RIKEN Compact Neutron Systems with Fast and Slow Neutrons

Abstract

RIKEN has developed accelerator-driven compact pulse neutron systems for practical use in industrial applications and non-destructive infrastructure inspection that are called RIKEN accelerator-driven compact neutron source (RANS) and RANS2. The visualization method for corrosion, the corrosion's related water movement in painted steels, the analytical method for the quantitative estimation of the water movement in painted steels, a neutron engineering diffractometer for texture evaluation, and the austenite volume fraction estimation of iron and steel have been successfully observed through slow neutron applications. For fast neutron imaging applications, a pixel imaging detector for fast neutrons with energy levels above 1 MeV has been developed and used to produce images of a steel bar and an air gap through 30 cm of concrete. The salt concentrations of 4-cm and 5-cm thick mortar blocks have been measured, and a correlation diagram was obtained for a density of up to 1 kg/m³. RANS2 is now undergoing further development, particularly for outdoor use, as the first test model of an on-site compact neutron system. In this development, RANS2 is equipped with a 2.49-MeV three-fold proton accelerator with an RFQ of 200 MHz.