Daniel, Erik, Jonathan, Dave:

At 12:39 we restarted the DAQ and the EDC to included a new H1EPICS_ECATISCCS.ini. This adds 43 new JAC-HEATER_CONTROL channels.

No issues with this restart.

[Jim W., Shoshana A., Michael R., Huyen P.]

0. Since HAM3 ISI has been updated with new CPS sensors (with fine vertical CPS), Jim updated new symetrization filters for the actuators using the ISI commissioning scripts.

1. We have been testing CRS in/out of loop looking at IMC length (mostly during night time with IMC locked at 2W). The wind condition has been relatively quite so far for these tests. We can repeat in higher wind (ground tilt) condition.

    We will try lower blend, e.g. 45mHz.

2. With CRS out of loop, we compared tilt spectra for CPS, GS13, and CRS. Without the proper capacitive damping, the OFFLINE/DAMPED stage rings up the CRS, making low frequency signal worse. Under ISOLATED state, the CRS can be damped, and CRS matches GS13 between 0.2Hz - 1 Hz. This test has been done at MIT, see alog 12136.

3. I also did make a different set of GS13 vertical symmetrization filters using global Z comb drive scripts from Brian, see last figure. The filter file is living under /ligo/svncommon/SeiSVN/seismic/Common/Documents/T2300404_HAM_symmetrization/ham3_fine_cps_and_crs/. We will test this later.

The new RCG separates the ADC and DAC overflow counters (previous RCGs combined them into a single counter). I have modifed the CDS Overview to show any model whose DAC counters are overflowing (counter > 0). This is shown as a purple square in the 6th block.  I have also added an overflow counter reset button in the lower right corner, called "OVRFLO RST", which issues an overflow reset on all models. Note that the overflow reset button resets both the ADC and the DAC counters.

Two models have continuous DAC overflows: h1tcscs and h1alsex. These are DC drives of 16bit-DAC channels

h1alsex

is driving its DAC ch8 (H1:ALS-X_WFS_AUTOC_PZT1_PIT_MON) with a dc signal of 35000, which exceeds the 16bit-DAC max value of 32768 before any upsampling.

h1tcscs

is driving its first 3 DAC chans each with a signal of 32768, which exceeds the operational range.

and is driving its DAC ch12 with a dc signal of 28521, which looks like it is in range, but after upsampling with zero-padding, produces an AC signal which spikes above 32k 2048 times per second.

We are investigating if we could change h1tcscs to no use zero-padding for its DAC. The main risks are with any non-DC drives, and possible recalibration for DC drives when they become actual DC signals.

Jennie W, Sina K, Jim W,

Yesterday we continued the checking we have been doing of the digital signal chain in CDS. We found that a lot of channels appear to be zero due to the decimation filters used on OUT16 channels and also that these were set to round the displayed channel to 1 significant figure. We corrected most of these on the main screen but I still have to go through the subsidiary screens and cross-check that we got all of these. Here are the new digital LO readout channels we introduced the other day (alog #91504) and here are the changes we made to monitored channel yesterday.

In the process we checked the calculation of the magnitude and phase of the reference and measurement interferometers (this is displayed in the 'monitor' block on the main SPI overview screen). The phase seems ok and indeed the 'phase unwrap' button that can be pressed to reset the phase of the IFO to zero after it accumulates more that 2pi of phase, seems to work well. We checked all the filtering done on the demodulated signals and those seem ok too.

Once we had checked all the signal routing we got signals out for the efficiency calculation. These seemed very low (~25%). After checking the raw PD into CDS against the calculated mean and peak to peak ampltiude of the beat signals which are used to calculate the efficiency, we realised that the efficiency should be above 80% but there is something wrong with the calculation of the peak to peak amplitude. To fix this we will try removing the phase rotator block in the interferometer simulink model as we think these blocks are unnecessary and might be doing something unexpected.

We also double checked the signal processing of the QPD channels and confirmed that these still need calibrated into radians of ISI motion. Per Jim's suggestion we will use the ISI sensors to calibrate these.

Summary: Most parts of SPI medm and model checked - still need to debug demodulation of signals for heterodyne interferometer.

Sheila, RyanC

I ran the full (all 6 dof) undamped TFs and the OLG templates for P and Y for PR2. For P and Y the magnitude of the TF was off. On the OLG for Y the magnitude is low, and we're not fully sure why. We doubled the gain of the P and Y damping loops from -0.5 to -1.0, this reduced the oscillation seen when moving sliders by ~half, see before and after... Also noting that PR2_Y sees the oscillation both in M3 and M1 whereas PR2_P only really sees it in M3. This is likely not the final solution but it helps for now.
I have accepted these two gain changes in the PR2 SDF safe file.

