Lockloss @ 03:42 UTC - link to lockloss tool

M5.5 earthquake out of southern Mexico (seismon lists this as nearby Guatemala). Entered earthquake mode one minute before the lockloss, although peakmon only reached up to around 600 counts.

Ryan S, Ibrahim, Oli, Sheila, Camilla, Mayank

Problem: The ADF_OMC_TRANS_SQZ_ANG (ADF readback of Sqz angle) was not linear with the SQZ angle (~ SQZ-CLF_REFL_RF6_PHASE_PHASEDEG).

What we tried so far?

1. We played with different combinations of ADF_VCXO phase and ADF demod phases to see if we can get linearity between these two channels however it did not work. (See Figure 1)
2. We plotted parametric ADF_I and ADF_Q for various Demod phases. Ideally this curve should be an ellipse centered around (0,0). However the ellipse we got was shifted from (0,0). (Figure 2 part A). { The ellipticity of the ellipse depends on the amount of squeezing and the location on the ellipse determines the squeezing angle}

What we did ?

1. We calculated the required offsets (ADF_OFFSET_I and ADF_OFFSET_Q) so that the ellipse can be centered around zero.
2. We calculated the G (4.5) value from the ellipse and used this normalization constant of ADF_Q to turn the ellipse into a circle.
3. Calculated the new ADF readback of sqz angle values after numerically adjusting the offsets and normalization and verified that it indeed is linear over a wide range of squeezing angle. (It is matches well with squeezing angle, see Figure 3 )   
4. Added all these changes to the model and scanned the RF6 demod phase to verify that the ADF readback values now closely follow the squeezing angle. (see Figure 4) and Figure 5 shows the ADF_I and ADF_Q demod plot (Ideally it should be a circle )
5. We modified the SQZ_ANG_ADJUST.py  (Fig 6):  We found that the ADF_OMC_TRANS_SQZ_ANG = -95 for the optimum Squeezing and added it as the setpoint. The servo locked with these changes .

We may further tweak the parameters to improve the ADF performance.

Following alog 83343 (transmission VS AOI of a mirror that's supposed to be O3 ZM2), Rahul and I did a similar measurement for the old ZM1 for P-pol at 1064nm. Unlike "ZM2 optic", this one looks good.

Currently, proposed layout for POPX TT looks to have the AOI between 30 and 35 deg, and an alternate proposal is somewhat larger than that but smaller than 45 deg. Either way this old ZM1 optic will work.

The first two attachments show the experimental setup. The entire TT assembly was put on a rotational stage. The TT suspension was locked during the measurement.

Before and after the measurements, the power of the beam impinging ZM1 was 293mW and 289mW respectively, so I used 2.9e-1W as the input.

AOI close to but not quite retro-reflection (our reference point) was estimated to be ~1.4deg by measuring the distance (~1+-1/8") between the incoming and the reflected beam ~21" away from the mirror surface: (1+-1/8)/21/2 * 180/pi = 1.4+-0.2 deg. (The reason why it's not set to zero+-0.2deg is because of silly mechanical interference we didn't bother to fix.)

At 45.4deg AOI, the beam might have been very close to the back of (or even getting clipped by) the adjustment screw for the eddy current damping magnet. I wasn't able to see the beam (1.7uW of blob is hard to see for anybody) so it's unclear. At least the beam position on the HR surface looked OK, so if the beam is clipped by the adjustment screw it might be unnecessarily long. I'll have another look with IR sensitive camera on Monday.

FAMIS 26367, last checked in alog83146

Infrequent and erratic motion seen on EX fan 2, as has been noted on past checks. All other fans behaving normally within noise thresholds.

Ryan S, Sheila, Camilla

Ryan found that ISC_LOCK was waiting fo SQZ_MANGER to get to FDS in INJECT_SQUEEZING, but SQZ_MANGER will not get there as is waiting for ISC_LOCK (the SQZ_ANG_SERVO won't start until after OMC_WHITENING). This was wasting time. Made the attached edit and ISC_LOCK moved through INJECT_SQUEEZING much quicker.

TITLE: 03/14 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY:

IFO is in NLN and OBSERVING as of 23:14 UTC (2 min lock!)

A  calm shift with a very successful comissioning period where we were locked for the entire 6 hour comissioning block.

