Resistive plate chambers performances at low pressure

Abstract The performance at low pressure of 2 mm gap bakelite Resistive Plate Chambers, operated in streamer mode with a gas mixture of 58% Ar, 40% n-butane and 2% CF 3 Br, have been studied. Efficiency, time resolution and strip multiplicity appear satisfactory up to pressures of about 600 mbar, corresponding to altitudes around 4000m a.s.l.