The system of plastic scintillator counters for the AMS experiment is descr
ibed. The main characteristics of the detector are: (a) large sensitive are
a (four 1.6 m(2) planes) with small dead space; (b) low-power consumption (
150 W for the power and the read-out electronics of 336 PMs); (c) 120 ps ti
me resolution. (C) 1999 Elsevier Science B.V. All rights reserved.