[Daniel, Kar Meng, Eric, Sheila]

This afternoon, we continued with the realignment of the VIP after the VOPO swap.  When we first started, we briefly lost the CLF input alignment between the fiber and the VOPO cavity.  It turned out that the collimator was loose in the mount.  We took out the collimator holder and noticed that the 2nd grub screw hadn't been tightened all the way.  After fixing, we realigned the cavity till we could see a reasonably strong beam in transmission while the cavity was scanning.  

We then began the painful process of aligning the weak transmitted beam through the various components in HAM 7.  Using only the first steering mirror between the VOPO and SFI1 on the VIP, we managed to get the beam roughly aligned up to FC1.  However, we couldn't quite figure out how to get the return beam from the filter cavity retroreflected through SFI1 again.  We eventually decided to move FC1 a bit to get the beam back through SFI1, through SFI2, and onto the iris right before ZM4.  We're thinking of doing the following to finish the alignment process:

• Walk the alignment a bit more to get to the beam diverter and onto the 1064 trans PD on SQZT7
• Optimize the alignment of the seed to the VOPO using the PD
• Dither lock the seed and finish aligning the SQZ path on HAM 7 with the brighter beam.  We will need to revert the FC1 alignment at some point.  Initial settings before we started tweaking things:  
  • H1:SUS-FC1_M1_OPTICALIGN_Y_OFFSET = - 153
  • H1:SUS-FC1_M1_OPTICALIGN_P_OFFSET = 232 

Betsy, Rahul

We found that SUS JM1 had a faulty quadrupus cable, which we replaced it today. Next, I took OLC for both JM1 and JM3 in HAM1 chamber. I applied the offsets, gains and then centered the BOSEMs - and they look good. Next, I will start checking the health of the electronics chain and the suspension itself (i.e. by taking the transfer function measurements).

The offsets and gain for JM1 is recorded in this screenshot - accepted in the SDF (safe).

The offsets and gain for JM3 is recorded in this screenshot - accepted in the SDF (safe).

For the upcoming ISS array swap, we plan to bypass the IMC, which is known to be a pain, but we need a stable beam for the array alignment.

Once the corner volume is vent, we use the QPD on the old array and IMC-IM4_TRANS as the initial reference for bypassing the IMC. Once IMC is bypassed, we will center REFL WFS BEFORE removing the old array and record the RM1/RM2 PIT and YAW. This way, even if we somehow suspect e.g. the pointing of the beam going to the IM4 moved after removing the old array, we can still restore the pointing by looking at the REFL WFSs in addition to IM4.

We measured the beam positions on these QPDs today even though we'll repeat this later.

IFO configuration:

• IMC was locked with 2W.
• REFL beam diverter was closed so no light comes out. (POP bdv was also closed just because.) 
• The cover on the REFL septum window was removed.
• PRM, all IMs and RMs are aligned. (Watchdog of RMs were reset.) ITMs are misaligned.

Arrow ("->") means before and after the REFL centering servo (DC1 and DC2) was turned ON:

Septum cover is left OFF but the PSL light pipe was closed after this. REFL centering was turned off but I didn't bother to offload the ASC output to RM sliders.

REFL WFS nubmers as of now are not super meaningful as we'll still have to lock HAM2 down, which potentially change the relative alignment between HAM1 and HAM2. (But it's good that the beam is still hitting REFL WFSs after HAM1 was locked down even though Jim noted that the ISI position of HAM1 is not good. )

I'll open the light pipe tomorrow and quickly repeat the measurement after Jim locks down HAM2 HEPI.

Closes FAMIS 27648, last checked in alog 88314

Trends look fine!

Thu Dec 18 10:10:58 2025 INFO: Fill completed in 10min 55secs

Rahul, Oli

Fil swapped out the JM3 / PM1 satamp this morning (88588) to the modified satamp (modified for ECR E2400330). I used my script python3 sustrunk/Common/PythonTools/satampswap_bestpossible_filterupdate_ECR_E2400330.py -o JM3 PM1 to update the satamp compensation filters in the OSEMINF and WD_OSEMAC_BANDLIM filter banks from 10:0.4 to the precise compensations for each OSEM.

I loaded these filters in and committed thefilter file as r34282.

Note that the satamp swap and the satamp compensation value update will change the perceived location of the OSEM OUTs

Fil, Rahul

This morning we replaced the unmodified Satamps for JM3/PM1 (both TT suspension) with the modified version - as per alog 88584. Given below are the details,

Old satamp s/n - S1200173

New Satamp s/n - S2500407

The adc counts of the bosems on JM3 and PM1 have dropped by 25% approximately due to the above change, hence we will have to compensate that on the filter side (Oli is currently on it). 

