Units ionizing radiation

Absorbed Dose, Radiation—The mean energy imparted to the irradiated medium, per unit mass, by ionizing radiation. Units rad (rad), gray (Gy). 

Absorbed Dose—The energy imparted to matter by ionizing radiation per unit mass of irradiated material at the place of interest. The unit of absorbed dose is the rad. One rad equals 100 ergs per gram. In SI units, the absorbed dose is the gray which is 1 J/kg (see Rad). 

Specific Ionization—Number of ion pairs per unit length of path of ionizing radiation in a medium e.g., per centimeter of air or per micrometer of tissue. 

Rep—Roentgen equivalent, physical A former unit of ionizing radiation equivalent to the dosage of 93 ergs absorbed per gram of tissue (93 erg/gm=0.93 rad). 

Roentgen (R)—A unit of exposure (in air) to ionizing radiation. It is the amount of x or gamma rays required to produce ions carrying 1 electrostatic unit of electrical charge in 1 cubic centimeter of dry air under standard conditions. Named after William Roentgen, a German scientist who discovered x rays in 1895. 

UNSCEAR. 1977. United Nations Scientific Committee on the Effects of Atomic Radiation. Sources and effects of ionizing radiation. New York United Nations. 

Since icosahedral carboranes are generally viewed as 3D energy sinks as well as polymer building blocks, the thermal and radiation stability that these units impart on the base rubbery material needs to be explored. While the thermal stability of these materials has been studied and reported by a number of workers, there is little reported work on the stability of these materials to ionizing radiation. A brief account of our work within this area is detailed below. 

United Nations Scientific Committee on the Effect of Atomic Radiation, Ionizing Radiation Sources and Biological Effects, 1982 Report to the General Assembly (1982). 

Unscear, Ionizing radiation sources and biological effects, Report to the General Assembly, United Nations, New York (1982)... 

A variety of units have been used for the assessment of exposures to ionizing radiation. The current international standard terminology is shown in Table 32.3. This chapter uses the new terminology exclusively this frequently necessitated data transformation of units from early published accounts into the currently accepted international terminology. 

Figure 32.6 Chernobyl air plume behavior and reported initial arrival times of detectable radioactivity. Plume A originated from Chernobyl on April 26, 1986 Plume B on April 27-28 and Plume C on April 29-30. The numbers indicate initial arrival times 1, April 26 2, April 27 3, April 28 4, April 29 5, April 30 6, May 1 7, May 2 and 8, May 3. (From United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). 1988. Sources, Effects and Risks of Ionizing Radiation. United Nations, New York. 647 pp.)... 

Data from United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). 1988. Sources, Effects and Risks of Ionizing Radiation. United Nations, New York. 647 pp. Aarkrog, A. 1990. Environmental radiation and radiation releases. Inter. Jour. Radiation Biol. 57 619-631. 

Anti-coincidence units are used to reduce the effects of external interferences. The detector is surrounded by a second guard detector, so that ionizing radiation from outside (e.g. cosmic rays) must active the outer detector before penetrating to the inner. A sample placed close to, or inside, the inner detector will activate that only. The anti-coincidence unit is arranged to accept only the latter noncoincident pulses from the measuring detector. 

Absorbed dose Energy imparted to matter by ionizing radiation per unit mass of irradiated material at the place of interest in that material expressed in rad units. 

Unit for the dose absorbed from ionizing radiation. One rad equals 100 ergs of radiation absorbed per gram of tissue. One gray equals 100 rad. 2. Abbreviation for radian. 

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