1. 4/2003 Rev 2 I.4.11 – slide 1 of 21 Session I.4.11 Part I Review of Fundamentals Module 4Sources of Radiation Session 11X-Ray Production IAEA Post Graduate Educational Course Radiation Protection and Safe Use of Radiation Sources

2. 4/2003 Rev 2 I.4.11 – slide 2 of 21 Overview  In this session we will discuss how x-rays are produced  We will also discuss some of the characteristics of low energy x-ray machines  Finally, we will discuss x-ray production from linear accelerators and other machines

3. 4/2003 Rev 2 I.4.11 – slide 3 of 21 X-rays are useful for seeing what is inside of something Observation

4. 4/2003 Rev 2 I.4.11 – slide 4 of 21 As was discussed in Session I.2.3, x-rays are produced either as  characteristic x-rays (electron transition from one energy orbit around the atom to another orbit more tightly bound to the nucleus) or  bremsstrahlung (electrons losing energy as they pass in the vicinity of atoms and are deflected by the positive and negative charges) X-Rays

5. 4/2003 Rev 2 I.4.11 – slide 5 of 21  characteristic x-rays have defined predictable energies (the energy difference between the two orbits traversed by the electron)  bremsstrahlung is composed of a spectrum of energies ranging from near zero energy to a maximum energy equal to the initial energy of the electron – the energy of the x-ray produced is dependent on how much energy the electron loses during an interaction (the most it can lose is all the energy it has – the least it can lose is a very small amount, almost zero) X-Rays

6. 4/2003 Rev 2 I.4.11 – slide 6 of 21  characteristic x-rays are useful for identifying things  since the energies emitted are “characteristic” of the atoms that make up the object, an analysis of the energies emitted can help to identify the object  thus characteristic x-rays are used for trace element analysis which is used in forensic science (matching evidence samples) and other activities (such as identifying contaminants) X-Rays

7. 4/2003 Rev 2 I.4.11 – slide 7 of 21  bremsstrahlung x-rays are extensively used in medical and industrial applications  Medical x-ray units are used for Diagnostic Radiology and Linear Accelerators are used for Radiation Therapy  Industrial x-ray units are used to “diagnose” problems with inanimate objects (such as faulty welds on pipes) or they can be used to search for contraband (baggage inspection units at airports) X-Rays

8. 4/2003 Rev 2 I.4.11 – slide 8 of 21 Medical Diagnostic(portable)

9. 4/2003 Rev 2 I.4.11 – slide 9 of 21 Diagnostic Medical X-Ray Unit

10. 4/2003 Rev 2 I.4.11 – slide 10 of 21 Diagnostic Medical X-Ray Unit HIGH VOLTAGE CABLES X-RAY TUBE HOUSING (ASSEMBLY) COLLIMATOR

11. 4/2003 Rev 2 I.4.11 – slide 11 of 21 Diagnostic X-Ray Spectra

12. 4/2003 Rev 2 I.4.11 – slide 12 of 21 Medical Dental(diagnostic)

13. 4/2003 Rev 2 I.4.11 – slide 13 of 21 Superficial Therapy (low energy) Medical

14. 4/2003 Rev 2 I.4.11 – slide 14 of 21 Radiotherapy (high energy) Accelerates electrons but can also produce high energy x-rays by directing the electron beam into a target as is done in a typical diagnostic x-ray unit. Medical

15. 4/2003 Rev 2 I.4.11 – slide 15 of 21 X-Ray Unit

16. 4/2003 Rev 2 I.4.11 – slide 16 of 21 Megavoltage X-ray LINAC target electrons x-rays

17. 4/2003 Rev 2 I.4.11 – slide 17 of 21 x-rays produced from high energy electrons impinging on a target tend to be scattered in the forward direction x-rays produced by lower energy electrons tend to be scattered at right angle to the direction of the electron beam X-Ray Emission

18. 4/2003 Rev 2 I.4.11 – slide 18 of 21 Industrial X-Ray Diffraction

19. 4/2003 Rev 2 I.4.11 – slide 19 of 21 Industrial Radiography

20. 4/2003 Rev 2 I.4.11 – slide 20 of 21 For comparison, the output of a 100 Ci 192 Ir Radiography Source is about 47 R/hr @ 1 m Industrial Some typical radiation output measurements from industrial radiography units with beryllium windows X-Ray UnitkVpmA  R hr -1 @ 1 m Magnaflux150103,600 Sperry275106,600

21. 4/2003 Rev 2 I.4.11 – slide 21 of 21 Where to Get More Information  Cember, H., Introduction to Health Physics, 3 rd Edition, McGraw-Hill, New York (2000)  Firestone, R.B., Baglin, C.M., Frank-Chu, S.Y., Eds., Table of Isotopes (8 th Edition, 1999 update), Wiley, New York (1999)  International Atomic Energy Agency, The Safe Use of Radiation Sources, Training Course Series No. 6, IAEA, Vienna (1995)