Radiation Safety and You

1
Radiation Safety and You

• Brian Kessler
• Zettl Group Safety Talk
• September 7, 2006

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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 ?lt50 nm
• Non-Ionizing Radiation
• Radio waves, Micro waves, visible light
• Neutrons interact with nuclei

http//ehswprod.lbl.gov/EHSTraining/GERT/html/02wh
atis.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

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Dosage and How to Measure It

• Units
• Gray (Gy) J/kg, physical amount of energy
  absorbed
• Sievert (Sv) QNGy, biological effect of
  energy absorbed (1 Sv 100 rem)
• Quality Factor (Q) depends on the type of
  radiation
• photons, electrons Q1, Protons Q5, Alpha
  particles Q20
• N Factor (Q) depends on the exposed area
• Gonads, N0.20, Colon, Lung, Stomach N0.12,
  Bladder, Brain, Uterus, N 0.05, Skin N0.01

http//www.npl.co.uk/ionrad/quantities.html
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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/02wh
atis.html
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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/04ri
sks.html
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How to Protect Yourself

• ALARA A Low 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/rpmtrainingh
andout.pdf
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What You Should Do Now

• Review and Complete Your General Employee
  Radiation Training through LBL
• http//ehswprod.lbl.gov/EHSTraining/GERT/default.h
  tm
• Review Berkeley EHS Radiation Safety Website
• http//www.ehs.berkeley.edu/radsafety.html

Stay Safe!