Miranda, Dave:

Over the past week we have documented the LHO PEM accelerometers and produced an as-built  wiring drawing

This was in response to a possible misreading of accelerometer(s) with the wrong channel names.

We found three accelerometers with incorrect names, which date back to pre-O4, so I'm tagging DETCHAR.

We fixed this at 16:00 Thursday 13th August 2026 PDT by remapping the BNC connections on the front panel of APC1. The cable going to port12 was moved to port13, that going to port13 was moved to port14 and that going to port14 was moved to port12.

We tap-tested the EBAY_FLOOR accelerometer at 16:10 and this showed up on H1:PEM-CS_ACC_EBAY_FLOOR_Z_DQ

We installed Jennie's new h1spih23 model (removed parts) which required a DAQ restart. Model was restarted at 08:02 and the DAQ restart between 08:04 and 08:20.

TITLE: 08/14 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: 8mph Gusts, 6mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.12 μm/s 
QUICK SUMMARY:

• HAM7 doors are on as of yesterday
• The air quality is decent this morning, aqi of 45
• Temps, dust are goods
• H1LSC has a floating point error
• Sheila's testing some MICH asc loops

(Randy, Travis, Gerardo)
Today we installed two doors on HAM7, -Y door and +X door (flat door). Nothing to report with respect to the installation since no issues were encountered during the process. Both doors were torqued.  Currently the annulus system is being pumped down with an aux-cart and a small can turbo, at end of the day the pressure at the aux-cart was reading 8.8X10^-05 Torr. A very "wet" system and it shows on the pumpdown.

A side note for future +X door installation, use a bigger shackle on the -Y pick point, since the door needs a little rotation. 

The JAC WFS DC signals were calibrated. The motivation for this measurement is to check that the optical layout model is right. With JAC unlocked the beam in reflection is close to a pure TEM₀₀, and the DC quadrant signals calibrate easily by normalising with the beam size. That makes the unlocked DC a clean sanity check on the layout and on the calculation built from it.

What was done

1. Unlock JAC.
2. Centre the WFS A and WFS B DC signals using the picomotors.
3. Two independent excitations:
   • (i) calibration lines. Four lines, one on each actuator (JM1 PIT 9.7 Hz, JM1 YAW 11.3 Hz, PZT PIT 13.1 Hz, PZT YAW 14.9 Hz), driven simultaneously; the peak height was read out at each WFS DC.
   • (ii) broadband. White noise below 10 Hz injected into one actuator at a time, and the transfer function to each WFS DC measured.

What is predicted

The TEM₁₀/TEM₀₁ that each actuator generates is known in magnitude and phase from the actuator calibration and the layout model. At the WFS, these have rotated away from TEM₀₀ by the accumulated Gouy phase between the actuator and the sensor. A DC quadrant photodiode reads the real part of the first-order mode amplitude at its own plane (more precisely, the real part of the odd modes), so the accumulated Gouy phase over that path fixes what the WFS DC signal should be. Nothing else is needed: the magnitude follows from the beam radius at the actuator, the phase from the accumulated Gouy phase.

Results

The direction is the angle of the (WFS A, WFS B) response vector, and the magnitude is its length in units of normalised beam displacement per drive count. Three of the four lines agree with the prediction to within 5 deg in direction, and the magnitudes agree to within 8% (max/min 1.183 across the four, std(log) 0.064). 

The two excitation methods agree with each other: comparing the sensor-basis direction obtained from the calibration lines against the one obtained from the broadband injection gives +6.79, +5.56, -0.24 and +0.19 deg for PZT PIT, PZT YAW, JM1 PIT and JM1 YAW. 

JM1 YAW is the exception, off by +24.68 deg. Why this one line alone fails to be predicted is not yet understood. Several explanations were tried and none survived: moving JM1 along the beam would need 29 cm; moving WFS B by 2.5 cm removes the JM1 YAW discrepancy but drives JM1 PIT from -4.9 to -30 deg; the astigmatism degeneracy in the layout fit spans 2.1 deg against the 14.3 deg required; the ghost beam is ruled out because the result is unchanged across the ghost dump (we did same measurement before the ghost beam dump campaing); and the yaw to length coupling of the suspension would need to be of order 10 um for against the 0.003 um the JM1 OSEMs seee. 

