Speakers from the UK, France, Italy and Japan converged on the University of Southampton on Monday 17th March to discuss the development of cryocoolers and their application in Research and Engineering. Organised by Dr Paul McDonald on behalf of the Institute of Physics (IOP) and the British Cryogenics Council (BCC), the conference was opened by Professor Price, Head of Engineering Sciences in Southampton.
Professor Tom Haruyama from the KEK High Energy Accelerator in Japan described a particle detector developed at the Paul Scherrer Institute in Switzerland for an experiment to measure the decay of muon particles. The detector is filled with extremely dense liquid xenon, approximately 900 litres of it – almost 10% of one year’s worldwide production. A pulse tube cryocooler designed to cater for a heat load of 150W at 165K has been developed and is now finding application on other liquid xenon experiments, in laboratories around the world.
Exceptional organisation and technical complexity were evident in a presentation by Dr Tom Bradshaw, Head of Cryogenics at the Rutherford Appleton Laboratory, on the cooling system for the Planck space project, due to launch in 2008. Planck will measure the cosmic microwave background to unprecedented accuracy and the cryogenics group at Rutherford Appleton has developed a closed-cycle refrigerator with a Joule-Thomson stage to provide cooling to 4K.
This is part of a cryogenic chain which marries with other systems from the US and France, cooling the detectors down to 100mK. With 16 units in orbit, the Rutherford Appleton design is arguably the most successful cooler flown in space, exploiting resonance to run on low power and achieving extremely long life, using flexure springs and non-contact seals – one unit has been operating for sixteen years.
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