Scraps of text for incorporation in the VIS Meeting Minutes
Type B (Mark)
Report for week of 11/12
- Kozu-kun noticed the BS OL was out of range, and Fabian and Fujii-kun investigated. It turns out that the temperature has risen by over 2°C, so all the GAS filters have sagged and several stages are touching. Miyoki-san and Furuta-san are looking at what can be done.
- We ordered three more geophone cables in the standard (non-flipped pinout) to save time during the December vent, where we will replace at least two of the preamps to fix issues and take the opportunity to put in non-flipped ones.
- We cabled all the SF/... through to the rack and checked that all items worked.
- We did the vertical height survey and found that as with SR2 and SR3, the chain is longer than the CAD, this time by ≈7 mm, and again mostly between the SF and BF. We decided on a keystone height of 11.5 mm (5 mm higher than CAD), which can be achieved with 1 kg more on the SF and 1 kg in reserve for a yaw stepper mechanism. We reset the height of the yoke to give near-zero LVDT output for the new nominal height, and corrected the sensing and actuation signs, but still need to do the calibration.
- The final SRM small glass mirror became available, so we had Hirose-san ship it to us so we can install it while the suspension is still on the assembly frame. Hirata-san ordered shims to make up the new recommended thickness of 1.4 mm and a micrometer to check the combination, which should arrive on Monday 11/26.
- Enzo took calibration data for the last batch of geophones, for SRM. We had to borrow cables from SR2 because one cable was missing and another was miswired. And it turned out that one of the SR2 cables was defective as well. But if we can find two possibly borrowed by Okutomi-san and rewire one, we should have enough for SR2 and SRM. The geophones appear to be healthy and we will seal them next week.
- We raised the PI clear of the assembly frame and unlocked and centered the IP. We calibrated the IP LVDTs, and reversed connections to get positive LVDT output for positive yaw. We borrowed a HPCD from SR3-IM-V for the SRM IP but haven't checked the actuation yet.
- While we were grabbing geophone cables from SR2, we added extra arc weights to get the IP frequency below 0.1 Hz.
- Akutsu-san showed us how to install the OL transmitter support pillar, receiver shelf and viewports. We believe we have the parts to finish setting up the SR2 OL.
To-Do Lists, Schedule
Plan for week of 11/26
- Clean tools and metal parts for final SRM glass mass.
- Swap in final glass mass.
- Adjust SF trim mass.
- Check/adjust alignment of SS.
- Calibrate IP LVDTs.
- Add arc weights and geophones.
- Improve centering/tuning of IP and SS alignment.
- Disconnect cables at feedthroughs, lock suspension.
- Crane into tank.
- Finish OL setup
- Control loops.
Plan for week of 12/3
- f2f Meeting at NAOJ - no Kamioka work.
Plan for week of 12/10
- Prepare for vent of BS.
BS work - see KAGRA/Subgroups/VIS/TypeB/ToDoBS.
- Hirata-san at Mitaka, Fri 11/30 (medical check for solvent use).
- Enzo at Mitaka, Fri 11/30 (Mitaka day).