Agenda/Minutes of the VIS Meeting on 2020/7/31

2020/7/31 14:00 - 15:30

Participants: Takahashi, Hirata, Miyo, Fabian, Aso, Sato, Washimi, Tanaka, Shoda, Terrence

Progress report

The accelerometer with LVDT was tested at the site (klog).
- The ACC was set on the floor of IYV area. The folded pendulum was tuned to 0.24Hz. The servo loop was configured by Miyo-san using KAGRA digital system.
- When we finished the final setting on Wednesday afternoon, the large earthquake (M7.8) was happened at Aleutian islands. So Miyo-san measured and evaluated the spectrum later.
[Miyo] Offload the ITMX_GAS_F1,2 klog#14820

In last week, we have implement inertial damping for all type-B suspensions. In the process of geophone diagonalization, we discovered that the LVDTs were actually poorly diagonalized so we attempted our best to diagonalize it. Afted that, we rediagonalize the actuation and geophones. In the input filter of the geophones, there are redundant 4-th order high-pass filters at 0.01 called DCcut. These completely ruined the phase performance of the geophones at 0.1 Hz. We disabled those filters and moved the cutoff of the original high-pass to 0.003 Hz. After that, we did noise budget and fitting. At last we optimized filters for according to those fit. Klogs are 14800, 14801, 14802, 14803.
A mysterious coupling was found from MICH to BS pitch and yaw. Yesterday, we discovered that analog dewhittening filter for one of the coils were enabled and cannot be turned off. Yamamoto-san found that the coil-driver was faulty.
Paper: I finished writing. I'm waiting for Enzo's comments to submit to CPC and share it with the rest of VIS people.

Modified the LVDT board. DC power supply is necessary for the test which is planed in the next week.
#6 pin in the SG board is available for the internal connection to the LVDT board. Jumper pin is necessary.

KAGRA is in "Upgrade phase for O4". Upgrade of SR controls were performed. The accelerometer with LVDT was tested at the site.
Plan for cleaning the clean booth (EN, JP) will be submitted by 3rd. Aug. It is necessary to make the inventory with location (example for Type-A).
- [Washimi] PEM team introduce the Holobuilder (Google street view like tool). Let's discuss about cleanup plan with this tool.
Preparation work (pre-cleaning) will be started from 17th Sep. Cleaning schedule.png.

cf. Post Obs. task (Request), Task for O3c (Plan, Sheet), Task towards O4 (List), Schedule towards O4 (Chart).

[Washimi] Room temperature and GAS status https://www.icrr.u-tokyo.ac.jp/~washimi/KAGRA/SEM/fig_GAS/
- The temperature in mine dropped during July 9th - July 19th (-0.8degC). We couldn't find this until July 22th due to the trouble and maintenance of the network.
- We added 2 heaters on July 28th.

KAGRA/Subgroups/VIS/VISMinutes20200731 (last edited 2020-07-31 15:40:25 by RyutaroTakahashi)