A PROTOTYPE MONOLITHIC PIXEL DETECTOR

The performance of a monolithic pixel detector with both detecting elements and readout circuitry in the same piece of high-resistivity silicon and providing three-dimensional position information is described. The basic pixel cell is 34 X 125 mum2. The most-probable signal for a minimum-ionizing particle was observed to be 65 times the single-channel, root-mean-square noise in a muon beam. With different off-chip electronics, used with a gamma-ray source, the noise was found to be 2.3 times lower. A spatial resolution of 2.0 mum was obtained in the direction of 34 mum pitch for normally incident high-momentum muons. For tracks of up to 56-degrees to the normal the spatial resolution was under 7 mum. Results of a simulation program for calculating charge spreading and drift times are presented and compared with observations.