INELASTIC QUASI-PARTICLE SCATTERING AND MULTIPLICATION IN SUPERCONDUCTORS

We report a theoretical and experimental study of quasiparticle multip lication in superconductors. A model of the multiplication process, ba sed on random quasiparticle-phonon inelastic scattering, has been comp ared with experimental data obtained from double tunnel junction devic es in which the quasiparticle injection energy can be varied by alteri ng the bias voltage. Excellent quantitative agreement has been obtaine d for a variety of device structures provided that a previously uniden tified quasiparticle energy enhancement process is included in the mod el. The existence of this energy enhancement process has implications for quasiparticle trapping and multiplication in practical energy reso lving detector devices.