Bremsstrahlung and photoneutron production in a steel shield for 15-22-MeV clinical electron beams

Yukio Fujita, Atsushi Myojoyama, Hidetoshi Saitoh

    Research output: Contribution to journalArticlepeer-review

    1 Citation (Scopus)

    Abstract

    The physical data regarding bremsstrahlung and neutrons produced in a steel shield by high-energy electron beams from a medical linear accelerator were investigated. These data are required to allow the accurate prediction of shielding performance for high-energy electron beams and in the design of radiotherapy facilities. A Monte Carlo code was used to develop Monte Carlo beam models for clinical electron beams and to directly simulate bremsstrahlung and secondary neutron production in a steel shield. The effective dose and dose equivalent of bremsstrahlung X rays and secondary neutrons outside a vault were determined using a realistic radiation source. The accuracy of Monte Carlo simulations was validated experimentally by comparing the measured and calculated physical quantities. In validating the Monte Carlo simulation, the measured and calculated values showed reasonable agreement, indicating that bremsstrahlung and photoneutron production and transport were simulated accurately. The bremsstrahlung X-ray dose was the main component of the total dose outside a vault. The secondary neutron dose was 1-20 % of the bremsstrahlung X-ray dose, but the neutron dose was also at a non-negligible level. The calculated neutron dose outside the vault differed from the McGinley's reported data. These results indicate that McGinley's method overestimates the neutron dose beyond the steel shield. The physical data used here will be useful in the accurate estimation of bremsstrahlung X-ray and neutron doses for high-energy electron beams.

    Original languageEnglish
    Pages (from-to)148-159
    Number of pages12
    JournalRadiation protection dosimetry
    Volume163
    Issue number2
    DOIs
    Publication statusPublished - 2014 Mar 20

    ASJC Scopus subject areas

    • Radiation
    • Radiological and Ultrasound Technology
    • Radiology Nuclear Medicine and imaging
    • Public Health, Environmental and Occupational Health

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