Monte Carlo intercomparison and benchmark of the neutron streaming in the ramified access maze of the CERN High-energy AcceleRator Mixed field (CHARM) facility at CERN

Abstract

Experiments of high-energy neutron streaming were performed in the access maze of the CERN High-energy AcceleRator Mixed-field (CHARM) facility where high-intensity proton beams of 24 GeV/c impact on a copper target. The streaming of the secondary neutrons through the various legs of the ramified access maze of the facility was measured using aluminium activation detectors installed at 12 different locations: for the first time, the extended coverage of measurement locations allowed to assess the streaming in more distant areas of the maze. The attenuation profile along the maze measured via the production of 24Na was also used to benchmark results from Monte Carlo calculations performed with FLUKA, PHITS, and GEANT4: over almost the five orders of magnitude of the measured production yield, an agreement within a factor 1.4, 1.7, and 2.5 respectively was found for the three codes.