Kar Meng, Sheila

I walked FC1 back to it's original slider position 88602 while walking the two steering mirrors between the OPO and SFI1 to keep the beam transmitted towards ZM4. Once this was done the beam was hitting the beam dump meant to catch the reflection off the beam diverter from the IFO.  I touched the last mirror on the VIP, B:M4, to bring the beam towards the center on the iris in front of ZM4, and then Kar Meng was able to see a beam on the SQZT7 periscope.  

Before we started: ZM4: P -338.7 Y -1297.7 ZM5: -120 P -460 Yaw  We moved ZM4 +5 to get the transmitted beam onto the OPO IR PD, ZM4 -338 P -1297.7 Y, ZM5 -720 P 839 Y.  Then we were able to align the CLF to the cavity a bit better by watching the flashes on the scope.  We can see evidence of clipping as the ZMs drift in the purge air the transmitted power fluctuates,  

We adjusted the in chamber CLF refl steering mirror to center on the CLF top periscope mirror, and Kar Meng aligned the CLF refl shutter PD using mirrors on SQZT7.  We were able to see that the OPO was semi-locked on the dither lock, but this wasn't stable. 

Last week we found that some of the hardware on the EY wind fence had broken, which meant some of the main support wires for the fence were dangling free, weakening the fence and possibly further damaging the scrim in any future storms. The main failures were in the all thread that goes through the posts and attach the wire anchor points to the post. We had a limited window today to go and try to patch the fence this morning, so that's what Randy, Mitch and I did. Forecast promised us some sun, but that never really materialized, so it was pretty chilly. Fence is patched up now, Randy and Mitch will return the lift to LEXC this afternoon, after everybody thaws out. 

FAMIS 31117

Since I missed pulling these trends last week, I plotted a total of 17 days this time around. Overall, things look to be running smoothly. Robert was in the enclosure 6 days ago tracing cables, which shows clearly in the relevant trends. The PMC and RefCav have needed some alignment touchup since the power outage based on the beam images, so I'll do that either today or tomorrow before the holiday break.

Mon Dec 22 10:05:09 2025 INFO: Fill completed in 5min 5secs

I have added a link to the Vacuum section of the CDS web page which opens the latest Zeks dryer skid camera images. These images are running on the virtual FOM cdsws12, display=5. They are updated every minute.

Gerardo has placed a clock on top of the skid to give a timestamp.

link to image is:

cdsws12_5-1.png

Bypass will expire:
Mon Dec 22 01:07:27 PM PST 2025
For channel(s):
    H0:FMC-CS_FIRE_PUMP_1
    H0:FMC-CS_FIRE_PUMP_2
 

Closes FAMIS27623, last checked in alog88538

Laser Status:
    NPRO output power is 1.839W
    AMP1 output power is 70.55W
    AMP2 output power is 139.7W
    NPRO watchdog is GREEN
    AMP1 watchdog is GREEN
    AMP2 watchdog is GREEN
    PDWD watchdog is GREEN

PMC:
    It has been locked 12 days, 15 hr 38 minutes
    Reflected power = 25.34W
    Transmitted power = 105.7W
    PowerSum = 131.1W

FSS:
    It has been locked for 3 days 16 hr and 18 min
    TPD[V] = 0.5215V

ISS:
    The diffracted power is around 4.1%
    Last saturation event was 5 days 19 hours and 36 minutes ago

Possible Issues:
    PMC reflected power is high

TITLE: 12/22 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 6mph Gusts, 4mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.23 μm/s 
QUICK SUMMARY: Cold and foggy morning on-site. Lighter days of work planned for the next couple of days, but at this point here's the outlook:

• In-chamber work in HAM7 w/ SQZ beam
• HAM2 chamber cleaning
• Move platform stairs from EY
• Move Beirgarten cleanroom (possibly)
• Prep work in W-bay cleanrooms
• Transition to laser SAFE

Sun Dec 21 10:08:07 2025 INFO: Fill completed in 8min 3secs

Sat Dec 20 10:07:39 2025 INFO: Fill completed in 7min 36secs

Gerardo, Richard, Erik, Dave:

Over the holiday break we need to remotely view the operation of the Zeks Eclipse air dryer skid in the mechanical room to ensure no moisture gets into the LVEA chambers.

I initially setup a fisheye camera (a repurposed gate-cam), which gave a good view of the panel's LEDs and the mechanical gauges, but lacked the resolution to view the LCD display screen to see the Dew Point signal.

I then installed an Axis 214PTZ camera, which was able to zoom into the LCD display and read the values.

So we are now running both cameras side-by-side. 

sw-mech-aux was configured to have both ports 13 and 14 on the VID-LAN (10.106.0/24).

