Closes FAMIS#39855, last checked 89138

Corner Station Fans (attachment1)
- All fans are looking normal and within range.

Outbuilding Fans (attachment2)
- All fans are looking normal and are within range.

Now that HAM7 is at sufficient pressure (6.4E-7 Torr as of this post) we helium leak checked the two re-installed 12" CF blanks removed for table locking and the entire relay tube assembly which had been removed for the viewport adapter on HAM5.

The Helium background was unstable, so we turned on the HAM7 cleanroom (on 2/18 afternoon) to help flush the area of helium overnight.

Today the background stabilized around 1.5E-10 Torr-l/s, so we were able to continue leak checking. No significant helium signal observed above the leak detector background which hovered between 1.5&2E-10 Torr-l/s during leak checking. 

HAM7 continues to pump down with the turbopump, next steps are chamber RGA scans.

DAQ was restarted around 12:02 PM  PST after restarting h1ascimc. 

Thu Feb 19 10:12:02 2026 INFO: Fill completed in 11min 58secs

Yesterday afternoon Rahul centered the OSEM flags on JM3 (89187). This morning I took another set of transfer functions to check that they're looking good. Flags are well centered (pic), and transfer functions are looking good (TFs).

Settings:
- ISI Locked
- OFFSETs OFF
- DAMP OFF
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Data/2026-02-19_1645_H1SUSJM3_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
r12913
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/Results/2026-02-19_1645_H1SUSJM3_M1_ALL_TFs.pdf
r12914

Rahul, Fil, Oli

We still don't know why PM1 looks different now than it did when we installed it back in May 2025. Currently, we've nailed it down to two possibillities: (1) there's an issue with PM1 somewhere between the satamp and the in-chamber stuff, or (2) the December 2025 satamp swap to a modified satamp changed the magnitude of PM1 (we are not sure if this makes sense).

Here are some measurements we took yesterday and the things we've looked at so far.

Satamp

We were worried about the satamp, which is a dual satamp, swapped in in December 2025 (88590), with JM3 taking up the other half, so I took some transfer functions yesterday morning for both PM1 and JM3. I compared JM3 now to how it looked when we first installed it in December 2025, and it looks exactly the same, no drop in magnitude for JM (JM3 Dec2025 vs Feb 2026), and no increase in magnitude for PM1 (PM1 May 2025 vs Feb 2026).

Fil then swapped all the PM1 cables on the satamp with all the JM3 cables on the satamp. This made it so the only difference between the previous and these measurements is the part of the satamp used. These measurements for PM1 and JM3 still looked the same as the earlier measurement, so it's not the satamp (PM1 JM3 comparison). These comparison plots really show how much PM1 changed compared to JM3.

All other in-air electronics

The only other difference from the measurements last May for PM1 should be the coil driver, since the other one failed (88998). The new coil driver is modified, just like the old one, and is being correctly compensated for in the coil drive filter banks. To check this, as well as the rest of the in-air electronics, Fil swapped everything back to nominal EXCEPT for the cables that run from the sat amp out to the chamber. This way, JM3 is using the in-air electronics from PM1, and PM1 is using the in-air electronics from JM3. I did a few transfer functions looking for any difference but both suspensions and electronics chains still look the same(PM1 L, PM1 P, JM3 P). This could mean that the issue with PM1 is due to something in the satamp-to-chamber cable or in vacuum.

OSEMs

We checked the spectra for the PM1 BOSEMs but we did it while the purge air was up, so they're very noisy and not very useful.

Satamp question

The only other thing we can think of that could've changed the magnitude of PM1 but not affect what we're seeing in JM3 would be due to the satamp swap in December. The new modified satamp was hooked up to PM1 and JM3 on December 18, 2025 (88588). JM3 was first tested the next day, and obviously we never got a measurement of JM3 with an unmodified satamp, so if it's possible for the satamp to change the magnitude of PM1, that might be what is happening. I haven't had time yet to check whether other suspensions show anything like that.

