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| ==== Report for week of 8/13 ==== * KAGRA was closed Mon/Tue 8/13-14 due to O-Bon. * Enzo and team debugged an issue with height of the SR3 keystone coupling to yaw of the payload as measured by the OL. We suspect a ferromagnetic item on the SF damper, but we're not sure. ==== Report for week of 8/20 ==== ===== SR3 ===== * Hatoya-san and Enzo gathered date for a study of yaw mode Q damping time as a study of damper ring height. ===== SR2 ===== * We continued with cabling work. * We configured the second pico driver and connected it. * We assembled the LBB damper rings in the tank, craned them to near the top and hooked them. While the tank was open we also set the jacks below the mushroom that will support the suspension to nominal height. ===== SRM ===== * We reserved and configured two pico drivers. * We checked the prism gluing and all the jigs came away successfully. * Fabian assembled the RM. * Hirata-san added ballast masses to the IM and we weighed it, as well as the RM and the optic in the mirror box. * We suspended the optic and RM. ==== Report for week of 8/27 ==== ===== SR3 ===== * We did an inventory of arc weights to see if we had enough for SRM and found that we had only enough for a basic allocation for all of type B (172 kg for BS and 103.2 kg per SR) with almost no spare for tuning. * Using SR3, we did a quick study of the IP frequency as a function of the number of arc weights, to see how much more we might need. 3 pairs of small arc weights (10 mm thick, 4.53 kg each) brought the frequency below 0.1 Hz, 4 pairs made it unstable. If SR3 is typical we would need about 27 kg extra per suspension. * After the IP study, we left three pairs of 10 mm arc weights installed on the IP for more investigation with the digital system (instead of a stopwatch). ===== SR2 ===== * We finished routing the in-vacuum cables, and connected everything through to the rack for final testing. * We brought a basic 103.2 kg set of arc weights (3 large (38 mm) and 6 medium (19 mm)) into the SR2 cleanbooth. ===== SRM ===== * Panwei calibrated 6 OSEMs to be used on the IM. * We brought in all the remaining arc weights from the pallet into the SRM cleanbooth, and Hirata-san cleaned up 1 large arc weight and 3 mediums left over from the BS that complete a basic set of 103.2 kg, plus about 5 kg spare. (However 27 kg of these are on loan to SR3.) * We assembled and installed the bottom section of the security structure under the optic and RM. * We set up a new OL for setting the pitch. We found the reflection off the AR surface was much weaker than for SR2 and SR3, but fortunately the HR surface is almost flat (ROC≈300 m) so we were able to use the HR reflection instead. * ''We set the pitch of the SRM and RM and tightened the wire clamps.'' ==== Plan for week of 9/3 ==== * Mark, Enzo, Hirata-san, Fabian, Kozu-kun, Panwei at Kamioka Mon-Fri. * (Mark possible trip to LIGO Hanford - TBD.) ===== SR2 ===== * Crane in SR2. * Move SR2 in-air cables. * Remove First Contact * Unlock and realign payload. ===== SRM ===== * ===== Etc ===== * Prepare for scheduled power outage on 9/10. ==== Plan for week of 9/10 ==== * Monday 9/10 is scheduled power outage. * Mark, Hirata-san, Fabian, Kozu-kun, Panwei at Kamioka Tue-Fri. * Enzo at Kamioka Tue-Thu, then JPS Meeting Fri, then vacation. * Recover from power outage. ==== Plan for week of 9/17 ==== * Monday 9/17 is holiday (Respect for the Aged Day). * Enzo on vacation. * Mark, Hirata-san, Fabian, Kozu-kun, Panwei at Kamioka Tue-Fri. ==== Plan for week of 9/24 ==== * Monday 9/24 is holiday (Autumn Equinox). * Mark, Hirata-san, Fabian, Kozu-kun, Panwei at Kamioka Tue-Fri. ===== SR3 ===== * Hook LBB, add ballast mass. * Tune IP. ===== SR2 ===== * Adjust ballast/trim mass, with reserve for yaw stepper. * Cable/test PI items (LVDTs, steppers, geophones). * Set damper height. * Add arc weights, adjust IP. * Stage LBB damper rings in tank. ===== SRM ===== * Check gluing result - redo if necessary. * Assemble RM. * Add IM ballast masses (we forgot this before). * Get parts from AOL and set up new pitch-setting OL. * Hang metal mass. * Hang RM. |
==== 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. |
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| ==== Vacation Info ==== * Mark: 8/13-16. * Hirata-san: 8/13-17 * Terrence: 8/24-26 f2f, then returns to Hong Kong. * Enzo: 9/14 JPS, 9/15 through 10/8 vacation in Chile. |
==== 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. |
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.