aLIGO LHO Logbook

H1 ISC - Comment to ETMX ALS issues maybe caused by issues with ETMX L1 LL Output

oli.patane@ligo.org — Mon, 24 Aug 2026 18:10:33 -0700

Author: oli.patane@ligo.org

Report ID: 91655

Fil, Oli

We did a few tests at EX to try and figure out what was wrong with the ETMX L1 LL osem. We couldn't find anything wrong, but were able to rule out basically(?) everything outside of chamber. Tomorrow Fil will be checking the resistances of the L1 osems.

The LL channel generally seems to be moving a lot less than it should be(ndscope6). It also sometimes doesn't really line up with the normal breathing frequency of the other L1 osems (I had seen it happening earlier but wasn't able to find an example), but other times it does seem to breathe at the same frequency, albiet still moving a much smaller amount.

COILOUTF OFFSET tests
If you turn on smaller offsets (5,000 counts) in L1 COILOUTF, the UL, UR, and LR OSEMINF OUT values would react to each other's offsets, but LL would not react to their offsets and they would not react to an LL offset(ndscope1). If you put a larger (~50,000 counts) offset into COILOUTF osems, we found that sometimes LL would only react a tiny bit (hundredths of a micron) to the other osems' offsets, and it would either react a tiny bit to its own offsets, or it would move about 8 um. One of the times that we put a large offset into LL, it barely moved for over 3.5s before suddenly moving the entire 8 um in 1 second(alltraces,zoomedin). It was very strange (almost like it was stuck???????).

Coil driver to satamp voltage
At the ETMX L1 coil driver (SUS-C1 U29), Fil put a breakout board in the Coil Out to Sat path. Connecting to each channel, we turned on an offset in the COILOUTF filter bank for that channel and monitored the voltage going out to the satamp. Everything made sense - when there was an offset in the measured sensor, we saw a voltage. When there was no offset in that sensor, the coil driver wasn't sending any voltage out. The voltages measured all matched. We did this test with offsets of 5,000 and then of 50,000, and we correctly saw a difference in a factor of 10 in the voltage.

UL	OFFSET in COILOUTF [cts]	Voltage [mV]
	5,000	-10.5
	50,000	-105
LL	OFFSET in COILOUTF [cts]	Voltage [mV]
	5,000	+10.4
	50,000	+102
UR	OFFSET in COILOUTF [cts]	Voltage [mV]
	5,000	-10.7
	50,000	-108
LR	OFFSET in COILOUTF [cts]	Voltage [mV]
	5,000	+10.5
	50,000	+105

Aux channel check with Coil driver to satamp chain
We also tried turning on all the L1 COILOUTF offsets at once (all offsets of 50,000) without the plug plugged into the other side of the breakout board. All channels react the same with their VOLTMONs reading in the 1000s and we were reading ~9 V on the mulitmeter, then once the cable is plugged back in, we see the FAST IMONs and RMS IMONs jump to their normal values, and the voltage on the multimeter dropped to the values in the table as the current was able to flow (ndscope4).

Swapping PD to AA inputs
We also tried swapping the PD to AA cables on the L1 coil driver (SUS_ETM_022) with the PD to AA cable on the R0 F1F2F3 coil driver (SUS_ETMX_014), and saw no difference in the LL signal.

Swapping satamps
We also tried swapping the ETMX L1 satamp with the ETMX M0/R0 LF/RT satamp. LL still reacted the same way as it had been reacting earlier. This rules out the satamp.

Fake osem signal
Fil had the idea of sending fake osem signals into the satamp to more confidently rule out the satamp/AA/ADC path. We sent a signal into each channel and LL saw the signal exactly the same as the other osems, so that rules out that path as the issue(ndscope5).

SUS

Images attached to this report

H1 AOS - POP power measurement on ISCT1

louis.dartez@ligo.org — Mon, 24 Aug 2026 18:05:47 -0700

Author: louis.dartez@ligo.org

Report ID: 91657

[Jenne, Keita, Louis] Following up on the POP path issues mentioned in 91647. Keita suggested measuring the power in the POP beam on ISCT1 to 1.) compare it against what we expect to have and 2.) to compare it with different spot positions on PR2. Today we did the initial measurement. We'll need to come back (hopefully tomorrow) to repeat after moving the PR2 spot position. We did the measurement in single bounce with ITMX with 60 W input power (which put 55.3 W at the PRM). Following Keita's suggestion, Jenne turned on POPX centering and noted a POPX NSUM value of 0.76. After each spot position change on PR2 we will remeasure the power in the POP beam just out of the periscope and note any fluctuations in the POPX NSUM (centered). Having both numbers should help us determine if we are clipping upstream or downstream of the dichroic splitter (M10). There is good reason to suspect that we are clipping on the periscope on ISCT1 (see 91647 and 91481). We grabbed one of the red Thorlabs power meters from the optics lab and placed it just upstream of the POP beam shutter. At first the power meter read about 71 uW steadily. After a few moments, the power meter readout started to fluctuate from about 69 uW to about 72 uW. We couldn't immediately tell what was causing the swinging. The AS Air camera was stable and not swinging. The REFL camera was saturated (most likely because we had the door open on ISCT1). Trending back I found that POPX NSUM and YAW started being very noisy at 1471643523. This lasted for about 30 minutes. I have not been able to find a source. I checked suspensions and QPDs from POPX back to IM4, + PR3, BS, and TMs and could not identify a culprit for the 'swinging'. There was a power glitch in the afternoon before we went out to ISCT1 but Ibrahim reported the glitch timestamp to be 1471640837, about an hour before the POPX issue. I put a screenshot showing POPX NSUM, YAW_OUT and a few other channels I checked during the same time (pop_isct1_shaking.png. There was some JAC-related ASC testing going on at around the same time but none of the trends I checked showed clear correlation to noise in POPX.

Images attached to this report

H1 ISC - Debug of ALS Y WFS auto centering

elenna.capote@ligo.org — Mon, 24 Aug 2026 17:28:22 -0700

Author: elenna.capote@ligo.org

Report ID: 91661

Keita, Elenna, Jenne

The ALS Y WFS were not working when engaged. I checked the WFS autocentering and we saw that the power on WFS B was very low, indicating clipping. The auto centering servo could not run because the threshhold was too low to engage, but even with sweeping the PZT steering mirror, we could not increase the WFS B sum great than 150 ct. Trending showed that both WFS A and B were close to 3000 ct in March when we last locked ALS on both arms.

We could make large moves in TMSY and ETMY to bring the power up on both WFS, but the autocentering would rail. Keita stated this indicated something was very wrong, and we could be clipped somewhere on the way to WFS B.

Keita and I drove down to EY, and opened the table. We confirmed that WFS A is labeled correctly by covering it with a card. We could see a strange clipping pattern in front of WFS B. We looked along the path and saw that a bundle of cables related to the HWS and the old analog camera placed there were hanging partly in the beam. Once we moved the cables out of the way, the power on WFS B return to 2800 ct, which is nominal. Now the autocentering of WFS B works.

We removed the analog camera from the table, and coiled the remaining cables on top of the cable rack above the table. We also unplugged the power cable for the camera.

Ok, we were confused about why WFS A was not working, but it turns out I accidentally turned off the integrators when we were troubleshooting the WFS earlier today (sorry).

If we request WFS on in the guardian, the WFS engagement causes a lockloss. However if we go to a No WFS slow controls state, and then engage the WFS by hand it does not cause a lockloss. However, the WFS loops are not yet converging.

Image 1 shows the beam clipping on the cables on the table.

Image 2 shows the beams unclipped.

Image 3 shows our cable solution.

