1. Angular Distribution of
Cosmic Ray Muons
Investigators: Peter Karn
David Kearsley
Project Advisor: Phillip Dudero
http://mxp.physics.umn.edu/s07/Projects/S07_CosmicRaysDistribution/

2. Project Relevance & Applications
• Investigation of high-energy astrophysical processes.
• CR Damage to quantum-scale computer components (e.g.
Josephson Junctions) and related devices.
• CR Effects on CCDs (Charge-Coupled Devices) used in
astrophysics.
• CR Effects on telecommunications & spaceflight systems.

3. Sources of Cosmic Rays
• Short Timescale Solar Activity
– Flares
• Stellar Processes
– Supernova Nucleosynthesis
– Neutron star core collapse
• Gamma Ray Bursts (GRB)
• Galactic Processes
– Active Galactic Nuclei (AGN) jets
Compton Gamma Ray
Observatory (GRO)

4. Cosmic Ray Shower Processes I
AIRES Cosmic Ray Shower Simulation of 1TeV incident
proton (x = y = 5km, z = 20km), University of Chicago.
Cosmic Ray Shower Products
(CERN).
x
y
z

5. Cosmic Ray Shower Processes II
• Incident Particles
– Types: p, n, He, heavy nuclei
– Energies: ~GeV → ~100TeV
• Secondary Products
– Types: p, π+
, π−
, π0
, γ
– Energies: ~GeV
• End Products
– Types: µ+
, µ−
, e−
, e+
, ±
νe, ±
νµ
– Energies: ~MeV → ~GeV
Muons (τ0 = 2.2 × 10-6
sec) are
observed to survive at sea-level
due to Lorentz time dilation: )/(1 22
0
0
cv−
==
τ
γττ

6. Angular Distribution
• 1st Order Approximation:
1. F(0) = F(⊥)
2. F(±π/2) = F(tangential)
• F(θ) = F(0)cos2
(θ)
1. F = particle flux in (N)(sec-1
)(sr-1
).
2. N = Number of events.
3. θ = Incident angle relative to zenith (= 0).
4. Angular area is measured in steradians (sr),
such that, (β×φ) = (1rad)×(1rad).

7. KAKE Cosmic Ray Telescope I
• (D0) Coincidence
Detector a.k.a.
“PESTILENCE”
• (DM0) Zenith
Measurement
Detector a.k.a.
“FAMINE”
• (DM1) Angular
Distribution
Measurement
Detector a.k.a.
“WAR”
Plastic ScintillatorLight-PipePMT

8. KAKE Cosmic Ray Telescope II
• 3x Detectors
• 3x 2kV Power
Supplies
• 3x Discriminator
Channels:
– 10ns pulses
• 2x2 Coincidence:
– (DM0+D0)
– (DM1+D0)
• Dual-Counter
• NIM-TTL
Translator
• PCI 6602 DAQC
D0 DSC1
PS4
DM2
DM1
DM0
PS3
PS1
PS2
DSC2
DSC4
DSC3
COUNTER
PMT1
PMT2
PMT3
PMT4
LabWindowsCVI/Excel
NIM-TTL
COINCIDENCE

9. Detectors in Lab & Deployed
1. D0 with 5mm aluminum electron-shield.
2. DM0 on detector mounting fixture.
3. DM1 on extended mounting fixture.
4. (2x2)+(3x3) coincidence testing.
5. Fully configured telescope deployed on Tate roof.
21
3 4
5

10. Technical Issues
• Temperature Stability
– PMT Efficiency.
– Power Supply & PC overheating.
• Precipitation
– HV Cable & PMT protection.
• Calibration
– PMT Efficiency “Plateau” 2kV Power Supplies in Cooling Tent
L2R: DISC, COINC, NIM-TTL, 2xCounter
Detector/PMT Response Curve (PESTILENCE), [Source = Cobalt-60]
10.000
100.000
1000.000
10000.000
100000.000
1200 1300 1400 1500 1600 1700 1800
-VDC(PMT)
counts/sec

11. Experimental Data I
• Random Coincidence
Calculation
– dt = 10-8
sec
∆T = 8.64×104
sec
• NRandom(max) = 8.61×10-5
Events/Bin (theta=75.1deg)
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900
bin(t=100sec)
events
events(0)
events(75.1deg)
dt
T
N
N
NN
dt
T
NN
N
Total
Random
Total
Random






