Radioactivity exposure: roentgen

Amounts of radioactivity are designated in terms of rads, roentgens, curies, disintegrations per unit time (minute), or counts per unit time (minute). The relationships between these various unit designations are summarized in Table 3-3. The first two units are rarely used except for measuring human exposure to ionizing radiation. It is worthy of emphasis... 

Milliroentgen One one-thousandth of a roentgen. A roentgen is a unit of radioactive dose, mppcf Millions of particles per cubic foot of air, a conunon unit of exposure concentration for mineral dusts. 

Roentgen A unit of radioactive dose or exposure (abbreviated R). A roentgen is that amount of x- or gamma radiation that will prodnce one electrostatic unit of charge, of either sign, in one cubic centimeter of dry air at standard temperature and pressure. It is equivalent to 2.58 X ICf C7kg in air. 

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