Reports until 16:44, Thursday 23 May 2024
H1 SUS (ISC, SUS)
joshua.freed@LIGO.ORG - posted 16:44, Thursday 23 May 2024 (78006)
Updated ITMX damping contributions to DARM

J. Freed, J. Kissel

 

Today we did damping loop injections on all 6 BOSEMs on the ITMX. Which what partially done by anamaria previously for half of them and we found simmilar coupling effects around the 14Hz range.

Changes from Anamaria:

We could not see any noticeable coupling at a gain of 600 for the BOSEMs, very likely due to the increased noise at low frequency today. As such, for this test we incresed the gain to 750. At this level saw coupling from the ITMX. We also increased the range of interest down to 8Hz (We did not change the range of the bandpass filter today, just the plot range)  as we saw some noise coupling on some sensors below 10Hz.

Plots, code, and text files of flagged results can be found in /ligo/home/joshua.freed/20240523/Scripts

While the dtt's can be found in /ligo/home/joshua.freed/20240523/Data

All sensors of ITMX showed some coupling, with every sensor showing coupling in different ranges around 14Hz. With the F1-3 being narrow band around 14Hz, and the LF, RT, SD having a larger range from 10-14Hz. Also noting, F1, LF, RT had more than one instance of coupling in a small range around 92Hz, which Anamaria's F1 data also shows.

itmx_f1_20240523.png shows an example plot of the coupling with the grey dots on the bottom plot being the Estimated upper limit of the ambiant noise and the blue dots are the actual measured noise that are flagged

itmx_f1_ana_20240502.png Shows Anamaria plot for comparison

20240523_Measurment_notes.txt Are notes taken during the process
 
Edit notes (Joshua):
As a quick and dirty offline analysis, I increased the FFT length from 8 to 128 and lowered frequency range of the data we had colected to 91Hz-94Hz. increased the duration from 64 to 128 since we took data for that long
F1, LF, RT all had a large coupling at 92.46Hz With smaller peaks around that value
F1 had a smaller peak at 92.32Hz
LF had a smaller peak at 92.41Hz
RT had a smaller peak at 92.51Hz
 
itmx_F1_92Hz_20240523.png is a close up of this 92.46Hz line from F1
 

 

 

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