Lockloss

Lockloss at 2025-08-12 21:12UTC after 25 minutes locked

SQZ Pump Path Alignment Adjusted

Sheila, Jennie, Matt, Camilla. WP#12750

Followed what we did in 82881, but did not need to adjust alignment through the EOM. 

Starting with:

• 89mW into EOM, 85mW out of EOM.
• With 5V on ISS AOM controlmon: 22mW in 0th order and 9mW in first order beam.
• With 0V on ISS AOM controlmon: 33mW after AOM

Then with 0V on ISS AOM controlmon, increased to 73mW (85% throughput). Then put 5V on controlmon and started to maximize the 1st order beam. We decided to not completely maximize 1st order as this reduces overall throughput and our current aim is to increase total green throughout, not ISS AOM range.

Ended with:

• With 5V on ISS AOM controlmon: 40mW in 0th order and 13mW in first order beam.

Sheila then adjusted the alignment into the fiber and maximized H1:SQZ-OPO_REFL_DC_POWER from 1.55 to 2.8. 

This allowed us to have an OPO setpoint of 80uW with 20mW going into the fiber, wirth 5 on the controlmon and a spare 20mW that we could give to the fiber.  Note that after ~1hour when we got to NLN, the controlmon had decreased from 5 to 2.5. So the power to the AOM may need to be increased next time we loose lock. Maybe with SQZT0 temperature changes now doors are on and fans are off. 

There was a high pitched noise in SQZT7, close to the -Y side of the table, we couldn’t figure out what it was and maybe will have someone from EE help us with it another week. 

I ran the SCAN_OPOTEMP guardian state (twice as it was far off) once we wer close to NLN.

CDS Maintenance Summary: Tuesday 12th August 2025

WP12746 h1omc0 Low Noise ADC Autocal Test

EJ, Jonathan, Dave:

For a first test we restarted h1iopomc0 three times to run an autocal on the low-noise ADC -- each time the autocal Failed. Next test will be to power cycle existing card leading to possible replacement.

WP12755 TW1 Raw Minute Trend Offload

Dave:

h1daqtw1 was configured to write it raw minutes into a new local directory to isolate the last 6 months of data from the running system. The NDS service on h1daqnds1 was restarted to serve these data from this location while the file transfer progresses.

Restarts

Tue12Aug2025
LOC TIME HOSTNAME     MODEL/REBOOT
09:06:26 h1omc0       h1iopomc0   <<< three ADC AUTOCAL tests
09:08:12 h1omc0       h1iopomc0   
09:08:58 h1omc0       h1iopomc0   
09:09:12 h1omc0       h1omc       <<< start user models
09:09:26 h1omc0       h1omcpi     
11:51:19 h1daqnds1    [DAQ] <<< reconfigure for TW1 offload
 

LVEA Swept following T1500386

Unplugged an unused extension cord by the PSL racks. 

High bay and LVEA and entrance lights turned off, paging system off. Oli checked WAP is off.

Everything else looked good.

Beamsplitter ADS convergence in initial alignment taking too long

Today Oli and I saw that the ADS convergence checker for the beamsplitter was taking forever to return True during initial alignment, despite the fact that the signals appeared well-converged. The convergence threshold is set on line 1158 of ALIGN_IFO.py, and it is 1.5 for both pitch and yaw. Watching the log, the yaw output seemed to quickly be below this value, while the pitch output hovered between about 1.8 to 6. I tried raising the value to 5, but pitch still stayed mostly above that value. I finally changed it to 10, and the state completed. Overall, we were waiting for convergence for over 16 minutes. It seems like the convergence values for pitch and yaw should be different. It took about two minutes for the pitch and yaw ADS outputs to reach their steady value. On ndscope minute trend, the yaw average value appears to be around zero, while for pitch the average value is around -4. The convergence checker averages over 20 seconds.

The value is still 10, but that might be too high.

