Cryogenics in Oxfordshire Harry Jones*, Clarendon Laboratory, Oxford. Office, room number 166

1. Cryogenics in Oxfordshire Harry Jones*, Clarendon Laboratory, Oxford. Office, room number 166 Room 166, so? Isn’t that too much information? Well ……. In 1968, an apprehensive 23 year old (me) was taken into that office to be introduced to the great Professor Nicholas Kurti CBE FRS. *19 days into his 49th year in cryogenics and magnets H. Jones Cluster Day 28-09-11

2. In effect, we have to thank Adolf Hitler for cryogenics in Oxfordshire And Frederick Lindemann (later Lord Cherwell) Head of the Clarendon Laboratory. Anti Semitism in Germany in the 1930s was rife. This gave Lindemann the idea to offer refuge to top quality Jewish physicists especially those who worked in the area of low temperatures. The result: Franz (later Sir Francis) Simon, Kurt Mendelssohn, Heinrich Kuhn and ……... H. Jones Cluster Day 28-09-11

3. Nicholas Kurti who had been Simon’s student and post doc in Berlin and Breslau (now Wroclaw, Poland). “ “ H. Jones Cluster Day 28-09-11

4. Low temperature work really took off in the Clarendon laboratory in the 1930s As did magnetic fields. We all know, now, that magnets need low temperatures – liquid helium etc, but these were the days before superconducting magnets (although Mendelssohn was writing to Nature suggesting superconducting PbBi wire magnets as long ago as 1933). Back then, it was the other way round. High magnetic fields were needed to get low temperatures, i.e., adiabatic demagnetisation of paramagnetic salts. Hence the famous 2 MW ex tramways generator that allowed fields up to 12.5 T in the Clarendon By 1956 Kurti achieved a millionth of a degree kelvin using nuclear demagnetisation and Parks Road Oxford was the coldest spot on earth. In 1960 Kurti repeated the experiment on live television (Tomorrow’s World) and the record stood for 18 years (see Guinness Book of Records!) H. Jones Cluster Day 28-09-11

5. The legacy of all this seeped into Oxfordshire – and elsewhere. • Oxford Instruments, the university’s first spin out company was founded – See Audrey’s excellent book “Magnetic Venture” • Another Clarendon Man, Jeremy Good (Mendelssohn’s student), founded a company called, Cryogenic • Mendelssohn founded the journal “Cryogenics” in Oxford • Yet another Clarendon man, Ralph Scurlock, founded the Institute of Cryogenics in Southampton • Kurti was a co-founder of the British Cryogenics Council (its current chairman is a Clarendon man …..) • John Cosier and Mike Glazer (both Clarendon men) founded Oxford Cryosystems (Long Hanborough) • Heinz London proposed the 3He/4He dilution refrigerator at a conference in the Clarendon “The Harwell fridge” that was developed by OI. • And, of course, Harwell, RAL (or NIRNS as was) and Culham (the famous Goodall chart) were all strong centres of cryogenics.Although, until 1974, they were in Berkshire NOT Oxfordshire. I’m sure there’s lots I’ve forgotten / didn’t know in the first place. You might call the above “direct impact”……………… H. Jones Cluster Day 28-09-11

6. How did things spread ? • This is not in chronological order • After OI, other “cryogenic” companies formed sometimes from OI • Thor Cryogenics Magnex (ElScint) - Berensfield • Technology Systems (brief but existed) - Witney • AS Scientific – Abingdon • OMT (Eynsham) morphed into Siemens Magnet Technology (SMT) • Thames Cryogenics - Didcot • Scientific Magnetics (previously Space Cryomagnetics) - Abingdon • ICE Oxford • Cryophysics - Witney As previously listed: Cryogenic1 and Cryosystems 1 Not in Oxfordshire H. Jones Cluster Day 28-09-11

7. CRYOGENIC CLUSTER - The Most Powerful Concentration of Cryogenic Expertise on Earth So, Hitler and the Clarendon Laboratory have a lot to answer for. Lots of cryogenics over some 80 years (of the hundred or so years of LHe and superconductivity) not exclusively Oxfordshire of course but rather Oxford – centric. And here we are today, in Oxfordshire with the Cryogenic Cluster and H. Jones Cluster Day 28-09-11