[Nathan Holland, Jenne Driggers]

TL;DR

DC to 30 mHz BLRMS have been working as of 2022 - see LIGO-T2200025. These can be added to the BLRMS monitoring screen, and hopefully will be useful. They may need appropriate calibration. See attachment 1 for an example.

More Information

Historically the DC to 30mHz BLRMS did not work - they would diverge to +/- infinity after some time. This was corrected as of 2022, see LIGO-T2200025, by changing the C code in the RTCDS. This RTCDS change was approved in ECR LIGO-E2200027 and has been active for some time. One example of the relevant channels is H1:PEM-CS_SEIS_LVEA_VERTEX_X_BLRMS_0MHZ30, e.g. for the DC to 30 mHz seismic BLRMS at the LVEA along the x direction. Attachment 1 shows a 5 minute trace of the second trends for this channel.

Possibly this has been discussed in the past at the Friday SEI meetings, and no use yet, has been found for this BLRMS band. It may be interesting to properly calibrate these channels, place them on the monitoring screens, and then see if they are of use.

Sheila, Begum, Ryosuke, Camilla

Sheila checked that FC1 is now working as expected but was not in May 90462.

Started the morning by setting FC1 to the FC REFL iris ZM1,2,3 sliders set to 90183  (when Sheila had the beam on SQZT7), we then set irises after ZM1 and ZM3. Doing this clipped the return beam on B:L1 aperture, this is expected as we could not get the return beam through the OPO when FC was aligned in Feb.  Later we realized that this doesn't make scene, so set ZM1,2,3 sliders set to when we had good FC flashes in  89694 and then FC1 was moved to get the beam centered on the  FC REFL iris, again this clipped the return beam on B:L1 aperture but the beam was considerably higher at the ZM3 iris than when we originally set it. Around or a little higher than 6.25". Tomorrow we will fully think this though and compare to O4 times. 

We locked the OPO SUS iteratively looking at the beams off the OPO. It was finally lock with the FC REFL beam getting to the second iris but not centered and when we changed the alignment to the IR SQZT7 alignment, the beam made it through both irises when closed. 

Sheila, Begum, Ryosuke then took beam profiles of the beam after ZM1 and ZM2 with the borrowed Phasics camera.

Procedure checklist for both stations completed.  No issues were identified at this time.

MY: Scroll pump hours: 243
       Turbo pump hours: 105
       Crash bearings: 100%

EY: Scroll pump hours: 1304
       Turbo pump hours: 916
       Crash bearings: 100%

Closing WP 13279 and FAMIS 79948 and 79949

WP 13292
BSC2 Flange Layout - D1003079

Part of the BBS upgrade required moving the SUS BS field electronics from the SUS-R6 rack to the SUS-R2 rack. A new set of field cables were pulled from SUS-R2 to BSC2 flange E3 per D1003079. The old cables at the flange were disconnected and labeled as spares to avoid confusion. Access to the flange is limited as we now have the platform and dial indicators that limit access to the flange. The dial indicators were bumped. SEI team was notified.

TITLE: 06/03 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: HAM2 and HAM7 laser hazard work continued, the ITMY baffles install was finished, and the SPI electronics are being staged into the LVEA. The cartridge is planned to be flown back into chamber tomorrow.
LOG:         

• 15:05 UTC Light pipe open
• 18:24 UTC SUS OPO WD trip
• 23:09, 23:13 UTC ITMX SUS then SEI WD tripped

Before locking down the ITM suspensions as part of the new baffle installations, we measured the positions of each test mass and compensation plate (CP) from the outer bevel to the inner cage:

ITMY

Compensation Plate -

• Left: 9mm
• Bottom: 24mm
• Right: 8mm

Test Mass -

• Left: 14mm
• Bottom: 22.5mm
• Right: 16mm

ITMX

Compensation Plate -

• Left: 8.5mm
• Bottom: 20.5mm
• Right: 8mm

Test Mass -

• Left: 13mm
• Bottom: 20mm
• Right: 16mm

See attached photots for Anamaria's sketches of nominal positions and how they relate to the baffles.

