Search NASA⌕ Search

Engineering topics

Dixon, Kelly

Publications and source records attributed to Dixon, Kelly.

CHL1 2K COLD BOX REPLACEMENT

There is growing evidence showing that the cold compressors in the Modified Sub-atmospheric Cold Box (SC1/SCM) of the JLab Central Helium Liquefier (CHL) are approaching the end of their life. Their replacement parts are no longer available due to obsolescence, thus placing the Physics program at serious risk. A new sub-atmospheric cold box (SC1R), which hosts five technologically superior, water-cooled cold compressors and a similar 4K-2K refrigeration recovery heat exchanger, was funded in July 2017, to replace the existing 2K cold box. The design of the new 2K cold box and the external support system have been completed allowing the project to enter the fabrication and assembly phase, which will be completed here at JLab. We present the design, fabrication, installation and commissioning schedule of the new 2K cold box.

Yang, Shirley↗

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

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. Finally, we will briefly review the new 4.5 K cold box design features and discuss the commissioning and performance testing results.

42 ENGINEERING↗