Reports until 19:29, Monday 15 September 2025
H1 ISC
ibrahim.abouelfettouh@LIGO.ORG - posted 19:29, Monday 15 September 2025 (86951)
Locking: Getting LASER_NOISE_SUPPRESSION

Ibrahim, Elenna, Jenne, Ryan S

We made it to LASER_NOISE_SUPPRESSION!

Here's how we got here again and here's what we're monitoring

After much needed help from Ryan S, Elenna and Jenne in initial alignment (manual initial alignment needed), we managed to get back to CARM_5_PICOMETERS but encountered the same issues with an SRM ringup upn getting to RESONANCE, which caused a Lockloss.

Elenna guided me through the following combination of steps tried this morning:

1. Get to CARM_5_PICOMETERS

2. Set TR_CARM_OFFSET to -52

3. Set the REFLAIR_B_RF27 I PRCL matrix to 1.6*(value-it's-at). Press LOAD MATRIX. This is reached by going to LSC->LSC_OVERVIEW->AIR3F (under input matrices area on left of screen, you want to look for REFLAIR_B_RF27 on the left).

4. Continue locking - SRM rang up as before and saturated once but with the new gain, it was enough to not cause a LL.

This worked, and now we're at OMC_WHITENING with high violins (so understandable, sorry fibers).

Now, I'm monitoring H1:IMC-REFL_DC_OUT16 and watching for an increase in power, which is bad. We've been at 63W (the new 60) for 18 minutes - here's a plot of that.

I don't know the calibration, but CDS OVERVIEW is reading out 147MPc

Images attached to this report