Jenne, Wanda V, Gizem K

Wanda and Gizem arrived today to help set up the DAS (distributed acoustic sensing) system that we're going to test for a few months.  We're borrowing DAS interregators from EarthScope, and using spare dark fibers that go down the arms.  The DAS will measure strain changes in the fibers.  We've got 2 models of DAS interregator on site, however only commissioned one today.  Both models are eye-safe, and have been registered with the LHO LSO.  

Since we need to connect to the fibers that are buried along the inside of the arms, the interregators are set up in the MSR close to the fiber junction box. 

Fil did the actual connection to the LIGO fiber box, connecting some short 10m fibers that Wanda brought.  We're using fiber #24 on Xarm (the fiber junction box calls this Right) and fiber #24 on the Yarm (the junction box calls this Left).  Gizem took OTDR (optical time delay reflectrometry) measurements of each of our 4km fibers (one on the Xarm, one on the Yarm).  The reports are attached here.  One of the connectors (likely at the junction box) on one of the arms is a little lossy (0.6 dB loss), but since it's the junction box we're just going to live with it. Also, one of the splices at the midstation is better than the other (I think it's the Yarm that is better).  More details are in the attached pdfs from the OTDR measurements.

We elected to just use rack 120V, rather than the UPS 120V, since we don't have long enough UPS-specific power cables.  The power here on site is plenty good quality for the DAS.  

We watched the data live on the monitor that is set up with the interregator in the MSR, and indeed it's working!  We're going to leave it running overnight and have a look tomorrow at the data, particularly to see the quiet time in the middle of the night.  

The attached photo is of the setup we've got on the far side of the MSR.  The black case is the Febus DAS interregator, and we've got a 21 TB hard drive attached to collect the data. The fibers go up in the overhead tray, then down to the junction boxes which are at the very top of that first rack. 

Tomorrow we will start work on the following to-do items:

• Connect one of the arms instead to the other model of DAS interregator (should be very quick), to see if there's a difference.
• Work with Nyath to set up remote access via the GC network to the DAS' internal computer.  Wanda and Gizem will find from their IT folks what their IP address ranges are, and then we'll only allow access from those IP access ranges.  
• Walk the first few hundred meters of each end of the fibers (from the corner, and from the end), and do a 'tap test' from known locations to see where in the fiber length those show up.  We've got a work permit in and have talked to both Mike and Richard about outdoor hazards (heat, animals, etc).  Once that's signed we'll go for a walk in the morning, probably bringing a sledgehammer with us for ground 'tapping'. 
• Go to each end station, to have a look at the other end of the fibers.  We will likely ask Fil to connect a jumper cable to the end of the cable in the end station, and then will put a terminator or something on the end to reduce the losses there. 

Elenna, Oli

We spent some time figuring out SDFs for the BBSS. It should be all good to go.

A couple of notable channels that will need to be figured out at some point are:

• H1:SUS-BS_M2_DRIVEALIGN_Y2L_GAIN: For the BSFM this gain was set to 11. Since we had inputs coming in for this filter we decided to commit it as a gain of 0 until we verify the gain that needs to be there
• H1:SUS-BS_M2_OLDAMP_{P,Y}_GAIN: For the BSFM the P gain had been set to 300 and the  gain had been set to 650. We seemed to be doing okay with that value, but something must've changed while we were consolidating SDFs that made it so we started saturating the M2 DAC. So we turned both these gains to 0 and will need to figure them out.

I've attached a pdf with the full list of sdf diffs that we accepted. The notable channels listed above are highlighted as * and **

WP 13455 and prep for 13457.

Dave has been labeling machines and adnico cards.  This will help us put fibers back in the right place after we disconnect them as part of the upgrades tomorrow.

I added the new IPC switches to the DNS today.  The switches are staged in their respective buildings with all the optics.  Their config has been updated to use the production logging, network time, and to allow polling from our network management host.

We got all the ethernet cards with the proper 1/2 height adapter and added the required optic.

