J. Kissel

I've been looking through the data captured about the PMC in the context of the two years of observatory use between July 2022 and July 2024 where we spanned a few "construction, commission, observe" cycles -- see LHO:83020. Remember the end goal is to answer the following question as quantitatively as possible: "does the PMC have a high enough duty cycle in the construction and commissioning phases that the SPI does *not* need to buy an independent laser?"

Conclusions: 
 - Since the marked change in duty cycle after the PMC lock-loss event on 2023-05-16, the duty-cycle of the PMC has been exceptionally high, either 91% during install/commissioning times or 99% during observing times. 
 - Most of the down time is from infrequent planned maintenance. 
 - Recovery time is *very* quick, unless the site loses power or hardware fails. 
 - The PMC does NOT lose lock when the IFO loses lock. 
 - The PMC does NOT lose lock just because we're vented and/or the IMC is unlocked. 
 - To-date, there are no plans to make any major changes to the PSL during the first one or two O4 to O5 breaks.
So, we shouldn't expect to lose the SPI seed light frequently, or even really at all, during the SPI install or during commissioning. And especially not during observing. 

This argues that we should NOT need an independent laser from an "will there even be light?" "won't IFO construction / commissioning mean that we'll be losing light all the time?"  duty-cycle stand point.
Only the pathfinder itself, when fully functional with the IFO, will tell us whether we need the independent laser from a "consistent noise performance" stand-point.

Data and Historical Review
To refresh your memory, the major milestones that happened between 2022 and 2024 (derived from a two year look through all aLOGs with the H1 PSL task):
- By Mar 2022, the PSL team had completed the complete table revamp to install the 2x NeoLase high-power amps, and addressed all the down-stream adaptations.

- 2022-07-01 (Fri): The data set study starts.
- 2022-09-06 (Tue): IO/ISC EOM mount updated, LHO:64882
- 2022-11-08 (Tue): Full IFO Commissioning Resumes after Sep 2022 to Dec 2022 vent to make FDS Filter Cavity Functional (see E2000005, "A+ FC By Week" tab)
- 2023-03-02 (Thu): NPRO fails, LHO:67721
- 2023-03-06 (Mon): NPRO and PSL function recovered LHO:67790
- 2023-04-11 (Tue): PSL Beckhoff Updates LHO:68586
- 2023-05-02 (Tue): ISS AOM realignment LHO:69259
- 2023-05-04 (Thu): ISS Second Loop Guardian fix LHO:69334
- 2023-05-09 (Tue): "Something weird happened to the PMC, then it fixed itself" LHO:69447
- 2023-05-16 (Tue): Marked change in PSL PMC duty-cycle, nothing specific PSL team did with the PMC, but the DC power supplies for the RF & ISC racks we replaced, 69631, while Jason tuned up the FSS path LHO:69637 
- 2023-05-24 : O4, and what we'll later call O4A, starts, we run with 75W requested power from the PSL.
- 2023-06-02 (Fri): PSL ISS AA chassis it was replaced, but PMC stays locked through it LHO:70089
- 2023-06-12 (Sun): PMC PDH Locking PD needs threshold adjustment, LHO:70352, for "never found out why" reason FRS:28260
- 2023-06-19 (Mon): PMC PDH Locking PD needs another threshold adjustment, LHO:70586, added to FRS:28260, but again reasons never found.
- 2023-06-21 (Wed): Decision made to reduce requested power into the IFO to 60W LHO:70648
- 2023-07-12 (Wed): Laser Interlock System maintenance kills PSL LHO:71273
- 2023-07-18 (Tue): Routine PMC / FSS tuneup, with quick PMC recovery LHO:71474
- 2023-08-06 (Sun): Site-wide power glitch takes down PSL LHO:72000
- 2023-09-22 (Fri): Site-wide power gltich takes down PSL LHO:73045
- 2023-10-17 (Tue): Routine PMC / FSS tuneup, with quick PMC recovery LHO:73513
- 2023-10-31 (Tue): Jeff does a mode scan sweeping the PMC FSR LHO:73905
- 2023-11-21 (Tue): Routine PMC / FSS tuneup, with quick PMC recovery LHO:74346
- 2024-01-16 : O4A stops, 3 months, focused on HAM567, no PSL work (see E2000005, "Mid-O4 Break 1" tab)
O4A to O4B break lock losses: 7
       2024-01-17 (Wed): Mid-vent, no IFO, no reported cause.
       2024-01-20 (Sat): Mid-vent, no IFO, no reported cause.
       2024-02-02 (Fri): Mid-vent, no IFO, no reported cause.
       2024-02-08 (Thu): Mid-vent, no IFO, no reported cause. During HAM6 close out, may be related to alarm system
       2024-02-27 (Tue): PSL FSS and PMC On-table Alignment LHO:76002.
       2024-02-29 (Thu): PSL Rotation Stage Calibration LHO:76046.
       2024-04-02 (Tue): PSL Beckhoff Upgrade LHO:76879.
- 2024-04-10 : O4 resumes as O4B start
O4B to 2024-07-01 lock losses: 1
       2024-05-28 (Tue): PSL PMC REFL tune-up LHO:78093.
- 2024-07-01 (Mon): The data set study ends.

