We ended up using pico in HAM3 to bring down green ALS beam as well as IR POP rather than raising the top periscope mirror after confirming that it was safe to do so.
We first confirmed that the X arm and corner alignment were still the same as yesterday. X arm was still locked to 00 green, and when I misaligned PRM the IR flash in H1:LSC-TR_X_IN1 was reaching 0.8 or more.
We convinced ourselves that the alignmernt was reasonable and probably similar to the alignment before the vent, that the ALS beams were pretty high but was still hitting the top periscope mirror before just like ALSX beam is as of now. We discussed the use of the pico in HAM3 (instead of moving the top periscope mirror up) and decided that it's OK to do so as far as the IR beam is far from clipping somewhere in HAM2.
We moved the HAM3 pico for PIT in "Down" direction by 700 counts and the IR beam position looked about right. We moved the pico further down by 1000 counts (that's the total of 1700 counts down from the initial state) and the IR beam missed the bottom of the top periscope mirror but no sign of clipping in HAM2, so we were comfortable to go 1000 counts "UP" and search for an optimum positision. In the end we ended up going back to 700 counts "Down" relative to where we started.
Sheila and Camilla adjusted top and bottom periscope mirror. M10 (dichroich) was also touched up. Steering mirrors for in-air beams were also roughly adjusted, These are M7 (for REFL air), M11 (for green ALS), M13 (for IR ALS beam from the PSL) and M16 (for POP air).
Now we're ready to move ISCT1L in position to confirm that all beams hit the periscope mirrors on the table.
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:
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".