A new two-dimensional scintillation detector system for small angle neutron scattering experiments

A new two-dimensional position sensitive detector system for small angle neutron scattering experiments is under development. It is based on a 60×60 cm² large ⁶Li-glass scintillator for the neutron capture and a dispersion of the emitted light on an array of photomultiplier tubes for the derivation of the event position. For subthermal neutrons of 8 Å, an efficiency of 96% and a spatial resolution of 8 mm are to be achieved. Major improvements have been made in the signal and data processing branch, which aims at an electronic dead time of 1 μs. A fast digitalization method using free running ADCs for each photomultiplier combined with FPCAs for a parallel event detection in all channels have been applied. A subsequent farm of up to 16 floating point DSPs is to provide enough computing power for an improved reconstruction of the event position according to a maximum likelihood method