The ToF system of the PAMELA experiment: In-orbit performance

A time-of-flight scintillator system (ToF) has been developed for the PAMELA satelliteborne cosmic ray experiment, mounted on the Resurs DK1 satellite and launched from the Baikonur cosmodrome on June 15 2006. PAMELA was built to measure charged particles in the cosmic radiation with a particular focus on antiparticles. The ToF scintillator system provides the fast trigger to the experiment, the rejection of albedo particles, and in combination with a magnetic spectrometer the possibility to distinguish electrons from anti-protons up to about ~1 GeV and to separate light isotopes at low energies. Ionising energy loss measurements in the scintillator planes allow the absolute charge of traversing particles to be determined. The in-orbit performance of the ToF system is pre-