-Sud, B.P. 34 - 91898 Orsay Cedex, France tel: +33 (0)1 6446 8000 E-mail: useroffice@lure.u-psud.fr

RitS Ritsumeikan University SR Center - MIRRORCLE 6X/MIRRORCLE 20 Ritsumeikan University (RitS) SR Center, Biwako-Kusatsu Campus Noji Higashi 1-chome, 1-1 Kusatsu, 525-8577 Shiga-ken, Japan tel: +81 (0)77 561-2806 - fax: +81 (0)77 561-2859 E-mail:d11-www-adm@se.ritsumei.ac.jp www.ritsumei.ac.jp/acd/re/src/index.htm

MAX-Lab Box 118, University of Lund, S-22100 Lund, Sweden tel: +46-222 9872 - fax: +46-222 4710 www.maxlab.lu.se/ Medical Synchrotron Radiation Facility National Institute of Radiological Sciences (NIRS) 4-9-1, Anagawa, Inage-ku, Chiba-shi, 263-8555, Japan tel: +81-(0)43-251-2111 www.lightsources.org/cms/?pid=1000161

SESAME Synchrotron-light for Experimental Science and Applications in the Middle East E-mail: hhelal@mailer.eun.eg www.sesame.org.jo/ SLS Swiss Light Source Paul Scherrer Institut reception building, PSI West, CH-5232 Villigen PSI, Switzerland tel: +41 56 310 4666 - fax: +41 56 310 3294 E-mail slsuo@psi.ch http://sls.web.psi.ch

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FACILITIES

SPring-8 Japan Synchrotron Radiation Research Institute (JASRI) Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan tel: +81-(0) 791-58-0961 _- fax: +81-(0) 791-58-0965 E-mail: sp8jasri@spring8.or.jp www.spring8.or.jp/en/ SOLEIL Synchrotron SOLEIL L’Orme des Merisiers Saint-Aubin - BP 48 91192 GIF-sur-YVETTE CEDEX, FRANCE tel: +33 1 6935 9652 _- fax: +33 1 6935 9456 E-mail: frederique.fraissard@synchrotron-soleil.fr www.synchrotron-soleil.fr/anglais/index.html SOR-RING Institute for Solid State Physics S.R. Lab, Univ. of Tokyo, 3-2-1 Midori-cho Tanashi-shi, Tokyo 188, Japan tel: +81 424614131 - fax: +81 424615401 SRC Synchrotron Radiation Center Univ.of Wisconsin at Madison, 3731 Schneider Drive, Stoughton, WI 53589-3097 USA tel: +1 (608) 877-2000 - fax: +1 (608) 877-2001 www.src.wisc.edu SSLS Singapore Synchrotron Light Source –Helios II National University of Singapore (NUS) Singapore Synchrotron Light Source, National University of Singapore 5 Research Link, Singapore 117603, Singapore tel: (65) 6874-6568 - fax: (65) 6773-6734 http://ssls.nus.edu.sg/index.html SSRC Siberian Synchrotron Research Centre – VEPP3/VEPP4 Lavrentyev av. 11, Budker INP, Novosibirsk 630090, Russia tel: +7(3832)39-44-98 - fax: +7(3832)34-21-63 E-mail: G.N.Kulipanov@inp.nsk.su http://ssrc.inp.nsk.su/ SSRL Stanford Synchrotron Radiation Lab. Stanford Linear Accelerator Center, 2575 Sand Hill Road, Menlo Park, CA 94025, USA tel: +1 650-926-4000 - fax: +1 650-926-3600 E-mail: knotts@ssrl.slac.stanford.edu www-ssrl.slac.stanford.edu SRS Synchrotron Radiation Source CCLRC Daresbury Lab. Warrington, Cheshire, WA4 4AD, U.K. tel: +44 (0)1925 603223 - fax: +44 (0)1925 603174 E-mail: srs-ulo@dl.ac.uk www.srs.ac.uk/srs/

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Super SOR Light Source Kashiwa Campus, Univ. of Tokyo SRL Experimental Hall (Super SOR Project Office) 5-1-5 KashiwanoHa, Kashiwa-shi, Chiba 277-8581, Japan tel: +81 (0471) 36-3405 - fax: +81(0471) 34-6083 Kashiwa Campus, Univ. of Tokyo www.issp.u-tokyo.ac.jp/labs/sor/project/MENU.html SURF-II / SURF-III Synchrotron Ultraviolet Radiation Facility NIST, 100 Bureau Drive, Stop 3460 _Gaithersburg, MD 20899-3460, USA tel: +1 301 975 6478 http://physics.nist.gov/MajResFac/surf/surf.html TNK - F.V. Lukin Institute State Research Center of Russian Federation 103460, Moscow, Zelenograd tel. +7(095) 531-1306 / +7(095) 531-1603 - fax: +7(095) 531-4656 TSRF Tohoku Synchrotron Radiation Facilità - Laboratory of Nuclear Sciente Tohoku Univdersity Tel: +81 (022)-743-3400 _- fax: +81 (022)-743-3401 E-mail: koho@LNS.tohoku.ac.jp www.lns.tohoku.ac.jp/index.php UVSOR Ultraviolet Synchrotron Orbital Radiation Facility UVSOR Facility, Institute for Molecular Sciente, Myodaiji, Okazaki 444-8585, Japan http://www.uvsor.ims.ac.jp/defaultE.htm VU FEL W. M. Keck Vanderbilt Free-electron Laser Center 410 24th Avenue Nashville, TN 37212 Box 1816, Stn B Nashville, TN 37235, USA www.vanderbilt.edu/fel/