LA ACES Neutron Detector (NeD) Team Members: Ravi Chimmalgi Robert Giglio Shiloh Meyers Bradley Wood...
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Transcript of LA ACES Neutron Detector (NeD) Team Members: Ravi Chimmalgi Robert Giglio Shiloh Meyers Bradley Wood...
LA ACESLA ACESNeutron Detector (NeD)Neutron Detector (NeD)
Team Members: Ravi Chimmalgi
Robert Giglio
Shiloh Meyers
Bradley Wood
Louisiana State University LaAces Amateur Balloon Flight Program
Cosmic Rays: Supernova DebrisCosmic Rays: Supernova Debris
http://upload.wikimedia.org/wikipedia/commons/thumb/4/43/Supernova-1987a.jpg/660px-Supernova-1987a.jpg
Louisiana State University LaAces Amateur Balloon Flight Program
http://auger.cnrs.fr/presse/0197swordy2a.gif
Cosmic Rays: Supernova Debris ContCosmic Rays: Supernova Debris Cont
Louisiana State University LaAces Amateur Balloon Flight Program
Cosmic Rays: Coming to EarthCosmic Rays: Coming to Earth
http://www.astroparticlephysics.nl/cosmic_rays.jpg
Louisiana State University LaAces Amateur Balloon Flight Program
Cosmic Rays: Cosmic Shower and Cosmic Rays: Cosmic Shower and Neutron ProductionNeutron Production
http://neutronm.bartol.udel.edu/catch/cr2b.gifLouisiana State University LaAces Amateur Balloon Flight Program
Neutron Flux as Measured Aboard High Neutron Flux as Measured Aboard High Altitude PlaneAltitude Plane
Louisiana State University LaAces Amateur Balloon Flight Program
Measuring Neutron Flux in Atmosphere: Measuring Neutron Flux in Atmosphere: Science GoalsScience 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
Louisiana State University LaAces Amateur Balloon Flight Program
Measuring Neutron Flux in Atmosphere: Measuring Neutron Flux in Atmosphere: Scientific RequirementsScientific Requirements
• Need to record at least one data point every 10 minutes, or an average of every 10000 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-40000ft).
Louisiana State University LaAces Amateur Balloon Flight Program
Measuring Neutrons at High Altitudes: Measuring Neutrons at High Altitudes: ConditionsConditions
http://csep10.phys.utk.edu/astr161/lect/earth/atmosphere.gif
Louisiana State University LaAces Amateur Balloon Flight Program
Altitude vs TemperatureAltitude vs Temperature
http://www.seungjoo.net/projects/may2006/image2/clip_image039.jpgLouisiana State University LaAces Amateur Balloon Flight Program
Measuring Neutrons at High Altitudes: Measuring Neutrons at High Altitudes: DetectorDetector
http://www.sphere.bc.ca/test/tubes/252-rca-6655a.jpghttp://www.apace-science.com/eljen/images/plastic.jpg
PMT Scintillation Plastic
Louisiana State University LaAces Amateur Balloon Flight Program
Detector Continued: Neutron ScatterDetector Continued: Neutron Scatter
http://knowledgepublications.com/doe/images/DOE_Nuclear_Elastic_Scattering.gif
~500 keV to photons
1 MeV
Louisiana State University LaAces Amateur Balloon Flight Program
Detector Continued: Neutron Absorption Detector Continued: Neutron Absorption
Alpha Deposition ~2.8 MeV
Louisiana State University LaAces Amateur Balloon Flight Program
Previous Data At Palestine, TexasPrevious Data At Palestine, Texas
Ground = .002 neutrons cm^-2/s (10keV – 10 MeV)
Max Balloon Altitude = .04 neutrons cm^-2/s (20-120 MeV)
Based on D. J. Forest and E. L. Chupp (1968). Upper
Limit for the Solar Neutron Flux in the Energy Interval 20-120 MeV. Kluwer Academic Publishers.
Louisiana State University LaAces Amateur Balloon Flight Program
Overview of electronicsOverview of electronics
Photomultiplier & boron-doped scintillator used
Produced By LA ACES Team F. N. H. S.
Louisiana State University LaAces Amateur Balloon Flight Program
How the PMT worksHow the PMT works
Light emitted by scintillatorPMT detects light & sends pulse
to circuit
Produced By LA ACES Team F. N. H. S.
Louisiana State University LaAces Amateur Balloon Flight Program
Timing the WindowsTiming the Windows
Pulses specific times apartCircuit detects first pulse, closes window for
150nsWindow opened
for 20us
Produced By LA ACES Team F. N. H. S.
Louisiana State University LaAces Amateur Balloon Flight Program
Louisiana State University Physics and Astronomy
Electronics block diagramElectronics block diagram
Produced By LA ACES Team F. N. H. S.
Payload OverviewPayload OverviewSolidWorks® Model of Mechanical Payload
Sensor System
Sensor System
ControlControl CircuitryCircuitry
ControlControl CircuitryCircuitry
Batteries & HolderBatteries & Holder
Louisiana State University LaAces Amateur Balloon Flight Program
Insert (Front-side)Insert (Front-side)
Photo of Insert
Louisiana State University LaAces Amateur Balloon Flight Program
Insert (Back-side)Insert (Back-side)
Louisiana State University LaAces Amateur Balloon Flight Program
• PMT/ Scintillator sensor neutron detectors >2kg (2000g)
• Our Total Weight: ~1100g
WeightWeight
Box 230 g
Circuits 190 g
Insert 90 g
Power & Cables 210 g
PMT 280 g
Misc. 100g
Louisiana State University LaAces Amateur Balloon Flight Program
SoftwareSoftware
Three different programs: pre-flight, on-flight and post-flight.
