Programmed Temperature Controller and Cryostat

Abstract

A cryostat and programmed temperature controller has been developed to heat solid samples from liquid helium temperature to room temperature (4 to 300°K) so that their temperature increases according to a specified function of time. It can be operated at various heating rates and has been tested using linear heating rates of 0.5 to 20°K per minute. The desired temperature profile is obtained as a voltage from a function generator. This voltage is compared to the emf from a sensing thermocouple and the difference signal used to adjust the sample compartment heater. Any arbitrary monotonic temperature vs time function may be obtained by adjusting resistors in the function generator.