First results on new helium based eco-gas mixtures for the Extreme Energy Events Project

TL;DR

The paper reports initial findings on environmentally friendly helium-based gas mixtures for cosmic ray detectors in the EEE Project, achieving comparable performance to traditional gases without hardware modifications.

Contribution

It introduces a new helium-based eco-gas mixture for resistive plate chambers, demonstrating its viability for large-scale cosmic ray detection.

Findings

Helium and R1234ze mixture performs comparably to traditional gases.

No hardware modifications needed for the new gas mixture.

Preliminary tests show promising environmental benefits.

Abstract

The Extreme Energy Events (EEE) Project, a joint project of the Centro Fermi (Museo Storico della Fisica e Centro Studi e Ricerche "E.Fermi") and INFN, has a dual purpose: a scientific research program on cosmic rays at ground level and an intense outreach and educational program. The project consists in a network of about 60 tracking detectors, called telescopes, mostly hosted in Italian High Schools. Each telescope is made by three Multigap Resistive Plate Chambers, operated so far with a gas mixture composed by 98% C$_2$H$_2$F$_4$ and 2% SF$_6$. Due to its high Global Warming Potential, a few years ago the EEE collaboration has started an extensive R&D on alternative mixtures environmentally sustainable and compatible with the current experimental setup and operational environment. Among other gas mixtures, the one with helium and hydrofluoroolefin R1234ze gave the best result during the preliminary tests performed with two of the network telescopes. The detector has proved to reach performance levels comparable to those obtained with previous mixtures, without any modification of the hardware. We will discuss the first results obtained with the new mixture, tested with different percentages of the two components.