Images attached to this report

H1 ISC - Comment to ETMX ALS issues maybe caused by issues with ETMX L1 LL Output

camilla.compton@ligo.org — Mon, 24 Aug 2026 16:59:55 -0700

Author: camilla.compton@ligo.org

Report ID: 91660

Attaching green locking this morning, when we locked green in March, and in O4, the L1 LL behavoiur is different now than before.

Images attached to this report

LHO General - OPS Day Shift Start

ibrahim.abouelfettouh@ligo.org — Mon, 24 Aug 2026 16:31:50 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 91659

TITLE: 08/24 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY:

IFO is in MANUAL_INITIAL_ALIGNMENT at 2W

Lot's of alignment work today, mostly on getting ALS working:

ALSY locking has some issues with WFs that are being troubleshot. Elenna and Keita are hazard at EY now confirming alignment is okay at ISCTY. This can lock but WFs turn it unstable.
ALSX locking issues from last week also have issues with the WFs. Oli and Fil went down to EX and found that the UIM ETMX is anomolously unresponsive compared to the others. It doesn't show the normal breathing and doesn't respond to actuation. This became one of the main investigations of the day which included Oli, Fil, Betsy, Camilla and Jenne. Trending shows that the OSEM and Oplev counts have not changed. More info in alog 91650 and alog 91655. This can lock but again, WFS turn it unstable.
ISCT1 alignment confirmation using 60W was done and seemed successful.
We had another power glitch where OPS (Ryan S and Oli) had to go to the end stations to power cycle HEPI while Jim was watching. This is happening more often and Richard has said he's thinking about a long term failsafe.

LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
16:32	VAC	Travis	LVEA	Y	HAM7 Check	16:47
16:33	FAC	Tyler + Guest	LVEA	Y Tour		16:47
16:51	FAC	Kim	MY	N	Technical cleaning	17:51
18:03	EE	Fil, Oli	EX	N	ETMX L1 Electronics	20:03
18:07	TCS	Camilla	CHETA Lab	N	Photos	18:13
20:38	ISC	Jenne, Louis, Keita	LVEA	Y	ISCT1 alignment (Jenne out and Keita in at 21:35 UTC)	22:15
20:38	AOS	Mitchell	LVEA	-	Dog clamps	21:39
21:09	OPS	Ryan S	EY	N	Reset WD	21:48
21:10	EE	Oli, Fil	EX	N	ETMX L1 Electronics and cycle WD	21:54
21:10	SUS	Betsy, Jim	CER	Y	Look at racks	21:38
22:30	TCS	Camilla, Jackie	Cheta Lab	N	Photos	22:59
22:59	ISC	Keita, Elenna	EY	Y	Checking beams on ISCTEY	00:59

H1 SEI - Comment to CRS Ellipse Fitting Changes

shoshana.apple@ligo.org — Mon, 24 Aug 2026 15:57:27 -0700

Author: shoshana.apple@ligo.org

Report ID: 91658

I ended up also looking at the most recent time the CRS was rung up (2026-08-19 05:00:00) for a 10 second window. I got a similar result (below) to for longer periods when the CRS is damped down, which implies that the difference in the HoQI2 Offset isn't due to either of those factors, and is infact either because it has drifted, or because the original offset wasn't great.

10s from 2026-08-19 05:00:00
HOQI 1:
OFFSET X0=-0.0730847 --> -0.07069 [-3.2% Change]
OFFSET Y0=-0.0595926 --> -0.05883 [-1.3%]
Axes a: 0.794142406 --> 0.76297 [-3.9%]
Axes b: 0.71738585 --> 0.68999 [-3.8%]
Rotation Ang: 146.645-->146.82° [0.12%]

HOQI 2:
OFFSET X0=-0.0606974 --> -0.05580 [8.1%]
OFFSET Y0=0.00274197 --> 0.00563 [105%] ????
Axes a: 0.6477522995 --> 0.61450 [-5.1%]
Axes b: 0.61753553917 -->0.58815 [-4.8%]
Rotation Ang: 162.256-->161.40°° [0.53%]

H1 SEI - CRS Ellipse Fitting Changes

shoshana.apple@ligo.org — Mon, 24 Aug 2026 14:57:14 -0700

Author: shoshana.apple@ligo.org

Report ID: 91652

I re-wrote the ellipse fitting code for the CRS (previously /opt/rtcds/userapps/release/isi/h1/scripts/write_ellipse_values3.py ---> /opt/rtcds/userapps/release/isi/h1/scripts/write_ellipse_values4.py)

While the script works well while the CRS is rung up (i.e. moving a lot), I was running into an error where the previous duration was set much too low (2 seconds), and the CRS wasn't moving enough to get enough data to construct a full ellipse, which would either result in an error or an incorrect fit.

I've made a new version (write_ellipse_values4.py) for when the CRS isn't rung up where you can pick the duration and it can look at data from a earlier time (i.e. ask to use 20 minutes of data starting 20 minutes ago).

I ran the ellipse fitting code for multiple times over multiple periods from over the weekend, while each time gave a slightly different result (listed below), most gave a change of <10% of values vs the current values, with the exception of the HoQI2 y0 Offset, which had a >10% change for all runs and had a max of an 146% change. This either indicates that the HoQI2 signal is drifting significantly, or the original HoQI2 offset used wasn't great.

1600s from 2026-08-24 10:00:00
HOQI 1:
OFFSET X0=-0.0730847 --> -0.07301 [-0.1022% Change]
OFFSET Y0=-0.0595926 --> -0.05879 [-1.35%]
Axes a: 0.794142406 --> 0.77781 [-2.1%]
Axes b: 0.71738585 --> 0.70098 [-2.3%]
Rotation Ang: 146.645-->147.03° [0.26%]

HOQI 2:
OFFSET X0=-0.0606974 --> -0.06256 [3.1%]
OFFSET Y0=0.00274197 --> 0.00589 [114%] ????
Axes a: 0.6477522995 --> 0.68223 [5.3%]
Axes b: 0.61753553917 -->0.65521 [6.1%]
Rotation Ang: 162.256-->161.22° [0.64%]
---------------------------------------------------
2026-08-23 10:00:00 3600s

HOQI 1:
OFFSET X0=-0.0730847 --> -0.07455 [2% Change]
OFFSET Y0=-0.0595926 --> -0.06007 [0.8%]
Axes a: 0.794142406 --> 0.78580 [-10.5%]
Axes b: 0.71738585 --> 0.71265 [-0.7%]
Rotation Ang: 146.645-->146.74° [0.06%]

HOQI 2:
OFFSET X0=-0.0606974 --> -0.06395 [5.4%]
OFFSET Y0=0.00274197 --> 0.00676 [146%] ????
Axes a: 0.6477522995 --> 0.69167 [6.7%]
Axes b: 0.61753553917 --> 0.66174 [7.1%]
Rotation Ang: 162.256-->160.98° [0.79%]
----------------------------------------------------
2026-08-23 11:00:00 1600s

HOQI 1:
OFFSET X0=-0.0730847 --> -0.07124 [2.5% Change]
OFFSET Y0=-0.0595926 --> -0.05432 [8.8%]
Axes a: 0.794142406 --> 0.75956 [-4.4%]
Axes b: 0.71738585 --> 0.68506 [-4.5%]
Rotation Ang: 146.645-->146.27° [0.26%]

HOQI 2:
OFFSET X0=-0.0606974 --> -0.06083 [0.22%]
OFFSET Y0=0.00274197 --> 0.00469 [71%] ????
Axes a: 0.6477522995 --> 0.67375 [4.0%]
Axes b: 0.61753553917 --> 0.64620 [4.4%]
Rotation Ang: 162.256-->160.73° [0.94%]
-----------------------------------------------------
2026-08-23 11:00:00 1000s

HOQI 1:
OFFSET X0=-0.0730847 --> -0.07251 [0.79% Change]
OFFSET Y0=-0.0595926 --> -0.05377 [9.8%]
Axes a: 0.794142406 --> 0.76077 [-4.2%]
Axes b: 0.71738585 --> 0.68627 [-4.3%]
Rotation Ang: 146.645-->145.57° [0.7%]

HOQI 2:
OFFSET X0=-0.0606974 --> -0.06151 [1.3%]
OFFSET Y0=0.00274197 --> 0.00520 [89.6%] ????
Axes a: 0.6477522995 --> 0.67432 [4.1%]

Rotation Ang: 162.256-->161.59° [-0.41%]

Images attached to this report

H1 TCS - TCS Chiller Water Level Top-Off and sock filter replacement

thomas.shaffer@ligo.org — Mon, 24 Aug 2026 14:02:04 -0700

Author: thomas.shaffer@ligo.org

Report ID: 91654

FAMIS81869

With our FAMIS tasks up and running again I was reminded to swap out the chiller sock filters. The old filters both were slightly discolored, but there were no large bits of debris or other worrying particulate. I also replaced the X chiller radiator screen cover as it had a few dead bugs in it and hair.

