Precise Nuclear Resonance Thermometer

Abstract

The properties of a thermometer based upon the temperature variation of the pure quadrupole resonance frequency (ν0) of the Cl35 nucleus in granular KClO3 have been investigated. In the range ∼10°K<T <300°K, the thermometer has a very high sensitivity, being better than ±0.002° at 273°K and ±0.004° at 77°K. The accuracy at 20°K is estimated as at least ±0.02°. The thermometer is exactly reproducible if care is taken that the KClO3 is of high chemical purity. No hysteresis effects were observed. Establishment of the thermometer requires a single precise determination of the ν0 versus temperature curve using the fundamental temperature standards to measure the temperature.