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29 Cards in this Set
- Front
- Back
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Ionizing radiation is defined as
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Photons or particles with enough energy to remove electrons from atoms of air (gases)
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The data on human health effects are due to the following (3 terms)
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- External X radiation
- External gamma radiation - Internal alpha radioactivity |
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what is the most quantitative estimates of health detriments for humans and animals
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Ionizing radiation
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atoms resulting from separated electrons
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- ions
- radiation is ionized air |
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Ionizing Radiation (IR)
(5 types) |
- “Hard” Xrays
- Gamma rays - Alpha particles - Beta particles - Muons and other cosmic radiation |
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Major health effects of radiation
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- Cancer
- Some heart, digestive disease in bomb survivors, only at high dose levels |
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(Radiation/Radioactivity Studies)
Radium dial painters |
Radium
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(Radiation/Radioactivity Studies)
Atom bomb survivors were exposed to what |
Radium
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(Radiation/Radioactivity Studies)
Ankylosing spondylitis patients were exposed to |
X-radiation
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(Radiation/Radioactivity Studies)
Tinea capitis patients were exposed to |
X-radiation
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(Radiation/Radioactivity Studies)
Uranium miners are exposed to |
Radon and progeny radiation
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20 domestic studies of normal
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Radon background
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Natural Background Radiation Exposure
- Substantial or unsubstantial? - Extent of radiation to global population from natural radiation and radioactivity appreciated only within last _______ years |
- Natural Background Radiation Exposure is substantial
- Appriciated only with in the last 20 years |
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% of Natural radiation exposure in the united States
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71
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% of Man-Made radiation in the United States
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29
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Four main types of radiation
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- Alpha particles -α
- Beta particles - β - Gamma rays - γ - X-rays - χ |
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Types of decay
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- α decay – 2 protons and 2 neutrons
- β decay – 1 electron from the nucleus (e-) |
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γ radiation occurs when
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nucleus releases excess energy (after α, β, or positron transition [e+])
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X radiation occurs when
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inner-shell orbital electron is removed and rearrangement of atomic electrons results energy released
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Radioactive Decay Rate Formula
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Activity (A) = λN
λ= ln(2)/ t1/2 Where: A = decay rate at time t = λN Ao = Initial decay rate λ= decay constant = ln(2)/ t1/2 N = number of atoms in the source |
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Exponential Radioactive Decay Law
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A = Ao e^(-λt)
Where A = Activity at time t Ao = Original activity Λ = decay constant = ln(2)/ t1/2 T = time since decay began until A |
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Energy of radiation
(Kinetic energy or potential energy) |
Kinetic energy
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(Energy of radiation)
α particles |
- E = ½ mV^(2)
- 4 – 8 MeV |
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(Energy of radiation)
β particles |
- β travels near speed of light, -- requires relativistic correction
E = 0.511 MeV |
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(Energy of radiation)
γ and x radiation |
Pure electromagnetic radiation
E = hν Where h = Planck’s constant = 6.626 x 10^(-34) J s ν = frequency of the radiation |
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(α Particles)
Each particular α is ______ (different energies or single energy) |
Monoenergetic
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(α Particles)
Charge |
2+ Charge
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(α Particles)
mass reletive to β particles |
7300 times mass of β particles
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(α Particles)
- Range in air - Range in tissue |
Air
- 0.325 E^(3/2) - For 226Ra, Range (air) = 3.4 cm Tissue - 1/1000 of range (air) - For 226Ra, Range (tissue) = 34 μm |
