Differences between revisions 198 and 199
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At Kamioka (Mark, Ohishi-san, Enzo, Hirata-san, Yoshioka-kun):
 * We moved or covered stuff in the BS cleanbooth to prepare for the SR2 crane slot cutting and BS-> SR2 assembly frame move.
 * We put the service port covers back on at the BF level of the BS tank.
 * We used the PI jacks to center the bottom of the security structure around the RM.
 * We debugged a mechanical issue where the #2 IP LVDT had too narrow a gap between the moving and fixed parts, so that there was interference with only a very small clockwise yaw of the IP. We fixed it by moving the bottom baseplate (taking advantage of the fact that it was held by screws in oversize holes for this purpose).
 * We used the IP FRs to center the IP.
 * We set the gains on the IP LVDT driver.
 * We tested the picos and most of the steppers. The picos and IP steppers all work nicely. The PI FR and yaw steppers have jamming issues. We haven't tested the BF and SF FR steppers.
 * We debugged an issue with one of the geophones (#1) which has a DC offset. We did cable swaps and determined that the issue is internal to the geophone pod. A second geophone (#2) saturates at a suspiciously small voltage on the negative side. Again the issue is internal.
At Mitaka (Fabian, Hirata-san):
 * Fabian designed an improvement to the PI yaw stepper driver mount to stop the stepper jamming.
 * Fabian worked on a plan to measure the load capacity of the SR PIs.
 * Hirata-san did 2D drawings of the PI for the SR, and of SF2 and SRM in their vacuum chambers.
 * Hirata-san did drawings if the SR LBB damper rings and asked for quotes.
 * Hirata-san asked for quotes for SR secondary wire breakers and SR IM/IRM lock screws
 * Hirata-san ordered SR IM wire clamps.
 * Hirata-san worked on parts lists for SR cable clamps.		 At Kamioka (Mark, Ohishi-san, Fabian, Enzo, Hirata-san, Kozu-kun):
 * We couldn't count for a bubble level, so we removed a service port cover, searched again on top of the BF and found it.
 * We locked the LBB, put the table KOACH filters on the table. Ohishi-san removed the FC in two stages (AR side on Tue, HR side on Fri).
 * Ohishi-san measured the height of the SS and optic relative to the tank and found the optic was 3 mm low but the SS was 2 mm high. According to the GAS LVDTs, the suspension had not sagged but was 1.7 mm high.
 * Therefore we raised the suspension by 9 quarter-turns of the tank jacks (4.5 mm) to get the optic in the right position after (future) downward adjustment of the GAS filters.
 * We put the GAS LVDT calibration data as offsets and gains in the LVDTINF filters so the output would be height in µm relative to nominal.
 * We calibrated the IP LVDTs. We had worked around a mechanical interference due to the poor design of the old LVDTs by setting them to be 4 mm off-center with the IP locked centrally, but we discovered this was overkill and we have lost some linear range on the LVDT sensor in the opposite direction. If we have time we may move the LVDT bases 1-2 mm to a compromise position.
 * We worked with Simon to get the OL aligned and to learn the adjustment procedure.
 
At Mitaka (Hirata-san):
 * Hirata-san met with manufacturers and requested quotes.
 * Hirata-san made many assembly drawings for sections of the SR.
 * Hirata-san worked on compiling the SR inventory.

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, Kozu-kun):

  • We couldn't count for a bubble level, so we removed a service port cover, searched again on top of the BF and found it.
  • We locked the LBB, put the table KOACH filters on the table. Ohishi-san removed the FC in two stages (AR side on Tue, HR side on Fri).
  • Ohishi-san measured the height of the SS and optic relative to the tank and found the optic was 3 mm low but the SS was 2 mm high. According to the GAS LVDTs, the suspension had not sagged but was 1.7 mm high.
  • Therefore we raised the suspension by 9 quarter-turns of the tank jacks (4.5 mm) to get the optic in the right position after (future) downward adjustment of the GAS filters.
  • We put the GAS LVDT calibration data as offsets and gains in the LVDTINF filters so the output would be height in µm relative to nominal.
  • We calibrated the IP LVDTs. We had worked around a mechanical interference due to the poor design of the old LVDTs by setting them to be 4 mm off-center with the IP locked centrally, but we discovered this was overkill and we have lost some linear range on the LVDT sensor in the opposite direction. If we have time we may move the LVDT bases 1-2 mm to a compromise position.
  • We worked with Simon to get the OL aligned and to learn the adjustment procedure.

At Mitaka (Hirata-san):

  • Hirata-san met with manufacturers and requested quotes.
  • Hirata-san made many assembly drawings for sections of the SR.
  • Hirata-san worked on compiling the SR inventory.

Plan for week of 10/10

Kamioka: Mark, Fabian, Enzo, Ohishi-san, Kozu-kun. Mitaka: Hirata-san Holiday Mon 10/9, Open Day prep Fri 10/13.

  • Tune IP, do LVDT/stepper calibration.
  • Remove First Contact, try OL.
  • TFs, final preparation for alignment in week of 10/16.
  • SR procurement.
  • Design ballast for LBB.
  • Continue design of improved PI yaw adjustment, also improved F0 FR.

Plan for week of 10/16

Kamioka: all but Mark, Hirata-san Mitaka: Hirata-san

  • Work with alignment team.
  • SR procurement

Vacation Info

Mark: 10/16-24

KAGRA/Subgroups/VIS/TypeB/Minutes (last edited 2022-10-28 10:02:46 by fabian.arellano)