Field Cabling for JAC Tip/Tilts

WP 12749
Drawing D0902810-v11

Installation of the field cabling for the JAC tip/tilts completed. Cables pulled from the CER SUS-C3 rack to the SUS-R1 field rack. The DB25 cables going from the Sat Amp chassis were pulled to to the HAM1 D4 and D6 flanges.

F. Clara, M. Pirello, D. Sigg

Field Rack SUS-R7

WP 12756
Rack and Cable Tray Layout D1002704-v8

A new electrical rack was positioned next to the SUS-R4 rack. The new rack will be designated as SUS-R7. Installation of cable tray, DC power strips, power junction box will be installed in the upcoming weeks.

Randy, F. Clara, J. Figueroa, and M. Pirello

PSL FSS RefCav Tune-up (WP 12751)

The FSS RefCav TPD has been on a downward trend again, so I tuned up the alignment on the PSL table this morning.  All work was done with the ISS ON and diffracting ~3.8% unless otherwise noted.  As usual, I began with a power budget of the FSS path:

• FSS In: 273.8 mW
• AOM In: 273.1 mW
• AOM Out, Single Pass: 188.6 mW
  • Single Pass Diffraction Efficiency: 69.1%
• AOM Out, Double Pass: 135.0 mW
  • Double Pass Diffraction Efficiency: 71.6%
• EOM Out: 135.0 mW

The AOM's single pass diffraction efficiency was a little low, so I touched up the AOM alignment to improve it.  I also tweaked the alignment of mirror M21 (that reflects the RefCav beam back through the AOM for the double pass) to improve the double pass diffraction efficiency (since the AOM moved).  Finally I slightly tweaked the EOM alignment to center the beam on the input and output apertures and measured the power transmitted through the EOM:

• AOM Out, Single Pass: 196.3 mW
  • Single Pass Diffraction Efficiency: 71.9%
• AOM Out, Double Pass: 137.9 mW
  • Double Pass Diffraction Efficiency: 70.2 %
• EOM Out: 138.1 mW

I then tweaked the alignment into the RefCav using the alignment iris and manually tweaking the picomotor-equipped mirror mounts.  The RefCav locked on the first attempt, with an initial TPD of ~0.735 V.  I then used the picomotors to fine tune the alignment and managed to get a TPD of ~0.845 V.  To end, I unlocked the RefCav and tweaked the beam alignment onto the RefCav's RFPD, then measured the RefCav visibility using the RFPD voltage:

• Unlocked: 1.176 V
• Locked: 0.197 V
• Visibility: 83.2%

I then turned off the ISS (we turn it off while the enclosure returns to thermal equilibrium, because during this process the PMC transmission can change; we don't want the ISS to actuate on the laser power until things stabilize), left the enclosure, and returned it to Science Mode operation.  I let the enclosure return to thermal equilibrium for about an hour and then checked on things.  When I turned the ISS back ON I had to increase the ISS RefSignal from -1.99 V to -1.98 V to hold our diffracted power at ~4%.  I then did on final tweak of the RefCav alignment using our picomotor mirrors; I was able to get the RefCav TPD up to ~0.854 V.  At this point the RefCav tune up is complete and the PSL is ready for post-maintenance IFO recovery.  This closes LHO WP 12751.

Tue CP1 Fill

Tue Aug 12 10:07:51 2025 INFO: Fill completed in 7min 48secs

 

Lockloss

Lockloss at 2025-08-12 14:57UTC right before the start of maintenance. Haven't looked yet to see if it was caused by the SUS charge meaurements or by something else

Ops Day Shift Start

TITLE: 08/12 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 12mph Gusts, 6mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.13 μm/s
QUICK SUMMARY:

Currently have been Locked for over 5.5 hours and out of Observing to run injections

Mon EVE Ops Summary

TITLE: 08/12 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 147Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY:

Very easy shift with H1 locked over 11.5hrs (we've also "cooled" down to 85degF!)
LOG:  n/a

 

SPi Optomechanics: Picomotor Assembly Components

J. Kissel, C. Compton

Camilla and I took some pictures of what supply of picomotor assembly materials we (existing ICS Supply vs. what SPI) have and in what state of assembly they are in order to familiarize myself with the process of building up new assemblies. 

