Response of a resistive plate chamber to particles leaking laterally from a thick absorber

Resistive plate chamber detectors, working in streamer mode, have been chosen to equip the ALICE/LHC dimuon trigger. In ALICE, the detector will be placed orthogonal to a thick beam shield. Tests of the detector have been performed in order to investigate its performances in such running conditions. These tests show that resistive plate chambers can be operated in streamer mode in these particular conditions without dramatic deterioration of the overall performances. FLUKA simulations reproduce the experimental results within a factor 1.5. Such a test is not only relevant for the ALICE dimuon trigger but for all collider experiments using the RPC detector.