Performance of RHIC 50 Watt Recoolers

Abstract

Brookhaven National Laboratory has designed and tested cryogenic heat exchangers for use in the Relativistic Heavy Ion Collider (RHIC). These units, called recoolers, are located periodically in the superconducting magnet string and maintain the accelerator at design temperature by removing heat from the closed Helium circulating loop. Each is required to transfer 50 Watts from supercritical Helium, nominally flowing at 100 g/s to a Helium bath boiling at 4.25 K. With a 50 Watt heat load applied, there is a.028 K differential temperature between the Helium exiting the recooler and the recooler bath, and a heat exchange effectiveness of approximately 80%. The recoolers met design requirements during first article testing and then during the RHIC first sextant test. This paper describes the design and testing of the recoolers as well as their performance during the RHIC first sextant test.

Work performed under contract with the US Department of Energy.