I did not add any water as it was at a good levels for both chillers. I've updated T2200289.

H1 PSL - PSL 10-Day Trends

ryan.short@ligo.org — Mon, 24 Aug 2026 13:49:28 -0700

Author: ryan.short@ligo.org

Report ID: 91653

FAMIS 63913

Jason's brief entrance into the enclosure last Tuesday is clearly seen on several trends, but no major events of note this week otherwise.

Images attached to this report

H1 SEI - Comment to Continue CRS commissioning and testing with different ISI configs

brian.lantz@ligo.org — Mon, 24 Aug 2026 12:21:47 -0700

Author: brian.lantz@ligo.org

Report ID: 91651

"3 again. ... We should test the new l2l."

No, we should abandon the Local 2 Local measurements. It is useful to see if sensors are alive and working, but not useful for precision calibration. The CPS and GS-13 are in different places, so they respond differently to RX and RY motion. When we drive 1 actuator, we impose lots of RX and RY motion. Trying to make the local GS-13 and local CPS match each other is a mistake, because it would be extrememly surprising if they were seeing the same signal. When the payload changes, the (RX or RY)/Z motion changes is a frequency dependent way, so the L2L measurements are likely to change.

The comb drive tries to fix this. The excitation is a mostly vertical signal, and then the code does a virtual repositioning of the CPSs to the GS-13 location. Seeing that the blue curves match so well is reassuring.

H1 ISC - ETMX ALS issues maybe caused by issues with ETMX L1 LL Output

camilla.compton@ligo.org — Mon, 24 Aug 2026 11:38:19 -0700

Author: camilla.compton@ligo.org

Report ID: 91650

Oli, Fil, Camilla, Jenne,

We followed on from Keita's Friday issue with ALS WFS 1.6Hz wobble 91647, found it was WFS DOF 1 PIT, increasing or decreasing gain, this did not help. This pushes on ETMX (as does tidal) so Oli in turn turned on offsets in ETMX TEST banks while we watched all the inputs. All M0 was fine. In L1, while pushing on LL nothing moved. See attached. Fil found it strange that the H1:SUS-ETMX_L1_VOLTMON_LL_OUT16 did behave as expected though.

The L1 LL readback didn't react when UL was moved. It did move 6urad when we turned the YAW slider off (our initial test) but the shape of the trend is different than the others, and it didn't move after that, attached.

Fil and Oli went to EX to investigate.

SUS

Images attached to this report

H1 SEI - Comment to Continue CRS commissioning and testing with different ISI configs

huyen.pham@ligo.org — Mon, 24 Aug 2026 09:10:52 -0700

Author: huyen.pham@ligo.org

Report ID: 91607

3 again. The symmetrization filters: The new comb drive filters are suprisingly very similar to the old comb drive ones, while the l2l drive filters old vs new filters are distinctly diferrent - see figure 1. We should test the new l2l.

4. Remeasure CRS resonance (tilt to tilt TF): I used the same ry_exc2.txt awggui template but to get the same drive amplitude, I have to up the gain to 7e3 instead of 2e3 as last time this was measured (alog 91179). After fitting, the result shows that the resonance moved very slightly, see figure 2. The delta (distance between CoM and Center of Rotation) moved from 11µm to 10µm, and the natural frequency moved from 22.22mHz to 22.11mHz. I updated new sensor inversion anyway in both theta filter bank and the 30mHz bandpass of the blend, see figure 3. I also did two excitations with low gain that might be good for SPI commissioning. The excitation time shows below (no CRS damping nor CRS in-loop for these).

Date	Time start	Duration	Gain	Note
08/17/2026 PDT	20:57	30min	8e3 - 1e4	ISI isolated. SPI QPDA pit and yaw under 0.3
08/18/2026 PDT	08:20	1hr	2e3	ISI damped. SPI QPDA pit and yaw under 0.3
08/18/2026 PDT	20:35	1.5hrs	8e3	ISI damped

5. Horizontal to tilt coupling above 1Hz: An excitation in X direction was done via ISO_X path, see figure 4, and the dtt is saved in /ligo/svncommon/SeiSVN/seismic/HAM-ISI/H1/HAM3/CRS/Templates/dtt/HAM3_CRS_X_to_RY_coupling_1-100Hz_20260818.xml. The coupling starts to subside as above 1.5Hz. This length drive also excited the torsional mode of the CRS around 8.7Hz.

Images attached to this report

LHO General - OPS Day Shift Start

ibrahim.abouelfettouh@ligo.org — Mon, 24 Aug 2026 07:46:37 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 91649

TITLE: 08/24 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
SEI_ENV state: EARTHQUAKE
Wind: 5mph Gusts, 3mph 3min avg
Primary useism: 0.14 μm/s
Secondary useism: 0.11 μm/s
QUICK SUMMARY:

IFO is IDLE

Continuing alignment work today.

H1 CDS - h1iopoaf0 timing error, 2nd ADC, Sun 19:04 23aug2026 PDT

david.barker@ligo.org — Mon, 24 Aug 2026 07:41:57 -0700

Author: david.barker@ligo.org

Report ID: 91648

EJ, Dave:

We got another "2nd ADC timing error" event last night on h1iopoaf0. The previous one was Wed 11aug2026 on h1iopiscex (alog 91508). Unlike the h1iscex one, h1iopoaf0's cpu did not spike, but it is running high anyway. No dmesg log was generated.

It is looking more likely this is software and not an issue with the second Adnaco backplane as postulated in the 11th Aug alog.

Images attached to this report

H1 ISC - Belated Friday 21/Aug/2026 commissioning report

keita.kawabe@ligo.org — Mon, 24 Aug 2026 00:01:53 -0700

Author: keita.kawabe@ligo.org

Report ID: 91647

1. ALSX is not healthy yet

Slow servo to ETMX (tidal) doesn't work yet. The feedback signal actually pushes the ETMX. I can see that the oplev moves by as large as 1urad or so when tidal into L1 is active but I don't know if that's the reason why ALSX loses lock as soon as slow is enabled. Ryan confirmed that the L2A gains/filters didn't seem to have changed recently.

I tried turning on green WFS (but not camera) without slow servo by going to ENABLE_WFS and turning off camera servo manually. That resulted in a slow 1.6Hz oscillation. I gave up after failing twice.

2. It seems that POP beam needs to be moved in +Y direction on HAM1/HAM2 septum

Not everything makes sense but it seems that POP beam needs to be steered in +Y direction on HAM1HAM2 septum (-X direction in ISCT1).

I looked at the single bounce beam from ITMX at 60W in ISCT1 and the beam seemed to be shifted too much in +X direction on ICST1 top periscope mirror compared with how I set the path up when ISCT1 was open. See POP_beam_too_much_to_the_left.jpg.

