In 82097 we got some constraint on the circulating power in the arm from the squeezer data set.  I'm working on looking at the data that Camilla took in 83660, and realize that with the higher nonlinear gain the frequency independent squeezing gives us a better constraint on the arm power.

Using known injection losses of 8.2%(google sheet),   and  6% extra HAM7 losses from 83070 gives 13.7% minimum injection losses for squeezing, and our known readout losses are 8.4%.  Based on 16.1dB of anti squeezing (for NLG of 19 as reported by Camilla) and -4.97 dB squeezing, the infered NLG is 18.7 and the total sqz efficiency is 0.694 (with 0 phase noise). This means that in addition to the 6% extra losses measured on the homodyne, we have another 12% unknown squeezer losses.  We can assign those 12.2% losses to either injection losses (unlikely since there isn't much between homodyne pick off point and injection into the OFI), readout losses that also impact the IFO readout, or squeezer readout losses that don't impact the IFO (SQZ to OMC mode matching). 

If the only IFO readout losses are the known losses, the IFO readout efficiency is 91.6%, and we can use the shot noise level without squeezing injected to estimate that the minimum arm power is 310kW.  Using the total squeezer efficiency and the known losses, we can place bounds on the readout efficiency between 80.4% and 91.6%.  The level of shot noise measured without squeezing mostly depends on arm power and readout efficiency, so this maximum readout efficiency gives us a minimum arm power of 310kW (all squeezer losses are injection losses, readout efficiency is 91.6% and arm power is minimum), while the minimum readout efficiency gives us 353kW (all unknown squeezer losses are common to IFO, which probably wouldn't be the case for mode mismatches). 

Ryan C, Rahul

L1BHDM1 which is the suspended configuration of HRTS (HAM Relay Triple Suspension) for O5 is now ready to be shipped to LLO (using ground freight). The suspension (all stages locked with EQ stops, torqued double nuts and tension removed from wires ) has been wrapped in several layers of clean foil/clean cloth and clean bag as shown here.

This shipment is expected to reach LLO sometime at the end of next week (25th April), if it leaves LHO today. The details of the shipment are given below,

Tracking Site Link: https://www.shipdbi.com/ HWB Number for TRK: 139289

FRS ticket - https://services1.ligo-la.caltech.edu/FRS/show_bug.cgi?id=33849

ICS (assembly record) - https://ics.ligo-la.caltech.edu/JIRA/browse/ASSY-D1900449-L1BHDM1

ICS (shipment load) - https://ics.ligo-la.caltech.edu/JIRA/browse/Shipment-13842

This is first of the total six HRTS which will be transported to LLO.

Jim, Tony, Dave:

We restarted h1isiham1 model four times and the DAQ twice:

1. Internal wiring change to model, no DAQ retstart for that but new common part with "missing ADC chans" fix was included which did require a DAQ restart. No issues with DAQ restart other than gds0 needed a second restart.

2. A copy-paste binary parts issue was found, HAM6 parts were included in HAM1. BIO parts were renamed, no DAQ restart was neeed.

3. HAM1 differs from HAM6 in BIO inputs in that it reads 64 input channels instead of just 32. Upper32 channel BIO part was added, which added slow channels, so DAQ restart was required. No issues with DAQ restart other than gds0 second restart.

4. To minimize binary chassis hardware, HAM1 and HAM6 share the first BIO card's binary output chassis, HAM6 uses lower 32 chans, HAM1 uses upper 32 chans. h1isimodel was changed to use BIO-0 U32 for outputs. No DAQ restart was required.

Current BIO hardware as see by models:

Thu Apr 17 10:09:38 2025 INFO: Fill completed in 9min 34secs

Late entry

4-16 (Wednesday) activities:
- The previously received, poorly packaged Inficon gauge has been tested, and found functional. These tests continue, and also the HAM1 vacuum interlock gauge will be installed soon
- The BSC8 Annulus Ion Pump - after some aux cart pumping - is now able to hold the annulus pressure, at the mid- E-6 Torr region
- The rough pumpdown of the corner has started at 16:20, at the OMC turbo station, with a pair of ISP-1000 mobile pumping carts. In 4 hours, ~185 Torr was achieved, which means 1930 l/s effective pumping speed, which well corresponds with the 2000 l/s theoretical speed of the pumps
- The rough pumping still needs to be terminated in the end of the days, and so it was at 20:20
- All the turbo stations have been prepared for the HV pumping at the corner

Closes FAMIS26039 , last checked in alog83802

Most of the HAMs looks more elevated than last time, due to the vent activities.

The BSCs look the same as when they were last checked.

TITLE: 04/17 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, 3mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.20 μm/s
QUICK SUMMARY:
VAC team have been Pumping down the corner station volume for 15 hours now and H0:VAC-LX_Y2_PT180_MOD1_PRESS_TORR channel is reporting that we are below 200 torr in BSC8 chamber.

