x CONTENTS 



7. Radioactivity 163 



7.1. Summary of radioactivity — 7.2. Law of radioactive decay — 7.3. Fluctuations 



— 7.4. Simple decay — 7.5. Growth of radioactivity — 7.6. Radioactive substance 

 produced by parent of long half -life — 7.7. Parent and daughter substance of com- 

 parable half-lives — 7.8. Decay of nth. component in a radioactive chain — 7.9. 

 Radioactivity units — 7.10. Decay schemes — 7.11. The natural radioactive series. 

 — 7.12. Seaborg and Perlman table of isotopes. 



Part II. Methods and Instruments 



8. Indirect Methods for Measuring Deuterium 263 



8.1. Introduction — 8.2. Phyical properties of deuterium oxide and water — 8.3. 

 Preparation and purification of water samples for analysis — 8.4. Refractive index 



— 8.5. Pycnometer — 8.6. Free float — 8.7. Falling drop — 8.8. Diffusion gradient. 



9. Mass Spectrographs 279 



9.1. Aston mass spectrograph — 9.2. Dempster mass spectroscope — 9.3. 60-degree 

 (Nier-type) mass spectrometer — 9.4. Mattauch double-focusing spectrograph — 

 9.5. Dempster double-focusing spectrograph — 9.6. Bainbridge-Jordan double- 

 focusing mass spectrograph — 9.7. Trochoidal trajectory mass spectrograph — 

 9.8. Ion sources — 9.9. Detector requirements — 9.10. Photographic plates — 9.11. 

 Electrical devices — 9.12. Mass spectrometer recording systems — 9.13. Mass spec- 

 trometer errors — 9.14. Hydrogen — 9.15. Carbon — 9.16. Nitrogen — 9.17. Oxygen. 



10. Geiger-Miiller Counters 304 



10.1. General properties — 10.2. Non-self-quenching counters — 10.3. Self-quenching 

 counters — 10.4. Pulse and voltage characteristics — 10.5. Filling gases — 10.6. 

 Counter tube life — 10.7. Low-voltage counter tubes — 10.8. Active gas-filled 

 counters — 10.9. Neutron counters — 10.10. Slow neutron counters — 10.11. Fast 

 neutron counters — 10.12. Accuracy of counting measurements — 10.13. Average 

 deviation — 10.14. Standard deviation — 10.15. Probable error — 10.16. Counter 

 resolving time — 10.17. Coincidence correction for high counting rates — 10.18. 

 Coincidence counting corrections — 10.19. Counting efficiency — 10.20. Averaging 

 effect of scaling circuit — 10.21. Quenching circuits — 10.22. Scaling circuits — 

 10.23. Discriminators — 10.24. Recording circuits — 10.25. Coincidence circuits — 

 10.26. Counting rate meter. 



11. Proportional Counters 341 



11.1. General features and use — 11.2. Theory of operation. 



12. Ionization Chambers 344 



12.1. Description — 12.2. Applications — 12.3. Charge measuring instruments — 

 12.4. Statistics of measurements. 



13. Standardization of Radioactive Samples 358 



13.1. Introduction — 13.2. General methods — 13.3. Primary alpha-particle stand- 

 ards — 13.4. Standards for beta and gamma emitters — 13.5. Standardization by 

 coincidence measurements — 13.6. Long-life beta standards — 13.7. Beta-particle 

 standardization by direct measurement of the charge of the particles — 13.8. Indi- 

 rect standardization by calorimetric measurement of the total energy — 13.9. 

 Ionization measurement of beta and gamma rays — 13.10. Standardization of beta- 



