Naoki, Sheila

We revisted the alignment shifts of the OMC that we did yesterday morning, (71268) with a cold om2 today.  Yesterday we saw that we were able to reduce the jitter coupling measured by exciting the IMC PZT, but that this didn't improve the peaks caused by ambient jitter in DARM (see Brina's comment).  So, today we didn't bother with the injections on the PZT, but moved the QPD offsets and looked at the jitter peaks in DARM and the coherence with the IMC WFS DC channels.  We weren't able to reduce the jitter peaks by much with om2 cold, we moved both OMC QPDs in both pitch and yaw to explore the alignment space, we found that we could make the jitter peaks very slightly better at the cost of 10% loss of optical gain, or in other parts of the space we started to saturate the suspensions when we moved to where the jitter peaks were very slightly reduced.  None of these slightly reduced peaks gave us jitter as low as we had with hot om2.  We've returned the offsets to the original offsets, found before we turned on the TSAMs.  This has restored the optical gain to what it was before the TSAMs was on.