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

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. Time

3. PhD = 1000 days

4. LT is difficult

5. A Cabinet of Curiosities ?
Ole Worm (1588-1654)

6. Helium

7. Another Curiosity ?
http://www.flickr.com/photos/noyespictures/228951299

8. Try Dry

9. Pulse tubes now to 2.7K
Dryogenic – DMS-1000 system

10. Wiring

11. http://www.flickr.com/photos/andrewmckaskill/16531297
“God hangs the greatest weights upon the smallest wires”
Francis Bacon

12. Don’t build
if you can buy

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. Pumps and
plumbing

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. • 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. Millikelvin work

18. http://www.flickr.com/photos/arcanegazebo/3299089
The dilution fridge – the mainframe of
mK machines

19. Keep it simple,
stupid !

20. Simplicity means achieving the
maximum effect with the minimum
means.
Koichi Kawana
http://www.flickr.com/photos/hynkle/2587828754

21. Entropy, S
Temperature

22. Entropy, S
B min = 0.1 T
B max = 6T
Temperature
T MIN <50mK T BATH = 4.2K, 1.5K

23. Refrigerant

24. Entropy, S
B min = 0.1 T
B max = 6T
Temperature

25. Superconducting
Magnet
Refrigerant

26. Entropy, S
B min = 0.1 T
1 B max = 6T
Temperature
T BATH = 4.2K, 1.5K

27. Bath
Thermal Contact
Superconducting
Magnet
Refrigerant
Pill

28. Entropy, S
B min = 0.1 T
1 B max = 6T
2
Temperature
T MIN <50mK T BATH = 4.2K, 1.5K

29. Bath
Heat Switch
Superconducting
Magnet
Refrigerant
Pill

30. Connection to Bath
Heatswitch
Sample Region (Double axis rotator)
Refrigerant
Practical Refrigerators

31. a
LT is difficult

32. http://www.flickr.com/photos/rakkar/574407246

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