Gas recirculation and recuperation systems for Resistive Plate Chamber operation with new environmental friendly gases

Abstract

Resistive Plate Chamber (RPC) detectors are widely used thanks to their excellent time resolution and low production cost. The large RPC systems at the CERN-LHC experiments are operated in avalanche mode thanks to a R134a-based gas mixture with the addition SF6 and iC4H10 in low concentrations (0.3% and 5% respectively). However, due to their high global warming potential (GWP), R134a has been phased out from production and SF6 will be probably phased out very soon. Although R134a and SF6 will always be technically available for research purposes, their cost will probably increase as the interest of industry and market will gradually move towards new eco-friendly refrigerants and insulators. In addition, the reduction of R134a and SF6 emission in the atmosphere from anthropogenic activityis is of paramount importance because GHGs are believed to be at the origin of climate changes. Several gas mixtures based on new environmental friendly gases have been tested in the past few years. Results obtained with new gas mixtures based on hydro-fluoro-olephin (R1234ze), CO2 and C4F8O are presented. A parallel strategy for reducing the GHG emission is focused on the development of new gas recirculation and recuperation systems. The present contribution describes the last results obtained during the first test of RPC detectors operated with new environmental friendly gas mixture and new gas recirculation system. Other strategies for GHG emission reduction will be discussed as a part of a wider R&D program.