We brought in a W3323 systems from the test stand and staged it in the MSR this will become the new h1seih23, as we need to have another core available for the ethernet IPC.  I updated the BMC address so that it can be remotely administered on the production network.

Dave has been to the end stations with Tony to stage equipment and help finalize layouts and plans.

We had a plan review meeting this afternoon. 

Dave will probably add some more notes tonight after checking on the SDF status, filter status, and model build status.

Looking at SDFs, on Feb 20th of this year the IMC input offset was changed from -0.38 to -0.07, but not SDF'd.  I don't find anything in the alog from that date that would indicate this was an intentional change.  For now I will revert the change, but we can keep this in mind, or perhaps change it back if someone remembers doing this intentionally.

Ryan C, Rahul

In preparation for our second replacement of the PSAMS, we have taken SUS ZM5 out of HAM7 chamber and staged it on the table next to it. We took the bottom stage PSAMS out of the suspension cage - this unit has wires shorting inside the mirror housing.

Tomorrow morning we will start replacing it with the unit CIT has shipped us - which was originally installed in ZM5 (LHO) but broke down two weeks ago (Strain Gauge wire leads got loose inside), then got fixed at CIT and re-shipped to us with 65 in-lb torque.

Today I went to check the SDF diffs in the ASC model, and noticed some of the anti-whitening settings were different for ASC-POP_A, ASC-POP_B and ASC-AS_C. Tony directed me to a time when he had checked and ensured the anti-whitening settings matched the whitening settings for all diodes.

However, Keita had changed the settings on those three diodes in this alog, just for BBSS alignment purposes during the vent: 90656.

I adjusted the whitening/anti-whitening settings on the three diodes to be back to the usual settings, which cleared SDF differences.

I also changed a ASC-POP_X NSUM normalization value, which was an arbitrary number from a long time ago when the diode was an air diode, but is likely no longer correct now that it is in-vac. This means that if you trend ASC-POP_X_DC_NSUM, you will see a large  change in this diode around this time, due to the fact that we are no longer normalizing by 407.

The remaining ASC SDF diffs are due to the guardian or temporary commissioner changes we do not need to save.

Betsy recommended confirming the status of PR2's M2 and M3 transfer functions to make sure there isn't also a mistake with their feedthrough cabling, and I can confirm that PR2 is cabled up correctly.

I had checked PR2 M2 to M2 and M3 to M3 last week while troubleshooting MC2 but they had bad coherence so I just retook them with better coherence to double check and they look llike they should.

Data
M2: /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/PR2/SAGM2/Data/2026-07-27_2050_H1SUSPR2_M2_WhiteNoise_L_0p02to50Hz.xml
M3: /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/PR2/SAGM3/Data/2026-07-27_2100_H1SUSPR2_M3_WhiteNoise_L_0p02to50Hz.xml
r13085
 

Camilla, Rahul

SUS ZM2 in HAM7 chamber needed a pitch offload since it was using up a lot of DAC output. This morning we went to HAM7 chamber and at first confirmed the beam alignment and its position on the irises. Then I entered in HAM7 chamber and locked the suspension and unlocked the pitch adjuster screw. At first I gave it a full 1 turn anti-clockwise making ZM2 pitch down (and then unlocked the suspension) and Camilla confirmed that the alignment looked better but perhaps we overshot by a small amount. I retracted by 1/4 turn (thus making 3/4 turn anti-clockwise in total) and then the beam looked good on the iris. Before exiting the chamber I locked the screw for pitch adjuster and checked if all EQ stops were set free from the suspension chain.

Finally Camilla adjusted the alignment sliders on ZM2 for fine tuning it. 

I took a quick chamber side transfer function measurements and the suspension was found to be healthy.

Took ZM4,5,6 to SAFE. 

Accepted some TCS HWS settings, turned the EY enclosure lights off via medm (already off on table) , unmonitored the CHETA flipper. Attached.

Stil have more SQZ and CO2 to do....

TITLE: 07/27 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: CALM
    Wind: 3mph Gusts, 0mph 3min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.09 μm/s 
QUICK SUMMARY:

Quick scan for the week looks like HAM7 may get closed up this week, CDS has a list of items, Y-Beam Manifold's GV work, cleanroom moves.

