Nuclear Chemistry

Description

This book is designed to serve as a textbook for core courses offered to postgraduate students enrolled in chemistry. This book can also be used as a core or supplementary text for nuclear chemistry courses offered to students of chemical engineering. The book covers various topics of nuclear chemistry like Shell model, fission/fusion reaction, natural radioactive equilibrium series, nuclear reactions carried by various types of accelerators. In addition, it describes the law of decay of radioactivity, type of decay, and interaction of radiation with matter. It explains the difference between ionization counter, scintillation counter and solid state detector. This book also consists of end-of-book problems to help readers aid self-learning. The detailed coverage and pedagogical tools make this an ideal textbook for postgraduate students and researchers enrolled in various chemistry and engineering courses. This book will also be beneficial for industry professionals in the allied fields. Foreword Preface Contents About the Authors 1 Nuclear Chemistry 1.1 Introduction 1.2 Atom 1.3 Nuclear Structure 1.4 Shell Model 1.5 Binding Energy of Nucleus 1.6 Fission Reaction 1.6.1 Thorium Fission 1.6.2 Fusion Reaction 1.7 Stability of Nucleon 2 Radioactivity 2.1 Introduction 2.2 Emission of Nuclear Particles 2.3 Interconversion of Nucleons Within the Nucleus 2.3.1 Conversion of Neutrons into Protons 2.3.2 Conversion of Proton to Neutron 2.4 Transition Between Nuclear Energy Levels … 2.5 Natural Radioactive Series 2.6 Decay Scheme 2.6.1 Rate of Decay 2.6.2 Half-Life 2.6.3 Radioactive Equilibrium 3 Nuclear Reaction 3.1 Introduction 3.2 Reactions Initiated by Charged Particles 3.3 Reactions Initiated by Uncharged Particles 3.3.1 Thermal Neutron Reaction 3.3.2 Fast Neutron Reaction 3.3.3 Nuclear Fission Reaction 3.4 Particle Accelerators 3.5 Conservation of Mass and Energy 3.6 Reaction Cross-Section 3.7 Some Features of Nuclear Reactions 3.7.1 The Purity of the Target Material 3.7.2 Conservation of Mass Relationship 3.7.3 Nature of the Products 3.8 Applications of Nuclear Reactions 4 Interaction of Radiation with Matter 4.1 Introduction 4.2 Types of Interactions 4.2.1 Ionization 4.2.2 Excitation 4.3 Interactions with Particulate Radiation 4.3.1 α-Particles 4.3.2 β-Particles 4.4 Interaction with Electromagnetic Radiation 4.4.1 Electromagnetic Radiation 4.4.2 Photoelectric Effect 4.4.3 Compton Effect 4.4.4 Pair Production 4.5 Consequences of Interactions 4.5.1 Process of Excitation 4.5.2 Process of Ionization 4.6 Types of Counters 5 Ionization Counters 5.1 Introduction 5.2 Ionization Counter 5.3 General Design of an Ionization Chamber 5.3.1 Current–Voltage Characteristics of the Ionization Chamber 5.4 Nature of Gas to be Used in Ionization Chamber 5.5 Regions Suitable for Counting Purposes 5.6 Nature of Pulses Produced in Ionization Chamber 5.6.1 Conversion of Triangular Pulses to Square Type Pulses 5.6.2 Pulses Due to α- and β-Particles 5.6.3 Relationship Between Energy of Radiation and Pulse Height 5.7 Ionization Counters 5.8 Proportional Counter 5.8.1 Design of a Gas Flow Proportional Counter 5.8.2 Process of Ion-Pair Formation 5.8.3 Operating Condition 5.8.4 Type of Radioactivity Measurable by the Counter 5.8.5 Background Counting 5.8.6 Pulse Height Analyzer in Proportional Counter 5.8.7 Advantages of Gas Flow Proportional Counter 5.9 Geiger–Müller Counter (G.M. Counter) 5.9.1 Design of the End-Window G.M. Counter 5.9.2 Principle of a G.M. Counter 5.10 Liquid Geiger–Müller Counter 5.10.1 The Assembly of the Liquid G.M. Counter 5.10.2 Thickness of the Window and Density Correction 5.10.3 Necessary Precautions While Using Liquid G.M. Counter 5.11 Current–Voltage Characteristics of the G.M. Counter 5.12 Dead Time of Geiger–Müller Counter 5.12.1 What is a Dead Time? 5.12.2 Impact of Dead Time on the Anode 5.12.3 Correction of Lost Counts 5.12.4 Determination of Dead Time of the Counter 5.13 Chemically Quenched G.M. Counter 5.13.1 Organic Gas Quenched G.M. Counter 5.13.2 Halogen Quenched G.M. Counter 5.14 Window Thickness 5.15 Limitations of Ionization Counters 6 Scintillation Counter 6.1 Introduction 6.2 Scintillation Counter 6.3 Principle of Scintillation Counter 6.4 Components of a Scintillation Counter 6.5 Design of Photomultiplier Tube 6.6 Scintillator 6.6.1 Inorganic Scintillator 6.6.2 Organic Scintillator 6.6.3 Composition of Scintillator 6.7 Precautions Liquid Scintillation 6.7.1 Size of the Sample Holder 6.7.2 Composition