Measurement info
PM1
2026-02-18 1600
- ISI Locked
- alignment offsets OFF
- DAMP OFF for measured DOF, ON for other DOFs
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Data/2026-02-18_1600_H1SUSPM1_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
12905
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Results/2026-02-18_1600_H1SUSPM1_M1_ALL_TFs.pdf
12909

2026-02-18 1715
- satamp inputs swapped with JM3 (tfs look the same)
- ISI Locked
- alignment offsets OFF
- DAMP OFF
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Data/2026-02-18_1715_H1SUSPM1_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
12906
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Results/2026-02-18_1715_H1SUSPM1_M1_ALL_TFs.pdf
12909

JM3
2026-02-18 1600
- ISI Locked
- DAMP OFF
- alignment offsets OFF
- DAMP OFF for measured DOF, ON for other DOFs
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Data/2026-02-18_1600_H1SUSJM3_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
r12904
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Results/2026-02-18_1600_H1SUSJM3_M1_ALL_TFs.pdf
r12908

2026-02-18 1730
- satamp inputs swapped with PM1 (tfs look the same)
- ISI Locked
- alignment offsets OFF
- DAMP OFF
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Data/2026-02-18_1730_H1SUSJM3_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
12907
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Results/2026-02-18_1730_H1SUSJM3_M1_ALL_TFs.pdf
r12908

Comparisons
PM1 May 2025 vs PM1 Feb 18 2026
/ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/Data/allhttss_2026-02-18_PM1_May2025vsFeb182026_ALL_TFs.pdf
r12911

JM3 Dec 2025 vs JM3 Feb 18 2026
/ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/Data/allhttss_2026-02-18_JM3_Dec2025vsFeb182026_ALL_TFs.pdf
r12912

JM3 Dec 2025 vs JM3 Feb 18 2026 vs PM1 May 2025 vs PM1 Feb 18 2026
/ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/Data/allhttss_2026-02-18_PM1_JM3_PM1looksdifferent_ALL_TFs.pdf
r12910

TITLE: 02/19 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: 17mph Gusts, 10mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.36 μm/s 
QUICK SUMMARY:

More HAM1 work today

I added this shutter (shutter H1:SYS-MOTION_C_SHUTTER_M) to the main shutters screen at sitemap->LSC->Shutters. I also added a menu button that takes you to the control screen to the sitemap->IOO->JAC Overview screen, see pic.

We locked JAC with 1W input to find ghost beams. Details will come after we're done with the septum window reflection, but anyway here is the list:

1. EOM AR reflection. Properly dumped today.
2. L1 reflections (front and back surface) are reflected by JAC output coupler and go through L1. Properly dumped today.
3. L2 reflections (front and back). Properly dumped today.
4. L3 reflections (front and back). Properly dumped today.
5. EOM wrong pol forward going beam. Changed the beam dump position today. This was brighter than I thought, we will measure the power again.
6. JM2 transmission. Already dumped, confirmed it's still there.
7. JM3 transmission. Already dumped, confirmed it's still there.
8. Septum window reflection. This was coming back horizontally in -Y direction, was about half inch off from the main beam at the top periscope mirror, and hitting the metal part at the top edge of the bottom peri mirror. Not dumped yet. 
   • We'll have to improvise something so the beam is dumped at the top periscope position before entering into the periscope structure. Something like a variation of the beam dump behind the top mirror of the  JAC input periscope. 

None of the new beam dumps are interfering with the main beam and JAC refl/trans.

Jennie W, Ryan S

Summary: Ryan and I updated the JAC and IMC ASC models. We installed JM3 yesterday and so now the IMC cannot use the PSL PZT mirror as an alignment actuator. I have committed the changes to the svn but erik and dave will do some checks tomorrow before they commit to the revision locked version of the model and restart the DAQ. So changes are not 'live' yet.

The edits were made to h1ascimc.mdl which has top level blocks for IMC and JAC.

The JAC top level model sends signals directly to the PSL PZT mirror and these degrees of freedom are swapped as the PSL PZT basis P and Y are switched before input to the JAC due to the HAM1 input periscope.

I took out the feedback paths for PZT_P and PZT_Y that come out of the IMC block. The picture shows the old config and I have highlighted what I removed.

