Bremsstrahlung and Photoneutron Leakage from Steel Shielding Board Impinged by 12-24 MeV Electrons Beams

Many medical linear accelerators generate not only high-energy photons, but also high-energy electrons, and they are no longer equipped with beam stoppers. Therefore, shields might be necessary against bremsstrahlung and photoneutron generated by high-energy electron beams. However, there are few physical studies, and no recommendations are made about shields nowadays. In this report, the leakage doses of bremsstrahlung and photoneutron were calculated by the use of Monte Carlo simulation. To verify the calculated results, the photoneutron leakage dose was measured with a rem counter. The results clearly show that the bremsstrahlung and photoneutron leakage dose generated by electron beams of 24 MeV or below is negligible.