A Low Energy Antineutron Detector

A detector for antineutrons in the momentum range 0.1 - 1 Gev/c, to be used at LEAR faci= lity at CERN, is described. The antineutrons are detected by means of the charged pions produced in an annihilation event and their energy is determined by a time of flight mea= surement. The detector consist of 10 equal modules; each one contains: an iron slab (the converter) of 20×20×1 cm , a scintillation of the same dimensions for T.O.F. measurements, an iron sheet of 100×100×0.2 cm that stops the low energy high ionizing particles and finally a plane of limited streamer tubes with 1 cm pitch and read-out on both horizontal and vertical cohordinates. Principal features of the detector are: T.O.F. resolution of 0.5 ns, spatial resolution of 1 cm in both vertical and horizontal directions, estimated efficien= cy of 0.65.