Book contents
- Front Matter
- Contents
- Preface to the second edition
- Preface to the first edition
- Acknowledgements
- 1 Historical introduction
- 2 The continuous X-ray spectrum
- 3 Characteristic X-rays
- 4 Experimental techniques for the study of X-rays
- 5 The absorption and scattering of X-rays
- 6 X-ray production by protons, α-particles and heavy ions
- 7 X-rays in radioactive decay
- 8 Some additional fields of X-ray study
- Appendix 1 Range–energy relations, etc., for electrons
- Appendix 2 Experimentally determined mass attenuation coefficients
- Appendix 3 Decay schemes of some radionuclides
- Appendix 4 Absorption edges and characteristic emission energies in KeV
- Appendix 5 K-shell fluorescence yields
- Bibliography
- Index
3 - Characteristic X-rays
Published online by Cambridge University Press: 22 September 2009
- Front Matter
- Contents
- Preface to the second edition
- Preface to the first edition
- Acknowledgements
- 1 Historical introduction
- 2 The continuous X-ray spectrum
- 3 Characteristic X-rays
- 4 Experimental techniques for the study of X-rays
- 5 The absorption and scattering of X-rays
- 6 X-ray production by protons, α-particles and heavy ions
- 7 X-rays in radioactive decay
- 8 Some additional fields of X-ray study
- Appendix 1 Range–energy relations, etc., for electrons
- Appendix 2 Experimentally determined mass attenuation coefficients
- Appendix 3 Decay schemes of some radionuclides
- Appendix 4 Absorption edges and characteristic emission energies in KeV
- Appendix 5 K-shell fluorescence yields
- Bibliography
- Index
Summary
Energy levels and X-ray spectra from singly-ionized atoms
Soon after the discovery of X-rays, attempts were made to investigate the spectral characteristics of the radiation. Crystal diffraction had not yet been discovered, but by studying the absorption of the radiation by successive layers of material it was established that the radiation consisted of a continuous spectrum (discussed in the previous chapter), and also a monoenergetic component, or ‘line’ spectrum (soon to be found to consist of several lines) the penetrating power of which depended markedly on the target element. This ‘characteristic’ radiation has been the subject of much study, and can be understood in considerable detail from the Bohr theory of the atom as elaborated by Sommerfeld and others. The development of wave mechanics added to this understanding and enabled a detailed interpretation of the fine structure of spectra to be built up. The classification of the orbital electrons into shells and the designation of individual electrons by means of quantum numbers are well-known features of the Bohr theory. Fig. 3.1 shows how the orbital electrons may be grouped together into the K, L, M etc. shells of progressively decreasing binding energy, and it is seen that (with the exception of the K shell) each shell consists of several sub-shells of slightly different energy.
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- X-rays in Atomic and Nuclear Physics , pp. 62 - 135Publisher: Cambridge University PressPrint publication year: 1990