Analysis of testbeam data of irradiated silicon prototype sensors for the CMS tracker upgrade

CMS is working on identifying suitable radiation-hard silicon materials for the tracker upgrade in the high luminosity era of LHC. A large number of 6 in. wafers made from p and n-type, float zone, Magnetic Czochralski and Epitaxial Silicon in thicknesses ranging from 50 to 320 μ m were ordered from Hamamatsu. The wafers contain many different test structures as well as strip sensors called Multi Geometry Silicon Strip Detector (MSSD), that feature pitches from 70 to 240 μ m and different strip widths. The structures were irradiated to a fluence of 1.5×1015 1 MeV Neq cm−2 which corresponds to the fluence that the sensors will receive in a future tracker at a distance of 20 cm from the beam. This contribution will focus on the results obtained in various test beams with these strip sensors. The evolution of parameters such as resolution, signal and noise with increasing fluences will be addressed as well as the relation between geometry, thickness and technology.