Comparison of irradiated stFZ silicon sensors using LHC speed front-end electronics

Results from irradiated detector modules assembled with sensors made out of standard p-in-n FZ silicon will be presented. The modules were read out using LHC speed front-end electronics and characterised with different techniques. Two complementary methods to generate the charge inside the sensor were used: An IR laser set-up with a wavelength of λ=982nm and a β set-up utilising a 90Sr source allowing for both relative and absolute CCE measurements. As the aim of our measurement programme is to develop silicon detectors able to operate at the sLHC, these modules were irradiated with three different fluences with the highest corresponding roughly to the fluence expectations for an LHC luminosity upgrade at a radial distance of r≈35cm [M. Huhtinen, First CMS Upgrade Workshop, CERN, February 26-27, 2004. 〈http://agenda.cern.ch/fullAgenda.php?ida=a036368〉]. The sensors were characterised before and after irradiation with 26 MeV protons. After irradiation the modules were stored at temperatures below -40∘C and operated at temperatures around -5∘C to limit the leakage current and annealing effects. The full depletion voltage Vfd and the charge collection efficiency have been measured.