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 * Showed the calculation result of one candidate design. It show reduction more than 100dB at 100Hz.
 * Continue the calculation, then will go to the breadboard test,
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 * Though the safe mode with DC controls were employed for the shutdown phase in the previous meeting, the chief meeting set the ALINGNED mode for the suspended phase. Even if KAGRA went to the shutdown phase, the ALIGNED mode will be kept.  * Though the safe mode with DC controls were employed for the shutdown phase in the previous meeting, the chief meeting set the ALIGNED mode for the suspended phase. Even if KAGRA went to the shutdown phase, the ALIGNED mode will be kept.

Agenda/Minutes of the VIS Meeting on 2020/5/1

2020/5/1 14:00 - 14:40

Zoom Meeting

Participants: Takahashi, Hirata, Sato, Shoda, Tanaka, Aso, Fabian, Lucia, Miyo

Task list towards O4

Schedule afetr O3

Progress report

General

  • Making the gurdians for the suspended mode.

Type-A

  • Measured the noise budgets.
  • Checked the health of suspensions.

Type-B

Report for the week of the 27th of April 2020.

In the context of the Type-B paper I checked the noise level of the gephones: I did a calculation of the expected sensitivity and campared with Fujii-kun's measurements:

  • The calculation is based on Mathieu Blom's, reported in his PhD thesis (Nikhef). In case you check it please be aware there are two typos in Eq. 5.10.

  • It includes the thermal noise of the pick-coil resistance, geophone suspension thermal noise and pre-amplifier noise, which is dominant. See this plot: SR2_geo_sensitivity_budget.png.

  • The calculation of the pre-amplifier noise is consistent with Tananori's calculation and measurement from the prototype times. See this plot: SR2_geo_preamp_noise.png.

  • In the case of geophone No. 5 from SR2 the measured noise at 200 mHz is 3.6 times larger than the calculation. I don't know where the discrepancy may come from. See this plot: SR2_geo_sensitivity.png.

About the paper:

  • Fabian is revisiting the Matlab control model, with a particular emphasis on inertial damping.
  • There was more writing done.
  • Mark is checking and beautifying the already written text.

Type-Bp

Type-C

  • Modification of the IMMT2 suspension.
    • The ghost beams are interfering with the pillar of suspension. The footprint should be changed.

Controls

Electronics

  • Showed the calculation result of one candidate design. It show reduction more than 100dB at 100Hz.
  • Continue the calculation, then will go to the breadboard test,

Post O3

  • KAGRA went to the suspended phase from 28th April.
  • Though the safe mode with DC controls were employed for the shutdown phase in the previous meeting, the chief meeting set the ALIGNED mode for the suspended phase. Even if KAGRA went to the shutdown phase, the ALIGNED mode will be kept.
  • The declaration of emergency state due to COVID-19 will be extended more one month.

  • Tasks for the papers will be available after 11th May at earliest (Request).

  • Papers
    • Type-A: Lucia(Performance), Fujii(Sensor collection).
    • Type-B: Fabian
  • Towards O3c

Safety

Discussion

Travel Plans

Next meeting

On 2020/5/15(Fri)

KAGRA/Subgroups/VIS/VISMinutes20200501 (last edited 2020-05-01 15:01:09 by RyutaroTakahashi)