Craig, Georgia We tried to get back to high power tonight, but had three sudden death locklosses in CARM_TO_ANALOG. Georgia tracked it down to ramping the SumNode A IN2 gain from 0 dB to 23 dB. We took a bunch of CARM OLG measurements, and found that at 23 dB, we would put the CARM UGF directly on a notch. We lowered the max SumNode A IN2 gain from 23 to 17 dB in the guardian state, giving a UGF of 9 kHz. We also noticed that the compensation filter on the LSC servo board (LSC-REFL_SERVO_COMCOMP) turn-on was still commented out in this state, which probably allowed the 1 Hz CARM oscillation we saw today. We left it commented in guardian since we got through the state by hand.
We powered up again to 20 W after going through the CARM_TO_ANALOG state by hand.
We sat at 10 W for 30 mins and tried to run the A2L script, but suspect the gains were too low as we did not see the 20Hz lines in DARM (the ADS CLK_GAIN was 300, and we did turn the A2L inputs on at the drivealign matrix).
We sat at 16 W for ~30 mins and played around with the CO2 settings. Accidentally set CO2 X to 100 mW and CO2Y to 300 mW initially (instead of the other way around), this possibly made things a bit worse on RF18. Eventually set them both to 0W.
First attached screenshot is a grid of diagnostics (RF18, arm transmission, input power, CO2 power, HWS spherical power) for the first 20W power up Sheila talks about earlier this evening, second attachment is for our second power up. Note that RF18 at 10 W stabilised at a lower level with the second lock (suboptimal CO2 settings).
Changed ISC_LOCK guardian code to reflect the new early shuttering of ALS:
State Old Number New Number
PARK_ALS_VCO 451 306
SHUTTER_ALS 452 307
CARM_OFFSET_REDUCTION 306 308
CARM_5_PICOMETERS 307 309
From the simulation numbers on the TCS page, we expect about 17.3 udiopters in lensing for ITMY as seen on the Hartmann sensors= when powering up from 2 watts to 10 watts which starts to get there before turning down the CO2 lasers so maybe the estimate of the absorption isn't that far off. What is interesting is that the Hartmann spherical power eventually reaches close to the original lens that was seen before any power up happened but at this point, the CO2 lasers are off. With the decay of pop18 as a function of power up, we might want to load a bit more power onto the ring heaters in order to reach 25 Watts without losing too much PRC gain.
During the power up, the ITMX Hartmann sensor got a very large kick which we're trying to hunt down now so the data is very hard to interpret.
