Development of a Gd-Converter GEM Neutron Detector

The Gaseous Electron Multiplier (GEM) was invented by Sauli in 1997 and is under consideration for a number of particle detection applications.(F. Sauli, "GEM: a new concept for electron amplification in gas detectors", Nucl. Inst. and Meth. A386 (1997) 531-534.) One of the advantages of the GEM is that the functions of particle detection, signal amplification and signal pickup can be separated and each individually optimized. Monte-Carlo simulation calculations for and the design of a Gd-CsI neutron converter GEM detector will be presented. A prototype multi-GEM amplifier position sensitive 10 x 10 cm^2 device with a 1 x 1 mm^2 dual charge-division pickup plane is currently under construction. Sub-mm resolution is anticipated with the optimum 5 μm Gd converter screen covered with a "spongy" CsI secondary electron emitter. Alternative detector configurations and preliminary detector test results will be presented.