A peer-reviewed journal published by K. N. Toosi University of Technology

Document Type : Research Article


Department of Physics, K.N. Toosi University of Technology, P.O. Box 15875-4416, Tehran, Iran


‎Due to the selectively treating tumors and largely sparing normal neighboring cells‎, ‎Boron Neutron Capture Therapy (BNCT) continues to be of special significance and interest for wide groups of researchers‎. One of the most important challenges in this context is to design an optimized beam based on an appropriate neutron source‎. ‎The‎ ‎recent studies‎, ‎focused on investigating neutron sources as alternatives‎ ‎for nuclear reactors‎, ‎revealed the high potential of electron linac-based photoneutron sources to improve the efficiency of this‎ treatment method‎. ‎Inquiring about the efficiency of a layered model of beam shaping assembly (BSA) for photoneutron sources to be used in BNCT of deep tumors is the main subject of this simulation study‎. This model‎, ‎unlike the traditional BSA in which the reflector surrounds the whole moderator‎, includes many concentric cylinders of reflectors and moderators‎. ‎The MCNPX simulations for various primary energies show that the layered model results in more appropriate beam characteristics compared with that of the common geometry‎. ‎Moreover‎, ‎the parameters governing the beam properties such as the thickness of the layers‎, ‎moderator/reflector and collimator lengths‎, ‎and the thickness of the surrounding reflector have been investigated‎. ‎The results are encouraging and‎ ‎offer new ways to accomplish more researches in‎ ‎studies on the BNCT technique‎.


• Photoneutron sources of 25 MeV and 30 MeV have been considered for BNCT of deep tumors.
• A layered reflector/moderator BSA model has been designed to be used for electron linac photoneutron sources.
• The IAEA criteria have been considered to optimize the BSA cells.
• The results show considerable effect of the layered model on improving the in-air parameters for photoneutron sources.


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