Scraps of text for incorporation in the VIS Meeting Minutes
Type B (Mark)
Report for week of 7/2
We double-checked the bounce frequency and it was indeed around 0.5 Hz with the CuBe auxiliary spring installed.
- We prepared (but did not yet install) 6 arc weights for tuning the IP.
- We unlocked the security structure from the assembly frame, and raised the whole system on the top jacks. We then unlocked the IP and adjusted the leveling so the IP was centered. We then had to loosen two of the poles at the top level of the security structure to make it vertical again, because it turns out that the jack receptacles (which also serve as the IP leg bases) are welded at very uneven depths in the bottom surface of the PI, so the IP and the bottom surface can't be level at once.
- We debugged an issue with the height of the payload. It turns out that due to a buildup of errors (especially an extra 3 mm between the SF and BF), the payload is some 5-6 mm low with the F0 keystone at CAD height. Since the frequency is roughly independent of height around 0.5 Hz, we decided to go with a higher F0 keystone.
- Enzo and Eleonora routed all the SF/... cables up to the PI.
- We found we needed 4.7 kg of extra mass to get the desired keystone height, so we decided to put the third Cu segment (3.3 kg) back on, purely as ballast.
- We put some extra small masses on the SF cap to level it. The suspension is now fully ballasted and trimmed except for 1 Promec mass (455 g) standing in for the new PI yaw stepper motor assembly (estimated 330 g) which is yet to arrive.
- We took all the SR sat amps back to Mozumi to get new capacitors installed, and grabbed three spares for use while that is being done.
- We investigated and documented Tanaka-san's watchdog for the BS, to see if the BIO Converter chassis that it uses could also drive reset lines for stepper motor driver boxes.
- Hirata-san and Terrence characterized the last 4 F0 blades.
Hirata-san and Terrence installed blades in the top filter for SR2 and tuned it to 0.5 Hz (with the CuBe auxiliary spring) over three rounds of compression.
Plan for week of 7/9
- Mark, Enzo, Hirata-san, Kozu-kun, Terrence at Kamioka Mon-Fri.
- Check/restore alignment of payload, especially optic pitch.
- Install and cable geophones.
- Install arc weights.
- Tune IP.
- Install, cable PI yaw stepper.
- Make three in-air stepper splitter cables for SR2, SR3 and SRM.
- Calibrate PI LVDTs and FRs.
- Cabling, testing, TFs.
===== F0/LBB Stuff ====
- Finalize PI #1 for SR2; crane into SR2 cleanbooth.
- Remove SR3 tank lid, crane LBB rings to top of lower half of the tank, clamp in position.
- Set tank jacks to nominal height.
- Clear space for PI #2 (SRM) work.
Plan for week of 7/16
- Lock suspension.
- Crane into tank.
- Unlock suspension.
- Rearrange cables.
- Install correct IP in PI #2.
- Crane PI #2 to second floor.
- Rebuild top filter of PI #2.
To-Do Lists, Schedule
- Terrence: 8/24-26 f2f, then returns to Hong Kong.
- Enzo: 9/14 JPS, 9/15 through 10/8 vacation in Chile.