To the best of my knowledge, there's no assembly procedure. Instead, we have the Picomotor Fact Page (E2100196) [which I've, as of this aLOG, heavily updated / curated]:
    - A well-labeled exploded assembly drawing with only minor assembly errors, (Page 2 of D2100433)
    - a hand illustration from Rich on the wiring connections for an IXM100.C2, right-handed mount (D1400279) 
    - the expected two-motor pinout of the receiving D25M to 4x MM4F quadrapus cable (D1101516) 
    - Some instruction on how dis-mount and re-mount fully assembled picomotors (E2500163)
and thru a linear combination of these, you could fumble your way through it.

The picomotors themselves have evolved over the years as the original prefer vendor, New Focus, was bought out by Newport. 
:: First picture shows the difference between an old picomotor (left), and the modern 8301-UHV-KAP that we buy now (right). I've created D2500246 (as opposed to the old, non-specific E1000197) that captures the specific features of this model. The key differences between old vs. new being
    - The wires' insulation is kapton, not colored teflon
    - The wire lengths is a nice healthy 7 [in], not a short 2 [in] that required icky extension
    - The label of which wire is which is stamped into the metal (a "-" in the lower-left corner to indicate that the wire closest to that stamp is the negative lead, or "return") vs. indicated by color of wire.

:: Second picture shows the modern 8301-UHV-KAP picomotor by itself. Note, the "1" in 8301 indicates that we've chosen the 0.5" throw.

:: Third picture shows the cable unfurled and compared against the 1 [in] hole pattern of the optical table beneath the foil.

OK, now that you've gotten to know the raw picomotor, let's talk about cnonnectorizing and modifying it to suit our needs. We only have the old style picomotor fully assembled to picture as example, but it'll serve the purpose.

:: Fourth picture shows the real manifestation of Rich's artist impression of the fully connectorized two-motor system.

:: ECR E1400327 has us install a motion limiting shaft collar along the throw of the picomotor to limit the motion from the edge of its range where it's been found to get stuck. The collar was originally a custom D1400189 per -v1 of the ECR, but now it's a stock McMaster Carr shaft collar (6436k131, with the black-oxide steel #4-40 x 3/8 [in] L SHCS replaced with a stainless, otherwise identical, SHCS, 92196A108). The stock collar is then modified to be a bit thinner, per D1800220. Finally, to prevent the shaft collar from freezing against the picomotor body, we install a slip-on LIGO-cut kapton "washer" (D1400226; cut from 12 [in] x 12 [in] x 0.005 [in] sheet stock) around the threaded adjustment screw.
    - Fifth and Sixth pictures show how the shaft collar is shaved thinner,
    - Seventh picture shows the Kapton washers,
    - Eighth picture shows the collars assembled on the motor, and where the washer would be placed (these didn't have washers at the time of the picture, but we've since installed the on their to form a complete, albiet not-so-vacuum-compatible assembly).

:: Once connectorized, per Rich's drawing, to the 4-pin MMF connnector 803-003-07M6-4PN-598A, then the connector is secured to a custom L-bracket D1002763 via the connector's thumb screw. That L-bracket then secures to the optic mount's "other" 1/4"-20 mounting hole (with "the" 1/4"-20 mounting hole, 90-deg away, is presumably used to secure the mount to a post or breadboard). Note -- the L-bracket's thru-hole for the MM connector is keyed, but it's not sized for any feature on the actual connector, so you're free to orient the connector in any way in within the bracket. Of course, each socket connector on the legs of the quadrapus it'll connect to are much better keyed, so there's no worry of pin-clocking or anything nasty like that.
    - Ninth picture shows the D1002763 L-bracket. Note -- this a D1002763-v2 Type 1 bracket, so it's mounting hole is threaded for 1/4"-20 bolt (rather than Type 2 which has a thru-hole requiring a nut).
    - Tenth, Eleventh, Twelth, and Thirteenth pictures show how the MM connector is assembled on to that portion of the D1002763 L-bracket.

