Radiation Induced Noise in p-n Junctions

Noise is induced in a p-n junction when it is bombarded by high-energy radiation. The mean square noise current d〈(in)2〉 is predicted to be given by d〈(in)2〉=2e2〈NB〉〈m2〉Δf,where NB is rate of incidence of bombarding particles and m is the number of hole-electron pairs which reach the junction per primary particle. Experiments performed on Ge and Si p-n junction diodes agreed with this prediction. Extension of the theory to triodes is outlined, and applications of the noise in detecting and analyzing radiation are discussed.