At the top level, IMC no longer sends signals to the PZT but instead to JM3. On the top level diagram, the signal JM3_P is sent via PCI cards to the channel "H1ASC-JM3_YAW_SUSHTTS" as pitch in the JAC basis is yaw in the IMC basis due to the HAM1 output periscope. The picture shows the old config and I have highlighted what I swapped.

The signal JM3_Y is sent via PCI cards to the channel "H1ASC-JM3_PIT_SUSHTTS" as yaw in the JAC basis is pitch in the IMC basis due to the HAM1 output periscope.

Within the IMC top names block I removed the output channels for the PZT from the WFS feedback path, we already had paths to feedback to JM3 within this path. The picture shows the new config.

I removed the PZT locking path from the LCKIN block and replaced it with one for JM3. The picture shows the new config. I am not sure we ever use this path (which is for dither asc control of the IMC) in the first place so maybe this was unneccessary.

I also removed the channels H1:IMC-PZT_YAW_OUT and H1:IMC-PZT_PIT_OUT from the DAQ channel list for the IMC model.

SUS JM3 (Tip Tilt) update - This afternoon I went into the HAM1 chamber (when no one was working with the beam) and re-touched the BOSEM flags to center it with the LED/PD for half light. I will re-take TF measurements later on.

TITLE: 02/19 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: HAM1 work continued today
LOG:                                                                                                            

We refined the alignment from JAC to IMC by iterating small amount between JM2 and JM3. It was hard due to purge air and the suspended JM3, instead of relying on the IMC scan and minimize 1st order modes, we locked IMC and minimized the IMC REFL DC on average. After that the beam was still centered on JM3 well.

We closed the chamber and turned down the purge all the way and the alignment was indeed good. There was almost no 01 (PIT) mode power, 10 (YAW) mode power was less than 1% of 00 mode power, and the 20/02 mode power was 0.23 to 0.24%. See MM.png.

(To identify which mode is what, I intentionally misaligned JM3 in YAW (that causes PIT misalignment for IMC. See  mode_identification.png.)

J. Kissel

Executive Summary
Using 
   - the AxcelPhotonics butterfly diode laser,
   - the "beam splitter / near-field / bypass" measurement setup described in LHO:89123 to rapidly check the beam diameter at z = 0.991 [m] (near field) and z = 5.41 [m] (far field), 
   - elevating the beam height elevated to 5 [inches] to avoid any sort of clipping on other optomechanical setups on the table from other teams, and
   - loosening the lens position set screws only just barely, 
   - paired fiber collimators, in-vac feedthrus (with integrated patch cords), and ex-vac 7.5 m patch cables in-vac feedthrus 

      Beam Path   Char Date    Collimator   Feedthru (Pwr Transmission*)
      MEAS        2026-02-13   S0272503     S3228003 (100%)    
      REF         2026-02-17   S0272502     S3228002 (99%)    

      * Power transmission as reported from SWG:12296

I was "rapidly" tune the lens position, z_lens, for *both* the MEAS S0272503 and REF S0272502 fiber collimators to within 0.010998 (i.e. 11 [mm] - 2 [um]) with uncertainty of +/- 1 [um] , such that 

each fiber collimator sends out a free-space beam whose parameters meets SPI's requirements:
   - the desired waist radius (in both x/y dimensions) , w0 = 1.05 [mm], of within +/- 0.10 [mm], and
   - the desired waist position (in z), z0 = 0.0 [m] to within +/- 0.18 [m].

(where "rapidly" is in quotes: about 4 hours each from "install into measurement setup" and "I'm happy with a final full-position-vector scan). with no signs of strong astigmatism that I saw in the initial setup. (The later point confirms my suspicion that I was clipping on the EOM characterization setup, and there is *no* issue with the laser seed mode, polarization, or the beam splitters).

Support Media

The raw data from the beam profiles of each free-space beam are posted as
    2026-02-17_spi_fc_S0272502_ft_S3228002_7p5mPatchCord_AxcelPhotonicsLaser.txt
    2026-02-13_spi_fc_S0272503_ft_S3228003_7p5mPatchCord_AxcelPhotonicsLaser.txt

where the columns are jammt-friendly format of z Position [cm], Y waist radius [um], X waist radius [um]. 

