1 research outputs found
Optimization of the photoneutron target geometry for e-accelerator based BNCT
Background and aim: Today, electron accelerators are taken into consideration as photoneutron sources.
Therefore, for maximum production of epithermal neutron flux, designing a photoneutron target is of significant
importance. In this paper, the effect of thickness and geometric shape of a photoneutron target on neutron output
were investigated.
Methods: In this study, a pencil photon source with 13, 15, 18, 20 and 25 MeV energies and a diameter of 2 mm
was investigated using Monte Carlo simulation method using MCNP code. To optimize the design of the
photoneutron target, the tungsten target with various geometries and thicknesses was investigated.
Results: The maximum neutron flux produced for all target geometries and thicknesses occurred at neutron energy
peak of around 0.46 MeV. As the thickness increased to 2 cm, neutron flux increased and then a decreasing trend
was observed. For various geometrical shapes, the determining factor in photoneutron output was the effective
target thickness in the photon interaction path that increased by the increase in the area of interaction. Another
factor was the angle of the photon's incidence with the target surface that resulted in a significant decrease in
photoneutron output in cone-shaped targets
Conclusion: Three factors including the total neutron flux, neutrons energy spectrum, and convergence of neutrons
plays an important role in the selection of geometry and shape of the target that should be investigated considering
beam shaping assembly (BSA) shap