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| ==== Report for week of 6/18 ==== * Mark checked the health of the suspensions after an earthquake on Monday morning. The BS watchdog tripped and there was a few µrad change in the pointing, but otherwise it was fine. SR3 and SR2 were also fine. * Mark, Enzo and Terrence finalized the trim mass on the BF to set the SF keystone height and BF pitch/roll. * They weighed the SF/... section. With no internal trim mass in the SF but with the flying saucer and rod, but with 2 Promec masses for rough balance, it was 255.4 kg, so allowing 1 kg for cables and fine trim mass, we would like a PI load capacity of 256.4 kg. * Hirata-san and Kozu-kun struggled to tune the top filter for SR3 - see klogs 5310, 5324, 5337, xxxx. At first the results were somewhat unrepeatable, with high frequency and low load capacity. This was improved by using a torque wrench (set to 50 N.m) to tighten the blade base clamp screws, retightening the blade tip screws (which had worked loose) and tightening the collar on the end of the shaft of the magic wand. Eventually ... * Enzo and Terrence cabled and tested the SF fishing rod, and reversed the connections on the SF LVDT actuation to bring it to standard polarity. * Mark and Enzo made many improvements to the Type B MEDM screens. * Enzo and Mark measured the BF and SF bounce frequencies (with the other keystone locked). * Enzo replaced a HPCD that seemed to have failed during the bounce test (but had just had a watchdog trip), and then replaced the replacement, which really did fail. It turns out we need to avoid applying more than about 25000 counts of GAS actuation. * Enzo offloaded the BF LVDT actuator with the BF FR to remove the need for a 10000 ct offset. ==== Plan for week of 6/25 ==== * Mark, Enzo, Hirata-san, Terrence at Kamioka Mon-Fri. * Kozu-kun at Kamioka except Thu. * -- * Shutdown Type B controls (as far as possible) in preparation for risk of accidental power outage during electrical work on 6/26. * Add calculated ballast to SF. * Park PI #1 (for SR2) in top of SR3 assembly frame. * Move PI #3 behind SR3. * Move PI #1 to in front of SRM and start rebuild. * Install PI #3 in . * Suspend SF/... section. * Lots of cable routing and testing. ==== Plan for week of 7/2 ==== * Mark, Hirata-san, Terrence at Kamioka Mon-Fri. * Enzo at Kamioka Mon-Wed. * Kozu-kun at Kamioka except Wed. * -- * Lock suspension. * Remove tank lid and raise LBB damper rings. * Crane suspension into tank. |
==== 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 ==== * Kozu-kun: 7/4 Tokyo. * Enzo: 7/5-6 NAOJ Party, Mitaka. * Terrence: 8/24-26 f2f, then returns to Hong Kong. * Enzo: 9/14 JPS, 9/15 through 10/18 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.