A brass thermometer for use in determining temperatures below 1° K

✍ Scribed by J.E Gordon; L.I Amstutz

• Publisher: Elsevier Science
• Year: 1965
• Tongue: English
• Weight: 324 KB
• Volume: 5
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(65)90078-0

✦ Synopsis

T H E availability of helium-3 has made the temperature region between 0.3 and l ° K one of reasonable accessibility. Above 0.7 ° K temperatures can be found from liquid helium-3 vapour pressure measurements. Below 0"7 ° K, however, the vapour pressure rapidly becomes small, and reliable measurements become difficult. The most accurate method of determining absolute temperatures below 0.7 ° K utilizes the Curie-Weiss behaviour of certain paramagnetic salts. Unfortunately the uncertainty in temperatures obtained from magnetic susceptibility measurements may easily be as large as five to ten millidegrees unless elaborate precautions are taken to eliminate extraneous magnetic effects. For experiments in which it is not feasible to take such precautions, or in which absolute temperatures need not be known with extremely high precision, it would be useful to have a comparatively simple, yet relatively accurate, thermometer for use between 0-3 and 0.7 ° K. Recent measurements of the low temperature electrical and thermal conductivities of brass indicate that a strip of brass can be used as such a thermometer.