Notes: 
    (1) as opposed to all previous data sets (e.g. LHO:89047, LHO:86350, LHO:84825) -- I added an additional measurement at z = 0.25 [m] to try to improve the accuracy of the fit beam.
    (2) X is "Axis 1" of the NanoScan parallel to the optical table, Y is "Axis 2," perpendicular to the table. As discussed in LHO:89099, jammt seems to import any three-column dataset such that the first column ends up fit as the "tangential w0," and the second column end up fit as the "w0." With a la mode, the data is typed in a matlab script manually, so X and Y data are modeled separately the entire time without rename, and thus kept consistent. Thus the intentional flip the X and Y axes in the text file such that a la mode and jammt are now both treating w0 = X = Axis 1 = parallel to table, and tangential w0 = Y = Axis 2 = perpendicular to the table.

I imported these beam profiles into both matlab (to run a la mode) and jammt to obtain waist radius, w0, and waist position, z0, fits to the AxcelPhotonics beam profiles, see attached plots:
    S0272502  a la mode  jammt
    S0272503  a la mode  jammt

Some pictures of the measurement setup with the NanoScan head at the new z = 0.25 [m] position (upstream of the beam splitter bypass):
    2026-02-13_FC_S0272503_S3228003_MeasSetup.jpg
    2026-02-17_FC_S0272502_S3228002_MeasSetup.jpg

Some pictures of the clean fiber collimator + vacuum feedthru systems packed up after measurement:
    2026-02-13_FC_S0272503_S3228003_PackedUp.jpg
    2026-02-17_FC_S0272502_S3228002_PackedUp.jpg

Detailed Analysis Results

Here's a table of the fit results from both a la mode and jammt. 


        

            

                
FC + FT S/N
Model
w0x [m]
z0x [m]
w0y [m]
z0y [m]
            
        
        

            

                
S0272502 + S3228002
a la mode
1.0392
-0.065196
1.0427
-0.020038
            
            

                
jammt
1.0392
-0.06521
1.0427
-0.02007
            
            

                
S0272503 + S3228003
a la mode
1.0396
+0.17704
1.0282
-0.030537
            
            

                
jammt
1.0396
+0.17702
1.0282
-0.03051
            
        
    
It's not a typo, the two fitting softwares agree to within the precision of the each display; +/- 10 [um] on both the waist radius and waist position.

From here on in this section, since I intentionally paired up fiber collimators and fiber feedthrus to match the last two digits of serial number, I'll refer to them as either "MEAS = S[...]03", or "REF = S[...]02".

From the table of fits, you see that the statement in the executive summary about the waist position, z0 = 0.0 +/- 0.18 [m], is defined expanded to cover the X axis waist position of MEAS = S[...]03 z0x = +0.177 [m]. But really, the other axis of the MEAS = S[...]03 FC+FT pair is at z0y = -0.031 [m], and the REF = S[...]02 FC+FT pair is within z0x = -0.065 [m], and the best z0y = -0.020 [m].
So the waist positions are really *quite* close to 0.0 [m]. 

Good. So let's use these numbers to do recast the fit (using jammt numbers only) into context:
    (1) Percent Difference between desired waist radius and final measured waist radius:

        REF, S[...]02 :: (w0x, w0y) = ([1.0392 1.0427] - 1.05) / 1.05
                                    = [-0.0102860  -0.0069524] 
                                    = [-1.0% -0.7%]
                    Within 1.050 +/- 0.1 [mm] = 1.050 [mm] +/- 9.5 [%] = [1.15 0.95] [mm]?
                    Both axes waist radius are a factor of 10x better than reqs.
        MEAS, S[...]03 :: (w0x, w0y) = ([1.0396 1.0282] - 1.05) / 1.05
                                     = [-0.0099048  -0.020762] 
                                     = [-1.0% -2.1%]
                    Within 1.050 +/- 0.1 [mm] = 1.050 [mm] +/- 9.5 [%] = [1.15 0.95] [mm]?
                    Both axes waist radius are a factor of 5x better than reqs.
        

