[Jim, Shoshana]

The CRS is currently aligned, suspended, balanced, and unlocked on HAM3!

I aligned each HoQI as well as I could on the table, HoQI2 is slightly better than HoQI1, but it shouldn't be an issue. I also lowered the resonant frequency as much as possible, but I ended up running out of mass that I could easily remove from the bottom, so right now the resonant frequency is at ~25Hz. It's possible this raised frequency is because these flexures (21, 22) might be slightly thicker than the previous ones as they came from a different batch.

Tested the picomotor, moving the X value positive moves the mass to the left (towards HoQI1). We had it do three revolutions in both directions and the picomotor was able to couple with the mass adjuster while at maximum range (tilting fully to either side). We've also discovered that the GS13s outputs go crazy when the picomotor is running, which is something to be aware of.

We've verified that voltage makes it to the damping capacitor plates on either side. We've also confirmed that in the HOQI{1,2}_DIST data increases as the corner cube gets closer to either interferometer (i.e. when the left corner cube (wing) gets closer to HoQI1, the HoQI1_DIST channel data increases)

Attached are various photos of the CRS on the table for future reference, as well as a guide to all the balance masses currently on it.

I tried to take full transfer functions for all 3 corner BSCs, I think BSC2 was the only set that completed. I will post those here. I think they seem ok. The high frequency stuff looks messy, but I think that is just because they are in air. When I get a chance I will compare these to LLO, out of time for tonight.

Summary: Things look OK (after some adjustments).

sliders.png is the latest snapshot of the suspension sliders.

What was done:

This morning, no SQZ reflection was visible in AS camera at all (except for SRM reflection). After getting confused, what I did was the following.

Make sure that SR and PR chain optics are aligned except SRM and PRM.

Asked Sheila to revert ZM4 back to the last the last known good alignment (Tuesday June 30 1300 Pacific, alog 90831). Reverted PR3, PR2, SR2 and SR3 back to the last known good alignment according to OSEMs. This only had a minor impact.

• Misalign ITMX, align ITMY.
• Moved ITMY until the ITMY reflection went back roughly to the old position on the AS camera (not on June 30 but earlier on June 25 in alog 90759 because there was not screenshot on June 30).
• Moved BS until the ITMY reflection went back roughly to the position I remember on the ISCT1 REFL camera.
• Align ITMX and move it until the ITMX reflection went roughly on top of ITMY reflection on both cameras. See PXL_20260707_193654789TS.mp4.
• Aligned PRM and saw PRC fringes (I won't call it flashing but it's a great sign).

As of now, F2 and F3 BS M1 stage DAC are using about 8e6 counts or about 6% of the full DAC range, everything else is smaller (DAC_now.png, top middle and top right).

It's worth noting that, before I did the above, I accidentally "aligned" ITMs and BS using a similar method as the above without knowing that SR2 was misaligned (SR2 had equivalent P and Y offset of 200/1.875~107urad and 300/2.681~112urad), and brought the ITMX and Y reflection into AS and ISCT1 cameras successfully.  Even then, F2 DAC output was about 12e7 or about 9% of the full DAC range (DAC_whenAlignedToMisalignedSR2.png).

The conclusion is:

We have plenty of headroom for BS DAC as of now, and even if our SQZ beam alignment is significantly different from "true" in-vac alignment, and/or the sqz injection path is not co-aligned with IMC injection path, BS can be tweaked accordingly to provide "true" alignment. 

Other things to add:

As of now, numbers don't add up in general, though that won't change my conclusion. If you want to disentangle the information, following is a summary table of the slider offsets, OSEM_DAMP_IN at the top stage, ISI (ST1 CPS) and HEPI (IPS) at the time of last good alignment ("back then") VS after I was done. All numbers are in urad.

ISI and HEPI Rz motions were used directly as YAW motions of the cage.

For Ry for ITMX and Rx for ITMY, the sign seen from the optic are the opposite. I flipped the sign of ITMY RX "diff" in the table such that positive "diff" for "PIT" for SEI for both ITMs means that the HR side of the cage points down. The sign-flipped numbers are followed with "(*)" in the table. If the optic itself just follows the local gravity without any change in the suspension, I'd expect "ISI+HEPI" PIT diff to be the negative of OSEM_DAMP_IN PIT.

