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A review of the discrepancy between the in‐air and in‐water calibration of cobalt‐60 machines
Author(s) -
Berkley L. W.,
Gag W. F.,
Hanson W. F.,
Weaver K. A.,
Shalek R. J.
Publication year - 1980
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 - 10.1118/1.594751
Subject(s) - calibration , backscatter (email) , displacement (psychology) , ionization , physics , ionization chamber , data set , optics , materials science , nuclear medicine , remote sensing , geology , mathematics , statistics , computer science , medicine , telecommunications , ion , quantum mechanics , wireless , psychotherapist , psychology
Causes for the discrepancy noted by Grant et al . between the in‐water and in‐air calibration of 60 Co are discussed. Data are presented from measurements with a set of ionization chambers with thimbles of 0.5, 1.0, and 1.5 cm outside radii. These data include measurements of percentage depth dose, backscatter factors, and displacement factors. The results show that the discrepancy noted by Grant et al . is caused by a combination of small errors both in depth dose data and in the displacement factor incorporated into C λ .