Expected work today:

• Start Corner vent - STAND DOWN HAM1 in-chamber work THUR and FRI, evaluate pressue on MONDAY, measure dew point
• Fil - HAM1 Out of vac cable runs to chamber
• HAM4-5 Cable tray work - Ken, some Crane usage
• VAC - HAM1 Top flange Gauge work table side - GM?
• EX and EY - ALS work beam profiling ( LASER HAZARD)

For each ADC a user model uses the RCG generates an ADC MEDM showing the raw counts for only those channels the model connects to. In order to make this MEDM more useful, for each channel the RCG attempts to find a named part in the simulink mdl and adds that name to the MEDM.

If the first simulink part found when traversing the model does not have a name (e.g. is a summation, gain, multiplier, etc.) currently the RCG leaves this channel off the MEDM. Future RCG versions will fix this by adding generic ADC names, but in the mean time we are taking the vent RCG upgrade as an opportunity to install named EPICS_OUTPUT parts where needed. Ideally the subsystem authors would give these parts descriptive names, but failing that we will give them generic ADC_x_y type names.

Jim has done this for the ISI HAM models, so when we restarted h1isiham2 and h1isiham5 on monday those models' ADC MEDMs were corrected. The attachment shows the ADC MEDMs for h1isiham2 (full) compared with h1isiham3 (partial).

TITLE: 04/17 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
The Vacuum team has started the Pump Down !
The SPI team has components on the table and are currently in an optomization stage.
I think Jim still has more work to do on HAM1.
 

Joe doing update of installed pydarm code.

At 21:38 UTC the water level sensor for the fire tank was restarted by Eric because it was reading as full but was not.

21:48 UTC the Water tank sensor was restarted to make the Water level sensor read correctly.

LOG:

J. Kissel scribing for S. Koehlenbeck, J. Oberling, R. Short, J. Freed
ECR E2400083
IIET 30642
WP 12453

Another quick summary aLOG at the end of the day, with more details to come:
- With the power in the ALS/SQZ pick-off path to 10 [mW] for beam profiling,
- Installed a two lens system to handle the unexpectedly different beam profile of the ALS/SQZ pick-off path
- Remeasured the resulting mode after the two lens system, and we're happy enough. We're gunna call them SPI-L1 and SPI-L2.
- Installed steering mirrors SPI-M1 and SPI-M2.
- Rotated ALS-HWP2 to increase the s-pol light in the ALS/SQZ/SPI path to return the power transmitted through SPI-BS1 going to the ALS/SQZ fiber collimator back to 50.5 [mW]. This set the SPI path to 186 [mW] with the PMC TRANS measured at 103.5 [W]. The ALS_EXTERNAL PD in transmission of ALS-M9 measured 31 [mW] ***. 
- Installed SPI-HWP1 and SPI-PBS01
- Measured the power at each port of SPI-PBS01, with the intent to optimize the SPI-HWP1 position to yield maximum p-pol transmission through SPI-PBS01.

*** We expect this is lower than the goal of ~45 [mW] (from LHO:83927) because we've not yet re-aligned the ALS/SQZ fiber collimator path after the install of the SPI-BS1, which translates the beam a bit due to the thickness of the beam splitter. We intend to get back to this once we're happy with the SPI path.

Sheila, Oli, Jeff, Erik, Edgard, Brian

While looking at the pointing drift over the course of the vent for SR3, Sheila and I noticed a jump in the DAMP_P_INMON channel before vs after the SR3 model restart that was done yesterday (83906) (attachment1). We looked around trying to trace where the discrepancy started until we finally noticed that the 32 coming out of DITHER P was entering DRIVEALIGN as L (attachment2). This was confirmed as the discrepancy when we trended the DRIVEALIGN_L and DRIVEALIGN_P channels and confirmed that before the model restart, DRIVEALIGN_L was (correctly) 0 and DRIVEALIGN_P was (correctly) 32, but after the model restart they had been swapped (bottom middle of attachment1).

Looking at the 2nd and 3rd Simulink model screenshots that Jeff had uploaded in 83911, we see that the ADDFF block takes in LPY in the wrong order - as FF_P_In, FF_Y_In, FF_L_In, and then sends it back out in the wrong order as well - as PITCH_Out, YAW_Out, LONG_Out.

I've corrected these mistakes (attachment3, attachment4) and recompiled the PR3 and SR3 models, and Erik was available to restart both models for us. Everything looks good now! The discrepencies with DAMP_P_INMON and the Left and Right COILOUTs have been resolved.

Changes in model /opt/rtcds/userapps/trunk/sus/common/models/SIXOSEM_T_STAGE_MASTER_W_EST.mdl committed to svn as r31287.

J. Kissel scribing for S. Koehlenbeck, R. Short, J. Oberling, and J. Freed
ECR E2400083
IIET 30642
WP 12453

During yesterday's initial work installing the SPI pick-off path (LHO:83933), the first optic placed was SPI-BS1, the 80R/20T power beam-splitter that reflects most of the s-pol light towards the new SPI path. The pick-off is to eventually be sent into a SuK fiber collimator (60FC-SF-4-A6.2S-03), so we wanted to validate the beam profile / mode shape of this reflected beam.


