Thu Jan 22 10:05:43 2026 INFO: Fill completed in 5min 39secs

Jennie W, Rahul K, Jason O, Keita K

Rahul and Jason installed body mode dampers on the JAC, we did not expect it this to change the position of the JAC much.

Thinking of what could have cause this there are two possibilities:

1. Installing the body mode dampers moved the JAC.
2. The B & K hammering on Tuesday (see alog # 88822) of the input HAM1 periscope somehow shifted its mirrors.

After installation we tried to lock and could not. Checking the output of the JAC we could not see flashes. Lookign at the input coupler of JAC on a card the beam seems high coming into the JAC.

Jason and I recovered the alignment into the JAC somewhat with the PSL persicope PZT and the "JM1" fixed mirror which sits right after the HAM1 input periscope.

We finally managed to lock the JAC (altered the guardian timeout thredhold which checks the power level - I marked what I changed in the code so I can reverse it).

Below I include a comparison of the last time we were locked last Friday 16th, this is nominally in mW but we have not checked the calibration of this PD yet.

Yesterday afternoon we took this image of the locked level and it is worse by a factor of 2, see this image.

Keita suggested we do a scan with the on board PZT while the cavity was unlocked.

Taking the measured hom spacing which Masayuki and I measured in this unit at CIT, 1.75 radians and the FSR, caluclated from 1/time period between TM00 modes, we estimate the 01 mode is 0.75 of the FSR.

The scan of the transmitted beam in blue makes it look like we have two candidates for this 01 mode that are between 70 and 50% of the height of the TM00 mode, so we are most likely mis-aligned. The scan voltage is in red.

Last week we had aligned into HAM2 and out of the viewport that normally delivers the beam to IOT2L. We checked this late in the afternoon and the beam gets through the MC REFL periscope on the table and through one mirror, then clips on BS1.

This makes it likely that our output alignment has not changed badly and so we can go ahead with aligning the output of the JAC.

Our plan today is to spend half an hour checking the JAC is not locking to a HOM and then try and improve the alignment ontpo IOT2L with JM2 and JAC_M3 mirrors in HAM1.

We still have irises at the output of the HAM1 table, one of which was placed at the old output beam position before we installed the input periscope or the JAC cavity, so we will try and improve the line through this iris and onto IOT2L.

Yesterday the EOM arrived midday, Keita and Rahul concentrated on building this in the optics lab, this will continue to be worked on today.

Per WP12989 we completed the EOM cable install from PLS-R2 to the HAM-1 feedthrough.  The old EOM cables from the PSL were disconnected at the patch panel, and the RF Combiner was powered down.  RF Cables were landed at the patch panel from left to right, 24MHz, 118MHz, 45MHz, 9MHz, with 2 empty spigots on the right hand side of the panel located at U2 in the rack near the floor.  We will shoot these with the TDR to once everything is installed to get total electrical length for calibration.

M. Pirello, F. Clara

TITLE: 01/22 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: 5mph Gusts, 3mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.17 μm/s 
QUICK SUMMARY:

• HAM1 work today, EOM installation and JAC mode matching
• A 4.7 from Wyoming rolled through ~3 hours ago
• The LVEA remains in LASER HAZARD

TITLE: 01/22 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: OPO and JAC work continued in HAMs 1 & 7 in LASER HAZARD.
LOG:                                                                                                                                                                                                       

19:24 OPO WD trip

FAMIS 31121

Things are looking very stable over the past week; makes sense since very little has been asked of the PSL recently. The PMC and RefCav could still use an alignment touch-up, which I'll get to hopefully this week.

Jeff, Oli

We decided to rename the SR3 OPLEV Whitening to AA chassis cable from SUS_SR3-168 to SUS_OPLEV_SR3_AA. We decided to do this for a couple reasons: SUS_SR3-168 is not a very helpful name, it matches better with the other OPLEVs' cables, and anyway we had already been calling that cable SUS_OPLEV_SR3_AA in our wiring diagrams for a while. 
We relabeled both sides of the cable.

[Sheila, Ryan, Karmeng]

We have returned ZM2 to the original position at the beginning of O4, we alleviated some of the saturation but the ZM3 iris still require adjustment.

Power budget looks good so far. With 0.77mW exiting the OPO and reaches AM3 at the same power. We observed 0.75mW of OPO trans and 18.1mW of OPO refl on SQZT7 periscope.

Jason. JennieW, Rahul

This morning we added the damper parts to the JAC in HAM1 chamber - see picture attached. The cables were re-routed slightly so that they don't interfere with the damper.

