Introduction to Radiological Physics Radiation Dosimetry

INTRODUCTION TO RADIOLOGICAL PHYSICS AND RADIATION DOSIMETRY......Page 2
Contents......Page 14
I. Introduction......Page 26
II. Types and Sources of Ionizing Radiations......Page 27
A. Consequences of the Random Nature of Radiation......Page 30
B. Simple Description of Radiation Fields by Nonstochastic Quantities......Page 33
C. Differential Distributions vs. Energy and Angle of Incidence......Page 35
E. Planar Fluence......Page 40
I. Introduction......Page 45
A. Definition......Page 46
B. Relation of Kerma to Energy Fluence for Photons......Page 47
C. Relation of Kerma to Fluence for Neutrons......Page 48
D. Components of Kerma......Page 49
A. Definition......Page 51
IV. Comparative Examples of Energy Imparted, Energy Transferred and Net Energy Transferred......Page 52
A. Definition......Page 54
B. Definition of W......Page 55
C. Relation of Exposure to Energy Fluence......Page 56
E. Significance of Exposure......Page 57
B. Dose Equivalent, H......Page 59
C. Specification of Ambient Radiation Levels......Page 61
II. Simple Exponential Attenuation......Page 63
III. Exponential Attenuation for Plural Modes of Absorption......Page 65
IV. "Narrow-Beam" Attenuation of Uncharged Radiation......Page 67
V. Broad-Beam Attenuation of Uncharged Radiation......Page 69
VI. Some Broad-Beam Geometries......Page 71
VII. Spectral Effects......Page 75
VIII. The Buildup Factor......Page 78
IX. The Reciprocity Theorem......Page 80
II. Radiation Equilibrium......Page 86
A. CPE for Distributed Radioactive Sources......Page 90
B. CPE for Indirectly Ionizing Radiation from External Sources......Page 92
IV. CPE in the Measurement of Exposure......Page 95
V. Relating Absorbed Dose to Exposure for x- and γ-Rays......Page 96
B. Proximity to a Boundary of lnhomogeneity in the Medium......Page 97
C. High-Energy Radiation......Page 99
VII. Transient Charged-Particle Equilibrium (TCPE)......Page 100
I. Introduction......Page 105
A. Alpha Disintegration......Page 111
B. Beta Disintegration......Page 113
C. Electron-Capture (EC) Transitions......Page 118
D. Internal Conversion vs. γ-Ray Emission......Page 121
E. Tables for Dose Estimation in Appendix C......Page 124
I. Total Decay Constants......Page 126
III. Units of Activity......Page 127
IV. Mean Life and Half-Life......Page 128
V. Radioactive Parent-Daughter Relationships......Page 130
VI. Equilibria in Parent-Daughter Activities......Page 132
B. Daughter Shorter-Lived than Parent, λ2 > λ1......Page 133
C. Only Daughter Much Shorter-Lived than Parent, λ2 >>λ1......Page 137
VII. Removal of Daughter Products......Page 139
VIII. Radioactivation by Nuclear Interactions......Page 140
IX. Exposure-Rate Constant......Page 142
I. Introduction......Page 149
II. Compton Effect......Page 150
A. Kinematics......Page 151
B. Interaction Cross Section for the Compton Effect......Page 154
C. Energy-Transfer Cross Section for the Compton Effect......Page 159
A. Kinematics......Page 163
B. Interaction Cross Section for the Photoelectric Effect......Page 164
C. Energy-Transfer Cross Section for the Photoelectric Effect......Page 167
IV. Pair Production......Page 171
A. Pair Production in the Nuclear Coulomb- Force Field......Page 173
B. Pair Production in the Electron Field......Page 175
C. Pair Production Energy-Transfer Coefficient......Page 177
V. Rayleigh (Coherent) Scattering......Page 178
A. Mass Attenuation Coefficient......Page 179
C. Mass Energy-Absorption Coefficient......Page 180
