# Study of the ecological gas for MRPCs

## TL;DR

This study evaluates the performance of MRPC detectors using environmentally friendly gas mixtures, aiming to replace high GWP gases like SF6 with more sustainable options such as C3F4H2 and CF3I.

## Contribution

It introduces and tests ecological gas mixtures for MRPCs, demonstrating potential for reducing greenhouse gas emissions in high-energy physics experiments.

## Key findings

- MRPC performance with ecological gases is comparable to traditional mixtures.
- C3F4H2-based mixtures show promising timing performance.
- Adding CF3I affects the detector's avalanche behavior.

## Abstract

The Multigap Resistive Plate Chamber (MRPC) is a gaseous detector; the performance depends very much on the gas mixture as well as the design. MRPCs are used as a timing device in several collider experiments and cosmic ray experiments thanks to the excellent timing performance. The typical gas mixtures of RPC-type detectors at current experiments are based on the gases $\rm C_2F_4H_2$ and $\rm SF_6$. These gases have very high Global Warming Potential (GWP) values of 1430 and 23900 respectively. The present contribution has been performed as a part of efforts to reduce the amount of greenhouse gases used in high energy experiments. The performance of MRPC has been measured with two different gas mixtures; $\rm C_2F_4H_2$ based gas mixtures and the ecological $\rm C_3F_4H_2$ (HFO-1234ze). A small MRPC was used for the tests. It has an sensitive area of 20 $\times$ 20 $\rm cm^2$; it was been built with 6 gaps of 220 $\mu$m. In normal operation, the strong space charge created within the gas avalanche limits the avalanche's growth. $\rm SF_6$ plays an important part in the process due to its high attachment coefficient at low electric fields. It is thus necessary to find another gas that has a similar attachment coefficient. $\rm CF_{3}I$ is a possible candidate. Tests were performed with this gas added to $\rm C_3F_4H_2$.