Calorimeter for heat capacity measurements from 2 to 80°K

Abstract

A calorimeter is described for making reasonably accurate heat capacity measurements from ∼80°K downwards. It has been tested to 2°K and should be effective down to ∼1°K. A thermal switch is used for cooling the sample container, the temperature of which is measured with a doped germanium thermometer, and a shield is incorporated for adiabatic working in the upper part of the temperature range. Test experiments have been made on benzoic acid from ∼5 to 80°K, and on cupric chloride dihydrate from 2 to 8°K. Smoothed C_p values for these substances are given at regular temperature intervals and comparisons made with previous determinations.