标题： 寻找ALICE电阻板室的环保型气体混合物 显示英文标题

标题： Searching for an eco-friendly gas mixture for the ALICE Resistive Plate Chambers

摘要： ALICE的RPCs使用由89.7%$C_{2}H_{2}F_{4}$、10% i-$C_{4}H_{10}$和0.3%$SF_{6}$组成的混合气体。 $C_{2}H_{2}F_{4}$和$SF_{6}$是具有高全球变暖潜能值（GWP）的氟化温室气体。 新的欧洲联盟法规已对F气体的生产和使用实施逐步减少，旨在到2030年将它们的排放量比2014年减少三分之二。 尽管研究活动不受这些法规限制，但逐步减少将不可避免地提高它们的价格，CERN也旨在减少其排放量。 出于这些原因，在2026年预计进行的LHC长期停机期间之前，找到一种更环保的RPC气体混合物至关重要。 由于$C_{2}H_{2}F_{4}$是混合物 GWP 的主要贡献者，因此已经开始了广泛的 R&D 过程，以将其替换为四氟丙烯 ($C_{3}H_{2}F_{4}$)，因其与$C_{2}H_{2}F_{4}$化学相似且 GWP 低（约为 7）。 宇宙射线的初步测试在探测器性能方面显示了有希望的结果。 下一步是研究使用这些新气体混合物的 RPC 的长期行为（老化研究）。 由于这是所有（而不仅仅是）LHC 实验感兴趣的主题，建立了一个名为 ECOgas@GIF++ 的合作项目来进行联合研究。 其中，在 CERN 的伽马辐照设施中安装了一个类似 ALICE 的小型 RPC，它们被暴露在一个强辐射场中，该辐射场来自一个 12.5 TBq 的$^{137}$Cs 源，这使得可以在相对较短的时间内模拟多年的运行。 该设施还在每年特定时间提供μ子束，可用于在辐照期间和之后研究探测器性能（例如效率和簇大小）。 显示英文摘要

摘要： The ALICE RPCs are operated with a mixture of 89.7% $C_{2}H_{2}F_{4}$, 10% i-$C_{4}H_{10}$ and 0.3% $SF_{6}$. $C_{2}H_{2}F_{4}$ and $SF_{6}$ are fluorinated greenhouse gases with a high Global Warming Potential (GWP). New European Union regulations have imposed a progressive phase-down of the production and usage of F-gases, aiming to cut down their emission by two thirds in 2030 with respect to 2014. Even though research activities are excluded from these regulations, the phase-down will inevitably increase their price and CERN is also aiming to cut down on its emissions. For these reasons it is crucial to find a more eco-friendly gas mixture for RPCs by the time of the LHC long shutdown 3, foreseen in 2026. Since $C_{2}H_{2}F_{4}$ is the main contributor to the mixture GWP, an extensive R&D process has started to replace it with tetrafluoropropene ($C_{3}H_{2}F_{4}$), due to its chemical similarity with $C_{2}H_{2}F_{4}$ and its low GWP (around 7). Preliminary tests with cosmic rays have shown promising results in terms of detector performance. The next step is to study the long-term behavior of RPCs operated with these new gas mixtures (aging studies). Since this is a subject of interest for all (and not only) the LHC experiments, a collaboration, ECOgas@GIF++, was setup to carry out joint studies. Among others, a small ALICE-like RPC was installed at the Gamma Irradiation Facility at CERN, where they are exposed to a strong radiation field, coming from a 12.5 TBq $^{137}$Cs source, which allows one to simulate many years of operation in a relatively short time. The facility also provides a muon beam at specific times of the year, which can be used to study the detector performance (e.g. efficiency and cluster size) during and after irradiation.