stefan hild s4 data workshop, hannover, may 2005 title 1 khz glitches in s4 max-planck-institut für...

Stefan Hild S4 Data Workshop, Hannover, May 2005

Title

1 kHz Glitches in S4

Max-Planck-Institut für Gravitationsphysik(Albert-Einstein-Institut)


GEO‘s sensitivity for last 20 days of S4

Peak sensitivity ‚drifted‘ during S4(much more than at other frequencies)


BLRMS of H(t) vs glitch rateH

(t)

BL

RM

S 9

90-1

000

Hz

Gli

tch

rate

700

-200

0

Hz

Found relation between glitchrate and peak sensitivity.


Spectra for good and bad time

Example times:

• high glitch rate 2005-03-22 06:10:00

• low glitch rate 2005-03-22 13:00:00

Glitches cause additional noise between 400 Hz and 1.3 kHz


Spectrograms of differential EP-PH

igh

gli

tch

rate

L

ow

gli

tch

rate

Glitches present in MI_diff_EP not an artifact from calibration process


Timeseries of 1kHz Glitches

Filtered with bandpass, 950 to 1050 Hz, 6th Order


Noise projections

1 kHz glitches can‘t be explained by our current set of noiseprojections


Gliches vs BLRMS @ 1 kHz


Timedomain distribution


SNR distribution


Number of pixels


Duration of bursts


Bandwidth of burst

Probably maximal bandwidth is limited to 400 Hz (strong lines 822 and 1266 Hz)


Time-delay between glitches


Periodicity of the glitches

Sometimes one can see a periodicity (5-10 times per hour) of the

glitchrate

Periodicity of 1.45 mHz


1.45 mHz in autoalignment signals

1.45 mHz 2*1.45 mHz


1.45 mHz

1.45 mHz in MC_AA rotation

2*1.45 mHz


Temperatures in the central building

1.45 mHz

2*1.45 mHz

2.3 mHz


2.3 mHz from air conditioning system

2.3 mHz is produced by the outdoor unit of central building‘s

airconditioning system

AC system usually dominates vertical seismic rms at the

central building


Temperatures in the central building

1.45 mHz

2*1.45 mHz

2.3 mHz from AC

1.45 and 2.9 mHz appear strongly in temperature of the laser bench


Periodicity of the glitches

Sometimes one can see a periodicity (5-10 times per hour) of the

glitchrate

Periodicity of 2.5 mHz


2.5 mHz in MPR alignment

2.5 mHz 2*2.5 mHz 3*2.5 mHz

1.45 mHz 2.9 mHz


2.5 mHz in MC2-AA

2.5 mHz 2*2.5 mHz 3*2.5 mHz


2.5 mHz in central building‘s temperatures

2.5 mHz

2.3 mHz


How to go on ??

• Is there any possibility to get vetoes for the 1 kHz Glitches ?

• Do we have to make vetoes for the 1 kHz Glitches ?

• How can we avoid such a problem in future?More time in front of a data run (???)

Some further effort is needed to investigate the Glitches and find their origin.

Analysis of GEO S4 data

Instrumental viewpoint

Future issues


How to attack the problem

„Thinking“:

Which hardware of GEO600 could cause glitches with these properties ? Coupling ? What experiments do we need to check a potential hypothesis?

Data analysis:

• Try to find a correlation between glitchrate during S4 and ???

• Compare detector status for good (low glitch rate) and bad time (high glitch rate). Anything different ?

• Maybe the periodicity leads us to origin of the glitches ?


HACR: Burst and glitch analysis

Take in 32 seconds of data

Subdevide this into subsegments of 32 ms (Overlab of 28 ms)

Windowing and FFT

Spectrogram (2-dim set of numbers / pixels)

Clustering

lk

kik tm

hk

kik tm

Triggers

km

k

ht

lt

= mean

= standard deviation

= high threshold = 25

= low threshold = 5

Index i = subsegmentIndex k = frequency bin

stefan hild s4 data workshop, hannover, may 2005 title 1 khz glitches in s4 max-planck-institut für...

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