I quickly moved the POP beam in HAM1 using just PR3 angle as a quick and dirty method. I used POP_X_SUM as the power monitor for the single bounce beam in HAM1. I used PM1 to center POP_X. Without centering, when the beam is close to the center, a change in the beam position will result in a meaningful increase of power due to the center gap between the PD elements. If the beam is entirely in one quadrant this isn't an issue but it's difficult to know if that's the case when you're intentionally moving the beam.

I moved PR3 YAW from -236.7 to -245.7urad (PIT wasn't moved) and used PM1 to compensate. As the beam moved, at first the power didn't seem to change much if at all, but eventually it increased from 42 counts to 48 counts. This was pretty repeatable. I couldn't move PR3 further as PM1 railed. See POP_X_SUM_increase.png and POP_beam_after_PR3_move.jpg.

After moving PR3 I lost the beam on POP_A completely but that wasn't surprising. Even before moving PR3, by scanning PM1 I saw that the beam was not centered on POP_A when POP_X was centered. (The POP_X and POP_A see the same beam coming through the 334mm lens, but the distances from the lens to POP_X and POP_A are about 390mm and 310mm according to my eyeballing D1000313. That's large enough of a difference. If for example the beam position on PM1 changes by 5mm and you use PM1 to center the beam on POP_X, the beam position shifts by ~1mm on POP_A, that's already the radius of POP_A PD.)

After this excercise I moved PR3 and PM1 back to where they were before I started.

Not sure if we're ready to use pico in HAM3 yet as not everything seems to make sense. For example Masayuki and Sheila moved spot position on PR2 and saw no change in POP power.

3. Realigned COMM and DIFF

In the COMM path the beams were too low on the common BS and was heavily clipped. I fixed that and the COMM beat note changed from ~ -1.3 to 5.9 dBm. I changed the DIFF path too but it didn't change much.

See COMM_and_DIFF_touchup.png.

ISC

Images attached to this report

H1 General - OPS Friday EVE shift summary

ryan.crouch@ligo.org — Fri, 21 Aug 2026 17:57:08 -0700

Author: ryan.crouch@ligo.org

Report ID: 91646

TITLE: 08/22 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Keita investigated the beams out on ISCT1, he relocked green after he was finished, they still look good (~1.15 for ALS-Y, and ~0.75 for ALS-X). I'm leaving them unlocked.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
22:19	PEM	Robert	EX	N	Troubleshooting ground injection	00:10
22:21	ISC	Keita	LVEA	Y	Checking beams on ISCT1	00:49
23:24	PEM	Reinhardt	LVEA	Y	Checking on DAS fiber	23:51

H1 CDS - tconvert leapseconds file updated

david.barker@ligo.org — Fri, 21 Aug 2026 16:55:42 -0700

Author: david.barker@ligo.org

Report ID: 91645

Oli, Erik, Dave

Oli found that tconvert was complaining of an expired /ligo/data/tcleaps/tcleaps.txt file. The "valid through" line in this file is the UNIX time for 07aug2026, which is when we think this warning started.

We have extended the "valid through" time by 10 years, it will expire August 2036.

LHO General - Ops Day Shift Summary

ryan.short@ligo.org — Fri, 21 Aug 2026 16:32:40 -0700

Author: ryan.short@ligo.org

Report ID: 91644

TITLE: 08/21 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Quiet day for the most part with a Beckhoff reboot, more alignment work with ALS troubleshooting, various PEM activities, and a couple of tour groups. The JAC temperature servo still appears to be settling out slowly since the reboot, causing the JAC to unlock periodically (trend attached). The LVEA remains Laser HAZARD.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
17:29	CDS	Daniel	CR	-	Beckhoff computer restart	17:55
18:34	PEM	Robert, Reinhardt	LVEA	-	Shaker on output arm	23:23
21:46	PEM	Miranda, Shrey	MER	-	Set up seismometers	22:15
22:19	PEM	Robert	EX	-	Troubleshooting ground injection	Ongoing
22:21	ISC	Keita	LVEA	Y	Checking beams on ISCT1	Ongoing
23:24	PEM	Reinhardt	LVEA	-	Checking on DAS fiber	Ongoing

Images attached to this report

H1 CDS - Comment to New DAQSTAT

david.barker@ligo.org — Fri, 21 Aug 2026 15:10:01 -0700

Author: david.barker@ligo.org

Report ID: 91643

Claude has written a DAQSTAT User Guide, which I've posted to the DCC as T2000607

H1 CDS - h1syscssqzsdf restarted after getting stuck.

david.barker@ligo.org — Fri, 21 Aug 2026 14:06:03 -0700

Author: david.barker@ligo.org

Report ID: 91642

SQZ slow controls SDF became unresponsive late this morning. I tried a restart of this model on h1ecatmon0

> rtcds restart h1syscssqzsdf

but it did not read the monitor request file and ran with zeros in all the channel counts.

After verifying the monitor.req and safe.snap files existed and looked ok, I did a slow stop/start of this model with about 1 minute inbetween. This time it read the monitor file and is monitoring 1340 chans.

H1 CDS - Comment to Beckhoff PC restart (Ryan, Daniel, Keita)

ryan.short@ligo.org — Fri, 21 Aug 2026 13:46:26 -0700

Author: ryan.short@ligo.org

Report ID: 91641

Restored some ISC settings following Beckhoff reboot, SDFs attached.

Images attached to this report

H1 CDS - New DAQSTAT

david.barker@ligo.org — Fri, 21 Aug 2026 13:33:00 -0700

Author: david.barker@ligo.org

Report ID: 91640

I've completed the upgrade of DAQ stat. New features ported from the old system are:

- DC broadcast list check-sums must be identical

- DC FE network port bandwidth must match within a tolerance

- FWs disk usage is displayed, warnings issued to too large or too small

The MEDM was getting too tall to fit a 2k monitor, so the framewriter section was moved to the right.

Remaining task is to add the new channels to the DAQ next week.

Images attached to this report

H1 CDS - Beckhoff PC restart (Ryan, Daniel, Keita)

keita.kawabe@ligo.org — Fri, 21 Aug 2026 12:05:35 -0700

Author: keita.kawabe@ligo.org

Report ID: 91639

Daniel tried to rebooted Beckhoff PC remotely, but it didn't come back so he rebooted it in MSR.

After that things came back mostly, there were two major exceptions:

1. JAC WFS whitening/dewhitening mismatch.

WFS whitening was off for two stages we use but the anti-whitening was on. WFS was at first turned on by the guardian when we tried to lock JAC and it totally misaligned it. We had to manually locked JAC, noticed that the alignment was off, cleared WFS history both in WFS feedback filters as well as JM1 lock filters, fixed the whitening/dewhitening mismatch by pressing "ON" buttons for two whitening stages, and after that it started working OK.

2. JAC got cooler, temperature servo overheats at first, and we're only getting 15 minutes lock stretches for now.

It took about 20 minutes for the Beckhoff to come back because the first reboot attempt didn't work (1st attachment). Thermistor 1 temperature dropped by about 0.05 degC as the temperature servo wasn't doing anything (2nd attachment, it looks like a sudden change but it's not, it's just that the Beckhoff EPICS numbers were frozen before that). Temperature servo started heating it hard as soon as it came back, overshot and tried to reduce heating, but it's still heating harder than it used to. Because of that, JAC lock PZT voltage quickly goes to zero after relocking. We'll have to wait.

CDS, ISC

Images attached to this report

H1 ISC - Comment to ALSY WFS demod RF level monitor is broken but the fast channels are working fine but Beckhoff computer needs rebooting tomorrow (Mark, Fil, Daniel, Keita)

daniel.sigg@ligo.org — Fri, 21 Aug 2026 11:36:56 -0700

Author: daniel.sigg@ligo.org

Report ID: 91638

Main Beckhoff computer rebooted. Required a power cycle.

