E. Brost 18/6/09

CHESS & CHESS & LEPPLEPP

Good VibrationsVibration studies at CHESS

Elizabeth Brost

Mentor: Peter Revesz, Don Hartill

CLASSE Physics REU

June 18, 2009

E. Brost 18/6/09

CHESS & CHESS & LEPPLEPP

Outline

• Goals

• Experimental Setup

• Preliminary results

• Plans for the rest of the summer

E. Brost 18/6/09

CHESS & CHESS & LEPPLEPP

Goals

• Study the vibrations in:– F-Cave, F3 hutch

– Capillary puller

– CESR components

• Find out what’s causing the vibrations• Plan how to stop the vibrations

E. Brost 18/6/09

CHESS & CHESS & LEPPLEPP

Experimental Setup (F-Cave)

¾” copper coil

flow meter

me

accelerometer

water on/off

coil #11 (out)

coil #1 (in)

(Sol Gruner’s design for the experimental setup)

E. Brost 18/6/09

CHESS & CHESS & LEPPLEPP

Piezoelectric Accelerometer

Mass

Piezoelectric cantileverG

Voltage

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Collecting Data

ADC

Amplifier

AccelerometerWater flow

Laptop

10V/g

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Software

• Windowing: Blackman• Sample frequency: 2500 Hz• 8192 samples• Range: 0 - 400 Hz• Amplifier gain: 1000

• Performs FFT!

(Software deigned by Peter Revesz)

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A little bit of Digital Signal Processing

105Hz sine wave from a function generator

V(t)V(f)

V(t) V(f) g(f) A(f)

g(f) = C*V(f) (C = 9.9 V/g)

A(f) = - (1/ω2)g(f) (ω = 2πf)

FFT

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CHESS & CHESS & LEPPLEPP

Preliminary Results

0 50 100 150 200 250 300 350 4001E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1

Water on, sensor 731A

am

plit

ud

e (

mic

ron

s)frequency (Hz)

Concrete floor coil #1. bottom

0 50 100 150 200 250 300 350 4001E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1

Water off, sensor 731A

am

plit

ud

e (

mic

ron

s)

frequency (Hz)

Concrete floor coil #1, bottom

concrete floor vs. input coil

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CHESS & CHESS & LEPPLEPP

Preliminary Resultsinput coil – water on vs. water off

0 50 1001E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1

Coil #1, sensor 731A

am

plit

ud

e (

mic

ron

s)

frequency (Hz)

Water on Water off

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CHESS & CHESS & LEPPLEPP

Preliminary Results

0 50 100 150 200 250 300 350 4001E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1

Water OFF, top of coils

am

plit

ud

e (

mic

ron

s)

frequency (Hz)

coil #1 (in) coil #11 (out)

input coil vs. output coil

0 50 100 150 200 250 300 350 4001E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1

Water ON, top of coils

am

plit

ud

e (

mic

ron

s)

frequency (Hz)

coil #1 (in) coil #11 (out)

water out water in

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CHESS & CHESS & LEPPLEPP

Conclusions

• Water flow in the cooling coils is a significant source of vibrations, especially at low frequencies

• Constraining the coils helps to get rid of some

low-frequency vibrations

E. Brost 18/6/09

CHESS & CHESS & LEPPLEPP

Plans for the rest of the summer

• Continue vibration studies in the F-cave and in other areas of CHESS

• Identify the source of the vibrations• Stop the vibrations!!

E. Brost 18/6/09

CHESS & CHESS & LEPPLEPP

Acknowledgements

• Peter Revesz, Don Hartill

• Sol Gruner

• Richard Galik, Georg Hoffstaetter, Ernie Fontes, Lora Hine

• NSF

• Everyone at CHESS

E. Brost 18/6/09

CHESS & CHESS & LEPPLEPP

References

C. Mercer, “Acceleration, Velocity and Displacement Spectra

Omega Arithmetic,” Prosig Signal Processing Tutorials (2006).

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CHESS & CHESS & LEPPLEPP

Backup Slides

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CHESS & CHESS & LEPPLEPP

Windowing (Before)

square

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CHESS & CHESS & LEPPLEPP

Windowing (After)

Bartlett

Hanning Hamming

Blackman