I've added PM1 to HAM1 since posting this.

Went in to monitor the BBSS alignment after pulling this new wire. All alignments were the same as yesterday. I have since covered the BBSS to take TFs, which have been saved as of writing this. Next, the plan is to compare the gold plated wire loop TFs with the non-plated wire loop TFs.

[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). 

EPO tag for pics of laser safety in practice.

Photos attached of the Green X-arm and POP beams on the HAM1 top periscope mirror before the HAM2 pico-ing and after the HAM2 pico-ing in the final position. 

Tyler fork-lifted ISCT1 into position and we correctly set the height. There was some confusion due to a typo by me on the -X-Y corner height measurement that we've now corrected.

PSL ALS and Green ALS Beams:

To get the PSL ALS and green ALS beams through the VP simulator and onto the top periscope mirror, Sheila needed to move both final steering mirrors (M11 and M13) to have the beams more centered on the VP simulator:

• M11 (for green beams) was moved in +X. We had to carefully think about not centering the alignment of this beam on all mirrors as the Y-arm green beam will be ~8mm on the -X side of the X-arm beam. 
• M13 (for the PSL ALS) was moved in -X, ideally we'd have moved it more to further center on the VP but it would have clipped on L2. 

Photos of the final positions attached, on the VP simulator (inner red circle is the location of the actual window),  on the upper periscope mirror, on the lower periscope mirror and on the ALS shutter, we expect to need to do some steering of the UPM to get the final beams better on the LPMs, this will be done once ISCT1 is installed and realigned. 

POP air and REFL air alignment
(Note: At this point, HAM1 drawing https://dcc.ligo.org/D1000313-v19 was not useful for exact placement of the mirrors because, as was reported earlier, POP and REFL beam position coming from HAM2 into HAM1 are different from what the drawing suggests by an inch or so. )

POP air steering mirror (M16) had to be relocated closer to the periscope, otherwise the POP air beam hit the -X edge of the viewport simulator when we tried to center POP air on the periscope mirror on ISCT1. But then the REFL air beam became close to the M16 mirror mount, so we ended up moving M16 MUCH closer to the periscope and the REFL air steering mirror (M7) got further down in -X direction. As a result, two beams now crosses with each other inside the chamber. See the first attachment where the new POP air beam is in orange and the new REFL air path is in cyan. This is for illustration purpose only.

2nd attachment: Overview of the POP and REFL air path in chamber.

3rd and 4th attachment: Detailed location of M16 and M7, respectively.

5th attachment: REFL air beam is comfortably away from the M16 mirror holder.

6th attachment: Beam position on the viewport simulator. Dimmer beam is POP air.

7th and 8th: REFL and POP beam on the top periscope mirror of ISCT1.

This means that the beam diverters WILL have to be relocated and reconfigured.

Just swapping the positions might not work.

I wonder if using one diverter at the edge of the table will catch both beams. (That's not a good idea as we might want to use in-air POP WFS if in-vac one doesn't work well.)

Distance from POP air steering mirror (M16) to the top POP periscope mirror in ISCT1 was: 34 1/4 + 30 1/4  = 64.5"

Distance from REFL air steering mirror (M7) to the top REFL periscope mirror in ISCT1 was: 13 3/4 + 30 + 31.5 = 75.25"

Measurement was done using long-ish ruler, but it wasn't long enough so we had to measure the distance in multiple segments. I'd say that the error bar of this is roughly +-3/4".

First attachment shows the beam right after the viewport, shot by Betsy's cellphone. The beam looked much worse to my eyes on the viewer card.

Anyway, Jason and I found that

1. Nothing was clipping in the PSL room.
2. The beam position on ALS-PBS01 and ALS-HWP2 was OK. Not excellent but OK.
3. But the beam was significantly offset in YAW on ALS-L2 and downstream (2nd attachment).
4. We were able to see two very bright beam spots somewhere inside the beam pipe viewd from the PSL room, though we couldn't tell what that was.

3rd attachment shows ALS-L2 where the beam was offset by about half of the open aperture radius of the lens mount (the lens itself is 1").

We used ALS-M2 and ALS-M3 to recenter the beam on two reference irises. 4th attachment shows ALS-L2 after this adjustment where the beam is more centered. Not perfect but much better.

On the 5th picture the beam shows no sign of clipping but the beam is close to the -Y edge of the baffle hole for the viewport.

Next Jason moved the top periscope mirror to steer the beam to where it's supposed to be in HAM1. The beam looked more centered on the baffle (6th picture).

7th picture: The location of the steering mirror for this beam on HAM1, which was set according to the HAM1 layout drawing.

8th and 9th show the PSL-ALS beam right after it is reflected by the steering mirror, and right before it leaves HAM1. We might have to fine-adjust this.

As Keita notes, before yawing the top periscope mirror he and I checked the 2 ALS alignment irises that sit under the periscope between mirrors IO_ALS_M3 and IO_ALS_M4 (the bottom ALS periscope mirror).  The beam was off on both alignment irises to the -Y side, suggesting a beam shift had occured sometime between the end of the PSL laser upgrade in Jan 2022 and now (the last time I recall looking at this alignment was at the end of the laser upgrade); using an IR viewer Keita looked at the beam on IO_ALS_L2 (the 2nd ALS mode matching lens) and the beam was off-center on the lens as well.  The beam looked decently well aligned (not perfect) along the IO_ALS_M1 to IO_ALS_M2 path, but beyond that it was well off.  It's unclear what casued this shift.  There was the recent SPI pickoff install last month that potentially could have bumped IO_ALS_M2, since they were working in that area, but I don't think that alone would be enough to cause the shift we saw.  The beam needed to be walked in the +Y direction using both IO_ALS_M2 and IO_ALS_M3 to re-center on the alignment irises, but bumping only a single mirror would more than likely have caused an angular shift in the beam and be easily corrected using only the mirror that was bumped.  This defintely was not the case, as we needed both IO_ALS_M2 and IO_ALS_M3 to walk the beam back to the irises.  So as of right now I cannot say what caused this misalignment, it's entirely possible the ALS beam has been misaligned for a while.

As noted above, we used IO_ALS_M2 and IO_ALS_M3 to re-center the ALS beam on the alignment irises, and at this point the beam was no longer clipping when traversing the ALS light pipe.  Back on the HAM1 table, the mirror that directs the ALS beam onto ISCT1 was still too far in the -Y direction for comfort (getting a little to close to the future home of the JAC and its associated optics).  I then went into the enclosure and yawed IO_ALS_M5 (the top ALS periscope mirror) until the mirror in HAM1 was in its as-designed location.  I've attached a picture I took of how the ALS beam now looks when entering the ALS light pipe; it's now a little closer to the +Y edge of the light pipe.  Before adjustment the outside edge of the beam was very roughly 1" or so away from the light pipe edge (did not get a picture of this), now it's very roughly 1/2" or so away from the edge.