1. LA ACES Neutron Detector (NeD)
Team Members: Ravi Chimmalgi
Robert Giglio
Shiloh Meyers
Bradley Wood
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2. Cosmic Rays: Supernova Debris
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Louisiana State University Physics and Astronomy

3. Cosmic Rays: Supernova Debris Cont
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4. Cosmic Rays: Coming to Earth
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Louisiana State University Physics and Astronomy

5. Cosmic Rays: Cosmic Shower and Neutron Production
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Louisiana State University Physics and Astronomy

6. Neutron Flux as Measured Aboard High Altitude Plane
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7. Measuring Neutron Flux in Atmosphere: Science Goals
Measure neutron flux as a function of altitude.
Differentiate neutrons from other interacting particles.
Create a graphical representation to present neutron flux versus altitude.
Give a definite statement on the safety issues present for airline passengers from the data found
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Louisiana State University Physics and Astronomy

8. Measuring Neutron Flux in Atmosphere: Scientific Requirements
Need to record at least one data point every 10 minutes, or an average of every ft (3.048 km) in order to reproduce the accuracy of previously observed data plots
Payload instrumentation must function for at least 4 hrs
Payload instrumentation must function at pressures as low as 10 mBars
Payload instrumentation must function at atmospheric temperatures as low as -60 degrees Celsius
Need to make measurements in altitude range of airline traffic (30000ft ft).
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9. Measuring Neutrons at High Altitudes: Conditions
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10. Altitude vs Temperature
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11. Measuring Neutrons at High Altitudes: Detector
PMT
Scintillation Plastic
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12. Detector Continued: Neutron Scatter
1 MeV
~500 keV to photons
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13. Detector Continued: Neutron Absorption
Alpha Deposition ~2.8 MeV
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Louisiana State University Physics and Astronomy

14. Previous Data At Palestine, Texas
Ground = .002 neutrons cm^-2/s (10keV – 10 MeV)
Max Balloon Altitude = .04 neutrons cm^-2/s ( MeV)
Based on
D. J. Forest and E. L. Chupp (1968). Upper Limit for the Solar Neutron Flux in the Energy Interval MeV. Kluwer Academic Publishers.
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15. Overview of electronics
Photomultiplier & boron-doped scintillator used
Produced By LA ACES Team F. N. H. S.
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Louisiana State University Physics and Astronomy

16. Light emitted by scintillator
How the PMT works
Light emitted by scintillator
PMT detects light & sends pulse to circuit
Produced By LA ACES Team F. N. H. S.
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Louisiana State University Physics and Astronomy

17. Timing the Windows Pulses specific times apart
Circuit detects first pulse, closes window for 150ns
Window opened
for 20us
Produced By LA ACES Team F. N. H. S.
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18. Electronics block diagram
Produced By LA ACES Team F. N. H. S.
Louisiana State University Physics and Astronomy
Louisiana State University Physics and Astronomy

19. Payload Overview Control Circuitry Sensor System Batteries & Holder
SolidWorks® Model of Mechanical Payload
Control
Circuitry
Sensor
System
Batteries & Holder
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20. Insert (Front-side) Photo of Insert
Title, caption – vertical orientation
Photo of Insert
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21. Insert (Back-side)
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22. Weight PMT/ Scintillator sensor neutron detectors >2kg (2000g)
Our Total Weight: ~1100g
Box
230 g
Circuits
190 g
Insert
90 g
Power & Cables
210 g
PMT
280 g
Misc.
100g
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23. Three different programs: pre-flight, on- flight and post-flight.
Software
Three different programs: pre-flight, on- flight and post-flight.
Fail-Safe mechanism
Sample rate = 10 sec
Each data point = 13 bytes
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Louisiana State University Physics and Astronomy

24. Pre-flight Program
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25. On-flight Program
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26. Post-flight Program
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27. Altitude readings from the GPS. Data analysis.
Flight Data Handling
Used Term232 and Excel.
Altitude readings from the GPS.
Data analysis.
- Neutron Count vs Altitude
- Particle Count vs Altitude
- Temperature vs Time
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Louisiana State University Physics and Astronomy

28. Procedure of Data Analysis
Took ground level counts in Palestine
Integrate data in 10 second intervals versus altitude
Integrate data in 5 minute intervals
Apply error deviation using following Poisson equations
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Louisiana State University Physics and Astronomy

29. Ground Count Comparisons
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30. Measured Neutron Flux vs Altitude (10 Sec)
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31. Measured Neutron Flux vs Altitude (5 min)
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32. Procedure of Data Analysis Cont
Compare data to previously recorded data
Compare data to neutron radiation levels for biological organisms
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Louisiana State University Physics and Astronomy

33. Predicted Neutron Flux vs Altitude
Predicted neutron flux as a function of altitude F. N. H. S.
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34. Measured Neutron Counts vs Altitude (5 min)
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35. We Detected a Neutron Calibration Source

36. We Detected a Neutron Calibration Source

37. We Detected a Neutron Calibration Source

38. Predicted Charged Particle Flux
Predicted measurements of cosmic ray flux given by LA ACE’s experiment FRED.
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39. Measured Charged Particle Flux
Charged Particle Counts
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40. Atmospheric Temperature
Predicted measurements of temperature given by LA ACE’s experiment TIC.
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41. Measured Internal Temperature vs Time
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42. Biological Radiation in Equivalent Dosages
Equivalent dose measured in Sieverts
1 Sievert causes nauseation
2 Sieverts causes hair loss
6 Sieverts kills
Conversion equation: DE = R(E) φ
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43. Neutron Dose vs Altitude
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44. Charged Particle Counts Over Total Flight
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45. Charged Particle Counts At Launch
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46. Thank you Jim Adams and Mark Christl at Marshal Space Center
Dr. Erno Sajo
Dr. Jeff Blackmon
Columbia Scientific Ballooning Facility