Also, we have swapped the cables for JM2 (mount) with JM3 (SUS TT) in the CER - as per alog 88584, this is now consistent with the wiring diagram.

I ran the pumps at the mid stations this morning to exercise the bearings and seals. This will result in an increase to the glycol loop temperatures in the trending. This increase will return to normal by the end of the week. 

TITLE: 12/18 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: 13mph Gusts, 10mph 3min avg
    Primary useism: 0.06 μm/s
    Secondary useism: 0.36 μm/s 
QUICK SUMMARY:

IFO is in IDLE for PLANNED ENGINEERING

A look at today's activities (extends to Fri)

• HAM7 Scattered light investigation, IMC locked beam out of HAM5
• HAM1 Continued investigation into JM1/3 OSEM/controls issues
• HAM2 Move IOT2L away from chamber
• HAM2 Lock HEPI
• HAM2 Removal of PEM Support tube plates
• HAM4 AIP work, pumps on and off
• South Bay crane pendant work
• BSC2 Prep work in West Bay cleanrooms and platform

M. Todd, G. Vajente, L. Dartez

Wednesday 12/17

1. Additional optics mounted
   1. ZnSe 2” lens
   2. 2” silver and gold flipper mirrors (not installed)
   3. Additional beam dump for reflection of Polarizer2
2. We had the PD chassis milled out further to take an offset out that prevented the board from sitting flush.
3. We noticed that the coating had been burned on the first beam sampler we got from EdmundOptics. Emailed vendor to ask if this is common, because the power density is not at all expected to have produced this.
4. We also took beam profiles with a rail installed to get a fit of the beam evolution between M2 and M3. I made a fit of the data, assuming that M2 was perfect (I was having trouble with the nonlinear fit without M2=1, will revisit).

To do tomorrow:

1. Try and compare the lens solution to the fitted q we have from measurements.
2. Try and set up the coaligned visible laser

[Sheila, Robert, Eric, Daniel, Karmeng]

By blocking and unblocking the beam from the OFI heading into HAM7, we see 1uW on H1:IOO-OFI_PD_A_DC_POWER, which is measuring power after a 99% splitter (B:BS1, E2000450, 99% reflective for s pol light at 45% AOI).  

Scattered light entering HAM7: average of 25.66uW and STDev 1.066uW. Single bounce from IFO, with input power of 9.2W. With 9.2W on PRM we expect 9.2W * 0.03 (PRM) *0.25 (BS) * 0.32 (SRM) = 22mW incident on the OFI, so this implies that the leakage towards HAM7 is 0.1% of the beam incident on the OFI; 29dB.  This implies that the isolation of this path from the main beam is better than what we infered assuming 1% transmission from B:BS1 in 87350, and is close to the isolation assumed in T1800447.  

We also measured the polarization of the beam by measuring the beams after they hit the polarizer on SFI2.  Consulting the diagram on page 8 of T1900649, this polarizer is set to transmit vertically polarized light and deflect horiztonal to hit the aperature which isn't labeled in the diagram.  We measured the beam between the rotator and the second polarizer (B:P1),after the aperture, with average of 14.07uW and STDev of 1.587uW.   This implies that the beam coming from the OFI is 55% vertically polarized.

Revisiting 87318 in light of these measurements.  If the polarization and splitting ratio of B:BS1 in full lock is the same as single bounce, this implies that we had 0.75mW scattered towards HAM7 from HAM5 in full lock.  Using the 4% transmission of this diode (and assuming that 30% of the AS light is carrier, which I want to double check), we need a reflectivity of 3% from some scatter source after the beamsplitter to explain the 12nW of scattered light reaching the DCPDs.  

  The thin film polarizer on the OFI should have an extinction ratio of 1:10,000 E1900285.  Also, in 88105 I moved the temperature of the OFI while we were locked and saw that we couldn't significantly decrease the scattered power that way.  

Fil, Oli

The JM1 and JM3 filter banks were populated, with some things that need updates found along the way.

JM1 and JM3 were populated based on PM1's filter banks. The only banks that aren't the same as PM1 are the OSEMINF and WD_OSEMAC_BANDLIM satamp compensation filter modules and the COILOUTF filter modules.

First, I filled out all the filter banks as a direct copy of PM1 using python3 /ligo/home/oli.patane/Documents/WIP/copySUSfilters.py PM1_M1 JM1_M1 (then replacing JM1 with JM3). This script copies over the filter modules in OSEMINF, COILOUTF, WD_OSEMAC_BANDLIM, WD_OSEMAC_RMSLP, LOCK, and DAMP filter banks. However, the OSEMINF,  WD_OSEMAC_BANDLIM, and COILOUTF filter banks are not the same as PM1, so those need to be updated.

