good vibrations
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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
E. Brost 18/6/09
CHESS & CHESS & LEPPLEPP
Collecting Data
ADC
Amplifier
AccelerometerWater flow
Laptop
10V/g
E. Brost 18/6/09
CHESS & CHESS & LEPPLEPP
Software
• Windowing: Blackman• Sample frequency: 2500 Hz• 8192 samples• Range: 0 - 400 Hz• Amplifier gain: 1000
• Performs FFT!
(Software deigned by Peter Revesz)
E. Brost 18/6/09
CHESS & CHESS & LEPPLEPP
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
E. Brost 18/6/09
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
E. Brost 18/6/09
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
E. Brost 18/6/09
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
E. Brost 18/6/09
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).
E. Brost 18/6/09
CHESS & CHESS & LEPPLEPP
Backup Slides
E. Brost 18/6/09
CHESS & CHESS & LEPPLEPP
Windowing (Before)
square
E. Brost 18/6/09
CHESS & CHESS & LEPPLEPP
Windowing (After)
Bartlett
Hanning Hamming
Blackman
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