LCLS-II Vibration Study – RSY, Seismometer Measurements

LCLS-II Vibration Study – RSY, Seismometer Measurements

Georg Gassner, April10th, 2013

Construction Equipment Run – Sensor Placement

Slide 2

13

1

2

3

4

57

68

6

6

9

10

11

12

14

15

QEM

QUM

QT4x

… Jack Hammer … Back Hoe … Concrete Vibrator … Plate Compactor … Core Drilling … Geophone

Construction Equipment Run – Time Table

Task # Task DescriptionStart Time

Duration [minutes]

1 Jack Hammer 8:00 30

2 Back Hoe – scraping asphalt paving 8:30 15

3 Back Hoe – pounding side of hill 8:45 15

4 Concrete Vibrator 9:00 30

5 Plate Compactor 9:30 30

6 Core Drilling – various locations 10:00 30

7 Back Hoe 10:30 30

8 Jack Hammer 11:00 30

Break 11:30 90

9 Jack Hammer 13:00 30

10 Back Hoe – scraping paving 13:30 30

11 Plate Compactor 14:00 30

12 Concrete Vibrator 14:30 30

13 Jack Hammer 15:00 30

14 Core Drilling 15:30 30

15 Back Hoe 16:00 30

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Seismometer Sensors - L4C

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Sercel L4C Sensors

Sensitivity: 629 Volts / m/sNatural Frequency: ~1Hz

Horizontal sensors on top of:• QT41 QT42 and QT43• QEM1 and QEM2• QUM1 and QUM2

Vertical sensors on top of:• QT41, QT42 and QUM2

Data Acquisition Systems

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• Sampling rate: 4096Hz

• System 1 (2 minute datasets):

• National Instruments Model SCC-68 (16 Bits)) • Horizontal sensors

- QT41, QEM2, QUM1 and QUM2

• System 2 (continuous):

• NI Model 9234 (24 Bit) in NI-cRIO9076- All other sensors

Background Noise – One Week of Data

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Integrated Motion – Horizontal

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Bac

k H

oe

Bac

k H

oe

Bac

k H

oe

Bac

k H

oe

Pla

te C

ompa

ctor

Pla

te C

ompa

ctor

Integrated Motion – Vertical

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Bac

k H

oe

Bac

k H

oe

Bac

k H

oe

Bac

k H

oe

Pla

te C

ompa

ctor

Pla

te C

ompa

ctor

Statistical Distribution

• 30 minutes of data split into 10 second intervals

• FFT of all 10 second intervals

• Sorting of values

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Results – PSD Back Hoe

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Location Main Freq. Side Band

QT41 horizontal 31 Hz 24 Hz

QT42 horizontal 36 Hz 26 Hz

QT43 horizontal 33 Hz 30 Hz

QEM1 horizontal 29 Hz

QEM2 horizontal 33 Hz 30 Hz

QUM1 horizontal 32.5 Hz 38 Hz

QUM2 horizontal 30.5 Hz 34 Hz

Results – PSD QT41H & QT42H

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Results – PSD QEM1H & QEM2H

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Results – Position Back Hoe

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14

Summary and Outlook

• Back Hoe has biggest influence of the construction

equipment tested

• Continuous vibration during Back Hoe operation of

• +/- 0.2µm if back hoe is nearby (<20m)

• At 60m distance from Back Hoe operation

• +/- 0.1µm at QUM and QEM magnets

• Vibration de-correlates quickly after initial trigger

• Outlook:- Observing x-ray beam while artificially vibrating M1H