Differences between revisions 349 and 351 (spanning 2 versions)
Revision 349 as of 2018-11-24 12:30:31
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Editor: MarkBarton
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Revision 351 as of 2018-12-01 20:05:47
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Editor: MarkBarton
Comment:
Deletions are marked like this. Additions are marked like this.
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==== Report for week of 11/12 ==== ==== Report for week of 11/19 ====
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  * Kozu-kun noticed the BS OL was out of range, and Fabian and Fujii-kun investigated. It turns out that the temperature has risen by over 2°C, so all the GAS filters have sagged and several stages are touching. Miyoki-san and Furuta-san are looking at what can be done.   * 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.
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  * We did the vertical height survey and found that as with SR2 and SR3, the chain is longer than the CAD, this time by ≈7 mm, and again mostly between the SF and BF.
  * The final SRM small glass mirror became available, so we had Hirose-san ship it to us so we can install it while the suspension is still on the assembly frame. Hirata-san ordered shims to make up the new recommended thickness of 1.4 mm and a micrometer to check the combination, which should arrive on Monday 11/26.
  * 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.
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  *
 
  * 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.
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==== Plan for week of 11/19 ====
 * Friday 11/23 is Labor Thanksgiving Day.
 * Mark, Enzo and Fabian at Kamioka Mon-Thu.
 * Hirata-san at Kamioka Tue-Thu (Mitaka on Mon for Engineering Promotion Office meeting).
===== SRM =====
 * Go/no-go test of all electronics items, especially SF/... section.
 * Finish vertical height check and adjust SF trim mass as required.
 * Unlock IP and center roughly.
 * Check/adjust alignment of SS.
 * Calibrate IP LVDTs.
 * Add arc weights and geophones.
 * Improve centering/tuning of IP and SS alignment.
 * Disconnect cables at feedthroughs, lock suspension.
 * Crane into tank.
===== SR2 =====
 * Assist MIF team with pico cables and LBB breadboard ballast.
 * Install SR2 OL pillar and shelf (with AOL supervision)?

==== Plan for week of 11/26 ====
 * Move SRM in-air cables over to tank.
 * Remove First Contact.
 * Unlock and align SRM.
 * Hook and roughly ballast LBB.
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==== Vacation/Event Info ====
 * Hirata-san at Mitaka, Mon 11/19 (Engineering Promotion Office meeting).
==== 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.

Scraps of text for incorporation in the VIS Meeting Minutes

KAGRA/Subgroups/VIS/MeetingNAOJ

Type B (Mark)

Report for week of 11/19

  • BS
    • 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.
  • SRM
    • 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

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.

KAGRA/Subgroups/VIS/TypeB/Minutes (last edited 2022-04-22 13:34:51 by fabian.arellano)