KAGRA Logbook

DetChar (General)

kaori.obayashi - 22:08 Tuesday 27 September 2022 (22222)

Investigation of stationarity of accelerometers

[Yokozawa, Yuzu, Yamazaki, Murakoshi, Obayashi]

The motivation for this study is to evaluate the stationarity of environmental monitors.
When the candidate of GW signal is detected, the GW signal can be validated by using the well-characterized environmental monitors.
As a first step, we analyzed the data of the accelerometers (K1:PEM-ACC_EXA_TABLE_TX_Z_OUT_DQ, K1:PEM-ACC_EXA_TABLE_RX_Z_OUT_DQ).
We plotted an averaged ASD with percentiles for each 10-minute interval for one day of these data on 2022/4/7 17:00 - 2022/4/8 17:00 (during O3GK). See the attached images.
We found that a line-like feature around 40 Hz may be non-stationary.

Future work

By using one week data, check behavior and trends.
Same work at the other sensors.
Develop the algorithm to evaluate stationarity.

Comments to this report:

hirotaka.yuzurihara - 9:41 Wednesday 28 September 2022 (22227)

I post the screenshots instead of Obayashi-san.

Images attached to this comment

kaori.obayashi - 7:59 Friday 30 September 2022 (22257)

[Yokozawa, Yuzu, Yamazaki, Murakoshi, Obayashi]
We analyzed the data of following 6 environmental monitors during O3GK run and those of the same channels on this August and September.
・K1:PEM-ACC_EXA_TABLE_TX_Z_OUT_DQ
・K1:PEM-ACC_EXA_TABLE_RX_Z_OUT_DQ
・K1:PEM-ACC_EYA_TABLE_TX_Z_OUT_DQ
・K1:PEM-ACC_EYA_TABLE_RX_Z_OUT_DQ
・K1:PEM-MIC_EXA_BOOTH_EXA_Z_OUT_DQ
・K1:PEM-MIC_EYA_BOOTH_EYA_Z_OUT_DQ
Positions of these monitors have been unchanged since O3GK.
We made ASDs for 8 hours with 10, 50 and 90% percentile for several epochs.
Figures are uploaded on JGW doc.
We found that the ASD of the channel, K1:PEM-ACC_EYA_TABLE_TX_Z_OUT_DQ is changing gradually from late August this year.
We also found the simultaneous, similar behavior between RX and TX accelerometers of EYA during O3GK.
ASDs of microphone look stable.We will continue this study.

Images attached to this comment

tatsuki.washimi - 9:32 Monday 03 October 2022 (22303)

There was a PCal work at EYA area on 2022-08-26.
https://klog.icrr.u-tokyo.ac.jp/osl/?r=21909

One possibility is the cable for this ACC might be disconnected during this work.

takaaki.yokozawa - 9:05 Thursday 06 October 2022 (22374)

I recovered it by changing the BNC-Dusb converter from Washimi-san made one to company one.

takaaki.yokozawa - 15:25 Thursday 13 October 2022 (22476)

Still there are some missing part (signal itself seems the accelerometer, but noise floor for low frequency is larger.)
Try to change the power supply itself?

Images attached to this comment