H1 PEM - Comment to Corner Station PEM Accelerometer mismatch identified and fixed

mirandarose.claypool@ligo.org — Fri, 21 Aug 2026 09:39:24 -0700

Author: mirandarose.claypool@ligo.org

Report ID: 91637

For detchar: Based on our (dave, robert, my) best guesses, this error starts on JAN 26th 2024 when the ENdevcos, as well as the signal conditioners for the accelerometers, were replaced (alog 75592). This is post end of O4a (Jan 16th 2024), so the data for O4a is okay, but the data for O4b/c is affected. This means that if there's an hveto round winner/trigger/pemcheck correlation/etc for one of the three channels on the right, it will instead be data from the detector on the left column. For clarity:

If the trigger says H1:PEM-CS_ACC_BEAMTUBE_SRTUBE_X_DQ, then the data is actually from the lvea floor accelerometer, H1:PEM-CS_ACC_LVEAFLOOR_HAM6_Z_DQ.
If the trigger says H1:PEM-CS_ACC_EBAY_FLOOR_Z_DQ, then the data is actually from the beamtube accelerometer, H1:PEM-CS_ACC_BEAMTUBE_SRTUBE_X_DQ.
if the trigger says H1:PEM-CS_ACC_LVEAFLOOR_HAM6_Z_DQ, then the data is actually from ebay accelerometer, H1:PEM-CS_ACC_EBAY_FLOOR_Z_DQ.

Here are some examples that I hope help clarify (as I was also confused):

When Dave and I tapped the ebay floor accelerometer with a pen, there was a spike on the ham6 floor accelerometer channel. So, H1:PEM-CS_ACC_LVEAFLOOR_HAM6_Z_DQ was incorrectly reading data from the ebay floor accelerometer and not the lvea floor accelerometer.
Likewise, when Robert unplugged the srtube accelerometer, the ebay floor z channel disappeared. So, the H1:PEM-CS_ACC_EBAY_FLOOR_Z_DQ channel was receiving information from the srtube accelerometer.
I've also attached spectra that shows a few days before and after the switch, Jan 25th and Jan 29th, 2024. You can see the channel names change for the different spectra while retaining the same shape.

CDS, DetChar, PEM

Images attached to this report

LHO General - Ops Day Shift Start

ryan.short@ligo.org — Fri, 21 Aug 2026 07:43:57 -0700

Author: ryan.short@ligo.org

Report ID: 91636

TITLE: 08/21 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 1mph Gusts, 0mph 3min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.10 μm/s
QUICK SUMMARY: More alignment work expected today including attempting to fix clipping in the POP path. Beckhoff restart also expected this morning; the computer looks to have lasted the night. The X arm is currently locked in green with good IR flashes.

LHO VE - Comment to HAM7 Pumpdown Started

gerardo.moreno@ligo.org — Fri, 21 Aug 2026 00:04:26 -0700

Author: gerardo.moreno@ligo.org

Report ID: 91635

(Travis, Gerardo)
Update.
HAM7 chamber pumpdown continues to progress, see attached plot for pumpdown trend.
AIP, the annulus system continues to pumpdown also, small can turbo attached at the annulus and a small cube aux-cart backing the can turbo, with a pressure of 7.8X10^-06 Torr reported by the aux-cart, we turned the ion pump on a few days ago, and the system has made some progress, see attached plot for progress.

Images attached to this report

LHO VE - Comment to HAM1 Vent Recovery Update

gerardo.moreno@ligo.org — Thu, 20 Aug 2026 23:44:32 -0700

Author: gerardo.moreno@ligo.org

Report ID: 91634

Travis removed the aux-cart, SS-500, decoupled cables. Flex hose was removed the previous day. The SS-500 cart then got moved and now is installed on HAM6 turbo.

LHO General - OPS Eve Shift Summary

ibrahim.abouelfettouh@ligo.org — Thu, 20 Aug 2026 18:03:17 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 91633

TITLE: 08/21 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

IFO is in IDLE at 2W

Ryan C informed me of the Beckhoff issue that will require an early morning computer restart (alog 91611). In the meantime, comissioners Elenna, Keita and Louis were working on alignment, specifically trying to solve a clipping issue related to PR2 in PRMI acquisition.

During this, Elenna and Louis were putting IFO in single bounce IR with green arms on X to guage the alignment at the PRC. Then, they were going to pico. They'll continue tomorrow. Details in alog 91632

LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
15:02	FAC	Kim	LVEA	Y	Tech clean	16:06
15:36	TCS	Camilla	CR	N	ITMY CO2 blasting	16:36
16:20	VAC	Travis	LVEA	Y	Check HAM7 pumpdown	16:29
16:24	PEM	Reinhardt	LVEA	Y	PEM checks	18:09
16:41	FAC	Kim	MidY	N	Tech clean	17:42
16:44	ISC	Betsy	Mech room	Y	Equipment Checks	17:12
16:50	SEI	Jim, Mitch	Mids	N	Equipment checks	17:43
16:58	VAC	Travis	LVEA	y	Turning off turbo pumps	17:31
17:23	ISC	Camilla, Elenna	LVEA	Y	ISCT1 table DIFF beatnote adjustment	17:42
17:42	FAC	Kim	H2 building	N	Tech clean	17:53
19:54	ALS	Keita	EndY	N	Troubleshoot ALS WFS issue	21:16
19:56	ALS	Keita	CER	Y	Grab cds laptop	19:56
20:08	EE	Marc, Fil	EndY	N	ALS wfs troubleshooting	21:15
20:58	PEM	Reinhardt	LVEA	Y	PEM work cont. (fibers)	21:40
21:17	VAC	Travis	LVEA	Y	Finish turning off turbo pumps	21:23
21:33	TCS	Camilla	Prep lab	N	CHETA checks	21:50
21:43	SAF	Richard	Mech room	N	Reboot access system network switch	21:53
21:48	PEM	Robert, Reinhardt	Output arm	N	Shaker injections to tests new fibers	21:59
21:53	PSL	Jason	MidY then X	N	Look for old PSL chiller	22:28
23:47	TCS	Camilla	Optics Lab	N	Parts storage	23:51

H1 ISC - setting up for pop clipping tests

louis.dartez@ligo.org — Thu, 20 Aug 2026 18:01:31 -0700

Author: louis.dartez@ligo.org

Report ID: 91632

[Elenna, Louis, + guidance from Sheila, Jenne, Keita, Camilla] To investigate the POP clipping in 91549 we settled on a plan to pico in HAM3 while watching the POP pds and the ALS COMM beatnote. To do this we locked the x-arm in green and misaligned the y-arm. To get IR in HAM1 and on ISCT1 we set up single bounce using ITMX at 10W. We first had to adjust PM1 to get it centered on POP-X. This was done while locked on MICH dark. It took a while but we eventually got close enough for the POP-X centering to work. Once it did we offloaded the new positions onto the sliders. We rastered PM1 (pit, yaw) to demonstrate that we are hitting the maximum possible power on LSC-POP at the current alignment. We are getting predominantly 2f oscillations in POP-X but 1f in LSC-POP in both PIT and YAW, indicating that the beam is not completely well-centered on the LSC POP diode with the current upstream input alignment. Once we had a reasonable beam on the POP pds and a reasonable COMM beatnote, we started pico's in the HAM3 POP path. We moved what felt like large distances in X without seeing any change in the POP pds or the COMM beatnote. We tried a bit in Y too but didn't go nearly as far. This was towards the end of the day so we reverted the pico positions (as much as we can trust them) and paused for the evening. We plan to continue pico'ing to better understand the clipping situation in the POP path.

