Preliminary results on optimisation of gas flow rate for ICAL RPCs

The India-based Neutrino Observatory (INO) collaboration is planning to build a magnetised Iron CALorimeter (ICAL) detector to study atmospheric neutrinos and to measure their oscillation parameters. The ICAL will use 50 kton iron as target mass and about 28,800 Resistive Plate Chambers (RPCs) of 2×2 m2 in area as active detector elements. As part of its R&D programme, a stack of 12 glass RPCs of 1×1 m2 in area has been set up to study and characterise the performance of the RPCs. In this paper, we describe our study on the optimisation of gas flow through the RPCs. We conclude that the refreshing frequency of gas can be reduced by a factor of 30 with leak free RPCs, without compromising performance of the RPCs.