Measurement and calculation of neutron leakage from a medical electron accelerator
The leakage neutron spectra and dose equivalent were systematically measured in the irradiation field, treatment room, maze, and outside the shielding door at the microtron medical electron accelerator facility of the National Cancer Center, Tokyo. For these measurements, we used two types of multimoderator neutron spectrometers (Bonner spheres containing indium activation detectors and /sup 3/He detector), an aluminum activation detector, and a commercially available neutron rem counter. The measured results were compared with the combined calculation of the one-dimensional ANISN and two-dimensional DOT3.5 discrete ordinates transport codes. The calculation was performed by using a measured source spectrum in the irradiation field and by computer modeling of the maze entrance. The calculation indicated good agreement in spectral shape and agreement with experiment within a factor of 2 in absolute dose-equivalent values. This transport calculation was systematically repeated for different geometrical and material parameters, and simple analytical formulas and their parameters applicable for shielding design of a medical electron accelerator facility were obtained in general form.
- Research Organization:
- Institute for Nuclear Study, University of Tokyo, 3-2-1, Midori-cho, Tanashi, Tokyo 188 Japan
- OSTI ID:
- 5871208
- Journal Information:
- Med. Phys.; (United States), Journal Name: Med. Phys.; (United States) Vol. 13:3; ISSN MPHYA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACCELERATORS
DESIGN
DOSE EQUIVALENTS
DOSES
IRRADIATION
MEDICINE
NEUTRON LEAKAGE
NEUTRON SPECTROSCOPY
NUCLEAR MEDICINE
RADIATION DOSES
RADIATION PROTECTION
RADIOLOGY
RADIOTHERAPY
SHIELDING
SPECTROSCOPY
THERAPY