Leakage current of CMS single-sided strip sensors under neutron irradiation

The Large Hadron Collider (LHC) at CERN is a proton–proton collider with a maximum luminosity of 10 34 / cm 2 s and will be working for 10 years. The Compact Muon Solenoid (CMS) will be one of the four general purpose detectors. To guarantee the functionality of the 24 328 single-side silicon sensors under the heavy irradiation environment of the LHC a fraction of all sensors have been irradiated in the two Irradiation Qualification Centers (IQC) in Karlsruhe (Germany) and Louvain-la-Neuve (Belgium). In Karlsruhe, the sensors are irradiated with 26 MeV protons and in Louvain-la-Neuve with neutrons at an average energy of 20 MeV. For at least a few hundred sensors from one of the two manufactures, large differences in sensor quality are observed. Most of these sensors have single strips with a significantly too high leakage current. The total and single strip leakage currents have been measured before, during and after irradiation and are presented in the following sections.