“something about ground vibration measurements”
DESCRIPTION
“something about ground vibration measurements”. K.Artoos Slides from M.Guinchard , Ch. Collette, M. Sylte. Equipment PSD Integrated RMS displacement Technical noise sources: model + some examples Sensor noise Coherence measurements. Ground vibration measurements. Equipment and settings. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/1.jpg)
CLIC-ACE5_04.02.2010 K.Artoos 1
“something about ground vibration measurements”
K.ArtoosSlides from M.Guinchard, Ch. Collette, M. Sylte
![Page 2: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/2.jpg)
2
Ground vibration measurements
CLIC-ACE5_04.02.2010 K.Artoos
EquipmentPSDIntegrated RMS displacementTechnical noise sources: model + some examplesSensor noiseCoherence measurements
![Page 3: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/3.jpg)
CLIC-ACE5_04.02.2010 K.Artoos 3
Equipment and settings• Vibrations sensors
Type Supplier Type Sensitivity Freq. Range Axes
Geophones GURALP CMG 6T 2000 V/m/s 30s to 100Hz NS, EW, V
Seismic accelerometers
PCB 393B31 10 V/g 0.1 to 200Hz V
ENDEVCO 86 10 V/g 0.1 to 200Hz V
• Data acquisition system– Spectrum analyser with 16 channels– 24 bits on 10mV for the lowest dynamic range– Sampling frequency up to 200kHz– Noise level DAC< 1 μV– Software for signal treatment (FFT, PSD, Filtering, etc…)
Version:MKII
Sampling rate 1024HzMeasurement Length 1440sBlock length 64sOverlap 66,7%Window function HanningAveraging Linear
Parameters:
M. Guinchard, M. Sylte
![Page 4: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/4.jpg)
CLIC-ACE5_04.02.2010 K.Artoos 4
Power Spectral Density
M. Guinchard, M. Sylte
![Page 5: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/5.jpg)
5
Vertical
1nm
5nm
Lateral
M. Sylte, M. Guinchard
Measured on FLOOR
2 nm
CLIC-ACE5_04.02.2010 K.Artoos
![Page 6: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/6.jpg)
6
Additional technical noise:
Reference
Local excitations: modelVertical ground motion
Reference
6CLIC-ACE5_04.02.2010 K.ArtoosCh. Collette
![Page 7: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/7.jpg)
C. Collette, ILC-CLIC LET Beam Dynamics Workshop (23-25 June 2009)
7
Local excitations Lateral ground motion
Additional technical noise:
Ref. :
Reference
Reference
![Page 8: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/8.jpg)
CLIC-ACE5_04.02.2010 K.Artoos 8
Support amplifications
CLEX girder
Mineral cast girder(PSI)
![Page 9: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/9.jpg)
CLIC-ACE5_04.02.2010 K.Artoos 9
Color map LHC tunnel measurements
![Page 10: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/10.jpg)
CLIC-ACE5_04.02.2010 K.Artoos 10
Color map LHC tunnel measurements
![Page 11: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/11.jpg)
CLIC-ACE5_04.02.2010 K.Artoos 11
Example influence ventilation CLEX
![Page 12: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/12.jpg)
CLIC-ACE5_04.02.2010 K.Artoos 12
Two geophones side by side:
Sensor noise
where Signal to noise spectrum ratio:
C. Montag. PhD thesis, Hamburg University, 1996.
Prepared by C. Collette
![Page 13: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/13.jpg)
C. Hauviller 13ACE090527
Sensor noise detectionPrepared by C. Collette
![Page 14: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/14.jpg)
CLIC-ACE5_04.02.2010 K.Artoos 14
Sensor Noise
At high frequency, the sensor noise increases linearly with signal level
C. Collette, M. Sylte
![Page 15: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/15.jpg)
CLIC-ACE5_04.02.2010 K.Artoos 15
Sensor Noise
Seismic accelerometers(Brüel & KjærTM type 8340)
![Page 16: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/16.jpg)
CLIC-ACE5_04.02.2010 K.Artoos 16
Use of the seismometers– CMG-6T Guralp seismometers
PSI + Cesr TA: Influence from magnetic fields and radiation:
The sensors were placed about 2 m from the quadrupole. No effect was observed from the magnetic field. The effect from radiation needs more investigation.
Influence from thermal conditions: Long settling time noise reductioncover
![Page 17: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/17.jpg)
Guralp CMG 40T2*800Vs/m
30 s -50 Hz
x,y,z
ENDEVCO 86PCB 393B31
2 Muller-BBMMKII Analyzers
1 km of optical fibre for synchronisation + timingand Data Transfer
Parameters
Sampling rate256 Hz
Block duration64 s
Average Lin – 50Overlap66.7 %
Ground motion measurements : Coherence length
![Page 18: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/18.jpg)
Guralp CMG 40T2*800Vs/m
30 s -50 Hz
Ground motion measurements : Coherence length
Specific features : Synchronous measurements
Phase error < 0.01 deg on the frequency range
![Page 19: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/19.jpg)
C. Collette, ILC-CLIC LET Beam Dynamics Workshop (23-25 June 2009)
19
d=960 m; filtered between 0.08 Hz and 0.5 Hz
- Correlation in the low frequency range- Similar amplitudes in all directions
3D coherences
or ?
![Page 20: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/20.jpg)
Coherence measurements LHC tunnel
06m7m10m
![Page 21: “something about ground vibration measurements”](https://reader035.vdocuments.net/reader035/viewer/2022062310/5681642d550346895dd5f27d/html5/thumbnails/21.jpg)
Coherence measurements Surface Building 180