Jennie W

Summary: JAC WFS A and B readout has been phased.

I used Sheila's tremplate for the IMC WFS phasing (see Daniel's alog #89457 here when the IMC WFS was rephased in March) to make one for JAC WFS phasing. Since the length control is all done through CDS and does not use a common mode board the actuation channel to use is H1:JAC-L_SERVO_EXC.

The template is saved in userapps/h1/ioo/templates/dtt/JAC_wfs_phase.xml

New values were saved in the h1ascimc safe.snap.

Here is a photo of the WFS 'Settings' screens with the value to change highlighted in red and the Q and I error points highlighted in green. When running the template a line is injected into the JAC lenght control loop at 8 Hz. To phase the readout of the WFS segments, change the red-highlighted phases to minimise the line you inject in the Q error point channels, H1:JAC-WFS_{A,B}_{Q1,Q2,Q3,Q4)_ERR_DQ

Last Friday, HAM7 was vented and the mega cleanroom was on, but chamber doors were on, FC1 sliders were at 100 urad P, -162 urad Yaw, and the M3 witness sensors were -90 urad pitch, -15 urad.  Since then, there was a power outage, the chamber doors are off and the purge air is on, and tha DAC has been changed as it was not working 90454.  Now, with the same slider settings (100 urad P, -162 yaw), M3 withness sensors are at 24 urad pitch, -204 urad yaw.  

In 89751, Oli noted that turning on the purge air caused a shift of -29urad in the bottom mass osems.  If purge air were the only difference between now and Friday, we would expect M3 witness osems to say -120 urad, if the purge air is similar to what it was in December.  So, it seems like the electronics change has changed the realtionship between the slider value and the witness sensor.  

On May 7th, we moved the pitch alignment slider by 140 urad, and the M3 witness only saw a move of 10 urad.  Today, when we move the slider by 262 urad, the M3 witness osems see a shift of 317urad, so the suspension is actuating now, but seems not to have been in May.  

As part of WP 13284, the unused 8" gate valve on the X-beam manifold section was removed and the port was blanked off.  We will need to remember to leak check this flange during pumpdown.

WP13772 TW0 Offload

Dave:

I have finally completed the TW0 offload which I started way back at 08:54 Saturday 30th May. It was interrupted soon after at 09:30 Saturday with the first of two power outages. It was restated 07:00 Monday 1st June and completed the file copy at 22:17 Monday night. 

NDS0 was restarted Tuesday morning to serve from the archive area, but sush7 and other issues delayed the file deletion from TW0 till Wednesday.

This morning I deleted the old files from TW0 between 07:40 - 10:05. SSD-RAID usage on TW0 went from 94% to 3%, ready for the next 6 months of trends.

Addressed TCS Chillers (Wed [Jun3] 713-726am local time) & CLOSED FAMIS #64381.   It's been a while since this has been checked due to issues with FAMIS for LHO.

For measurements below, measuring from "top" of the red floaty ball.

• TCSx Chiller:  Had level of 28.5 cm.  Added 270mL for 30.6cm.
• TCSy Chiller:  Had level of 9.0 cm.  Added 475mL for 10.5cm.  
• There was no water in the small cup under the slow leak.

TITLE: 06/03 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: MAINTENANCE
    Wind: 5mph Gusts, 2mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.12 μm/s 
QUICK SUMMARY:

• HAM2 work continues
• HAM3, cabling, SPI install?
• ITM cage baffling continues

J. Kissel, S. Koehlenbeck, J. Wright, P. Opperman

After the most of the day Monday (2026-06-01) ruling out of the prime suspect (the picomotors causing alignment drift; see LHO:90438), I left discouraged that we had ruled our everything that could be spatially wrong with the MEAS beam going into the MEAS IFO (power, alignment, mode-shape, and polarization). However, Sina and special-guest consultant Patrick spent time reviewing everything that we ruled out and/or what it could be -- and Sina left the lab nudging the NPRO seed laser's crystal temperature from 24.6 [deg C] to 25.2 [deg C].

