Development of a System for Forming a Beam of Cold Neutrons for the VITA Accelerating Neutron Source

Cold neutrons (with energy 10^–7–10^–4 eV) have found broad application in many areas of modern physics. A new and prospective field of application of low-energy neutrons is the boron neutron capture therapy of oncological illness. This method is based on neutron capture by boron-10, previously accumulated in a tumor, and reaction ¹⁰B(n,α)⁷Li with following escape of energetic α particle and lithium atomic nucleus. The delivery of cold neutrons directly to the area of a malignant tumor can make it possible to increase the localization of the therapeutic dose in the tumor, exclude any impact on healthy cells, and increase the effectiveness of boron neutron capture therapy (BNСT), both in the case of deep-lying malignant tumors and those on the surface. The research described in the article is devoted to the generation of cold neutrons on the VITA accelerator-based epithermal neutron source. This paper describes the cold neutron beam shaping assembly (BSA) that has been designed. The simulation of neutron passage through the BSA performed using Geant4 software is described. The possibility of generating cold neutrons on the VITA accelerator-based epithermal neutron source was demonstrated.