- 2024-07-02 (Tue): The PMC was swapped just *after* this data set, LHO:78813, LHO:78814

By the numbers

Duty Cycle (uptime in days / total time in days)
     start_to_O4Astart: 0.8053
    O4Astart_to_O4Aend: 0.9450
    O4Aend_to_O4Bstart: 0.9181
       O4Bstart_to_end: 0.9954
(Uptime in days is the sum on the values of H1:PSL-PMC_RELOCK_DAY just before lock losses [boxed in red] in the attached trend for the given time period)

Lock Losses (number of times "days" goes to zero)
     start_to_O4Astart: 80
    O4Astart_to_O4Aend: 22
    O4Aend_to_O4Bstart: 7
       O4Bstart_to_end: 1
(Number of lock losses is mere the count of red boxes for the given time period)

Lock Losses per calendar days
     start_to_O4Astart: 0.2442
    O4Astart_to_O4Aend: 0.0928
    O4Aend_to_O4Bstart: 0.0824
       O4Bstart_to_end: 0.0123
(In an effort to normalize the locklosses over the duration of the time period to give a more fair assessment.)

I also attach a histogram of lock durations for each duration, as another way to look at how the duty cycle dramatically changed around the start of O4A.

Closes FAMIS 28458. Last checked in alog 82659.

• CO2 IY and IX PD_OUT signals are constant rather than offset at week intervals compared to last month. I assume this is due to changes between Tuesdays.
• HWS SLEDPOWERMON signals for both IX and IY are continuing to go down very gradually as last month's trend showed.

This is for FAMIS #26370.
Laser Status:
    NPRO output power is 1.853W
    AMP1 output power is 70.51W
    AMP2 output power is 140.0W
    NPRO watchdog is GREEN
    AMP1 watchdog is GREEN
    AMP2 watchdog is GREEN
    PDWD watchdog is GREEN

PMC:
    It has been locked 30 days, 23 hr 28 minutes
    Reflected power = 22.36W
    Transmitted power = 106.5W
    PowerSum = 128.8W

FSS:
    It has been locked for 0 days 5 hr and 18 min
    TPD[V] = 0.7969V

ISS:
    The diffracted power is around 3.5%
    Last saturation event was 0 days 5 hours and 18 minutes ago

Possible Issues: None reported

Monthly FAMIS Check (#26499)

T240 Centering Script Output:

