The effects of hadronic radiation on silicon microstrip detectors with variable strip pitch

The effects of charged hadronic radiation on silicon microstrip detectors have been investigated. The detectors are single-sided, AC-coupled, FOXFET biased, and have a variable strip pitch (wedge detectors). Two devices were irradiated with 500 MeV protons at TRIUMF in two separate exposures. Each exposure involved a fluence greater than 1 X 1013 protons/cm2 Approximately 40 days after each irradiation, the radiation damage constant α was measured to be approximately 2 X 10-17 amps/cm. Using capacitance versus voltage (CV) measurements, a time dependent increase in the depletion voltage has been observed with an annealing time constant of approximately 100 days. Furthermore, the frequency dependence of the sensitivity (depletion slope) has exhibited a similar annealing behavior. A model has been constructed by extending that of Li and Kraner to account for this effect