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Research Fellow in Cryogenics

Name: Cllr. Dr. Bob Ray

Job title: Research Fellow in Cryogenics

What education and qualifications do you have?

BSc, PhD

Give an outline of your career so far

Employment History
1983-1989 British Rail, Clerical Officer (Luton, Newark, Brighton, Harrogate, Oxted, London (ERTC))
1989-1991 Nursing Home, Kitchen Assistant; Landscaping Firm, Gardening; Great Yorkshire Show, Car Parking (all in Harrogate)
1999-2006 UCL-MSSL, Research Fellow (Holmbury St. Mary)

Educational History
1989-1991 Harrogate College of Arts & Technology, A-Levels (Harrogate)
1991-1994 Royal Holloway, University of London, BSc Physics (Egham)
1994-1998 Royal Holloway College, PhD

Why did you choose this career path?

They all seemed like good ideas at the time. To start with I'd always wanted to work for British Rail. With Tory privatisation plans taking hold in the late 1980s, the job became less enjoyable and fulfilling. I took voluntary redundancy in 1989. I had to think what I could do next. Taking a couple of years "off" to do A-levels seemed like a reasonable choice. I enjoyed studying so decided to continue. Physics was interesting so I chose this as a subject to study at university. My PhD was in experimental low temperature physics. I chose this because I wanted to do something with variety. Hands on experimental work, solving practical problems, collecting and analysing data, writing reports, etc. Other PhDs, for example high energy physics, were mainly sat in front of a computer all day, this was not for me. The job at MSSL was advertised in New Scientist. Although I didn't think I'd have a cat in hellâs chance, amazingly I did get the job, and was over the moon about it.

If I had my time over again, I probably wouldn't choose this path. At the age of 36 on £21 500, with house and fuel prices as they are, I'm still in exactly the same position I was nearly 20 years ago. However, I have met many interesting and good people over the years, many of whom I continue to be friends with. This I would not change. If it were possible to have my time over again, I would have gone straight from school to college and then to university. Something my parents and teachers wanted me to do, but would I listen? No! I had to choose the hard road. Looking back, I would still have chosen Physics to study at university, not only because it's a fascinating subject, but because physicists are a great bunch of people.

What does your current work involve?

I'm involved in developing a fridge that will cool x-ray detectors to a temperature of -273.05 degrees Centigrade (100 mK). The fridge and detectors will be launched in a rocket in 2003 [Errr.. there's been some timeline slippage.. Ed.]. Both the European Space Agency (ESA) and NASA intend launching a new generation of X-ray telescopes within 15 years. The requirement for these new telescopes is that, once in space, they should require as little human intervention as possible, maybe once every 10 years. In the past, liquid 4He has been the preferred refrigerant, however, after about 2 years it has boiled away. So what happens to the telescope? Two choices: a space shuttle can be sent up to replenish the lost helium on the telescope, or, the telescope can be left to burn up in the Earth's atmosphere. Both these options are very expensive. So scientists are, at this very moment, researching into using mechanical coolers, powered by the Sun, to cool to the same temperatures as liquid helium that will meet the specified requirements. Scientists at MSSL are involved in meeting these requirements. Clearly, with developing new technology, a lot of research has to be done. This is where I come in.

Currently I'm:
- Developing a mechanical and superconducting heat switch
- Working on being able to maintain 100 mK during flight

The latter may sound easy enough in a laboratory environment, but in a rocket? Something I haven't mentioned so far is how we cool from around liquid helium temperature (4 K) to around 100 mK. We use an Adiabatic Demagnetisation Refrigerator (ADR) which contains "Salt Pills" (e.g. Ferrous Ammonium Alum (FAA)). A large magnetic field (around 3 T) is applied to the "Salt Pill", as a consequence the pill warms, so we have to wait until it cools to its original starting temperature (this is achieved by connecting the mechanical cooler to the salt pill via the mechanical heat switch). Once at around 4 K again, the heat switch is opened, thermally isolating the pills. The magnetic field is reduced and the pills cool to around 1 K. The same process is then repeated, with the final salt pill reaching 100 mK and being thermally isolated from the first by the superconducting heat switch. Once at the X-ray detector operating temperature, a temperature controller will maintain 100 mK, the detectors will detect some X-rays and Bob's your uncle.

Hobbies and interests outside work

Hiking, growing vegetables, music. I was elected a borough Councillor in May 2002, so this takes up most of my free time nowadays.

Bob in the Cryo Lab

Scary gizmo in the Cryo Lab

Mullard Space Science Laboratory - Holmbury St. Mary - Dorking - Surrey - RH5 6NT - Telephone: +44 (0)1483 204100 - Copyright © 1999-2005 UCL

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