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| ==== Past week report ==== At Kamioka (Mark, Fabian, Enzo, Hirata-san): |
==== Report for week of 1/15 ==== * We set up the QPD for the OL, initialized the OL and TM sections of the RTM, and did TFs from the TM OSEMs to the OL. * Initially we had no coherence, but we debugged issues with the watchdog, LPCD, and DAC board and then got good TFs. * We lifted the IM/RM/SR with the load gauge adapter and checked the weight, which was close to the mass budget. * We installed the section of the AF above the IM, and the BF cross bars and jacks, and craned in the BF. * We installed the BF-IRM rods, IRM, BF-IM rod, flying saucer and the cable clamps on the bottom of the BF. * We hooked the IM section, but found it was heavy by several hundred grams. We also noticed the BF keystone had a noticeable tilt of about 1.2 mm (high on the +X side). * We removed 738 g of trim mass and found that load rose and sat about 2 mm high. So the discrepancy is of order 500-600 g. * Shoda-san, Enzo and Kozu-kun made and characterized a batch of OSEMs. * Hirata-san finished drawings for the improved BS PI yaw/vertical adjustment, placed orders for damping ring receptacles and other items, and prepared the second SR BF in case we needed to swap it in. ==== Plan for week of 1/22 ==== * Fix or swap BF. * Route selected cables to flange. * Test IM picos and BF yaw pico. |
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| * Inspected LLB in tank - in a good position, but not very clean - apparent water spots and dirt. * Found the geophone adapter plates. * Retested SF FR stepper - still good. * Finally got SF LVDT working: * Found a short in the primary coil due to Al foil used for mechanical reinforcement at vacuum feedthrough connection. * Did a full calibration and found that linear range was too small (0.75 mm!) and did not cover nominal keystone height. * Decreased gain to increase linear range. * Adjusted the height of the yoke and secondary coil unit to center the linear region around the nominal keystone height. * Implemented velocity damping. * Found all parts for the LBB and damper rings. * Cu segments and some other parts were very dirty - wiped carefully for now, but should be properly cleaned before final install. * Outrigger parts for LBB have M16 thread cut directly into Al but should have had M16 helicoils. This is a galling risk with Ag-coated rod receptacles. Hirata-san organized rework. * Some special lock nuts are in short supply and are being borrowed from supply at ATC for next batch of BFs. * Made remaining two geophone in-air descrambler cables (total three). * Installed a thermometer supplied by Kokeyama-san on the tower around the BS tank. * Prepared the SF damper. * Designed a pattern of magnets for the two-segment arrangement of SF damper and laid it out on the magnet ring with the template. * Moved the Cu segments on SF cap by 30° (the cap had not been in the right position earlier). * Reinstalled PI: * Raised the PI with the crane and hooked the SF damper ring. Some of the rods did not fit the receptacles due to tolerance issue, but by going through a large number of rods and receptacles, we found three working sets. * Craned the PI onto the frame and suspended the SF/... section, this time with the hex cable clamp on the F0-SF rod. * Tensioned the PI yaw return spring, installed (but did not cable) the yaw stepper and adjusted the yaw of the SF/... section. We worry the return spring is not stiff enough. * Installed (but did not cable) the geophones. * Recentered the IP. The extra weight from the geophones (≈42 kg) and SF damper ring (≈17 kg) had brought the IP to near the point of instability, so we removed one arc weight (≈17 kg) and rearranged the other two in the top row to be symmetrical. * Added ballast to set the height of the F0 keystone. We now have about 6 kg in hand (due to removing one of the Cu segments for the SF damper). This should be enough margin for cables, temperature fluctuations etc. |
==== Plan for week of 1/29 ==== * Enzo at Mitaka 1/29 and most of 1/30, then vacation. * Kozu-kun away. * All others at Kamioka. * Build IRM around IM. * Cable/test/adjust IM OSEMs. * Time permitting, do TFs from IM OSEMs to themselves and to optical sensor. |
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| ==== Plan for coming weeks ==== For more detail, see [[KAGRA/Subgroups/VIS/TypeB/ToDo]]. Weeks of 5/22, 5/29: * Retest SF stepper every day, to see if problems recur. * Find/install geophone adapter plates or improvise replacement. * Reinstall PI, this time with rods and damper ring. * Reinstall PI-SF rod, this time with hex cable clamp. * Cable/test PI geophones LVDTs and steppers. * Reinstall LBB blade units. |
==== Vacation Info ==== * Enzo 1/30-2/19 (at Mitaka 1/29, part of 1/30) * Kozu-kun 1/29-2/2 |
Scraps of text for incorporation in the VIS Meeting Minutes
KAGRA/Subgroups/VIS/MeetingNAOJ
Type B (Mark)
Report for week of 1/15
- We set up the QPD for the OL, initialized the OL and TM sections of the RTM, and did TFs from the TM OSEMs to the OL.
- Initially we had no coherence, but we debugged issues with the watchdog, LPCD, and DAC board and then got good TFs.
- We lifted the IM/RM/SR with the load gauge adapter and checked the weight, which was close to the mass budget.
- We installed the section of the AF above the IM, and the BF cross bars and jacks, and craned in the BF.
- We installed the BF-IRM rods, IRM, BF-IM rod, flying saucer and the cable clamps on the bottom of the BF.
- We hooked the IM section, but found it was heavy by several hundred grams. We also noticed the BF keystone had a noticeable tilt of about 1.2 mm (high on the +X side).
- We removed 738 g of trim mass and found that load rose and sat about 2 mm high. So the discrepancy is of order 500-600 g.
- Shoda-san, Enzo and Kozu-kun made and characterized a batch of OSEMs.
- Hirata-san finished drawings for the improved BS PI yaw/vertical adjustment, placed orders for damping ring receptacles and other items, and prepared the second SR BF in case we needed to swap it in.
Plan for week of 1/22
- Fix or swap BF.
- Route selected cables to flange.
- Test IM picos and BF yaw pico.
Plan for week of 1/29
- Enzo at Mitaka 1/29 and most of 1/30, then vacation.
- Kozu-kun away.
- All others at Kamioka.
- Build IRM around IM.
- Cable/test/adjust IM OSEMs.
- Time permitting, do TFs from IM OSEMs to themselves and to optical sensor.
Vacation Info
- Enzo 1/30-2/19 (at Mitaka 1/29, part of 1/30)
- Kozu-kun 1/29-2/2