Study of heat inflow using heat exchange gas in a shaft cryostat based on GM cryocooler

A. Chernikov, A.Buzdavin

Based on the development of top-loading cryostats a horizontal-loading cryostat for cryomagnetic research at the diffractometer DN-12 of IBR-2 has been developed. In this regard, it is necessary to study the value of the heat inflow due to the heat exchange gas in the horizontal-loading cryostat. For this purpose an express GM cryocooler cryostat has been performed. This cryostat has a vertical stainless steel tube, which is connected to the second stage of the cryocooler by means of a copper thermal bridge. The tube was filled with helium gas and the cryostat was installed in several positions by rotation relative to the vertical axis in the range of 0-180 degrees. During the experiment, the temperature of ends of the thermal bridge was measured. It is experimentally shown that the heat inflow due to the heat exchange gas is insignificant in any position of the cryostat. The pressure of the heat exchange gas was 0, 2, 10 and 20 mbar.