Most common garter snakes have a pattern of yellow stripes on a brown or green background, and their average total length (including tail) is about 55 cm (22 in), with a maximum total length of about 137 cm (54 in). The average body mass is 150 g (5.3 oz).
Centigray is a radiation absorbed dose measurement unit. A centigray (cGy) is a derived metric (SI) measurement unit of absorbed radiation dose of ionizing radiation, e.g. X-rays. The SI prefix centi stands for one hunfredths.
According to the United States Nuclear Regulatory Commission (NRC), exposure refers to the amount of radiation, such as X-rays, gamma rays, neutrons, alpha and beta particles, present in the air. Exposure, usually expressed in units of roentgens, is measured by Geiger counters and similar devices. A Geiger counter registers how much the gas it contains gets ionized by incoming particles of radiation, and converts that information into an electronic signal.