For BS PIT, I gave up converting as it's a combination of RX and RY. 

For the numbers used, see ISI_HEPI.png for ISI ST1 CPS and HEPI IPS.  BS_ITMs.png and BS_ITMs_now.png show the top level OSEM_DAMP_IN and sliders, the only difference in these two plots is the time scale. In all of these, vertical marker indicates the last known good alignment on June 30, Y1 the "back then" level. A big jump in everything at t~-5d is the ISI unlocking, but the supensions kept drifting since.

BS sliders are uncalibrated, and OSEM numbers are not useful because they seem to have been reset at some point. Also I haven't bothered to convert ISI CPS RX and RY to BS cage PIT. So BS numbers aren't that useful except that YAW didn't move much.
ITMX PIT makes sense. SEI tilted the cage in PIT by 41urad (i.e. -41urad in top OSEM if SUS followed local gravity). SUS drifted by about negative 20 to 30 urad since then (ITMs_drift_after_ISI_unlock.png). I used the slider of positive 24urad to undo the drift to bring the PIT measured by SUS back to -41urad-ish. The PIT of the optic was brought back to "back then" level.

Other DOFs don't make sense to me. Nevertheless I'm not worried about the available range of BS actuation.

To repeat myself, we have both ITMX and ITMY reflection in both cameras, we see PRC fringes when PRM was aligned, and we were able to make the alignment OK even when SR2 was misaligned. Things look OK now and we have plenty of BS actuation range.

Now that we have finished with install and balancing of the ISI, I tried to do some basic check out of the ISI and found some cabling issues. The corner 2 actuators were crossed up, because the feedthru is labeled H2 and V2 on the ports, but the cables say coarse and fine. That was easy enough to fix. Corner 3 however, I can't get any drive on the H3 actuator. I checked the chassis is not overtemped and checked connections at the back of the chassis and at the feedthru. Connection is good, plugs are fully seated and the plug in the chamber is inserted right way up. The only thing I can think at this point is that I broke the wire in vacuum when I did the CPS swap. This will be annoying to fix I'm not sure what we have for spares either.

This will keep me from doing measurements of the ISI for CRS install and we definitely can't close this chamber until I can go into the nozzle between HAM3 and BSC2 to open the ISI up and look at the cable.

TITLE: 07/07 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: BSC1 DOORS ARE ON. Also CRS is installed!! LVEA IS LASER HAZARD
LOG:                                                            

IOT2 bellow put back on though they have a significant bend in them due to relative position of the table. I'd recomend checking if the beam is being clipped by the bellows. 
Adding tags like: REFLAIR, IMC-WFS,  IMC-REFL, IMC-TRANS so ya'll know what happened.
 

Rahul asked me to take some reference transfer functions on ZM4 before they go in and swap out the PSAM. I've done that, and these reference traces can be found in /ligo/svncommon/SusSVN/sus/trunk/HXDS/H1/ZM4/SAGM1/Data/2026-07-07_2030_H1SUSZM4_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml at r13056. The red traces are the newest measurements while the blue measurements are from when we did our last closeout checks in February 2026. ZM4 was IN HEALTH_CHECK during this measurement. 

F. Clara, R. Short

The shutter on the PSL table that blocks the SPI pickoff beam is currently being run with a temporary controller outside the PSL enclosure (see alog90490). This will eventually be connected to the shutter controller on top of IOT1R (the "JAC table") which is also controlling the shutter on that table, but this means running a 45ft cable from the controller box into the PSL enclosure and to the SPI shutter, the longest of these shutter cables we would use, so Fil wanted to test it. We took a spare shutter and the 45ft cable out to IOT1R and plugged them into the controller box. I guessed that the channel that would run this shutter was shutter N since the JAC shutter was M, and I was correct. I was able to successfully open and close the shutter with the long cable, so Fil will run it from the table to the PSL enclosure, where at a later date we will feed it through and connect it to the shutter on-table. Shutter N is still labeled as "Spare" and I was unable to change it, so I will need to ask for assistance changing the name in Beckhoff-space.

