A note on the magneto-resistance of carbon thermometers

✍ Scribed by N Kollias; J Dreesen; M Giles; C Terry

• Publisher: Elsevier Science
• Year: 1971
• Tongue: English
• Weight: 92 KB
• Volume: 11
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(71)90016-6

✦ Synopsis

temperature resistance. The operating current for heating to T= 20K was 8-10 mA and the rate of evaporation of helium was then less than 1 cm -3 min -~ per cm heater length. For short periods, heating up to nitrogen temperature and above can be achieved; for 30 mA T~75K, V/l~lOcm 2 min.l and for a current of 50mA T~200-250 K, V/I~30 cm: min7 ~ It is evident that it is more convenient to use liquid hydrogen to obtain intermediate temperatures between hydrogen and nitrogen, and liquid nitrogen for higher temperatures. The thermal inertia is higher the better the insulation. The time for heating up, for example, from 4"2 to 20 K varies between 10 and 25 s, depending on the material and diameter of the jacket.

When studying semiconducting specimens, which have high electrical resistivity at helium temperatures, the heater can be dispensed with, using the heating of the specimen by the measuring current, and the specimen can simultaneously be used as a thermometer.