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==== 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.		 ==== Report for week of 1/15 ====
 * We swapped in the other available BF, and it was rather better: only 0.3 mm of keystone tilt rather than 1.3 mm. We will use it for the SR2 and then think about whether we want to use or rebuild the original one.
 * We finished the preparation of the second BF, setting the yoke, adding the new-style cable clamps etc.
 * We changed the 1.6 mm sockets on the BF LVDT cable to 1.0 mm ones to match the pins on the LVDT wires. The specification of the cable in D1503901 was apparently wrong. We will update it (today) before doing the cable order for the SR3 and SRM.
 * We updated the BS real-time model and screens, adding support for a damping filter common to both the OL-TM and OL-IM paths, per Izumi-san's suggestion in G1807653.
 * We set up the router for the SR2 rack and got the SR2_IM pico driver and both stepper motors on the network (the SR2_BF pico is still on order).
 * We did prep for the top filter test:
  * We received, unpacked and temporarily stored a shipment of weights and other parts.
  * We removed the top crossbars from the SR3 assembly frame.
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==== Plan for week of 1/29 ====
 * Enzo at Mitaka 1/29 and most of 1/30, then vacation.
 * Kozu-kun away.
 * All others at Kamioka.
 * Make in-air pico adapter cables.
 * Test IM picos and BF yaw pico.
 * Test FR.
 * Calibrate LVDT.
 * Get screws for ballast mass from Takahashi-san.
 * Install ballast mass in BF.
 * Set up for F0 test.
  * Lower IM crossbars in SR3 assembly frame.
  * Open curtain on SR3 crane slot.
  * Set up dummy load (weight carrier, rods etc).

==== Plan for week of 2/5 ====
 * Enzo on vacation; all others at Kamioka.
 * Build IRM around IM.
 * Cable/test/adjust IM OSEMs.
 * Time permitting, do TFs from IM OSEMs to themselves and to optical sensor.

==== Plan for week of 2/12 ====
 * Enzo on vacation; all others at Kamioka.

==== Vacation Info ====
 * Enzo 1/30-2/19 (at Mitaka 1/29, part of 1/30)
 * Kozu-kun 1/29-2/2

Scraps of text for incorporation in the VIS Meeting Minutes

KAGRA/Subgroups/VIS/MeetingNAOJ

Type B (Mark)

Report for week of 1/15

  • We swapped in the other available BF, and it was rather better: only 0.3 mm of keystone tilt rather than 1.3 mm. We will use it for the SR2 and then think about whether we want to use or rebuild the original one.
  • We finished the preparation of the second BF, setting the yoke, adding the new-style cable clamps etc.
  • We changed the 1.6 mm sockets on the BF LVDT cable to 1.0 mm ones to match the pins on the LVDT wires. The specification of the cable in D1503901 was apparently wrong. We will update it (today) before doing the cable order for the SR3 and SRM.
  • We updated the BS real-time model and screens, adding support for a damping filter common to both the OL-TM and OL-IM paths, per Izumi-san's suggestion in G1807653.
  • We set up the router for the SR2 rack and got the SR2_IM pico driver and both stepper motors on the network (the SR2_BF pico is still on order).
  • We did prep for the top filter test:
    • We received, unpacked and temporarily stored a shipment of weights and other parts.
    • We removed the top crossbars from the SR3 assembly frame.

Plan for week of 1/29

  • Enzo at Mitaka 1/29 and most of 1/30, then vacation.
  • Kozu-kun away.
  • All others at Kamioka.
  • Make in-air pico adapter cables.
  • Test IM picos and BF yaw pico.
  • Test FR.
  • Calibrate LVDT.
  • Get screws for ballast mass from Takahashi-san.
  • Install ballast mass in BF.
  • Set up for F0 test.
    • Lower IM crossbars in SR3 assembly frame.
    • Open curtain on SR3 crane slot.
    • Set up dummy load (weight carrier, rods etc).

Plan for week of 2/5

  • Enzo on vacation; all others at Kamioka.
  • Build IRM around IM.
  • Cable/test/adjust IM OSEMs.
  • Time permitting, do TFs from IM OSEMs to themselves and to optical sensor.

Plan for week of 2/12

  • Enzo on vacation; all others at Kamioka.

Vacation Info

  • Enzo 1/30-2/19 (at Mitaka 1/29, part of 1/30)
  • Kozu-kun 1/29-2/2

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