Basics of Radiation NC Radiation Protection Section- DENR NC Health Physics Society
ENERGY Energy What is "Radiation"? Travels in Waves High Speed Particles
Basic Types of Radiation Ionizing Ionizes:strips electrons from atoms Non-Ionizing many other modes of interaction
Non-Ionizing Radiation Radiation that has enough energy to move atoms in a molecule around or cause them to vibrate, but not enough energy to remove electrons from the atom.
Ionizing Radiation • Ionization is the process in which a charged portion of a molecule (usually an electron) is given enough energy to break away from the atom. • This process results in the formation of two charged particles or ions: • molecule with a net positive charge • free electron with a negative charge
Alpha Radiation () • Particle released when the nucleus kicks out 2 neutrons and 2 protons • Relatively massive • Relatively slow • Total charge of +2 a Mass number changes by 4 and atomic number changes by 2
b • Beta Radiation () • Particle released when the nucleus changes a neutron into a proton and a beta particle • Relatively small mass • Relatively fast moving • Total charge of -1 P N Atomic Mass Number remains constant
g • Gamma Radiation () • Pure energy. Released from the nucleus when an alpha or a beta is emitted • No mass • Speed of light • No charge NO CHANGE
Courtesy of David C Howell, Radiation Safety Officer-Wake Forest University-Baptist Medical Center
Radioactivity Property of some atoms to spontaneously give off energy as particles or rays Caused by instability in the atom’s nucleus or an excess of energy Radioactive atoms try to achieve stability by throwing off Protons or Neutrons, other particles, or by releasing excess energy in other forms
Stable Radioactive Decay Process
Half-life Time required for the disintegration of one-half of the radioactive atoms that are present in a given amount • Uranium-238 (In soil) • 4.5 Billion years • Potassium-40 (in soil and body) • 1.3 Billion years • Carbon-14 (In all living tissue) • 5730 years • Hydrogen-3 (in all water) • 12 years • Radium-226 (In soil - produces radon) • 1600 years • Radon-222 (in soil and air) • 3.8 days • Polonium-214 (radon progeny that decays in lungs) • 164 microseconds
Radiation Units Dose = Rad/ Gray (Gy) 1Gy = 100 rads Dose Equivalent = Rem/ Sievert (Sv) 1Sv = 100 rem Exposure = Roentgen (R) Examples of Radiation Dose from Medical Radiation Exposures • Chest X-ray: 8 mrem (0.08 mSv) • Head CT scan: 111 mrem (1.11 mSv) • Barium Enema: 406 mrem (4.06 mSv) • Extremity X-ray: 1 mrem (0.01 mSv) Source: NCRP Report 100
Linear No-Threshold Risk Model Risk Dose (in addition to natural background radiation)
Cell Sensitivity Most sensitive cells: Rapidly dividing cells (Small intestines, bone marrow, hair, fetus) Least sensitive cells: Slowly dividing cells (brain, nerves)
Categories of Radiation Effects • Acute Somatic • Immediate effects to the organism receiving the dose • Delayed Somatic • Effects that appear years later to organism receiving the dose • Genetic • Effects that appear in offspring
Symptoms of Radiation Sickness • Nausea and vomiting • Diarrhea • Skin burns (redness, blistering) • Weakness, fatigue, exhaustion, fainting • Dehydration • Inflammation of exposed areas (redness, tenderness, swelling, bleeding) • Hair Loss
Symptoms of Radiation Sickness (cont’) • Ulceration of the oral mucosa • Ulceration of the esophagus, stomach or intestines • Vomiting blood • Bloody stool • Bleeding from the nose, mouth, gums, and rectum • Bruising • Sloughing of skin • Open sores on the skin
Radiation Protection Time Distance Shielding Containment
Sources of Radiation in the USA
Industrial Use • Well logging • Test pipes & welds • Control thickness of sheet products • Cold sterilize plastics, pharmaceuticals, cosmetics, and other heat sensitive products • Security checks (luggage) • Prove authenticity of old paintings • Detect pollution
Food Irradiation • Food treatment comparable to pasteurization • Kills pests/microorganisms without food degradation • Controls sprouting • Does not make the food radioactive • FDA Approved • Must be labeled Good information about food irradiation: http://uw-food-irradiation.engr.wisc.edu/Facts.html
Safety and Security • Smoke detection equipment • Self-powered lighting in exit signs • Lighted aircraft instrumentation • Pharmaceutical detection • Bomb/weapons detection • Scanning and surveillance equipment • Theft deterrent systems
Consumer Products • Television sets accelerate electrons to make the picture on the screen and in the process produce a few low energy x-rays. • Some more products or services: long lasting light bulbs, building materials, and luminous dials, among many others.
Consumer Products • Eliminate dust from computer disks & audio & video tapes • Sterilize baby powder, bandages, cosmetics, hair products, & contact lens solutions • Control thickness of sheet products • Attach a non-stick surface to pans • Brighten porcelain in false teeth
Spacecraft Power Supplies • Small radioactive sources have provided heat and electrical power for space probes for decades • Radioactive power supplies have allowed space craft to explore the outer solar system, too far from the sun for solar panels to be effective
Commercial Nuclear Power Reactors in The United States Map of U.S. Nuclear Regulatory Commission Regions
Diagnostic Uses • Generally low doses • Short-time exposures • X-radiation • Radiographs • Fluoroscopy • CT scan • Nuclear Medicine
Therapeutic Uses • Generally high doses • Short to long time exposures Radiotherapy (Direct radiation beam) Gamma rays Electron beams X-radiation • Brachytherapy • (Radiation from internally deposited radioactivity) • Removable seeds (long half-life) • Permanent seeds (short half-life)
Fallout Radiation • Radioactivity remaining after atmospheric nuclear weapons testing • Less than 0.01 mSv (1 mrem)/yr • Long-lived radionuclides: • Cesium-137: 30 year half-life • Mimics potassium - found in muscle • Strontium-90: 29 year half-life • Mimics calcium - found in bones Leukemia is among the greatest of afflictions that are passed on to the offspring of survivors http://www.serendipity.li/more/atomic.html
U.S. Ecology Facility Richland, WA Envirocare Facility Clive, UT Chem Nuclear Facility Barnwell, S.C. Locations of Operating LLRW Facilities in the U.S.
Thank you for your attention Any Questions?