of Sample for Counting 6.8 Gel Scintillator 6.9 Filter Paper Soaked with Scintillator 6.10 Parameters Controlling The Scintillation Counter 6.10.1 γ-radiations 6.10.2 β-particulate Radiations 6.10.3 α-particulate Radiations 6.11 Optimum Conditions for Counting 6.11.1 Calibration of Pulse Height Analyzer 6.12 β-counting 6.12.1 Counting Conditions for β-particles 6.13 Quenching Corrections 6.13.1 Internal Standard Technique 6.13.2 Channel Ratio Technique 6.13.3 External Standard Source Techniques 6.14 Effect of Multiple Type Radiations on Counting 7 Non-conventional Detection Techniques 7.1 Introduction 7.2 Semiconductor Detector 7.3 Principle of Semiconductor Detectors 7.3.1 Formation of Band Gap 7.3.2 Fermi Energy in a Material 7.3.3 n- and p-Type Materials 7.4 Formation of p:p Junction 7.4.1 Formation of Space Charge Region 7.4.2 Distribution of Carrier Concentration 7.4.3 p-n Junction vis-a-vis Diode 7.5 Effect of Radiation on the p-n Junction 7.5.1 Design of a Semiconductor Detector 7.5.2 Advantage of a Semiconductor Detector 7.6 Silicon- and Germanium Lithium-Drifted Detectors 7.7 Nuclear Emulsion Techniques 7.7.1 Silver Grains in Photographic Plate by α-Particles 7.7.2 X-ray Film Badges 7.7.3 Emulsion Radio Chromatography 7.8 Solid-State Track Detector 7.9 Low-Level Counting 7.9.1 Anti-coincidence Counting System 7.9.2 Co-incidence Counting System 8 Sample Preparation for Counting 8.1 Sample Preparation Techniques 8.1.1 Counting of Solutions 8.1.2 Counting in Form of Suspension 8.1.3 Counting by Spreading Sample over a Filter Paper 8.1.4 Deposition of Sample by Electrolysis 8.1.5 Vacuum Evaporation Technique 8.1.6 Electrospraying Technique 8.2 Solid Sample Source 8.2.1 Planchet Material 8.2.2 Preparation of Solid Sample from Liquid Sample 8.2.3 Source from a Slurry 9 Factors Affecting the Counting Efficiency 9.1 Introduction 9.2 Geometrical Efficiency 9.2.1 Self-absorption 9.2.2 Backscattering 9.2.3 External Absorption 9.2.4 Background Activity 9.3 Decay Scheme 9.3.1 Tritium 9.3.2 Sodium-22 9.3.3 Sodium-24 9.3.4 Strontium-90 9.3.5 Cesium-137 10 Identification of Radioactive Isotopes 10.1 Introduction 10.2 Counter Selection 10.3 Energy Determination 10.4 β-Spectrometry 10.4.1 β-Absorption Law and Its Spectrum 10.4.2 Feather Analysis 10.4.3 Graphical Absolute Method 10.4.4 Determination of Emax 10.5 Determination of Energy of α-Particles or γ-Rays 10.6 Photographic Emulsion Technique 10.7 Half-Thickness 10.8 Half-Life Determination 11 Statistics of Counting 11.1 Introduction 11.2 Statistical Error in Counting 11.3 Gaussian Distribution Curve 11.3.1 Standard Deviation 11.3.2 Advantages of Standard Deviation Calculation 11.3.3 Representation of Activity 11.4 Sums and Differences of Counts 11.5 Multiplication or Division to Recorded Count 11.5.1 Division by a Constant Factor 11.5.2 Multiplication by Another Count 12 Health Hazards and Protection 12.1 Introduction 12.2 Biological Effect of Radiation 12.3 External Exposure 12.4 Internal Absorption 12.5 Units of Radiation Dose 12.5.1 Curie 12.5.2 Rad 12.5.3 Rem 12.5.4 Maximum Permissible Level 12.5.5 Maximum Permissible Level of External Radiation 12.5.6 Maximum Permissible Body Burden 12.5.7 Dose Rate Calculation 12.6 Protection from External Hazard 12.6.1 Distance 12.6.2 Shielding 12.6.3 Time 12.7 Instruments for Detection and Measurement of Radiation 12.7.1 Portable Hand Monitor 12.7.2 Pocket Dosimeter 12.7.3 Photographic Film Badge 12.7.4 Monitors for Survey Work 12.8 Design of a Radioactive Tracer Suit 12.9 Decontamination of Apparatus 12.9.1 Process of Decontamination 12.9.2 Disposal of Radioactive Waste 12.10 Discipline in the Radioactive Laboratory 13 Radiochemical Separation Techniques 13.1 Introduction 13.2 Separation and Purification Techniques 13.3 Co-precipitation 13.3.1 Carriers for the Separation 13.3.2 Condition for Effective Use of Carrier 13.4 Solvent Extraction 13.5 Electrochemical Methods 13.6 Volatilization and Distillation 13.7 Chromatography 13.7.1 Paper Chromatography 13.7.2 Paper Electrophoresis 13.7.3 Ion-Exchange Method 13.7.4 Nuclear Recoil-Method 13.8 Activation Analysis 13.8.1 Theory of the Activation Analysis Technique 13.8.2 Experimental Procedures 13.8.3 Advantages/Disadvantages of This Technique 14 Hot Atom-Nuclear Reaction 14.1 Introduction 14.2 Szilard-Chalmers Reactions 14.2.1 Szilard-Chalmers Reaction with Organic Substances 14.2.2 Szilard-Chalmers Reaction with Inorganic Substances 14.3 Application of Szilard-Chalmers Reactions Appendix Problem References Index