Strip detector for short-range particles

Abstract

A silicon strip detector for the coordinate determination of short range charged particles, particularly heavy ions, has been developed and investigated. The detector has 28 p +n strips made by ion implantation, the pitch is 250 μm and the interstrip distance 50 μm. The coordinates of particles incident between adjacent strips were determined by a two-dimensional amplitude analysis of the charges collected on neighboring strips. Irradiation with α-particles of 226Ra and a scanning laser beam was used. A coordinate determination accuracy better than 1 μm was obtained. In contrast to minimum ionizing particles the plasma tracks of short range particles have higher carrier densities and are located in an inhomogeneous region of the detector. The study of the charge collection times have indicated the essential role of the drift of charges in the inhomogeneous electrical field dependent on the detector geometry, the inhomogeneity of silicon and the built-in charge in the passivating oxide layer between p +n strips.