The research of backscattering effect on the installed area monitors and/or warning devices for gamma radiation

Abstract: This paper reports an experimental investigation into the backscatter effects on gamma radiation monitors. The study addresses deviations in measurement readings observed in wall-mounted monitors compared to free-air devices due to backscatter phenomena. Reinforced concrete test blocks were employed to simulate operational environments, with measurements conducted using three detector types: a radiation protection level dosimeter with ionization chamber, an air-kerma radiation monitor with counter tube, and a radiation detector with NaI(Tl) scintillator. Analysis of backscatter factors at varying distances and orientations revealed that: (1) backscatter factors decreased with increasing source-to-surface distance, and (2) central irradiation generally yielded higher backscatter factors than non-central irradiation. The experimental data provide essential reference for formulating or revising pertinent technical standards.