I ran two 60-foot cat5e ethernet cables from the vacuum rack (where the switch is located), over to the front of the Zeks skid, using the overhead mezzanine railing to provide a temporary "cable tray". 

Because the Axis camera is AC powered, we ran an extension cable from the vac rack to the base of the skid, passing it under the stairs to prevent it being a trip hazard.

Erik, Tony, TJ, Jonathan, Dave:

at 12:04 Fri 19dec2025 PST we had a MSR network switch failure which took down the network for all the front ends, the /opt/rtcds NFS server and Guardian.

The Brocade Ruckus Network Switch SW-MSR-H1FE-STK (1/3) was found to be powered off (no LEDs illuminated). This is a ICX7150-48-4X10GR-RMT3 48port unit with firmware version 08.0.95g.

This unit is being powered by a Geist power distribution box, which itself is UPS powered, so all power cords are ORANGE. A second switch is also being powered by the Geist, and both it and the Geist were powered up.

We disconnected the failed switch's power cord (as found it seemed to be well connected, not loose) and plugged it back in, the switch did not light up. We then ran a longer power cord to the main rack power strips, again the switch did not light up. We then returned to the original power cord from the Geist.

While we were scratching our heads planning the next move we noticed the switch was lit up. We think it took at least a few minutes to show signs of life after its power cord was inserted.

We then let it boot up, which took a suspiciously long time, we expected something like 5 minutes but it was actually close to 15 minutes. At that point the network was returned to all the systems attached to this switch.

At this point all the front ends had returned in their running state, except h1sush12 and h1asc0 which had persistent DAQ errors. We restarted these frontends.

Many Guardian nodes were disconnected from the frontends, so we elected to reboot h1guardian1. It came back up with no problems.

Currently we do not know why this switch powered down. If it happens again our options are:

1) power it directly from the UPS rack power strip (i.e. not from the Geist) and give it plenty of time to show it is powering up

2) replace it with a spare switch

[Kar Meng, Sheila, Eric]

We spent some more time today getting HAM 7 squared away after the VOPO swap.  This morning, we plugged in the new oven stage controller and tested out the new translation stage and cabling.  Everything worked as expected.  After we were done testing, Sheila moved the new controller to the SQZ cabinet for storage.

This afternoon we continued work with recovering alignment on the 1064 path in transmission of the VOPO.  Yesterday, we managed to roughly align everything in the chamber except for the iris before ZM4.  However, we ended up walking FC1 a bit to get the retroreflected beam from the filter cavity back through SFI1.  Today we started to slowly step FC1 back to its original position recorded in (88602) while walking the two steering mirrors on the VIP between the VOPO output and SFI1 to compensate.  We managed to get back to our original pitch position and about halfway back to our original yaw value while still keeping the beam roughly aligned through all aperatures up to the edge of the VIP.  However, we found that the beam coming off the VIP was still not aligned properly through the Iris in front of ZM4.  In fact, it had moved further in the -Y direction and is now clipping on the black glass beam dump for the FC1 wedge.  We were a bit disappointed at this point to find that we weren't making progress recovering the original SQZ path alignment.  

We then decided to turn on the FC 532 field to see if the 532 and 1064 FC paths were reasonably well co-aligned.  We were hoping that the 532 field might provide us with an additional alignment reference since, in principle, it should still be properly co-aligned with the transmitted 1064 field from the old VOPO.  However, we discovered that the FC green field was not well aligned to the iris we'd placed after ZM3.  It was about a quarter inch too low on this iris. Also, along the beam path right after the VIP, the 1064 and 532 fields are off from one another in both the horizontal and vertical directions.  Unfortunately, we did not think to double check the 532/1064 co-alignment carefully when we were setting up the irises using the transmitted seed beam from the old VOPO, so we're unsure of exactly what happened here.  A few thoughts:

• We didn't have time to look at the FC green retroreflection today.  If the retro beam is misaligned, that would confirm that the issue is with the FC green path rather than with our 1064 nm alignment reference. 
• Its possible that this path got bumped when we were swapping out the new cable for the VOPO translation stage.  That path was very much in the way of our arms when we were reaching back to the cable bracket on the ISI.  We should secure the new cable sooner rather than later to avoid bumping the path after realignment is complete.  
• We should check if the FC Green fiber collimator is secure.  We had to tighten down the CLF collimator mount yesterday when we discovered that it was loose.  

