Ultimate limits for the radiation hardness of silicon strip detectors for sLHC

The new SuperLHC upgrade will impose severe restrictions on the radiation hardness of silicon detectors since a maximum fluence of 10 particles/cm is foreseen in the innermost region. Microstrip detectors have been fabricated in p-type high resistivity float zone silicon at CNM facilities, been irradiated at the TRIGA reactor in Ljubljana to a fluence of 10 neutrons/cm and characterized at IFIC laboratory. The total collected charge before and after irradiation in the detectors has been measured by Sr beta source and by infrared laser illumination. The results show that even after this extreme radiation fluence, p-type substrate detectors collect 3 500 electrons when biased at 800 V, which is enough charge to induce a measurable signal with standard readout electronics. P-type strip detectors could be suitable for the middle and even inner regions of sLHC.