KAGRA Logbook

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PEM (Center)

tatsuki.washimi - 11:36 Wednesday 26 February 2020 (13181)

BNS range vs OMC chamber vibration

I checked the relationship between BNS range and OMC chamber vibration.
The channels are

K1:DAS-RANGE_BNS
K1:PEM-SENSOR_RACK_OMC1_DSUB2_OUT_DQ : an acceleormeter putted on the foot of OMC chamber ("DSUB2" in klog13136)

In the trend plot for this 12hours, we can see the periodical (~140min) pulses in ACC.
At these time (with ~3min deray), the BNS range becames worse about 50kpc (e.g., 300kpc -> 250kpc).
I guess it is comming form the air complessor for a OMC gate valve.

I can analysI it as a PEM injection

start & end GPS time are:

2020-02-25 14:34:05 (1266676296, 1266676344)
2020-02-25 16:56:38 (1266684921, 1266684969)
2020-02-25 19:19:55 (1266693550, 1266963597)
2020-02-25 21:43:55 (1266702185, 1266702232)
2020-02-26 00:07:55 (1266710810, 1266710858)

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Comments to this report:

tatsuki.washimi - 12:48 Wednesday 26 February 2020 (13182)

DARM Spectrum for loud (red) vs. quiet (blue)

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tatsuki.washimi - 13:13 Wednesday 26 February 2020 (13183)

I analyzed the 2020-02-25 14:34:05 UTC pulse as a PEM injection.

(1) PSDs of DARM and ACC for "injected" (GPS 1266676296, +48) and "background" (GPS 1266676176, +64)

(2) Statistical significance of excess (threshold = 3 sigma)

(3) Results of noise projection for the background data

Roughly speaking, the OMC ground noise budget is not dominant for the quiet term.

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tatsuki.washimi - 13:18 Wednesday 11 March 2020 (13473)

I reproduced the analysis for OMC complessor injecion on 2020-02-25, with ACC and MIC

injection : from 1266676297, 45 sec
background : from1266676248, 45 sec

left : ACC, right : MIC

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