Sheila, Kiwamu,

This is a follow up of the latest AS90 jump incident reported in 31844.

We think this anomalous behaviour started in this past Wednesday (31804). This time, we looked into some other signals and found elevated noise in SRCL, although we are still unable to localize the issue.

[Time line]

• 5:45 UTC, fully locked
• 6:02 UTC, data evaluation point #1
• 6:17 UTC, AS90 jumped and increased
• 6:30 UTC, data evaluation point #2
• 7:10 UTC, TJ manually disabled SRC1 and steered SRM to a good alignment
• 7:30 UTC, data evaluation point #3
• 9:12 UTC, another manual SRM tweek by Nutsinee

[Some observations]

The symptom is very similar to what was reported in 31804. The POP 90 increased from 13 cnts to 16 cnts. Since the AS diverter was closed, it is hard to say whether there is a jump in AS90 or not. The jump also seems to have caused misalignment in SRC1 as was the case in 31804. The first attachment is trend of some relevant signals. The leftmost vertical line in each column represents the time when the POP90 jumped. The second vertical line represents the time when TJ opened the SRC1 loop and did manual alignment. Similarly to 31804, the POP90 became noisier after the jump. The LO signals in AS36 WFSs didn't show any obvious glitch or abrupt change.

This time we looked at the spectra of the AS A 36 signals and the SRCL error signal. See the second attachment. In each panel, the blue curve is taken before the jump or at evaluation point #1 (see the above list). The green curve is taken right after the jump or at evaluation point #2. Finally the red curve is taken after TJ's fix or at evaluation point #3. I was hoping to see an obvious change in the spectra that might indicate some electronics issue, but the AS 36 signals didn't really show an obvious change as far as the spectra are concerned. However, on the other hand, we found a difference in the SRCL length error signal although this is not easy to interpret. Right after the jump the SRCL noise increased in 3 - 30 Hz by roughly a factor of two. This cannot be explained by the change in the optical gain beucase the increased POP90 should mean a lower optical gain for seinsing SRCL. Another explanation might be a worse A2L coupling contaminating SRCL due to the different spot positions on the SR mirrors.

I was curious to see how the BRSX was doing, so attached is a quick 5 day trend. It seems that it may be slowly ringing down after Jim vistied on Thursday.

TITLE: 11/27 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Travis
CURRENT ENVIRONMENT:
    Wind: 4mph Gusts, 3mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.36 μm/s
QUICK SUMMARY: On our way back up after some issues described in the log below mine.
 

TITLE: 11/26 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: TJ
SHIFT SUMMARY:
LOG:

17:50 Kyle on site checking pumps.

18:01 Patrick to CER

18:05 Robert to EY

19:50 Robert and AnnaMaria to put beam dump in MC Refl, Patrick to CER taking top off of Beckhoff module.

20:30 ECat chassis is fixed.  Start relocking.

23:50 PCal X 5001.3 Hz line turned off.

At the request of Adam Mullavey (via a phone call from Rick), I have turned off the 5001.3Hz PCal line at EndX for some injection work.  I did this by zeroing the amplitude of the line, leaving all other parameters unchanged.  See attached screenshot for setting before I changed them.

In a later email forwarded by Rick, Shivaraj mentions having to change Guardian code to keep these lines off at LLO.  I'm unaware of any such PCal Guardian code at LHO (my guess is that this is due to the fact that LHO doesn't use PCal for locking like LLO does), so made no changes to Guardian.  If someone reading this knows otherwise, please contact myself and the current operator.

We are just starting to do initial alignment after the Beckhoff issue was resolved by Patrick and Richard.  So far, so good.

~0945 - 0955 hrs local -> Kyle R. and Travis S. in and out of LVEA 

Suspected that the backing pump cart's pirani gauge might have increased from its steady, bottomed-out, value of 1.7 x 10-3 torr at the start of the bake to, a now steady, 1.9 x 10-3 torr value -> Closed the O-ring valve at the "hung" turbo's exhaust for several tens of seconds while Travis monitored the pirani reading -> Displayed value remained unchanged while valve closed and after valve opened (should have taken notes - initial value was probably "1.9" all along).  

Temperature survey a little high after yesterday's modest variac increase -> As found today, more like 95C +/- 10C -> Decreased variacs slightly.  

