Reports until 08:09, Tuesday 29 December 2015
LHO General
corey.gray@LIGO.ORG - posted 08:09, Tuesday 29 December 2015 - last comment - 11:12, Tuesday 29 December 2015(24539)
Transition to DAY Shift Update

TITLE:  12/29 DAY Shift:  16:00-00:00UTC (08:00-04:00PDT), all times posted in UTC     

STATE of H1:   NLN hovering sort of above 70Mpc

Outgoing Operator:  Ed

Quick Summary:

Maintenance Tuesday-Lite beginning.  Kissel & I are at the helm.   We were just sort of discussing a gameplan.  Will stay locked as much as possible & also in Observing as much as possible.  A Praxair delivery is due today.  When/if that happens, I can perform a PSL Watchdog Reset (very quick and non-invasive maintenance task).

Kissel mentioned that our ratty range could be due to some MICH coupling into DARM (he saw a glitch on the running MICH live trace when he walked in); he's investigating.

No wind, and useism is about 0.5um/sec at LVEA.

LLO was up for about 90min a while ago (first time in last day+?).  Chatted with William and he also expected a liquid Nitrogen tank delivery.

Comments related to this report
corey.gray@LIGO.ORG - 08:31, Tuesday 29 December 2015 (24540)
Link

ISI Blend status:  

  • 45mHz ON ITMy, ITMx, BS for X&Y
  • 45mHz ON ETMx X & ETMy Y
jeffrey.kissel@LIGO.ORG - 08:46, Tuesday 29 December 2015 (24541)
Link 

My claims are unfounded regarding excess SRCL (or MICH) coupling. See attached -- I show the coherence between the current DELTA L EXTERNAL ASD and that of MICH & SRCL error signals, and one can see no excess coherence between MICH or SRCL to DARM in the frequency region where the red, 70-75 [Mpc] DELTAL ASD is above the gold, ~80 [Mpc] ASD. I'd shot from the hip when I saw the excess noise in the 60 to 200 [Hz] noise, because I've seen poor SRCL subtraction take that shape in the past when we were constantly tuning the subtraction (e.g. LHO aLOGs 19774, 18402). I'll keep looking, but I suspect whatever the problem is, it's what has been happening throughout this entire lock stretch (locked in nominal low-noise since Dec 29 2015 07:54:01 UTC).

EDIT: Also not coherent with the EOM Driver's 45 MHz amplitude noise suppression loop's control signal (H1:LSC-MOD_RF45_AM_CTRL_OUT_DQ) so, it's also NOT "RF45" noise.
Images attached to this comment
gabriele.vajente@LIGO.ORG - 11:12, Tuesday 29 December 2015 (24546)
Link

I ran BruCo on 10 minutes of data starting at 2015-Dec-29 16:14:47 UTC. The full report is available here:

https://ldas-jobs.ligo.caltech.edu/~gabriele.vajente/bruco_1135440904/

Unfortunately, in the region between 70 and 100 Hz, which seems the one thta got worse, there hardly is coherence with any channel.

At lower frequency, one can find the usual coherence with SRCL/MICH signals, but it seems too low to explain any excess of noise.