Closed Circuit Liquid Hydrogen Refrigeration System

Abstract

A liquid hydrogen bubble chamber has been maintained at 27°K with an automatically controlled closed circuit hydrogen refrigeration system of 300-w capacity. The system has been used continuously for more than 2000 hours on the 15-in. bubble chamber at the Lawrence Radiation Laboratory, University of California, Berkeley, California. The design uses commercially available heat exchanger tubing and controls. Actual performance is compared to predicted performance for design operating conditions. The refrigeration system is sufficiently flexible to be used on other experimental apparatus requiring refrigeration at liquid hydrogen temperatures.