Semiconductor gamma-ray detector

Abstract

A novel semiconductor detector device, consisting of several layers of two dimensional detector modules each module being divided into an array of separate detector cells by means of the pixelation of the electrodes on the surfaces of the modules. The superimposed detector cells in equivalent positions in each layer are in electrical contact with those in the two immediately adjacent layers, such that the whole device effectively becomes a two dimensional array of stacks of individual detector cells, with a common bottom electrode. Current in each detector cell stack, induced by the absorption of a high energy photon in that stack, is measured by means of an integrating charge sensitive amplifier attached to each anode at the top of each cell stack. A large area gamma-ray detector, sufficiently thick to absorb the high energy photons arising from electron-positron annihilation events, is thus obtained, but without the expense associated with the production of a single detector crystal of the required thickness.