TITLE: 12/19 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: HAM7 work continued, JM TFs were taken, HAMs 3 & 4 and were locked, and a network switch went down around noon and took all the front ends with it. The PSL cameras were taken down for a measurement today and someone who knows how needs to bring them back up sometime.
LOG:                                                                                                    

• Jim locked HAM3 and HAM4 HEPIs and removed all 4 PEM support tube end caps to give Jason and I better access and direct line of sight for FARO surveying. Half (3/4s?) of the plates have been removed from HAM1 and HAM2 as well.
• 19:50 UTC Rahul finished TFs for JM1 and JM3
• 20:04 UTC A network switch went down, Everything CDS went white on the FOMS, all the watchdogs for SUS and SEI tripped, medm froze... 
  • Stuff started to come back around 20:46 UTC
  • SW-MSR-H1FE-STK is the switch that went down
  • Looking at the safe.snap for the JMs, their settings look as expected after coming back. Except for a JM1 filterbank change potentially (SUS)
• 21:11 UTC GUARDIAN reboot
• 21:30 UTC I started to recover SUS, SEI, and TJ helped with the GRDs
  • Two of the front ends didn't come back for a while, FEC 20 and 18 (ASCIMC and IOPASC)
• 22:15 A crew of a few people ran down Xarm, then Yarm

I made a new medm screen for the dust monitors so there's a single screen where you can see all of the particle counts for the site, and you can get to all useful dust monitor screens through this screen. I also added some shell command buttons to launch scopes of the individual DMs. Its located under PEM on SITEMAP.

This morning, I started taking transfer function measurements on the two new Tip Tilt suspensions (JM1 and JM3 for JAC) recently installed in HAM1 chamber. The screenshots are attached below - the chamber has a strong purge air flowing which created a noisy environment and I had to drive the suspensions really hard get a decent coherence. Travis dialed the purge air down, which helped (however, there were other ongoing LVEA work which were kind of saturating the DAC).

This is first of the many measurements to be taken (including osem spectra etc.), however JM1 looks great - ignore the magnitude for now and we will sort it out in the new year. The resonance peaks are where they should be - especially for JM1, just like how I tested it in the triples lab.

Similarly, JM3 is also behaving like how it was in the lab (RyanC took that measurement in the triples lab) -   couple of peaks on L and P dof are off by 0.15 Hz (due to longer wires, not much control here). Y dof has cross coupling from L dof at 1.25Hz, but if you look at this damped TF (when L and P damping were kept on) plot - the cross coupling is gone.  

More tests are in the pipeline and better results are expected, however this is a decent start.

The templates are stored at the following locations,

JM1

/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM1/SAGM1/Data/

2025-12-19_1820_H1SUSJM1_M1_WhiteNoise_L_0p02to50Hz.xml
2025-12-19_1820_H1SUSJM1_M1_WhiteNoise_P_0p02to50Hz.xml
2025-12-19_1820_H1SUSJM1_M1_WhiteNoise_Y_0p02to50Hz.xml

JM3

/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Data/

2025-12-19_2100_H1SUSJM3_M1_WhiteNoise_L_0p02to50Hz.xml
2025-12-19_2100_H1SUSJM3_M1_WhiteNoise_P_0p02to50Hz.xml
2025-12-19_2100_H1SUSJM3_M1_WhiteNoise_Y_0p02to50Hz.xml

 2025-12-19_2100_H1SUSJM3_M1_WhiteNoise_Y_0p02to50HzDampingON_LP.xml   - L and P dof damping ON during the measurement.

Purge air in HAM1 was set to its nominal flow once the measurements were complete.

R. Crouch, J. Oberling

Yesterday we began measuring the locations of the vacuum chamber support tube ends using the FARO laser tracker.  We started with the support tubes for the WBSC3 chamber and the +X ends of the WBSC2 support tubes as these were the most readily accesible.  The remaining support tubes in the LVEA (WBSC1, WBSC2 -X ends, and all WHAM chambers except WHAM7) have iLIGO-era PEM Interface Plates on them that block the support tube; some of these plates have undocumented spacers between them and the support tubes they are attached to, meaning we cannot accurately locate the support tube end w.r.t. the PEM interface plate and therefore making an accurate measurement of the support tube location impossible.  As an aside, Jim is in the process of removing these plates from the chambers (so far WHAM3 and WHAM4 are complete, WHAM1 and WHAM2 are 75% complete), so we can get at these support tube ends as the opportunity arises (he will then reinstall these plates, as they make for very convient mounts for dial indicators).

Measurement Method

This is a fairly straightforward measurement, but there is a somewhat subtle "gotcha" that needs to be accounted for to get an accurate measurement.  But first things first, we aligned the FARO to the LVEA's Building Coordinate system using our red alignment nests, then applied the X and Y axis rotations required to align the FARO to the site global coordinate system (see T0900340 for a brief overview of the coordinate systems in use).  We then loaded CAD models of the support tubes, that Ryan downloaded from the SolidWorks vault with each model in the site global coordinate system, into the FARO's control software, PolyWorks.  PolyWorks automatically reads the coordinate system information contained in the CAD files and places these models in position w.r.t. to the site global coordinate system.  This gives us nominal locations of the support tube ends, a guide for our measurements, and also a nice visual reference for where everything is positioned.

