Nuclear Physics and Atomic Energy

ядерна ф≥зика та енергетика
Nuclear Physics and Atomic Energy

  ISSN: 1818-331X (Print), 2074-0565 (Online)
  Publisher: Institute for Nuclear Research of the National Academy of Sciences of Ukraine
  Languages: Ukrainian, English, Russian
  Periodicity: 4 times per year

  Open access peer reviewed journal

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Nucl. Phys. At. Energy 2019, volume 20, issue 1, pages 70-75.
Section: Engineering and Methods of Experiment.
Received: 02.09.2018; Accepted: 17.04.2019; Published online: 26.06.2019.
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Optimization and analysis of neutron distribution on 30 MeV cyclotron-based double layer beam shaping assembly (DLBSA)

Bilalodin1,2,*, G. B. Suparta1, A. Hermanto1, D. S. Palupi1, Y. Sardjono3, Rasito4

1 Department of Physics, Faculty of Mathematics and Natural Science, Gajah Mada University, Yogyakarta, Indonesia
2 Department of Physics, Faculty of Mathematics and Natural Science, Jenderal Soedirman University, Pur-wokerto, Indonesia
3 Center for Accelerator Science and Technology, National Nuclear Energy Agency, Yogyakarta, Indonesia
4 Center for Science and Applied Nuclear Technology, Bandung, Indonesia

*Corresponding author. E-mail address:

Abstract: Design and optimization of double layer Beam Shaping Assembly (DLBSA) has been conducted using the MCNPX code. The BSA is configured to comply with such a construction having typically a double moderator, a reflector, a collimator, and a filter. The optimization of various combinations of materials that compose the moderator, reflector, and filter yields such quality and intensity of radiation beams that conform to the requirements for Boron Neutron Capture Therapy. The composing materials are aluminum and BiF3 for moderator, lead and graphite for the reflector, nickel and polyethylene borate for the collimator, and iron and cadmium for the filter. Typical beam parameters measured at the exit of the collimator are epithermal neutron flux of 1.1 ⋅ 109 n/cm2 ⋅ s, the ratio of epithermal neutron flux to thermal neutron and fast neutron flux 344 and 85, respectively, and the values of fast neutron and gamma dose to epithermal neutron flux 1.09 ⋅ 10-13 Gy ⋅ cm2 and 1.82 ⋅ 10-13 Gy ⋅ cm2, respectively. Analysis of epithermal neutron flux and neutron beam spectrum using the PHITS code reveals that the distribution of epithermal neutron spreads out in the DLBSA. The highest intensity is found in the moderator and decline down-stream of the collimator and filter. The spectrum of neutron beams displays a narrow spike with that peaks at 10 keV.

Keywords: optimization of DLBSA, neutron particle distribution, MCNPX code, PHITS code.


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