Abstract:
:A simple and fast, but sensitive TLD method for the measurement of energy and homogeneity of therapeutically used electron beams has been developed and tested. This method is based on the fact that when small thicknesses of high-Z absorbers such as lead are interposed in the high-energy electron beams, the transmitted radiation increases with the energy of the electron beams. Consequently, the ratio of readouts of TLDS held on the two sides of a lead plate varied sharply (by factor of 70) with a change in energy of the electron beam from 5 MeV to 18 MeV, offering a very sensitive method for the measurement of the energy of electron beams. By using the ratio of TL readouts of two types of TLD ribbon with widely different sensitivities, LiF TLD-700 ribbons on the upstream side and highly sensitive CaF2:Dy TLD-200 ribbons on the downstream side, an electron energy discrimination of better than +/- 0.1 MeV could be achieved. The homogeneity of the electron beam energy and the absorbed dose was measured by using a jig in which the TLDS were held in the desired array on both sides of a 4 mm thick lead plate. The method takes minimal beam time and makes it possible to carry out measurements for the audit of the quality of electron beams as well as for intercomparison of beams by mail.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Pradhan AS,Quast U,Sharma PKdoi
10.1088/0031-9155/39/9/005subject
Has Abstractpub_date
1994-09-01 00:00:00pages
1367-76issue
9eissn
0031-9155issn
1361-6560journal_volume
39pub_type
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