Razi Journal of Medical Sciences

  Background : Performing successful BNCT experiments needs a suitable neutron source. Important factors of the neutron beam are flux and energy that are very important in the selection of neutron source. In most centers that use this method for treatment, reactor is a neutron source, which according to characteristics of the reactor appropriated neutrons are very high. High cost of constructing a BNCT center with using of reactor caused seeking other sources such as accelerator indirectly and radioisotope source directly that each has their own advantage and disadvantages. In this paper we created neutron beam by analysis Am-Be neutron source, using neutron filter technique and suitable moderators. The advantages of Am-Be neutron source are being inexpensive, easy portability, small size and well-designed shields. Therefore, by analyzing radioisotope neutron sourcesand Am-Be neutron source specially, we can prepare possible analysis radioisotope neutron source at boron neutron capture therapy. We hope to achieve suitable results by more studies.

  Methods: Neutron beam in 1keV energy created with using Am-Be neutron source and designed suitable neutron filter with using neutron absorbent materials that it will be used in testing BNCT. By studying and Identifying various materials such as oxides Alumina, graphite and beryllium as a moderator and materials such as boron, cadmium and titanium as absorbent materials to a cylindrical crust in filter has been used. Neutron Filter has been designed in the investigation of two parts. The first is consisting of a moderator with high scattering and very low percent and it is caused the fast Neutron servant brought back his spectrum Am-Be source in this without mono-energetic to the low energy transferred spectrum. Part II filter is consisting of the elements of boron, cadmium and titanium that are absorbent neutron with various energy, therefore they can exchange these neutrons in certain energy to mono-energetic. More analysis, study and designing suitable neutron conductors for increase neutron flux is recommended.

  Results: Neutron filter passes neutron with energy 1keV that can be used in the BNCT experiments. According to data obtained from the implementation MCNP4C code, a peak is obtained in energy 1keV that indicate area under the flux 2.22E-05 n/cm².s with error 0.0065 for a neutron. Flux obtained can be multiplied at the Am-Be source of power that is equal 10⁸n/cm².s until the total flux to be achieved. The total flux is obtained 2.22E+03n/cm².s at 1 cm². We must multiply total intensity at total area to achieve total neutron flux, Since the flux required for the BNCT experiments is 5*10⁸n/cm².s with using different ways and designing suitable reflectors and conductors, this neutron flux will be provided.

  Conclusion: This paper analyzed possible use of radioisotope neutron source by simulation Am-Be neutron source. We can solve many problems that exist for reactor source paying attention to characteristics of radioisotope sources such as being inexpensive, easy portability and small size also more studies are present in this base. Of course, with completing this simulation, we can be hopeful for practicality and remedy of patients in Iran.