Addressed TCS Chillers (Tues [Jul21] 919-934am local time) & CLOSED FAMIS #64385.

For measurements below, measuring from "top" of the red floaty ball.

• TCSx Chiller:  Had level of 29.5 cm.  Added 250mL for 30.6cm.
• TCSy Chiller:  Had level of 10.3 cm.  Added 110mL for 10.5cm.  
• There was no water in the small cup under the slow leak.

Ryan S, Camilla 

We put the nanoscan profiler downstream of ZM2 (between ZM2 and ZM3) in 6 different locations. We used a steering mirror to get the two locations closest to ZM2.

At each location we took data:

• At three different ZM2 PSAMS settings near our nominal (2.65V, nominal 3.15V, 3.65V)
  • so that we can later understand what ZM2 ROC is needed for best FC mode matching
• At two different beam spot heights on ZM2, old (5.85" high) and new (5.75" high)
  • As we expect new to be better as the designed beam height is 5.5" at ZM2 but we cannot reach this without mechanically offloading ZM2 90946.

Data is attached, we also have photos of all data. The photos of each location are attached. 

TITLE: 07/21 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 2mph Gusts, 0mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.09 μm/s 
QUICK SUMMARY: Commissioning of the JAC and more IMC/corner locking work planned for today along with continued leak checking of the vacuum volumes. Looks like the IMC is staying locked nicely with it only dropping out a few times overnight, where most of these correspond wiht JAC unlocking as well.

• Wind and other ground motion low
• Dust counts acceptable
• CDS overview green except for known DAQ-KC0 disconnects
• All other systems nominal

Work stations were updated and rebooted.  This was an os packages update.  Conda packages were not updated.

(Travis, Jordan, Gerardo)

We are using the same setup as before, see here, leak detector attached to the MTP on the XBM.  Today's helium background reported by the leak detector was 2.0x10^-10 torr*l/sec.

List of items that we have leak checked is below, if crossed no signal detected above the background.

Input manifold:
VP5 (+X side)
VP7 (-X side)

Output manifold:
VP5 (-Y side)
VP7 (+Y side)

Filter cavity tube section B:
Bellows flange connecting to FCB1.

X-manifold
A-1C VP4
A-1C VP5
The 8" port on the X-manifold that was blanked off. 

Y-manifold
A-1F VP2
A-1F VP3

HAM5:
A1F2
Viewport, adapter, and components, jig for getting beam from HAM5 to HAM7.

BSC2:
G11
4.5" blank on dome gauge tree adapter.  Was gappy, so new gasket installed and re-torqued.

HAM2:
A2F1
A2F2
A2F4
A1F1 <-- signal detected at 4.7x10^-10 torr*l/sec, we may replace the seal on the next vent.

HAM3:
D4
This flange is divided into 3  4.5" CF ports, two of the 4.5" are fiber ports, both of them were tested and no leak was detected above the background (D4-1J1 and D4-2J1). 
On the last 4.5" port there is a 5WX, and on the first conflat that we tested there is a noticeable gap on the gasket joint, see photo.  A leak was detected, and the signal peaked to 1.2x10-09 torr*l/sec, we may replace the seal on the next vent.
We still have other flanges to test on this cross, and the rest of the chamber, but once again the background on the LD saturated due to the leak, we will continue leak checking once the background drops to acceptable numbers.

Other items left to check:
HAM3:
D4 The rest of the flanges on the cross.
A1F3
A1F4
D3
D2
D6

HAM7 and relay tube will be checked later, once the chamber is closed and pumped down.

IMC Fast path looks good.

I and Elenna went to the floor and measured the OLTF of the IMC loop, injecting into the IMC CM board. UGF was 43.2kHz with 54deg phase margin, a bit high in frequency but not crazy high, and the TF shape was good in amplitude as well as phase. See PXL_20260720_192425851MP.jpg.

FYI the UGF was 38.5kHz back in March 09 2026 (alog 89438).

M3 stage acquire ON/OFF switching question.

We have noticed that the TF from M3 coil input (or drvalign_L2L_OUT) to VOLTMON and FASTIMON changes as Acqire ON/OFF changes. Is this supposed to be the case? And none of these TFs are flat. Is this supposed to be the case?

MC2-MC3-M3_BIO_TF.png shows the TF from M3 DRIVEALIGN_L2L_OUT to FASTIMON for MC2 and MC3 in various BIO states.  State 1 (Acq Off, LP Off) and state 3 (Acq Off, LP On, this is our nominal state) give the same TF, which is different from state 2 (Acq On, LP Off) and state 4 (Acq On, LP On).  We can say that LP On/Off is properly compensated for in digital but I'm not sure if this means that Acq On/Off is not switching in analog, because I don't know how the IMON in implemented.

Caveats: For MC2 all four states were tested. For MC3 only state 2 and 3 were measured. MC2 and MC3 are consistent with each other. TFs are only plotted for LL because all coils look similar.

FYI, on Friday we have tested to acquire in all four of M3 BIO states and never successfully locked IMC with nominal M3 gain for any state. Even if acquire ON/OFF is stuck to one state in analog (which I'm not sure if that's the case), it's not the only problem.