Fail-Safe mechanismSample rate = 10 secEach data point = 13 bytes
Louisiana State University LaAces Amateur Balloon Flight Program
Pre-flight ProgramPre-flight Program
START ENDFOR ADDR =
0 to $7FFFof EEPROM
STORE$FF
INITIALIZE realtime clock by
writing thetime to the
correspondingaddresses in
the clockregister.
Louisiana State University LaAces Amateur Balloon Flight Program
On-flight ProgramOn-flight ProgramSTART
END
Set countersto event
counter mode
ADDR = ADDR + 13
Enoughmemory?
NO
YES
ADDR = 0
READEEPROM
IS EEPROM= $FF ?
ADDR = ADDR + 1
START counters
WAIT 10 sec
STOP counters
READcounters,time andtemperat
ure
STORE thedata
NO
YES
Louisiana State University LaAces Amateur Balloon Flight Program
Post-flight ProgramPost-flight Program
START ENDFOR Addr = 0to $7fff
READ & PRINTAddr.
New line
ISADDR>=$7fff
?
YES
NO
Addr = Addr +13
FOR x=1 to 13
Louisiana State University LaAces Amateur Balloon Flight Program
Louisiana State University Physics and Astronomy
Flight Data HandlingFlight Data Handling
Used Term232 and Excel.Altitude readings from the GPS. Data analysis.
- Neutron Count vs Altitude - Particle Count vs Altitude - Temperature vs Time
Louisiana State University Physics and Astronomy
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
Procedure of Data AnalysisProcedure of Data Analysis
Ground Count ComparisonsGround Count Comparisons
Louisiana State University LaAces Amateur Balloon Flight Program
Measured Neutron Flux vs Altitude (10 Measured Neutron Flux vs Altitude (10 Sec)Sec)
Louisiana State University LaAces Amateur Balloon Flight Program
Measured Neutron Flux vs Altitude (5 Measured Neutron Flux vs Altitude (5 min)min)
Louisiana State University LaAces Amateur Balloon Flight Program
Louisiana State University Physics and Astronomy
Compare data to previously recorded data
Compare data to neutron radiation levels for biological organisms
Procedure of Data Analysis ContProcedure of Data Analysis Cont
Predicted Neutron Flux vs AltitudePredicted Neutron Flux vs Altitude
Predicted neutron flux as a function
of altitude F. N. H. S.Louisiana State University LaAces Amateur Balloon Flight Program
Measured Neutron Counts vs Altitude (5 Measured Neutron Counts vs Altitude (5 min)min)
Louisiana State University LaAces Amateur Balloon Flight Program
We Detected a Neutron Calibration Source
We Detected a Neutron Calibration Source
We Detected a Neutron Calibration Source
Californium Source
0
10
20
30
40
50
60
0:20:10 0:21:36 0:23:02 0:24:29 0:25:55 0:27:22 0:28:48 0:30:14 0:31:41 0:33:07
Time (s)
Co
un
ts
Predicted Charged Particle FluxPredicted Charged Particle Flux
Predicted measurements of cosmic ray flux given by LA ACE’s experiment FRED.
Louisiana State University LaAces Amateur Balloon Flight Program
Measured Charged Particle FluxMeasured Charged Particle Flux
Louisiana State University LaAces Amateur Balloon Flight Program
Atmospheric TemperatureAtmospheric Temperature
Louisiana State University LaAces Amateur Balloon Flight Program
Predicted measurements of temperature given by LA ACE’s experiment TIC.
Measured Internal Temperature vs TimeMeasured Internal Temperature vs Time
Louisiana State University LaAces Amateur Balloon Flight Program
Biological Radiation in Equivalent Biological Radiation in Equivalent DosagesDosages
Equivalent dose measured in Sieverts
1 Sievert causes nauseation 2 Sieverts causes hair loss6 Sieverts kills
Conversion equation: DE = R(E) φ
Louisiana State University LaAces Amateur Balloon Flight Program
Neutron Dose vs AltitudeNeutron Dose vs Altitude
Louisiana State University LaAces Amateur Balloon Flight Program
Charged Particle Counts Over Total FlightCharged Particle Counts Over Total Flight
Louisiana State University LaAces Amateur Balloon Flight Program
Charged Particle Counts At LaunchCharged Particle Counts At Launch
Louisiana State University LaAces Amateur Balloon Flight Program
Launch Particle Counts
0
10
20
30
40
50
60
70
300 600 900 1200 1500 1800 2100 2400 2700 3000 3300 3600 3900 4200 4500
Altitude (feet)
Pa
rtic
le C
ou
nts
High Threshold
Low Threshold
Thank you
Jim Adams and Mark Christl at Marshal Space Center
Dr. Erno SajoDr. Jeff BlackmonColumbia Scientific Ballooning Facility