Radiation Safety and You Brian Kessler Zettl Group Safety Talk September 7, 2006.
-
Upload
clifford-tucker -
Category
Documents
-
view
213 -
download
0
Transcript of Radiation Safety and You Brian Kessler Zettl Group Safety Talk September 7, 2006.
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 – 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
Radiation Producing Machines in the Lab
• Transmission Electron Microscope– Electrons, Secondary
X-Rays
• Scanning Electron Microscope– Electrons, Secondary
X-Rays
• Electron Beam Evaporator
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
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
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
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/rpmtraininghandout.pdf
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!