NeD

Measurement of the energy spectrum of cosmic-ray induced neutrons aboard an ER-2 high-altitude airplaneP. Goldhagena,*, M. Reginattoa, T. Knissb, J.W. Wilsonc, R.C. Singleterryc,I.W. Jonesc, W. Van Stevenincka

US Department of Energy, Environmental Measurements Laboratory

X1

23628.1

Neutron Flux @ Palestine, Texas 31N, 95W

Calibrated Value from Table and Flux Calculator

() = 1 neutron /cm^2/s

Altitude (km) Internet Flux1.28

(184.57)0.0122 (80.33)

3.4 (96.61)

10 (114.53)

10.2 (161.29) MEAN

STANDARD DEVIATION

0 0.9 0.00488 0.01120 0.00932 0.00786 0.00558 0.00946 0.00168

1.524 3.17 0.01718 0.03946 0.03281 0.02768 0.01965 0.03332 0.00591

3.048 9.24 0.05006 0.11503 0.09564 0.08068 0.05729 0.09712 0.01722

4.572 22.92 0.12418 0.28532 0.23724 0.20012 0.14210 0.24090 0.04272

6.096 49.32 0.26722 0.61397 0.51051 0.43063 0.30578 0.51837 0.09192

7.62 93.55 0.50685 1.16457 0.96833 0.81682 0.58001 0.98324 0.17436

9.144 158.77 0.86022 1.97647 1.64341 1.38627 0.98438 1.66872 0.29591

10.668 244.25 1.32335 3.04058 2.52821 2.13263 1.51435 2.56714 0.45523

12.192 344.81 1.86818 4.29242 3.56909 3.01065 2.13783 3.62405 0.64265

13.716 452.03 2.44910 5.62716 4.67892 3.94683 2.80259 4.75097 0.84248

15.24 556.73 3.01636 6.93054 5.76265 4.86100 3.45173 5.85140 1.03762

16.764 651.46 3.52961 8.10980 6.74319 5.68812 4.03906 6.84704 1.21418

18.288 731.79 3.96484 9.10980 7.57468 6.38950 4.53711 7.69133 1.36389

19.812 796.42 4.31500 9.91435 8.24366 6.95381 4.93781 8.37061 1.48435

21.336 846.27 4.58509 10.53492 8.75965 7.38907 5.24688 8.89455 1.57726

22.86 883.44 4.78648 10.99763 9.14439 7.71361 5.47734 9.28521 1.64653

24.384 910.4 4.93255 11.33325 9.42346 7.94901 5.64449 9.56857 1.69678

25.908 929.47 5.03587 11.57065 9.62085 8.11552 5.76273 9.76900 1.73232

27.432 942.64 5.10722 11.73459 9.75717 8.23051 5.84438 9.90742 1.75687

28.956 951.48 5.15512 11.84464 9.84867 8.30769 5.8991910.0003

3 1.77335

29.7 954.6 5.17202 11.88348 9.88096 8.33493 5.9185310.0331

3 1.77916

Neutron Flux v Altitude

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Neu

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Series1

The role of cosmic rays in the atmospheric processesY I StozhkovLebedev Physical Institute, Russian Academy of Sciences, Moscow, Russia

Particle Flux vs Altitude

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Series1

3% Sam ple Count vs Peak Altitude

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Series1

3% Sam ple Count v Peak Altitude

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Series1

Neutrons Counted vs Peak Sample Altitude (10 mins) 15 cm^2 Scintillator @ 3% efficiency

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Series1

Weight Budget:

Sensor circuitry / PMTs and Bases111 g

Frame 90 g

Control circuitry (Balloon SAT) 70 g

Moderating Material/ Scintillator 88.4 / 30 g

Power Source 67.6 g

Support System/ Platforms 15 g

Insulation 15 g

TOTAL 487 g* (398.4)

*Weights listed are subject to change as specific sensors and components are found and completed.

1.0 Payload Design1.1 Frame

1.1.1 Balloon attachments1.2 Sensing Structure

1.2.1 PMT/Diode attachment 1.2.2 Scintillation base 1.2.3 Photon shielding

1.2.4 Photon capture 1.2.5 Photon noise reduction

2.0 Electrical Design2.1 Preamp

2.2 Discriminator 2.2.1 Comparator

2.3 Counter2.4 Basic Stamp2.5 Sensing

2.5.1 DC/DC Converter 2.5.2 Photodiode 2.5.3 PMT

2.5.3.1 Base 2.5.3.2 Structural platform

3.0 Software Design 3.1 Basic Stamp 3.1.1 Pre-flight initialization 3.1.2 Flight software 3.1.3 Post flight data retrieval 3.2 PC software 3.2.1 Calibration 3.2.2 Altitude-Time converter 3.2.3 Graphical representation4.0 Power 4.1 BalloonSat 4.2 PMT 4.2.1 DC/DC converter 4.3 Photodiodes 4.3.1 DC/DC converter 4.4 Preamp/Discriminator

START

READR1,R2

t=0

t=1min?

R=summation of R1R’=summation of

R2t=0

STORE(R,T1)(R’,T2)

T=flightduration?

END

YES

NO

YES

NO