HIGH PRECISION TEMPERATURE CONTROLLER FOR EXPERIMENTAL CRYOSTATS

A general purpose instrument is described which is capable of providing temperature control to better than 1 mK for long periods in a wide variety of cryogenic applications. The main first and second order effects contributing to temperature instability are taken into consideration. For a range from 2 to 300 K at least two temperature sensing elements are required. The bridge circuit described is designed for use with an Allen-Bradley type carbon thermometer below 20 K and a copper or platinum thermometer above 20 K. Details of the circuit and constructional features of the controller are included. © 1969.