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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 put lock nuts on the F0 FR and calibrated the F0 LVDT against FR position and keystone height.
 * Enzo traced the issue with the geophones to a specific cable.
 * We measured the BF and F0 GAS resonant frequencies.
 * We adjusted the spacing of the SR damper.
 * We double-checked the BS pitch with the OL.
 * We debugged the PI yaw mechanism. We managed to get the return spring properly adjusted, but the stepper motor tends to jam because of the strange design.
 * '''We prepared the suspension for lifting and craned it into the tank.'''
 * Hirata-san fixed an issue with one of the nailheads on the LBB intermediate ring support rods not properly seating, by removing the rod and reinstalling it upside down (with the problem nailhead in a less critical position).
 * Enzo and team moved all the in-air cables from the assembly frame to the tank.
 * Fabian and Ohishi-san unlocked the bottom section of the suspension and got it hanging freely.
 
==== Plan for week of 9/25 ====
Mark, Fabian, Enzo (Mon, Tue), Ohishi-san (Tue, Fri), Hirata-san, Yoshioka-kun (Tue, Wed, Fri), Kozu-kun
 * Finish moving in-air cabling and feedthroughs and reconnect in-vacuum cables (through Cu O-rings).
 * Unlock rest of suspension and readjust.
 * Debug electronics.
 * Unclamp LBB ring "sandwich" so LBB Cu ring is suspended on upper rods.
 * Install LBB lower rods and hook LBB.
 * Adjust LBB damper Cu-magnet gap.
 * Measure required ballast for LBB.
 * Remove First Contact, try OL.
 * Prepare for SR2 work.
Line 9: Line 31:
 * 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 10/2 ====
Kamioka: Mark, Enzo, Fabian, Ohishi-san.
 * TFs etc.
Mitaka: Hirata-san?
 * SF design/purchasing.
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==== Plan for coming weeks ====
For more detail, see [[KAGRA/Subgroups/VIS/TypeB/ToDo]].

Week of 5/29, 6/6:
 * Cabling:
  * Route BF/... cabling up past SF to PI.
  * Route SF cabling up to PI.
  * Add Type 3 extensions to SF/... cables.
  * Move vacuum flanges to positions on assembly frame more convenient for next stage (accessible from second floor, one on each corner of frame).
  * Move in-air cabling to match flange positions.
  * Cable and test PI vertical LVDT.
  * Calibrate PI vertical LVDT.
  * Set yoke on PI vertical LVDT (if necessary).
  * Cable and test PI yaw stepper.
  * Cable and test PI vertical stepper.
  * Cable and test PI horizontal steppers.
  * Cable and test PI horizontal LVDTs.
  * Calibrate PI horizontal LVDTs.
 * Crane into tank.		 ==== Vacation Info ====
Mark: 10/16-24
Enzo: 9/27-29

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 put lock nuts on the F0 FR and calibrated the F0 LVDT against FR position and keystone height.
  • Enzo traced the issue with the geophones to a specific cable.
  • We measured the BF and F0 GAS resonant frequencies.
  • We adjusted the spacing of the SR damper.
  • We double-checked the BS pitch with the OL.
  • We debugged the PI yaw mechanism. We managed to get the return spring properly adjusted, but the stepper motor tends to jam because of the strange design.

  • We prepared the suspension for lifting and craned it into the tank.

  • Hirata-san fixed an issue with one of the nailheads on the LBB intermediate ring support rods not properly seating, by removing the rod and reinstalling it upside down (with the problem nailhead in a less critical position).
  • Enzo and team moved all the in-air cables from the assembly frame to the tank.
  • Fabian and Ohishi-san unlocked the bottom section of the suspension and got it hanging freely.

Plan for week of 9/25

Mark, Fabian, Enzo (Mon, Tue), Ohishi-san (Tue, Fri), Hirata-san, Yoshioka-kun (Tue, Wed, Fri), Kozu-kun

  • Finish moving in-air cabling and feedthroughs and reconnect in-vacuum cables (through Cu O-rings).
  • Unlock rest of suspension and readjust.
  • Debug electronics.
  • Unclamp LBB ring "sandwich" so LBB Cu ring is suspended on upper rods.
  • Install LBB lower rods and hook LBB.
  • Adjust LBB damper Cu-magnet gap.
  • Measure required ballast for LBB.
  • Remove First Contact, try OL.
  • Prepare for SR2 work.

Plan for week of 10/2

Kamioka: Mark, Enzo, Fabian, Ohishi-san.

  • TFs etc.

Mitaka: Hirata-san?

  • SF design/purchasing.

Vacation Info

Mark: 10/16-24 Enzo: 9/27-29

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