Speaker
Description
The gas mixtures employed in most RPC systems contain a high fraction of fluorinated greenhouse gases (F-gases), namely C2H2F4 (R134a) and SF6, which have been placed under intense scrutiny by the EU, aiming at a reduction in their availability and usage, making RPC operation more costly and less sustainable.
A possible long-term solution to this problem is to find eco-friendly alternatives to these gases. The RPC EcoGas@GIF++ collaboration investigated the full replacement of R134a with its industrial substitute, the tetrafluoropropene (C3H2F4 or simply HFO) diluted with CO2 in different concentrations. The studies consisted in carrying out several beam test campaigns and aging studies to investigate the RPC performance in terms of detection efficiency, prompt charge and long-term operational stability.
This contribution will present a complementary approach to the studies carried out thus far, where the focus of the research is shifted from RPC performance to detailed material studies of RPC components, before and after being exposed to HFO/CO2 mixtures, in different experimental conditions.
A variety of analytical techniques (Scanning Electron Microscope (SEM), coupled with Energy Dispersive X-ray (EDX), laser microscopy and resistivity measurements) have been applied to brand-new and aged materials, in an attempt to gain a deeper insight of the electrical and chemical modifications induced by the new gases. An overview of the obtained results and potential explanations for the observed effects will be reported in this contribution.