Reports until 12:04, Monday 09 October 2023
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jenne.driggers@LIGO.ORG - posted 12:04, Monday 09 October 2023 - last comment - 14:28, Monday 09 October 2023(73345)
LSC FF using ETMY PUM

[Camilla, Jenne]

Some belated notes about trying LSC FF back on Sept 21st, as well as notes on measurements taken today for retuning the LSC FF using ETMY PUM.

LSC FF with ITM PUM did not work when I tried it on 21Sept2023 (turning on MICH FF worked okay, but turning on SRCL FF killed the lock.  We have seen this before in years past at LHO that we cannot use SRCL FF with the ITMs, likely due to a parasitic loop). The measurements and fits for that were in alog 72862

Measurement for MICH FF using ETMY PUM taken 20 Sept 2023 (I forgot to alog).  Lost lock trying to gather SRCL FF data at that time.  Gabriele fit the MICH FF data and gave us a filter (below, and attached).

Camilla and I tried that filter from September:

Measuring MICH and SRCL FF, while still using EY PUM:

 

MICH filter using ETMY PUM from 20 Sept 2023, plotted in attachment: zpk([-8.392330076183118+i*49.39248514742469;-8.392330076183118-i*49.39248514742469;-1.046997552323544+i*62.74012764734476;-1.046997552323544-i*62.74012764734476;-0.195079334716182+i*111.0307750783754;-0.195079334716182-i*111.0307750783754;-67.32125480645517+i*108.7955724988948;-67.32125480645517-i*108.7955724988948;-0.7011570088542948+i*401.6350155234317;-0.7011570088542948-i*401.6350155234317;-2.779238087179218+i*518.2808819075473;-2.779238087179218-i*518.2808819075473;-317.3841576035709+i*1079.288485296243;-317.3841576035709-i*1079.288485296243;-178.8519649481057+i*1320.885890800788;-178.8519649481057-i*1320.885890800788;49.42179558079376;-126.1091578653822;-342.6998780810434;-387.3921871872612],[-6.612825148760598+i*18.03485413750199;-6.612825148760598-i*18.03485413750199;-10.51113766874398+i*51.44409984903976;-10.51113766874398-i*51.44409984903976;-1.193259418463134+i*62.71361669508964;-1.193259418463134-i*62.71361669508964;-0.184848231243519+i*111.3871852754391;-0.184848231243519-i*111.3871852754391;-111.7020413312252+i*111.668875814675;-111.7020413312252-i*111.668875814675;-0.7097877123317881+i*401.6301823509122;-0.7097877123317881-i*401.6301823509122;-2.787645529701059+i*518.2913243267907;-2.787645529701059-i*518.2913243267907;-335.0087359797044+i*492.7511937802536;-335.0087359797062-i*492.7511937802536;-227.3099122149132+i*1161.919607907957;-227.3099122149132-i*1161.919607907957;-100.9775239200197+i*1321.691603918431;-100.9775239200197-i*1321.691603918431],-69.94521247458729)

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Comments related to this report
camilla.compton@LIGO.ORG - 14:28, Monday 09 October 2023 (73348)
Gabriele pointed out it would be too confusing to iteratively change the FF using a MICH/SRCL measurement with the current ETMX feedforward filters on.
I tried to retake the MICH_excitaion.xml and SRCL_excitations.xml measurements without FF but misunderstood and left the FF's on with filters off, the SRCL measurement caused a lockloss.
We will aim to continue FF retuning on Wednesday. 

Attaching the plot of MICH FF currently (pink), with Jenne's 20 September ETMY PUM filter engaged (light blue) and the last time we had recently tuned the FF (green).

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