Reports until 14:37, Thursday 20 February 2025
H1 SUS (SUS)
rahul.kumar@LIGO.ORG - posted 14:37, Thursday 20 February 2025 - last comment - 16:24, Thursday 20 February 2025(82940)
Violin mode damping- new settings for ITMY 05/06

TJ, Rahul

ITMY mode 05 and mode 06 have been rung-up since morning and TJ and I have tried several settings to bring them down. The settings which is currently working is listed below in bold font,

New settings for ITMY 05/06 (not yet committed to lscparams file):-

FM5 + FM6 + FM10 Gain 0.01 (phase -60 degrees)

The other settings which I unsuccessfully tried as follows,

-60deg phase -0.01 gain - increase

zero phase -0.01 gain - increase

+30degree phase -0.01 gain - increase

Similarly TJ efforts (from morning to noon) are also given below,

Settings tried for this lock below. There was commissioning going on during this time, so I worry that a few of the ones I tried were made worse by measurements.

Phase, gain - result 

-30deg , -0.01 - Slow increase 

-60deg. -0.01 - Slow increase 

-90deg, +0.01 - very slow increase 

+30deg, +0.01 - no increase, no decrease 

+60deg, +0.01 - maybe no increase or decrease? 

Commissioning measurement might have confused this one 0deg, +0.01 - increased

Images attached to this report
Comments related to this report
rahul.kumar@LIGO.ORG - 14:52, Thursday 20 February 2025 (82941)

Looks like IY05 is now increasing (as per narrow filter, broad filter shows decreasing) and mode 06 is decreasing. Since mode 06 is higher than mode 05, I will let the current settings damp it for now.

rahul.kumar@LIGO.ORG - 16:24, Thursday 20 February 2025 (82947)

Current damping using FM6 + FM7 + FM10 Gain 0.01 (-30degree phase) - not sure if this is working yet. Will keep an eye on it tonight.