[Shoshana, Michael]

We've managed to get all of the hardware/parts installed in and we've closed up the BRS chamber. We had to add an inch of shims beneath to motor mount in order to get it to fit/align properly, but otherwise there were only minor complications during installation. We've tested the pico-motor and the mass adjuster using the pico-motor driver that we brought from UW and both seem to work fine. 
For in air balancing, we left the new mass adjuster centered to increase range for future adjustments for when the BRS is pumped down and running, and tried to just stick to moving masses that are inaccessible when the BRS chamber is pumped down. We unfortunately reached the maximum range with the internal masses and had to slightly move the manual mass adjustment system (what is currently used to adjust the center of mass) from center, but that might be returned to center after we re-balance it when it's pumped down. Right now the resonance frequency looks to be around ~7mHz (around 130 second period) which is about the same as it was before Mass Adjuster installation, but we'll check again after the chamber has been pumped down.
Tomorrow we'll finish all of the wiring and electronics to hook up the pico-motor to the LIGO system. The plan is to pump down the BRS chamber tomorrow and re-balance and test the pico-motor some more.

The reference pattern has a higher intensity than expected and we aren't sure why. Right now our best guess is that the light source drifted slightly, and we'll look into it more tomorrow.

EPO tag for BRS pics

[Shoshana, Michael]

Pumped down the BRS chamber overnight and started the ion pump this morning and got it down to 1.9e-6 Torr before we left end End-X. We also wired up the picomotor to the LIGO picomotor controller system. It is hooked up to the 7th channel X-direction and we tested it out and were able to hear it spinning for both directions. The BRS's thermal insulation was reapplied the box closed and the temperature sensors and heating plate were all re-attached and plugged back in. The reference beam's intensity has gone down to be closer to normal somehow, so it doesn't seem to be anything to worry about
We might go back to End-Y one more time tomorrow to clean up the wiring and do a final check of the vacuum pressure.
We waited for the temperature to equilibrate a bit before balancing  because we were hoping that as the temperature rises it would drift back to center, but we ended up using the mass adjuster to try and balance it.
It looks like the + - wires for the damping were switched, meaning when the damping was on it would ring up the BRS. Fixed by changing a line in the BRS code[IF H1_ISI_GND_BRS_ETMY_CAPDRIVE>=0] by switching the [>=0] to [<=0] and switching [H1_ISI_GND_BRS_ETMY_CAPOUTL] and [H1_ISI_GND_BRS_ETMY_CAPOUTR], and [H1_ISI_GND_BRS_ETMY_RELAYL] and [H1_ISI_GND_BRS_ETMY_RELAYR]


FROM THE END-X INSTALL:
Coupling/decoupling move: 1.25k steps
Maximum: +-140k steps
Be careful: +-100k steps

NOTE: MOVING PICOMOTOR +(POSITIVE) DIRECTION TRANSLATES TO MOVING THE BRS UP

TOTAL MOVEMENT TODAY:+21k steps

Centered both ETMY and ETMX BRSs.
For ETMX net movement was +2200 steps, for ETMY net movement was -3200 steps.
For ETMX we saw that the DRIFTMON was moved by about ~3.27 counts per step, and ~2.3 counts per step for ETMY

Cleaned everything up for the ETMY BRS and relabeled all the wires. The final reading that we saw for the ion pump was 9.9e-7 Torr (186uA, 6950V) which seems about right. We left some extra mass adjuster parts with Jim just in case. 

Shoshana, Michael

We took tilt subtraction spectra as a final life check of the BRSs. Both BRSs appear to be in good working order and doing their jobs well.

The logic of the REFL diverter has been changed to alternate beam. This required a restart of the slow controls software.

Before lunch, Tyler, Oli and Betsy removed ISCT1 and the VP simulator. 

POP Beam to diodes: 

Jennie and I aligned the POP beam onto the POP X ASC diode (using flashes then single bounce, with 20W in). We needed to adjust the dark offsets (they are about the same size as the 1.5uW single bounced beam), sdfs accepted in safe attached, properly need to be redone and saved once we get to observe. All segments responded to the beam and a flashlight and we centered the beam in pitch and yaw using PM1 (alignment sliders P:100, Y:50).

Elenna and I aligned the POP beam onto the POP A LSC diode (using flashes then single bounce). We checked the POP LSC picomotor was working as expected. Checked beam was centered on the diode by it was centered by going to the middle of the edges of the diode. All segments responded to the beam and a flashlight and we centered the beam in pitch and yaw using PM1, ndscope. Note that we'll want to check this again tommor0w as we need to offload the picomotor in yaw as it doesn't have much range left. 

