J. Kissel, N. Mavalvala, K. Ryan, D. Sigg

We've successfully completed the second cycle of the Test Mass Discharge System on H1 SUS ETMY (BSC9/BSC5). 

Operation went much more smoothly today that yesterday. We were open to the chamber sending ions in by 08:00a PDT, and valved out by 08:30a PDT. We decided only to go up to a BSC chamber pressure of 15 [Torr], partially due to person-power constraints, but mostly because the bulk to the ion neutralization happens when the TMDS is first valved in; as more clean air is in the chamber, the ionic mean free path to the test mass decreases. This should also help us a little on pump-down time. All other settings were identical to what worked well yesterday (see LHO aLOG 38430):
   - clean air flow rate of ~70 [L/min] (or "slm")
   - ion "current" (voltage) occasionally measured by the electrometer with high-amplitude square wave (12Vp amplitude) of +/- 8 [V]
   - pressures inside the TMDS of ~100 [Torr] as measured by the baratron
Attached are the raw notes (but they're not very exciting -- just 4 measurements of the ion "current" during the 1/2 hour discharge cycle).

Based on the current pump-down rate, we expect to perform our third and final cycle around 01:00p PDT today.