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© DASA Dortmund, Photo: Uwe Völkner

The great attraction for your science show.

Your visitors will hardly believe their eyes!

Large Diffusion Cloud Chamber Invisible Becomes Visible

Make the Invisible Visible.

Visualize cosmic and natural radiation and make this phenomenon understandable! Historically, the Cloud Chamber was the first particle detector for making ionizing particles visible. Its working principle is based on supersaturated vapour. This vapour shows tracks of condensated alcohol while being penetrated by ionizing particles. Vapour clouds build up along the particle tracks, which are sometimes thin and long, sometimes thick and round or bulbous. They may appear gradually or pop up all of a sudden or move very fast like a projectile splintering into all directions. The action that is constantly taking place in the Cloud Chamber is so fascinating that you simply have to see and experience it with your own eyes.

Cloud Chambers don't play a role in current research any more, but today they are used increasingly at universities and high schools for teaching radioactivity. In museums, science centers and even in art shows, for example at the exhibition for contemporary art, Documenta (it was on display at Documenta VI and Documenta X), the Cloud Chamber is used to be main attraction.

1-4 kV (heater and ion extraction)

Observation chamber

Heater Duct

Glass covers Vapour Lock

Liquid

Saturated/ supersaturated vapour

Heater Alcohol feed

Alcohol return flow

Cooling

Black metal plate

Chamber base

Construction and function PHYWE’s Diffusion Cloud Chambers consist of the chamber base and the actual observation chamber.

The chamber base contains cooling unit, power supply, alcohol tank, alcohol pump and timer switch. The transparent observation chamber is located on top of the base.

The bottom of the chamber consists of a solid, black anodized metal plate which is uniformly cooled to about –30°C over the whole area by the cooling unit. The top surface and walls of the observation chamber consist of two glass covers, one inside the other.

Condensation of alcohol on the glass plates is prevented by thin heating wires between the two glass panes. At the same time this wire grid is used as a high voltage grid for ion extraction.

Below the glass cover an electrically heated duct is located which extends around the whole circumference. Drops of isopropyl alcohol from a reservoir container are continuously pumped into the duct.

The alcohol evaporates and diffuses from the upper, warmer part of the chamber to the cold chamber bottom. Here the alcohol vapour condenses and flows back into the reservoir container. A layer of supersaturated alcohol vapour forms above the thin layer of liquid covering the bottom. In this region, and only here, charged particles coming from inside or outside the chamber produce ions along their flight path. Isopropyl alcohol droplets become preferentially attached to the ions thus producing cloud tracks, which can be observed. The type of ionising particle can be deduced from the length and nature of the particle track.

Observe the natural background radiation What can you observe in the Cloud Chamber?

PHYWE´s Diffusion Cloud Chambers are suitable for observing natural background radiation, i.e. the type of radiation which surrounds us wherever we go. There are two types of natural radiation: cosmic radiation and the natural radioactivity of the earth. The ever-changing patterns of both types of natural radiation can be observed simultaneously thanks to the large observation area.

The cloud tracks gradually gravitate downwards and disintegrate before reaching the bottom plate just to be replaced by ever new cloud tracks.

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All electrically charged particles can be detected in the Cloud Chamber: ␣-particles (1), ␤-particles (2), protons (3), myons (4), electrons or positrons.

Delve into the world of cosmic and terrestrial radiation. For more information about PHYWE's fascinating Cloud Chamber, including video files showing different types of radiation, visit our website under www.phywe.com/cloudchamber/

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The Cloud Chamber is: 쮿 Attractive & informative Designed for universities, schools and as an educational tool in science shows and science museums as well as in nuclear power stations.

쮿 Unique large observation area The observation area with a size of about 1 square meter is accessible from all 4 sides. The cloud tracks can be observed by conveniently looking down on them.

쮿 Reliable & safe Designed for long life and continuous operation.

쮿 Easy to run – automatic operation Fill up and switch on. Within a few minutes the Cloud Chamber is running fully automatically. Timer control for automatic switch-off after closing hours.

쮿 Minimum maintenance The only maintenance procedure is a refill of the alcohol tank once every 3 to 4 month.

