|
Size: 3286
Comment:
|
Size: 2225
Comment:
|
| Deletions are marked like this. | Additions are marked like this. |
| Line 8: | Line 8: |
| * We disconnected the in-vacuum and in-air cabling from the feedthroughs. * We removed crossbars below BF and SF. * We set the SF damper to 4 mm clearance. * We adjusted the jacks to nominal height. * We removed the geophones and PI yaw stepper for craning. * We craned the suspension into the tank, and hooked the LBB Cu ring. * We replaced the geophones etc. * We unlocked all but the IP and adjusted the jacks until the pendulum was centered in the security structure. * We unlocked the IP and adjusted to to center with the jacks and fishing rods. * We craned the vacuum tank lid+ring back on, and then removed just the lid (only). * We unclamped the LBB damper rings and removed the spacers. * We removed the blocks and shims supporting the LBB, inserted the long screw feet and hooked the LBB to the Cu damper ring. * We added 2*31.5 kg of ballast to the LBB, which got the blades to the point where firm pressure would depress the tips. * We reconnected the in-vacuum cabling. In ≈15 places we opted to omit the Type 1 cable and use a F-F gender bender. * We reconnected all but four of the in-air cables. |
|
| Line 9: | Line 24: |
| * 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 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. |
==== Plan for week of 6/26 ==== Mark and Enzo at Kamioka: * Double-check where gender-benders were used. * Finish connecting in-air cabling. * Debug all cabling. * Work with Simon to set up LSOL. Fabian at Mitaka: * Design final ballast masses for IM, BF and SF assuming no BF rebuild (needs to be adaptable). * Check all items for BS flag/prism gluing are available (prisms, flags, jigs, mirror box, glue, scale, mixing tools etc). Hirata-san at Mitaka: * Do new 3D CAD: * BS Test Hang build, with top of tank, full suspension, and LBB damper all reversed. * Final BS build, as above, but with everything BF down rotated back to original. * In-tank version. * On-assembly-frame version. (Adjust jack positions if possible, or leave for Mark to do.) * SR2 on BS assembly frame. (Adjust jack positions if possible, or leave for Mark to do.) |
Scraps of text for incorporation in the VIS Meeting Minutes
KAGRA/Subgroups/VIS/MeetingNAOJ
Type B (Mark)
Past week report
At Kamioka (Mark, Fabian, Enzo, Hirata-san):
- We disconnected the in-vacuum and in-air cabling from the feedthroughs.
- We removed crossbars below BF and SF.
- We set the SF damper to 4 mm clearance.
- We adjusted the jacks to nominal height.
- We removed the geophones and PI yaw stepper for craning.
- We craned the suspension into the tank, and hooked the LBB Cu ring.
- We replaced the geophones etc.
- We unlocked all but the IP and adjusted the jacks until the pendulum was centered in the security structure.
- We unlocked the IP and adjusted to to center with the jacks and fishing rods.
- We craned the vacuum tank lid+ring back on, and then removed just the lid (only).
- We unclamped the LBB damper rings and removed the spacers.
- We removed the blocks and shims supporting the LBB, inserted the long screw feet and hooked the LBB to the Cu damper ring.
- We added 2*31.5 kg of ballast to the LBB, which got the blades to the point where firm pressure would depress the tips.
- We reconnected the in-vacuum cabling. In ≈15 places we opted to omit the Type 1 cable and use a F-F gender bender.
- We reconnected all but four of the in-air cables.
Plan for week of 6/26
Mark and Enzo at Kamioka:
- Double-check where gender-benders were used.
- Finish connecting in-air cabling.
- Debug all cabling.
- Work with Simon to set up LSOL.
Fabian at Mitaka:
- Design final ballast masses for IM, BF and SF assuming no BF rebuild (needs to be adaptable).
- Check all items for BS flag/prism gluing are available (prisms, flags, jigs, mirror box, glue, scale, mixing tools etc).
Hirata-san at Mitaka:
- Do new 3D CAD:
- BS Test Hang build, with top of tank, full suspension, and LBB damper all reversed.
- Final BS build, as above, but with everything BF down rotated back to original.
- In-tank version.
- On-assembly-frame version. (Adjust jack positions if possible, or leave for Mark to do.)
- SR2 on BS assembly frame. (Adjust jack positions if possible, or leave for Mark to do.)