[Hallb] Bad News - FROST SHIFTS CANCELED

[Bill Briscoe]

Dear Collaborators,

The cryogenics team has made several attempts at fixing the super-fluid leak that occurs when the temperature drops below 2K. These attempts included both g9b and g9a inserts. Chris feels that the leak is at the sealing surface inside the refrigerator rather than at the Kapton seal.  His guess is that the indium o-ring is the culprit, and that can only be changed by disassembling the cryostat down
to the mixing chamber itself.  This can be accomplished in the hall, but
it's a major operation. 

In light of this, FROST shifts will remain canceled for the next 7 days and it is possible that they will remain canceled for up to 10 days. We will send out an update at the beginning of next week. 

It may be that other tests scheduled for late next week will be moved up, but we will know more about that after the 8:00 meeting tomorrow.

Bill