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Executive Summary: Nudging the NPRO seed laser by 0.6 [deg C] (we believe) changed the resonant mode in the laser, stabilizing its output frequency. (We believe) the laser was in-some-way frequency drifting and/or mode hoping (a thing that would also be driven by the clean room environment in the ways we suspected were impacting the transceiver), and the path length differences between the REF and MEAS IFOs were discrepant enough (per the design layout) that the efficiency impact was much larger on the MEAS IFO. Having adjusted the laser crystal temperature, both IFOs are stable for hours and if/when small drift is seen its common to both IFOs as the gods intended. We can't claim we 100% understand it, or believe our own story, but it worked!

Finally happy with both the MEAS and REF IFOs, we mounted the transceiver vertically and confirmed its function in that orientation.

We're a go for install, and have started to dissect the production equipment from the optics lab.
%%%%%%%%%%%%%%%

Some victory photos attached.

Other things that happened:
    - Prior to laser temp adjustment -- with MEAS IFO path on fully manually driven mounts -- we foiled (as protection) then C3 covered (as isolation) the transceiver. We still saw drift. That put the nail in the coffin that it wasn't transceiver itself that was sensitive to the environment.
    - We re-installed all picomotor-driven IXM100 mounts to support M_M1, M_B4, and M_M2.
    - Prior to install, we were able to (rather barbarically) back off stopper nuts of the pitch picomotors for the M_B4 and M_M2, so there is no longer any question whether the stopper nut is driving moving plate. All pitch and yaw actuators push the moving plate kinematically via the intended ball-bearing-to-carbide-plate design.
    - Re-installed M_M4 M_M5 periscope mirror mounts, including their adapters and D1800200 Type 07 beam-dumps. The dumps were parked in a position that still allowed transmission of the MEAS beam (as confirmed with no change in the -- now stable! -- MEAS IFO efficiency).
    - Nudged IFO MEAS A and IFO REF A PDs because the beam spot on the diodes was a bit OFF.
    - Reviewed and confirmed all PD reflected beams were on their respective dump, except for the known issue with the FBR_PWRIN_REF PD that reflects 0.2 [mW] of power up above the breadboard.
    - Built up a temporary vertical mounting system with 1 [inch] posts and small cylindrical laser holding mounts with mini bread-board feet.
    - Re-installed the handles on ISIK.
    - Unbolted, and was easily able to single-person lift the entire assembly and mount it.
    - Both IFO efficiencies were actually not-that-bad after installing. Wow!
    - A quick alignment tune-up from Sina recovered all the IFO efficiency we had while mounted horizontally. 
    - Both IFOs were stable and happy for the entire series of victory photos we took; about 1 hr.

Camilla, Betsy, TJ, Fil, Ryan C, Richard, Erik, Dave

We had a very strange problem with the first 20bit-DAC in h1sush7, which h1susfc1 uses for its six M1 drives (T1, T2, T3, LF, RT, SD). Even though h1iopsush7 reported that DAC0 was driving correctly, there was no voltages being produced by the AI chassis.

We are in the early stages of figuring out what was wrong and how it got fixed. Due to HAM7 in-chamber urgency, once it started working we handed h1sush7 over the the HAM7 team.

Summary of what we did is:

tried various power cycles of IO Chassis and AI Chassis, no change. Put DVM onto DAC cable at rear of AI Chassis, looking at CH0 initially. No voltage. IOP correctly detected loss of AI.

With IO Chassis powered up, but computer down, Fil saw 3.5V on CH0, which went to 0V as soon as the computer was powered up. We are not sure this is normal behaviour, but we saw it on two different 20bit-DAC cards. 

Next we replaced the 20bit-DAC, no change. Old (removed) 210303-09 New (installed) 210303-14.

