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Size: 3153
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Size: 3633
Comment:
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| Deletions are marked like this. | Additions are marked like this. |
| Line 7: | Line 7: |
| At Kamioka (Mark, Fabian, Enzo, Perry, Hirata-san): | At Kamioka (Mark, Fabian, Enzo, Hirata-san): |
| Line 9: | Line 9: |
| * We counted the used/broken/unused/need cables for Type B. * Hirata-san and Mark installed blades in three LBB blade units. * Hirata-san checked the LBB blade units to see how badly the blade tips were misaligned. The bases will need to be moved towards the clamp end by 21 mm. It is probably not feasible to turn the screw holes into slots, so an adapter part will need to be designed. * We checked that the new in-vacuum geophone cables that Takahashi-san had got for us were the proper new-style ones. (Thus we will need in-air descrambler cables.) * Shoda-san sent Enzo a document by Joris on the tuning of the LVDTs, so he stated working through it. He also researched the specifications of all the coils (PI and SF as well as BF.) * We found the damper magnets and the template for placing the magnets on the ring for the SF. * Hirata-san installed and wired up the PI yaw stepper. The vertical stepper still needs wiring, and the horizontal stepper wiring needs to be made vacuum-compatible. * We installed safety bars on the ±X side of the assembly frame about 3 m off the floor, so they are at waist height for a person standing on one of the tall ladders. The one on the +X side will be very good for safety where it is, but the one on the -X side will need re-doing: it is too close and not very securely attached because of interference from vacuum pump cabling. * We unlocked the inverted pendulum and experimented with adding weight. It was still stable with 4 layers of arc weights. * We also experimented with getting both the IP centered and the security structure vertical (so that the suspension hang centrally within it). We managed to get it all right with a combination of leveling the PI with the jacks and moving the IP with the fishing rods. * Adjusting the verticality of the SS had left the bottom of it off-center in the assembly frame, so we picked the entire system up with the crane and moved it in +Y and -X a few mm to re-center it. * We started to remove the PI so we could do various adjustments (check the SF LVDT, reconfigure the Cu damper, add the hex cable clamp on the rod and hang the magnet disk for the SF damper) but gave up when the PI-SF jammed in the SF. |
* 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. |
| Line 26: | Line 38: |
| Week of 5/15: * Enzo from Tuesday 5/16 (driving test), rest of team from Monday. * Fix PI-SF rod jamming. * Remove PI and SF cap. * Continue debugging SF LVDT. * Reconfigure Cu damper ring on SF. * Add magnets to upper SF damper ring. * Add cable clamps on the PI (a few places are inaccessible when the PI is on the assembly frame). * Reinstall PI, this time with rods and damper ring. * Reinstall PI-SF rod, this time with hex cable clamp. * Prepare for PR2 bellows removal on 5/15 (move table with tools). * Cable/test PI horizontal LVDTs and steppers. * Install/cable/test geophones. |
Week of 5/29, 6/6: * Cabling: * Route BF/... cabling up past SF to PI. * Route SF cabling up to PI. * Add Type 3 extensions to SF/... cables. * Move vacuum flanges to positions on assembly frame more convenient for next stage (accessible from second floor, one on each corner of frame). * Move in-air cabling to match flange 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. * 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):
- 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.
Week of 5/29, 6/6:
- Cabling:
- Route BF/... cabling up past SF to PI.
- Route SF cabling up to PI.
- Add Type 3 extensions to SF/... cables.
- Move vacuum flanges to positions on assembly frame more convenient for next stage (accessible from second floor, one on each corner of frame).
- Move in-air cabling to match flange 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.
- Crane into tank.