Towards Sustainable Operation of LHC Detectors: Eco-Friendly Gas Mixtures and Monitoring Strategies

by Mattia Verzeroli (Universite Claude Bernard Lyon I (FR))

Tuesday 21 Oct 2025, 11:00 → 12:00 Europe/Zurich

32/1-A24 (CERN)

The operation of large gaseous detectors at the CERN LHC relies on gas mixtures containing fluorinated compounds such as R134a (C2H2F4), SF6, and CF4. These gases are essential for the performance of detectors such as Resistive Plate Chambers (RPCs) and Cathode Strip Chambers (CSCs), but they are characterized by very high Global Warming Potentials (GWPs). With increasingly stringent European F-gas regulations, the development of environmentally friendly solutions has become a priority for long-term detector operation. This seminar presents a comprehensive study on alternative gas mixtures for HPL RPCs, based on CO2 and HFO-1234ze, validated through cosmic-ray tests, irradiation campaigns at the CERN Gamma Irradiation Facility (GIF++), and test beams. In parallel, new strategies for SF6 substitution in Multigap RPCs were investigated, with Novec 4710 emerging as a promising candidate.

Beyond the development of new mixtures, sustainable operation also requires optimization of the gas systems. Recirculation and recuperation strategies were studied in detail, with dedicated gas analysis campaigns performed on the ALICE Muon Identifier (MID) and the CMS Cathode Strip Chambers (CSC). Particular attention was given to impurity build-up and fluorine ion production, monitored with dedicated instrumentation such as gas chromatographs, ion-selective electrodes, and a Single Wire Proportional Chamber. These monitoring methodologies proved effective in ensuring stable performance under LHC conditions while reducing emissions by more than 87%.

This work combines detector physics, environmental sustainability, and system engineering to provide concrete solutions for future collider experiments. The results not only support CERN’s commitment to climate goals but also contribute to a new generation of eco-friendly gas mixtures compatible with the detector technologies already in use.

 

EPDT_Seminar.pdf