Radiation Radiation “Awareness” “Awareness” Objectives Objectives • To increase public To increase public understanding of radiation understanding of radiation and radioactivity and radioactivity • To provide basic radiation- To provide basic radiation- science information for use science information for use by science teachers by science teachers Health Physics Society Health Physics Society
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Radiation “Awareness” Objectives To increase public understanding of radiation and radioactivityTo increase public understanding of radiation and radioactivity.
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Radiation “Awareness”Radiation “Awareness”
ObjectivesObjectives
• To increase public understanding of To increase public understanding of radiation and radioactivityradiation and radioactivity
• To provide basic radiation-science To provide basic radiation-science information for use by science teachersinformation for use by science teachers
Health Physics SocietyHealth Physics SocietySpecialists in Radiation ProtectionSpecialists in Radiation Protection
OutlineOutline• Radiation theory & basicsRadiation theory & basics• Exposure and effectsExposure and effects• Ways to minimize exposureWays to minimize exposure• Beneficial uses in modern societyBeneficial uses in modern society• Resources and additional information Resources and additional information
Why Are Elements Why Are Elements Radioactive?Radioactive?
Unstable nucleus:Unstable nucleus:
• Has excess energy.Has excess energy.
• Wants to go to Wants to go to “ground state.”“ground state.”
• Becomes stable by Becomes stable by emitting ionizing emitting ionizing radiation.radiation.
What does “ionizing” mean?What does “ionizing” mean?
Who Discovered Who Discovered Radioactivity?Radioactivity?
Antoine Henri BecquerelAntoine Henri Becquerel
• Worked with uranium.Worked with uranium.• Noticed phosphorescence Noticed phosphorescence
caused film exposure after caused film exposure after leaving uranium in the leaving uranium in the sun.sun.
• Noticed same thing Noticed same thing happened on cloudy days. happened on cloudy days.
The Electromagnetic SpectrumThe Electromagnetic Spectrum
Figure courtesy of NASA/JPL-CaltechFigure courtesy of NASA/JPL-Caltech
137mBa
Excited Nucleus
Gamma ray
137Ba
Ionizing Radiations Ionizing Radiations
Gamma EmissionGamma Emission
DefinitionsDefinitions• Radioactive decayRadioactive decay is a spontaneous process in which is a spontaneous process in which
nucleons are emitted from or transformed within the nucleons are emitted from or transformed within the nucleus, resulting in a change in the identity of the nucleus, resulting in a change in the identity of the nucleus, and usually accompanied by the emission of nucleus, and usually accompanied by the emission of one or more types of radiation from the nucleus and/or one or more types of radiation from the nucleus and/or atom.atom.
• Half-lifeHalf-life is the time required for half of the atoms of a is the time required for half of the atoms of a radioactive material to decay to another nuclear form.radioactive material to decay to another nuclear form.
Who’s the Famous “Madame” of Who’s the Famous “Madame” of Radiological Fame?Radiological Fame?
Marie CurieMarie Curie• With her husband With her husband
Pierre, discovered Pierre, discovered radium and coined radium and coined the term “radioactive”the term “radioactive”
• First woman to win First woman to win two Nobel Prizestwo Nobel Prizes
Units of RadioactivityUnits of Radioactivity
• The becquerel (Bq) The becquerel (Bq) or or • The curie (Ci)The curie (Ci) 1 Ci = 37,000,000,000 Bq1 Ci = 37,000,000,000 Bq so 1 mCi = 37 MBqso 1 mCi = 37 MBq and 1 µCi = 37 kBqand 1 µCi = 37 kBq
Biological EffectsBiological EffectsMechanisms of InjuryMechanisms of Injury
Ionizing Radiation
Cell Death
Cell Damage
Repair Transformation
Radiation DoseRadiation Dose Dose or radiation dose is a generic term for a measure of radiation exposure. In radiation protection, dose is expressed in millirem.
X-Ray Machine Image
(film)Subject is not radioactive but has been exposed to a radiation dose (single chest x ray = 5-10 mrem).
After
External Dose
ContaminationContamination Contamination is the presence of a radioactive Contamination is the presence of a radioactive
material in any place where it is not desired, material in any place where it is not desired, and especially in any place where and especially in any place where
its presence could be harmful.its presence could be harmful.
Remember – We get approximately 300 mrem per year from natural background Remember – We get approximately 300 mrem per year from natural background exposure.exposure.
Minimizing Exposure - TimeMinimizing Exposure - Time
• Minimize the Minimize the amount of time amount of time spent near spent near sources of sources of radiation.radiation.
Minimize Exposure by Minimize Exposure by Maximizing DistanceMaximizing Distance
As the distance from a radioactive source doubles, the exposure rate
decreases by a factor of four.
Minimizing Exposure By Minimizing Exposure By Using ShieldingUsing Shielding
Lead blanket Lead blanket shielding around shielding around letdown radiation letdown radiation monitorsmonitors
Surry Power Station
Loss of Life ExpectancyLoss of Life ExpectancyActivity or Behavior LLE (DAYS)__________________
Recreational swimming 40 Being 15 percent overweight 900 Smoking 20 cigarettes per day 1,600 Using pesticides at home 12 Being exposed to radon in a home 35
Living within 10 miles of a nuclear power plant 0.4 Riding a bicycle 6 Driving a car 200
Skydiving 25 Consuming alcohol (U.S. average) 230
Medicine and ResearchMedicine and Research
• Colleges
• Doctors’ Offices
• Hospitals
• Pharmaceutical
• Research and Development
Research: As a “Tracer”Research: As a “Tracer”
• Radioactivity is an excellent Radioactivity is an excellent tool!tool!
• Detectable in minute quantitiesDetectable in minute quantities
(like finding one grain of sand (like finding one grain of sand on a small beach containing on a small beach containing 6,000,000,000 granules)6,000,000,000 granules)
Power GenerationPower Generation
Nuclear power Nuclear power supplies 20 percent supplies 20 percent of energy in the of energy in the United States. United States. There are 104 There are 104 nuclear power nuclear power plants in the United plants in the United States.States. Photo by Karen Sheehan
Space ExplorationSpace Exploration
The fuel in:The fuel in:• SatellitesSatellites• Jupiter ProbeJupiter Probe• OthersOthers
Jupiter Probe
Who Discovered X Rays?Who Discovered X Rays?Wilhelm Conrad Wilhelm Conrad
RoentgenRoentgen
Roentgen worked with a Crookes tube to study cathode rays.
How X Rays WorkHow X Rays Work
X Rays (continued)X Rays (continued)
Other Types of X-Ray MachinesOther Types of X-Ray Machines