Large scale gas systems for the INO ICAL detector

The 50Kton Iron Calorimeter (ICAL) detector, proposed by the INO collaboration will deploy about 30,000 Resistive Plate Chambers (RPCs) each of 4m^2 in area as its active detector detector elements. The RPCs will be operated with using a gas mixture of Freon (R134a), Isobutane and SF_6. More than 500KL of the gas mixture will be flown through the chambers each day.

We have developed two generations of gas mixing and distribution systems as part of the INO detector R&D programme, which are being used in various INO laboratories. Since the ICAL detector requires re-use of gas in order to save money and environment, we have recently developed a gas recovery and recycling system based on fractional condensation technique. We have also developed a Residual Gas Analyser (RGA) based system to monitor the purity of input gases and their mixing ratio as well to identify the contaminants in the return gas.

We will describe the design, calibration, operational and monitoring features of the gas systems. We will also present some of our preliminary results from the gas analysis studies.