3/2003 rev 1 i.2.9 – slide 1 of 35 session i.2.9 part i review of fundamentals module 2basic...
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3/2003 Rev 1 I.2.9 – slide 1 of 35
Session I.2.9
Part I Review of Fundamentals
Module 2 Basic Physics and MathematicsUsed in Radiation Protection
Session 9 Nuclear Reactions
IAEA Post Graduate Educational CourseRadiation Protection and Safety of Radiation Sources
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Various examples of nuclear reactions will be discussed
Students will learn about properties of neutrons, nuclear decay processes, cross section, neutron interactions, and various kinds of nuclear reactions including charged particle reactions, spallation, fission and fusion reactions
Introduction
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Content
Properties of neutrons Nuclear decay processes Cross section Neutron interactions Charged particle reactions Spallation Fission Fusion
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Overview
Various kinds of nuclear reactions will be discussed and examples shown
Health physics significance and energy considerations of nuclear reactions will be discussed
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Chadwick, 1932, alpha bombardment
He + Be C + n + Q
Neutron Discovery
Thermal (0.0025 eV)Slow (1 - 100 eV)Epithermal (100 eV – 100 keV)Fast (100 keV – 1 MeV)Ultrafast (>1 MeV)
Neutron Classification
Properties of Neutrons
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Neutron Characteristics symbol - n no charge rest energy 939.507 MeV has a magnetic moment it is a fermion
Neutron Interaction with matter Scattering (2 mechanisms) Absorption (>4 mechanisms)
Properties of Neutrons
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Nuclear ReactionsNuclear Decay
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Nuclear ReactionsAlpha Decay
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Nuclear ReactionsBeta Decay
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Nuclear ReactionsPositron Decay or Electron Capture
Electron Capture
Positron Emission
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Nuclear ReactionsSummary of Major Decay Mechanisms
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Cross Section
where
= cross section
R = number of reactions per unit time per nucleus
I = number of incident particles per unit time per unit area
= RI
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Nuclear ReactionsFast Neutron Interactions
Elastic scattering - neutrons interact with particles of approximately the same mass such as protons (billiard ball analogy)
Occurs in materials rich in hydrogen such as water, wax, concrete
Accounts for about 80% of fast neutron dose to tissue
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Inelastic scattering – neutrons interact with particles of much greater mass, for example, iron (table tennis ball vs bowling ball analogy)
Nuclear ReactionsFast Neutron Interactions
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Nuclear ReactionsElastic Scattering of Neutrons
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Nuclear ReactionsInelastic Scattering of Neutrons
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Neutron Reactions
(n, CP) QHeLiBn 42
73
105
10
CoCon 605910
(n, gamma)
LiMoUUn 1399523692
23592
10 *
(n, fission)
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Nuclear ReactionsNeutron Absorption, Charged Particle
n + 10B 7Li(*) +
7Li(*) 7Li + soft gamma (480 KeV)
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Fission
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Breeding 239Pu from 238U Neutron Capture
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Details of 239U Decay to 239Pu
239U (23.5 min) 239Np (2.3 d) 239Pu
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Nuclear ReactionsCharged Particle Bombardment
p + 68Zn 67Ga + 2n
+ 16O 18F + p + n
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Nuclear ReactionsSpallation
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Spallation Products
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Spallation Produced by Neutrons or Protons
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Nuclear Fusion ReactionsUtilize Isotopes of Hydrogen
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Nuclear ReactionsFusion
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Deuteron – Deuteron Fusion
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Tritium – ProtonProduction from Fusion
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3He with Neutron Production from Fusion
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Fusion - Tokamak
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Energy ProductionReactions in Stars
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CNO Energy ProductionReactions in Stars
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Summary
Various examples of nuclear reactions were discussed
Students learned about properties of neutrons, nuclear decay processes, cross section, neutron interactions, and various kinds of nuclear reactions including charged particle reactions, spallation, fission and fusion
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Where to Get More Information
Cember, H., Johnson, T. E., Introduction to Health Physics, 4th Edition, McGraw-Hill, New York (2008)
Martin, A., Harbison, S. A., Beach, K., Cole, P., An Introduction to Radiation Protection, 6th Edition, Hodder Arnold, London (2012)
Jelley, N. A., Fundamentals of Nuclear Physics, Cambridge University Press, Cambridge (1990)
Firestone, R.B., Baglin, C.M., Frank-Chu, S.Y., Eds., Table of Isotopes (8th Edition, 1999 update), Wiley, New York (1999)