TITLE: 08/14 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

IFO is in IDLE with the IMC Locked

Good progress today with locking DRMI, which is now consistently locking for a few minutes - alog 91530

LOG:

[Sheila, Ryan, Masayuki]

We got DRMI to lock for several minutes. By the end of the session it was re-locking every one to two minutes, though each stretch of lock lasted less than five minutes. 

After locking PRMI and aligning the BS and the PRM, we requested ACQUIRE_DRMI_1F and tried several combinations of the PRCL/SRCL/MICH gains. Eventually we found the combination which can grab the DRMI lock, and that was the original gains except for PRCL. The PRCL gain had been doubled yesterday (input matrix 1.75 -> 3); we reduced it to 2.5, and with that we could lock several times.

In the short stretches of lock we measured the OLG of each loop. PRCL and MICH both have a strange phase rotation around 10 Hz. The MICH loop gain was also on the low side, so I increased it and tried to lock again.

While waiting for the next lock in that configuration, I moved the SRM more or less at random by ~20 urad in pitch and yaw, and found that the better alignment made POP90 more stable (see attached plot). In that stretch I re-measured the MICH OLG, and its UGF was close to what we had for PRMI. So this looks more like an alignment issue than a loop gain or loop shape issue.

I then found that the MICH loop gain was by now too high to engage the boost (FM1 of MICH1), so I halved it. With that gain the guardian could engage all the filters in the DRMI_LOCKED state.

I measured the SRCL gain again and it came out lower than in our first measurement, though I am not sure that measurement is valid. I tried a higher SRCL gain and it seemed unstable, but that may have been the alignment degrading rather than the gain itself.

I stopped here. The guardian is left in the configuration that felt like it gave the most frequent locks.

The attached TFs are the first MICH/PRCL/SRCL gain measurements, and the SRCL gain measured just before I finished (second left hand side).

TITLE: 08/13 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY:

HAM7 close out work with both doors being installed and even the Annulus Ion Pumps pumping on the doors

Detector locking had DRMI locks---longest was around 5min!  So troubleshooting continues.
LOG:

• Before shift Randy moved forklift to East Bay near HAM7
• 1412 BS ISI tripped.  1546 Camilla untripped the BS and it returned to FULLY ISOLATED NO ST2 BOOST
• 1458-1605 tech cleaning (kim)
  • 1620-1702 FCES cleaning (kim)
• 1504-1520 checking "lvea local" laser status (corey)
• 1525-1718 HAM7 closeout work:  backscatter meas (sheila.camilla.ryanS)
• 1542-1552 Rehoming a snake from LVEA north bay outside 
• 1600-1612 transitioning East Bay back to Local Laser Hazard (barriers back up, signs flipped to laser hazard, and remove covers for beam from HAM7 to HAM6 in-air; last night this area was made SAFE for forklift move for Randy this morning (camilla)
  • Reservation System noting LVEA Local is HAZARD
• 1655-1800 FAMIS checks (chris)
• 1705-1711 opening Ion Pump at HAM1 (gerardo)
• 1715-1744 Transitioning LVEA East Bay back to SAFE (camilla)
• 1718-1724 Beckhoff restart (for JAC heater) [Daniel]
• 1720-1728 Picking up PSAMs part in east bay (ryanC)
• 1726-1730 LVEA walkthru (betsy)
• 1732-1911 Unlock, balance, & run post-chamber-close measurements (jim)
• 1756-1803 LVEA walkthrough looking for IAS stuff (jason)
• 1804-1858 Inventory checks (mitch)
• 1840-1847 Checking CRS connections out at rack (shoshonna,huyen)
  • 1859-1904 heading back in  (shoshonna,huyen)
• 1843-1850 bypass HAM7 high voltage (fil)
• 1854-1909 measuring cables in lvea (carlos)
• 1906-1950 ground loop checks at rack (fil.betsy)
• 1915-1940 Turning laser off at rack (shoshonna,huyen)
  • 2012 Turning on at the rack (shoshonna)
• 1920-1938 Moving a table out of the way at HAM7 (camilla)
• 1928-1943 Grabing something (washer) out from the bottom of HAM7 (jim)
• 1932-2325 Prep/Install both HAM7 doors and start pumping down AIPs to check doors.  Also installed flanges on HAM7 west door (randy)
  • 1940 travis joining
  • 2000-2325 gerardo joining
  • 2141 Randy out (both doors on)
• 1949-1953 grab pelican case (ryanC)
• 1957-2016 Dropping off large item in the recycling bin outside of hi-bay (christina)
• 2203-2220 Picking up pans/parts around HAM7 (ibrahim)
• 2307-2312 fixing accelerometer cables in CER (dave.miranda)
• 2322 CRS measurements at CER & HAM3 rack (shoshonna,huyen,jim)

