Scraps of text for incorporation in the VIS Meeting Minutes

KAGRA/Subgroups/VIS/MeetingNAOJ

Notes for SRM Klog on 19-11-2020

F1 measurements

Conditions

Desription of measurements

  1. I left F1 keystone at -182 um (10,000 counts of actuation) free swinging last night and, despite the time elapsed, the oscillation at 312.5 mHz has not damped (picture 1p1 and 1p2). It has an amplitude of 30 um-pp. I assume it continues because the excitation hasn't ceased. The transfer function looks very good (1p3) but the resonant frequency is at 273 mHz not at 312.5 mHz.
  2. I removed the actuation and the keystone goes down to -572 um. The large oscillation at 312.5 mHz is gone; we see the highest peak at the resonant frequency of 281 mHz (pictures 2p1, 2p2 and 1p3).The transfer function looks also very good. The peak shows up at 273 mHz not at 281 mHz (picture 2p4).
  3. I turned the actuation on again (10,000 counts). The large oscillation is back, this time at 304 mHz, together with other oscillations in that frequency neighborhood (pictures 3p1 and 3p2). Washimi-san and Hirata-san are working around SRM now. Then I turned the control system on, damping only, but it didn't damp it. I increased the gain but it became unstable. I don't have the TF in Foton to check the UGF and gain, so I gave up damping it.
  4. I increased the actuation to 14,400 counts to bring the keystone around zero. The oscillation is still there (pictures 4p1, 4p2) and it appears in a slightly higher frequency, at 328 mHz. The transfer function shows an unhealthy system: the peak around 280 mHz is gone and a shorter peak appears at 304 mHz instead (picture 4p3). The coherence at that frequency is also high for a resonance (0.91).

Klog for 16-11-2020

With Hiarata-san and Washimi-san.

Preparation from the control room

In situ preparation

Work inside the chamber

Type-B

With Washimi-san.

Type-Bp

With Washimi-san

General

About LVDT cards

[Fabian and Washim-san]

With the new information that Alessadro (Nikhef) provided a few weeks ago, we began measuring the settings in PR suspensions.

Type-B

[Fabian and Washimi-san]

Type-Bp

[Fabian and Washimi-san]

Type-B

[Fabian]

Possible activities for the next weeks (subject to Takahashi-san's approval):

Type B

Report for the week of the 19th of October 2020.

[Fabian]

General

Type B

Report of the week of the 12th of October

Type B

Report of the week of the 28th of Septermber

Type B

Report for the week of the 7th of September 2020.

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:

In the context of the writing

Type B

Report

Report

Report for the week 16-12-2019

Plan for next week

Report for the week 09-12-2019

Plan for next week

Vacation/Travel Info

Type B

Report for the week 23-09-2019

Plan for next week

Vacation/Travel Info

Report for the week 23-09-2019

Plan for next week

Vacation/Travel Info

Type B

Report for the week 13-09-2019

Type B

Report for the week 02-09-2019

Plan for next week

Report for the week 26-08-2019 (Written by Fabian)

Plan for the week 02-09-2019

Type B

Report for the week 15-08-2019 (Written by Fabian)

Plan for the week 19-08-2019

Type B

Report for the week 05-08-2019 (Written by Fabian)

Plan for the week 15-08-2019

Report for the week 7/29 (Written by Fabian)

Plan for the week 8/5

Type B

Report for the week 7/22 (Written by Fabian)

Plan for the week 7/29

Vacation/Travel Info

Type B (Mark)

Report for the week 7/15 (Written by Fabian)

Plan for the week 7/22

Vacation/Travel Info

Type B (Mark)

Report for the week 7/8 (Written by Fabian)

Plan for the week 15/8

Vacation/Travel Info

Type B (Mark)

Report for the week 7/1 (Written by Fabian)

Plan for the week 7/8

Type B (Mark)

Report for the week 6/24 (Written by Terrence and Fabian)

Plan for the week 7/1

Vacation/Travel Info

Type B (Mark)

Report for the week 6/17

Plan for the week 6/24

Vacation/Travel Info

Type B (Mark)

Report for the week 6/10

BS

Type B (Mark)

Report for the week 6/3

SRM Inertial Damping and Residual Motion Stuff

RMS Displacement:

Requirement

Result

L

0.4 µm

0.1076 µm

P

1 µrad

0.0569 µrad

Y

1 µrad

0.0598 µrad

RMS Velocity:

Requirement

Result

L

0.5 µm

0.1014 µm/s

P

/

0.2165 µrad/s

Y

/

0.1776 µrad/s

SR3 Inertial Damping

Type B (Mark)

Report for the week 5/27 (written by Fabian)

Type B (Mark)

Report for the week 5/20 (written by Fabian)

Plan for the week 5/25

Report for Golden Week

Report for the week of 5/6

Report for week of 5/13

Plan for week of 5/20

Vacation/Travel Info