Commissioning and Testing of a new 4.5K Cold Box for JLab Cryogenic Test Facility

摘要

A new 4.5K cold box at Jefferson Lab (JLab) Cryogenic Test Facility (CTF) was recently installed and commissioned to upgrade the existing 4.5 K refrigeration system and work in parallel with the existing 4.5 K cold box. This new 4.5 K cold box is equipped with two turbo-expanders and, at its maximum capacity condition, it is expected to support at least 6.6 g/s of helium liquefaction or 650 W of refrigeration at 4.5 K. It can also handle up to 10 g/s 30 K return flow for 2 K refrigeration recovery that supports cryo-module and superconducting cavity testing. Performances of the cold box at its maximum capacity conditions as well as several other operating modes were tested for acceptance. We will briefly review the new 4.5 K cold box design features and discuss the commissioning and performance testing results.