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DetChar (General)
koji.nagano - 20:03 Wednesday 02 May 2018 (4933) Print this report
Brief report of PEM injection in center area

[Nagano, Shimoda, Takano, Miyazaki, Kita, Tanaka, Kozu, Hasegawa, Miyo, Tanioka, Mori, Kaihotsu, Kuromiya, Itoh, Yamamoto (Univ. of Toyama), Hayakawa (with a lot of Yamamoto-san's (ICRR) help from remote)]

This is a brief report of PEM injection in center area.
Later, we will report the detail, for example noise projection to the sensitivity and so on.

We injected three types of signals to BS, magnetic field, sound, and impulse hummering.

Magnetic field
We injected magnetic field with a coil whose diameter is 1 m.
Comb wave at 9.2 Hz and filtered white noise (DC - 30 Hz and 30 - 300 Hz) were injected.
In all cases, we could not see any excess in Michelson sensitivity although the magnetic field was excessed from background by three order of magnitude.
This is good.
The spectrum in comb wave at 9.2 Hz are shown.
(K1:PEM-IY0_SENSOR5_OUT_DQ is magnetometer sensor signal in "Tesla" unit and K1:CAL-CS_PROC_C00_DISPLACEMENT_DQ is Michelson signal in "nm" unit.)
REF13 and REF5 are spectra without injection and spectra without REF is the spectra during injection.

Acoustic injection
We injected sound with a speaker.
Comb wave at 9.2 Hz and filtered white noise (30 - 500 Hz) were injected.
In both cases, we could see excess in Michelson sensitivity.
This is not so good although current sensitivity may not be limitted by this noise.
However, somehow there are not large coherence.
This may mean there is a non-linear coupling path.
The spectrum in comb wave at 23 Hz are shown as follows.
(K1:PEM-IY0_SENSOR4_OUT_DQ is magnetometer sensor signal in "Pa" unit and K1:CAL-CS_PROC_C00_DISPLACEMENT_DQ is Michelson signal in "nm" unit.)
REF13 and REF4 are spectra without injection and spectra without REF is the spectra during injection.

Impulse hummer injection
We hit some places of BS chamber with implusse hummer.
During this test (May 1st, 15:30-17:00 (JST)), the Michelson got down several times due to our impluse hummering.
Although we should analyze by our code (not in diaggui) to show the plot, there were excess when we hit the chamber.

Sensors unintallation
Plase note that, for the next PEM injection at Yend tomorrow, all sensors installed in klog4871 are uninstalled.
In other words, there is no sensors around BS now.

Images attached to this report
Comments to this report:
koji.nagano - 23:00 Wednesday 02 May 2018 (4934) Print this report

Another report about switch off test.

We performed a kind of switch off test of clean filters.
In the beginning, all filters were turned on.
We turned off 3/4 of clean filters on the ceiling of BS/PR2 booth for about 10 minutes.
(Miyoki-san asked us to keep 1/4 clean filters on.)
However, there is no change in strain spectrum.

After this test, we recovered the initial state, i.e. turned on all filters again.

koji.nagano - 23:06 Wednesday 02 May 2018 (4935) Print this report

Corrections of two typos

In acoustic injection, the comb signal was 23 Hz, not 9.2 Hz.
"Comb wave at 9.2 Hz and filtered white noise (30 - 500 Hz) were injected." --> "Comb wave at 23 Hz and filtered white noise (30 - 500 Hz) were injected."

And the date of hummering test is May 2nd (JST, today), not May 1st.
"During this test (May 1st, 15:30-17:00 (JST)), the Michelson got down several times due to our impluse hummering." --> "During this test (May 2nd, 15:30-17:00 (JST)), the Michelson got down several times due to our impluse hummering."

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