Integration of a Clover Detector with the necessary electronics and computer program

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