The Time of Flight System and Trigger Electronics for the PAMELA Experiment in Space

The PAMELA experiment is a space-borne apparatus devoted to the study of the antiparticle component of cosmic rays. In addition The time-of-flight (ToF) scintillator system must provide the fast trigger to the experiment, the rejection of albedo particles, the possibility to distinguish electrons from antiprotons up to about 2 GeV and the measurement of the absolute charge of the particle. A readout electronics with wide dynamic range and a time resolution better than 100 ps is requested. The developed readout electronics for the PAMELA ToF system is capable of time resolution better than 50 ps with very low power consumption and has a dynamic range of about 12 bit. The developed board implements different trigger modes coming from the various subdetectors. The rate-meters of the ToF system and the logic to evaluate the live and dead time are implemented on this board, which also handles the busy signals generated by all subsystems. Since the system is destined to be carried in space, only radiation-hard (also qualified by us) components have been employed.