aLIGO LHO Logbook

H1 DetChar (DetChar)

jacob.broida@LIGO.ORG - posted 18:20, Saturday 07 November 2015 - last comment - 01:10, Sunday 08 November 2015(23197)

Intense Noise in the Omiscans on Nov. 4

In the omiscans for the top 10 BBH/BNS triggers at the Hanford detector, there were three times that were startlingly noisy. The first can be seen here in the CALIB_STRAIN channel, with a good glitch correspondence picked out in the auxiliary channels:

https://ldas-jobs.ligo-wa.caltech.edu/~jacob.broida/Nov4/BBH/GW/1130687680/
https://ldas-jobs.ligo-wa.caltech.edu/~jacob.broida/Nov4/BBH/1130687680/#H1:ASC-REFL_A_RF45_Q_PIT_OUT_DQ

A quick look at the other auxiliary channels shows an unusual amount of strong noise. The following two scans, however, went even more haywire:

https://ldas-jobs.ligo-wa.caltech.edu/~jacob.broida/Nov4/BBH/GW/1130662168/
https://ldas-jobs.ligo-wa.caltech.edu/~jacob.broida/Nov4/BBH/1130662168/

https://ldas-jobs.ligo-wa.caltech.edu/~jacob.broida/Nov4/BNS/GW/1130662171/
https://ldas-jobs.ligo-wa.caltech.edu/~jacob.broida/Nov4/BNS/1130662171/

As of yet we are still unsure about the cause of all this noise.

Comments related to this report

andrew.lundgren@LIGO.ORG - 01:10, Sunday 08 November 2015 (23203)

Link

These are caused by the known problem with the RF45 modulation. The clue is in the behavior of all the RF45 channels, but the decisive diagnostic is a scan of H1:LSC-MOD_RF45_AM_CTRL_OUT_DQ. This channel should normally be just noise, but will have bursts matching DARM when this problem occurs.

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