Electron beam test of an iron/gas calorimeter based on ceramic parallel plate chambers

Abstract The baseline option for the very forward calorimetry in the CMS experiment is an iron/gas calorimeter based on parallel plate chambers. A small prototype module of such a calorimeter, has been tested using electrons of 5 to 100 GeV/ c momentum with various high voltages and two gases: CO 2 (100%) and CF 4 CO 2 ( 80 20 ), at atmospheric pressure. The collected charge has been measured as a function of the high voltage and of the electron energy. The energy resolution has also been measured. Comparisons have been made with Monte-Carlo predictions. Agreement between data and simulation allows to make an estimation of the expected performance of a full size calorimeter.