We couldn't see the didoe reflected beams (using POP flashes, sensitive IR card and IR viewer) so I dead rekon'ed the positions of beam dumps BD1 and BD2, see attached photo. 

Leaving IMC locked with 2W in. 

Still to do: offload POP LSC pico and check alignment, place BD6a, 6b, 7, 9 (couldn't see beams easily tpday at 2W), final checks (see other alog). 

If I do a "sudo lscpi" this command freezes for about 30 seconds, then eventually returns. While it is frozen, the EDC disconnects from h1susb123 EPICS channels.

This is a 8-core W2245 machines with 5 models, so 3 general purpose cores. The IOC disconnect suggests the lscpi command is taking over all 3 cores.

Interestingly h1iopsusb123 is not in a DACKILL state, its DAC drives are non-zero, frozen at their last values (see attached).

The IPC senders have stopped updating, causing IPC receive errors downstream and SEI SWWD trips.

System has been recovered by power cycling the front-end computer, no IO Chassis restart was needed.

Procedure:

• Fence h1susb123 from Dolphin fabric
• Stop all models
• Power down h1susb123, wait a few minutes
• Power h1susb123 back up using IPMI.

"rtcds showcards" sees all the ADC/DAC/BIO cards in the IO Chassis. 

"sudo lscpi" completes immediately, no 30 second freeze.

I have untripped the SWWDs (SUS and SEI) for BSC1,2,3.

I have not ununtripped any user model watchdogs, will hand over to control room for that.

I've brought the BS, ITMX, ITMY suspensions back to Aligned after untripping the user WD. I also untripped the sei for those and watched them go back to nominal. All looks good.

FRS34056

Sun11May2025
LOC TIME HOSTNAME     MODEL/REBOOT
16:52:48 h1susb123    ***REBOOT***
16:55:12 h1susb123    h1iopsusb123
16:55:25 h1susb123    h1susitmy   
16:55:38 h1susb123    h1susbs     
16:55:51 h1susb123    h1susitmx   
16:56:04 h1susb123    h1susitmpi 

I forgot to credit Cyrus Reed who installed these smart power strips and put them onto the network many moons ago.

I've run these three transfer function measurements with settings as follows:

• HAM5 in ISOLATED, although with HEPI locked but the HEPI ISO gain set to 0 to bypass the locked HEPI
• SR3 in ALIGNED
• SR3 DAMP gains all set to -0.1

The measurements can be found in /ligo/svncommon/SusSVN/sus/trunk/HLTS/H1/SR3/Common/Data/as 2025-05-07_0000_H1ISIHAM5_ST1_WhiteNoise_ISO_{X,Y,Z}_0p05to40Hz_calibration.xml. They have been committed to the svn as r12295.

Checking the coherence between each excitation channel (H1:ISI-HAM5_ISO_{X,Y,Z}_EXCMON) and SR3's euler basis DOFs, the coherence between 5 and 10 Hz was good between the following channels:

ISO_X -> DAMP_T

ISO_Y -> DAMP_L

ISO_Z -> DAMP_V, but also pretty good coherence with DAMP_L and DAMP_T
 

I have run the calibration script to get the calibration factors for the SR3 OSEMs. The (multiplicative) factors are:

    LF: 1.3206
    RT: 1.3705
    SD: 1.3806
    T1: 2.4539
    T2: 1.4819
    T3: 1.4125

The factors are calculated by fitting a frequency-independent real factor to the measured uncalibrated transfer functions to fit the modeled one. The fit range is from 5 to 15 Hz. The attached plots show the before and after of the process.

A few observations:

1) As we had seen before, the Left and Right (LF and RT) OSEMs are pretty well matched to one another, which bodes well for our PR3 Yaw OSEM estimator plans.
2) The T1|T2|T3 OSEMs that measure the vertical direction have their orientation flipped respect to the model. I don't think there's a problem, but it is worth pointing out.
3) The T1 OSEM, which is used to distinguish roll is 70% off from T1 and T2. The large factor feels concerning, but it is consistent with other measurements of SR3. See for example 83963, where in the attached .pdf the Vertical to roll coupling is very clean (page 12). And the difference of T1, T2, and T3 can be seen very directly in page 24.

- I think it might be worth revisiting some of these transfer functions after recalibrating just to confirm that we're getting the numbers right.

If we wanted the OSEM measurements to match with the GS13 calibrations between 5-15 Hz, the factors that should be in the OSEM input filters should be:

    T1: 3.627
    T2: 1.396
    T3: 1.345
    LF: 1.719
    RT: 1.490
    SD: 1.781

Since this change will increase the effective gain of the damping loops by a factor of 30% at a minimum, we must compensate by changing the gains for the filter modules in the M1 DAMP filter bank.