Radiation hardness of the HERA-B double-sided silicon strip detectors

Irradiation studies of double-sided silicon strip-detectors for the HERA-B experiment have been performed using a setup at a 21 MeV proton beam. A novel method of fluence monitoring has been implemented. The study presented here gives results of a non-uniform irradiation of two HERA-B detector modules built with double-sided detectors made of oxygenated as well as non-oxygenated wafers. The maximum exposed fluence corresponds to about 3×10 14 MIP / cm 2 . The characterization of the detectors was done with a laser and a 106 Ru source. In regions of low-radiation dose, signal over noise ratios of 22 and 16 were measured for n- and p-side, respectively. In the region of maximum fluence, S/N values of ≈17 and ≈15 were obtained at a bias voltage of 450 V for n- and p-strips, respectively. Our measurements establish for both detector types full functionality at fluences varying by two orders of magnitude. Standard and oxygenated detectors do not show any significant difference.