Scraps of text for incorporation in the VIS Meeting Minutes

KAGRA/Subgroups/VIS/MeetingNAOJ

Type B (Mark)

Report for week of 6/18

• Mark checked the health of the suspensions after an earthquake on Monday morning. The BS watchdog tripped and there was a few µrad change in the pointing, but otherwise it was fine. SR3 and SR2 were also fine.
• Mark, Enzo and Terrence finalized the trim mass on the BF to set the SF keystone height and BF pitch/roll.
• They weighed the SF/... section. With no internal trim mass in the SF but with the flying saucer and rod, but with 2 Promec masses for rough balance, it was 255.4 kg, so allowing 1 kg for cables and fine trim mass, we would like a PI load capacity of 256.4 kg.
• Enzo and Terrence cabled and tested the SF fishing rod, and reversed the connections on the SF LVDT actuation to bring it to standard polarity.
• Mark and Enzo made many improvements to the Type B MEDM screens.
• Enzo and Mark measured the BF and SF bounce frequencies (with the other keystone locked).
• Enzo replaced a HPCD that seemed to have failed during the bounce test (but had just had a watchdog trip), and then replaced the replacement, which really did fail. It turns out we need to avoid applying more than about 25000 counts of GAS actuation.
• Enzo offloaded the BF LVDT actuator with the BF FR to remove the need for a 10000 ct offset.
• Hirata-san and Kozu-kun struggled to tune the top filter for SR3 - see klogs 5310, 5324, 5337, xxxx. At first the results were somewhat unrepeatable, with high frequency and low load capacity. This was improved by using a torque wrench (set to 50 N.m) to tighten the blade base clamp screws, retightening the blade tip screws (which had worked loose) and tightening the collar on the end of the shaft of the magic wand. Eventually we decided on a compression of 30 mm, which should give a frequency of around 0.5 Hz if we remove one Cu damper segment from the SF. Hirata-san applied the 30 mm compression but we skipped another round of testing with the dummy load and will go straight to hanging the SF/... section on the assembly frame.
• We wrapped PI #1 (for SR2) and craned it from behind SR3 to behind SRM. We can now wrap PI #3 (for SR3) and crane it straight to the assembly frame.

Plan for week of 6/25

• Mark, Enzo, Hirata-san, Terrence at Kamioka Mon-Fri.
• Kozu-kun at Kamioka except Thu.
• --
• Shutdown Type B controls (as far as possible) in preparation for risk of accidental power outage during electrical work on 6/26.
• Prepare SF damper magnet ring and rods.
• Install PI #3 in SR3 AF.
• Suspend SF/... section.
• Lots of cable routing and testing.
• Move PI #1 (for SR2) over SRM tank to work area, install blades and tune.

Plan for week of 7/2

• Mark, Hirata-san, Terrence at Kamioka Mon-Fri.
• Enzo at Kamioka Mon-Wed.
• Kozu-kun at Kamioka except Wed.
• --
• Lock suspension.
• Remove tank lid and raise LBB damper rings.
• Crane suspension into tank.

To-Do Lists, Schedule

• KAGRA/Subgroups/VIS/TypeB/ToDoBS

• KAGRA/Subgroups/VIS/TypeB/ToDoSR

• JGW-L1807779 Type B Schedule (SR)

Vacation Info

• Kozu-kun: 7/4 Tokyo.
• Enzo: 7/5-6 NAOJ Party, Mitaka.
• Terrence: 8/24-26 f2f, then returns to Hong Kong.
• Enzo: 9/14 JPS, 9/15 through 10/18 vacation in Chile.