Kyle
HAM1 currently vented but not nominally being purged (HIFO-Y noise), HAM2 under vacuum -> Closed HAM1 ion pump gate valve -> Opened HAM1 purge valve and exhaust of HAM1 turbo resulting in flow from bottom to top of HAM1 -> Returned to as found state after 90 minutes (purge valve closed, turbo exhaust capped) -> We are trying to systematically eliminate all adjacent external-to-vacuum potential helium reservoirs.  

Also, verified YBM leak detector calibration using external calibrated leak -> 5 x 10-8 torr*L/sec leak registered as 7 x 10-8 torr*L/sec value on detector -> Not a significant discrepancy for our current purposes -> left stored calibration factor alone