integration of a clover detector with the necessary electronics and computer program to utilize the...
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Integration of a Clover Detector with the Integration of a Clover Detector with the necessary electronics and computer program necessary electronics and computer program
to utilize the ADDBACK methodto utilize the ADDBACK method
An SP496 and Capstone Research Project
Midshipman First Class Jack Hathaway
Advised byAssistant Professor Daryl Hartley, Ph.D.
Co60
Energy
Unstable Co60
1173 γ-ray
1332 γ-ray
Stable Ni60
Time
Emitted Beta Particle
Emitted Gamma rays
Unstable Ni60Beta Decay
So how do we ‘see’ all of this happening? What kind of detector do we need?
When my advisor was a student…
Bell bottoms were cool…
The Beetles first appeared on stage…
…and nuclear physicists used Sodium Iodide (NaI) Detectors…
High Density = Great Efficiency
Poor Energy Resolution from detection system
While I was busy watching Transformers…
Nuclear physicists developed Germanium (Ge) Crystal Detectors…
Low Density = Low Efficiency
Great Energy Resolution from detection system
Low Density = Low Efficiency
Great Energy Resolution from detection system
Can we have the best of both?
High efficiency
and
good resolution?
Clover detectorClover detectorAn array of four Germanium Crystals, physically and electronically independent
Clover Detector
Source Location
25 cm
Anode
Cathode
The Basic Electronics:
Spec AmpKMAX
Program
Channel Number
NumberOf
Counts
Crystal 1
Channel Number
NumberOf
Counts
Crystal 3
Channel Number
NumberOf
Counts
Crystal 2
Channel Number
NumberOf
Counts
Crystal 4
Channel Number
Crystal 1 0
Crystal 2 600
Crystal 3 0
Crystal 4 0
ADC
The KMAX program displayed 5 counts, The KMAX program displayed 5 counts, but there were only 3 Events….but there were only 3 Events….
Were there 5 gamma rays or only 3?Were there 5 gamma rays or only 3?
Mission:Utilize the Clover Detector as an array rather
than four single detectors to give the researcher the best data possible
Solution:Integrate the Clover Detector into the necessary electronics and create a
computer program to utilize the ADDBACK Method
What is ADDBACK?
Addback Flash created by Dave Campbell, Florida State University
Coding ADDBACKComputer Input
Channel Number
Crystal 1 0
Crystal 2 600
Crystal 3 0
Crystal 4 0
Define an event
Step 1:
Event 1
Each event corresponds to a single gamma ray interacting with the detector.
One Gamma ray = One Event = One Coincidence Window
Output group 1
Output group 2
Fast AmpLogic ‘OR’
Gate
Spec Amp
Analog to Digital Converter
1 2 3 4
Inputs
Output to Computer
Step 2: Creating an electronic Coincidence Window
Event 1 Channel Number
Crystal 1 600
Crystal 2 0
Crystal 3 400
Crystal 4 200
ADC Gate
GateDelay
Generator
Step 3: Applying calibrations
Event 1 Channel Number
Crystal 1 600
Crystal 2 0
Crystal 3 400
Crystal 4 200
Channel Number
Crystal 2
Channel Number
Crystal 1Counts
Channel Number
Crystal 3
Channel Number
Crystal 4
Counts
Counts
Counts
Energy
Energy
Energy
Energy
Step 4: Executing ADDBACK
ADDBACK = 560 + 0 + 412 + 201 = 1173
Event 1 Channel Number Energy
Crystal 1 600 560
Crystal 2 0 0
Crystal 3 400 412
Crystal 4 200 201
Event 1 1173
Event 2 1332
Event 3 1173
Event 4 997
TotalsADDBACK
Event 1 560, 412, 201
Event 2 1332
Event 3 1173
Event 4 746, 251
Separate Crystals
Event 2 Channel Number Energy
Crystal 1 1350 1332
Crystal 2 0 0
Crystal 3 0 0
Crystal 4 0 0
1332 + 0 + 0 + 0 = 1332
Event 3 Channel Number Energy
Crystal 1 0 0
Crystal 2 0 0
Crystal 3 1150 1173
Crystal 4 0 0
0 + 0 + 1173 + 0 = 1173
Event 4 Channel Number Energy
Crystal 1 0 0
Crystal 2 800 746
Crystal 3 0 0
Crystal 4 210 251
0 + 746 + 0 + 251 = 997
3:1 ratio (actual 25%) 2:5 ratio (actual 14%)Peak toBackground
Results
Results
- Longer Runs
- Proton Resonance
- Polarization
Future Goals
AcknowledgementsAcknowledgements
Advisor: Assistant Professor Daryl Hartley, Ph.D.
Witty quips and technical advice: Professor Jeff Vanhoy, Ph.D.
Stunts and Modeling: MIDN 1/C Drew Barker, roommate
125 250 400 650
Scratch-work slide
Background
Detector pictures?
Clover Picture
The Basics:
Spec Amp ADCKMAX
Program
Channel Number
NumberOf
Counts
Crystal 1
Channel Number
NumberOf
Counts
Crystal 3
Channel Number
NumberOf
Counts
Crystal 2
Channel Number
NumberOf
Counts
Crystal 4
Coding ADDBACK
Event 1Event 1Event 2Event 2Event 3Event 3
1 Count
1 Count 1 Count
1 Count2 CountsThe KMAX program displayed 5 counts, The KMAX program displayed 5 counts,
but there were only 3 Events….but there were only 3 Events….
Were there 5 gamma rays or only 3?Were there 5 gamma rays or only 3?
Pre-Amp
Double outputs, same signal from each crystal
Interior to the Clover Detector
What is a Coincidence Window?
Ekg thingermabober of science!
Input
32 microseconds
ADCGate
GateDelay
Generator
Output
Question slide on the PMT NaI detectors