Cooling of a system of superconducting magnets by means of pumped subcooled liquid helium

In the course of developing the refrigeration system for the Fermi National Accelerator Laboratory energy doubler, a new concept was developed for the cooling of long, superconducting magnet systems. The concept depends on: a) the use of pumps for the transport of liquid helium and refrigeration, and b) heat transfer between a stream of boiling helium and one of subcooled liquid helium for maintenance of a constant temperature of the fluid surrounding the magnet windings. In order to verify the validity of the concept an experimental program at Fermilab was started. This paper describes the experimental installation and some of the test results obtained during a number of test runs.