Erik reminded us that since this is the first DAC in the IO Chassis, we can test CH7 with the DUOTONE loop back (IOP feeds ADC0-CH31 directly into DAC0-7, switches relays on Interface cards which routes DAC0-7 into ADC0-30). We turned this on, ADC0-30 saw the DT. 

Next we replaced the DAC's ribbon cable and interface card. This make things worse, no CH0 signal and now no Duotone. Interface old (removed) S1101353, new (installed) S1000868.

Thinking that ribbon cables are more likely to fail than IF cards, we went back to the original IF card S1101353, installed another ribbon cable, and shuffled DAC0 over to the second Adnaco backplane. THIS FIXED IT.

Several changes were made here, so we are not sure if it was the slot move or the ribbon cable or both.

Here is the original card layout (not shown A4-1 = BIO0)

and here is the one we ended up with (ADCs shuffled one left in A2, 20DAC0 moved to A2-1)

We tested the first 6 channels (CH0-CH5) using h1susfc1 by untripping the watchdogs and driving the DAC with a FM offset of 10000, resulting in a 20bit-DAC drive of ~40000 counts, which gives 0.7V DAC output. CH7 was tested with the Duotone.

I was reminded that on the 1st December 2025 the h1iscex 18bit-DAC to 20bit-DAC upgrade failed with no drive on the new DAC. That was also the first DAC, and at the time we tested the DUOTONE signal (in fact DAC-DT is always on for CAL). In that DAC all the channels were not operational, and replacing the DAC fixed it immediately. So it looks like today's problem is different, and a much more insideous one because internally everything looks nominal but no voltage is actually sent by the DAC.

Shoshana, Alexandra, Jim, Arnaud

Today we completed the build of x4 HOQIs (D2500104), wired the capacitive plates of two CRS (following pinout from D2500389, with cap A = Left plate and cap B = Right plate), and hung one CRS with a dummy flexure.

Tomorrow we will align and tune the HOQIs, and hung the CRS with its final flexure.

A few things to note:
*We used undersize (0.0625" for 0.063" hole) dowel pins on the baseplate to set the alignment of the 4 BS cubes, then removed the pins from underneath the plate. While this was our plan B, it worked quite well (initial design was to use 1/16" spring pins, but they are hard to insert without bending them). 
*Some baseplates holes for the dog clamps were not threaded all the way through, we had to use washers to reduce the screw travel range. We will have to order a 4-40 tap and retap those holes.
*Some photodiodes cracked from screwing the setscrew in the holder (but we have enough spares). Details in the HOQI PD Testing tab of the spreadsheet attached to E2400153.
*For next time, we should make sure the photodiode vent hole is not aligned with the setscrew holding the photodiode in place (maybe update drawings D2600047)
*The waveplate holders were scribed with 4 lines for the 1/4 waveplate and 2 lines for the 1/2 waveplate so we can recognize them

Jonathan, Patrick, Erik, Dave:

We restarted the DAQ + EDC around 16:00 this afternoon primarily to install Patrick's new H1EPICS_HEPIPUMPL0.ini to match his new IOC.

At the same time we removed the end station VEA2 Dust monitor channels, there hasn't been a second dust monitor at the ends for some time and the Sat power outage required an EY Dust restart which removed its VEA2 channels from the ioc. We also made the EX INI change for when its IOC is restarted.

To green up the EDC, we temporarily removed h1susbs' FEC-31 channels. Erik has put H1EPICS_[FEC,SDF].ini under puppet control, so these will be added back when h1susbs is reinstalled.

We also fixed an issue whereby yesterday puppet added some incorrect KC0 channels to the EDC. This was fixed today and there are now no KC0 channel in H1EPICS_DAQ.ini, they all reside in the hand-built H1EPICS_DAQKC0.ini. Around today's restart time KC0 coincidently went unstable, restarting itself every 5 seconds. The problem was downstream of KC0. Jonathan contacted LDAS and the problem was fixed within the hour.

The EDC is green again, first time since the power outage.