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| ==== Report for week of 3/13 ==== At Kamioka (Mark, Fabian, Enzo, Perry, Hirata-san): * We took a full set of TFs with the BF stationary but the IRM, IM, RM and TM all hanging. * We marked peeling or damaged areas on the clean booth floor for Furuta-san. * We installed the SF, measuring its weight in the process. * We found the crossbars supporting the SF jacks were too high to allow the SF ring to sit on the pillars while also being partially supported by the jacks. (This was an issue with the 3D CAD - the model of the NB-01 jack had a lower minimum height than reality.) We lowered the crossbars by 5 mm and put thicker spacers (12 mm instead of 3 mm) on top of the jacks supporting the SF and everything worked well. * We installed newly cleaned L-brackets under the BF and SF. * We installed a new-style cable clamp under the SF. (This was easier with the SF on the security structure, so we had not done it earlier.) * We installed the SF-BF rod and hex cable clamp. * We suspended the BF/IRM/IM/RM/BS section and found it was light, presumably because it had been trimmed according to the Promec measurement of the SF, not Hirata-san's later value. * We added extra ballast mass corresponding to the difference and found the BF section floated at a good height. * We moved trim mass around on the BF until it hung level, and adjusted the IRM and OSEMs until the IRM-IM EQ stops were well-centered and all the OSEMs were centered laterally and mid-range. * We ran 11 extra 20-m in-air cables from the tank towards the rack. (We will need to add 10-m extensions.) * We connected most of the cables to the vacuum flanges with screws and anti-feedthrough adapters. (Some remain to be done.) * We debugged a 900 Hz ringing in the BF LVDT, which turned out to be because the damping was enabled without appropriate filters or gains. * We debugged excess noise in the TM-H3 OSEM, which turned out to be mostly due to a faulty cable. However we worry that some of it may be due to some extensions made of non-vacuum-compatible ribbon cable which we added because the TM-H2 and -H3 OSEM cables are too short. * We installed new security structure parts at the RM level. * We found all the parts for the lower breadboard suspension, including the blades, blade bases, associated cable clamps etc. We also found the jigs for installing the blades. * Fabian finalized the BF ballast mass design and started on the SF. ==== Report for week of 3/21 ==== At Kamioka (Mark, Fabian, Enzo, Perry, Hirata-san): * We took a full set of TFs with the SF stationary but the BF, IRM, IM, RM and TM all hanging. * We also did a TF from BF LVDT actuation and confirmed that it was working. * We got SUMCON running on Perry's computer and worked out how to do cut-down versions of Fabian's full Type-B model corresponding to the various partial configurations we have data for. |
==== 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. |
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| For more detail, see [KAGRA/Subgroups/VIS/TypeB/ToDo]. Next week: * Everyone (Mark, Fabian, Enzo, Perry Hirata-san) at Kamioka, Monday-Friday except for Hirata-san Wednesday-Friday). * Finish SF installation. * Finish BF cabling, hang BF/IRM/IM/RM/BS from SF and confirm weight matches load capacity. * Re-trim BF as necessary. * Get picomotor driver working. Week after next: * Everyone (Mark, Fabian, Enzo, Hirata-san) at Kamioka, Monday-Friday. * Prepare for PI installation. |
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.