Ionising radiation

An introduction to ionising radiation. What is it?, units, measurement, health effects, control.

1. Ionising Radiation

2. Ionising Radiation Particles and electromagnetic radiation released by the decay of unstable atoms

3. Ionising Radiation Alpha particles Beta particles Neutrons Gamma rays X rays

4. Ionising Radiation Alpha particles Beta particles Neutrons Gamma rays X rays Radionuclides

5. Ionising Radiation Alpha particles Beta particles Neutrons Gamma rays X rays Elecromagnetic radiation

6. Non - Ionisng Ionising

7. Half - life The time taken for the activity of a radionuclide to decay by half its value

8. Half - life Isotope Half-Life Tritium 12.4 y Carbon 14 5730 y Sulphur 35 87.4 d Phosphorus 33 25.6 d Phosphorus 32 14.3 d Iodine 125 60.1 d

9. What is radiation used for?

10. Power generation

11. Laboratories

12. Radioactive tracers

13. Medical

14. Thickness gauges

15. Units

16. Activity (Becquerel) 1 Becquerel = 1 disintegration per second

17. Absorbed Dose (gray) 1 gray ( Gy) = energy absorption of 1 joule/Kg

18. Dose Equivalent (sievert) Equivalent dose (Sv) = Absorbed dose (Gy) x Q

19. Dose Equivalent (sievert) Equivalent dose (Sv) = Absorbed dose (Gy) x Q Q is "quality factor“, dependent upon radiation type

20. Q Photons, all energies 1 Electrons and muons, all energies 1 Protons 2 Alpha particles and other atomic nuclei 20

21. Effective Dose Effective dose = Equivalent dose (Sv) x N

22. Effective Dose Effective dose = Equivalent dose (Sv) x N N is weighting factor dependent upon tissue type

23. N Bone marrow, colon, lung, breast, stomach 0.12 Gonads 0.08 Bladder, brain, salivary glands, kidney, liver, muscles, oesophagus, pancreas, small intestine, spleen, thyroid, uterus 0.05 Bone surface, skin 0.01

24. Dose Employees (age 18+) Trainees (age <18) Members of Public Effective dose 20 mSv 6 mSv 1 mSv Equivalent dose for eye 150 mSv 50 mSv 15 mSv Equivalent dose for skin 500 mSv 150 mSv 50 mSv Equivalent dose for the hands, forearms, feet and ankles 500 mSv 150 mSv 50 mSv Annual dose limits for employees and members of the public Regulation 11 of Ionising Radiations Regulations 1999

25. Geiger Counter

26. Effects

27. Alpha particles Stopped by sheet of paper or skin

28. Beta particles Stopped by few mm of aluminium

29. Gamma rays Stopped by several metres of concrete or cms of lead

30. Short term effects Cellular damage Radiation sickness

31. Cancer Genetic damage Reproductive effects Long term effects

32. Internal Hazards Exposure to radioactive particles by : inhalation ingestion skin absorption / penetration

33. Radiological risk Dose (µSv) Risk of Death Living in Cornwall Brain scan Average annual Radon Transatlantic flight Chernobyl Chest X-ray 135 g brazil nuts 7800 5000 2700 1000 69 46 20 10 1 in 3,200 1 in 5,000 1 in 10,000 1 in 25,000 1 in 35,000 1 in 500,000 1 in 1.25 million 1 in 2.5 million Source: Health Protection Agency

34. Radiological Protection

35. Containment

36. Shielding

37. Distance

38. Distance Dose rate (uSv/hr) 1 metre 1 2 metres 0.25 4 metres 0.06

39. Restrict exposure duration and frequency

40. Photo credits www.chemistryexplained.com/images/chfa_04_img0782.jpg www.bbc.co.uk/schools/gcsebitesize/science/images/ph_radio10.gif www.flickr.com/photos/redfiremg/3952257530/sizes/z/in/photostream/ http://kilby.sac.on.ca/physics/sph3u/1a-Nuclear/NonMedicalUses/nonmedicaluses.htm Stock.XCHNG (www.sxc.hu) www.OHTA.net

41. http://www.slideshare.net/mikeslater [email protected] http://diamondenv.wordpress.com Twitter @diamondenv Mike Slater

42. Mike Slater, Diamond Environmental Ltd. ([email protected]) This presentation is distributed under the Creative Commons Attribution-NonCommercial-ShareAlike UK:International Licence