The problem of validating estimates of absorbed dose due to photon energy deposition is examined. The computational approaches used for the estimation of the photon energy deposition is examined. The limited data for validation of these approaches is discussed and suggestions made as to how better validation information might be obtained. (ACR)
Data are tabulated on the radiation dose equivalent per microcurie-day for source and target organs of a human adult for 100 radionuclides. These are listed at the end of the volume. Included are several radionuclides where the parent has a daughter radionuclide of physical half-life less than five minutes. In such cases separate S tables are given for the parent and for the daughter as well as a composite table which contains S values for the parent plus S values for the daughter weighted according to the percent decay via the daughter. (CH)
Many inherent advantages are apparent in the use of large planar Ge detectors for the detection, identification, and quantitative assessment of internally deposited actinide nuclides ($sup 238$Pu, $sup 239$Pu, $sup 240$Pu, $sup 242$Pu, $sup 241$Am, $sup 244$Cm, $sup 246$Cm, and $sup 250$Cf). The superior energy resolution in contrast to Phoswich type scintillation detectors, permits isotopic identifications to be made and reduces ambiguities introduced by natural and human background effects. Preliminary studies indicate that a 10 cm$sup 2$ x 1.2 cm Ge detector is comparable in detection sensitivity to that of one 125 cm$sup 2$ Phoswich detector. Some preliminary considerations and evaluations, photon transport studies based on Monte Carlo modeling and measurements of absolute L-series X-ray yields in the decay of several actinide nuclides, are presented. (auth)
Low attack rates (0.1 to 0.5 mpy) were displayed by coupon specimens of type 347 stainless steel, titanium RC-55, and Zircaloy-2 which were exposed for 2877.5 hr in an oxygenated slurry of Th--8% U oxide, 116.5 hr in water, 6.9 hr in 5% HNO/sub 3/, and 4.3 hr in 3% triscdium phosphate during mns SM-6 through SM-9 in the slurry blanket mockup. The leading coupon of type 347 stainless steel showed a slightly higher rate than the other stainless steel ccupons due to entrance effects. Specimens of SA-212-B carbon steel displayed average attack rates of 2.9 mpy. (auth)
Estimating absorbed doses to children from external and internal radiation sources has become important to the nuclear industry and pediatric nuclear medicine. The Medical Physics and Internal Dosimetry Section at ORNL has recently completed the design of mathematical representations of children of ages newborn, 1 year, and 5 years old. These mathematical representations will be referred to as pediatric phantoms. Using these phantoms, relevant energy deposition data have been developed which establish a meaningful model for use in estimating radiation dose to children. (auth)
The purpose of this study was to determine, by theoretical calculation and experimental measurement, the absorbed dose distributions in two heterogeneous phantoms representing one-year- and five-year-old children from typical radiographic examinations for those ages. Theoretical work included the modification of an existing internal dose code which uses Monte Carlo methods to determine doses within the Snyder-Fisher mathematical phantom. A Ge(Li) detector and a pinhole collimator were used to measure x-ray spectra which served as input to the modified Monte Carlo codes which were used to calculate organ doses in children. The calculated and measured tissue-air values were compared for a number of organs. For most organs, the results of the calculated absorbed doses agreed with the measured absorbed doses within twice the coefficient of variation of the calculated value. The absorbed dose to specific organs for several selected radiological examinations are given for one-year-old, five-year-old, and adult phantoms.
Date: April 1, 1978
Creator: Chen, W. L.; Poston, J. W. & Warner, G. G.
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