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| * SR2 LVDT sensitivity measured when the keystones were locked. | * [[http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/Subgroups/VIS/TypeB/SR2detail|SR2 LVDT sensitivity]] measured when the keystones were locked. |
Agenda/Minutes of the VIS Meeting on 2020/3/27
2020/3/27 14:00 -
Participants:
Progress report
Type-A
Past week report
Evaluated the LVDT sensor on the NIKHEF ACC. It was better than the fiber sensor and the WLI. (Plot and data)
Plan for coming weeks
Type B
Past week report
The hammering test made by Yokozawa-san revealed that the BS large external frame is very sensitive to disturbances ("Very very very" funny klog 13603). "Very very very" gentle touching produces saturation of the IP actuators (klog 13661). I don't remember the other frames and suspensions being as delicate. After O3 I aim to reproduce the effect in the BS suspension and check the SR ones. We should notify Mirapro in case the situation is particularly bad in case they believe adjustment to the frame screws and bolts is required.
Temperature change in BS clean both: it has drifted from 23.7 °C to 22.9 °C in 60 days (klog 13663). Such a large change has produced an increase in the feedback signals of the IP coils. Particularly uncomfortable is H2 actuation which reaches -18,500 counts. For H2 I changed the limit from 20,000 to 25,000 counts. I asked Miyoki-san about what was the plan for O4 and he suggested VIS should take care. Using heating jackets was suggested.
During the long weekend Michimura-kun checked oplev diagonalization in SRM and balanced the TM coils in all SR suspensions (klog 13764).
- Initially there was a confusion with some signs because he was using the oplev far out of range and because the coil-magnet actutors in the BS are at the front and not at the back of the optic as in the SRs. Nevertheless, the situation was clarified.
- His diagonalization procedure yielded similar results to Terrence's, so he trusted the work previously done and left the other Type-B oplevs as they are. We still should check just to make sure the earthquake didn't change anything significantly, but it doesn't seem to be an urgent task for now.
On Monday he centered the SR2 and SRM QPDs (along with all PR ones). (klog 13764.)
He wrote a Python script to balance the TM coils (klog 13739) based on the method used by Ushiba-san on PR3 (klog 13614). It actuates each TM coil separately at a particularly frequency and uses the transfer functions to yaw in order to quantify the difference among actuators. It then uses the value in H2 to normalize the the other three values.
On the 17th of March they compiled the BS payload real-time mode but failed (klog 13818) due to the absence of Dolphin network ports in other real-time models. Apparently, later they accidentally tried to install whatever executable was there. That created a problem with burt files, which were not created for a whole week. Later they corrected the real-time model and installed it (klog 13825).
- I worked in the Type-B paper and added some of the data to the wiki.
SRM OSEM sensitivity measured when flag was rigidly locked.
SR2 LVDT sensitivity measured when the keystones were locked.
- Mark says hello to all. He's in lockdown at home.
Yamamoto-kun modified some C code in order to add more configuration states to the coil drivers whitening configurations using the BIO (klog 13844). The new states are already enabled in Type-A models but not in Type-Bp and Type-B. We just need to compile the models again if we want to enable the new states.
Shoda checked the geophone response using SRM to investigate from where the phase delay comes from: jupyternotebook
Plan for coming weeks
- On Sunday we will do hammering test in SR area.
- Disable Guardian check of coil drivers hardware whatchdog.
- Post information about oplevs.
Type-Bp
Past week report
- In the discussion with Michimura-kun, we found that the sign on the length oplev signal is wrong in PRM. It was fixed.
- Also, the magnet polarization of PR3 seems to be all opposite.
Plan for coming weeks
Type-C
Past week report
Plan for coming weeks
VIS electronics
Past week report
Plan for coming weeks
Safety
Discussion
Temperature control around the chambers. (Requested temperature for Type-B suspensions: 7420.)
Travel Plans
- Travel (Week of 3/30):
- Takahashi:
- Sato:
- Hirata:
- Shoda:
- Fujii:
- Tanaka:
- Travel (Week of 4/6):
- Takahashi:
- Sato:
- Hirata:
- Shoda:
- Fujii:
- Tanaka:
Next meeting
On 2020/4/3(Fri)