쮿 Top quality – long-term experience PHYWE has been building Large Diffusion Cloud Chambers for more than 25 years.

with the Large Diffusion Cloud Chamber

Technical data

Large Diffusion Cloud Chamber PJ 80 (Order no. 09043-93)

Small Diffusion Cloud Chamber PJ 45 (Order no. 09046-93)

800 x 800 mm

450 x 450 mm

Chamber base (H x W x D)

1280 x 1280 x 1280 mm

600 x 640 x 640 mm

Working liquid

2-Propanol, pure (isopropyl alc.)

(1-l-bottle, Order no. 30092.70)

2-Propanol, pure (isopropyl alc.)

(1-l-bottle, Order no. 30092.70)

10 liters

2 liters

Observation chamber (Dimensions of active surface)

Tank volume Temperature gradient Temperature of outer surface Illumination

50...-35°C

50...-35°C

slightly warm (less than 27°C/80°F)

slightly warm (less than 27°C/80°F)

4 built-in fluorescent tubes (80 cm long, 30W each, Lifetime approx. 10,000 hrs)

2 built-in fluorescent tubes (38 cm long, 36W each, Lifetime approx. 10,000 hrs)

Timer switch

7 x 24 hours (Week program)

7 x 24 hours (Week program)

Mains supply

115/230 Volt, 50/60 Hz

115/230 Volt, 50/60 Hz

Power consumption

1,9 kVA

0,9 kVA

Weight

450 kg

80 kg

Numerous accessories for the Cloud Chamber, e.g. different radioactive sources, emitters or complete experiments with the Cloud Chamber, can be found under www.phywe.com/cloudchamber/

Large Diffusion Cloud Chamber PJ 80, front panel removed.

The control panel is in the upper area, alcohol tank and alcohol pump are below.

Attention ++ Rental instead of buying ++ Attention ++ Rental instead of buying ++ Attention ++ Rental instead of buyOur rental service is very popular as we not only provide the instrument but also supply directly to the showroom, perform setup and brief your staff. Short-term leasing is possible as well.

Please contact us directly so that we can give you an individual offer.

You reach our Cloud Chamber specialists under phone +49 551 604136 or by email under cloudchamber@phywe.com.

Your visitors will hardly believe their eyes!

Isotopolis, Dessel, Belgium

Universum, Bremen, Germany

DASA, Dortmund, Germany

Information Center Nuclear Power Station, Dukovany, Czech Republic

Niigata Science Museum, Japan

References

“The Large Diffusion Cloud Chamber is a highlight of our exhibition and brings our visitors to being astonished and staying.”

Dr. Tobias Wolff, Head of Exhibition and Research, Universum Science Center, Bremen, Germany “The Diffusion Cloud Chamber has been working in our Information Centre since 1997 appreciated by centre visitors.”

Veronika Vespalcova, Head of Information Centre, Dukovany Nuclear Power Station, Dukovany, Czech Republic “The chamber continues to work well. Our visitors are amazed at it.”

“The Diffusion Cloud Chamber is on exhibition in our museum since 1990. Already in normal continuous operation, when cloud tracks become visible from the natural radiation, the Cloud Chamber is a highlight in the constant exhibition "nuclear energy and industrial application".

For visitors and especially for interested young people it is a "magnet". That applies in particular for the demonstrating show, when we put a radioactive preparation inside. We would not like to miss the Cloud Chamber as an elementary part of the permanent exhibition.”

Dr. Hartmut Knittel, Trustee at the Federal State Museum Mannheim, Mannheim, Germany

Dr. Martin Weiss, Vice President, New York Hall of Science, New York, USA “Phywe's diffusion cloud chamber is working excellently. As it was foreseen the chamber is one of the main attractions at our exhibition.”

“Our museum’s Cloud Chamber was installed on 1990, and since then it has been working well. The participants (our museum visitors) can well understand the meaning of radioactive radiation phenomena.”

Dr. Peter Raics, Nuclear Research Institute of Hungarian Academy of Sciences, University Debrecen, Hungary

Toshiaki Iwami, Head of Physics and Chemistry Exhibition, Niigata Science Museum, Japan

www.phywe.com/cloudchamber/

Errors excepted. Subject to technical alternations. Please refer to our general terms and conditions of sale.

Art.-No. 00192.02

PHYWE Systeme GmbH & Co. KG Robert-Bosch-Breite 10 D - 37079 Goettingen Germany Phone: +49 551 604-0 Fax: +49 551 604-115 e-mail: info@phywe.com Internet: www.phywe.com