Fundamentals of Radiation Dosimetry and Radiological Physics

This book arises out of a course I am teaching for a three-credit (42 hour) graduate-level course Dosimetry Fundamentals being taught at the Department of Nuclear Engineering and Radiological Sciences at the University of Michigan. It is far from complete.
1 Photon Monte Carlo Simulation 1
1.1 Basic photon interaction processes 1
1.1.1 Pair production in the nuclear field 2
1.1.2 The Compton interaction (incoherent scattering) 5
1.1.3 Photoelectric interaction 6
1.1.4 R ayleigh (coherent) interaction 9
1.1.5 R elative importance of various processes 10
1.2 Photon transport logic 10
2 Electron Monte Carlo Simulation 21
2.1 Catastrophic interactions 22
2.1.1 Hard bremsstrahlung production 22
2.1.2 Møller (Bhabha) scattering 22
2.1.3 Positron annihilation 23
2.2 Statistically grouped interactions 23
2.2.1 "Continuous" energy loss 23
2.2.2 Multiple scattering 24
2.3 Electron transport "mechanics" 25
2.3.1 Typical electron tracks 25
2.3.2 Typical multiple scattering substeps 25
2.4 Examples of electron transport 26
2.4.1 Effect of physical modeling on a 20 MeV e− depth-dose curve 26
2.5 Electron transport logic 38
3 Transport in media, interaction models 45
3.1 Interaction probability in an infinite medium 45
3.1.1 Uniform, infinite, homogeneous media 46
3.2 Finitemedia 47
3.3 R egions of different scattering characteristics 47
3.4 Obtaining μ frommicroscopic cross sections 50
3.5 Compounds and mixtures 53
3.6 Branching ratios 54
3.7 Other pathlength schemes 54
3.8 Model interactions 55
3.8.1 Isotropic scattering 55
3.8.2 Semi-isotropic or P1 scattering 55
3.8.3 Rutherfordian scattering 56
3.8.4 Rutherfordian scattering—small angle form 56
4 Macroscopic Radiation Physics 59
4.1 Fluence 59
4.2 Radiation equilibrium 62
4.2.1 Planar fluence 63
4.3 Fluence-related radiometric quantities 65
4.3.1 Energy fluence 65
4.4 Attenuation, radiological pathlength 66
4.4.1 Solid angle subtended by a surface 67
4.4.2 Primary fluence determinations 68
4.4.3 Volumetric symmetry 68
4.5 Fano's theorem 69
5 Photon dose calculation models 77
5.1 Kerma, collision kerma, and dose for photo irradiation 77
5.1.1 Kerma 77
5.1.2 Collision Kerma 80
5.1.3 Dose 83
5.1.4 Comparison of dose depositionmodels 85
5.1.5 Transient charged particle equilibrium 87
5.1.6 Dose due to scattered photons 89
6 Electron dose calculation models 93
6.1 Themicroscopic picture of dose deposition 93
6.2 Stopping power 94
6.2.1 Totalmass stopping power 94
6.2.2 R estricted mass stopping power 98
6.3 Electron angular scattering 99
6.4 Dose due to electrons fromprimary photon interaction 100
6.4.1 A practical semi-analytic dose depositionmodel 101
6.5 The convolution method 105
6.6 Monte Carlo methods 105
7 Ionization chamber-based air kerma standards 111
7.1 Bragg-Gray cavity theory 111
7.1.1 Exposure measurements 112
7.2 Spencer-Attix cavity theory 114
7.3 Modern cavity theory 115
7.4 Interface effects 117
7.5 Saturation corrections 117
7.6 Burlin cavity theory 118
7.7 The dosimetry chain 118