Neutron Imaging and Applications (eBook)

Neutron Imaging and Applications 2
Preface 6
Contents 13
Contributors 15
Section A 17
Introduction to the Neutron 18
1.1 Introduction 18
1.2 Interactions with Matter and Cross Sections 20
References 26
Neutron Sources and Facilities 28
2.1 Introduction 28
2.2 Neutron Production 30
2.2.1 Reactors 30
2.2.2 Proton Accelerator-Based Sources 30
2.3 Moderation Mechanisms for Reactors and Spallation Sources 36
2.3.1 Reactor Neutron Sources 36
2.3.2 Pulsed Spallation Neutron Sources 37
2.4 Comparison of Source Types 41
2.5 Neutron Facilities 42
2.6 Smaller Neutron Sources for Imaging and Other Applications 42
References 44
Neutron Optics 46
3.1 Introduction 46
3.2 Source Optics 47
3.3 Reflection Optics: Neutron Guides 48
3.4 Diffraction Optics 51
3.5 Refraction Optics 55
3.6 Polarisation Optics 55
References 60
Neutron Detectors for Imaging 61
4.1 Overview of Neutron Converters 61
4.2 Data Acquisition for Continuous and Time-Dependent Applications 63
4.3 Photographic Film Detectors 63
4.4 Scintillator and Storage Phosphor Detectors 65
4.5 Gas Detectors 70
4.6 Solid-State Detectors 72
4.7 Conclusion 74
References 74
Section B 78
Neutron Radiography 79
5.1 Introduction 79
5.2 A History of Neutron Radiography 80
5.3 Basic Principles 81
5.3.1 Sources 81
5.3.2 Moderation 82
5.3.3 Collimation 82
5.3.4 Detectors 83
5.4 Image Analysis 84
5.5 Direct Radiographic Method 85
5.6 Indirect Radiographic Method 87
5.7 Track-Etch Method 87
5.8 Electronic Imaging Methods 88
5.9 Nonfilm Imaging Methods 89
5.10 Standards 90
5.11 Conclusions 90
References 91
Neutron Tomography 93
6.1 Introduction 94
6.2 Geometric Considerations and Spatial Resolution 95
6.3 Mathematical Foundations of (Neutron) Tomography 98
6.3.1 Scanning 98
6.3.2 Image Reconstruction 102
6.4 Experimental Techniques and Results 106
6.4.1 Energy-Dispersive and Bragg-Edge Radiography and Tomography 106
6.4.2 Real-Time Radiography 109
6.4.3 Phase Contrast, Refraction, and Small-Angle Tomography 109
6.4.4 Refraction and Small-Angle Scattering Tomography 112
6.5 Outlook 118
References 118
Mathematics of Neutron Imaging 121
7.1 Introduction 121
7.2 Neutron Image Formation and Resolution Analysis 124
7.2.1 Resolution Modeling 124
7.2.2 System Performance Measurement 126
7.3 Volumetric Imaging 129
7.3.1 Filtered Backprojection 130
7.3.2 Iterative Reconstruction 133
7.3.3 Computer Platforms 136
7.4 Conclusions and Application 136
References 138
Neutron Phase Imaging 140
8.1 Introduction 140
8.2 Principles 141
8.2.1 Phase Shift Versus Attenuation 141
8.2.2 Phase Tomography 143
8.2.2.1 Reconstruction from Phase Shift Projections 144
8.2.2.2 Reconstruction from Phase Gradient Projections 145
8.2.2.3 Reconstruction from Laplacian Phase Projections 146
8.3 Experimental Methods 147
8.3.1 Crystal Interferometer 147
8.3.2 Refraction-Based Techniques 150
8.3.2.1 Crystal Analyzer-Based Techniques 150
8.3.2.2 Grating Interferometers 151
8.3.3 Propagation-Based Techniques 156
8.4 Coherence Requirements 158
References 161
Thermal Neutron Holography 163
9.1 Introduction 163
9.2 Atomic-Resolution Holography 165
9.3 Neutrons 166
9.4 Neutron Holography and K Lines 167
9.5 Theory 168
9.6 Reconstruction of the Diffraction Patterns from S Wave Scatterers 170
9.7 Inside Source Neutron Holography 171
9.8 Inside Detector Neutron Holography 174
9.9 Holographic Reconstruction from Multiple Incoherent Scatterers 176
9.10 Holography and Poorly Crystallized Proteins 176
9.11 The Future 178
9.12 Concluding Remarks 178
References 178
Novel Imaging Techniques: Polarized Neutrons and Neutron-Based Magnetic Resonance Imaging 181
10.1 Neutron Spin Polarized Imaging of Magnetic Field 181
10.2 Spin Echo Imaging 185
10.3 Prospects for Neutron-Probed Magnetic Resonance Imaging 191
References 196
Section C 198
Neutron Imaging for the Hydrogen Economy 199
11.1 Introduction 199
11.2 Neutron Imaging of Fuel Cells and Hydrogen Storage Devices 200
11.2.1 Neutron Imaging of Fuel Cells 200
11.2.2 Neutron Imaging of Hydrogen Storage Devices 202
11.2.3 Primary Areas of Applications 204
11.2.3.1 Efficient Flow Field Design 204
