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Module 1 – Radiation Basics

This first RADUCATION module will focus on some radiation basics:

  1. What is an atom?
  2. How does an atom give off (emit) radiation?
  3. What are the three primary types of radiation?
  4. How is radiation used?
  5. How is the use of radiation regulated in Ohio?

1. What is an Atom?

All matter, which is everything that exists, is made up of atoms. Atoms are very, very small and made up of protons and neutrons clustered in a nucleus at the center, surrounded by a cloud of electrons orbiting around the outside. Atoms make up elements, like Oxygen, Hydrogen, and Potassium. The number of protons found in the nucleus determines the element.

An atom may have an electrical charge, just like a battery. The protons in the nucleus have a positive (+) charge and the orbiting electrons have a negative (-) charge. The neutrons in the nucleus have no charge. If the number of protons in an atom equals the number of surrounding electrons, then the amount of positive charge in the atom would equal the amount of negative charge, resulting in an atom with a neutral charge.

In some cases an atom of an element may have more or less neutrons than protons in the nucleus. When the number of protons remains the same, but the number of neutrons is different, we call these isotopes of the same element. Isotopes are generally referred to by the element name and a number, based on the total number of protons and electrons present. To explain this, we will use the element Carbon.

The number of protons in a nucleus determines an element’s atomic number. All atoms of Carbon have six protons in the nucleus, so the atomic number for Carbon is “6”. In the most common form of Carbon, there are also six neutrons. If you add together the number of protons and neutrons, you get the number of the Carbon isotope, which in this case would be Carbon-12. Other isotopes of Carbon will have a different number of neutrons in the nucleus. Another common Carbon isotope, with eight neutrons and six protons, is called Carbon-14, and is a radioactive isotope of this element.  

2. How Does an Atom Give Off (Emit) Radiation?

If an atom is not stable (unstable) it has too much energy to remain in its current form.  All radioactive atoms are unstable, and will give off, or emit, this extra energy through various methods, eventually becoming a stable atom.  When a radioactive atom is giving off energy it is said to be going through radioactive decay.  How long this decay process may take depends on the type of radioactive atom.

The energy given up by the nucleus of a radioactive atom may cause one or more electrons to be “kicked” out of their orbit around an atom.  When this happens there will be a negatively- charged electron floating by itself, and an atom with a positive charge, also called an ion, due to the loss of the electron.  The energy from a radioactive atom that causes the formation of ions is called ionizing radiation.

3. What are the Three Primary Types of Radiation?

Ionizing radiation is generally found in one of three forms – alpha particles, beta particles, or gamma rays.

Alpha particles are made up to 2 neutrons and 2 protons and are essentially a small nucleus with no orbiting electrons and a positive charge. Because alpha particles are fairly large (at least in atomic terms) they will interact with more atoms and use up their energy creating ions over a very short distance (again, in atomic terms). Because of these characteristics, an alpha particle may be stopped by something as thin as a sheet of paper or layer of cloth. 

  A beta particle is really just an electron that is no longer in orbit around a nucleus. It is extremely small and much lighter than an alpha particle. A beta particle typically contains more energy and will travel further than alpha particles through solid materials. Beta particles are usually stopped using sheets of plastic or Lucite.
Gamma radiation is different from alpha and beta because it is not a particle; gamma radiation is a ray of energy, similar to visible or ultraviolet light, but containing much higher energy levels. Depending on their energy level, gamma rays may be stopped by various thicknesses of lead, concrete, or soil. X-rays used in dental and medical procedures are similar to gamma rays and will typically be included with them in future RADUCATION modules.    

4. How is Radiation Used?

Radiation from radioactive materials or radiation-generating equipment (x-rays) is used in a wide range of commercial, medical, and research procedures and processes. 

Commercial and Industrial Uses

Radiation may be easily detected because of the energy that it contains.  This trait makes it useful in measuring thicknesses, volumes, flow rates, densities, and contaminant levels.  If a radiation source and an appropriate detector are set up together, anything that passes between the two will cause a change in the amount of radiation received by the detector.  Analyzing this change will allow the user to know if their process is operating properly.

Two common consumer products contain very small quantities of radioactive material used to perform their very useful functions. Many smoke detectors contain the isotope Americium-241 in the detection portion of the device. Another widespread commercial use of radiation is in building exit signs which contain radioactive Hydrogen-3, also called tritium. The fluorescent properties of tritium allow the exit signs to remain illuminated during a power outage.

Radiation in very large quantities is used as a sterilization method. The energy released by the gamma radiation as it passes through the product being sterilized is what “performs” the sterilization. The radioactive material used to produce the gamma radiation never comes in contact with the materials being sterilized. This can be a useful alternative when chemical sterilization may actually contaminate the product being treated, such as cosmetics, contact lens solutions, and many medical supplies. Radiation is also routinely used to sterilize bulk quantities of spices and some grains. 

Medical Uses
Radiology is the common term for the use of radiation in the diagnosis and treatment of disease. Radiology not only refers to the medical use of x-ray devices, but also to the practice of nuclear medicine, which uses various radioactive materials and procedures for patients with such diverse problems as cardiac disease, thyroid disorders, respiratory problems, and some forms of cancer. Some laboratory tests use radioactive materials in the analysis of blood and various other body fluids and tissues.

Radiation use has increased significantly in the area of research. Radioactive materials are used in the development of many new products, including fertilizers, pesticides, and chemical products. A common use in research is carbon dating, which allows researchers to determine the age of an item - such as mummified remains or a prehistoric skeleton - by measuring the amount of radioactive Carbon-14 present in the sample. Measuring the amount radioactive material in soil and rocks allows geologists to determine whether valuable minerals might be present.

5. How is Radiation Use Regulated in Ohio?

The Ohio Department of Health (ODH) is the agency responsible for oversight of the many medical, academic, industrial and research uses of radioactive materials and radiation-generating equipment in Ohio.  This is an important part of our mission:

"To Protect and Improve the Health of All Ohioans by Preventing Disease, Promoting Good Health and Assuring Access to Quality Health Care”

The Bureau of Environmental Health and Radiation Protection (BEHRP) supports the ODH mission through the regulation of the radioactive materials and radiation-generating equipment used in Ohio. BEHRP program staff work to ensure that the possession, use, handling, storage and disposal of these beneficial materials and equipment are accomplished in a safe and secure manner that will protect the health of all Ohioans.   

Radioactive materials oversight was granted to Ohio as an Agreement State in accordance with the Atomic Energy Act provision allowing such arrangements between the U.S. Nuclear Regulatory Commission and the states.  Radioactive material use is regulated in accordance with rules adopted under Chapter 3748 of the Ohio Revised Code (ORC).

Radiation-generating (x-ray) equipment is also regulated in accordance with rules adopted under ORC Chapter 3748, and through contractual agreements with the U.S. Food and Drug Administration.

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If you would like more information on the topics covered in this RADUCATION module, these links may be helpful:

The Ohio State University Agriculture Extension Service:

Idaho State University, Radiation Information Network:

U.S. Environmental Protection Agency, Radiation Protection:

University of Michigan Health Physics Website:

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If you have questions about any of the information in this module, or want to suggest a topic for a future module, please send your request to:  and put “RADUCATION” in the subject header.

Mailing Address:
Ohio Department of Health
Bureau of Environmental Health and Radiation Protection
Radiation Protection Programs 
246 N. High St.
Columbus, OH 43215

Telephone: (614) 644-2727
Fax: (614) 466-0381

Last Updated: 12/03/2015