Boron Neutron Capture Therapy (BNCT) is a binary radiation therapy with strong targeting and high energy transfer line density at the cellular scale. It has the advantages of short treatment cycle and minimal damage to surrounding healthy tissues, making it a promising cancer treatment method.

This study aims to design beam shaping assembly (BSA) to make the neutron beam of D-Be neutron source suitable for BNCT and ensure neutron directionality.

The Monte Carlo simulation programs GEANT4 and FLUKA were employed to simulate the generation of ⁹Be(d,n)¹⁰B reaction neutron sources and subsequent neutron moderation. Then, a scheme design for BSA was carried out using a 1.45 MeV, 30 mA deuterium beam to bombard a 9 μm thin beryllium target, and set a basis BSA model with a cylindrical structure as a whole.

The simulation results show that using a 20 cm thick BiF₃ and 30 cm thick MgF₂ combined slowing layer, a 30 cm thick Pb reflector layer, a 9 cm thick MgF₂ supplementary slowing layer, and a 0.2 mm thick Cd thermal neutron absorption layer, the outlet is ensured to γ and fast neutron composition, Φ_epi/Φ_th, Φ_epi/Φ_fast meets the recommended values of the IAEA (International Atomic Energy Agency).

This study obtained the neutron spectra and BSA specific design scheme of low-energy deuterium beams and thin beryllium targets, providing data reference for the slowing shaping of neutrons in D-Be neutron sources and supporting subsequent research on D-Be sources.