PD-0814 Quantification and correction of volume effect perturbations from detectors in small proton fields. (May 2022) - Kretschmer, J.; Brodbek, L.; Behrends, C.; Kugel, F.; Koska, B.; Bäumer, C.; Wulff, J.; Timmermann, B.; Looe, H.K.; Poppe, B.