Measurements of Neutron Scattering from Carbon Using a Diamond Detector

Organic scintillators are commonly used for neutron detection at rare isotope facilities for nuclear structure studies. The majority of the total cross-section for neutrons in this energy range is due to interactions with carbon, which often result in a low scintillation light yield. The light produced is often below threshold (i.e. "dark" scattering), which introduces uncertainty into the neutron position reconstruction in measurements for which the detectors are used. To address this uncertainty, an experiment will be conducted at Los Alamos Neutron Science Center (LANSCE) in which a spectroscopic diamond detector will be used as both a target and a detector. These diamond detectors have a much lower threshold than most neutron detectors and thus can detect neutron-carbon interactions. A wall of Modular Neutron Array (MoNA) bars downstream of the diamond will be used to determine the angular distributions of the scattered neutrons. The neutron flux will be measured with fission chambers, enabling absolute cross-section measurements. This experiment will extend the empirically derived cross-section libraries to higher energies (20-200 MeV), which are relevant to the fast beam experiments performed at rare isotope facilities. These cross-sections will be used to improve simulation and in turn improve interpretation of experimental data.