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betsy.weaver@LIGO.ORG - posted 16:56, Friday 19 November 2021 - last comment - 17:02, Monday 22 November 2021(60718)

HAM6 alignment work

This afternoon, Keita, Georgia and I worked on realigning the OM path in HAM6 with the OPO beam from HAM7, since it was known that the new OFI shifted the beam there. Upon arrival, we observed the beam to be in it's ~expected new location per E2100382. So we translated and yawed OM1 to point to center of PM2, yawed OM2 to center beam to OM3 and into OMC. Keita adjusted the gold tube baffle behind OM1 and we slid the fast shutter (toaster) back and towards OM1 to catch the new beam position (still needs to be tested). From there we started to see light on various PDs. Keita and Georgia are now working on rastering to see where we are on PDs - will let them expand. Georgia has a set of photos which we'll eventually post here with before/after hardware moves on HAM6. There are more paths to align, but this is ~how far we got today.

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betsy.weaver@LIGO.ORG - 16:59, Friday 19 November 2021 (60719)

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Working with beam transmitting through HAM5 door GV with ZM6 just inside to steer it. Pretty black looking in there.

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georgia.mansell@LIGO.ORG - 17:36, Friday 19 November 2021 (60720)

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Photo dump from HAM6 today:

The beam from the squeezer laser, reflected off a retroreflector (stand in for FC1), propagated through the open viewport in HAM5, though the OFI and transmitted through the septum. Beam is ~30mm from the edge of the +X side of the window.
The beam at OM1 in its O3 position, it’s a few inches off in yaw, and ~3.5mm high from center.
The beam height at OM1 measured on a ruler, it’s ~105mm and it should be 4".
The height of OM1 itself.
The position of OM1 on the HAM6 ISI before moving (1, 2).
The birdseye view OM1 and OM2 positions before.
The OM2 position before (1,2)
The beam position on OM1 after moving it and steering it so the beam is centered on OM2.
The beam position on OM2 after steering and re-angling so the beam is going to the OMC.
The beam position at the entrance to the OMC.
The position of OM1 *after today's alignment*
The position of OM2 *after today's alignment* (see Betsy's alog!)
Birdseye view after today's alignment: we still need to align the path on transmission of OM1 (circled in white), which are the ASC_AS_C QPD, and AS_air camera paths. We still need to align the fast shutter (circled in red) such that the reflection goes into the high power beam dump (circled in green). We still need to align the black glass beam dump (circled in purple) which catches the beam reflected from the AS_air beam diverter (circled in black)
OMC DCPD pre-amplifier box photos for future reference (1, 2)

We tried to raster OM1 and OM2 to get the beam centered on the OMC QPDs. We saw some light but the OPO lock was drifiting and making things confusing. We'll pick this up on Monday.

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