An RPC carpet covering similar to 10(4) m(2) (ARGO-YBJ experiment) will be
installed in the YangBaJing Laboratory (Tibet, People's Republic of China)
at an altitude of 4300 m a.s.l. A test-module of similar to 50 m(2) has bee
n put in operation in this laboratory and about 10(6) air shower events hav
e been collected. The RPC performance at high altitude and the carpet capab
ility of reconstructing the shower features are presented. (C) 2000 Elsevie
r Science B.V. All rights reserved.