Measurement of thermal expansion at low temperatures

✍ Scribed by G.K. White

• Publisher: Elsevier Science
• Year: 1961
• Tongue: English
• Weight: 88 KB
• Volume: 1
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/s0011-2275(61)80021-0

✦ Synopsis

AN apparatus for calibrating thermocouples from 4 to 300°K is described. It has been used to obtain a detailed calibration table of the thermoelectric power and potential difference for constantan, gold-cobalt (gold-2.1 atomic per cent cobalt), and 'normal' silver (silver-0.37 atomic per cent gold) versus copper. At low temperatures gold-cobalt versus copper has a much larger thermoelectric power than does constantan versus copper (respectively 16 and 6 ~tV/deg.K at 20 ° K). Unfortunately, however, it is also more inhomogeneous, so that uncertainties in temperature measurement are approximately the same. The 'normal' silver is thermoelectrically very similar to copper. Results are included of inhomogeneity, annealing, and long-time stability tests.