The without changing any power in the ALS/SQZ/SPI pick-off path, the power now reflected from newly installed SPI-BS1 measured ~40 [mW] (see LHO:83946). This is too much for the WinCam beam profiler, so they used ALS-HWP2 to rotate the polarization going into ALS-PBS01, and thus reduced the reflected s-pol light in this ALS/SQZ/SPI pick-off path to ~10 [mW]. That necessarily means there's a little more of the ~2 [W] p-pol light transmitted and going toward the HAM1 light pipe, so they placed a temporary beam dump after ALS-M2 so as to not have to think about it.

The they set up a WinCam head on a rail and gathered the beam profile. With the WinCam analysis software on a computer stuck in the PSL, they simply gathered the profile information which I report here: 
# Distance[cm]	Radius[um]   Radius[um]
                   X             Y
    0.0           680.5         717
    17.78         465           504
    25.4          389           428.5
    30.48         346.5         368
    38.1          281.5         300.5

where "X" is parallel to the table, and "Y" is orthogonal to the table. The "0.0" position in this measurement is the "front" of the rail (the right most position as pictured in the attachment), which is Column 159 of the PSL grid. SPI-BS1 has the center of its reflective surface is set in +/- X position in Column 149 (within the existing ALS-PBS01 to ALS-M9 beam line). It's +/- Y position is set to create a reflected beam line along Row 30 of the grid, and the WinCam head and rail are centered in +/- Y on that Row to capture that beam.

Using this profile measurement, we find it to be quite different than expected from when this path was installed circa 2019 (see e.g. LHO:52381, LHO:52292, LHO:51610). Jason shared his mode matching solution from LHO:52292 with us prior to this week, and I've posted it as a comment to that aLOG, see LHO:83957.

We think we can trace the issue down to an error in the as-build drawing for the PSL:
- the whole beam path running in the +/-X direction from ALS-M1 to ALS-M2 is diagrammed to be on row 23 -- however, we find in reality, the path lies on row 25. That's 2 inches more between the (unlabeld) pick-off beam splitter just prior to ALS-M1 and ALS-M1 itself. Easily enough to distort a mode matching simulation.
- Jason confirms that he used the *drawing* to design the lens telescope for this ALS/SQZ fiber distribution pick-off path.

More on this as we work through a lens solution for the SPI path.

As of this entry, we elect to NOT create a new solution for the whole ALS/SQZ fiber distribution pick-off i.e. we *won't* adjust ALS-L1 or ALS-L5 in order to fix the true problem. But, we report what we found in the event that a case is better made to help mode matching and aligning into the ALS/SQZ fiber distribution pick-off easier -- as we have verbal confirmation that it was quite a pain.
For the record the fiber collimator used in the ALS/SQZ distribution pick-off is a Thor Labs F220 APC-1064.

Janos - 9:50, LVEA

The X-manifold is valved out from the main volume both sides, the main turbo is pumping on it.
On the X-manifold I slightly opened up the suspicious blanked-off small Varian gate valve (see photo), to find out if it is opened or closed.
I moved very slowly the hand-actuator, and the pressure spiked up to the E-5s, then it immediately started to go down, now it is already at ~3E-7 (the initial value was ~1E-7).
So, the valve was closed and blanked off, therefore it wasn't stored appropriately, thus at the next opportunity (when the X-manifold will be vented), it will be removed, and blanked off.

Back in August 2023 the damping gains for SR3 were reduced from -1 down(up?) to -0.5 to help with noise in DARM (72130). Since that change, we had never taken a set of transfer functions with the damping loops on with these new gains, so today I took those. The resulting transfer functions don't show too much damping, which is expected.

The data can be found in ../HLTS/H1/SR3/SAGM1/Data/2025-04-15_2000_H1SUSSR3_M1_WhiteNoise_{L,T,V,R,P,Y}_0p01to50Hz.xml, and has been committed to svn as r12228.

The results can be found in ../HLTS/H1/SR3/SAGM1/Results/ as 2025-04-15_2000_H1SUSSR3_M1_ALL_TFs.pdf and 2025-04-15_2000_H1SUSSR3_M1.mat, and have been committed to the svn as r12229.
 

Jason O, Georgia M

ECR 1900246

This week we have been in the PSL installing a new fiber pick-off for the ALS and squeezer lasers. The old pick off is on transmission of the reference cavity while the new one is on the ALS bypass, after the PMC. Peter K started this work a month ago (alog 51610).

We currently have installed a mode matching lens (f=200mm f=150mm) between the beam splitter and the steering mirror, and achieved ~73% ~82% power transmission through the fiber so far.

We think we can get more light through the fiber by tweaking the mode matching lens position. We will need to go back into the PSL again to finish this work and feed the fiber and photodiode cable out to the rack. 

Once the layout is finalised I'll update the psl table layout document (D1300348).

Modifications to the fiber distribution box are also ongoing.