     (2) Rayleigh Range:  

         (zR := pi * w0^2 / lambda)

         REF, S[...]02 :: (zRx,zRy) = (3.1886, 3.2102) [m]
         MEAS, S[...]03 :: (zRx,zRy) = (3.1911, 3.1215) [m]

         There's no requirement on where the Rayleigh range sits, but for a waist radius of w0 = 1.05 [mm], we would expect a Rayleigh Range of zR = 3.255 [m], and these values are at most z = -13 [cm] from that or 4% "short" of the target value. This doesn't really matter to SPI, as long as the Rayleigh Range is somewhere in between the ISIK breadboard and the ISIJ reflector 15.427 [m] away. The real requirement is the spot size at the ISIJ reflector, which we need to keep at the design value of 5 [mm] (whose value was determined with the original design waist radius of 1.05 [mm], and the acceptance that we didn't have enough room on the ISIK transceiver breadboard to install telescopic lens solutions to keep the spot size around 1 [mm] both within the transceiver *and* at the ISI reflector). 

      (3) Astigmatism: 

          A := (zRx - zRy) / (zRx + zRy)

          REF, S[...]02 = -0.003376 = -0.3%
          MEAS, S[...]03 = +0.011026 = +1.1% 

          Here, again, there's been no requirement on the astigmatism, but ~1% astigmatism doesn't smell too terrible. 

      (4) Spot size at 15.427 [m]: 

          w(z) = w0 * sqrt(1 + (z/zR)^2) 

          REF, S[...]02 :: (x,y) = (5124.569, 5155.038) [um]
          MEAS, S[...]03 :: (x,y) = (5194.496, 5075.909) [um]

          Recall the design value of waist radius at the ISIJ reflector, z = 15.427 [m], is w(z = 15.427) = 5 [mm]. As discussed in SWG:12273, that ADC noise with the large spot size is limiting the sensitivity of the pitch and yaw readout, as 

          dx/dTheta ~ sqrt(8/pi) L / w(z).
    
          But still, a 1.1% level of astigmatism -- which would result in a different sensitivity / noise performance between pitch and yaw, means that pitch is only ~2.1% worse than yaw.      

Great! We're good to go!

Or, rather, a better JM3 integration and PSL unintegration.

I made a temporary IMC_WFS_MASTER and IMC_WFS_OUTMATRIX_kk screen such that it's easy to route IMC WFS signal to JM3, not the PSL PZT, because I wanted something that works now.

However, right after I made what looks to be an OK screen, I realized that this doesn't work. PIT signal should be routed to JM3 YAW and vice versa. No fully-working IMC WFS until the next model update.

In addition, earlier today Daniel suggested to nuke PSL PZT from the IMC ASC (good idea).

If you want to revert back to the old medm, copy the backup

/opt/rtcds/userapps/trunk/asc/common/medm/imc/IMC_WFS_MASTER_BAK_20260218.adl 

to

/opt/rtcds/userapps/trunk/asc/common/medm/imc/IMC_WFS_MASTER.adl 

Wed Feb 18 10:12:42 2026 INFO: Fill completed in 12min 38secs

Gerardo confirmed a good fill curbside.

TITLE: 02/18 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: 3mph Gusts, 1mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.44 μm/s 
QUICK SUMMARY:

More HAM1 work today

This morning we have pushed the JAC EOM by about 0.6mm (using ~25 thou thick washers) in -Y direction, following the finding of last Friday (alog 89158). 

After that the beam was good on the input side plate (the beam is offset in +Y direction by 0.1mm) and was OK on the output side plate (0.5mm offset in -Y direction).

The beam position on the crystal itself should be ~0.13mm in +Y direction on the input face and ~0.36mm in +Y direction on the output face. The angle between the nominal path and the actual path outside of the crystal is about 0.6 degrees. See pictures and cartoon.

Calculation depends on the refractive index, I assumed n~1+deflection/wedge=1+2.35/2.85~1.85, but using 1.85+-0.5 instead won't change anything in a meaningful manner.

This is acceptable, the beam is more than 1.5mm away from the side face of the crystal, cannot remember the beam radius but it should be smaller than 600um if FDR is still valid, so it might be 2.5 beam radius or maybe more.