Capacitance measurements on silicon micro-strip detectors for the TT station of the LHCb experiment

We studied the electrical characteristics of a total of 15 silicon detectors: 5 GLAST2000 sensors, 5 OB2-type CMS sensors, and 5 Hamamatsu LHCb Multi-Geometry sensors.The different prototypes are evaluated because they have strip geometry parameters very similar to those foreseen for the TT station of the Silicon Tracker of the LHCb experiment at CERN, and are thus well suited for initial measurements. To carry out the evaluation, measurements of the leakage current, bulk capacitance, total strip capacitance, inter-strip capacitance, coupling capacitance, and resistance of the bias resistors are made for each detector. An electrical field simulation of the various strip geometries has been performed, and its results on capacitances are compared to measurements. In view of our results, three sensors of each group have been selected to build long silicon ladders that were tested in a test beam in June 2003. We also studied prototypes of low-mass cables which are necessary in our TT design to connect the sensors to the read-out electronics.