Prompt gamma facility for BNCT at RA3 reactor: Neutron beam adequation stage by simulation-guided design

A prompt gamma neutron activation analysis (PGNAA) facility is being designed and developed at the channel 4 of the RA-3 nuclear reactor, placed at the Ezeiza Atomic Center of the National Atomic Energy Commission of Argentina. The main purpose of such facility is to perform fast measurements of 10B concentration in biological samples, in the context of Boron Neutron Capture Therapy (BNCT). At this stage, a simulation guided design process has been performed for this facility. The MCNP6 code was used to perform computational simulations which have received the feedback from measurements of the implemented designs through an iterative process. The specifications of the required beam have been defined based on the sizes and types of biological samples and the lowest values of boron concentrations that would need to be measured for BNCT activities. The conformation of the neutron beam in terms of geometry and energy, has been achieved by the implementation of a system of collimators and filters. The goal of this development is to be able to measure micrograms of 10B in a few minutes of irradiation. This measurement technique needs no preparation of the samples, is reliable, robust and safe. In order to satisfy these requirements, it is necessary to provide a high thermal neutron flux E