Performance of a prototype of an extrapolation minichamber in various radiation beams.
An extrapolation minichamber was developed for measuring doses from weakly penetrating types of radiation. The chamber was tested at the radiotherapeutic dose level in a beam from a (90)Sr+(90)Y check source, in a beam from a plane (90)Sr+(90)Y ophthalmic applicator, and in several reference beams from an X-ray tube. Saturation, ion collection efficiency, stabilization time, extrapolation curves, linearity of chamber response vs. air kerma rate, and dependences of the response on the energy and irradiation angle were characterized. The results are satisfactory; they show that the chamber can be used in the dosimetry of (90)Sr+(90)Y beta particles and low-energy X-ray beams.
Oliveira
M L
ML
Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN), Comissão Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000 São Paulo, SP, Brazil. mercial@cnen.gov.br
Caldas
L V E
LV
D004867:Equipment Design; D019544:Equipment Failure Analysis; D008904:Miniaturization; D010865:Pilot Projects; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity