The determination of correction factors for free-air ionization chamber calculation using monte carlo method

Abstract

Abstract A free-air ionization chamber is used as the primary standard instrument for absolute measurement of air kerma for of X-ray beams. The evaluation of correction factors is a key importance for establishing the standard. Photon-scattering, and diaphragm transmission and scattering were taken into the accounts to reduce some photon phenomena. On the other hand, electron-loss factor which scatter from an electrode were used for electron compensates. In this research, Correction factors were calculated for each mono-energetic photon from 2 to 60 keV for low energy x-rays and 10 to 320 keV for medium energy x-rays by EGS5 code. The calculated corrections from a mono-energetic photon of W/Mo mammography x-rays were compared between effective energy and spectrum method. There is no significant difference between two methods.