Images attached to this report

H1 ISC - ALSY WFS demod RF level monitor is broken but the fast channels are working fine but Beckhoff computer needs rebooting tomorrow (Mark, Fil, Daniel, Keita)

keita.kawabe@ligo.org — Thu, 20 Aug 2026 17:39:34 -0700

Author: keita.kawabe@ligo.org

Report ID: 91611

Summary:

Good news is that ALSY WFSA demod is working as far as fast channels go.
Bad news is that something is broken about LO and RF level monitors.
Another bad news is that Daniel found that Beckhoff PC needs rebooting very soon. We asked him to do that tomorrow.

Somewhat longer story:

Yesterday LO power for two out of four channels for ALSY WFSA demod (H1:ALS-Y_WFS_A_DEMOD_LOMONCHANNEL_3 and H1:ALS-Y_WFS_A_DEMOD_LOMONCHANNEL_4) were found missing. Attached trend shows that these channels were lost on July/16 at around 7:16AM local time, shortly after the power came back from the power glitch.

Fil and Daniel went to the end station and swap the chassis but only one channel was fixed, H1:ALS-Y_WFS_A_DEMOD_LOMONCHANNEL_3 was still bad.

Today I injected RF signal to the RF in of WFSA channel 3 and confirmed that the demod signal correctly appeared in both in H1:ALS-Y_WFS_A_I3_INMON and H1:ALS-Y_WFS_A_Q3_INMON. (For comparison I also injected into ch1 and saw the same response.)

I decided to leave it alone until Tuesday, but Daniel found that Beckhoff computer is in dire need for reboot. He said it MIGHT last for the night, it might not, and when the PC crashes it will affect many things but not PSL, and the wave plate rotator will be affected but will not move on its own after a crash. Since Louis and Elenna were working on pico-ing, we decided to try our luck.

Before going home I changed the laser power back to 2W. At this point the PC still seems to be running.

ISC

Images attached to this report

H1 SEI - DAS Installation on Vacuum Chamber and LVEA Floor

reinhardt.rading@ligo.org — Thu, 20 Aug 2026 17:34:31 -0700

Author: reinhardt.rading@ligo.org

Report ID: 91630

On Tuesday, August 18, and over the following two days, I installed the DAS fiber on the vacuum chamber and along sections of the LVEA floor with the help and guidance of Robert. The DAS interrogator system is located at the H1 TCS Chiller and is connected to the LVEA through the mechanical cable tray. From there, the fiber is routed across the piping bridge and down beneath the vacuum chamber to the seismometer (SEI GND STS). At the seismometer location, we created a fiber loop to enable a direct comparison between the DAS and seismometer recordings. The main objective is to compare the coherence between the DAS and seismometer measurements and to investigate the extent to which the intrinsic noise of the DAS system limits its performance in recording seismic and vibration signals. From the seismometer, the fiber was routed back and attached to the vacuum chamber, with approximately five to six turns around the chamber. The fiber was then routed back to the seismometer, where an additional loop was created around the instrument. I also performed several tapping tests to georeference the DAS channels and identify the different sections of the fiber. Based on these tests, we were able to distinguish the individual fiber sections and associate them with their corresponding physical locations. Photos of the installation are attached.

Images attached to this report

H1 CDS - h1daqscript0 powered down, its load-mon-epics temporarily served by edc_green_ioc

david.barker@ligo.org — Thu, 20 Aug 2026 17:17:27 -0700

Author: david.barker@ligo.org

Report ID: 91631

Jonathan, Dave:

daqstat was the last service to move off of h1daqscript0 (others were Dolphin network manager and daq_run_number_server). We powered this machine down at 16:30 today. I have temporarily greened the EDC by adding h1daqscript0's epics_load_mon channels to edc_green_ioc.

H1 CDS - DAQSTAT extended to match 3 frame writers

david.barker@ligo.org — Thu, 20 Aug 2026 17:01:54 -0700

Author: david.barker@ligo.org

Report ID: 91628

The LHO DAQ has three frame-writers. Two (FW0 and FW1) write to LDAS and have large disk arrays, the third (FW2) runs with a local disk and is used as a "tie breaker" if the two primary machines disagree with each other.

There are now 5 permutations of agreement between the 3 frame-writers:

All agree (0=1=2)

All disagree (0!=1!=2)

One disagrees with the other two ((0=1)!=2) ((0=2)!=1) and ((1=2)!=0)

Instead of a simple red/green LED indicator on the MEDM, we now have borders around each monitor which are red/green depending upon the agreement.

Images attached to this report

H1 General - OPS Thursday Day shift summary

ryan.crouch@ligo.org — Thu, 20 Aug 2026 16:30:36 -0700

Author: ryan.crouch@ligo.org

Report ID: 91623

TITLE: 08/20 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY: Multiple optics lab dust alarms throughout the day, corner alignment, we did not get to PRMI or DRMI as there was a ALS slow controls issue unlocking XARM. The main Beckhoff computer seems to be having connections issues, a restart is required to fix this, and it will be done tomorrow.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
15:02	FAC	Kim	LVEA	Y	Tech clean	16:06
15:36	TCS	Camilla	CR	N	ITMY CO2 blasting	16:36
16:20	VAC	Travis	LVEA	Y	Check HAM7 pumpdown	16:29
16:24	PEM	Reinhardt	LVEA	Y	PEM checks	18:09
16:41	FAC	Kim	MidY	N	Tech clean	17:42
16:44	ISC	Betsy	Mech room	Y	Equipment Checks	17:12
16:50	SEI	Jim, Mitch	Mids	N	Equipment checks	17:43
16:58	VAC	Travis	LVEA	y	Turning off turbo pumps	17:31
17:23	ISC	Camilla, Elenna	LVEA	Y	ISCT1 table DIFF beatnote adjustment	17:42
17:42	FAC	Kim	H2 building	N	Tech clean	17:53
19:54	ALS	Keita	EndY	N	Troubleshoot ALS WFS issue	21:16
19:56	ALS	Keita	CER	Y	Grab cds laptop	19:56
20:08	EE	Marc, Fil	EndY	N	ALS wfs troubleshooting	21:15
20:58	PEM	Reinhardt	LVEA	Y	PEM work cont. (fibers)	21:40
21:17	VAC	Travis	LVEA	Y	Finish turning off turbo pumps	21:23
21:33	TCS	Camilla	Prep lab	N	CHETA checks	21:50
21:43	SAF	Richard	Mech room	N	Reboot access system network switch	21:53
21:48	PEM	Robert, Reinhardt	Output arm	N	Shaker injections to tests new fibers	21:59
21:53	PSL	Jason	MidY then X	N	Look for old PSL chiller	22:28

Started by aligning and locking the green arms, then Camilla and Elenna went out to improve the diff beatnote (-18 -> -11)
18:11 -19:22 UTC EQ mode from a 6.7 from Peru
19:37 UTC Automated phone call from Hanford regarding take cover drill today
- Another call a few minutes later to terminate it
~20:00UTC manual initial alignment started
I was able to increase the power on ALSX by ~10/15%, up to ~0.75 while rechecking alignment after the earthquake

H1 ISC - Comment to Both arms locked on green!!

jenne.driggers@ligo.org — Thu, 20 Aug 2026 16:14:24 -0700

Author: jenne.driggers@ligo.org

Report ID: 91629

Notes on the baffle PD script issues in https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=91627

H1 ISC - Green baffle script challenges

jenne.driggers@ligo.org — Thu, 20 Aug 2026 16:13:55 -0700

Author: jenne.driggers@ligo.org

Report ID: 91627

Jenne, Keita, Louis, Elenna

As noted in alog 91610, we struggled to use the green baffle scripts for setting the pointing of the ITMs. We ended up doing the process of the baffle script by hand to set both ITMX and ITMY. We did so with the IMC unlocked.

