Presentation on theme: "Radiation “Awareness” Objectives To increase public understanding of radiation and radioactivityTo increase public understanding of radiation and radioactivity."— Presentation transcript:
Radiation “Awareness” Objectives To increase public understanding of radiation and radioactivityTo increase public understanding of radiation and radioactivity To provide basic radiation-science information for use by science teachersTo provide basic radiation-science information for use by science teachers Health Physics Society Specialists in Radiation Protection
Outline 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 informationResources and additional information
Why Are Elements Radioactive? Unstable nucleus: Has excess energy.Has excess energy. Wants to go to “ground state.”Wants to go to “ground state.” Becomes stable by emitting ionizing radiation.Becomes stable by emitting ionizing radiation. What does “ionizing” mean?
Who Discovered Radioactivity? Antoine Henri Becquerel Antoine Henri Becquerel Worked with uranium.Worked with uranium. Noticed phosphorescence caused film exposure after leaving uranium in the sun.Noticed phosphorescence caused film exposure after leaving uranium in the sun. Noticed same thing happened on cloudy days.Noticed same thing happened on cloudy days.
Ionizing Radiations Beta Decay 3H3H 3 He Ion Beta particle Anti Neutrino N P N e e N PP
The Electromagnetic Spectrum Figure courtesy of NASA/JPL-Caltech
137m Ba Excited Nucleus Gamma ray 137 Ba Ionizing Radiations Gamma Emission
Definitions Radioactive decay is a spontaneous process in which nucleons are emitted from or transformed within the nucleus, resulting in a change in the identity of the nucleus, and usually accompanied by the emission of one or more types of radiation from the nucleus and/or atom.Radioactive decay is a spontaneous process in which nucleons are emitted from or transformed within the nucleus, resulting in a change in the identity of the nucleus, and usually accompanied by the emission of one or more types of radiation from the nucleus and/or atom. Half-life is the time required for half of the atoms of a radioactive material to decay to another nuclear form.Half-life is the time required for half of the atoms of a radioactive material to decay to another nuclear form.
Who’s the Famous “Madame” of Radiological Fame? Marie Curie With her husband Pierre, discovered radium and coined the term “radioactive”With her husband Pierre, discovered radium and coined the term “radioactive” First woman to win two Nobel PrizesFirst woman to win two Nobel Prizes
Units of Radioactivity The becquerel (Bq)The becquerel (Bq) or or The curie (Ci)The curie (Ci) 1 Ci = 37,000,000,000 Bq 1 Ci = 37,000,000,000 Bq so 1 mCi = 37 MBq so 1 mCi = 37 MBq and 1 µCi = 37 kBq and 1 µCi = 37 kBq
Approximate Radioactivity in Assorted Items Item or Process mCi MBq Smoke Detector 0.001 0.037Smoke Detector 0.001 0.037 Biomedical Lab Experiment 0.5 18.5Biomedical Lab Experiment 0.5 18.5 Nuclear Medicine Dose 10 370Nuclear Medicine Dose 10 370 Industrial Radiography Source 40,000 1,480,000Industrial Radiography Source 40,000 1,480,000
Biological Effects Mechanisms of Injury Ionizing Radiation Cell Death Cell Damage Repair Transformation
Radiation 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
Contamination Contamination is the presence of a radioactive material in any place where it is not desired, Contamination is the presence of a radioactive material in any place where it is not desired, and especially in any place where its presence could be harmful. Yuck!
Radiation Detection Instruments Geiger Counter Liquid Scintillation Counter Photo by Karen Sheehan Photo by Carl Tarantino
Lessons from the Past The Radium Dial Painters Photo by Carmelina Rattrovo from the Playwrights Theatre production of Radium Girls, by D.W. Gregory
Annual Radiation Dose Limits General Public vs. Occupational Established by the Nuclear Regulatory Commission General Public Limit - 100 mrem General Public Limit - 100 mrem Occupational Limit - 5,000 mrem Occupational Limit - 5,000 mrem Remember – We get approximately 300 mrem per year from natural background exposure.
Minimizing Radiation Exposure Basic Concepts Time Time Distance Distance Shielding Shielding
Minimizing Exposure - Time Minimizing Exposure - Time Minimize the amount of time spent near sources of radiation.Minimize the amount of time spent near sources of radiation.
Minimize Exposure by Maximizing Distance As the distance from a radioactive source doubles, the exposure rate decreases by a factor of four.
Minimizing Exposure By Using Shielding Lead blanket shielding around letdown radiation monitors Surry Power Station
Loss of Life Expectancy Activity 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 Research Colleges Doctors’ Offices Hospitals Pharmaceutical Research and Development
Research: As a “Tracer” Radioactivity is an excellent tool!Radioactivity is an excellent tool! Detectable in minute quantitiesDetectable in minute quantities (like finding one grain of sand on a small beach containing 6,000,000,000 granules) (like finding one grain of sand on a small beach containing 6,000,000,000 granules)
Power Generation Nuclear power supplies 20 percent of energy in the United States. There are 104 nuclear power plants in the United States. Photo by Karen Sheehan
Space Exploration The fuel in: The fuel in: SatellitesSatellites Jupiter ProbeJupiter Probe OthersOthers Jupiter Probe
Who Discovered X Rays? Wilhelm Conrad Roentgen Roentgen worked with a Crookes tube to study cathode rays.
Nuclear Medicine Diagnostic Procedures Radioactive injectionRadioactive injection Short half-life radionuclideShort half-life radionuclide Pictures taken with special gamma cameraPictures taken with special gamma camera Many different studies:Many different studies:ThyroidLungCardiac White Blood Cell Photo by Karen Sheehan