Averaging Mass Centering channels for 10 [sec] ...
2025-03-07 11:28:08.262570
There are 15 T240 proof masses out of range ( > 0.3 [V] )!
ETMX T240 2 DOF X/U = -0.975 [V]
ETMX T240 2 DOF Y/V = -1.02 [V]
ETMX T240 2 DOF Z/W = -0.554 [V]
ITMX T240 1 DOF X/U = -1.776 [V]
ITMX T240 1 DOF Y/V = 0.392 [V]
ITMX T240 1 DOF Z/W = 0.484 [V]
ITMX T240 3 DOF X/U = -1.843 [V]
ITMY T240 3 DOF X/U = -0.789 [V]
ITMY T240 3 DOF Z/W = -2.313 [V]
BS T240 1 DOF Y/V = -0.351 [V]
BS T240 3 DOF Y/V = -0.311 [V]
BS T240 3 DOF Z/W = -0.432 [V]
HAM8 1 DOF X/U = -0.317 [V]
HAM8 1 DOF Y/V = -0.434 [V]
HAM8 1 DOF Z/W = -0.712 [V]
All other proof masses are within range ( < 0.3 [V] ):
ETMX T240 1 DOF X/U = -0.006 [V]
ETMX T240 1 DOF Y/V = -0.014 [V]
ETMX T240 1 DOF Z/W = 0.009 [V]
ETMX T240 3 DOF X/U = 0.029 [V]
ETMX T240 3 DOF Y/V = -0.068 [V]
ETMX T240 3 DOF Z/W = -0.005 [V]
ETMY T240 1 DOF X/U = 0.082 [V]
ETMY T240 1 DOF Y/V = 0.171 [V]
ETMY T240 1 DOF Z/W = 0.24 [V]
ETMY T240 2 DOF X/U = -0.067 [V]
ETMY T240 2 DOF Y/V = 0.216 [V]
ETMY T240 2 DOF Z/W = 0.073 [V]
ETMY T240 3 DOF X/U = 0.26 [V]
ETMY T240 3 DOF Y/V = 0.114 [V]
ETMY T240 3 DOF Z/W = 0.146 [V]
ITMX T240 2 DOF X/U = 0.181 [V]
ITMX T240 2 DOF Y/V = 0.294 [V]
ITMX T240 2 DOF Z/W = 0.245 [V]
ITMX T240 3 DOF Y/V = 0.13 [V]
ITMX T240 3 DOF Z/W = 0.133 [V]
ITMY T240 1 DOF X/U = 0.082 [V]
ITMY T240 1 DOF Y/V = 0.123 [V]
ITMY T240 1 DOF Z/W = 0.04 [V]
ITMY T240 2 DOF X/U = 0.04 [V]
ITMY T240 2 DOF Y/V = 0.263 [V]
ITMY T240 2 DOF Z/W = 0.132 [V]
ITMY T240 3 DOF Y/V = 0.08 [V]
BS T240 1 DOF X/U = -0.161 [V]
BS T240 1 DOF Z/W = 0.156 [V]
BS T240 2 DOF X/U = -0.031 [V]
BS T240 2 DOF Y/V = 0.072 [V]
BS T240 2 DOF Z/W = -0.092 [V]
BS T240 3 DOF X/U = -0.139 [V]
Assessment complete.

STS Centering Script Output:

Averaging Mass Centering channels for 10 [sec] ...
2025-03-07 11:37:12.263138
There are 1 STS proof masses out of range ( > 2.0 [V] )!
STS EY DOF X/U = -2.334 [V]
All other proof masses are within range ( < 2.0 [V] ):
STS A DOF X/U = -0.503 [V]
STS A DOF Y/V = -0.757 [V]
STS A DOF Z/W = -0.603 [V]
STS B DOF X/U = 0.235 [V]
STS B DOF Y/V = 0.954 [V]
STS B DOF Z/W = -0.319 [V]
STS C DOF X/U = -0.862 [V]
STS C DOF Y/V = 0.801 [V]
STS C DOF Z/W = 0.681 [V]
STS EX DOF X/U = -0.041 [V]
STS EX DOF Y/V = -0.05 [V]
STS EX DOF Z/W = 0.102 [V]
STS EY DOF Y/V = -0.065 [V]
STS EY DOF Z/W = 1.318 [V]
STS FC DOF X/U = 0.195 [V]
STS FC DOF Y/V = -1.104 [V]
STS FC DOF Z/W = 0.659 [V]
Assessment complete.

Fri Mar 07 10:09:56 2025 INFO: Fill completed in 9min 52secs

Jordan confirmed a good fill curbside.

SUMMARY:  Back To OBSERVING, but got here after going in a few circles.

H1 had a lockloss before the shift, but when I arrived H1 was at NLN, BUT SQZ had issues. 

I opened up the SQZ Overview screen and could see that the SQZ_SHG guardian node was bonkos (so I had this "all node" up the whole time...it was crazy because it was frantically moving through states to get LOCKED, but could not), BUT also I saw.....

1)  DIAG_MAIN

DIAG_MAIN had notifications flashing which said:  "ISS Pump is off. See alog 70050."  So, this is where I immediately switched focus.

