Sheila, Elenna, Louis, Ryan Short, Jenne, Camilla,
Summary: We are still struggling with DRMI mode hopping, when we get past that we are struggling with the first steps of the CARM offset reduction. We do have some initial alignment ASC working.
- Ryan ran initial alignment and DRMI locked right away, with POP18 lower than on Friday (max 140 counts on I ERR DQ)
- lost lock once when the mode hoping offset came on, the next time while I was trying to measure TR_CARM
- We moved SR3 pitch so that the oplev agreed with what it was before turning the heater on (-1 in pitch), which is also closer to where it was inO4 according to the optical lever (0), reran SRY alignment manually. In SRY, AS AIR sum was at 4920 counts, improved compared to 91957, both before and after the SR3 move.
- We commented out the line that turns off the mode hoping offset in ISC_DRMI zero 3f offsets.
- Measured MC2 crossover in START_TR_CARM, first attachment. It seems like we need to reduce the MCL gain by a factor of 2. We were able to reduce the TR_CARM Offset from -0.5 to -0.8, which is slightly better than other attempts where we couldn’t go higher than -0.7. After we lost lock Elenna measured IMC MCL gain, it matched the reference.
- Elenna edited ISC_DRMI guardian to have the BS oplev damping (which is running on the wit sensor) to only disengage if MICH ASC is on, so making use of the use_[PRMI/DRMI]_ASC flag in lscparams
- Louis moved PR3 according to M3 osems (pr3.png)
- On Friday, PR3 suspensions jumped for some reason at 1475005715. There was a jump that was seen directly in PR3 at all stages (P, Y, and L). After the jump, all three stages of the PR3 suspension were sitting at different positions, according to the osems. About 18 minutes after the glitch, Corey moved PR3 back to the pre-jump positions according to the top mass osems.
- Today it was recognized by Sheila that the POPAIR_B buildups were lower than what was seen on Friday (before the suspension jump on PR3).
- I (Louis) noticed that the position reported by the top mass didn’t agree with that of the bottom mass (or M2). Louis suggested that we rely more on the bottom stage osems and move PR3 back according to M3 osems instead.
- Moving PR3 back to the M3 osem positions made the ALS Comm beatnote worse compared to when PR3 was aligned to the top mass osems. On the other hand, at the current position the beatnote power level matches what we had before the suspension glitch on Friday. So even though the comm beatnote is lower at the current alignment, we are leaving it as-is because it seems to better resemble the alignment we had on Friday before the suspension glitch.
- ndscope template with markers set at the glitch and when Louis moved PR3 back today at ~louis.dartez/scopes/pr3_osems.yaml
- After moving PR3, we did initial alignment. We paused at input align, Elenna phased refl wfs using a excitation in LSC XARM (6 screenshots attached of the phasing, sdf). While she did that Sheila closed the Input align loops, with negative signs in INP1 P +Y, which is AS B 45. We subtracted 180 degrees from all quadrants of AS B 45MHz (SDF).
- OPSINFO: We believe that next time someone does initial alignment, we should be able to run WFS for input align and PRC, SRC align, which we did run today.
- Must still do MICH dark by hand
- The strt_TR_CARM state failed, which you can see from the arm power fluctuating wildly. To recover from this,
- zero the REFLBIAS gain,
- open the ALS COMM VCO screen (ALSO overview, VCO next to COMM PD), turn the servo to int and on (H1:ALS-C_COMM_VCO_CONTROLS_ENABLE), and set the H1:ALS-C_COMM_VCO_CONTROLS_SETFREQUENCYOFFSET to something like -2000, wait for the arm flashes to go away.
- Then you can manual to PREP_TR_CARM, try start_TR_CARM again
- We’ve tried setting the MCL gain to 150 (rather than the usual 300). We tried skipping the step where we turn off FM4 in REFLBIAS and reducing the gain in the REFL servo in2. We also tried a few more iterations of upping the gain by a factor of three, then stepping offsets. It seems like there are some glitches that always get worse when we ramp down the ALS gain, and sometimes also when we reduce the CARM offset.
- We are sort of centered on TMS QPD B for both arms.
- Buildups today:
- PRMI POP18 is 113
- DRMI POP18 is 134, POP90 is 22
- These buildups are lower than Friday but were not improved during our PR3 moves