Reply to comment on 'Lateral response heterogeneity of Bragg peak ionization chambers for narrow-beam photon and proton dosimetry'.

Gomà (2020Phys. Med. Biol.) commented on our paper 'Lateral response heterogeneity of Bragg peak ionization chambers for narrow-beam photon and proton dosimetry' (Kuesset al2017Phys. Med. Biol.629189-206) which describes a method to determine the response pattern of large-area ionization chambers using a collimated x-ray beam. Gomà performed a simple Monte Carlo simulation to investigate the energy transferred by secondary electrons within the detector, deducing that our conclusion, that the chamber has a non-uniform response, is not supported by our results. We appreciate the work performed by Gomà very much and believe that the transport of secondary electrons in the chamber is an important contribution to understand the non-uniformity response of large-area chambers in narrow beams. However, we disagree with the conclusions drawn by Gomà that the radial response is homogenous. His simulation actually demonstrates that the response is non-uniform in an x-ray beam.