A MODEL OF CHARGE COLLECTION IN A SILICON SURFACE-BARRIER DETECTOR

Charge collection process in a silicon surface barrier detector (SSB) was investigated as a following phenomenon of the formation and erosion of a plasma column the author reported elsewhere [Rev. Sci. Instrum. 58, 1926 (1986)]. As an application of Ramo's theory, a model of charge collection process was presented. With this model, the top and bottom position and disappearance time of a plasma column were determined analytically. The induced currents and charges were calculated for alpha particle and 40Ar ion whose plasma delays were determined as a function of field strength by other authors' experiments. The contributions of electrons and holes to the induced currents and charges were determined separately. The times of the plasma column disappearance and the last hole arrival to the negative electrode, and the maximum induced currents were tabulated. The peak time of the induced currents became slightly longer as the bias voltage of the SSB increased from 50 to 200 V.