Beam test results for the RAPS03 non-epitaxial CMOS active pixel sensor

Recently our group has been investigating the possibility of using a standard CMOS technology – featuring no epitaxial layer – to fabricate a sensor for charged particle detection. In this work we present the results obtained exposing sensors with 256×256 pixels ( 10 × 10 μ m pixel size, two different pixel layouts) to 180 GeV protons and positrons at the SuperProtoSynchrotron facility (CERN). We have investigated the different response of the two architectural options in terms of S/N, cluster width, intrinsic spatial resolution, efficiency. The results show a good Landau response, S/N about 22 with an average cluster size of 4.5 pixels, and an intrinsic spatial resolution of 1.5 μ m (order of 1/7th of the pixel size).