Sina, Jim

We tested the functioning of the picomotors in the LIGO-SPI Pathfinder ISIK and ISIJ assemblies. All motors are working (see attached video).

Sina, Jeff

The photodetector chassis of the LIGO-SPI pathfinder has been modified to maximize the CDS range. The TIA is designed to put out 0V - 10V on the positive leg of the differential output. The power monitoring PDs are set to get close to 5V, the interferometer PDs a mean of 2.5V, and the QPD quadrants 3.5V each. The whitening filters for the heterodyne-interferometer photodiodes are bypassed. The details of the installed capacitor and resistors are listed in the following table:

The capacitor for the QPDs might be changed to result in a low-pass frequency of 10 kHz at a later date.

After the vacuum team opened up GV7 so that we can have a peek down the arm, I ran the green baffle PD scripts for the Xarm.

I did the usual misalign ITMX and ETMX, and ran the script for TMSX.  I then realigned ITMX, and ran the script for ITMX.  I then realigned ETMX and ran the script for ETMX.  

I looked at H1:ALS-X_REFL_A_DC_POWER and moved ETMX a bit to try to get some refl dips, which indicate that there are some flashes in the Xarm.  ETMX is not at all optimized, and I haven't touched TMSX since running the baffle align script on it. 

The baffle align script moved ITMX 5 or 6 urad "down" in yaw, and very little in pitch.  The attached screenshots shows times before, during, and after the baffle align script, for the ITMX sliders, top mass osems, and oplev.  The only difference between screenshots is whether cursors are included for convenience.

Sheila,  Camilla 

Yesterday, Sheila moved ZM3 in steps of +10urad in PIT on the sliders (towards the diorection we know we need to be for SQZT7 light). She then compensated with FC1 and FC2 to maximize FC green flashes each time. And then measured the amount ZM3 needed to be moved to get light on SQZT7, ZM3 needed to be moved less each time to get light on SQZT7 IR PD (good) however, the flashes could not be brought back to thier maximum (bad). Plot attached.

Today, I moved ZM3 in steps of -10urad in PIT on the sliders (away from the diorection we know we need to be for SQZT7 light). Then compensated with FC1 and FC2 to maximize FC green flashes each time. And then measured the amount ZM3 needed to be moved to get light on SQZT7, ZM3 needed to be moved slightly more each time to get light on SQZT7 IR PD (bad), but the flashes could be brought back to thier maximum and mayeb even got slighly better (good). Plot attached

For the HAM1 work today, here are two screenshots showing PRX alignments with two different PR3 values.  

PR3 yaw slider at -233.7 urad is here, since HAM2 HEPI is locked 3.7 urad positive RY compared to it's usual location (89701), this corresponds to -230 urad our yaw alignment from O4 (and from the March 14th PRMI/DRMI locking).  

PR3 yaw slider at -240, here, is the alignment for which in the in chamber crew found the beam on the edge of the ASC POP X diode.  

[Keita, Oli, Jenne]

To make relocking the IMC easier during the HAM1 work, JM3's damping has been significantly increased.  Oli did mention that the JM3 damping loops haven't seen much real tuning yet, so even when we discontinue this overdamping, we may want to spend some time on them.

Attached are screenshots of JM3's damping loops before we tuned anything, as well as how we're leaving JM3 overdamping for now. 

The spectra show JM3 damping, but with gains of -2 in each of the Pit and Yaw loops as the references (so, a little more damped than they were yesterday), and then the live traces are with the overdamped situation.  

As a comparison, Oli pointed me to this old alog 62672 with a similar suspension's damping loops measured. 

Wed Apr 01 10:14:14 2026 INFO: Fill completed in 14min 11secs

On Monday I had a good alignment for the FC, see 89694  and that alog's attached screenshot. Yesterday we went there and had to touch up FCs a little to get flashes. Today for the same sliders was even worse witha very PIT misalinged FC Green beam, see attached, in the same FC1 PIT slider potion, the osems were 150urad off, attached. When I brought us back to the top mass osem positions for all optics (ZM1,2,3,FC1,2 and ZM2 PSAMS) we have no green flashes in the FC, just a single pass green beam, attached. 

1.  Why is the FC1 top mass osems drifting 150urd in 24 hours
2.  We don't seem to be able to trust the osems as going back to them gives us no FC flashes.

Rahul did in-air TF's 75830

For FAMIS #39861: Fans look mostly flat (Corner's FAN5 looks faintly noisier the last 1.5 days).

Attached are monthly TCS trends for HWS & CO2 lasers.  (FAMIS link)

TITLE: 04/01 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: 5mph Gusts, 2mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.19 μm/s 
QUICK SUMMARY:

HAM1 JAC alignment work continues (I pressume similar for SQZ alignment.)   There is a plan to swap out a ceiling HEPA Fan for the anteroom of the H1 PSL enclosure this morning.  Also prep for HAM3 venting is on the docket when HAM1 work completes (i.e. lock HEPI, chamber cleaning, etc.)....and  also venting the corner as well. 