Finally, just because it came up during the pre-clean-and-bake inspection (see discussion in CNB:2225), 
    - Fourtheenth picture shows the inside of the 803-003-07M6-4PN-598A MM connector -- a  black plastic that Glenair calls a "High Grade Rigid Dialectric," without specifying the material (see table in Section 3.1 on page 2 of Mighty_Mouse_Series 80_performance-test-report-iaw-mil-dtl-810.pdf from T2500025). 
I mostly show the picture of the old connectorized picomotor system to indicate that we've indeed been using this connect and its inner material for a long time, and the Clean-and-bake process (T2100001) appears to be enough (see e.g. bake loads ICS:10543 and ICS:10557).

Mon Eve Ops Transition

TITLE: 08/11 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 147Mpc
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 11mph Gusts, 7mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.17 μm/s
QUICK SUMMARY:

H1's been locked almost 7hrs and Tony took care of the SQZ guardian thing they discovered during the day shift (yay!).  With just that said, it's smooth sailing thus far.

Monday Ops Day Shift report.

TITLE: 08/11 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 147Mpc
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY:
Power supply issues as soon as I walk in.

Viewports got covered by Robert.
Fil got the 18V power supply working again, and we started to relock but got stuck in AS Shutters because a PST driver was still not yet powered because it's breaker had tripped.
Alogs:  86290 & 86296

NLN reached by 17:21:50 UTC.
Comissioners Comissioned some Scattered Light Investigations and some quasi anti-SQZin.  

Observing reached by 19:47:01 UTC

Dropped from Observing due to the SQZ_MAN going to NO_Squeezin at 21:33:42 UTC for some strange reason. Mystery!
Back to Observing at 21:38:43 UTC after requesting FDS.

Mystery solved! Ryan Short found out that when a Guardian node is stalled, the unstalling node calls a revive function which returns a node to the "Last Requested State".    
And since we were now in a strange state that may wake up the OWL Operator....
We resolved it By: 

UnManage H1 Manager.
Manual ISC_LOCK to Inject_Squeezing
Allow SQZ_MAN to reach FDS
Then Manual ISC_LOCK back to NLN.

LOG:
 

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
19:33	SAF	Laser HAZARD	LVEA	YES	LVEA is Laser HAZARD	11:33
15:04	PEM	Robert	LVEA	Yes	Closing View ports	17:04
15:22	Fast Shutter	Richard	Mech room Mez	n	Rebooting the Fast Shutter	16:18
15:29	EE	Fil	Mech Room Mez & LVEA HAM6	N	Working on Fast Shutter & PZT power cycle	17:29
15:35	FAC	Kim & Nellie	Mid X Mid Y	N	Technical Cleaning Kim out @ 16:18UTC	16:41
17:33	Optics	Kieta	Optics Lab	Yes	Working in the Optics lab	17:56
19:04	VAC	Janos	MY	n	Closing valve	19:21
19:38	SPI	Jeff	Optics Lab	yes	SPI inventory check	19:44
20:50	Tour	Mike & Tour Group	Control Room & Overpass	N	Leading a tour	22:50
22:27	SPI	Jeff	Optics Lab	Yes	SPI Inventory	00:27
23:06	ISS	Camilla	Optics lab	Yes	Working on some optics in the lab.	23:36

 

Estimating surface defocus of test masses and absorption from HOM spacing

M. Todd, S. Dwyer

---

As derived in previous alogs, we are able to relate the HOM spacing observed in each arm to the surface defocus of the test masses -- which is a combination of self-heating and ring heater power (ignoring CO2 affects on the ITM RoC). From the fits we've made of the HOM spacing / surface defocus change as a function of ring heater power we can get a value for the ring heater to surface defocus coupling factor.