Our 22 hour lock was lost due to an ETM Glitch (lockloss alog 83375).

A summary of comissoning activities (alogs if possible):

1. SQZ: alog 83370 by SQZ Team (Camilla, Sheila, Mayank)

2. OPS: A2L Script alog 83373

3, PEM: Injections + Measurements (Robert)

4. ISC: Modulation Depth Step up/down (Elenna)

LOG:

TITLE: 03/14 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 8mph Gusts, 4mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.29 μm/s
QUICK SUMMARY: H1 just made it back to low noise as of 23:14 UTC after a fully automatic relock with an initial alignment.

• Wind low, microseism steady around 75th percentile
• All other systems nominal

ETM Glitch Lockloss. Relocking now.

During comissioning, I ran a2l script for all. Results and screenshots below.

ETMX P
Initial:  3.23
Final:    3.22
Diff:     -0.01

ETMX Y
Initial:  4.9
Final:    4.95
Diff:     0.05

ETMY P
Initial:  5.52
Final:    5.4
Diff:     -0.12

ETMY Y
Initial:  1.35
Final:    1.4
Diff:     0.05

ITMX P
Initial:  -0.53
Final:    -0.56
Diff:     -0.03

ITMX Y
Initial:  3.21
Final:    3.24
Diff:     0.03

ITMY P
Initial:  0.06
Final:    0.02
Diff:     -0.04

ITMY Y
Initial:  -2.74
Final:    -2.77
Diff:     -0.03

Sheila, Camilla

NLG Measurements (follow 76542):

For 25uW we needed to reduce H1:SQZ-OPO_PZT_1_SCAN_TRIGGER_CHANNEL_1_LEVEL from 0.5 to 0.25

FC2 is misaligned during this dataset. Aimed for 3m30 of data for each point.

In the Mean SQZ data, there was a strange peak around 300Hz, we checked if tis was seeding by moving H1:SQZ-LO_SERVO_SLOWOUTOFS, this made no difference

Fri Mar 14 10:13:51 2025 INFO: Fill completed in 13min 48secs

TITLE: 03/14 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 151Mpc
OUTGOING OPERATOR: Corey
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 4mph Gusts, 0mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.27 μm/s
QUICK SUMMARY:

IFO is in NLN and OBSERVING as of 23:59 UTC (14hr 40 min lock!)

We have planned comissioning today from 6AM - 2PM (though will stay in OBSERVING until a comissioner shows up).

TITLE: 03/14 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 147Mpc
INCOMING OPERATOR: Corey
SHIFT SUMMARY: Currrently Observing at 148Mpc and have been Locked for 5 hours. The range is still low and fluctuating a bit, but it's not as bad as it was before I made the changes to the multiple phases (83367). Secondary microseeism is going back down, and the wind is low.
LOG:

23:30UTC Relocking

23:50 NOMINAL_LOW_NOISE
    - Ran SQZ ANG ADJUST to check if the SQZ servo was in a location to pull the ADF phase away
23:59 Observing

02:55 Out of Observing to check sqz angle
    - Ran SQZ ANG ADJUST and had to adjust some phases (83367)

03:13 Back into Observing

We are Observing at 150Mpc and have been Locked for 4 hours.

We just got back into Observing after I took us out to touch up some sqz phases. This morning Camilla and Sheila had found (83350) that the SQZ servo was pulling the ADF phase away and causing large range drops. The same thing also happened the lock after that.

When we first got to NOMINAL_LOW_NOISE, I tried running SQZ ANG ADJUST to check if we were in a spot where the ADF phase would end up getting pulled away. At the location where the squeezing was best, the ADF sqz angle was pretty good, and the demod error was near 0 (ndscope1). I didn't adjust anything because of this, just went back into FDS and then into Observing. I planned on monitoring the ADF phase angle and then do these tests again once we were thermalized.

