Vincent J. Giblin, General President 1293 Airport Road Beaver, WV Phone: (304) Fax: (304) Radiation Basics

This material was produced under grant number 46C5- HT16 from the Occupational Safety and Health Administration, U.S. Department of Labor. It does not necessarily reflect the views or policies of the U.S. Department of Labor, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.

Operating Engineers National Hazmat Program B.C. n Greek philosophers thought all the matter in the world was made of tiny unbreakable kernels they called atoms n Nothing was smaller than an atom - it couldn’t be broken into parts

Roentgen’s Discovery n In 1895 German physicist Wilhelm Roentgen accidentally discovered a new form of energy which he named the x- ray n Roentgen produced first x-ray image - his own hand n His work sparked feverish research, especially in Germany

Operating Engineers National Hazmat Program5 The New Understanding n In 1913 several scientists published the theory that an atom is made of u a positively-charged central nucleus u orbited by negatively-charged particles

Bohr Model

World War II n Nazi persecution caused Jewish physicists to leave Germany n The physicists understood that splitting the atom would release tremendous energy n Albert Einstein and others approached President Roosevelt

Operating Engineers National Hazmat Program8 Manhattan Project n US secret project to create atomic weapon n Three sites u Hanford, Washington (plutonium fuel) u Oak Ridge, Tennessee (uranium fuel) u Los Alamos, New Mexico (bomb production)

July 1945

Atomic Structure

Nucleus n Contains positively-charged protons n Non-charged neutrons

Electrons n Orbit nucleus n An atom can have as many electrons as it has protons

How big is an atom? n An atom is the same size compared to a golf ball n As a golf ball is compared to the earth

Operating Engineers National Hazmat Program14 The Search for Stability n An atom is stable based on it’s proton to neutron ratio n If there are too many or too few neutrons or protons, the atom will give off excess energy as u rays u particles n This process is called radioactive decay

Operating Engineers National Hazmat Program15 What is Radiation? n As either particles or rays n Two kinds: ionizing and non- ionizing

Operating Engineers National Hazmat Program16 Fission u Fission is the process by which a large, unstable nucleus splits into two nuclei u It rarely occurs naturally

Fission n When the atom splits, “fission fragments” are released

Operating Engineers National Hazmat Program18 Ionizing Radiation n The energy given off by the nucleus is called ionizing radiation n It is strong enough to detach an electron from an atom u When an atom loses an electron, it has a positive charge and is called an ion u The ion and its lost electron are called an ion pair

Non-Ionizing Radiation n Energy in transit that is too weak to detach an electron from another atom n Examples u Light u Radio and television waves u Microwaves

Operating Engineers National Hazmat Program20 Radioactive Decay n When an atom’s nucleus gives off excess energy, the process is called radioactive decay n Radioactive half-life is the time it takes half the radioactive atoms present to decay

Half-Life n The time it takes half the radioactive atoms present to decay BeforeAfter one half-life

Operating Engineers National Hazmat Program22 Half-Life n The time it takes half the radioactive atoms present to decay BeforeAfter one half-life

TYPES OF IONIZING RADIATION

Alpha Particle n Large mass n Consists of 2 protons and 2 neutrons n Electrical charge of +2 n Range in air 1 to 2 inches +1

Alpha shielding n A sheet of paper n Outer layer of skin

Operating Engineers National Hazmat Program26 Biological Hazard n Alpha radiation is not an external hazard, because it can be stopped so easily n If inhaled or swallowed, the alphas emitted from an alpha emitter, can deposit large amount of energy in a small area of body tissue

Operating Engineers National Hazmat Program27 Sources of Alpha Radiation n Plutonium 238 and 239 n Uranium 238 and 235

Beta Particle - ß n Small mass n Electrical charge of -1 n Emitted from nucleus n Range in air about 10 feet

Beta Shielding n Beta has a limited penetrating ability because of its negative charge n Most beta particles can be shielded by plastic, glass, metal foil, or safety glasses

Operating Engineers National Hazmat Program30 Biological Hazard n If ingested or inhaled, a beta- emitter can be an internal hazard n Externally, beta particles are potentially hazardous to the eyes and skin

Operating Engineers National Hazmat Program31 Beta Sources n Uranium decay products n Decay of some radioactive substances (Tritium) n Products of the fission process

Gamma and X-Rays n An electromagnetic wave or photon, which has no electrical charge n Great penetrating power n Range in air easily several hundred feet

Gamma and X-Ray Shielding n Concrete n Lead n Steel

Neutron n A neutron is ejected from the nucleus n No electrical charge n Range in air easily several hundred feet

Operating Engineers National Hazmat Program35 Neutron Radiation Shielding n Best shielded by material with a high hydrogen content u Water u Plastic

RADIATION MEASUREMENT

Operating Engineers National Hazmat Program37 Roentgen (R) n A unit for measuring exposure n Defined for effect in air only n Applies only to gamma and x-rays n Does not relate radiation to the effect on the human body

Operating Engineers National Hazmat Program38 Roentgen (R) n A unit for measuring exposure n Defined for effect in air only n Applies only to gamma and x-rays n Does not relate radiation to the effect on the human body 1 R = 1000 milliRoentgen (mR)

Operating Engineers National Hazmat Program39 Roentgen Absorbed Dose (rad) n Unit for measuring the absorbed dose in any material n Applies to all types of radiation n Does not take into account differing effects on the human body n 1 rad = 1000 millirad (mrad) 1 rad= 1000 millirad (mrad)

Operating Engineers National Hazmat Program40 Radiation Absorbed Dose (rad) n Unit for measuring the absorbed dose in any material n Applies to all types of radiation n Does not take into account differing effects on the human body n 1 rad = 1000 millirad (mrad) 1 rad= 1000 millirad (mrad)

Operating Engineers National Hazmat Program41 Roentgen Equivalent Man (rem) n Unit for measuring radiation equivalence n Most commonly used unit n Takes into account the energy absorbed (dose) and effect on the body of different types of radiation 1 rem = 1000 millirem (mrem)

Operating Engineers National Hazmat Program42 Roentgen Equivalent Man (rem) n Unit for measuring radiation dose equivalence n Most commonly used unit n Takes into account the energy absorbed (dose) and effect on the body of different types of radiation 1 rem = 1000 millirem (mrem)

This material was produced under grant number 46C5- HT16 from the Occupational Safety and Health Administration, U.S. Department of Labor. It does not necessarily reflect the views or policies of the U.S. Department of Labor, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.

Operating Engineers National Hazmat Program44 END n This publication was made possible by grant numbers 5 U45 ES AND 5 U45 ES from the National Institute of Environmental Health Sciences (NIEHS), NIH. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIEHS, NIH.