A model of dielectric plasma columns in silicon surface barrier detectors

摘要

For a comprehensive understanding of the energy and timing responses of silicon surface barrier detectors (SSBDs), a model of dielectric plasma columns is proposed. The electric properties of a plasma column are assumed to change from those of a conductor to a dielectric, as the electron-hole pair density of the plasma column decreases. The time duration of conducting plasma column is regarded as the plasma delay; the time retardation between heavy ion incidence and its detector output. The electric field strengths inside the depletion layer of SSBDs are shown with a dielectric plasma column, which explain the dependence of the plasma delay on the resistivity of SSBDs. The change of the electric field strength during the charge collection process in the depletion layer of the SSBD is essential to explain the residual defect (which was previously explained as recombination defect of electrons and holes) in the pulse height defect; the non-linearity between the energy of incident heavy ion and its pulse height. Calculated results for the plasma dealy and the resuidual defect based on the present model show good agreement with experimental results of other workers and of the present author for heavy ions such as ~4He, ~(16)O, ~(40)Ar, and ~(58)Ni.