OSEMINF and WD_OSEMAC_BANDLIM filter banks
In November (88162) the JAC electronics were installed and the satamps that were suppposed to be installed were S2500406 for JM1 and S2500407 for JM3 / PM1. Both of these are modified satamps per ECR E2400330. JM1 had the correct satamp installed but JM3 / PM1 had S1200173 installed instead, which is not modified and has a different frequency response. 
JM1 - JM1 has the correct updated satamp, which Jeff measured the frequency response for each chassis' channels for, so I updated the compensation filters for JM1 with the exact compensation based on the measurements for each channel. I ran python3 sustrunk/Common/PythonTools/satampswap_bestpossible_filterupdate_ECR_E2400330.py -o JM1 to fill out each OSEMINF FM1 and WD_OSEMAC_BANDLIM FM6.
JM3 / PM1 - On the flip side, the compensation filters for JM3 and PM1 are the same as what PM1's have been - 10:0.4: zpk(10:0.4:1) in OSEMINF FM1 and WD_OSEMAC_BANDLIM FM6.

COILOUTF filter banks
The coil driver for JM1 is S1106042, and the coil driver for JM3 is S2500411.
The PM1 coil drivers have had ECR E2200307 done, which affects the filter in FM6, and I've been searching to see if I can verify whether the JM coil drivers have had this (or the expansion ECRs, E2200307 or E2400048) done to them.
JM1 - The e-traveler doesn't mention it having been modified, just that it was taken out of production and replaced with a modified one (64166). I haven't been able to find anything anywhere that mentions that it ended up getting modified, so I am inclined to think that it might not have this modificiation. Thus, for now I am installing the filters that work for the unmodified driver. These filters are:
    - AntiLPM1: zpk([0.9;211.883],[9.99999;20.9999],1,"n")
JM3 - The e-traveler for the driver says that it's been modified per T2100410, which is the modification that is done as part of the ECRs mentioned above, so JM3 coil driver is modified and thus has the same AntiLPM1 filters as PM1. These filters are:
    - AntiLPM1: zpk([0.5;3174],[52.32;50.77],1,"n")

JM1 OSEMINF, WD_OSEMAC_BANDLIM, and COILOUTF filter banks, COILOUTF AntiLPM1 foton

JM3 OSEMINF, WD_OSEMAC_BANDLIM, and COILOUTF filter banks, COILOUTF AntiLPM1 foton

All of these filters have been loaded in and commited to svn as r34277.
We are hoping that the modifications they are supposed to have will be able to be done soon.

Erik, Rahul, Jeff, Fil, Oli

Earlier today we realized that the JM3 model ADC inputs did not match up with the cabling documentation. The documentation lists the order of the OSEM PD inputs into the AA chassis as JM1: CH 0-3, JM2: CH 4-7, JM3 CH 8-11. However, the h1susham1 model had the inputs for JM3 as CH 4-7, accidentally forgetting to leave room for the maybe-one-day JM2. This resulted in a bit of confusion until we figured this out. We temporarily moved the JM3 OSEM PD to AA chassis cable into the CH 4-7 inputs to match with the model so installation work could proceed, but once they were done we wanted to change the model to match up with all the documentation we had. To do this I just edited the h1susham1.mdl file and changed the JM3 ADC numbers from 1_4,1_5,1_6,1_7 to 1_8,1_9,1_10,1_11 and committed the model as r34274 (before, after). I then also updated susjm3_overview_macro.txt to have those adc number match and that was committed as r34275.

Erik restarted the h1susham1 model and everything came back fine (88581). Since earlier we had swapped the OSEM PD cable for JM3, the JM3 readouts currently look like nothing because we still need to swap that cable back to its correct spot tomorrow.

[Daniel D, Kar Meng, Sheila, Eric]

Today we continued with the VOPO install.  The pump beam is now aligned to the cavity.  Unfortunately, the cavity axis was different enough that we had to walk things quite a bit to optimize the alignment.  We double checked the mode matching for the pump path with the new cavity and it is sitting at around 85% with 15% in the bullseye mode.  

We also roughly aligned the CLF path by aligning the CLF reflection to the green transmission.  We then switched to the seed beam with the injection power turned up all the way and were able to see a beam on the card when the cavity is scanning.  Currently, the transmitted beam is clipping on SFI 1.  We will continue with the alignment tomorrow and finish optimizing the seed beam once we can get far enough down the SQZ path to reach a PD. 

I've updated the saturation thresholds on SATMON for the following suspensions which have had their DAC cards upgraded to 28bit earlier this week. I still have to add JM1 and JM3.

RM1 (M1)

RM2 (M1)

PM1 (M1)

IM{1,2,3,4} (M1)

PRM (M1, M2, M3)

PR3 (M1, M2, M3)