2)  Alog70050:  "What To Do If The SQZ ISS Saturates"

Immediately followed the instructions from alog70050 which were pretty straightforward.  Remember:  H1's not Observing, so I jumped on the alog instructions and wanted to get back to Observing ASAP.)  I took the opo_grTrans_setpoint_uW from 80 to 50, and tried to get SQZ back to FDS, but no go (SQZ Manager stuck....and SQZ_SHG still bonkos!).

At this point, I saw that there were several other sub-entries with updated instructions and notes.  So I went through them and took opo_grTrans_setpoint_uW to 60 (no FDS + SQZ_SHG still crazy), and finally set opo_grTrans_setpoint_uW = 75 (but still no FDS + SQZ_SHG still crazy).

At this point, I'm assuming DIAG_SDF sent me on a wild goose chase.  Soooooo, I focused on the erratic SQZ_SHG......

3)  Alog search:  "SQZ_SHG"   --->   H1:SQZ-SHG_TEC_SETTEMP Taken to 33.9

This did the trick!  And this search took me to early Feb2025 alogs from (1) RyanS alog82599 which sounded what I had and then (2) Ibrahim's alog82581 which laid out instructions for what to do for adjusting the SHG TEC Set Temperature (went from 33.7 to 33.9; see attachment #1).  AND---during these adjustments the infamous SQZ_SHG finally LOCKED!!

After this it was easy and straightforward taking the SQZ Manager to FDS and get H1 back to Observing.

NOTE:  I wanted to see the last time this Set Temperature was adjusted and it was Feb 17, 2025.  Doing an alog search on just "SHG" + tag: SQZ took me to when it was last adjusted:  By ME!  During an OWL wake-up call, I adjusted this set point from ~35.1 to 33.7 on 02172025 at 1521utc/72amPST (see attachment #2).

The only SDF to ACCEPT was the H1:SQZ-SHG_TEC_SETTEMP  = 33.7 (see attachment #3).  BUT:  Remember other changes I made (when I erroneously thought I had to adjust the OPO TEC TEMP which are not in SDF:

• opo_grTrans_setpoint_uW = 75  (was 80)
• H1:SQZ-OPO_TEC_SETTEMP = 30.937  (was 30.941)

Hindsight is 20/20, but if I addressed the "bonkos SQZ_SHG" via instructions from an alog search first, I would have saved some time!  :)

TITLE: 03/07 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 4mph Gusts, 2mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.22 μm/s
QUICK SUMMARY:

H1's just made it to NLN .after a 7.75hr lock overnight (lockloss), but has a SQZ ISS Pump Off issue.  microseism are low and winds are as well. 

TITLE: 03/07 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR:  ->Ryan S.<-
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 14mph Gusts, 8mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.20 μm/s
SHIFT SUMMARY:
H1 was locked for 7 Hours and 17 minutes.
Until a sudden and Unknown lockloss struck at 5:24 UTC, Screenshots of lockloss ndscopes attached.

I took the last half hour of my shift to run an Initial_alignment before the start of Ryans Shift.
H1 is currently just past at CARM_TO_TR.

LOG:                                                                                                                                                                                                                                                                                                                                                         

BRS Dift Trends --Monthly FAMIS 26452

BRSs are not trending beyond their red thresh holds.

I assembled the 45MHz WFS unit in the optics lab. Assembly drawing: D1102002.

BOM:

• 1x Pre-assembled WFS body (D1102004 s/n016 Main Body, sealed & scribed as "S1300637" according to Corey's email)
• 1x Alumina spacer (D1102007)
• 1x Baseplate (D1102003)
• 1x Q3000 QPD
• 1x QPD hood (D1102006)
• 2x SHCS 1/4-20 X .75" 18-8 VENTED for the baseplate
• 2x 1/4" PEEK washer (D1102010) for the baseplate
• 4x SHCS 4-40 X 3/16" 18-8 Vented for the QPD hood (spec is BSHCS but SHCS works fine)

I confirmed that the baseplate and the WFS  body are electrically isolated from each other.

There were many black spots on the WFS body (2nd pic) as well as the aluminum foil used for wrapping (3rd pic). It seems that this is a result of rubbing of aluminum against aluminum. I cannot wipe it off but this should be aluminum powder and not some organic material.

QPD orientation is such that the tab on the can is at 1:30 o'clock position seen from the  front (4th pic). You cannot tell it from the picture but there's a hole punched to the side of the can.

Clean SMP - dirty SMA cables are in a bag inside the other clean room in the optics lab. DB25 interface cable is being made (or was made?) by Fil.

