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Size: 3286
Comment:
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Size: 2844
Comment:
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| Deletions are marked like this. | Additions are marked like this. |
| Line 9: | Line 9: |
| * 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. |
* Enzo and Fabian routed all the SF/... cabling up past the SF and anchored it to the PI. * Enzo and Fabian moved the vacuum feedthroughs to new positions on the assembly frame corresponding more closely to the positions on the tank. * Hirata-san received the LBB blades back from additional machining, and he and Mark characterized them, and chose the 3 that were most closely matched. The total load capacity is 294 kg, which is rather larger than the 202 kg for the LBB and intermediate ring. * Mark measured all the coil resistances for the LVDTs and steppers on the PI to check everything was wired properly. * Hirata-san received the outrigger plates for the LBB black from additional machining to add helicoils but discovered that they were not M16 fine pitch but M16 regular. He sent them off again to be corrected. * Mark and Hirata-san inspected the vacuum tank and discovered that the top section is on backwards relative to the 3D CAD so that the jacks supporting the tank and the jacks supporting the PI via bellows are interchanged. We decided that, for the test hang, we would put the suspension in with a 135° anticlockwise rotation (instead of a 45° clockwise one). For the final hang, we will build the suspension with the BS/RM section backwards. * Fabian moved the F0 trim mass from on top of the F0 keystone and anchored it to the SF, keeping about 0.5 kg in reserve to allow for the weight of the SF-PI cables. * Enzo, Fabian and Hirata-san rearranged the in-air cabling for the OSEMs to match changes to the in-vacuum cables. |
| Line 38: | Line 21: |
| 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. |
Week of 6/6: * Cabling: * Finish moving in-air cabling to match feedthrough positions. * Cable and test PI vertical LVDT. * Calibrate PI vertical LVDT. * Set yoke on PI vertical LVDT (if necessary). * Cable and test PI yaw stepper. * Cable and test PI vertical stepper. * Cable and test PI horizontal steppers. * Cable and test PI horizontal LVDTs. * Calibrate PI horizontal LVDTs. |
| Line 46: | Line 33: |
| Week of 6/12: * Remove -Y flange cover, replace with cloth cover (or foil). * Prepare LBB. * Wipe LBB. * Loosen or remove LBB hold-down bolts. * Attach LBB outriggers and rod receptacles. * Lay out slings for LBB damper rings. * Prepare LBB Cu ring. * Pass into tank. * Reassemble on top of slings. * Prepare LBB magnet ring. * Assemble temporarily. * Attach magnets with template. * Disassemble. * Pass into tank. * Reassemble on top of Cu ring. * Remove port covers where feedthroughs will go. * Crane into tank. |
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):
- Enzo and Fabian routed all the SF/... cabling up past the SF and anchored it to the PI.
- Enzo and Fabian moved the vacuum feedthroughs to new positions on the assembly frame corresponding more closely to the positions on the tank.
- Hirata-san received the LBB blades back from additional machining, and he and Mark characterized them, and chose the 3 that were most closely matched. The total load capacity is 294 kg, which is rather larger than the 202 kg for the LBB and intermediate ring.
- Mark measured all the coil resistances for the LVDTs and steppers on the PI to check everything was wired properly.
- Hirata-san received the outrigger plates for the LBB black from additional machining to add helicoils but discovered that they were not M16 fine pitch but M16 regular. He sent them off again to be corrected.
- Mark and Hirata-san inspected the vacuum tank and discovered that the top section is on backwards relative to the 3D CAD so that the jacks supporting the tank and the jacks supporting the PI via bellows are interchanged. We decided that, for the test hang, we would put the suspension in with a 135° anticlockwise rotation (instead of a 45° clockwise one). For the final hang, we will build the suspension with the BS/RM section backwards.
- Fabian moved the F0 trim mass from on top of the F0 keystone and anchored it to the SF, keeping about 0.5 kg in reserve to allow for the weight of the SF-PI cables.
- Enzo, Fabian and Hirata-san rearranged the in-air cabling for the OSEMs to match changes to the in-vacuum cables.
Plan for coming weeks
For more detail, see KAGRA/Subgroups/VIS/TypeB/ToDo.
Week of 6/6:
- Cabling:
- Finish moving in-air cabling to match feedthrough positions.
- Cable and test PI vertical LVDT.
- Calibrate PI vertical LVDT.
- Set yoke on PI vertical LVDT (if necessary).
- Cable and test PI yaw stepper.
- Cable and test PI vertical stepper.
- Cable and test PI horizontal steppers.
- Cable and test PI horizontal LVDTs.
- Calibrate PI horizontal LVDTs.
Week of 6/12:
- Remove -Y flange cover, replace with cloth cover (or foil).
- Prepare LBB.
- Wipe LBB.
- Loosen or remove LBB hold-down bolts.
- Attach LBB outriggers and rod receptacles.
- Lay out slings for LBB damper rings.
- Prepare LBB Cu ring.
- Pass into tank.
- Reassemble on top of slings.
- Prepare LBB magnet ring.
- Assemble temporarily.
- Attach magnets with template.
- Disassemble.
- Pass into tank.
- Reassemble on top of Cu ring.
- Remove port covers where feedthroughs will go.
- Crane into tank.