A detailed study on the neutron contamination for a 10 MeV medical electron accelerator

Neutron contamination from a 10 MeV medical electron accelerator was investigated by applying both calculations and measurements. The FLUKA Monte Carlo code was used for calculating neutron production and transport with an emphasis on the detailed modeling of the accelerator head and the treatment room. It was found that neutrons were produced dominantly from both the primary and the secondary collimators by 10 MV X-rays. Neutrons produced from upper gantry components will be attenuated to some extent by the lower collimators. The FLUKA-calculated results for detector positions located along the maze of the treatment room were compared with measurements of He-3 proportional counters and conventional bubble detectors, and also compared with the estimations predicted by the Kersey method.