Now for the "gotcha."  The physical support tubes have a hole in the center of each end that is not represented in the CAD model, and this hole is large enough that the FARO target (a Spherically Mounted Retroreflector, or SMR, with a 1.5" diameter) sits slightly inside the hole.  This means that when you're taking a measurement of the center of the support tube end using this hole the SMR is not measuring the location of the actual support tube end, it is a few mm inside of it.  To account for this we did the following:

1. Use the SMR to get the coordinate corresponding the the axial length of the support tube on either side of the end and calculate the average (to remove any yaw in the support tube)
   • Using WBSC3 as an example, the support tubes lie parallel to the y-axis.  So we touch the SMR to either side of the support tube and record the y-axis coordinate, then calculate the average
   • We do this for each individual support tube end, as each one is slightly different
2. Use the SMR to get the same coordinate, but this time with the SMR sitting in the center of hole of the support tube
3. Calculate the difference between the two, to get the offset required for an accurate measurement
4. In the PolyWorks software:
   • Use the CAD model to create points representing the center of each end of the support tube
   • Create a line between each end point, representing the theoretical centerline of the support tube
   • Create a Measurement Point by offsetting the support tube end point along the centerline and to the inside of the support tube by the amount calculated in steps 1-3
5. Congratulations, you now have a measurement point that represents the nominal location of the support tube end, taking into account the offset required due to SMR positioning inside the center hole

To take the measurement we used the Build/Inspect mode in PolyWorks.  In this mode we have to be sure to select the "Towards Object" compensation method, which automatically compensates for the radius of the SMR (3/4", or 19.05 mm).  If "None" is selected the FARO measures to the center of the SMR, but our measurement point is at the edge of the SMR, since that's what is physically touching the support tube, so we need to compensate for that radius.  This gives us the deviations of the measurement point, which can then applied to the point representing the center of each support tube end to give their measured location.  The results of our measurements are shown in the attachment.  Since we had measurements for each end of the WBSC3 support tubes I also added a distance feature representing the measured length of each WBSC3 support tube.

Wrapping Up

Some points for discussion/further thought.  Keep in mind that the BSC support tubes are not exact representations of where their respective optics are; we only aligned the optic during aLIGO install, and in the end didn't really care where the support tubes ended up as long as HEPI had enough range to work.  This means that any deviation from nominal seen in the support tube ends is not an indication of misalignment of that chamber's optic.

1. The WBSC2 support tubes were supposed to be lowered by ~2.5 mm to account for the BS z-axis position being at -82.9 mm instead of -80.0 mm; this was done because, while the 4km arm cavities are flat in global coordinates the IFO input and output arms are not, so the BS had to be lowered to properly direct the beam (which rises in elevation while traversing the PRC) into the arms.  Therefore our expectation is that the WBSC2 support tubes are below the nominal z-axis coordinate of 1130.3 mm (we recently discovered that this change was not accounted for in the SolidWorks models for the sites).  While the global z-axis coordinate for all BSC support tubes is 1130.3 mm, if WBSC2 was lowered as required we would still expect to see a z-axis deviation in the measured points, but this is clearly not the case.
   • I was at LLO working on PRC alignment when the WBSC2 in-chamber alignment was started, so I have no memory of the initial positioning of the BS in-chamber; this was done by Hugh Radkins and Doug Cook (I had returned in time for pitch/yaw alignment).  Looking back at their notes they had to move HEPI +X by 4.6 mm, -Y by 2.3 mm, and +Z by 0.4 mm to position the BS, so this does not fully account for apparent lack of support tube lowering.  But as stated above, this does not necessarily mean the BS is too high (we'll know that for sure when we measure it once WBSC2 is opened in March 2026).
2. The measured length for the WBSC3 support tubes is shorter than their as-designed length of 3657.6 mm.  Not sure why at this point.
   • Once we get more full BSC support tube measurements we'll have more info to work from
3. The WBSC3 +X/-Y support tube end is a decent bit further in the +Y axis than expected.  Again, not sure why.
   • Looking back at my notes from install we had to move WBSC3 HEPI in the +Y dircection to properly place ITMx, so the overal deviation direction of these support tubes isn't a surprise.

This work was associated with LHO WP 12947, which also included the WBSC1 +X support tube ends.  Those support tubes still have PEM interface plates installed, so we are currently unable to measure them (will do in the future once the plates are removed).  Since we completed the rest of the measurements involved, I've closed the WP.