The properties of gamma radiation.

Gamma radiation is very high-energy ionizing radiation. Gamma photons have about 10,000 times as much energy as the photons in the visible range of the electromagnetic spectrum.

Gamma photons have no mass and no electrical charge--they are pure electromagnetic energy.

Because of their high energy, gamma photons travel at the speed of light and can cover hundreds to thousands of meters in air before spending their energy. They can pass through many kinds of materials, including human tissue. Very dense materials, such as lead, are commonly used as shielding to slow or stop gamma photons.

Their wave lengths are so short that they must be measured in nanometers, billionths of a meter. They range from 3/100ths to 3/1,000ths of a nanometer.

Gamma rays and x-rays, like visible, infrared, and ultraviolet light, are part of the electromagnetic spectrum. While gamma rays and x-rays pose the same kind of hazard, they differ in their origin. Gamma rays originate in the nucleus. X-rays originate in the electron fields surrounding the nucleus or are machine-produced.

Health Effects of Gamma Radiation

Because of the gamma ray's penetrating power and ability to travel great distances, it is considered the primary hazard to the general population during most radiological emergencies. In fact, when the term "radiation sickness" is used to describe the effects of large exposures in short time periods, the most severe damage almost certainly results from gamma radiation.

Protecting People from Gamma Radiation

You need specialized equipment to detect gamma radiation. You cannot see, or feel radiation hitting your body. However, you should be familiar with radiation warning symbols. You can protect yourself by avoiding devices with this symbol, and not entering areas where the symbol is posted.

 In February of 2007, the United Nations introduced a new symbol to help reduce accidental exposure to large radioactive sources. The new icon is aimed at alerting anyone, anywhere to the potential dangers of being close to a large source of ionizing radiation.