gabriele.vajente@LIGO.ORG - posted 15:34, Monday 17 April 2023 - last comment - 19:01, Monday 17 April 2023(68746)
Ring Heater Change
Elenna, Evan, Gabriele
We're starting from Dan's observations summarized in 68664 and comments:
- The lower frequency peak in DARM is ETMY, the higher frequency peak is ETMX
- We were at ETMX = 1.3 W, ETMY = 1.0 W
- From the plot in Dan's entry we estimate that both peaks are moving down when the RH power is increased, at a rate of -150 Hz/W (assuming a linear behavior, not quite true since changing the RH will also change the circulating power
- At ETMX=1.3W and ETMY=1.0W, the peaks are separated by 120 Hz
So to match the two peaks, we would need to change the RH differentially by 0.4 W each:
- ETMX should go up by 0.4 W, to 1.7 W
- ETMY should go down by 0.4 W to 0.6 W
At about 2:38pm local time we move ETMX and ETY RH by HALF of the above step, to see if we're going in a good direction. Now ETMX is set to 1.5 W and ETMY is set to 0.8 W
Images attached to this report
Comments related to this report
We have had two locklosses from the 80.3 kHz PI, however just based on the high frequency DARM spectrum it appears that we are going in the correct direction. I have increased ETMX to 1.7 W and decreased ETMY to 0.6 W as we previous decided.