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/spl times/60 cm/sup 2/ large /sup 6/Li-glass scintillator for the neutron capture and dispersion of the emitted light on an array of photomultiplier tubes for the derivation of the event position. For subthermal neutrons of 8 /spl Aring/, 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 /spl mu/s. A fast digitalization method using free-running analog-to-digital converters for each photomultiplier combined with field-programmable gate arrays for a parallel event detection in all channels has been applied. A subsequent farm of up to 16 floating-point digital signal processors is used to provide enough computing power for an improved reconstruction of the event position according to a maximum likelihood method.