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| ==== Report for week of 11/19 ==== | ==== Report for the week of 3/18 ==== |
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| * Fabian did some debugging on the BS and found that the calibration for the F0 LVDT was off due to an Excel error, and that the sag wasn't quite the 7 mm originally observed, but still enough to cause the suspension to touch down. Enzo tried applying LVDT actuation at the GAS filters and got it to lift off far enough to get sensible TFs, but the required BF offset was enough to put the IM OSEMs at the very edge of their usable range, so this is not a good long-term solution. We can probably raise the F0 keystone during the vent by removing mass and/or installing an auxiliary spring, which will then allow us to return the BF keystone to nominal height. * While working on the BS, Enzo noticed that one of the stepper drivers was not responding. It turned out to be water damaged from the rain issues earlier in the year. Enzo and Fujii-kun opened the rest of the BS chassises on the second floor but they seem to be OK. Tanaka-san had made a third driver chassis as a spare, so we reserved that and will install it in the week of 12/10. |
* Terrence notice that one of the IP LVDTs was not working. We traced it to an unplugged cable, plugged it back in and screwed it together to prevent a recurrence. * Simon helped us rebuild the damaged LEN OL QPD stage and Terrence reinstalled it. We removed a C-clamp that we had been using to immobilize the breadboard because it interfered with the QPD stage, and replaced it with a more elegant solution using a dog clamp underneath. * We noticed that the BS IP had fallen over in +L at some time shortly before Nakano-san aligned the optic on 3/18. Terrence tried to recenter it but it was unstable. We decided to remove the tank lid one more time and remove some arc weights. The IP frequency had been 39 mHz the last time it was measurable, and we increased it to a much-safer 80 mHz by removing 9 kg. We believe we were able to recover Nakano-san's alignment fairly closely. * Terrence then recalibrated and diagonalized both the TILT and LEN OL. * SR2 * Terrence recalibrated the OL. * SR3 * Mark pulled out unused cables leading into the SR3 cleanbooth. |
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| * The SRM-W optic arrived and we installed it in place of the SRM-M in the metal mass, taking care to use 1.4 mm shims as recommended by Hirose-san. The weight of the new assembly was within 1 g of the old and did not disturb the height of the payload. There was a very small change in pitch which we corrected with the IM picos. * We installed the shelf for the OL receiver. * We added the arc weights and geophones and went through several rounds of improving the centering of the IP and then realigning the security structure back to vertical. * We calibrated the F0 LVDT, and checked the F0 and IP actuation signs. * We adjusted the SF trim masses to set the SF pitch and roll, did an inventory of the trim mass and set the damper gap. * We did a final alignment of the whole chain and left the suspension ready for TFs during the f2f week. There is only a few hours of work left before we can install and we hope to do that on Monday 12/10. * SR2 * Enzo replaced the geophones and cables that had been borrowed for calibration and did several rounds of optimization of the IP frequency. He got as low as 46 mHz but with poor Q and so backed off a bit to 55 mHz and may back off a tiny bit more. * I derived updated IP matrices for the BS and SR, with more precise geometry data provided by Hirata-san, and published them as T1707205 and T1807663. * I created a CENTERING screen for the IP, with large panel meters for the LVDT signals and the derived L, T and Y signals. * Enzo confirmed that the fancy stepper control screen created by Shoda-san worked. * We installed a modified LPCD as IM-V for testing. * SR3 * We moved HPCDs from BS and SR2 to replace the ones that had been stolen from SR3, so as to create a working suspension with an OL for Kozu-kun. ==== To-Do Lists, Schedule ==== * [[KAGRA/Subgroups/VIS/TypeB/ToDoBS]] * [[KAGRA/Subgroups/VIS/TypeB/ToDoSR]] * [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7779|JGW-L1807779 Type B Schedule (SR)]] |
