Theoretical and experimental gain of electron-excited silicon targets

A theoretical model for target gain of electron-excited silicon diode array targets is developed. Its validity is established by comparison with experimental data and it is then used to study the gain dependence on n+layer, "dead" layer thickness, surface recombination velocity, lifetime, target thickness, and electron energy. Because the theory deals directly with the "dead" layer, the n+diffusion region and the built-in electric field rather than utilizing the concept of an effective surface recombination velocity, it allows a physical insight into the effects of the various target parameters on target gain. Conditions for maximum gain are established as well as those necessary for particular gain curves such as might be desired for variable image section gain operation.