infrared spectroscope for electron bunch length measurement: heat sensor parameters analysis
DESCRIPTION
Infrared spectroscope for electron bunch length measurement: Heat sensor parameters Analysis. Gilles Dongmo – M. SULI Presentation August 11, 2011. The detector. The detector used for the project is a piezoelectric detector made of Lead Zirconate Titanate (PZT) - PowerPoint PPT PresentationTRANSCRIPT
Infrared spectroscope for electron bunch length measurement:
Heat sensor parameters Analysis
Gilles Dongmo – M.SULI Presentation August 11, 2011
The detector
The detector used for the project is a piezoelectric detector made of Lead Zirconate Titanate (PZT)
128 pixels arranged over 14.3 mm
The printed board circuit
The detector is mounted to a printed circuit board
Pin 3 of the synchronization connector out puts a pulse
The connector TP3 out puts the signal response of the detector
Power connector USB connector
Synchronization connector (pin 3) Sensor connected
Output detector signal
The initial data collected
0 20 40 60 80 100 120-10
90
190
290
390
490
590
690
790
890
RMS signal and signal brightness per pixel at 210Hz
rms databrightness data
background rms
pixel number
brig
thne
ss
The detector is lit at the middle pixels
maybe the detector was sending out an inverted signal.
Pixels 68 and 95 are dead.
What type of noise do we have to deal with?
0 50 100 150 200 2500
100
200
300
400
500
600
700
800
900
rms data and average brightness for the whole frequency range
rms brightness
frequencies (Hz)
brig
htne
ss (u
V)
Data were recorded for frequencies up to 250 Hz
The signal to noise ratio was found to be high
We get an average signal to noise ratio of 43.3
The detector is not very sensitive to the room’s light and other background noise.
Data collectionThe read rectangles
represent the maximum and minimum values averaged over 12 sampling
The green line is the current reading.
Some pixels are dead.How is the software using
the raw data?
Dead pixel
The AC-Coupling issue
The next step was to try to figure out what type of data were actually collected by the detector which meant we had to understand how the data were collected.
We were able to write a program replicating the data received by the software. The algorithm they used did not seem to present any issue if the data the detector was outputting was the light intensity read by it when the light was on and off
Tape at the middle of the detector
0 20 40 60 80 100 120 1400
5
10
15
20
25
220Hz with centered tape data comparison
software data
rms
pixel
max
imum
inte
nsity
(mv)
0 20 40 60 80 100 120 1400
5
10
15
20
25
240Hz with centered tape data comparison
software datarms
pixel
max
imum
inte
nsity
(mv)
Dead pixel reading
Intensity of the signal
0 20 40 60 80 100 120 1400
5
10
15
20
25
240Hz with centered tape data comparison
software datarms
pixel
max
imum
inte
nsity
(mv)
0 20 40 60 80 100 120 140
-80
-60
-40
-20
0
20
40
60
80
100
120
140
160
LED rate of 240Hz data compar-ison
software datarms
pixel
max
imum
inte
nsity
(mv)
Detector’s response time
Generated signal and integration time. On this graph from the detector’s user’s manual, the integration time covers most of the signal period both the on and off phase.
Dead time
The integration time dataExperimental integration time Calculated integration time
frequencies (Hz) VDR time (us) delay (us)
240 375 0
240 400 74
240 646 258
230 800 350
220 1000 494
210 1200 634
201 1400 1270
197 1500 over
129 4000 over
frequencies (Hz) VDR time (us) integration time (us)
240 375 3788.666667
240 400 3763.666667
240 646 3517.666667
230 800 3544.826087
220 1000 3542.454545
210 1200 3558.904762
201 1400 3572.124378
197 1500 3573.142132
129 4000 3748.937984
Comparison of the integration times
120 140 160 180 200 220 240 2600
500
1000
1500
2000
2500
3000
3500
4000
Comparison of the integration time and delay time
integration timedelay time
frequencies (Hz)
time
(us)
The plot shows the calculated integration time is very constant over this range frequencies.
The delay drops with frequency
The equipment setup
Single cell detector and Infrared laser
Single cell piezoelectric detector.
Sensitivity calculated to be 1.34 micro-amps per watt.
This was done with the red HeNe laser.
Sensitivity calculationThe amount of power
generated by the laser was recorded using a power meter
The chopper wheel created the pulse
The lens focused the beam as much as possible
Current output determination
AcknowledgementsThis was done with the appreciated contribution of:
Josef Frisch Alan Fischer Kiel Williams Julie Cass
Mark Petree Georges Burgueno
Tonee Smith The Department of Energy
SLAC & SULI staff
Thank you!!