TITLE: 03/07 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 144Mpc
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 21mph Gusts, 16mph 3min avg
    Primary useism: 0.06 μm/s
    Secondary useism: 0.25 μm/s
QUICK SUMMARY:

H1 has been locked and Observing for 2 hours and 23 minutes.
All systems are running well, though the range seems a bit low.

TITLE: 03/07 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 146Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY: Currently Observing at 147 Mpc and have been Locked for 2.5 hours. Relocking after the lockloss during the calibration measurements was fully automatic and went relatively smoothly.
LOG:

20:35UTC Lockloss during calibration measurements

22:07 NOMINAL_LOW_NOISE
22:10 Observing

23:25 Three military jet planes flew overhead at a very low altitude (tagging Detchar)                                                                                                                                                                                                                                

I found evidence of possible scattered light while looking at some data from a lock yesterday. Attached is a whitened spectrogram of 30 minutes of data starting at GPS 1425273749. It looks like the peaks are around 28, 38, and 48 Hz, but they are broad and it's hard to tell the exact frequency and spacing. Sheila thinks this may have appeared after Tuesday maintenance. Tagging detchar request so some tests can be run to help us track down the source!

I ran each chilled water pump at the Mid Stations in order to exercise their seals and bearings since these pumps are currently off for the season. This will cause the temperature trending of the loop water to show an decrease for a brief period. The Mid Stations chillers are currently shut down and will remain off until late Spring. 

I'm looking again at the OSEM estimator we want to try on PR3 - see https://dcc.ligo.org/LIGO-G2402303 for description of that idea.

We want to make a yaw estimator, because that should be the easiest one for which we have a hope of seeing some difference (vertical is probably easier, but you can't measure it). One thing which makes this hard is that the cross coupling from L drive to Y readout is large.

But - a quick comparison (first figure) shows that the L to Y coupling (yellow) does not match the Y to L coupling (purple). If this were a drive from the OSEMs, then this should match. This is actuatually a drive from the ISI, so it is not actually reciprocal - but the ideas are still relevant. For an OSEM drive - we know that mechanical systems are reciprocal, so, to the extent that yellow doesn't match purple, this coupling can not be in the mechanics.

Never-the-less, the similarity of the Length to Length and the Length to Yaw indicates that there is likely a great deal of cross-coupling in the OSEM sensors. We see that the Y response shows a bunch of the L resonances (L to L is the red TF); you drive L, and you see L in the Y signal. This smells of a coupling where the Y sensors see L motion. This is quite plausible if the two L OSEMs on the top mass are not calibrated correctly - because they are very close together, even a small scale-factor error will result in pretty big Y response to L motion.

Next - I did a quick fit (figure 2). I took the Y<-L TF (yellow, measured back in LHO alog 80863) and fit the L<-L TF to it (red), and then subtracted the L<-L component. The fit coefficient which gives the smallest response at the 1.59 Hz peak is about -0.85 rad/meter. 

In figure 3, you can see the result in green, which is generally much better. The big peak at 1.59 Hz is much smaller, and the peak at 0.64 is reduced. There is more from the peak at 0.75 (this is related to pitch. Why should the Yaw osems see Pitch motion? maybe transverse motion of the little flags? I don't know, and it's going to be a headache).

The improved Y<-L (green) and the original L<-Y (purple) still don't match, even though they are much closer than the original yellow/purple pair. Hence there is more which could be gained by someone with more cleverness and time than I have right now.

figure 4 - I've plotted just the Y<-Y and Y<-L improved.

Note - The units are wrong - the drive units are all meters or radians not forces and torques, and we know, because of the d-offset in the mounting of the top wires from the suspoint to the top mass, that a L drive of the ISI has first order L and P forces and torques on the top mass. I still need to calculate how much pitch motion we expect to see in the yaw reponse for the mode at 0.75 Hz.

In the meantime - this argues that the yaw motion of PR3 could be reduced quite a bit with a simple update to the SUS large triple model, I suggest a matrix similar to the CPS align in the ISI. I happen to have the PR3 model open right now because I'm trying to add the OSEM estimator parts to it. Look for an ECR in a day or two...

This is run from the code {SUS_SVN}/HLTS/Common/MatlabTools/plotHLTS_ISI_dtttfs_M1_remove_xcouple'

-Brian