A precision nuclear quadrupole resonance thermometer

A fully automatic precision thermometer using the NQR absorption of KCIO
3
has been developed. The temperature absorption signal is automatically “searched.” The search frequency is locked to the center of the absorption signal and is converted to a temperature scale. Temperature readings from 77 to 374 K, with accuracy, reproducibility, and stability confirmed to ±1 mK at the triple point of water have been obtained.