The plan now is to start the temperature step down beginning tomorrow morning such that pump hardware can be removed and PT180 be re-exposed to the site vacuum volume (i.e. return to nominal state) on Tuesday

It appears the problem is either with ISC Common L20, ISC Common M0, or the link between (see attached screenshots). I will go out to the CER and take a look.

Everything looks fine to me, but I'm no expert.  See attached screenshots.

TITLE: 11/26 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Down due to Beckhoff issues
OUTGOING OPERATOR: Nutsinee
CURRENT ENVIRONMENT:
    Wind: 2mph Gusts, 1mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.49 μm/s
QUICK SUMMARY:  Down due to Beckhoff issues per Nutsinee's aLog.  Have contacted Keita and Patrick.  Keita is looking at things remotely and Patrick is on his way to the site.
 

TITLE: 11/26 Owl Shift: 08:00-16:00 UTC (00:00-08:00 PST), all times posted in UTC

STATE of H1: Unknown

INCOMING OPERATOR: Travis

SHIFT SUMMARY: H1 stayed locked most of the shift. Now I'm running into an issue I've never dealt with before. See alog31847 for details. This alog has disappeared magically. See alog31850 (comment below) for details.

LOG:

9:05 Noticed range slowly dropping, out of Observe to adjust SRM P

9:08 Back to Observe

9:12 Noticed that I made it worse, back to commissioning to move SRM P the other way round.

9:16 back to Observe.

13:39 Lockloss

14:24 THE confusing lockloss. Below I copied some of the Verbal Alarm message that might be useful in giving people insight of what's going on. It would be useful to know how long does the code take to loop though all the status of things.

          14:23:16 VIOLIN_MODE_DAMPING2

          14:23:28 TCS CO2 lasers tripped

          14:23:24 ISI HAM6 WD tripped

          14:23:48 ETMX ISI ST1 WD tripped

          14:23:48 ETMX ISI ST2 WD tripped.

          14:24:01 DOWN

TITLE: 11/26 Owl Shift: 08:00-16:00 UTC (00:00-08:00 PST), all times posted in UTC

STATE of H1: Observing at 70.3054Mpc

OUTGOING OPERATOR: TJ

CURRENT ENVIRONMENT: Wind: 4mph Gusts, 3mph 5min avg Primary useism: 0.04 μm/s Secondary useism: 0.62 μm/s

QUICK SUMMARY: TJ had it locked for me.

TITLE: 11/26 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing
INCOMING OPERATOR: Nutsinee
SHIFT SUMMARY: PEM work for the whole shift, broke lock a few times, but recovery was pretty usual. POP90 jumped on me once, but I missed it and didn't notice till Anamaria pointed out the loss of range. I turned off the SCR1 loops and thenmoved SRM back to where it was.

The PEM crew is running the lines from alog31845
LOG:

• 01:21 Lockloss. Possibly PEM inj., but SCR1 Y maybe drifted a bit too much? Not too sure, plots attached.
• 02:28 NLN - Had some annoyances at DRMI but normal other than that.
• 02:47 Lockloss. ETMY HEPI, ISI, AND TMS tripped. PEM crew responsible.
• 03:35 NLN. Had to move TMSX a bit after it tripped to get good ALS powers.
• 04:09 Lockloss. HAM6 ISI tripped. PEM.
• 04:46 NLN. Nothing to note.
• 05:00 Lockloss. ETMY SUS, TMSY, ISIST1&2 tripped. Not too sure of the cause.
• 05:46 NLN. Nothing to note.
• 05:54 PEM crew to LVEA
• 07:00 PEM crew out
• 07:04 Brief CP4 minor alarm, everything looks ok.
• 07:08 SCR1 OFF, I missed POP90 jumping up, but trended and brought it about back.
• 08:06 Observing

Today we shook HEPIs, all chambers, and shook the input and output arm beam tubes at the corner station. A few of the lines in DARM were excited by the BS injections. We left low frequency lines In the  cal line of ETMX L1 (0.3 Hz lenght) and ITMX L1 (0.2 Hz yaw) to produce side bands on certain lines. These lines are considerably smaller than the microseismic peak, so we didnt want them to keep us from going to observation mode.