D. Coefficients for Compounds and Mixtures......Page 181
E. Tables of Photon Interaction Coefficients......Page 182
I. Introduction......Page 185
A. “Soft” Collisions (b >> a)......Page 186
B. Hard (or “Knock-On”) Collisions (b ~ a)......Page 187
C. Coulomb-Force Interactions with the External Nuclear Field (b << a)......Page 188
D. Nuclear Interactions by Heavy Charged Particles......Page 189
III. Stopping Power......Page 190
A. The Soft-Collision Term......Page 191
B. The Hard-Collision Term for Heavy Particles......Page 192
D. Mass Collision Stopping Power for Electrons and Positrons......Page 196
E. Polarization or Density-Effect Correction......Page 197
F. Mass Radiative Stopping Power......Page 200
G. Radiation Yield......Page 202
H. Stopping Power in Compounds......Page 203
I. Restricted Stopping Power......Page 204
A. CSDA Range......Page 205
B. Projected Range......Page 208
D. Electron Range......Page 209
E. Photon “Projected Range”......Page 211
A. Dose in Thin Foils......Page 212
B. Mean Dose in Thicker Foils......Page 215
C. Mean Dose in Foils Thicker than the Maximum Projected Range of the Particles......Page 217
D. Electron Backscattering......Page 218
E. Dose vs. Depth for Charged-Particle Beams......Page 220
A. Fluorescence X-Rays......Page 228
B. Bremsstrahlung X-Rays......Page 235
III. X-Ray Filtration and Beam Quality......Page 244
A. X-Ray Filtration......Page 245
B. X-Ray Beam-Quality Specification......Page 246
I. Bragg-Gray Theory......Page 256
B. Second Bragg-Gray Corollary......Page 260
III. Spencer’s Derivation of the Bragg-Gray Theory......Page 262
IV. Averaging of Stopping Powers......Page 264
V. Spencer Cavity Theory......Page 267
VI. Burlin Cavity Theory......Page 273
VII. The Fano Theorem......Page 280
VIII. Other Cavity Theories......Page 282
IX. Dose Near Interfaces between Dissimilar Media under γ-irradiation......Page 284
B. What Is a Dosimeter?......Page 289
C. Simple Dosimeter Model in Terms of Cavity Theory......Page 290
A. For Photons and Neutrons......Page 291
B. For Charged Particles......Page 299
B. Precision and Accuracy......Page 302
C. Dose Range......Page 304
D. Dose-Rate Range......Page 306
E. Stability......Page 307
F. Energy Dependence......Page 308
G. Miscellany......Page 315
A. Conventional Designs......Page 317
B. Novel Free-Air-Chamber Designs......Page 325
A. Thimble-Type Chambers......Page 329
B. Flat Cavity Chambers; Extrapolation Chambers......Page 336
A. General Considerations......Page 340
B. Charge Measurement......Page 344
C. Current Measurement......Page 348
D. Atmospheric Corrections......Page 351
A. Charge Produced vs. Charge Collected......Page 355
C. Types of Gases......Page 357
D. Electric Field Strength vs. Chamber Geometry......Page 358
E. Boag’s Treatment of Mie’s Theory of General or Volume Recombination for Constant Dose Rate in an Electronegative Gas such as Air......Page 359
F. Extrapolation for Initial Recombination......Page 361
G. Pulsed Radiation......Page 362
A. Definition of Wand w......Page 364
B. Calculation of W......Page 365
C. Experimental Measurement of W or W......Page 366
D. Energy Dependence of W......Page 367
G. “W” in Semiconductors......Page 368
II. Absolute Cavity Ion Chambers......Page 371
A. Exposure Calibration of Ion Chambers......Page 372
B. Ngas Calibration of Ion Chambers......Page 375
C. Calibration of Ion Chambers in Terms of Absorbed Dose in Water......Page 381
A. Calibrations in Free Space......Page 382
