Aerosols produced by X-rays☆

Abstract Small proportions of organic vapors in air produce aerosols under the influence of X-rays. The particulates are generally spherical in shape and less than a micron in diameter. Those formed from acetylene and benzene vapor appear yellow and brown, respectively. They are essentially nonvolatile at room temperature and are very stable even when exposed to the high vacuum of an electron microscope. However, a substantial size reduction was attained by several hours of heating at 250°C under atmospheric pressure. The size and quantity of the particulates formed under Xirradiation depend on the organic vapor, its concentration, the humidity of the air, the intensity of the X-rays, irradiation time, and aging time after exposure. The growth and formation of particulates do not stop immediately after exposure ceases. Infrared spectrum analysis provides information on the chemical structure of the particulates.