Charge collection properties of heavily irradiated epitaxial silicon detectors

Detectors processed on epitaxial silicon seem to be a viable solution for the extreme radiation levels in the innermost layers of tracking detectors at upgraded LHC (SLHC). A set of epitaxial pad detectors of 50 and 75 μ m thicknesses ( ρ = 50 Ω cm ) was irradiated with 24 GeV / c protons and reactor neutrons up to equivalent fluences of 10 16 cm - 2 . Charge collection for minimum ionizing electrons from a 90Sr source was measured using a charge sensitive preamplifier and a 25 ns shaping circuit. The dependence of collected charge on annealing time and operation temperature was studied. Results were used to predict the performance of fine pitch pixel detectors proposed for SLHC.