Stability studies of sealed Resistive Plate Chambers

The phase-out of hydro-fluorocarbons, owing to their high Global Warming Power, affecting the main gas used in Resistive Plate Chambers (RPCs), tetrafluoroethane C$_2$H$_2$F$_4$, has increased operational difficulties on existing systems and imposes strong restrictions on its use in new systems. This has motivated a new line of R\&D on sealed RPCs: RPCs that do not require a continuous gas flow for their operation and dispense the use of very complex and expensive re-circulation and/or recycling gas systems. At the moment it is not clear whether this solution can cover all fields of application normally allocated to RPCs, but it seems that it could be considered as a valid option for low particle flux triggering/tracking of particles, e.g. in cosmic ray or rare event experiments. In this work, we demonstrate the feasibility of a small telescope for atmospheric muon tracking consisting of four $300$~x~$300$~mm$^2$ sealed RPCs with gas gap widths of $1$~mm, $1.5$~mm and $2$~mm. The results suggest that it is possible to operate this type of detectors for extended periods of time (more than five months) with its main characteristics, efficiency, average charge and streamer probability, without apparent degradation and similar to a RPC operated in continuous gas flow.