STABILITY STUDIES ON CHINESE GERMANIUM RESISTANCE THERMOMETERS DESIGNED FOR USE IN MAGNETIC-FIELDS

The stability of 15 doubly doped germanium resistance thermometers, manufactured in China and designed for use in magnetic fields, has been studied under zero magnetic field conditions while the thermometers were subjected to thermal cycling between 15 K and room temperature and between 85 K and room temperature. Resistance measurements were made on each thermometer at 15 and 20 K on the 15 K cycles and at 85 K on the 85 K cycles. The stability of the thermometers at 20 K was found to range from 1 to 300 mK. Major differences in behavior between thermometers made from n- and p-type doped germanium were observed; many of the n-type thermometers showed good stability while there were significant resistance changes for all of the p-type thermometers.