I have finger tightened the screws of the damper for now - since no torque spec was provided and we were worried that tightening them too much might affect its position/angle.

Yesterday I picked up the shipment from LLO contain the 2nd HXDS (first HXDS shipment alog87998) and related ASSEYs and brought it to the Triples lab. 

Uwrapping and inspecting was uneventful, the zip ties were intact, the shock pads untripped and the humidity indicator was unchanged in color. The outer (front, back) and inner (front, back) bags were in good condition, unwrapping the suspension I found no play with the blades.  All the nuts and dowel pins were tight and well seated, the ICS looks good except for it seems to be missing the HDS Intermediate Mass Fixture (D2000230-V1, s/n 08). The part is scribed as V1, on the dcc there's a V2 with two added 8-32 helicoils taps that, based on D1900352 which uses V2, I should be able to see from the front and I don't, so this is a V1 plate and not an incorrectly scribed V2. I believe these two missing 8-32 holes are where we will attach the BOSEM Mounting plate (D2000257). The first HXDS we received in November had the V2 plate. We may have to do a small rework to update it to V2, or have LLO send the V2 part if possible.

The pre-filters were replaced in the FCES air handler. 

Wed Jan 21 10:08:13 2026 INFO: Fill completed in 8min 10secs

Closes FAMIS#39334, last checked 88680

The elevated sensors listed are just from HAM1 and HAM7, which is expected
All chambers are looking normal relative to the current state that they are in (locked, vented, etc)

TITLE: 01/21 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: 5mph Gusts, 3mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.17 μm/s 
QUICK SUMMARY:

Some of the tasks on the board today:

• More HAM7 work, in laser hazard
• HAM1 viewport simulator
• Laser vibrometer measurements of MCT baffles

We have intalled the POP periscope stiffener.

Some dog clamps in the REFL path as well as the cable bracket for PM1 were relocated to accomodate. 1st and 2nd picture are "before" photo. 3rd one is after PM1 cable bracket relocation but before installing the stiffener.  There are also three "after" photos showing how things look on the table.

POP beam clearance:

I took the picture of the bottom periscope mirror through dichroic (HR for IR, transmission for green) to see the beam clearance. In the first such photo (POP_beam_clearance.jpg), the camera is close to the center of the dichroic and the short stiffener beam is close to the edge of the optic but not occulting the mirror, so we're OK. Just to make sure that we're absolutely safe, I moved the camera closer to the -Y edge (right on the picture) of the dichroic (POP_beam_clearance_extreme.jpg) and it still looks OK.

If it's hard to understand what was done, look at the annotated photo (the last attachment After_stiffener_installed_annotated.jpg), the cellphone camera was inserted to "Camera" position.

REFL beam path:

I confirmed that the long stiffener beam doesn't interfere with the motion of the REFL beam diverter. Also, when the REFL beam diverter is open, I looked into the last steering mirror for the REFL air path from the viewport position to make sure that the short stiffener beam won't occult the REFL path. 

Some hiccups:

We used D2500433 -11 variant S/N 4 and -1 variant S/N1 even though page 11 of T2500339 suggests it should be -10 and -2 variant, respectively.　We didn't have -10 variant, and -2 variant was absolutely too short.

B&K

We performed B&K hammer measurements before/after the stiffener installation for POP periscope. Before, there was a 70Hz-ish peak. After, it was pushed higher up in frequency. The transducer was attached to the ISI table and Jim hammered the top of the periscope.

Likewise we did B&K test for the input periscope of the JAC even though it was not absolutely necessary.

We haven't done B&K for the JAC output periscope because it's not even fully clamped down (we will move it).

Jim will post the data.

[Sheila, Karmeng]

FC1 alignment was adjusted to account for the buoyancy, and we coaligned the FC1 green/IR beam. We managed to recover the FC refl green on SQZT7 periscope, but not on the photodiode.

The OPO IR transmission is misaligned, and we managed to recover the IR on SQZT7 PD. As we recovered the IR refl (top) on SQZT7, we saw an improvement from ~600 to ~1680 (we may have been clipping on the refl PD previously).

By changing the setting on ZM2, we managed to improve the IR trans (bottom).

Old setting ZM2 PIT: 424 ; YAW: -235

New setting ZM2 PIT: 444 ; YAW: -315

Will need to check on the iris tomorrow, to make sure we did not deviate from the original path.

Sheila, Karmeng, Rahul

This morning we physically moved ZM4 (since the sliders were saturating the DAQ output) in YAW to better align it with ZM5 and ZM6. More details (including health check results) will be posted later.

ZM4 is now dogged down to its new position.