BSC1 North door has been installed and torqued.  Pumping on the annulus will begin tomorrow when we can get the scissor lift in place to access the platform.

Links to all of the B&K'ing that has happened this year to wrap up the vent. List is in reverse cronilogical order.

Rahul K, TJ S

Numerous beam dumps and other coated panels were added to HAM3 to mitigate stray light in the area. While we couldn't spend the time to test all of them, we chose the few that seemed like they would be the worst offenders.  The best map I know of for the newly added parts is in D2600134. Accelerometer locations marked on the last attachment of this log.

Accelerometer location 1 -  -X+Y corner of optical table. Acc dofs = IFO dofs

Meas 1 - On the table baffle mount in -X
Meas 2 - -Y 
Meas 3 - -Z

Location 2 - On the table next to the scraper baffle addition. Dofs = IFO

Meas 4 - Hitting the mount of the scraper baffle addition. +Y direction
Meas 5 - +X hit on same mount
Meas 6 - -Z on same mount

Since we couldn't mount the accelerometer directly to any of these new beam dumps and panels, we had to mount it to the table and pick up all of the other table noises. That said, I don't see anything terrible in these, so it looks okay to move on.

Ibrahim, Oli

Transfer functions before doors are on are attached.

/ligo/svncommon/SusSVN/sus/trunk/BBSS/H1/BS/SAGM1/Results/2026-07-06_1500_tfs

WP13304 HEPI Pump controller upgrade.

Patrick, Erik, Jonathan, Dave:

Patrick's new H1EPICS_HEPIPUMPEX.ini was installed into the EDC and the DAQ was restarted.

As with previous upgrades, some old channels have new equivalents, so to preserve recent minute trend lookbacks these channels were copied to the new name before the trend writers were started.

Sequence for the restart was

11:33 Stop TW0 and TW1

11:34 Copy raw minute files on TW0 and TW1

11:35 Restart 0-leg 

11:36 Restart EDC

11:40 Restart 1-leg

11:41 Two restarts of GDS1

Patrick is now running the new containerized HEPI Pump Controller IOC on the service-host cluster. Because some channels did not get renamed, my temporary edc_green_ioc was causing some channel duplication errors. Since we will be restarting the EDC tomorrow to sync to the new channels, for tonight I have removed all the temporay EX HEPI pump channels from edc_green_ioc. EDC has currently has a disconnect count of 253.

Note that the control room ALH alarm handler is alarming on old HEPI pump controller names. It needs to be updated to the new names.

Rahul K, TJ S

MC2 was unlocked, ISI and HEPI locked. 

Accelerometer location 1 - Roughly in the vertical center of cage on +Y,+X side. Acc dofs = IFO dofs

Meas 1 - Hitting -Y at the top of cage
Meas 2 - -X same area
Meas 3 - -Z top of cage, same corner

Location 2 - On the upper portion of the cage on the -X side. Acc dofs = IFO

Meas 4 - -Y on top corner of cage
Meas 5 - -X same corner
Meas 6 - -Z top of cage, same corner

When I get another minute, it will be interesting to see how these compare to the other triple suspensions that have these type of baffles.

The HAM2 East door A2F4 viewport failed inspection last week and was removed.  It was replaced with a re-inspected ZV-800 that was removed from HAM5 earlier this month.  See pics for SN, etc. 

The FCT bellows that was disconnected at the beginning of the vent was reattached to BSC3 port.

[Sheila, Camilla, Ryan, Eric]

We would like to verify that our recent mode measurements after ZM5 ( 90783) and before ZM4 (90815 ) make sense by connecting the two.  We decided to use the q value from the measurement at the nominal ZM2 strain in 90815 (ZM2 strain = 3.15V) and propagate that mode through the path containing ZM4 and ZM5 and calculate the overlap with the q values from 90783 measured at different strain settings for ZM4/ZM5.  The goals here are as follows:

1. Improve our model of the ZM4 - to - SEC path and verify that we're interpreting our mode measurements (with M^2 > 1) correctly.  
2. Determine the ROC for ZM4 and ZM5 as a function of the strain gauge voltage.  This is particularly important since we are going to replace ZM5 and Camille would like to know what ROC to shoot for with the pre-stressing procedure.

