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40m Log |
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Tue May 3 21:05:23 2022, yuta, Update, BHD, AS path alignment, removing a lot of green stuff 7x
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Wed May 4 13:09:42 2022, Anchal, Update, BHD, IMC table balanced again, IMC is locking, YARM is locking
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Wed May 4 15:08:59 2022, Tega, Update, BHD, XARM alignment to get flashing
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Wed May 4 18:52:43 2022, Tega, Update, BHD, POP beam too high at POP SM4 on the ITMX chamber
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Thu May 5 14:46:22 2022, Anchal, Update, BHD, POP beam height lowered, POP_SM4 raised
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Thu May 5 17:05:31 2022, Tega, Update, BHD, IMC & X/Y-arm alignment
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Mon May 9 18:43:03 2022, Anchal, Update, BHD, ITMX table layout corrected
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Mon May 9 18:49:05 2022, Tega, Update, BHD, Relocate green TRX and TRY PDs/cams/optics from PSL table to BS table 
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Tue May 10 15:46:38 2022, JC, Update, BHD, Relocate green TRX and TRY components from PSL table to BS table 
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Tue May 10 18:25:43 2022, Paco, Update, BHD, Green Transmission path
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Tue May 10 16:31:14 2022, Tega, Update, BHD, ITMX optlev return beam steered to QPD
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Fri May 6 13:48:34 2022, Anchal, Update, BHD, WFS loop instability fixed
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Thu May 12 19:55:01 2022, Tega, Update, BHD, AS path alignment 
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Thu May 12 20:11:18 2022, Anchal, Update, BHD, BHDBS Output beams steered out to ITMY table
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Thu May 12 20:24:29 2022, yuta, Update, BHD, POX and POY investigation
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Mon May 16 13:22:59 2022, yuta, Update, BHD, REFL and AS paths aligned at AP table 
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Mon May 16 19:14:17 2022, Anchal, Update, BHD, Camera set on AS path and BHDBS output path
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Tue May 17 18:43:38 2022, Anchal, Update, BHD, Placed SRM in ITMY Chamber
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Wed May 18 08:30:29 2022, Paco, Update, BHD, SRM OpLev
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Thu May 19 08:51:40 2022, Paco, Update, BHD, SRM OpLev
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Wed May 18 09:02:52 2022, Anchal, Update, BHD, WFS1 PD centered
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Wed May 18 17:23:15 2022, Anchal, Update, BHD, Placed PRM in BS Chamber
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Thu May 19 18:56:08 2022, yuta, Update, BHD, Current OSEM sensor values with all the suspensions aligned
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Thu May 19 19:05:59 2022, Anchal, Update, BHD, BS Chamber all work finished, BHD path setup
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Fri May 20 20:03:48 2022, Paco, Update, BHD, ITMY chamber work finished - LO and AS overlapped 
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Mon May 23 13:16:59 2022, Paco, Update, BHD, End of vent - checks  
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Tue May 24 15:21:13 2022, Anchal, Update, BHD, Freeswing tests of new SOS started
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Message ID: 16827
Entry time: Tue May 3 21:05:23 2022
Reply to this: 16829
16848
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Author: |
yuta |
Type: |
Update |
Category: |
BHD |
Subject: |
AS path alignment, removing a lot of green stuff |
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[Tega, Yehonathan, Koji, Yuta]
We tried to align AS path this afternoon.
IMC is not aligned now after the work today 
Green mirrors/perisocope in IMC chamber were removed since some of them was clipping the AS beam, and this changed the balance of the IMC stack and thus MC1 and MC3 alignment.
Summary of changes:
ITMY chamber
- Rotated AS2 in roll by 90 deg to have more aperture for the transmission (photo)
- IR beams are now centered on AS1, AS2, AS3 and AS4 (photo, photo)
BS chamber
- Moved ASL towards -X direction for about 1/4 inch
- Installed GRY_SM2 at the nominal position (re-used GR_SM3 from IMC chamber)
IMC chamber
- Removed green optics GR_SM4, GR_SM3, GR_PERI2L (GR_PERI2L is now stored at Xend)
- Removed IFI camera mirrors FIV1, FIV2 (they are now stored at Xend) (photo, photo)
- GR_SM4 mount is now reused as GRY_SM1 (Y2-2037-0 is now mounted instead of previously mounted Y2-LW1-2050-UV-45P/AR), and GRY_SM1 is installed at the nominal position (photo)
- Moved weights to balance the stack
OMC chamber (we don't have OMC in this chamber...)
- We swapped AS5 and AS6 so that the nobs comes in -X direction to have more spacing between AS beam and IMC REFL beam (photo)
- Moved weights to balance the stack
What we did:
1. Misaligned ITMX and use ITMY reflected beam to align AS path
2. Centered the IR beam on AS1 using SR2
3. Centered the IR beam on AS2 and ASL using AS1. AS2 was rotated in roll by 90 deg to have more aperture for the transmisson. 
4. Centered the IR beam on AS3 using AS2 nobs, centered the IR beam on AS4 by rotating AS3 in yaw.
5. "AS beam" (it turned out that what we are looking was actually not the AS beam!! Some stray light) was in +X direction by 1 inch or so at AS5. Moving AS5 to center the beam would clip IMC REFL beam. So we swapped AS5 and AS6 so that the nobs comes in -X direction to have more spacing between AS beam and IMC REFL beam.
6. Balanced OMC chamber stack again using IMC REFL beam as a referece (bring the IMC REFL beam to the reference red circle on the monitor).
7. Tweaked the alignment of TT1 and TT2 to have Yarm flashing to ~0.9 in TRY. 
8. Moved AS5 towards +X by an inch or so to center the "AS beam."
9. Moved ASL towards -X direction for about 1/4 inch and re-centered the beam by AS1 to see if the "AS beam" gets far from IMC REFL at OMC chamber, but the "AS beam" didn't move much.
10. By blocking the beam from ITMY, we found that "AS beam" was not the actual one. 
11. Opened IMC chamber and found that AS beam is blocked by the past optics.
12. Removed old green optics and IFI camera mirrors. GR_SM4 mount and GR_SM3 were reused as mentioned above.
13. Tried to balance IMC chamber stack to recover IMC alignment. We used IMC REFL beam as a reference, but it was hard to completely bring the IMC REFL beam to the reference red circle on the monitor. It is now off by a beam diameter or so. No IMC flashing now. 
Next:
Theoretically, balancing IMC chamber stack would recover all the IFO alignment, but maybe tough. It is maybe easier to align MC1 and MC3 to have IMC locked. Assuming input pointing to IMC is not drifted too much, we should be able to recover Yarm flashing by tweaking TT1 alignment only. However, MC3 SD OSEM is at the edge of the range. We might have to balance the stack more or tweak SD OSEM position. |
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