• Watching the CRS laser since it's been installed, we've noticed some mode hopping occurring where there are these dramatic jumps between wavelengths (picture 1) or small just happening very frequently (picture 2)
  • This morning we added some thermal paste and some scrap metal on the CRS laser to try and help with the thermal regulation. 
• I looked back at the time series from when the NRS laser was plugged in and while there is still some mode hopping occurring, it doesn't have the same big hops, rather smaller ones which occur much less frequently (picture 3).
• While power cycling the TEC, we found that the mode hopping in the CRS laser reduces if the TEC is set to 10.896kΩ-10.899kΩ (rather than the recommended  10.72kΩ).  If the value is between 10.72kΩ and 10.896kΩ or above 10.899kΩ, the mode hopping worsens. In this range the mode hopping looks more like the NRS laser mode hopping (picture 4) with the occasional big jumps, but much less frequently than with other TEC settings.
  • Using 10.896kΩ the laser temperature is set to 24.42^o C, rather than 24.5^oC when the TEC is set to 10.72kΩ
• We'll keep an eye on the performance and the amount of noise hopping as 
• While it's good to have reduced the amount of mode hopping, it doesn't seem to improve the actual CRS performance, which is as expected given the NRS laser didn't improve the performance. At this point it seems like the excess noise isn't from the laser itself or the thermal regulation of the laser and is from something else.

Fil, Betsy

Today Fil and I did a quick repeat of T2200048 HAM7 ground loops check just before doors are going on.

Last checks were done:

Feb this year by Camilla/Sheila https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=89048

Feb 2022 Fil/me https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=61738

Keita had done them prior, hence the document.

We basically found the same results as Camilla/Sheila namely:

• ISC_SQ_479 and ISC_SQ_480 have pins 13 and 23 connected 
• ISC_SQ_483, ISC_SQ_303 and ISC_SQ_481 have pin 13 and rack ground connected 

All the rest were "open".

In our PRMI locking today, Sheila had me compare some signals from today to a past PRMI time and pointed me to alog91238. We weren't sure however if these numbers made sense, so I found another PRMI time from November (specifically Nov 26th, GPS 1448216615, PRMI ASC converged) and re-did the comparison to today.

Masayuki, Sheila

When we step the alignment sliders in pitch or yaw on PR2, we see 1 Hz ringing for 15-20 seconds.  

Keita, Sheila, Tony,  Jennie W

Before the JAC PZT problem, I did get an hour or so of alignment time in.  Summary: we now have light on LSC POP and POP X for the same PM1 alignment, and ITMX is back to the alignment that should point down the arm.  We have the expected power in LSC POP path, but a factor of 20 too small in both DC and RF signals in the popair path. 

These screenshots show MICH fringes with 10W input power, where I started and where I ended.  The idea was to move to the ITMX alignment that Jenne Driggers found using the arm beam here: 89738.  I watched the mich fringes and AS camera while moving the ITM, moved the beam splitter to keep the michelson fringes, and as Keita suggested moved PR3 to keep the beams on the ISCT1 refl camera.  This did cause the michelson fringes on the LSC pop diode to get smaller, when that happened I paused, went to the PR2 spot move guardian state, and adjusted PR3 to bring the fringes back on LSC POP.  After bringing the ITMX yaw alignment back I could see that there is now light on POPX and LSC POP A for the same PM1 alignment.  

When I walked ITMX pitch, I had to also adjust yaw several times as I went along to keep the mich fringes.  I also adjusted PRM to keep PRX alignment good as I moved along. Looking at this screenshot of the brief time when PRMI was flashing, the POP A LF flash was about the O4 power level (91211), as was reflair A, but popair has too little power.   The result of this was that PR3 started the day 56urad away from the O4 slider, but is not -15urad.  PR3 yaw started the day close to the O4 slider but is now -47urad.

I also adjusted the POP X dark offsets so that this QPD will be less confusing to read, SDF screenshot attached.

We tried walking PR3 in PR2 spot move to allow us to centering POP X without saturating PM1, this alignment is shown in this screenshot, but when we then aligned PM1 to put the beam on LSC POP, we were missing power there.