High Sensitivity Counting Techniques

Foreword Authors' Preface Acknowledgments Chapter 1. Counting Parameters 1.1 The Minimum Observable Counting Rate 1.2 The Factor of Merit References Chapter 2. The Attainment of Low Backgrounds in Radiation Detectors - (I) The Cosmic Radiation 2.1 Sources of Background 2.2 The Extensive Air Shower 2.3 Neutron Production 2.4 Gamma Shielding 2.5 Summary of Cosmic-ray Shield Requirements 2.6 Types of Anticoincidence System 2.7 Experimental Tests 1. Proportional Counting 2. Sodium Iodide Scintillation Counting 2.8 Conclusions on Shielding for 1. Gas Proportional and Geiger Counters 2. Sodium Iodide Crystals References Chapter 3. The Attainment of Low Backgrounds in Radiation Detectors - (II) Secondary Effects 3.1 Local Radioactivity 3.2 Construction Materials 3.3 Electronics and Electrical System 1. Amplifier Noise 2. Photomultiplier Noise 3. Amplifier Overload 4. Gamma Spectrometer Overload Pulse Inhibit Circuit 5. Cable Reflections 6. Pick-up from the Mains Supply, etc 7. E.H.T. Breakdown References Chapter 4. Low-Background Laboratories 4.1 Underground Laboratories 4.2 Steel Rooms 4.3 The Aldermaston Low-background Laboratory References Chapter 5. The Measurement of Weak Alpha Activities 5.1 General Considerations on Sensitivity 5.2 Scintillation Counting 1. ZnS(Ag) Phosphors 2. CsI(Tl) Scintillators 3. Thin Plastic Scintillators 4. The Wetted-anthracene Method for Counting Aqueous Sources 5. Loaded Liquid Scintillators 5.3 Gas-filled Detectors 1. Large Area Counter for Total Alpha Counting 2. Alpha Spectroscopy with Gas-filled lonization Chambers 5.4 The Gridded lonization Chamber 1. Electronic Collimation 5.5 The Coaxial-electrode lonization Chamber as an Alpha Spectrometer 1. Design of a Coaxial Chamber for Alpha Spectrometry 2. Description of Counter 5.6 Semiconductor Counters 5.7 Preparation of Sources 1. Electrodeposition 2. Lacquer Technique 3. Tetraethyleneglycol (TEG) Spread Sources 4. Evaporation of Organic Solutions 5. Vacuum Sublimation 6. Large Area Sources by Evaporation in Air 5.8 Self-absorption in Homogeneously Dispersed Sources 5.9 Distortion of Energy Spectrum of Alpha-particles from a Thick Source 5.10 Backscattering of Alpha-particles from the Source Backing References Chapter 6. Carbon-14 Beta Counting 6.1 Radiocarbon Dating 1. Introduction 2. Statistics of Carbon Dating 3. Solid Source Counters 4. Gaseous Source Counters 5. Liquid Scintillation Counting of Natural C14 6.2 Detection of Artificial C14 Activities 1. Solid Sources 2. Gaseous Sources 3. Liquid Sources 4. Ionization Chambers Bibliography and References Chapter 7. Counting of Soft Radiations Using Internal Sources 7.1 Counting of Tritium 1. Liquid Scintillation Counting 2. Gas Counting 7.2 Errors in Gas Counting Techniques 7.3 Electron Attachment in Counters 7.4 Counting of S35 7.5 High Temperature Gas Counters 7.6 Counting of Other Soft Beta-emitters 7.7 Detection of X-radiations from Low Z Isotopes 1. Solid Sources 2. Gaseous Sources Bibliography and References Chapter 8. Beta Counting of Solid and Liquid Sources 8.1 Systems with 4p Geometry 8.2 Systems with 2p Geometry 8.3 Systems with less than 2p Geometry 1. Loop Anode Proportional Counter with Geiger Ring 2. Multiple-anode Annular Counter System 3. Van Duuren Counter 8.4 Organic Scintillator Anticoincidence Shields 8.