Ionising radiation
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An introduction to ionising radiation. What is it?, units, measurement, health effects, control.
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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
- 7. Non - Ionisng Ionising
- 8. Half - life The time taken for the activity of a radionuclide to decay by half its value
- 9. 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
- 10. What is radiation used for?
- 11. Power generation
- 12. Laboratories
- 14. Medical
- 15. Thickness gauges
- 16. Units
- 17. Activity (Becquerel) 1 Becquerel = 1 disintegration per second
- 18. Absorbed Dose (gray) 1gray (Gy) = energy absorption of 1 joule/Kg
- 19. Dose Equivalent (sievert) Equivalent dose (Sv) = Absorbed dose (Gy) x Q
- 20. Dose Equivalent (sievert) Equivalent dose (Sv) = Absorbed dose (Gy) x Q Q is "quality factor“, dependent upon radiation type
- 22. Effective Dose Effective dose = Equivalent dose (Sv) x N
- 23. Effective Dose Effective dose = Equivalent dose (Sv) x N N is weighting factor dependent upon tissue type
- 25. Annual dose limits for employees and members of the public Regulation 11 of Ionising Radiations Regulations 1999
- 26. Geiger Counter
- 28. Effects
- 29. Alpha particles Stopped by sheet of paper or skin
- 30. Betaparticles Stopped by few mm of aluminium
- 31. Gamma rays Stopped by several metres of concrete or cms of lead
- 33. Short term effects Cellular damage Radiation sickness
- 34. Cancer Genetic damage Reproductive effects Long term effects
- 35. Internal Hazards Exposure to radioactive particles by : inhalation ingestion skin absorption / penetration
- 36. Radiological risk Dose (µSv) Risk of Death Living in Cornwall 7800 1 in 3,200 5000 1 in 5,000 Brain scan 2700 1 in 10,000 Average annual 1000 1 in 25,000 Radon 69 1 in 35,000 Transatlantic flight 46 1 in 500,000 Chernobyl 20 1 in 1.25 million Chest X-ray 135 g brazil nuts 10 1 in 2.5 million Source: Health Protection Agency
- 38. Containment
- 39. Shielding
- 41. Distance
- 43. Restrict exposure duration and frequency
- 44. 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
- 45. http://www.slideshare.net/mikeslater occhygiene@btconnect.com http://diamondenv.wordpress.com Twitter @diamondenv Mike Slater
- 46. Mike Slater, Diamond Environmental Ltd. (occhygiene@btconnect.com) This presentation is distributed under the Creative Commons Attribution-NonCommercial-ShareAlike UK:International Licence
Notas do Editor
- 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