High Flux X-ray Diffraction for Materials Analysis

Source: Dr. Cameron Chai

Rotating anode X-ray generators are responsible for producing the highest X-ray fluxes for X-ray diffractometers (XRD) outside of a synchroton. Rigaku first introduced Rotating anode technology in the 1970’s and have continued to refine the technology. The SmartLab is the most powerful lab-based XRD on the market, but also the most reliable ensuring optimum beamtime and the longest lifetime. It is not uncommon for these generators to function for 20 or 30 years.

These systems provide the number of photons required to analyse and characterise the most challenging materials.

Rotating Anodes Sources for Powder and Thin Film XRD

Rotating anodes provide significantly more power than conventional sealed tube X-ray generators. By way of comparison, refer to the diagram below. High flux rotating anode XRDs allow you to see the finest details in the fastest timeframes, maximising your throughput rates. Furthermore, the high flux offers you the best chance of detecting trace phases which could be the difference between success and failure. With a lifetime of 20 years plus, a highflux XRD offers the most futureproof solution, catering for the largest range of potential sample types and measurement modes. A recent re-design of the PhotonMax rotating anode source has increased its lifespan by more than three times compared to the previous design.

Power Density

Having a high-power X-ray generator is a mandatory starting point. But optics, used to gather and focus X-ray photons onto the crystal and monochromatize the beam (Kβ is essentially filtered out), are as important. Rigaku also has a long history of success with graded, multilayered optics and switchable Cross Beam Optics (CBO) specifically designed for each type of diffractometer and each wavelength ensuring a maximum number of photons is being focussed onto the region of interest.

Detectors

The other key component of an XRD is the detector. The ideal detectors for use with high-flux X-ray sources are HPC (Hybrid Photon Counting) detectors like the HyPix-3000. These detectors provide highresolution, high count rates, no noise, and the ability to operate in 2D mode under ambient conditions. HPC detectors are next generation semiconductor detectors that directly measure every photon generated by your sample. The simpler, more direct process in HPC detectors allows for each incoming X-ray photon to be counted immediately in true ‘shutterless’ mode. In turn, data loss is minimised, electronic noise is avoided, and signal-to-noise statistics are dramatically improved.

Another important aspect that contributes to their high performance is the fact that each pixel of a HPC detector has its own individual reading channel. This prevents any possible charge sharing between adjacent pixels, creating a top-hat, single pixel Point-Spread-Function. This results in greatly improved resolution of Debye-Sherrer rings, further improving signal-to-noise statistics and allowing for the detector to be placed very close to the sample for shorter data collection experiments.

Benefits of High-Flux for Diffraction Studies

> Faster, accurate, high quality data collection – In conjunction with highspeed, high accuracy goniometers and

HPC detectors, the higher flux X-ray source allows you to collect data faster > Higher throughput – Faster scans leads to higher sample throughput rates > More easily detect trace phases –

With higher count rates, trace phases become easier to discern > Maximise synchrotron time – By using your high-flux XRD, you can better screen samples that need to be analysed at the synchrotron > Proven Reliable technology > The most futureproof solution –

Catering for potential experiments and materials in the future