Cryogenic Facilities for 75cm Hydrogen Bubble Chamber

Abstract

A hydrogen bubble chamber with 200 liters of liquid, 78cm in diameter is under construction at Institute of Nuclear Study, University of Tokyo. A simple Linde refrigeration cycle is provided, as such a system meets the design considerations of this chamber. In order to establish the required capacity of the refrigerator, the static and dynamic heat loads were analyzed. Designing for a cycling rate of two expansions per second gives an estimated total heat load of 920 watt, including safety factors. A refrigerator with a capacity of 1, 000 watt at 26°K, therefore, was designed for this chamber, and brief descriptions of this refrigerator are given. For the precise control of the temperature of the chamber liquid, an elaborate temperature control loop configuration was considered, and the hydrogen temperature circuit schematic is shown.