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At Kamioka (Mark, Fabian, Enzo, Hirata-san): | At Kamioka (Mark, Ohishi-san, Fabian, Enzo, Hirata-san, Yoshioka-kun, Kozu-kun): * We disconnected the SF/... section and reinstalled the F0-SF rod with the hex cable clamp attached. * We debugged an issue with the actuation (the real-time model needed rebooting). * We routed all the SF/... cables up to the bottom of the PI, and then to the feedthroughs. * We unlocked the F0 keystone and experimented to find the amount of mass needed on the SF (≈845 g). * We attached the SF trim mass, adjusting it laterally so that the SF was level in pitch and roll. * We corrected some errors on the MEDM screens (some broken links and Take/Restore Safe.snap buttons). * We cabled all the PI items through to the rack and did very basic testing. * We disconnected the security structure from the assembly frame and adjusted the PI till the SS was vertical. * We unlocked the IP and adjusted the PI jacks and FRs till the IP was centered. * We passed the halves of the LBB Cu damping ring (less the Cu) into the chamber and joined them. * We put the magnets on the LBB damper ring using the template. * We locked various combinations of keystones and measured the vertical resonance frequencies of the unlocked filters. * We spent time on getting the geophones working. The original descrambler adapters had gone missing, so Enzo created three new ones. We borrowed a cable to replace one that had broken. The geophone distributor (S1402167) failed (no power on the negative rail), and a replacement borrowed from SR3 (S1605513) kept switching off. |
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* 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 week of 9/13 ==== ==== Plan for week of 9/19 ==== No work Mon 9/18 (敬老の日)<<BR>> Mark, Fabian, Enzo, Ohishi-san, Hirata-san, Yoshioka-kun (Tue, Wed, Thu, Fri), Kozu-kun * Install LBB damper magnet rings in tank. * Remove tank lid. * * Install suspension. |
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==== 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. |
==== Vacation Info ==== Mark: 10/16-24 |
Scraps of text for incorporation in the VIS Meeting Minutes
KAGRA/Subgroups/VIS/MeetingNAOJ
Type B (Mark)
Past week report
At Kamioka (Mark, Ohishi-san, Fabian, Enzo, Hirata-san, Yoshioka-kun, Kozu-kun):
- We disconnected the SF/... section and reinstalled the F0-SF rod with the hex cable clamp attached.
- We debugged an issue with the actuation (the real-time model needed rebooting).
- We routed all the SF/... cables up to the bottom of the PI, and then to the feedthroughs.
- We unlocked the F0 keystone and experimented to find the amount of mass needed on the SF (≈845 g).
- We attached the SF trim mass, adjusting it laterally so that the SF was level in pitch and roll.
- We corrected some errors on the MEDM screens (some broken links and Take/Restore Safe.snap buttons).
- We cabled all the PI items through to the rack and did very basic testing.
- We disconnected the security structure from the assembly frame and adjusted the PI till the SS was vertical.
- We unlocked the IP and adjusted the PI jacks and FRs till the IP was centered.
- We passed the halves of the LBB Cu damping ring (less the Cu) into the chamber and joined them.
- We put the magnets on the LBB damper ring using the template.
- We locked various combinations of keystones and measured the vertical resonance frequencies of the unlocked filters.
- We spent time on getting the geophones working. The original descrambler adapters had gone missing, so Enzo created three new ones. We borrowed a cable to replace one that had broken. The geophone distributor (S1402167) failed (no power on the negative rail), and a replacement borrowed from SR3 (S1605513) kept switching off.
Plan for week of 9/13
Plan for week of 9/19
No work Mon 9/18 (敬老の日)
Mark, Fabian, Enzo, Ohishi-san, Hirata-san, Yoshioka-kun (Tue, Wed, Thu, Fri), Kozu-kun
- Install LBB damper magnet rings in tank.
- Remove tank lid.
- Install suspension.
Vacation Info
Mark: 10/16-24