Abstract:
:A calibration of the Fricke dosimeter is a measurement of epsilon G(Fe3+). Although G(Fe3+) is expected to be approximately energy independent for all low-LET radiation, existing data are not adequate to rule out the possibility of changes of a few per cent with beam quality. When a high-precision Fricke dosimeter, which has been calibrated for one particular low-LET beam quality, is used to measure the absorbed dose for another low-LET beam quality, the accuracy of the absorbed dose measurement is limited by the uncertainty in the value of G(Fe3+). The ratio of G(Fe3+) for high-energy x-rays (20 and 30 MV) to G(Fe3+) for 60Co gamma-rays, G(Fe3+)MV(Co), was measured to be 1.007(+/-0.003) (confidence level of 68%) using two different types of water calorimeter, a stirred-water calorimeter (20 MV) and a sealed-water calorimeter (20, 30 MV). This value is consistent with our calculations based on the LET dependence of G(primary products) and, as well, with published measurements and theoretical treatments of G(Fe3+).
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Klassen NV,Shortt KR,Seuntjens J,Ross CKdoi
10.1088/0031-9155/44/7/303subject
Has Abstractpub_date
1999-07-01 00:00:00pages
1609-24issue
7eissn
0031-9155issn
1361-6560journal_volume
44pub_type
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