11.2.3.2 Water Dynamics Through the PEM 204
11.2.3.3 GDL Characteristics and Water Retention 205
11.2.3.4 Characterization of Two-Phase Flow Phenomena in the Flow Field 206
11.2.3.5 Membrane Durability 206
11.2.3.6 Materials for Hydrogen Storage 207
11.3 Neutron Imaging Facilities and Techniques 207
11.3.1 Basic Principles 207
11.3.2 Imaging Techniques 208
11.3.2.1 Phase Imaging and Other Emerging Techniques 209
11.4 Neutron Imaging Facilities for Fuel Cell Research 210
11.5 Examples of PEM Fuel Cell Neutron Imaging 211
11.6 Conclusion 213
References 214
Material Science and Engineering with Neutron Imaging 216
12.1 Introduction 216
12.2 Phase Change and Transport During Metal Casting 218
12.3 Particulate Materials and Porous Media 222
12.4 Stroboscopic and Dynamic Neutron Imaging 225
12.5 Residual Stress Imaging 228
12.6 Bragg Edge-Based Energy Selective Neutron Imaging 230
References 233
Novel Neutron Imaging Techniques for Cultural Heritage Objects 235
13.1 Imaging, Neutrons, and Cultural Heritage 236
13.2 Two Neutron Beam Analytical Techniques: Neutron Resonance Capture Analysis and Prompt Gamma-Ray Activation Analysis 241
13.2.1 Neutron Resonance Capture Analysis 241
13.2.2 Prompt Gamma-Ray Activation Analysis 242
13.3 Combined Prompt Gamma-Ray Activation Analysis Scanning and Neutron Tomography 246
13.4 Imaging with Neutron Resonances 249
13.5 Applications to Cultural Heritage Studies 250
References 256
Probing the Potential of Neutron Imaging for Biomedical and Biological Applications 259
14.1 Introduction 259
14.2 First Experimental Measurements on Biological Tissues 260
14.3 Neutron Dosimetry: A Short Overview 264
14.4 Recent Trends 264
14.5 Small Particulate Gadolinium Oxide (SPGO) Nanoparticles for Targeted and Nontargeted Contrast Enhancement for Future Biomedical Neutron Imaging Applications 268
14.6 Summary 269
References 269
Neutron Stimulated Emission Computed Tomography: A New Technique for Spectroscopic Medical Imaging 271
15.1 Introduction and Background 271
15.1.1 Principle 273
15.1.2 Applications in Medical Imaging 274
15.1.2.1 Cancer Diagnosis 274
15.1.2.2 Noninvasive Measurement of Liver Iron and Copper 275
15.1.2.3 Small Animal Imaging 275
15.2 Imaging Facility and Apparatus 276
15.2.1 Neutron Source 277
15.2.2 Gamma Detector 278
15.2.3 Tomographic Acquisition Gantry 279
15.3 Current Applications 280
15.3.1 Experiment 1: Tomographic Acquisition of Multielement Phantom 280
15.3.2 Experiment 2: Diagnosis of Iron Overload in Human Liver Phantom 281
15.3.3 Experiment 3: Detection of Breast Cancer 284
15.4 Dose Analysis 286
15.5 Summary 287
15.6 Future 288
References 288
Visualizing Structures of Biological Macromolecules Through Indirect Imaging with Small-Angle Neutron Scattering and Modeling 295
16.1 Introduction 295
16.1.1 Theory 296
16.1.2 Contrast Variation 297
16.1.3 Information Content and Basic Data Analysis 298
16.2 Modeling for Visualization 299
16.2.1 Shape Restoration 300
16.2.2 Modeling with High-Resolution Structures 301
16.3 Examples 302
16.4 Conclusions 304
References 305
Neutron Imaging Applied to Plant Physiology 311
17.1 Introduction 311
17.2 Nondestructive Water Observation in Plants and Soils Using Neutron Transmission Imaging Techniques 312
17.2.1 Plant Roots Imbedded in Soil 313
17.2.2 Observation of Root Development Under Different Soil Conditions 314
17.2.3 Neutron Tomography of Root Systems 316
17.2.4 The Aboveground Portion of the Plant 317
17.3 Investigation of Wood Samples 319
17.4 Other Agricultural Applications 321
17.5 Concluding Remarks 322
References 322
Homeland Security and Contraband Detection 324
18.1 Introduction 324
18.1.1 Nature of Problem 324
18.1.2 Operational Issues 325
18.1.3 Practicality 327
18.1.4 Special Nuclear Materials 327
18.1.5 Explosives 328
18.1.6 Others 329
18.1.7 Physics of Detection 329
18.2 Representative Technical Approaches 329
18.2.1 Pulsed Fast Neutron Analysis 330
18.2.2 The ‘‘Nuclear Car Wash’’ 332
18.2.3 Combined Neutron and Gamma Radiography 332
18.2.4 Neutron Resonance Radiography 334
18.2.5 Apparatus 336
18.2.6 Elemental Maps 339
18.3 Summary and Future Outlook 342
References 342
Index 344