* Terrence set up the SRM Guardian. * Etc/All * Mark did an audit of the OL whitening/dewhitening system and fixed a bunch of problems: the SRM chassis was the wrong type, with no actual whitening card; SR2 and SRM needed whitening filters turned on; BS LEN needed the dewhitening turned on; SR2, SR3 and SRM needed dewhitening filters installed and turned on; SRM needed more gain. * Terrence weeded out a minor error from his OL diagonalization scheme and got L, T and Y independent at the 1% level for SR2 and SRM. He will do SR3 next. * Fabian measured the gain resistor values and other settings of the LVDT drivers, in case a card or chassis fails and we have to approximate the original state without the chance to recalibrate from scratch. * Fabian monitored the pumpdown. |
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| ==== Plan for week of 3/25 ==== * Mark, Fabian, Terrence at Kamioka Mon-Thu. * Assist with alignment. * Work on Type B paper. * Tidy up. * Throw out foil and other garbage. * Gather and clean tools. * Gather and organize unused parts and fasteners. * Return all unused cables to tent. * Tidy up cables in rear of SR2 rack. |
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| ==== Plan for week of 12/3 ==== * f2f Meeting at NAOJ - no Kamioka work. ==== Plan for week of 12/10 ==== * Crane SRM into tank. * Install new F0 yaw mechanisms on SRs. * Remove First Contact from SRM, unlock and realign. * Move SRM in-air cables over. |
==== Vacation/Travel Info ==== * Enzo's final vacation till 3/29. * Terrence's last day for now, 3/29. * Mark compensation day for 3/21: 3/29. * Type B going-away party for Terrence/Enzo, 3/29 in Tokyo. * Terrence's next visit from 4/18. * Fabian's vacation 4/26 to 5/10. * Mark's final day ≈6/28 (TBD). |
Scraps of text for incorporation in the VIS Meeting Minutes
KAGRA/Subgroups/VIS/MeetingNAOJ
Type B (Mark)
Report for the week of 3/18
- BS
- Terrence notice that one of the IP LVDTs was not working. We traced it to an unplugged cable, plugged it back in and screwed it together to prevent a recurrence.
- Simon helped us rebuild the damaged LEN OL QPD stage and Terrence reinstalled it. We removed a C-clamp that we had been using to immobilize the breadboard because it interfered with the QPD stage, and replaced it with a more elegant solution using a dog clamp underneath.
- We noticed that the BS IP had fallen over in +L at some time shortly before Nakano-san aligned the optic on 3/18. Terrence tried to recenter it but it was unstable. We decided to remove the tank lid one more time and remove some arc weights. The IP frequency had been 39 mHz the last time it was measurable, and we increased it to a much-safer 80 mHz by removing 9 kg. We believe we were able to recover Nakano-san's alignment fairly closely.
- Terrence then recalibrated and diagonalized both the TILT and LEN OL.
- SR2
- Terrence recalibrated the OL.
- SR3
- Mark pulled out unused cables leading into the SR3 cleanbooth.
- SRM
- Terrence set up the SRM Guardian.
- Etc/All
- Mark did an audit of the OL whitening/dewhitening system and fixed a bunch of problems: the SRM chassis was the wrong type, with no actual whitening card; SR2 and SRM needed whitening filters turned on; BS LEN needed the dewhitening turned on; SR2, SR3 and SRM needed dewhitening filters installed and turned on; SRM needed more gain.
- Terrence weeded out a minor error from his OL diagonalization scheme and got L, T and Y independent at the 1% level for SR2 and SRM. He will do SR3 next.
- Fabian measured the gain resistor values and other settings of the LVDT drivers, in case a card or chassis fails and we have to approximate the original state without the chance to recalibrate from scratch.
- Fabian monitored the pumpdown.
Plan for week of 3/25
- Mark, Fabian, Terrence at Kamioka Mon-Thu.
- Assist with alignment.
- Work on Type B paper.
- Tidy up.
- Throw out foil and other garbage.
- Gather and clean tools.
- Gather and organize unused parts and fasteners.
- Return all unused cables to tent.
- Tidy up cables in rear of SR2 rack.
Vacation/Travel Info
- Enzo's final vacation till 3/29.
- Terrence's last day for now, 3/29.
- Mark compensation day for 3/21: 3/29.
- Type B going-away party for Terrence/Enzo, 3/29 in Tokyo.
- Terrence's next visit from 4/18.
- Fabian's vacation 4/26 to 5/10.
- Mark's final day ≈6/28 (TBD).