AN AC CALORIMETER PROBE FOR A CLOSED-CYCLE CRYOGENIC STATION

The AC temperature technique is used to develop a calorimeter probe fo r measuring the specific heat of small samples. A commercial closed-cy cle refrigerator operating in the 8-300 K temperature range was used a s a cryogenic station. A theory of operation is presented and the expe rimental set-up is discussed. The calorimeter has been used to study t he nature of the magnetic and order-disorder phase transitions of seve ral materials. Specific heat data taken from a sample of chromel alloy (90% Ni-10% Cr) and a single-crystal sample of RbAS(4)I(5) show that the sensitivity of the apparatus to relative variations in the specifi c heat is about 0.1%.