aLIGO LHO Logbook

H1 SUS

michael.landry@LIGO.ORG - posted 18:36, Friday 02 March 2012 - last comment - 06:41, Tuesday 06 March 2012(2352)

ITMY fiber break in BSC8

Today SUS testers noted ITMY M0 top OSEM sensors railed (see Kissel/Barton alog entries below, 07:47 today).  Concerned for the state of the ITMY monolithic fibers, we pulled viewport covers to inspect the quad.  While the view of the TM was largely occulted by the AOS ACB, we could see evidence of fiber breakage on the floor in the form of glass shards.  The ISI/SUS/HEPI underwent a major and sustained actuation.  Investigations are underway to determine the cause.  

We will open BSC8 early next week to begin repair work.

-Landry/Bland/Sadecki

Comments related to this report

fabrice.matichard@LIGO.ORG - 22:27, Friday 02 March 2012 (2354)

Link

We tried to extract a few notable events:

Thursday March 01, 2012

07:40 am PT: 
- The SEI watch dogs is armed 
- The SUS watch dogs is  on State 1 = "OSEM DC RMS Triggered" (see page 4)
- We start seeing more motion in the HEPI and ISI sensors, apparently driven by the beginning of the activity at the observatory

11:25 am PT: We see more motion. The ISI watchdogs trip.

11:47 am PT: huge motion starts being visible on the OSEMS (page 1), HEPI (page 5) and ISI signals (page 6 & 8). It will last until 17:28 PT.

11:58  am PT: The Quad watch dog reaches State 2 "OSEM AC RMS Triggered". (see page 4)

12:24: the ISI real time controller is shut down to recompile the model. It's apparently unsignificant, but we wanted to report this detail.

12:41 pm PT: OSEMS signals suddenly goes to 0. This is apparently when the fiber brakes. (see page 1 to 3)

17:28 PT: the huge motion visible in the HEPI and ISI sensors suddenly stops (page 7)

No other similar peak of activity was visible in the past 7 days (see page 11)


Main preliminary comments:
- there was no drive on HEPI (actuators are being flushed).
- ISI and Quad watchdogs are tripped long before the fibers broke
- the ISI real time controller was turned down before the fibers broke
- unusually high motions started at 11:47am PT and continued till 17:28 PT.

-Fabrice/Hugo/Vincent

Non-image files attached to this comment

Signalstrends2.pdf

jeffrey.kissel@LIGO.ORG - 06:41, Tuesday 06 March 2012 (2363)

Link

Just so people don't have to convert time zones for future data mining:

2012-03-01 ~08:00a PT = 2012-03-01 ~1600 UTC = 1014652815 = Morning LVEA activity is on-going

2012-03-01 11:47a PT = 2012-03-01 1947 UTC = 1014666435 = Huge motion starts

2012-03-01 11:58a PT = 2012-03-01 1958 UTC = 1014667095 = QUAD WD trips, AC Coupled WD

2012-03-01 12:41p PT = 2012-03-01 2041 UTC = 1014669675 = Fiber break

2012-03-01 17:28p PT = 2012-03-02 0528 UTC = 1014701295 = Excitation Stops