NeuLAND: Simulations for the Scintillator Concept

Within the scope of the R3B experiment at FAIR, a highly efficient time-of-flight spectrometer for high-energy neutrons (200 to 1000 MeV) is developed, called NeuLAND (new Large Area Neutron Detector). The design goals and an overview of the project is given in the contribution of T. Aumann et al. [1]. Here we present the detector concept based on a fully active detector built with only organic scintillator (BC408). The simulations started with a comparison of such a design with the functionality of the existing LAND detector [2], based on alternating layers of iron converter and scintillator. The efficiency for the full neutron energy range is shown in table 1 for a 2 x 2 x 2m pure scintillator detector and for LAND. We observe for the fully active structure a significantly enhanced efficiency for the lower neutron energies. More detailed simulations carried out both in GEANT3/FairRoot and in FLUKA show in addition a substantial improvement of the detected positions and times with respect to the primary interaction, when comparing fully active structure to structures with passive layers.