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Description
Resistive Plate Chambers are one of the most used types of particle detectors in High Energy Physics since the 1980s. They offer advantages such as good time resolution and high-rate capability. They can be assembled using simple and cost-effective materials and gas mixtures, such as tetrafluoroethane. However, impurities in the gas can distort the signals or even damage the detector shortening its lifetime. In this study, the composition of different commercially available tetrafluoroethane supplied by different manufacturers was investigated using an ambient-pressure quadrupole mass spectrometer with ppm-level sensitivity. The experimental setup allows the direct analysis of gas composition without prior sample preparation, enabling the identification of residual atmospheric contaminants, moisture and trace molecular species over a mass range extending to 200 amu. The measurements were performed under controlled gas-flow conditions, providing a systematic comparison of the different commercial products available to RPC laboratories. Beyond the comparison of gas purity among different suppliers, this work provides a detailed interpretation of the characteristic fragmentation pattern of tetrafluoroethane under electron-impact ionization. Since similar ionization mechanisms govern the interaction of energetic electrons with gas molecules in gaseous detectors, the identified fragmentation pathways provide a valuable reference for the interpretation of molecular species and decomposition products generated during detector operation and aging studies.