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| ==== Report for week of 10/29 ==== | ==== 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. |
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| * Enzo realized that he could cover the next round of needed cables (all except geophones) with more cable soldering and did another batch. Because Yamamoto-san's lab was running low on isopropanol, Hirata-san washed them with ethanol at Mozumi. * Enzo worked out the optimum output resistance for the LPCDs to substitute for HPCDs with the horizontal IM OSEMs. The value was quite close to that already chosen for modified LPCDs by the cryogenic group, so we're going to standardize on 680 Ω. The modified LPCDs will have to be operated with the internal watchdog disabled for now because it was hard-wired to 2 mA. * Fabian finished adding the TM OSEM cables out to the rack and tested them. * We ran DC power and network to the second SRM stepper driver. We still need to get one more DC power cable to replace one we borrowed from SR3. We added the remaining steppers to the Python driver and MEDM screen. * We reconfigured the top of the assembly frame in preparation for the PI (removing crossbars and moving jacks down). * Hirata-san put the magnets on the SF damper and we hooked it to the PI, craned the PI into the assembly frame and joined it to the security structure. * We installed the F0-SF rod and flying saucer and suspended the SF/... section. We had plenty of spare load capacity, so we changed the CuBe spring to a weaker one and put 2.3 kg of ballast on the SF cap. This leaves 1.2 kg reserve for cables and an F0 yaw stepper mechanism. * We reduced the trim mass on the BF to compensate for the mass of the TM OSEM cables. * We measured all the bounce frequencies. * Hirata-san put magnets on the LBB damper magnet ring, put the pieces into the tank and assembled them into a sandwich ready for craning. He also did the fixed ring on the ceiling of the tank. * Fabian noticed that the DSub9 connectors on the PTFE cables are highly magnetic and need to be kept away from the magnets on the SF damper. This |
* 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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| * Hirata-san unclamped the LBB damper rings and suspended the LBB. It still needs ballast mass and is currently sitting high, with the blades at their upper stops. |
* 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 11/11 ==== * Mark, Enzo, Hirata-san and Fabian at Kamioka Mon-Fri. ===== SRM ===== * Main sequence * Cable/test IP LVDTs. * Cable/test IP FRs. * Unlock IP and center roughly. * Calibrate IP LVDTs. * Check/adjust alignment of SS. * Add arc weights and geophones (or extra mass equivalent to geophones). * Cable/test geophones. * Improve centering/tuning of IP and SS alignment. * LBB * Crane LBB damper ring sandwich to top of lower section of tank. * Set tank jacks to nominal height. |
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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 ===== * Unlock IP and center roughly. * Calibrate IP LVDTs. * Check/adjust alignment of SS. * Add arc weights and geophones (or extra mass equivalent to geophones). * Cable/test geophones. * Improve centering/tuning of IP and SS alignment. * Crane into tank. ==== Plan for week of 11/26 ==== * Move SRM in-air cables over to tank. * Unlock and align SRM. |
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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.