Study of the directionality of cosmic muons using the INO-ICAL prototype detector

The India-based Neutrino Observatory (INO) collaboration is planning to build a magnetised Iron-CALorimeter detector (ICAL) to study atmospheric neutrino oscillations with high precision. The ICAL adopts a 50 kton iron target and about 28 800 Resistive Plate Chambers (RPC) of 2×2 m2 in area as active detector elements. As part of its R&D programme, a prototype detector stack composed of 12 layers of glass RPCs of 1×1 m2 in area has been set up at the Tata Institute of Fundamental Research (TIFR) to study the detector parameters using cosmic muons. We present here a study of the capability of this prototype detector to distinguish between up-going and down-going muons.