IMC guardian is set to DOWN (ISC lock is in MANUAL & at IDLE.

As a test, HAM3 Ry loop was switched to SUPERSENS6 blend, which includes a newly designed 30mHz CRS blend. It has been running stably for the last 20 minutes.

start_gps = 1468138518

note - to avoid confusing results I also turned off the CPS-DIFF loop

Jennie Wright, Khanh Vu

This morning, we entered the calculated values into the sensing matrices on the JAC menu. We encountered a few points of confusion that are worth mentioning:

1. The calculated matrix contains 16 values because it is a 4x4 matrix, with four possible angular actuator offsets and pitch and yaw readout channels from two wavefront sensors. However, the matrices on the JAC panel contain only eight inputs. This design assumes that, ideally, a yaw actuation produces only a yaw signal and a pitch actuation produces only a pitch signal. In practice, the system is not perfectly decoupled, so we observe cross-coupling between pitch and yaw, leaving us with more than eight matrix entries.

2. For the PZT actuator, the relationship between pitch and yaw is reversed. A pitch offset produces a signal in the yaw channel, while a yaw offset produces a signal in the pitch channel. This is due to the configuration of the optical components, and this convention has been maintained in the control system.

We will continue working on the sensing matrix on Monday to determine how to account for these issues.

We been commissioning the CRS this week, so far we've done a tilt to tilt measurement:

• We excited RY on HAM3 for about 40 minutes starting around 1468604538 (2026/07/20/17:42:00). The excitation template is located at /ligo/svncommon/SeiSVN/seismic/HAM-ISI/H1/HAM3/CRS/Templates/dtt/ryex2.txt, and we ended up finding that setting the gain to ~2000 works well. 
• The dtt template used is CRS_tilt_TF_072026.xml and is located in /ligo/svncommon/SeiSVN/seismic/HAM-ISI/H1/HAM3/CRS/Templates/dtt/CRS_tilt_TF_072026.xml 
• Because the excitation window was so short (~40 minutes), we can only get 2 averages, and I've attached a picture of the result of the measurement (picture 1). We used these measurements to calculate parameters of the response function using a Matlab script which fits the data gotten from the excitation.
• The script used to get these parameters are in /ligo/svncommon/SeiSVN/seismic/HAM-ISI/H1/HAM3/CRS/Scripts/CRS_TransferFunction.m
• To run the script, we got a Q measurement for the CRS in vacuum using /ligo/svncommon/SeiSVN/seismic/HAM-ISI/H1/HAM3/CRS/Scripts/ring_down.m and looked at a 12 hour period starting at 1468630128, which gave a Q measurement of 4365.
• Using the parameters from CRS_TransferFunction.m, we got the zeros and poles of the CRS response and used those to make a new SensInv filter (SensInv_Meas) for the CRS (H1ISI_HAM3_CRSRY_THETA, located in the THETA block of the CRS_OVERVIEW). We used a Q of 50 for the zpk to determine ring down times. 

Summary:

• In vacuum Q of 4365 (picture 2)
• Parameters: delta = 1.04e-5m, w0 = 0.0222Hz, wR/(2pi) = 0.0253Hz (which is what we expect), wg=0.0764
• Found response from both fitting the data and from zpk parameters (picture 3)
• Created new inverted response filter called SensInv_Meas (ring down plot in picture 4)
• Looking at the in air (1467529134) vs in vacuum (1468744818) performance (picture 5, with in air being green), the noise has decreased significantly
  • On a slightly related note, it seems like there is an issue with dtt displaying the spectrum at higher (>1Hz) frequencies. When plotting the same channels at the same time, and applying the response inversion filter offline in Matlab, the post inversion signal (THETA_OUT) doesn't flatten out and follows the input (THETA_IN1) (picture 6)
  • Arnaud also found that adjusting the windowing settings in dtt gives a better measurement (see SEI alog 2582) I've applied the change to the most recent CRS template.