Characterization of silicon pixel detectors with the n(+)/n/p(+) and double-sided multiguard ring structure before and after neutron irradiation

The lifetime of silicon detectors in a severe radiation environment at CERN LHC depends strongly upon careful detector design and material selection, due to the anticipated radiation-induced damage. We fabricated recently mor e radiation-tolerant CMS forward pixel sensors' with new designs of silicon pixel detectors with the n(+)/n/p(+) and double-sided multiguard ring stru cture. Electrical characterization of such devices was performed before and after irradiation to neutron fluences (1 MeV equivalent) up to 6x10(14) n/ cm(2) measuring leakage current, potential distribution over the guard ring s and full depletion voltage. Studies on the radiation hardness using oxyge n-enriched silicon substrates are being presented separately[1].