The scintillator detector for the fast trigger and time-of-flight (TOF) measurement of the space experiment AMS-02

The 'Time-Of-Flight' (TOF) system of the AMS-02 superconducting spectrometer, to be installed in the ISS International Space Station, consists of four layers of plastic scintillation counters. During the precursor mission AMS-01 (June 1998), a similar system successfully operated in space for 10 days. However, the AMS-02 TOF had to be redesigned taking into account the more stringent mass and power constraints of the AMS-02 detector. The main characteristics of the new TOF system are (a) capability to stand the high fringing field of AMS-02 superconducting magnet; (b) high redundancy of electronic components for unmanned operation of at least three years in the space station; (c) capability to operate in the space environment on the ISS. Counters and electronics have been extensively tested before the installation in the spectrometer.