∆
=
=






∆
=
2
21
21
Events/Bin (theta=44.6deg)
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900
bin(t=100sec)
events
events(0)
events(44.6deg)
Events/Bin (theta=15.1deg)
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900
bin(t=100sec)
events
events(0)
events(15.1deg)
Raw Counts for:
θ(WEST) = (15º, 45º, 75º)

12. Experimental Data II
Plots of F(θ)/F(0) vs θ & cos2
(θ): 24 Hours
Muon Flux Ratio F(θ)/F(0) [24Hours]
0.0666
0.2477
0.5065
0.7470
0.9320
1.0000
0.9320
0.7470
0.5065
0.2477
0.0666
0.083
0.179
0.425
0.705
0.905
1.000
0.829
0.667
0.417
0.198
0.087
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
1.100
-90.0 -75.0 -60.0 -45.0 -30.0 -15.0 0.0 15.0 30.0 45.0 60.0 75.0 90.0
theta(deg)
F(theta)/F(0)
cos^2(theta)
F(theta)/F(0)
Poly. (cos^2(theta))

13. Muon Flux Ratio F(theta)/F(0), [DAY]
0.0666
0.2477
0.5065
0.7470
0.9320
1.0000
0.9320
0.7470
0.5065
0.2477
0.0666
0.087
0.185
0.443
0.724
0.977
1.000
0.856
0.768
0.423
0.199
0.088
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
1.100
-90.0 -75.0 -60.0 -45.0 -30.0 -15.0 0.0 15.0 30.0 45.0 60.0 75.0 90.0
theta(deg)
F(theta)/F(0)
cos^2(theta)
F(theta)/F(0)
Poly. (cos^2(theta))
Plots of F(θ)/F(0) vs θ & cos2
(θ): DAY
Experimental Data III

14. Muon Flux Ratio F(theta)/F(0), [NIGHT]
0.0666
0.2477
0.5065
0.7470
0.9320
1.0000
0.9320
0.7470
0.5065
0.2477
0.06660.080
0.173
0.407
0.642
0.857
1.000
0.814
0.635
0.408
0.196
0.086
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
1.100
-90.0 -75.0 -60.0 -45.0 -30.0 -15.0 0.0 15.0 30.0 45.0 60.0 75.0 90.0
theta(deg)
F(theta)/F(0)
cos^2(theta)
F(theta)/F(0)
Poly. (cos^2(theta))
Experimental Data IV
Plots of F(θ)/F(0) vs θ & cos2
(θ): NIGHT

15. Acknowledgements & References
Dr. Jeremiah Mans, Dr. Michael DuVernois, Kurt Wick, Paul Hinrichs, Dave Lee
References
• Cosmic Rays, T.K.Gaisser, T.Stanev, (Bartol Research Inst, Univ. of Delaware), 2002, Rev. P.V.
Sokolsky (Univ. of Utah), R.E.Streitmatter, 2005.
• Anisotropy of Primary Cosmic Ray Flux in Super-Kamiokande, Y.Oyama (KEK), 2006, IPNS Seminar
(KEK).
• Background Cosmic Ray Flux Measured by Balloon Flight Engineering Model, T.Kamae, GLAST-LAT
Collaboration Meeting at NASA-Goddard, 2002.
• Terrestrial Cosmic Ray Intensities, J.F.Ziegler, IBM Journal of Research and Development, Vol. 42,
#1, 1998.
• Measuring the Lateral Width of Cosmic Ray Particle Showers, G.Beebe, R.Peters, Department of
Physics and Astrophysics, University of Minnesota, May 2006.
• High Energy Astrophysics, Volume #1: Particles, Photons and their Detection, M.Longair, Cambridge
University Press, New York, 1981, 1992.
• Introduction to Elementary Particles, D.J.Griffiths, John Wiley & Sons Inc., 1987.
• Quantum Physics of Atoms, Molecules, Solids, Nuclei and Particles, 2nd Ed., R.Eisberg, R.Resnick,
John Wiley & Sons, Inc., New York, 1974, 1985.
• Review of Particle Physics: Particle Physics Booklet, Physical Review D-66, K.Hagiwara et al, 2002.
• S.J.Sciutto, AIRES Project, Department of Physics, Universidad Nacional de La Plata, Argentina.