I have reduced the OMC ASC gain from 0.02 to 0.016, in hopes that this will help reduce the scattered light glitches at low frequency. We'll run like this for an hour or so to see if this has a beneficial effect.
I have accepted the new gain in SDF so that we could go back to Observe, but I have not modified guardian yet.
The beams on the OMC QPDs aren't too close to the edges of the QPDs, although we are pretty solidly off into one of the quadrants of QPD A (see 1st attachment).
Lowering the OMC ASC gain from 0.2 to 0.16 does seem to have lowered the highest frequency that the scattering affects. In the second attachment I have overlayed the 12 hour DMT Omega glitch gram with the OMC ASC gain, and there is a bit of a step down in the width of the glitchy low frequency band. The glitches are still there, just aren't affecting as high a frequency.
If things continue to go well (i.e. the OMC ASC isn't causing problems, which I don't think it will) and the lowering of glitch frequency stays true, we might consider further lowering the OMC ASC gain.
