Book contents
- Frontmatter
- Contents
- Preface to the second edition
- Preface to the first edition
- Constants of nature, conversion factors and notation
- Glossary of some important symbols
- 1 Prologue
- 2 Leptons and the electromagnetic and weak interactions
- 3 Nucleons and the strong interaction
- 4 Nuclear sizes and nuclear masses
- 5 Ground-state properties of nuclei: the shell model
- 6 Alpha decay and spontaneous fission
- 7 Excited states of nuclei
- 8 Nuclear reactions
- 9 Power from nuclear fission
- 10 Nuclear fusion
- 11 Nucleosynthesis in stars
- 12 Beta decay and gamma decay
- 13 Neutrinos
- 14 The passage of energetic particles through matter
- 15 Radiation and life
- Appendix A Cross-sections
- Appendix B Density of states
- Appendix C Angular momentum
- Appendix D Unstable states and resonances
- Further reading
- Answers to problems
- Index
14 - The passage of energetic particles through matter
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface to the second edition
- Preface to the first edition
- Constants of nature, conversion factors and notation
- Glossary of some important symbols
- 1 Prologue
- 2 Leptons and the electromagnetic and weak interactions
- 3 Nucleons and the strong interaction
- 4 Nuclear sizes and nuclear masses
- 5 Ground-state properties of nuclei: the shell model
- 6 Alpha decay and spontaneous fission
- 7 Excited states of nuclei
- 8 Nuclear reactions
- 9 Power from nuclear fission
- 10 Nuclear fusion
- 11 Nucleosynthesis in stars
- 12 Beta decay and gamma decay
- 13 Neutrinos
- 14 The passage of energetic particles through matter
- 15 Radiation and life
- Appendix A Cross-sections
- Appendix B Density of states
- Appendix C Angular momentum
- Appendix D Unstable states and resonances
- Further reading
- Answers to problems
- Index
Summary
In this chapter we consider the passage of energetic particles through matter. Nuclear reactions usually result in the production of such particles: α-particles, electrons, photons, nucleons, fission fragments, or whatever. In passing through matter, an energetic particle loses its energy, ultimately largely into ionisation. The instruments of nuclear physics are designed to detect and measure this deposited energy, and so it is upon these processes that our knowledge of nuclear physics rests.
The subject is also basic to an understanding of the biological effects of energetic particles, since a living cell can be damaged by the ionisation. This can be of positive benefit, as in the destruction of malignant tissue in cancer treatment, or a danger from which, for example, workers in the nuclear power industry must be shielded. Shielding calculations also depend on the physical principles set out in this chapter.
We limit the discussion to particles with kinetic energies up to around 10 MeV, in line with the nuclear physics described in Chapters 4–12. It is intended to give the reader a qualitative comprehension, rather than a compendium of the most accurate formulae and data available for quantitative work.
Charged particles
We consider first the passage of charged particles, such as protons and α-particles, through gases. For charged particles of energy < 10 MeV, the dominant mechanism for energy loss is the excitation or ionisation of the atoms (or molecules) of the gas: electrons being excited to higher bound energy levels in the atom, or detached completely.
- Type
- Chapter
- Information
- An Introduction to Nuclear Physics , pp. 199 - 213Publisher: Cambridge University PressPrint publication year: 2001