First, I address item 1.

Mode Measurements with M² > 1:

Our system seems to be adding some higher order abberations to the beam.  As a result, our mode measurements indicate that we have an M^2 number significantly above 1 (between 1.2 - 1.5 depending on the PSAM settings).  When M^2 is > 1, the presence of HOM content in the beam prevents one from focusing down to as tight of a waist, for the same divergence angle, the beam radius at the waist will be larger by a factor of M.  The thorlabs beam profiler accounts for this by fitting the data to the following formula (which we confirmed by doing our own independent fit):

w(z)² = w_M²[1 +(z - z₀)² (pi*w_M²/(M²*lambda))²]

Where w_M² = M²*w₀²  Is the waist for a beam with M²>1, and w₀ is the waist for the TEM00 component of the beam (ie for M² = 1). 

The q parameter ends up the same as before:

q(z) = (z-z₀) + i*z_R

where z_R = pi*w₀²/lambda = pi*w_M²/(lambda* M²)

Knowing that M² > 1 tells us that our beam is a mixture of TEM00 and some higher order mode content.  However, from the M² value alone we don't know which higher order modes are excited (in principle one might be able to make some rough projections using the surface abberation measurements of the PSAMs from Caltech, but that sounds tricky and is beyond the scope of today's post).  If we want to do mode matching calculations, the only thing we can do at the moment is back propagate the TEM00 component and do all mode calculations for TEM00.  

We use the same beam propagation matricies as always to back propagate the TEM00 component to determine what the TEM00 mode looks like in HAM 7.  

Determination of the ZM4 and ZM5 ROCs

I then took the q value (for the nominal ZM2 = 3.15V) from the measurement before ZM4, back propagated it to ZM4 using our length measurements.  I then propagated the q through ZM4 and ZM5 and calculated the overlap with the q values measured after ZM5 for various values of the ZM4/ZM5 strain gauge settings in ( 90783)

Then, the ROCs for ZM4 and ZM5 were chosen for each strain gauge settings to maximize the overlap.  The overlap is => 98% over the entire 2D grid of ZM4/ZM5 strain gauge values, which gives us some confidence that the ROC values are accurate.  One thing that gives us pause is that the change in ROC for ZM5 doesn't appear to change linearly in diopters with the strain gauge reading.  ZM4, on the other hand is roughly consistant with a 5 mD/V change though because the beam spot is quite small on ZM4, we are relatively insensitive to its ROC value.

These values give the following overlaps for the x and y direction (our mode measurements indicate we have non-negligible asitgmatism on this path) for propagating the nominal q value from (90815 where ZM2 strain = 3.15) to the q vales from ( 90783) .

The fact that this set of ROC values gives good overlap over the entire 2D grid suggests that these ROCs are a resonable model for ZM4 and ZM5 at these strain gauge settings.

Attached is an a la mode file for doing the beam propagation.  One could do some more intellegent fitting of the data to extract the best ROC estimates; I'm just sorta hand fitting it at the moment.

Eric, Ryan S, Camilla, Sheila

All week we have been working on getting a set of OMC scans and beam profile measurements for different psams.  We have both sets of data now, with plots and scripts coming soon next week.  

OMC scans

We started with a script that Begum gave us from HAM6 work at LLO.  We set up ASC loops to go from ASA and AS B DC signals to ZM4 and ZM5 (as described in 90742).  We struggled a while to lock the OMC on the seed beam in air, hampered by 90754.  With that noisy OMC lock, yesterday Camilla manually aligned OM3 and the OMC suspension carefully to maximize the 00 transmission.  We then added offsets to H1:OMC-ASC_QPD_{A,B}_{PIT,YAW}_OFFSET, which is not the usual location for OMC QPD offsets.  We will need to get rid of these offsets before we go back to locking. 

