| Preface | 8 |
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| Contents | 11 |
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| 1 Introduction to Nuclear Batteries and Radioisotopes | 15 |
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| Abstract | 15 |
| 1.1 Fundamental Concepts | 17 |
| 1.2 Nuclear Battery Design Considerations | 23 |
| 1.2.1 Surface Interface | 28 |
| 1.2.2 Volume Interface | 30 |
| 1.3 Products from Ionizing Radiation: Heat and Ion Pairs | 31 |
| 1.4 Geometrical Considerations in the Interface of an Isotropic Radiation Source to a Transducer | 42 |
| 1.5 Methodology for Analysis | 47 |
| 1.6 Summary | 48 |
| References | 49 |
| 2 Radioisotopes | 52 |
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| Abstract | 52 |
| 2.1 Existing Radioisotope Supplies | 52 |
| 2.1.1 Primordial Radioisotopes | 53 |
| 2.1.2 Cosmogenic Radioisotopes | 54 |
| 2.1.3 Manmade Radioisotopes | 58 |
| 2.2 Radioisotope Production | 62 |
| 2.2.1 Separation from Spent Fuel | 63 |
| 2.2.1.1 Bismuth Phosphate Process | 63 |
| 2.2.1.2 REDOX Process | 66 |
| 2.2.1.3 PUREX Process | 67 |
| 2.2.1.4 Other Processes | 68 |
| 2.2.2 Separation from Natural Decay Chains | 70 |
| 2.2.3 Production by Neutron Capture in a Reactor | 76 |
| 2.2.4 Production by Accelerator | 77 |
| 2.3 Cost of Radioisotopes | 80 |
| 2.3.1 Cost of Separation | 80 |
| 2.3.1.1 Cost Analysis | 81 |
| 2.3.1.2 Dissolution, Mixing and Drying Equipment | 81 |
| 2.3.1.3 Sunk Costs Considerations | 82 |
| 2.3.2 Cost of Neutron Capture | 82 |
| 2.3.3 Cost of Accelerator | 86 |
| 2.4 Other Factors Influencing Cost | 87 |
| 2.4.1 Safety | 87 |
| 2.4.2 Software | 87 |
| 2.4.3 Liquidity of Capital (Cash) | 88 |
| 2.5 Isotopes Produced from the Manhattan Project | 88 |
| 2.6 Mixed Oxide Fuel Fabrication Facility (MOX FFF) | 88 |
| 2.7 Summary | 89 |
| References | 90 |
| 3 Interactions of Ionizing Radiation with Matter and Direct Energy Conversion | 93 |
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| Abstract | 93 |
| 3.1 Ionizing Radiation Types and Ranges | 93 |
| 3.1.1 Fission Fragments | 93 |
| 3.1.2 Alpha Particles | 99 |
| 3.1.3 Beta Particles and Positrons | 102 |
| 3.1.4 Shielding Considerations | 104 |
| 3.1.5 Rules of Thumb and Their Limitations | 107 |
| 3.1.6 The Limitations of Average Beta Energy | 109 |
| 3.1.7 What Types of Radiation Work Best with Nuclear Batteries and Why | 114 |
| 3.2 Types of Transducers Used in Nuclear Batteries | 114 |
| 3.2.1 Ion Pair Based | 115 |
| 3.2.1.1 Efficiency of a Beta or Alpha Voltaic Cell Based on a Classic P-N Junction | 117 |
| Open Circuit Voltage (Voc) and the Driving Potential Efficiency | 120 |
| Depletion Zone Width and Current | 123 |
| 3.2.2 Schottky Barriers | 125 |
| 3.2.2.1 Liquid Semiconductor Schottky Barrier | 127 |
| 3.2.3 Direct Charge Collection | 128 |
| 3.2.3.1 The Ideal Match Between the Electric Field and the Ionizing Radiation | 128 |
| DCNB Design and Inefficiencies | 129 |
| Mismatch of the Electric Field with the Energy Distribution of the Particles | 132 |
| Effects of Angular Distribution | 133 |
| 3.2.3.2 Reciprocating Cantilever | 136 |
| 3.2.4 Indirect | 137 |
| 3.2.4.1 Gaseous Fluorescers | 138 |
| PIDEC and RECS | 138 |
| Spectral Considerations for Excimer Emitters | 139 |
| Effect of Impurities on Excimer Efficiency | 144 |
| PIDEC | 146 |
| Nuclear-Driven Fluorescers | 149 |
| The Ion Source | 150 |
| Excimer Fluorescers | 150 |
| The Photon Energy Converter | 152 |
| Photovoltaic Conversion of Narrowband Fluorescence | 152 |
| Wide Band-Gap Photovoltaic Materials | 156 |
| Gas | 159 |
| Solid Sources that Can Mimic Gas | 159 |
| Solid-State | 159 |
| 3.2.5 Solid-State Emitter and PV | 161 |
| 3.2.5.1 Phosphors | 162 |
| 3.2.6 Hybrid Solid-State Emitter | 167 |
| 3.2.7 Heat Based | 168 |
| 3.2.7.1 Seebeck Effect and RTG | 168 |
| 3.2.7.2 Thermoionics | 171 |
| 3.2.7.3 Thermophotovoltaics | 180 |
| 3.3 Summary | 183 |
| References | 184 |
| 4 Power Density Dilution Due to the Interface of the Isotope with the Transducer | 188 |
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| Abstract | 188 |
| 4.1 Introduction | 189 |
| 4.2 Phase of the Radioisotope | 191 |
| 4.2.1 Radioisotope in Solid Phase | 191 |
| 4.2.2 Radioisotope in Liquid Phase | 193 |
| 4.2.3 Radioisotope in Gaseous Phase | 194 |
| 4.2.4 Gaseous-like Radioisotopes | 198 |
| 4.3 Phase of the Transducer | 200 |
| 4.3.1 Solid Phase Transducer | 200 |
| 4.3.2 Liquid Phase Transducer | 200 |
| 4.3.3 Gas Phase Transducer | 203 |
| 4.3.4 Plasma Phase Transducer | 203 |
| 4.4 Surface Interface | 203 |
| 4.4.1 Methods of Forming Surface Sources | 204 |
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