Ionising radiation

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

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  • The time taken for the activity of a radionuclide to lose half its value by decay
  • The time taken for the activity of a radionuclide to lose half its value by decay
  • http://www.sxc.hu/
  • http://www.chemistryexplained.com/images/chfa_04_img0782.jpg
  • X-raysMedical imaging – radionuclides as markersCancer treatments
  • http://kilby.sac.on.ca/physics/sph3u/1a-Nuclear/NonMedicalUses/nonmedicaluses.htm
  • The traditional unit of activity has been the Curie (Ci), where one Curie = 3.7 x 1010 disintegration's per second.
  • The traditional unit of absorbed dose is the rad, where 1 Gray = 100 rads.
  • A unit of ionising radiation absorbed dose equivalent obtained as a product of the absorbed dose measure in grays and a dimensionless factor, stipulated by the International Commission on Radiological Protection (ICRP), and indicating the biological effectiveness of the radiation.Modifying factor depends on quality of radiation and part of body affected
  • “The quantity obtained by multiplying the absorbed dose by a factor to allow for the different effectiveness of the various ionising radiations in causing harm to tissue. Unit sievert, symbol Sv.” (HPA glossary http://www.hpa-radiationservices.org.uk/rpa/glossary/)Modifying factor depends on type of radiation
  • Modifying factor depends on part of body affected and type of organism“The quantity obtained by multiplying the equivalent dose to various tissues and organs by a weighting factor appropriate to each and summing the products. Unit sievert, symbol Sv. Frequently abbreviated to dose.” (HPA glossary http://www.hpa-radiationservices.org.uk/rpa/glossary/)
  • A unit of ionising radiation absorbed dose equivalent obtained as a product of the absorbed dose measure in grays and a dimensionless factor, stipulated by the International Commission on Radiological Protection (ICRP), and indicating the biological effectiveness of the radiation.Modifying factor depends on quality of radiation and part of body affected
  • Effective dose factors for specific tissuesICRP lists tissue weighting factors in Table 3, page 65, of Publication 103
  • Photo credit http://www.flickr.com/photos/redfiremg/3952257530/sizes/z/in/photostream/
  • Picture credit: http://www.bbc.co.uk/schools/gcsebitesize/science/images/ph_radio10.gif
  • Ionising radiation

    1. 1. Ionising Radiation<br />
    2. 2. Ionising Radiation<br />Particles and electromagnetic radiation <br />released by the decay of unstable atoms<br />
    3. 3. Ionising Radiation<br />Alpha particles<br />Beta particles<br />Neutrons<br />Gamma rays<br />X rays<br />
    4. 4. Ionising Radiation<br />Alpha particles<br />Beta particles<br />Neutrons<br />Gamma rays<br />X rays<br />Radionuclides<br />
    5. 5. Ionising Radiation<br />Alpha particles<br />Beta particles<br />Neutrons<br />Gamma rays<br />X rays<br />Elecromagnetic<br />radiation<br />
    6. 6.
    7. 7. Non - Ionisng<br />Ionising<br />
    8. 8. Half - life<br />The time taken for the activity of a radionuclide to decay by half its value<br />
    9. 9. Half - life<br />Isotope Half-Life <br />Tritium 12.4 y <br />Carbon 14 5730 y <br />Sulphur 35 87.4 d <br />Phosphorus 33 25.6 d <br />Phosphorus 32 14.3 d <br />Iodine 125 60.1 d<br />
    10. 10. What is radiation used for?<br />
    11. 11. Power generation<br />
    12. 12. Laboratories<br />
    13. 13. Radioactive tracers<br />
    14. 14. Medical<br />
    15. 15. Thickness gauges<br />
    16. 16. Units<br />
    17. 17. Activity (Becquerel)<br />1 Becquerel = 1 disintegration per second<br />
    18. 18. Absorbed Dose (gray)<br />1gray (Gy) = energy absorption of 1 joule/Kg<br />
    19. 19. Dose Equivalent (sievert)<br />Equivalent dose (Sv) = Absorbed dose (Gy) x Q <br />
    20. 20. Dose Equivalent (sievert)<br />Equivalent dose (Sv) = Absorbed dose (Gy) x Q <br />Q is "quality factor“, dependent upon radiation type<br />
    21. 21.
    22. 22. Effective Dose<br />Effective dose = Equivalent dose (Sv) x N <br />
    23. 23. Effective Dose<br />Effective dose = Equivalent dose (Sv) x N <br />N is weighting factor dependent upon tissue type<br />
    24. 24.
    25. 25. Annual dose limits for employees and members of the public<br />Regulation 11 of Ionising Radiations Regulations 1999<br />
    26. 26. Geiger Counter<br />
    27. 27.
    28. 28. Effects<br />
    29. 29. Alpha particles<br />Stopped by sheet of paper or skin<br />
    30. 30. Betaparticles<br />Stopped by few mm of aluminium<br />
    31. 31. Gamma rays<br />Stopped by several metres of concrete or cms of lead<br />
    32. 32.
    33. 33. Short term effects<br />Cellular damage<br />Radiation sickness<br />
    34. 34. Cancer<br />Genetic damage<br />Reproductive effects<br />Long term effects<br />
    35. 35. Internal Hazards<br />Exposure to radioactive particles by :<br />inhalation<br />ingestion<br />skin absorption / penetration<br />
    36. 36. Radiological risk<br />Dose (µSv)<br />Risk of Death<br />Living in Cornwall<br />7800<br />1 in 3,200<br />5000<br />1 in 5,000<br />Brain scan<br />2700<br />1 in 10,000<br />Average annual<br />1000<br />1 in 25,000<br />Radon<br />69<br />1 in 35,000<br />Transatlantic flight<br />46<br />1 in 500,000<br />Chernobyl<br />20<br />1 in 1.25 million<br />Chest X-ray<br />135 g brazil nuts<br />10<br />1 in 2.5 million<br />Source: Health Protection Agency<br />
    37. 37. Radiological Protection<br />
    38. 38. Containment<br />
    39. 39. Shielding<br />
    40. 40.
    41. 41. Distance<br />
    42. 42.
    43. 43. Restrict exposure duration and frequency<br />
    44. 44. Photo credits<br />www.chemistryexplained.com/images/chfa_04_img0782.jpg<br />www.bbc.co.uk/schools/gcsebitesize/science/images/ph_radio10.gif<br />www.flickr.com/photos/redfiremg/3952257530/sizes/z/in/photostream/<br />http://kilby.sac.on.ca/physics/sph3u/1a-Nuclear/NonMedicalUses/nonmedicaluses.htm<br />Stock.XCHNG (www.sxc.hu)<br />www.OHTA.net<br />
    45. 45. http://www.slideshare.net/mikeslater<br />occhygiene@btconnect.com<br />http://diamondenv.wordpress.com<br />Twitter @diamondenv<br />Mike Slater<br />
    46. 46. Mike Slater, Diamond Environmental Ltd. (occhygiene@btconnect.com)<br />This presentation is distributed under the Creative Commons<br />Attribution-NonCommercial-ShareAlike<br />UK:International Licence<br />

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