Test beam results of a proton irradiated Czochralski silicon strip detector

We report on test beam results obtained with a 32.5 cm2 microstrip detector processed on an n-type 380 μm thick magnetic Czochralski (MCZ) grown silicon substrate with 1200 Ωcm effective resistivity. The full depletion voltage of the as-processed detector was 420 V with a leakage current of 2 μA. The AC coupled detector had 1024 p+ strips, 10 μm by width and 6.154 cm by length with a pitch of 50 μm. The detector was irradiated with 10 MeV protons to 1.6×1014 1 MeV neutron equivalent fluence and annealed for 345 days at room temperature. The post-irradiation full depletion voltage of the detector was 225 V. The leakage current at the full depletion measured at −10 °C was 261 μA. The beam tests were carried out at the CERN H2 area using a Silicon Beam Telescope, which consists of pairs of horizontal and vertical position sensitive silicon detectors. This telescope determines the tracks of incoming particles and hence provides a reference measurement for the detector characterization. In the beam test an average signal to noise ratio of 3 with a spatial resolution of 20 μm and a particle detection efficiency of 36% were measured. These results show that the MCZ device detected particles, which encourages further investigations of MCZ silicon as a detector material. The poor performance of the MCZ detector may be explained by the problems observed in the reference telescope.