Theoretically from this we should be able to solve for the self heating contribution in the test masses as well -- allowing us to constrain things like the coupling of absorbed power to surface defocus at the ITMs if we assume to know the arm power and absorption values (from HWS).

---

Upper Limits

If we assume no absorption in ETMs (obviously not physical), and we assume the HWS values for the ITM absorptions are correct, then with a HOM spacing measurement from each arm we can get an upper limit of the coupling factor of self-heating to surface defocus for each ITM (they shouldn't be different but this is a good exercise).

Assuming alpha is the absorption coefficient, i subscript is for the ITM, and x/y is which arm. P_y,i_rh is the itmy ring-heater. G-factors are the product of ITM and ETM g-factors. Then from the formula in section 1.2 of the notes file : Gy = Gyc - B*L*gyic*(Pyerh+Pyirh) - L*(Ai*alpha_yi*Pyarm*gyec + beta*Ai*alpha_e*Pyarm*gyic), we can solve for Ai which is the coupling factor of self-heating to surface defocus.

Parameter	Value	Notes
alpha_x,i	430 ppm	from alog 76937
alpha_y,i	375 ppm	from alog 76937
alpha_x,e	0 ppm
alpha_y,e	0 ppm
P_y,i_rh	0.000 W	T0 = 1417899757
P_x,i_rh	0.850 W
P_x,e_rh	1.950 W
P_y,e_rh	2.146 W
P_yarm	385159 W	T0 = 1417899757
P_xarm	385159	T0 = 1417899757
Gx	0.8149	T0 = 1417899757
Gy	0.8198	TMS * pi G    =   cos2 (   ----------------   )                       FSR
Ai_y	-26 uD/W
Ai_x	-39 uD/W

---

Middling Values

If we assume quoted absorption in ETMs (measured by LIGO, on galaxy), and we assume the HWS values for the ITM absorptions are correct, then with a HOM spacing measurement from each arm we can get a more realistic value of the coupling factor of self-heating to surface defocus for each ITM (they shouldn't be different but this is a good exercise).

Assuming alpha is the absorption coefficient, i subscript is for the ITM, and x/y is which arm. P_y,i_rh is the itmy ring-heater. G-factors are the product of ITM and ETM g-factors. Then from the formula in the notes file : Gy = Gyc - B*L*gyic*(Pyerh+Pyirh) - L*(Ai*alpha_yi*Pyarm*gyec + beta*Ai*alpha_e*Pyarm*gyic), we can solve for Ai which is the coupling factor of self-heating to surface defocus.

Parameter	Value	Notes
alpha_x,i	430 ppm	from alog 76937
alpha_y,i	375 ppm	from alog 76937
alpha_x,e	200 ppm
alpha_y,e	210 ppm
P_y,i_rh	0.000 W	T0 = 1417899757
P_x,i_rh	0.850 W
P_x,e_rh	1.950 W
P_y,e_rh	2.146 W
P_yarm	385159 W	T0 = 1417899757
P_xarm	385159	T0 = 1417899757
Gx	0.8149	T0 = 1417899757
Gy	0.8198	TMS * pi G    =   cos2 (   ----------------   )                       FSR
Ai_y	-16 uD/W
Ai_x	-26 uD/W

---

Summary

Both of these values indicate there is certainly an overestimation of the self-heating impact on surface defocus.

For reference, the current TCS-SIM values for this coupling factor are Ai_y = Ai_x = -36.5 uD/W.   More examination is required into this.

---

Links to previous alogs:

1. Estimating HOM spacing shift from self-heating alone:  https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=84172