Alexa, Evan, Sheila, Kiwamu, Elli, Daniel
Today we made several small improvements
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We edited the guardian so that it reliably gets us to a CARM offset of approximately 10 pm, (TR_CARM = 30)
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We are now using an OPLev servo at DC on PR3 to help with the alingment drifts we see everytime we get some decent power build up in the IFO.
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We noticed that the SRCL and MICH gains needed adjsutment. At a TR CARM offset of 30 we reduce the SRCL gain by about 50%, from -45 to -26, and increase the MICH gain by a factor of 3 to 6
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We attempted to use the MICH WFS, they worked well without the arms, we used the highbandwidth configuration. We tried the CARM offset reduction with these two loops on, the alingment indeed stayed better, but we also lost lock suddenly. Elli saw in at least one of these lock losses that the MICH WFS were oscillating, so we are now leaving them off. It would probably be worthwhile to try the low bandwidth version.
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We went to ISCT6, replaced the 2 0.5 ND filters with an absorptive ND 1.0 filter and checked the centering on ASAIR A. This turned out to be a different level of attenuation than we had with the 2 ND 0.5s so we changed the gain in ASAIR_A_RF45_I and Q to 5.4
We then made several attempts to transition off of TR_CARM. As on friday, we are able to get to low CARM offsets, and sit there stably, but haven't been able to turn off TR_CARM yet. We found that we could sit at about 5 pm (TR CARM = -39) stably with just TR_CARM on.
Transition attempts:
At -36 in TR_CARM, engage analog REFLAIR 9 with 40 dB total gain on summing junction and CM board.
At -36. engage REFLAIR9 with and offset of -1.8, tried turning off FM 9 (the complex pole compensation) in TR_CARM. Lost lock at 7:23:45
We've had trouble engaging the DHARD WFS with the opposite sign at the small CARM offsets tonight, which on Friday seemed like it was key to being stable at low offsets.
At one point we also tried transitioning at a farther offset. If I remember correcly, the CARM offset was about -25. This also failed.