Parallel-plate ionization chamber response in cobalt-60 irradiated transition zones
The authors study the acceptance of a Capintec parallel-plate ionization chamber. The Capintec chamber is used for dose measurements in a lead and polystyrene slab phantom irradiated with cobalt-60 ..gamma.. rays. The authors define an enhancement ratio to quantify the dose measurements. The enhancement ratio equals the ratio of dose measured with the lead slab present to dose measured under equilibrium conditions in polystyrene at equal primary beam attenuation. The measured enhancement ratio at the exit side of the lead/polystyrene interface is 25% lower than the Monte Carlo predicted enhancement ratio. The authors propose that geometric acceptance limitations of the Capintec chamber to large-angle, low-energy electrons are the cause for this difference. A Monte Carlo simulation of the Capintec chamber acceptance confirms the hypothesis.
- Research Organization:
- University of Rochester Cancer Center, Department of Radiation Oncology, Rochester, New York 14642
- OSTI ID:
- 5342252
- Journal Information:
- Med. Phys.; (United States), Journal Name: Med. Phys.; (United States) Vol. 15:2; ISSN MPHYA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
655003* -- Medical Physics-- Dosimetry
ALUMINIUM
COPPER
DOSIMETRY
ELEMENTS
GAMMA DOSIMETRY
INTERFACES
IONIZATION CHAMBERS
LEAD
MATERIALS
MEASURING INSTRUMENTS
METALS
MOCKUP
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PHANTOMS
PLASTICS
POLYMERS
POLYOLEFINS
POLYSTYRENE
POLYVINYLS
RADIATION DETECTORS
RADIATION DOSE DISTRIBUTIONS
STRUCTURAL MODELS
SYNTHETIC MATERIALS
TIN
TRANSITION ELEMENTS