Magnet O-Ring replacement:
After years and years these O-ring are cooling (Lhe refilling) and warming, it becomes hard and easily break. Helium gas can leak from the gaps. It is mistake to see the Helium boiling off is low, even no boil off (the floow metter shows zero flow rate). It is not suprise that ice is built up inside of the magnet, further cause magnet quench. Here is the easiest way to replace these O-rings or chcke them.
1. turn on the LHe meter to allow he gas pressure build up.
2. Unscrew the claimp, remove the O-ring and checm them if there is any damages.
3. Replace them if they were.
They are only two types of O-ring, One 35 and one 37. You can purchased from BOC Edwards.
see the pictures.