B. Calibration of Photon Beams in Phantoms by Means of an Exposure-Calirated Ion Chamber......Page 391
C. Substitution of Plastics for Water in Photon-Beam Phantoms......Page 397
A. Chamber Wall Material Same as Phantom......Page 401
B. Chamber Wall Material Different from Phantom......Page 403
B. Electron-Beam Perturbation Corrections for Cavity Chambers in Phantoms......Page 405
C. The CE Method......Page 410
D. The Ngas Method......Page 413
A. The Thermoluminescence Process......Page 420
B. TLD Readers......Page 425
D. TLD Forms......Page 428
E. Calibration of Thermoluminescent Dosimeters......Page 430
F. Advantages and Disadvantages......Page 435
A. Photographic Process......Page 436
B. Optical Density of Film......Page 437
D. X-Ray Energy Dependence......Page 439
E. Nuclear Track Emulsions......Page 440
F. Advantages and Disadvantages of Photographic Dosimetry......Page 441
B. Basic Principles......Page 443
C. General Procedures......Page 444
D. The Fricke Ferrous Sulfate Dosimeter......Page 446
E. Other Chemical Dosimeters......Page 448
F. General Advantages and Disadvantages of Aqueous Chemical Dosimetry Systems......Page 449
G. References......Page 450
A. Temperature Measurement......Page 451
B. Calorimeter Design......Page 452
D. Conclusions......Page 460
A. Gas Multiplication......Page 463
B. Proportional Counters......Page 466
C. Geiger-Müller Counters......Page 471
A. Introduction......Page 475
B. Light Output Efficiency......Page 476
D. Light Collection and Measurement......Page 477
E. Comparison with an Ionization Chamber......Page 480
F. Pulse-Shape Discrimination......Page 481
B. Basic Operation of Reverse-Biased Semiconductor Junction Detectors......Page 482
D. Lithium-Drifted Si and Ge Detectors......Page 484
G. Fast-Neutron Dosimetry......Page 486
I. Introduction......Page 488
A. Thermal Neutrons......Page 489
A. Tissue Composition......Page 490
B. Kerma Calculations......Page 491
C. Thermal-Neutron Interactions in Tissue......Page 492
IV. Neutron Sources......Page 493
VI. Calculation of the Absorbed Dose in a Cylindrical Phantom Representing the Human Body......Page 497
A. Occurrence of n + γ Mixed Fields......Page 500
B. Equation for n + γ Dosimeter Response......Page 501
C. Separate Measurement of Neutron and γ-Ray Dose Components by Paired Dosimeters......Page 502
D. Relative n vs. γ Sensitivity of Dosimeters......Page 504
E. Calibration of a Tissue-Equivalent Ion Chamber for n + γ Dosimetry......Page 520
F. Calibration of the Low-Neutron-Sensitivity Dosimeter for Use in the Paired-Dosimeter Method......Page 523
A. Track-Descriptive Approach: Linear Energy Transfer......Page 526
C. Stochastic Quantities......Page 528
REFERENCES......Page 531
A. 1 Physical Constants......Page 550
A.2 Conversion Factors......Page 551
B.1 Data Table of the Elements......Page 552
B.2 Data Table for Compounds and Mixtures......Page 556
B.3 Compositions of Mixtures......Page 557
C Radionuclide Output Data......Page 558
D. 1 Klein-Nishina Interaction Cross Sections for Free Electrons......Page 562
D.2 Photon Interaction Cross Sections......Page 563
D.3 Mass Attenuation Coefficients, Mass Energy-Transfer Coefficients, and Mass Energy-Absorption Coefficients for Photon Interactions in Various Media......Page 581
D.4 Mass Energy-Absorption Coefficients for Various Media......Page 587
E Electron Mass Stopping Powers, Ranges, Radiation Yields, and Density Corrections......Page 588
F Neutron Kerma Factors F......Page 612
INDEX......Page 624