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| ==== Report for week of 7/2 ==== * We double-checked the bounce frequency and it was indeed around 0.5 Hz with the CuBe auxiliary spring installed. * We prepared (but did not yet install) 6 arc weights for tuning the IP. * We unlocked the security structure from the assembly frame, and raised the whole system on the top jacks. We then unlocked the IP and adjusted the leveling so the IP was centered. We then had to loosen two of the poles at the top level of the security structure to make it vertical again, because it turns out that the jack receptacles (which also serve as the IP leg bases) are welded at very uneven depths in the bottom surface of the PI, so the IP and the bottom surface can't be level at once. * We debugged an issue with the height of the payload. It turns out that due to a buildup of errors (especially an extra 3 mm between the SF and BF), the payload is some 5-6 mm low with the F0 keystone at CAD height. Since the frequency is roughly independent of height around 0.5 Hz, we decided to go with a higher F0 keystone. * Enzo and Eleonora routed all the SF/... cables up to the PI. * We found we needed 4.7 kg of extra mass to get the desired keystone height, so we decided to put the third Cu segment (3.3 kg) back on, purely as ballast. * We put some extra small masses on the SF cap to level it. The suspension is now fully ballasted and trimmed except for 1 Promec mass (455 g) standing in for the new PI yaw stepper motor assembly (estimated 330 g) which is yet to arrive. * We took all the SR sat amps back to Mozumi to get new capacitors installed, and grabbed three spares for use while that is being done. * We investigated and documented Tanaka-san's watchdog for the BS, to see if the BIO Converter chassis that it uses could also drive reset lines for stepper motor driver boxes. * Hirata-san and Terrence characterized the last 4 F0 blades. * Hirata-san and Terrence installed blades in the top filter for SR2 and tuned it to 0.5 Hz (with the CuBe auxiliary spring) over three rounds of compression. ==== Plan for week of 7/9 ==== * Mark, Enzo, Hirata-san, Kozu-kun, Terrence at Kamioka Mon-Fri. ===== Main Sequence ===== * Check/restore alignment of payload, especially optic pitch. * Install and cable geophones. * Install arc weights. * Tune IP. * Install, cable PI yaw stepper. * Make three in-air stepper splitter cables for SR2, SR3 and SRM. * Calibrate PI LVDTs and FRs. * Cabling, testing, TFs. ===== F0/LBB Stuff ===== * Finalize PI #1 for SR2; crane into SR2 cleanbooth. * Remove SR3 tank lid, crane LBB rings to top of lower half of the tank, clamp in position. * Set tank jacks to nominal height. * Clear space for PI #2 (SRM) work. ==== Plan for week of 7/16 ==== * Monday 7/16 is Sea Day. * Mark, Enzo, Hirata-san, Kozu-kun, Terrence at Kamioka Tue-Fri. ===== Main Sequence ===== * Lock suspension. * Crane into tank. * Unlock suspension. * Rearrange cables. * Test. ===== F0/LBB Stuff ===== * Install correct IP in PI #2. * Crane PI #2 to second floor. * Rebuild top filter of PI #2. |
==== 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 ==== * 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.