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Anisotropy measurements of a high dose rate Ir‐192 source in air and in polystyrene
Author(s) -
MullerRunkel R.,
Cho S. H.
Publication year - 1994
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.597339
Subject(s) - anisotropy , polystyrene , materials science , dose rate , dosimetry , optics , nuclear medicine , physics , medical physics , medicine , polymer , composite material
Anisotropy measurements in air and in polystyrene were performed for a Nucletron microSelectron 10 Ci Ir‐192 source. TLD rods of similar sensitivity (±3%) were placed on a semicircle around the source center which had been precisely localized by either radiographic means or direct measurement. The anisotropy, expressed as a ratio of TLD reading at a given angle relative to the longitudinal source axis, over the reading at 90°, was measured for distances between 1 and 10 cm from the source center. For both media, a marked anisotropy of the high dose rate source was found. In air, there is no detectable variation in anisotropy with distance up to 10 cm from the source. In polystyrene, however, the anisotropy becomes less pronounced with increasing distance due to scatter. For both media, no difference, within the estimated experimental accuracy of ±5%, was found between three consecutive sources installed by the vendor.