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Size: 3286
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Size: 1874
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| Deletions are marked like this. | Additions are marked like this. |
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| At Kamioka (Mark, Fabian, Enzo, Hirata-san): | At Kamioka (Mark, Ohishi-san, Enzo, Yoshioka-kun): * We installed the cut-down ballast mass under the IM and tweaked the IM height and balance. * We checked the range of the BF FR. * We adjusted the BF yoke by 2.5 mm to make it give ≈0 output for nominal height. * We found a good gain setting for the LVDT driver and calibrated the BF LVDT. * We set up the optical sensors facing the RM. * We assembled the IRM (with OSEMs) around the IM and got it mostly adjusted. * We changed the k1visbs model to restore the as-designed mapping of OSEMs to DAQ channels. * We confirmed that the BF LVDT actuation coil and the TM OSEM coils were working. * We connected up the IRM OSEMs (with the new Type 5-1.7 cables) but found there was an electrical issue: all the OSEMs are reading back the same constant value, around 1115. * We left the suspension in a state suitable for TFs from BF GAS actuation to sensing (in vertical) and from RM OSEM actuation to the optical sensors (in horizontal) over the weekend. At Mitaka (Hirata-san): * Hirata-san did 2D drawings of the SR LBB rods and sent off an RFQ. * Hirata-san did several cost-reduction negotiations with Mirapro. |
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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. |
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| ==== Plan for coming weeks ==== For more detail, see [[KAGRA/Subgroups/VIS/TypeB/ToDo]]. |
==== Plan for week of 8/28 ==== Kamioka: Mark (except Tue), Ohishi-san, Fabian (except Tue), Enzo (except Tue), Hirata-san, Yoshioka-kun (Fri), Kozu-kun (Thu, Fri). * Fix/adjust IRM OSEMs. * Add BF cap; cable and test BF-1 and BF-2 picos. * Lift and weigh BF/IRM/IM/RM/BS; adjust ballast mass. * Crane in SF. * Suspend BF/IRM/IM/RM/BS. |
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| 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. |
==== Plan for week of 9/4 ==== * Install SF cap; route cables. * Lift and weigh SF/BF/IRM/IM/RM/BS. * Adjust SF ballast. |
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| ==== Vacation Info ==== Mark: TBD Mid-Oct |
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, Enzo, Yoshioka-kun):
- We installed the cut-down ballast mass under the IM and tweaked the IM height and balance.
- We checked the range of the BF FR.
- We adjusted the BF yoke by 2.5 mm to make it give ≈0 output for nominal height.
- We found a good gain setting for the LVDT driver and calibrated the BF LVDT.
- We set up the optical sensors facing the RM.
- We assembled the IRM (with OSEMs) around the IM and got it mostly adjusted.
- We changed the k1visbs model to restore the as-designed mapping of OSEMs to DAQ channels.
- We confirmed that the BF LVDT actuation coil and the TM OSEM coils were working.
- We connected up the IRM OSEMs (with the new Type 5-1.7 cables) but found there was an electrical issue: all the OSEMs are reading back the same constant value, around 1115.
- We left the suspension in a state suitable for TFs from BF GAS actuation to sensing (in vertical) and from RM OSEM actuation to the optical sensors (in horizontal) over the weekend.
At Mitaka (Hirata-san):
- Hirata-san did 2D drawings of the SR LBB rods and sent off an RFQ.
- Hirata-san did several cost-reduction negotiations with Mirapro.
Plan for week of 8/28
Kamioka: Mark (except Tue), Ohishi-san, Fabian (except Tue), Enzo (except Tue), Hirata-san, Yoshioka-kun (Fri), Kozu-kun (Thu, Fri).
- Fix/adjust IRM OSEMs.
- Add BF cap; cable and test BF-1 and BF-2 picos.
- Lift and weigh BF/IRM/IM/RM/BS; adjust ballast mass.
- Crane in SF.
- Suspend BF/IRM/IM/RM/BS.
Plan for week of 9/4
- Install SF cap; route cables.
- Lift and weigh SF/BF/IRM/IM/RM/BS.
- Adjust SF ballast.
Vacation Info
Mark: TBD Mid-Oct