A method to use CCDs as tracking devices with reduced dead time at room temperature

Abstract

We discuss in this paper a method for track reconstruction using CCD arrays in high event rate experiments. The method is based on the correlation of the information obtained from the continuous readout in opposite directions of two CCDs placed close together and the time at which a minimum ionizing particle crosses the CCDs. This time is obtained by a trigger device and is measured in units of the CCD line clock. The technique is described in detail and the results of experimental tests, performed at the CERN SPS on a prototype using commercial arrays TH7882 are discussed. Efficiencies larger than 95% have been obtained in the reconstruction of space points of beam tracks. The reconstruction algorithm is able to filter out noisy pixels up to ∼ 0.1% of the total number, thus allowing reliable operation at room temperature. These results show that both the effective readout dead time and the generation of ghost tracks can be significantly reduced.