patrick.meyers@LIGO.ORG - posted 17:58, Monday 07 November 2016 - last comment - 09:51, Sunday 13 November 2016(31297)
Strong 11 Hz comb during November 5th Lock
Ansel Neunzert, Pat Meyers
We see a strong 11+/- 0.0001 Hz comb show up in DARM in the lock on November 5th [first harmonic in plot: DARM_11_5_2016.png ]. It is very strongly coherent with quite a few corner station channels including magnetometers, microphones, and radio receiver [see plot 2, for example].
It looks like this comb shows up in the CS magnetometers around 01:00 - 02:00 UTC on Saturday, November 5th [see plots 3-6, red dots indicate n*11.0Hz] There are links to interactive plots below, as well.
We don't think this is related to the PEM injections, which took place later in the day, but there was some HWS work around that time (although it sounds like that is an unlikely source).
There's no evidence of this comb in the lock from today (November 7th).
——————— stamp-pem results —————————
[Coherence * Number of averages is color, rows are channels, columns are 0.1 Hz frequency bins]
https://ldas-jobs.ligo-wa.caltech.edu/~meyers/stamppemtest/HTML/day/20161105/Physical%20Environment%20Monitoring:%20Magnetometers.html
https://ldas-jobs.ligo-wa.caltech.edu/~meyers/stamppemtest//HTML/day/20161105/Physical%20Environment%20Monitoring:%20Low%20frequency%20microphones.html
https://ldas-jobs.ligo-wa.caltech.edu/~meyers/stamppemtest//HTML/day/20161105/Physical%20Environment%20Monitoring:%20Radio%20frequency%20recievers.html
————————— Interactive plots —————————————
DARM for all of 11/5: https://ldas-jobs.ligo-wa.caltech.edu/~aneunzert/preER10combs/preER10_2016-11-06_fscans/H1:LSC-DARM_OUT_DQ.html
11/4 22:00 - nothing https://ldas-jobs.ligo-wa.caltech.edu/~aneunzert/comb_plots/elevenHzcombCheck_2016-11-04-22-00-00_0p5-hrs/H1:PEM-CS_MAG_EBAY_LSCRACK_X_DQ.html
11/5 01:00 - very slight traces? maybe? https://ldas-jobs.ligo-wa.caltech.edu/~aneunzert/comb_plots/elevenHzcombCheck_2016-11-05-01-00-00_0p5-hrs/H1:PEM-CS_MAG_EBAY_LSCRACK_X_DQ.html
11/5 02:00 - very strong https://ldas-jobs.ligo-wa.caltech.edu/~aneunzert/comb_plots/elevenHzcombCheck_2016-11-05-02-00-00_0p5-hrs/H1:PEM-CS_MAG_EBAY_LSCRACK_X_DQ.html
Images attached to this report
Comments related to this report
Coherence tool results from Oct.31 to Nov.7
The 11Hz comb is very pervasive. It is found in 255 channels in the second week Oct.31 - Nov.7. In some of the channels, the comb only has the lower 3 or 4 harmonics. The results are posted here:
https://ldas-jobs.ligo-wa.caltech.edu/~duo.tao/O2_lines/index.html