Chronic Radiation Hazards

Preface

Acknowledgments

I. Experimental Design


1. Introduction


2. Choice of Animal


3. Choice of Dose Rate


4. Continuity of Irradiation


5. Contaminating Radiations


6. Animal Care


7. Observation of Radiation Effects


8. General Structural Lay-out


9. The Radiations in the Tanks

(i) Fast Neutron Radiation

(ii) Background Fast Neutron Radiation

(iii) Thermal Neutrons

(iv) Gamma Radiation


10. Dose Levels in the Tanks


11. The Energy of the Neutrons


12. Dose Distribution in the Mouse

II. Dosimetry


1. Introduction


2. Interaction of Neutrons with Light Elements


3. Energy Absorption Due to Fast Neutrons

(i) Elastic Scattering of Fast Neutrons

(ii) Inelastic Scattering and Nuclear Reactions of Fast Neutrons


4. Energy Absorption Due to Slow Neutrons


5. Energy Absorption Due to Gamma Rays


6. Principle of Method of Measurement of Fast Neutron Dose


7. Ionization-dose Relations for Fast Neutrons

(i) Homogeneous Acetylene and Tissue Chambers

(ii) Non-homogeneous Chambers


8. Ionization-flux Relations for Slow Neutrons

(i) Boron Trifluoride Chamber

(ii) Magnesium-argon Chamber

(iii) Acetylene Chamber

(iv) Tissue Chamber

(v) Relative Ionizations by Fast and Slow Neutrons


9. Ionization-dose Relations for Gamma Rays


10. Attenuation of Radiations in the Chamber Walls


11. Expressions for Fast Neutron and Gamma Ray Dose Rates and for Slow Neutron Flux


12. Accuracy of the Estimates of Dose Rate

(i) Fast Neutron Dose Rate

(ii) Gamma Ray Dose Rate

(iii) Slow Neutron Flux


13. Comparison of the Fast Neutron Dose Rates from Observations with Acetylene, Tissue and Aluminum-argon Chambers


14. Apparatus and Experimental Procedures

(i) The Ionization Chambers

(ii) Ionization Current Measurement

(iii) Saturation Curves

(iv) Calibration of the Chambers


15. Energy of the Gamma Rays in the Irradiation Tanks

(i) Experimental Details

(ii) Results


16. Energy Loss per Ion Pair in Gases

(i) Experimental Work since 1944

(ii) Energy per Ion Pair in Argon

(iii) Energy per Ion Pair in Acetylene

(iv) Energy per Ion Pair in Nitrogen, Oxygen, Air, Carbon Dioxide, Water Vapor and Boron Trifluoride

(v) General Conclusions for Pure Gases

(vi) Ionization by Neutron Recoils

(vii) Energy per Ion Pair in Gas Mixtures


17. Summary

Appendix. Ionization Currents in Chambers Exposed to Slow Neutrons

III. Results of Fast Neutron Irradiation


1. Records of Dosage and Environment

(i) Dosage

(ii) Environmental Temperature


2. Effects of Continued Exposure to Death

(i) Survival Times: Analysis and Interpretation

(ii) Body Weight

(iii) Causes of Death and Other Pathological Observations

(iv) Incidence of Tumors


3. Effects of Limited Exposure

(i) Hematology

(ii) Weights of Organs

(iii) Male and Female Fertility

(iv) Survival after Limited Exposures

(v) Observations on Mice Bred in the Irradiation Field

(vi) Testis Weight after a Single Dose of Fast Neutrons


4. Discussion


5. Summary

IV. Relative Biological Efficiency of Fast Neutrons and Gamma Rays for Chronic Exposures


1. Radiation Sources


2. Testis Weight


3. Male Fertility


4. Female Fertility


5. Hematological Changes


6. Weight of Spleen and Thymus


7. Discussion


8. Summary

General Summary and Conclusions

Glossary of Symbols

Index