OMC A offset: PIT 0.088 YAW: 0.133  OMCB offset: PIT 0.27 YAW: -0.22

We found that we were able to move the psams, whih misaligns the OMC terribly, run the centering loops to the ZMs, then run the OMC QPD loops to bring the 1st order peaks back down to a couple % of the 00 peak repeatedly.  We spent some time modifying and then debugging the script that Begum shared with us.  

It takes in a list of ZM4 and ZM5 strain gauge values, moves the psams servos target to that point and waits 30 seconds with the ZM centering loops on (it doesn't check the acutal value of the strain gauge, perhaps this would be a good thing to add next time).  It then turns on the OMC QPD loops for 20 seconds.  It then takes a 100 second ramp of the OMC PZT, and saves the times and ZM strain gauge targets into a yaml file.  

There is a template you can use to watch all this at userapps/sqz/h1/Templates/ndscope/OMC_psams_scans_monitor.yml  The script that runs these sweeps is at sqzutils, or /ligo/gitcommon/squeezing/sqzutils/omc_scans_sweep_psams.py  There is also a script there that loads the data, identifies the peaks and estimates mode mismatch and misalignment there, analyze_psam_omc_sweeps.py.  A preliminary plot is attached (apologies for the color choices and linear y scale here).  

M2 profile measurements

Eric and Ryan S took a series of M2 profiler measurements of the beam on SQZT 7 today, doing the alignment procedure at each strain gauage setting (they didn't adjust ZM alignments).  Their data is in here, we will post some plots of this next week.

Note about ZM5 strain guage

While Eric and Ryan were making beam profile measurements, they ran into a situation where ZM5 would not go the strain guage setting of 2.  I was able to get it to go to 2 manually, but noticed that there were times when the strain gauge voltage dropped to zero, similar to a problem seen at LLO HAM6 recently.  We should follow up on this next week.

[Begum, Camilla, Ryan S., Madi, Sheila]

Measurements taken on 2026-06-08 and 2026-06-09:
After the new OPO installation, beam profiles measured on HAM7 table (Sheila 90345) indicated that the OPO mode is different for the new OPO. This of course would both affect OMC mode matching as well as FC mode matching. The following measurements are beam q-parameter measurements measured on the FC path (green path in attached diagram), for beam upstream of ZM2 (p6,p7,p8,p11,p12) and downstream of ZM2 (p9,p10). The camera/profiler used is Phasics SID4 (MIT unit). 

Phasics camera is capable of giving us a beam waist and how far away that waist is from the camera position (- upstream of cam, + downstream of cam), however the fidelity of these values are dependent on where the camera is placed with respect to the waist: if it is too close to the focal plane (where the beam divergence is small), or if the beam is too large for the sensor the extracted values don't make sense. So, we have measured at least two positions with known distance from each other evaluate the fidelity q parameters obtained. 

Multiple measurements were taken at p10 point, varying ZM2 curvature. The strain gauge values are given in the table, 1.2 V and 6 V strain gauge correspond to 0 and 200 V pzt supply voltage to ZM2 psam. For points p6,7,8,9,10 the A:L2 lens was sitting in the "middle" position, both edges of the stage is lines up with its rail (will add photo here). Below table is from measurements taken on 06-08. The camera reports three numbers for each parameter, major, minor, radial. Major and minor do not necessarily line up with horizontal and vertical axes. The screenshots for each case report what the angle is. The .txt file for each data point also reports wx and wy for the near field beam, so we can potentially infer from there.

There are two readily available beam parameter tuning options we have for the FC path: the ZM2 curvature via psam, and the A:L2 lens via the translation stage it lives on. In the afternoon, we parked the Phasics camera on p11 and p12 positions (between p7 and p8) and recorded beam parameters for A:L2 lens on three positions (middle:0mm, -13mm: lens closer to ZM1 by 13mm, +17mm: lens further away from ZM1 by 17mm). Below table is from measurements taken on 06-09.

Raw data is in the attached .zip