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A parallel plate chamber for calibration of 192 Ir LDR and HDR sources
Author(s) -
Das K. R.,
Kenny M. B.
Publication year - 1999
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 - 10.1118/1.598762
Subject(s) - electrometer , ionization chamber , calibration , brachytherapy , dosimetry , quality assurance , optics , materials science , ionization , sensitivity (control systems) , linear particle accelerator , physics , nuclear medicine , beam (structure) , engineering , electronic engineering , ion , radiation therapy , medicine , operations management , external quality assessment , quantum mechanics
A good program of quality assurance requires the user to check the calibration of brachytherapy sources. Conventional well‐type ionization chambers have restrictions on the length of the source which can be used due to the variation in the relative ionization with distance from the position of maximum sensitivity. We have fabricated a parallel plate chamber, which can be used for both LDR and HDR sources of192 Ir placed centrally inside. The electrodes are made from printed circuit boards. Sources of lengths up to 15 cm can be calibrated with this chamber. It has a good linear response and stability. It costs little and can be used with any electrometer. The chamber, which has a volume of about 40 cm 3 , has a response of 820 nC min − 1percGy m 2 h− 1.