LVEA is still Operations laser SAFE (or bifurcated for HAM1 + SQZ work and laser goggles required at height).  Warmer this morning April Fool's Day and rainy.

Jennie W, Keita K, Jason O, Jenne D,

Once we got the locking of JAC and IMC working at 20W this morning, Keita went into the chamber while we had PRMI aligned to check the POP beam alignment in HAM1.

We had trouble keeping the IMC locked when Keita was moving next to the chamber, JAC occasionally unlocks but is staying locked for long periods. I hypothesise that JM3 moving around is more of a problem than JM1 because of this. Eventually we managed to stay locked with 4W while Keita was in chamber. Over this period Keita realised the beam was mis-aligned coming out of the POP periscope and so we used PR2 and PR3 yaw to walk the beam back till it was well centred on AS AIR camera and we still saw flashes. Eventually we mis-aligned ITMY and just used PRX flashes. We had to move 10 microradians on PR2 and then correct with 1 microradian on PR3 to maintain the alignment.

I put the power up to 10W from 4 W and we saw a power change on ASC-POP_X.

To see if we could recover alignment onto POP-X with PM1 we put the PM1 yaw up to a high value so it was railing and we did see some counts on ASC-POP_X QPD SUM but we cannot point the beam onto the diode before PM1 rails so we undid this.

The day ended with a total move of -120 on PR2 yaw, -12 on PR3 yaw, -8.1 mircoradians on PR3 pitch, and +81 microradians on PR2 pitch. Keita can now see the beam on the side of the ASC POP X QPD.

The pitch changes we did at the end of the day were to try and improve the steering to ASC POP X but we didn't get time to optimise this so we can undo them tomorrow if necessary.

Summary: Checking POP is hard as the IMC will unlock very easily if someone is in HAM1, probably due to shaking of JM3. We need to work out if we trust the PRC alignment axis or if we want to cross-check it with something else (like the ALS beam from the X-arm) before we continue debugging.

(Jordan V., Travis S., Gerardo M.)

We removed and replaced the broken pressure regulator for GV7, we haven't tested the new regulator yet (open or try to hard close GV7), but hope to do so soon. During the regulator replacement we installed an isolation valve on the line that feeds GV7, this for upcoming work on this system.
While doing the replacement of the regulator for GV7, we discovered that the pressure regulator for GV8 pneumatic system is broken too, currently it is reporting a max pressure of 100 psi and a low pressure of 80 psi, it rides the instrument air compressor behavior (high and lows).  We tried to lower the pressure but the regulator is non-responsive.  We'll replace the pressure regulator at the next opportunity.  Also, it turns out that the pressure regulators attached to the different pneumatic gate valves are not the same model.

Following the B13, B2H34 and H12 upgrades in Dec 2025 and Jan 2026 today I did a second round of verification that the IOP models were reading the correct ADC channels and that the MEDMs were correct. The IOP models are correct and no changes were needed.

Some MEDMs had white-boxes for the raw ADC counts, which was addressed. The SWWD MEDMs use macro file substitution for the detailed screens, and the differences that now exist between the sites means it is no longer feasible to maintain these files in the cds/common/medm/ area. Today I moved them to cds/h1/medm before making the final updates.

At this time all the MEDMs are correct with the exception of the BS IPC channel for SUS-BS to SEI-BSC2. h1iopsusb2h34 has a simulink copy-paste error, the channel which should be BS_WD_SND but is actually BS_WD_SND1, hence the white-box.

I'm also reminded that during these upgrades we decided to not change the IPC channel names in order to minimize the scope of work, so IPC names containing B123, H2A, H34 still exist. During the next RCG upgrade we will correct the names.

An overview of the SWWDs at both sites can be found in the DCC T2600106

TITLE: 03/31 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

Lots of subsystem work going on today.  The JAC team continued their alignment work at HAM1.  SQZ team continued alignment work at SQZT7 and then in the Control Room.  SPI team was in the Optics Lab most of the day.

Tomorrow morning a new HEPA fan will be installed for the h1psl room's anteroom....so it shouldn't affect HAM1 work.
LOG:

• 1411-1500 LVEA technical cleaning (nellie.kim)
  • Held off cleaning top of HAM3, since HAM3 was unlocked  (they noticed the signs saying so at HAM3), AND bifurcated Laser Safe requires goggles at-height, but that makes it unsafe to see things when climbing on top of a chamber.
  • 1515-1635 EY & returned to get keys! (nellie)
    • 1635-1648 FCES (nellie)
  • 1629 Kim out of lvea
    • 1718 EX cleaning
• 1445-1535 handrails on eMod platform (randy)
• 1516 Opening light pipe (sheila)
  • 1519 NOTE:  Sheila noticed a small puddle around the entry to the LVEA (under chiller piping?).  She wiped it up, but would like spot to be checked later.  There was cleaning in lvea earlier.
    • This is most likely just  from cleaning/mopping earlier (richard & kim checked)
• 1535-1540 Optics Lab pop-in (camilla)
• 1540-1618 climbing HAM3 for LO1 (fil)---->PR2, MC2 to SAFE
  • 1618-1730 susR2 work near HAM3 (fil)
• 1544-1606 Opening -Y cloth cover for in-air JAC & locking (jenne)
• 1547-1620 Monthly fire pumps run (eric)
• 1548-1614 both mids for inventory (jordan)
  • 1614-1618 PCal Lab room inventory (jordan)
• 1613-1800 LN2 truck MX
  • ~1645-1811 LN2 truck at Corner's CP1
• 1615-1620 Taking First Contact to flamable cabinet (ibrahim)
• 1616 BHSS work (elenna.camilla)
  • 1623 oli joining
  • 1857 Out for lunch, laser SAFE!
• 1627-1645 Checking on fil (richard)
• 1634-1725 lvea Receiving and then to MX to grab a BS container (ibrahim)
  • 1725 continue BS container search in optics lab (ibrahim)
• 1658-1912 GV7 regulator (gerardo.travis.jordan)
• 1703 Grabbing nd filter in optics lab & taking to IOT1/JAC table (jennie)
  • 1809-1920 Grabbing another nd filter to use at IOT1 (jennie.sheila)
• 1721 turning down purge air down at HAM1, checking rack (keita)
• 1804-1814 PCal (tony)
• 1808-1816 Rosalind Franklin Elementary in Control Room Group1 (amber)
  • 1830--1842 Rosalind Franklin Elementary in Control Room Group2 (cassidy)
• 1914-1932 TCS Chiller maintenance check (corey)
• LUNCH Note:  IMC locking, JAC locking---> next check on beam
• 1958 BHSS Work continues in laser hazard (elenna.oli)
• 1958-2001 quick trip to CER for dustmonitor (ryanC)
  • 2056-2100 Another dust monitor trip (ryanC)
• 2006-2259 SPI work in (jim, sina)
  • 2020 Jeff joining
  • 2124 Jeff returning again
  • 2255 Jim & Sina out for assistance with the in-vac picomotors
  • 2319 Jeff out for the day
• 2006 JAC work at HAM1 (keita, jennie)
  • 2037 jason joining
• 2007 HAM1 photo & then optics lab (josh.georgia.michele)
• 2031-2200 Grabbing HEPA Ceiling Fans from the H2 PSL  room in the LVEA (tyler.eric)
  • 2138 eric out
  • Plan to install one in H1PSL tomorrow (Wed) morning
• 2105 Back to susR2 rack near HAM3 (fil)
• 2114-2232 SQZT7 work (sheila.georgia.sophie.camilla)
  • 2233 sheila and camilla continue sqz work in control room
• 2153-2203 Touching base with JAC crew at HAM1 about a possible guardian change (jenne)
• 2225 Elenna checking to see if she can help the HAM1 crew on Betsy's request
• 2259 SPI crew (jim.sina) asking keita (at HAM1) about picomotors 

Addressed TCS Chillers (Wed [Mar4] 1242-0105pm local time) & CLOSED FAMIS #28559.  (Last checked 28558). 

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

• TCSx Chiller:  Had level of 30.4 cm.  Added 0mL for 30.4cm.
• TCSy Chiller:  Had level of 9.5 cm.  Added 325mL for 10.5cm.  
• There was no water in the small cup under the slow leak.

Sheila, Keita, Jennie W, Jenne D, Georgia B.

We want to be able to power up to 20W in JAC to check the POP beam.  

We were loosing lock with about 8W into JAC because the REFL shutter was closing.  Jennie Wright measured 6mW on the REFL diode with 2W input to HAM1 and JAC unlocked yesterday.  This corresponds to 0.58V on the shutter trigger diode.  The threshold cannot be set above 2V, which means we would unlock when 21mW hit the diode.  Jennie Wright added a ND05A into the path before the refl diode, and another ND05A in front of the shutter diode.  

Now, with 2W input to HAM1 and JAC unlocked, we should have 2mW on the REFL diode, and the shutter diode votlage is 0.18V.  The threshold of 2V now will shut the shutter with 22mW on it. 

Gaurdian changes:

The JAC error signals are normalized by the PSL input power if we use the laser power guardian to change the input power, so we shouldn't need a power scaling like 89708.  People have been using the rotation stage instead of the guardian to adjust the power because the laser power guardian would go into fault if the power was below 1W (people have been going below 1W while HAM1 is vented.)   Jenne Driggers adjusted the fault in LASER_POWER and added a 200mW state to the laser power guardian, so now we should use this guardian whenever we want to change powers, even below 1W. 

We also hard coded the gain used for locking JAC in the down state, although this could be reverted to allow the power normalization to work again, once that has been updated to take into account the new ND filters.  Once this was done, we could lock JAC at a variety of powers and also change the requested power after it was locked. 

Georgia B and I also had a look at the IMC guardian, which has not generally been able to lock the IMC except at 2W.  There was some code in the down state of IMC LOCK that was supposed to adjsut settings for lcokign at different power levels, these were unused except for the IN1 gain setting used for acquisition.  Georgia and I adjusted some of these numbers and watched if the IMC would lock, we didn't take much time to test it but we did once twice see the IMC lock with 10W + input power, so that is promising.