Characterization of prototype BTeV silicon pixel sensors before and after irradiation

We report on measurements performed on silicon pixel sensor prototypes exposed to a 200 MeV proton beam at the Indiana University Cyclotron Facility. The sensors are of n/sup +//n/p/sup +/ type with multi-guard ring structures and p-stop electrode isolation. Electrical characterization of such devices was performed before and after irradiation up to proton fluence of 4/spl times/10/sup 14/ p cm/sup -2/. We tested pixel sensors fabricated from normal and oxygen-enriched silicon wafers and with two different p-stop isolation layouts: common p-stop and individual p-stop.