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| * Hirata-san produced a near-final Inventor assembly of the BS on the assembly frame, for use in writing the assembly procedure. * Includes assembly frame modifications suggested by Mirapro, including feet, wheels, lifting eyes, thicker crossbars under BF, IM etc. * Includes final rail system except for interface plate to mirror box. * Includes full PI with ballast masses. * Includes cable clamps. * Includes correct versions of BF and SF. * Includes new BF pushrod parts to work around different placement of blade screws in new version of BF. * Includes cleanbag support bars. * Includes key parts of mirror box (enough to check for interference) - needs more work. * Does not include various invisible duplicate assemblies that had been present due to cut and paste. * After a few more improvements, the new assembly will be sent back to Mirapro. * Got status from Miyakawa-san on electronics - there should be enough of the boxes AEL is supplying. * Cleanbag design was finalized; Aso-san is ordering: [[attachment:160419-ﾁｬﾝﾊﾞｰｶﾊﾞｰⅡ型.pdf]] * Quote for flags and prisms was received, but expensive - may drop rigid flag design. * The mirror box will require only very minor modifications for flags and prisms - Tatsumi-san will arrange immediately. * Fabian worked on understanding Sekiguchi-san's control design to help decide optimum wire thickness. * Mark worked on install procedure and schedule. * Takahashi-san enquired with NIKHEF about oscillator cards for LVDT chassis - lead time would be 3-4 months. * |
=== 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]]. 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. |
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.
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.