Over the course of thermalization, the same issue with the ADF phase was happening, although luckily the servo wasn't taking the phase in circles like it had been doing the previous couple of locks (ndscope2). Once we were thermalized, I took us out of Observing and ran SQZ ANG ADJUST. From that I saw that the best location for the sqz phase was now very close to a turning point (ndscope3). To move away from this location, I adjusted SQZ-ADF_VCXO_PLL_PHASE from 25 down to 10, and then adjusted SQZ-ADF_OMC_TRANS_PHASE from -107 to -117 to get SQZ-CLF_REFL_RF6_PHASE_PHASEDEG to oscillate around 0. The yellow BLRMS looks a lot better now and our range has gone up by 10Mpc, but my changes did make the purple BLRMS worse by a bit (ndscope4, ndscope5). I accepted the phase changes in SDF and we went back into Observing (SDF diffs).

Janos, Gerardo, Dave:

The slope trip level for some LVEA gauges was reduced from 1.0e-10Torr to 3.0e-12Torr such that if an event similar to this morning were to happen again VACSTAT would alarm on it.

Trending the SLOPE channels over the past week showed that BSC3's gauge (PT132) cannot be lowered without causing many false positive alarms. Attachments show trend and which gauges now have the lower trip level.

TITLE: 03/13 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Oli
SHIFT SUMMARY: Calibration and commissioning time this morning, but we have also been struggling a bit with relocking. We aren't entirely sure what particular problem is causing the lock losses on acquisition, but the elevated wind and useism aren't helping. We are now on DC readout though, so we're making progress.
LOG:

• 1559 Lock loss - 83351
  • Since this was during commissioning time, we did some ALS linearization testing on the way up (83357).
• 2012 Observing
• 2132 Lock loss - 83360
  • Recovery has been a bit of a struggle. ALS hasn't been staying locked, perhaps the DARM tramp that Sheila put in wasn't working, so we put the tramp back to 5 from 2. We also were losing lock at other various places, so we aren't too sure what the issue is yet. The wind and useism are both elevated, so perhaps this is factoring in.

TITLE: 03/13 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 25mph Gusts, 16mph 3min avg
    Primary useism: 0.06 μm/s
    Secondary useism: 0.34 μm/s
QUICK SUMMARY:

At ENGAGE_ASC_FOR_FULL_IFO and working on relocking with lots of lower state locklosses. These seem to be due to various causes, including high-ish winds& gusts. Secondary microseism is also a bit elevated.

We had a vacuum glitch in the LVEA at 01:57 Thu 13mar2025 PDT which was coincident with a lockloss. The glitch was below VACSTAT's alarm levels by an order of magnitude, so no VACSTAT alert was issued.

The glitch is seen in most LVEA gauges, and took about 10 minutes to pump down.

Attached plots show a sample of LVEA gauges, the VACSTAT channels for LY, and the ISC_LOCK lockloss.

I have recently reported that the “mystery” beam on the spool piece wall near HAM3 was coming from the direction of ITMX (82252). To further this investigation, I started photographing the area around the ITMs and BS as best I coluld through our viewports (there is not a good view towards HAM3).  I found several unexpected distributions of light in the vertex:

1. 20 degree conical annular beams from ITMs

Both ITMX/CPX (Figure 1) and ITMY/CPY (Figure 3) cast an expanding annular “beam” towards the BS with a cone half angle of roughly 20 degrees from the main beam. My best guess is that it is produced by arm cavity light hitting the bevel of the ITMs (see cartoon in Figure 1). A good test of this would be to install the new test mass cage baffles at one or more of the ITMs at LLO (presuming Anamaria finds this beam at LLO) this upcoming break. The baffle should hide the bevel and eliminate the ring of light.

2. 45 degree conical annular beams from BS

The BS appears to cast an expanding annular “beam” with a cone half angle of 45 degrees, centered around the -X, -Y direction (Figure 2), and likely another annular beam, also with a half angle of 45 degrees, centered around  the  -X, +Y direction (evidence in Figure 3). I tried to find a geometry where the bevels were also the source of these beams but didn’t. My best guess is that the annular cone is produced by reflections of light from PR3 and the ITMs off of the inner surface of the circular cage around the BS, or the inside surface of the circular barrel of the BS itself (see drawings on third page of Figure 2). 

3. Reflection of BS in ITM elliptical baffles likely visible at ITMY and HAM3

The BS beam spot is reflected towards ITMY by the slanted piece of the ITMX elliptical baffle (Figure 3). While the actual beam is not reflected towards ITMY (it isn’t clipped), the baffle reflects light towards ITMY that is scattered out of the main beam by only a few degrees.