I think the issue (or, at least a significant piece of it) is that the script is likely looking for the _NORMALIZED_ channel to have a peak at 1, but actually it's getting up to 10 or 12. Also, at least with our (mis)alignment yesterday, the main beam was getting into the baffle PDs enough to send their values above 1, even without any actual green beam being on the PDs. So, the script was "optimizing" the "green pointing" by looking at IR beam that was completely independent of any ITM pointing.

As I write all of this, I realize that I did not personally run the ISC_LOCK DOWN and SDF_REVERT states, so did not triple check that all the settings (eg PD gains) were set correctly. We should check that before making modifications to the script.

Fix #1: We set the IMC to OFFLINE, so that we wouldn't get any IMC flashes. This removed the IR beam from the equation, and the baseline level on the ETM baffle PDs went down to (or below) 0, rather than always being above 1.

Issue #2: Even with the IMC offline, the script would think things were close enough when the baffle PDs read a value above 1, even though that's actually on the edge of the PDs (whos peak values were closer to 10). To solve this, we just did the optimization by hand (put the sliders to roughly the right place, engage the M0_TEST offsets with the appropriate values, then adjust the sliders to find the peak of the PDs). We then noted the slider values, then put in the opposite TEST offsets for the other PD, and then re-adjusted the sliders to find the best place on the second PD. There are a few options for fixing this for use with the script. We can take the time to check that the gains are set correctly, such that the normalized value really should be going to 1. Or, we can ask the script to look at the rough peak heights, and then use that as the peak value to be looking for before considering it optimized. This second option is certainly less reliable than the first option of just fixing the normalizations.

Issue #3: For some reason that I don't understand, the values for the M0_TEST offsets, when applied to a well-aligned ITM, don't put you onto the ETM baffle PDs. You still have to move the sliders. I think this is equivalent to saying that when we applied those M0_TEST offsets and then optimized for the two baffles, we expect that the resultant slider values should be similar but they were not. We averaged our resultant slider values, and used those for the ITM positions. Someone should work to understand why these offsets aren't the correct values - has something changed? Or maybe there was a setting somewhere mis-set?

Issue #4: I don't think that the baffle PD scripts have a catch point for ctrl-c and a graceful exit. While we were running the script one of the times, we had a power glitch and tripped SEI and SUS at both end stations. I ctrl-c'd, but that did not stop the excitations. Louis "took over" the EXC slots using awggui, and that successfully stopped the excitations. We could have also killed the excitations. Either way, it would be nice if the script was graceful about it (turn off excitations, put in the misalign offsets that gets done at the end of the script, set sliders back to original values).

Issue #5: A few times the script noted while it was doing things that it failed to find one of the baffle PDs. That happens, not a big deal, and great that the script says so. But, if that happens, it would be nice if the "the script has finished" message adds information about whether or not it successfully found both baffle PDs.

H1 AOS - Comment to Locking green arms

ryan.crouch@ligo.org — Thu, 20 Aug 2026 15:07:47 -0700

Author: ryan.crouch@ligo.org

Report ID: 91622

I compared some power sensors like what RyanS did in alog91528 from our PRMI lock yesterday (08/19/26, GPS 1471225645) to a good lock at the end of 04 where we offloaded PRMI, then locked to NLN (11/16/25 GPS 1447346796).

	POP_A_LF	POPAIR_B_LF	REFLAIR_A_LF	POPAIR_B_RF18_I	POP_X_DC_NSUM	POP_A_NSUM	POP_B_NSUM	Refl_A_LF	Refl_B_LF	REFL_A_NSUM	REFL_B_NSUM
PRMI Nov 16th 2025	87	17.5	2.53	90	0.087 seems low just like the lock on Nov26th that RyanS checked	83	76	2.53	5.60	3890	3365
PRMI 08/13/26	30	6	2.57	30	160	8	5	2.55	5.60	3880	3350
PRMI yesterday 08/19/26	30.5	5.5	3.70	30	105	8	6.5	2.58	5.50	3925	3350

LHO General - UTC/PDT Local Time display problem

nyath.maxwell@ligo.org — Thu, 20 Aug 2026 13:42:07 -0700

Author: nyath.maxwell@ligo.org

Report ID: 91625

Testing UTC Function of Alog. Working to correct reflection of UTC to PDT/PST time zone.

H1 IOO - Comment to JAC WFS calibration, part 2: RF

nyath.maxwell@ligo.org — Thu, 20 Aug 2026 13:40:34 -0700

Author: nyath.maxwell@ligo.org

Report ID: 91624

H1 IOO - JAC WFS calibration, part 2: RF

masayuki.nakano@ligo.org — Thu, 20 Aug 2026 12:18:01 -0700

Author: masayuki.nakano@ligo.org

Report ID: 91621

Summary

I calibrated the JAC WFS A/B RF signals into the complex misalignment amplitude at the JAC waist, using four angular calibration lines at 62 W (measurement of Aug 14). The sensing matrix agrees with the one measured on Aug 12 and with the layout. Converting the two WFS signals into the real and imaginary parts of the misalignment (δ^r = lateral shift at the waist, δⁱ = tilt), the displacement part dominates by a factor of 4–5, which is consistent with the dominant jitter source being the PSL which is far (~90 deg of Gouy phase) from the JAC waist.

One question remains: the locked WFS DC does not sense on the plane 90 deg from the RF where it should; the unlocked DC does. Second-order modes are the prime suspect and analysis ongoing.

1. Measurement

With the cavity locked at 62 W we injected four angular calibration lines and recorded WFS A and B (RF I/Q of all segments, and the DC segments). The raw spectra are in wfs_spectra_0814.png. Three records were taken: all lines on ("LAline"), length lines only ("Lline"), and no lines ("noline"), plus a dark record for the sensor floor. The line list is as follows:

line	frequency	injected at
JM1 PIT	9.7 Hz	SUS-JM1 M1
JM1 YAW	11.3 Hz	SUS-JM1 M1
PZT PIT	13.1 Hz	IO PZT tip/tilt
PZT YAW	14.9 Hz	IO PZT tip/tilt
length	30 Hz	cavity length
length dither	2600 Hz	cavity length

The length lines are not for this post: they provide the demodulation reference for the double-demodulation signal, to be reported separately.

2. Sensing matrix in the actuator basis

From the heights of the four lines in each sensor we built the two 2x2 sensing matrix (actuator basis). The sensing-matrix vector figure is wfs_sensing_vectors_0814.png; it also carries the same measurement taken on Aug 12 and the layout-model prediction. The two measurement days agree very well. The model deviates by a few degrees per head (up to ~10 deg, table below), which we do not worry about, since WFS placement uncertainties and the actuators' own Gouy-phase uncertainties are of this order.

3. Sensor Gouy phases and the delta plane

The delta plane is the complex amplitude of the TEM10/01 content referenced at the JAC waist (accumulated Gouy phase = 0 there): the real axis is the waist lateral shift, the imaginary axis the tilt. An actuator kicking by an angle at accumulated Gouy phase η_a drives this amplitude with phase i·e^iηa; a sensor reads the projection of the amplitude onto its own axis.

Actuator parameters taken from the layout model (accumulated Gouy referenced to the JAC waist):

actuator	η_acc [deg]	w at actuator [mm]	k·w [per rad]
PZT (PIT/YAW)	-80.0	2.99	1.76e4
JM1 (PIT/YAW)	-32.2	0.65	3.82e3

Solving each head's sensing axis from its response to the two actuators of its plane:

sensor	η measured [deg]	η model [deg]	diff [deg]
A PIT	122.0	120.2	+1.9
B PIT	192.5	182.4	+10.1
A YAW	116.6	121.9	-5.3
B YAW	181.5	185.7	-4.2

The actuator vectors and sensor axes on the delta plane are drawn in wfs_delta_plane_0814.png.

