1. 4/2003 Rev 2 I.2.2 – slide 1 of 13 Part I Review of Fundamentals Module 2Basic Physics and Mathematics Used in Radiation Protection Session 2Excitation and Ionisation Session I.2.2 IAEA Post Graduate Educational Course Radiation Protection and Safe Use of Radiation Sources

2. 4/2003 Rev 2 I.2.2 – slide 2 of 13  In this session we will discuss Electron Shells  We will discuss the Binding Energy which holds the electrons to the nucleus  We will discuss Excitation and Ionization which are processes by which electrons are removed from their stable location Overview

3. 4/2003 Rev 2 I.2.1 – slide 3 of 29 ELECTRON SHELLS AND BINDING ENERGY  Electrons exist in discrete “shells” around the nucleus (similar to planets around the sun)  Each shell represents a unique binding energy holding the electron to the nucleus  The shells are designated by letters (K, L, M, N …) where K, the shell closest to the nucleus, has the largest binding energy, so the K electron is the most tightly bound  Maximum number of electrons in each shell: 2 in K shell, 8 in L shell …

4. 4/2003 Rev 2 I.2.2 – slide 4 of 13 Electron Shells

5. 4/2003 Rev 2 I.2.2 – slide 5 of 13 2n 2 Shelln Maximum No. of Electrons K12 L28 M318 N432 O550 P672 Electron Shells K L M N O

6. 4/2003 Rev 2 I.2.2 – slide 6 of 13 ShellHydrogenTungsten K-13.5-69,500 L-3.4-11,280 M-1.5-2,810 N-0.9-588 O-0.54-73 Binding Energy (Binding Energy in eV)

7. 4/2003 Rev 2 I.2.2 – slide 7 of 13 Binding Energy 10 30 40 50 60 70 100 80 9011020 5060708090100102030400 0 Atomic Number (Z) Binding Energy (keV)

8. 4/2003 Rev 2 I.2.2 – slide 8 of 13 Excitation electron orbitals excited state ground state energy nucleus atom energy

9. 4/2003 Rev 2 I.2.2 – slide 9 of 13 normal energy level higher energy level excited electron energy Excitation

10. 4/2003 Rev 2 I.2.2 – slide 10 of 13 nucleus electron energy excited state Excitation

11. 4/2003 Rev 2 I.2.2 – slide 11 of 13 Excitation

12. 4/2003 Rev 2 I.2.2 – slide 12 of 13 Ionization Ionization of an outer shell electron

13. 4/2003 Rev 2 I.2.2 – slide 13 of 13 Ionization Ionization of a K-shell electron

14. 4/2003 Rev 2 I.2.2 – slide 14 of 13 Where to Get More Information  Cember, H., Johnson, T. E., Introduction to Health Physics, 4 th Edition, McGraw-Hill, New York (2008)  Martin, A., Harbison, S. A., Beach, K., Cole, P., An Introduction to Radiation Protection, 6 th Edition, Hodder Arnold, London (2012)  Jelley, N. A., Fundamentals of Nuclear Physics, Cambridge University Press, Cambridge (1990)  Firestone, R.B., Baglin, C.M., Frank-Chu, S.Y., Eds., Table of Isotopes (8 th Edition, 1999 update), Wiley, New York (1999)