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Low Temperature Techniques Course 2008

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Presentation given at the Institute of Physics Low Temperature Course 2008, sponsored by Cambridge Magnetic Refrigeration

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Low Temperature Techniques Course 2008

  1. 1. Notes to a Low Temperature Physicist or, what I wished I'd have known when I started LT Techniques course, 26th Nov 2008 Dr Kurt Haselwimmer Cambridge Magnetic Refrigeration
  2. 2. Time
  3. 3. PhD = 1000 days
  4. 4. LT is difficult
  5. 5. A Cabinet of Curiosities ? Ole Worm (1588-1654)
  6. 6. Helium
  7. 7. Another Curiosity ? http://www.flickr.com/photos/noyespictures/228951299
  8. 8. Try Dry
  9. 9. Pulse tubes now to 2.7K Dryogenic – DMS-1000 system
  10. 10. Wiring
  11. 11. http://www.flickr.com/photos/andrewmckaskill/16531297 “God hangs the greatest weights upon the smallest wires” Francis Bacon
  12. 12. Don’t build if you can buy
  13. 13. http://www.cmr-direct.com Rewiring a cryostat properly costs less than getting a power socket installed. Do it right and do it only once.
  14. 14. Pumps and plumbing
  15. 15. http://www.flickr.com/photos/arcanegazebo/445426559 / “A vacuum is a hell of a lot better than some of the stuff that nature replaces it with” Tennessee Williams
  16. 16. • Always clean and grease o-rings • Only Use Viton O-rings – buna-N cracks • Paint your KF-fittings • Don't use poppet relief valves on vacuum cans • Always boil-off flux on HS joints • Buy SS flexibles from Kurt J Lesker • Use plastic KF clamps from BOC edwards • Use only bellows sealed valves on He-3
  17. 17. Millikelvin work
  18. 18. http://www.flickr.com/photos/arcanegazebo/3299089 The dilution fridge – the mainframe of mK machines
  19. 19. Keep it simple, stupid !
  20. 20. Simplicity means achieving the maximum effect with the minimum means. Koichi Kawana http://www.flickr.com/photos/hynkle/2587828754
  21. 21. Entropy, S Temperature
  22. 22. Entropy, S B min = 0.1 T B max = 6T Temperature T MIN <50mK T BATH = 4.2K, 1.5K
  23. 23. Refrigerant
  24. 24. Entropy, S B min = 0.1 T B max = 6T Temperature
  25. 25. Superconducting Magnet Refrigerant
  26. 26. Entropy, S B min = 0.1 T 1 B max = 6T Temperature T BATH = 4.2K, 1.5K
  27. 27. Bath Thermal Contact Superconducting Magnet Refrigerant Pill
  28. 28. Entropy, S B min = 0.1 T 1 B max = 6T 2 Temperature T MIN <50mK T BATH = 4.2K, 1.5K
  29. 29. Bath Heat Switch Superconducting Magnet Refrigerant Pill
  30. 30. Connection to Bath Heatswitch Sample Region (Double axis rotator) Refrigerant Practical Refrigerators
  31. 31. a LT is difficult
  32. 32. http://www.flickr.com/photos/rakkar/574407246
  33. 33. Cambridge Magnetic Refrigeration www.cmr.uk.com Cryoconsumables - wiring, connectors etc www.cmr-direct.com Completely Dry systems -Dryogenic Ltd www.dryogenic.com Dr Kurt Haselwimmer Kurt@cmr.uk.com

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