The filter/moderator arrangement-optimisation for the boron-neutron capture therapy (BNCT)

Area of Science:

• Nuclear engineering
• Medical physics
• Radiation oncology

Background:

• Boron neutron capture therapy (BNCT) requires a specialized epithermal neutron source.
• Existing BNCT facilities face challenges with neutron moderation and beam contamination.
• The MARIA research reactor at Swierk presents unique design constraints.

Purpose of the Study:

• To present numerical modeling results for a novel fission-converter-based epithermal neutron source.
• To optimize the filter/moderator arrangement for BNCT at the MARIA reactor.
• To evaluate the beam characteristics, including neutron flux and contamination levels.

Main Methods:

• Numerical modeling using the MCNP code.
• Design and optimization of a fission converter.
• Development of a filter/moderator system to tailor neutron energy spectra.
• Assessment of gamma and fast neutron contamination.

Main Results:

• The proposed fission-converter design is optimized for the MARIA reactor's geometry.
• The filter/moderator arrangement effectively moderates fission neutrons to epithermal energies.
• The system achieves high epithermal neutron flux with significantly reduced fast neutron and photon contamination.
• The gamma radiation dose is reduced by one order of magnitude compared to maximum allowed levels.

Conclusions:

• The developed epithermal neutron source design is suitable for BNCT applications.
• The unique design offers exceptional reduction in photon contamination, enhancing patient safety.
• The optimized filter/moderator system ensures a high-quality therapeutic neutron beam.