Study for Multi Channel Radiation Detector Using of Microfilm and Carbon Electrode / 의학물리

ABSTRACT

We have designed the multi channel detector for the quality assurance of clinical photon beams. The detector was composed of solid phantom inserted by six plane-parallel ionization chambers at different depth. The chamber as a mini plane parallel chamber was made of carbon coated microfilms. In this study the electrical characteristics of the six chambers in the solid phantom were evaluated using 6 MV photon beam. The leakage currents were less than 0.5 pA, reproducibility was less than 0.5%, linearity was less than 0.5%, and dose rate effect was less than 0.7%. In addition the effect of dose variation from other chambers was estimated to maximum 0.8% approximately. The developed detector can be used for quality determination in output dosimetry or measurement of percentage depth dose approximately for clinical photon beam.