Today I tested locking with state 2, it didn't lock with nominal gain but it locked with the same reduced gain setting we've been using since Friday (ISCINF_L_GAIN=0.035, DRIVEALIGN_L2L_GAIN=0.2). I switched the state back to state 3 after that.

M3 stage comparison with MC1 and MC3

Screenshot_2026-07-20_11-51-08.png shows the M3 stage DRIVEALIGN_L2L_OUT to M3 witness L transfer function for MC1, MC2 and MC3 from left to right. They all look different but MC2 shows an extra bump at 3Hz.

Other observations

IMC sometimes locks without M3 stage feedback, but fails much more often than with M3 stage feedback, seemingly due to larger kick to the FSS.

Once IMC locks, you can easily switch between the following gains. Both seem to be very stable:

I never successfully transitioned to "all full" actuation (i.e. M3 DRIVEALIGN_L2L_GAIN=1 and M3 ISCINF_L_GAIN=1) nor M3 reduced by 0.2 and M1 M2 full (i.e. M3 DRIVEALIGN_L2L_GAIN=0.2 and M3 ISCINF_L_GAIN=1). 

TITLE: 07/21 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: LVEA is LASER HAZARD. The dust alarms keep going off for the optics lab since there's so much stuff in the air despite the low wind.

Still some confusion regarding MC2's M3 BIOs. I went into the CER and tried turning the BIO chassis for MC2 off and back on (SUS-C1 U17 and U18). Checked plugs to chassis and to BIO cards. Tightened a couple screws but plugs didn't seem to be loose. Don't think tha would've done anything, but we'll keep looking at it tomorrow.

LOG:                                                                                 

The first image is sdf diffs created after we phased the JAC WFS readouts this morning, the next two are cdsFilt banks that have no filters and a gain 1 but need to be on to route signals from the wavefront sensor readout matrixes I_mtrx and Q_mtrx to the normalised channels H1:JAC-WFS_A_I_PIT_NORM, H1:JAC-WFS_A_I_YAW_NORM, H1:JAC-WFS_B_I_PIT_NORM, H1:JAC-WFS_B_I_YAW_NORM. Confusingly, these are not displayed on the standard 'JAC_WFS_Settings' screens so I might have to put them on there so this doesn't happen in future (this is probably some legacy infrastructure I copied over from the IMC_WFS model blocks that we don't really need).

Took some health check transfer functions for the BBSS in vacuum for the first time. I took a set with damping ON and then a set with damping OFF. These measurements were taken in HEALTH_CHECK, but with the opticalign sliders back on and damping settings appropriate for the measurement type. There was no difference in the measurements when the offsets were on vs off so I just left them on.

In-Chamber in-air vs in-vacuum with Damping OFF vs ON comparison:
/ligo/svncommon/SusSVN/sus/trunk/BBSS/Common/Results/allbbss_20260720_BBSS_InVac_DampingONvsOFF/allbbsss_20260720_BBSS_InVac_DampingONvsOFF_ALL_TFs.pdf
r13071

DAMP OFF

Matches with the last measurement we took in-air on July 6th (90925).

Settings
- BS in HEALTH_CHECK but with:
    - OPTICALIGN OFFSETS ON (they don't make a difference with these TFs)
- HEPI and ISI are in their nominal ISOLATED states (ISI no ST2 boost)

Data
/ligo/svncommon/SusSVN/sus/trunk/BBSS/H1/BS/SAGM1/Data/2026-07-20_2100_tfs/2026-07-20_2100_H1SUSBS_M1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml
r13070
Results
/ligo/svncommon/SusSVN/sus/trunk/BBSS/H1/BS/SAGM1/Results/2026-07-20_2100_tfs/2026-07-20_2100_H1SUSBS_M1_ALL_TFs.pdf
r13070

DAMP ON

Damping is working pretty well for most peaks, but there are a few peaks that end up shifting quite a bit - most noteably the highest Pitch peak shifts from 2.1 Hz to 2.6 Hz.

Settings
- BS in HEALTH_CHECK but with:
    - DAMP ON
    - OPTICALIGN OFFSETS ON (although they don't make a difference with these TFs)
- HEPI and ISI are in their nominal ISOLATED states (ISI no ST2 boost)

Data
/ligo/svncommon/SusSVN/sus/trunk/BBSS/H1/BS/SAGM1/Data/2026-07-20_1800_tfs/2026-07-20_1800_H1SUSBS_M1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml
r13068
Results
/ligo/svncommon/SusSVN/sus/trunk/BBSS/H1/BS/SAGM1/Results/2026-07-20_1800_tfs/2026-07-20_1800_H1SUSBS_M1_ALL_TFs.pdf
r13069

TITLE: 07/20 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: Oli
SHIFT SUMMARY:
HAM8 was SEI was taken to ISI Damped HEPI Offline and the SUS was taken to SAFE for a DAQ restart today at 19:39 UTC. 

ZM5 taken to safe due to PSAM Issues. ~SUS team 

Vacuum is now pumping down again. BSC2 is near 1.8 e-6 torr and falling.   

LOG:                                                                                                                          

Sheila, Keita

I went to ISCT1 and Keita aligned PRM.  We saw the beam on the periscope, it was making it to the camera.  The camera normally gets the transmission through an HR steering mirror pointed at REFLAIR B, this was moved out of the way during in chamber work so the camera could be used.  When I put this back in it deflects the beam, so it is no longer on the camera.  I think we need two people to realign this camera. 

I aligned REFLAIR A + B.  REFLAIR A has two ND filters on it that make it easy to align some kind of glint to the diode.  

In O4, in the guardian state 101 which is DRMI locking (2W input, PRM aligned), REFLAIR B had 6 counts DC, REFL AIR A was about 2 counts.  Now REFLAIR A is 1.8 counts, but REFLAIR B is 3.6 counts.  So we should revisit the alignment of REFLAIR B.  

Fil, Daniel, Rahul

To further investigate on what is causing issues with ZM5 PSAMS (as reported in LHO alog 91120) I did a chamber side test (as per E2100371-v1) on the SQZ racks near HAM7 chamber. This time I was not able to drive the PZT voltage, which typically should vary from 0-200V. In this case it was showing -7V.

Next I connected ZM4 to ZM5 chassis to test the electronics chain - ZM4 PZT and SG voltage read fine. Next, I connected ZM5 to ZM4 electronics - again no PZT voltage. Hence, this ruled out any issue with ZM5 chassis and the issue seemed to be upstream of it (i.e. pointing towards the cables or in chamber).

To test the cables, at first Fil and I measured the impedence and capacitance of the PZT on both ZM4 and ZM5, as listed below,

ZM4 (PZT)- capacitance (pin 1,14 on db25)  =20.9 micro farad, Impedence = in mega ohms.

ZM5 (PZT) - capacitance (pin 1,14 on db25) = open circuit, Impedence = 2360 ohms  - which shows electrical shorting somewhere).

We unplugged the in air cable and in vacuum cable of ZM5 and the resistance was high - thus showing no shorting at the cables downstream of PSAMS. 

Hence, the PZT inside the PSAMS is shorting. 

Today I added the ADC connections to the HAM2 ISI model for the St0 L4Cs that we added in that chamber during the vent. To connect these sensors we are adding a D1500490 L4C interface chassis into the SEI-C2 rack. The output of this chassis is 3x db9 connectors that carry the seismometer and pressure channels. The last 2 db9 connectors are free on each of the HAM2 AA chassis, but Dave reminded me that Ch 32 (or 31 depending on your math) carries the duotone signal. So the corner 1 L4Cs are on ADC0 ch 24-27, corner 2 on ADC1 ch 24-27 and corner 3 L4Cs are on ADC1 ch 28-31. We still have ADC0 ch 28-30 free if someone wants to plug something in. Fil is working on getting ready to add the chassis to the rack and cable everything up. After that, I don't think I will be ready to commission the feedforward until after I can unlock HEPI.

This model change will go in when we restart HAM2&3 tomorrow morning.

A measurement of the HAM3-ISI motion was taken over the weekend [1] to compare the performance of this ISI now vs last year, following the replacement of the vertical CPS (ECR E2200301)

Thanks to the lower noise of the vertical CPS (90911), we see an improvement in the tilt dofs (p1 and 2 of the attached pdf) where the CPS noise was previously limiting. For Rx this is from 0.1Hz and above, and for Ry this is from 1Hz and above - up to a factor of 6 reduction, near 0.4Hz and 1Hz. For reference the noise budget shown on p7 of G2100779 shows the CPS noise limitation of the HAMs with the previous set of CPS.

It is interesting that Rx and Ry have different tilt amplitude between 0.1-1Hz (Ry is higher) and may indicate some noise injection from other loops. With the CRS now on the table, this will be easier to address.

Those improvements will contribute to a lower suspension point motion of MC2 and PR2. We will add those spectra to this alog once we gather the data.

[1] Status of the ISI for this test : 

• SC was turned on 
• Blend filters were set as shown on the screenshot attached
• The input motion is comparable between the two dates (see hepi data) - except at the microseism which is higher in the before / reference, but not relevant for this test.

As was reported before (91114) the JAC/HAM1 temperature has been drifting up and it's still changing. See the first attachment for the 8 days trend.

As the things heat up, the PZT has to compensate and hit the rail eventually, unlocking JAC. The second attachment shows that the JAC is unlocked repeatedly, most of the lock stretches chopped up to 30 to 40miniutes. See the top right that shows the JAC PZT voltage. If JAC happens to lock to the fringe at higher voltage the lock lasts longer, but the lock duration is limited by the temperature drift.

The temperature is leveling off slowly, and the last lock lasted for 4.5 hours.

But we need a temperature loop. Maybe we can start with maximum heat (right now we're pumping out 3W nominal into 25 Ohm but Daniel says the driver can handle +-18V 1A, so up to 13W seems to be possible), wait for half day or so until the effect of that mostly levels off, turn the servo on and see how far we can go.