Use of Graphite as Low Temperature Support and Shunt for Heat Switch

Abstract

Artificial pitch‐bonded graphite is known to exhibit an extremely large variation of heat conductivity with temperature. It is both rigid and strong, and below 1°K its heat conductivity is exceptionally small. For these reasons we have found it to be an ideal support material for use within the adiabatic enclosure of a cryostat operated below 1°K. Furthermore, above liquid nitrogen temperature graphite is an excellent heat conductor, and when used in parallel with a lead heat switch, it proves unnecessary to admit exchange gas during the precool period. The graphite exhibits a strong pumping action for helium gas at low temperatures.