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| Deletions are marked like this. | Additions are marked like this. |
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| At Kamioka (Mark, Fabian, Enzo, Hirata-san): | At Kamioka (Mark, Enzo, Hirata-san, Yoshioka-kun): * We lubricated the stuck screw at the top of the security structure with stuck and were able to remove it. * Enzo disconnected and removed or coiled many in-vac cables at the PI level to free it. * We craned the PI. There was a minor safety incident - see below. * Hirata-san set up the filter service area, and we moved in a BF intended for one of the SRs (BF#3). * Fabian and Hirata-san worked out a method for characterizing a single spring, and Fabian finished characterizing the first one. * We did a big tidy-up and clean-up of the area, especially the corner where we intended to do the gluing. * We set up the BS gluing jigs and applied the glue. We will check the results on Monday. |
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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 7/24 ==== Full team at Kamioka from Mon-Fri, except Hirata-san (Tue-Fri) and Enzo (vacation). * Check results of gluing. * Finish disassembly. * Finish BF rebuild. * Remove LBB rings. * Recheck alignment of assembly frame and centering of optical table. * Install IM, suspend BS and RM. |
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| ==== Plan for coming weeks ==== For more detail, see [[KAGRA/Subgroups/VIS/TypeB/ToDo]]. |
==== Plan for week of 7/31 ==== Full team at Kamioka from Mon-Fri, except Fabian (Mon-Thu) and Enzo (vacation). * Weigh/trim BS/RM/IM. * Bring in rebuilt BF. |
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| 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: Hirata-san: Thu 7/20 through Mon 7/24 Enzo: Sat 7/22 through Sun 8/6 Fabian: Fri 8/4 through Mon 8/21 Mark: TBD Mid-Oct |
Scraps of text for incorporation in the VIS Meeting Minutes
KAGRA/Subgroups/VIS/MeetingNAOJ
Type B (Mark)
Past week report
At Kamioka (Mark, Enzo, Hirata-san, Yoshioka-kun):
- We lubricated the stuck screw at the top of the security structure with stuck and were able to remove it.
- Enzo disconnected and removed or coiled many in-vac cables at the PI level to free it.
- We craned the PI. There was a minor safety incident - see below.
- Hirata-san set up the filter service area, and we moved in a BF intended for one of the SRs (BF#3).
- Fabian and Hirata-san worked out a method for characterizing a single spring, and Fabian finished characterizing the first one.
- We did a big tidy-up and clean-up of the area, especially the corner where we intended to do the gluing.
- We set up the BS gluing jigs and applied the glue. We will check the results on Monday.
Plan for week of 7/24
Full team at Kamioka from Mon-Fri, except Hirata-san (Tue-Fri) and Enzo (vacation).
- Check results of gluing.
- Finish disassembly.
- Finish BF rebuild.
- Remove LBB rings.
- Recheck alignment of assembly frame and centering of optical table.
- Install IM, suspend BS and RM.
Plan for week of 7/31
Full team at Kamioka from Mon-Fri, except Fabian (Mon-Thu) and Enzo (vacation).
- Weigh/trim BS/RM/IM.
- Bring in rebuilt BF.
Vacation Info: Hirata-san: Thu 7/20 through Mon 7/24 Enzo: Sat 7/22 through Sun 8/6 Fabian: Fri 8/4 through Mon 8/21 Mark: TBD Mid-Oct