Digitizing matrix for electron beams

In a digitizing matrix for electron beams of the type wherein electrons are permitted to pass through openings in the matrix to a target which is scanned with an electron beam and wherein the matrix comprises a series of stacked electrode units each formed by electrically-conductive layers extending transverse to each other and through which said openings pass;

• the improvement in said digitizing matrix of a low capacity single unitary structure including successive layers of thick dielectric material wherein each layer of dielectric material is in the neighborhood of 0.5 to 1 mil thick, and in-between the successive layers of the dielectric material, crossed conductors forming a plurality of crossover areas, each of said crossover areas having a predetermined combination of crossed conductors for decoding said plurality of crossover areas, each of said crossover areas having at least one opening, whereby selected crossover areas permit electrons to pass therethrough and wherein said unitary structure is in the neighborhood of 0.015 to 0.020 inches thick.