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Reports until 15:45, Thursday 19 January 2023
H1 SQZ
victoriaa.xu@LIGO.ORG - posted 15:45, Thursday 19 January 2023 - last comment - 22:37, Friday 20 January 2023(66884)
sqz loops

Daniel, Craig, Dhruva, Vicky

Took some TFs and in-loop spectra of the CLF and LO loops today.

Doing this phase noise investigation because from Dhruva's SQZ alignments yesterday, LHO:66877, the "LO Loops Adjusted" meant we 1) increased common boost several dB, 2) turned off all LO_OMC boosts, and gained ~0.5 dB SQZ (140/140 lime green vs 140/140 dark purple from 66877). However, this meant we had NO CMB boosts in the LO_OMC or CLF servos! Making their transfer functions totally flat? So, if this is giving us more sqz, is turning off all boosts giving us somehow an improved phase noise scenario? Or something else? Notable changes from last time we ran SQZ TF's (Aug 2022, 64581) are we have lower CLF power now, so maybe sensing noise related? Craig is helping us with his SR785 scripts, we are documenting our usage the code here for future reference.

CLF_RF6    RFMON @ -29.2.

CLF_tf . calibration = 660mVpk-pk / (2 rad) = 330mV/rad. +27dB common, +6dB fast, 1 and 2 common boosts

clf spectrum.txt : saved with multiple FFT bin widths, 400 Hz, 1.6kHz, 25kHz, 100kHz

OMC_TRANS_RF3    RFMON @ -18.5.

LO_tf . calibration = 500mVpk-pk / (2rad) = 250mV/rad. -2dB common, +0dB fast, 1 and 2 common boosts

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Using Craig's psl SR785 scripts to take these measurements. See LHO:64204 to get started.

Had to do this once to get the "quick_psd" function working on my cds account: conda init bash

To get noise spectrum data at many BWs:

To view a single .txt data file:

To stitch spectra from many BWs together:

To check stitched results:

 

For example, with our morning data we manually collected, I did:

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daniel.sigg@LIGO.ORG - 10:10, Friday 20 January 2023 (66913)

The integrated RMS curves suffer from a math error and are wrong.

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