When the fridge is in Hold Cold Mode, it means we have a liquid in the fridge nose and holding target material. In that case, we must keep the target material to preserve the paramagnetic centers. In the Hold Cold Mode, you will see the fridge parameters as follows:
We fill the fridge to Heat-Ex Top for the Cold Hold Mode and close the Run and Bypass valves. To reduce LHe consumption in the fridge nose, set the GV bypass pressure on PID at 100 torr and Set the Separator flow at 20slm.
Keep monitoring the target parameters, say Insert#7, Insert #8, Annealing A, and Annealing B. Where Insert #7 and Insert# 8 are the Cernox (CX-1030) sensors on the Top and Bottom cup of the target insert. Where Annealing A and Annealing B are the metal temperature in the fridge, monitor these four target parameters. Where Insert#7 and Insert# 8 are in resistance (Ohm) and Annealing A and Annealing B are in temperature (K). Please see a screenshot below for these target parameters:
Please follow this page to put the fridge in the Cold Hold Mode: Cryo-control parameters / conditions when the fridge is in Hold Cold Mode - Wiki Post Portal - Confluence (virginia.edu)