The performance of the INER improved free-air ionization chamber in the comparison of air kerma calibration coefficients for medium-energy X-rays

This paper describes modifications to an original design, correction factors and uncertainty evaluations for an improved free-air ionization chamber constructed at the Institute of Nuclear Energy Research (INER, Taiwan). In addition, a comparison of secondary standard air kerma calibration coefficients for 100-250kV medium-energy X-rays was performed to verify the experimental accuracy and measurement consistency of the improved chamber. The comparison results showed a satisfactory agreement in the measurements which were within the combined expanded uncertainties (k=2).