4. Calibrated input jitter

With these calibration I got the main plot(wfs_delta_spectra_0814.png.) The two WFS signals inverted into the calibrated complex misalignment at the JAC waist, δ^r (lateral shift) and δⁱ (tilt).

δ^r dominates δⁱ by 4–5x. This makes sense: the dominant jitter source is the PSL, in air and far away (about 90 deg of Gouy phase), so its angular jitter, entering as i·e^iη, lands on the real (displacement) quadrature.
The structures above 100 Hz are coherent with the PSL periscope accelerometers, so they are caused by the PSL periscope.
The broad bump below 10 Hz is most likely caused by air convection inside the PSL enclosure.
The WFS picks up only about 5% of any post-JAC jitter (to be reported separately), so what is shown here is essentially the input jitter.

5. the locked DC

Calibrating the WFS DC the same way should give a sensing plane rotated 90 deg from the RF: the RF reads the tilt-like quadrature at its axis, the DC reads the beam position. But actually, tt does not. In wfs_sensor_gouy_states_0814.png the cyan/orange lines (locked-DC sensing axes) should lie on the blue/red dash-dotted lines (the RF axes rotated by 90 deg), but they point 30–70 deg away. The same solve on an unlocked, clean beam lands within about 10 deg of the expectation, so the sensors themselves are fine: something in the locked field is doing it, and the second-order (mode-mismatch) content is strongly suspected.

The analysis of this signal is in progress and will be posted shortly. Stay tuned.

IOO

Images attached to this report

H1 SUS - JMs OPTICALIGN slider gains calibrated into urad (+new slider values)

oli.patane@ligo.org — Thu, 20 Aug 2026 10:39:21 -0700

Author: oli.patane@ligo.org

Report ID: 91584

Calibration into urad has been done for JM1 and JM3's OPTICALIGN slider gains. The JM1 P and Y gain values match well with the values Masayuki found using a different method (91487), which is a nice double check.
The values to be put in {JM1,JM3}_OPTICALIGN_{P,Y}_GAIN and the necessary changes to the OFFSET values to keep the (current) OPTICALIGN OUTPUT the same are below, and were installed as of 2026/08/20 17:08-17:10UTC. Checking H1:SUS-{JM1,JM3}_M1_DAMP_{P,Y}_IN1 shows that pointing stayed the same before vs after this transition.
NOTE: This means that comparing slider values before vs after this calibration time will not make sense. Instead, you can look at the OPTICALIGN OUT16 values or the pointing using DAMP_IN1 channels since those will stay consistant.

	`JM1`			`JM3`
	`Calibration Gain [cts/urad]`	`OUTPUT (2026/08/19)`	`New OFFSET`	`Calibration Gain [cts/urad]`	`OUTPUT (2026/08/19)`	`New OFFSET`
`P`	`1.1771`	`-622.5`	`-528.8420695`	`1.1217`	`83.9`	`74.79718285`
`Y`	`1.0207`	`-1421`	`-1392.181836`	`1.1428`	`301.6`	`263.9131957`

Finding Calibration Gains
I used the method Jeff used in 77211 to get the counts -> urad calibration. So now when you move the OPTICALIGN slider by 1 in {Pitch,Yaw}, you actually get 1 urad in movement in {Pitch,Yaw}.

For each suspension, I put a series of OPTICALIGN offsets into Pitch and then into Yaw (only doing one dof at a time). At each offset, I wrote down the resulting values for DAMP_P_IN1 and DAMP_Y_IN1. Using these values I was able to fit a line for P2P, Y2Y, P2Y, and Y2P. I then inverted the slopes to get the calibration values in counts/urad.
On each plot I show the data points with the offsets removed (removed the 'b' from y=mx+b) for ease of slope comparison, and then also plotted the best fit line.

Both suspensions seem to have similar P2P and Y2Y as each other, but the cross-coupling is different. JM1 is a lot more cross-coupled with both P2Y and Y2P than JM3.

Finding New OFFSETs
OFFSET x GAIN = OUTPUT, and we want the OUTPUT to be the same as before, so we can just plug in our new GAINs and the OUTPUT that we want (aka the previous OUTPUT) and solve for OFFSET = OUTPUT / GAIN.

IOO, ISC

Images attached to this report

H1 AOS - Locking green arms

elenna.capote@ligo.org — Thu, 20 Aug 2026 10:00:44 -0700

Author: elenna.capote@ligo.org

Report ID: 91618

[Ryan C, Elenna, Matilda, Camilla, Louis]

We have locked each arm on green. Looks like the X arm build up on ALS TRX is about 0.6, and Y is about 1.2. The COMM beatnote is -3 dBm, and the DIFF beatnote is -20 dBm.

Going to LOCK SLOW GWFS ETM TMS on Y arm does not engage the WFS, but works, which means the slow controls do work on y arm. I guess the WFS are disengaged for now.

However, it appears the X arm slow controls are still not working. Going to no slow with green wfs on X arm requires going through a state that does engage the slow controls, so we're still sitting in "locking" on X arm.

Camilla and I are about to head to the table to touch up the DIFF beatnote.

We figured out how to engage the X arm WFS by hand and they are improving the buildup.

****

We (Camilla, Louis, Elenna) have aligned the DIFF beatnote to -11 dBm. The biggest move was ensuring the beam made it to the DIFF PD- Camilla found both edges of the PD using the steering mirror and centered the beam on the PD.

H1 CDS - alog times are erroneously being reported as UTC (since Tuesday)

david.barker@ligo.org — Thu, 20 Aug 2026 09:51:00 -0700

Author: david.barker@ligo.org

Report ID: 91619

This post made at 09:50 PDT.

Jonathan is working on the issue.

H1 TCS - CO2Y Alignment tuned to center on ITMY

camilla.compton@ligo.org — Thu, 20 Aug 2026 09:17:42 -0700

Author: camilla.compton@ligo.org

Report ID: 91616

Followed instructions in 68391 with 2 minute 2W CO2 blasts. Last done in 80834. Starting location with pico H1:SYS-MOTION_C_PICO_G_CURRENT_X,Y_POSITION at (0,0) starting hws plot attached. Aim to center on ITMY, center marked by origin cross using RH in 91567 went to that O4 SR3 alignment for this test. Endign picos are at (2000,0), ending hws plot attached.

Reverted SR3 to new location.

Once we know location of IFO beam, we should touch this up again.

Images attached to this report

H1 CDS - New DAQSTAT installed

david.barker@ligo.org — Thu, 20 Aug 2026 08:20:46 -0700

Author: david.barker@ligo.org

Report ID: 91615

Jonathan, Dave:

A new DAQSTAT system has been installed on H1 production. Following the recent DAQ upgrades it was found to be easier to rewrite the code rather than patch the original. The code has been made more portable for possible install at other locations.

Details:

code generated by Claude AI (Opus 4)

IOC runs in a deb13 container on the service-host cluster

Code generates MEDM and DAQ-INI files in the directory /opt/rtcds/services/daqstat_ioc/

Code is configured by the DAQSTAT.yaml file in the cds/h1/scripts directory

Code preserves state between restarts using a JSON file in the services directory

Images attached to this report

H1 General - OPS Thursday Day shift summary

ryan.crouch@ligo.org — Thu, 20 Aug 2026 07:37:09 -0700

Author: ryan.crouch@ligo.org

Report ID: 91614

TITLE: 08/20 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 4mph Gusts, 2mph 3min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.08 μm/s
QUICK SUMMARY:

More alignment work to be done today, DRMI locking
Dust, wind, and temperatures look good