Location and Function
The fridge (or refrigerator) is inserted into the inner space of the target magnet from the top. It takes LHe from the magnet LHe space thru its "separator" and stores LHe in its bottom-most space called "nose". The nose space is cooled down to 1 K by the helium evaporation method. The evaporated helium is pulled by the roots pump thru the gate valve or the gate-valve bypass.
Sensors
Operations
- The incoming helium to the fridge is controlled by the fridge valves, namely the run valve and the bypass valve. Operational procedures are explained on this page [Fridge Valve Control System at NM4].
- The outgoing helium from the fridge is controlled by the gate valve and the gate-valve bypass. Operational procedures are explained on this page [How to control the Fridge Return flow (GV and GV Bypass)].
Important Facts
How long does the fridge would last if the starting liquid level is 100%? ~ 8 hrs from (100% to 10%) with maintaining cernox 7 temperature below 50 K
Note: Set Separator flow to 10slm.
https://e906-gat1.fnal.gov/data-summary/e1039/target-all.php?sel_mode=date_time&Y0=2024&M0=06&D0=16&h0=20&m0=00&s0=00&Y1=2024&M1=06&D1=17&h1=11&m1=10&s1=00&Cryo+Temperature_Cernox+7&Cryo+Level_Nose+LHe+Level
- How long does the fridge would last if the starting liquid level is Heat Ex. Bottom? ~16 hrs
- How long would the fridge be cold if the level probe reaches zero? ~1.5-2.0 hrs