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Radiation Safety and You

Radiation Safety and You. Brian Kessler Zettl Group Safety Talk September 7, 2006. Types of Radiation. Ionizing Radiation Ionization potentials of the elements range from 3.89 eV (Cs) to 24.6 eV (He) Alpha Rays – He 4 nucleas Beta Rays – electrons/positrons

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Radiation Safety and You

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  1. Radiation Safety and You Brian Kessler Zettl Group Safety Talk September 7, 2006

  2. Types of Radiation • Ionizing Radiation • Ionization potentials of the elements range from 3.89 eV (Cs) to 24.6 eV (He) • Alpha Rays – He4 nucleas • Beta Rays – electrons/positrons • X-rays and Gamma Rays - photons with λ<50 nm • Non-Ionizing Radiation • Radio waves, Micro waves, visible light • Neutrons – interact with nuclei http://ehswprod.lbl.gov/EHSTraining/GERT/html/02whatis.html

  3. Radiation Producing Machines in the Lab • Transmission Electron Microscope • Electrons, Secondary X-Rays • Scanning Electron Microscope • Electrons, Secondary X-Rays • Electron Beam Evaporator

  4. Dosage and How to Measure It • Units: • Gray (Gy) = J/kg, physical amount of energy absorbed • Sievert (Sv) = Q*N*Gy, biological effect of energy absorbed (1 Sv = 100 rem) • Quality Factor (Q) depends on the type of radiation • photons, electrons Q=1, Protons Q=5, Alpha particles Q=20 • N Factor (Q) depends on the exposed area • Gonads, N=0.20, Colon, Lung, Stomach N=0.12, Bladder, Brain, Uterus, N = 0.05, Skin N=0.01 http://www.npl.co.uk/ionrad/quantities.html

  5. Typical Exposure • Significant Background Sources of Radiation • Cosmic Rays, Radon Gas, Naturally Occuring Isotopes, Medical Diagnostics • Annual Dose: 2 mSv • Fly LA-NY: 0.025 mSv • GI X-Ray Series : 2.2 mSv http://ehswprod.lbl.gov/EHSTraining/GERT/html/02whatis.html

  6. Radiation Danger • Primary Risk - Cancer • Risk to General Population: 20% • Risk to individual with 100 mSv excess exposure: 20.4% • Secondary Risk – Genetic Effects • Increased Risk of Mental Retardation in Exposed Fetuses: 0.8% http://ehswprod.lbl.gov/EHSTraining/GERT/html/04risks.html

  7. How to Protect Yourself • ALARA – ALow As Reasonably Achievable • Minimize Time • Maximize Distance • Use Appropriate Shielding • Alpha Particles – a sheet of paper • Beta Particles – a sheet of metal • Gamma Rays – thick lead or concrete http://www.ehs.berkeley.edu/radsafety/rpmtraininghandout.pdf

  8. What You Should Do Now • Review and Complete Your General Employee Radiation Training through LBL: • http://ehswprod.lbl.gov/EHSTraining/GERT/default.htm • Review Berkeley EHS Radiation Safety Website: • http://www.ehs.berkeley.edu/radsafety.html Stay Safe!

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