Abstract:
:The use of calibrated tissue-equivalent (TE) ionisation chambers is commonly considered to be the most practical method for total absorbed dose determinations in mixed neutron-photon fields for biomedical applications. The total absorbed dose can be derived from the charge produced within the cavity of an ionisation chamber employing a number of physical parameters. To arrive at the charge produced in the cavity several correction factors have to be introduced which are related to the operational characteristics of the chambers. Information on the operational characteristics of four TE ionisation chambers is presented in relation to ion collection, density and composition of gas in the cavity, wall thickness and effective point of measurement. In addition, some recent results from an ionisation chamber operated at high gas pressures (up to 8 MPa(80 bar)) are presented. The total absorbed doses derived from TE ionisation chambers show agreement within the uncertainty limits with results from other independent dosimetry methods, i.e., differential fluence measurements and a TE calorimeter. Conscientious experimentation and a common data base can provide dosimetry results with TE ionisation chambers with variations of less than +/- 2%.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Zoetelief J,Broerse JJdoi
10.1088/0031-9155/28/5/005subject
Has Abstractpub_date
1983-05-01 00:00:00pages
503-20issue
5eissn
0031-9155issn
1361-6560journal_volume
28pub_type
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