EMR - Properties

EMR - 2 Classes

Classes of EMR	Examples	Description
Non-Ionizing Radiation	visible light infrared microwaves radio waves	individual photons do not individually have enough energy to ionize atoms or molecules or break chemical bonds effects of these radiations on chemical systems and living tissue are caused primarily by heating effects from the combined energy transfer of many photons
Ionizing Radiation	ultraviolet X-rays gamma rays	individual photons of such high frequency have enough energy to ionize molecules or break chemical bonds can also induce heating

Gamma radiation and X-rays are highly penetrating electromagnetic radiation. Some characteristics of these radiations are:

does not consist of any particles, instead consisting of a photon of energy being emitted from an unstable nucleus
Gamma radiation or X-rays are able to travel many feet in the air and many inches in human tissue. They readily penetrate most materials and are sometimes called “penetrating” radiation.
X-rays are like gamma rays. X-rays, too, are penetrating radiation. Sealed radioactive sources and machines that emit gamma radiation and x-rays respectively constitute mainly an external hazard to humans.
Gamma radiation and x-rays are electromagnetic radiation like visible light, radio waves, and ultraviolet light. These electromagnetic radiations differ only in the amount of energy they have. Gamma rays and x-rays are the most energetic of these.
Dense materials are needed for shielding from gamma radiation. Clothing provides little shielding from penetrating radiation but will prevent contamination of the skin by gamma-emitting radioactive materials.
Gamma radiation is easily detected by survey meters with a sodium iodide detector probe.
Gamma radiation and/or characteristic x-rays frequently accompany the emission of alpha and beta radiation during radioactive decay.

Examples of some gamma emitters: iodine-131, cesium-137, cobalt-60, radium-226, and technetium-99m.