The high-luminosity phase of the Large Hadron Collider (HL-LHC) will result in ten times higher particle background than measured during the first phase of LHC operation. In order to fully exploit the highly-demanding operating conditions during HL-LHC, the Compact Muon Solenoid (CMS) Collaboration will use Gas Electron Multiplier (GEM) detector technology. The technology will be integrated into the innermost region of the forward muon spectrometer of CMS as an additional muon station called GE1$∕$1. The primary purpose of this auxiliary station is to help in muon reconstruction and to control level-1 muon trigger rates in the pseudo-rapidity region $1.6\le \left|\eta \right|\le 2.2$. The new station will contain trapezoidal-shaped GEM detectors called GE1$∕$1 chambers. The design of these chambers is finalized, and the installation is in progress during the Long Shutdown phase two (LS-2) that started in 2019. Several full-size prototypes were built and operated successfully in various test beams at CERN. We describe performance measurements such as gain, efficiency, and time resolution of these prototype chambers, developed after years of R&D, and summarize their behavior in different gas compositions as a function of the applied voltage.

大型强子对撞机（HL-LHC）的高发光度阶段将导致的粒子背景比LHC运行第一阶段所测得的粒子背景高十倍。为了充分利用HL-LHC期间苛刻的运行条件，紧凑型μ子电磁阀（CMS）协作将使用气体电子倍增器（GEM）检测器技术。该技术将被集成到CMS前向μ子光谱仪的最内层区域，作为另外一个称为GE1的μ子站$∕$1.该辅助站的主要目的是帮助μ子重建并控制伪快速区域中的1级μon触发率。 $\mathrm{1个}。6\le \left|\eta \right|\le 2。2$。新站将包含称为GE1的梯形GEM检测器$∕$1室。这些腔室的设计已完成，并于2019年开始的第二阶段长关闭（LS-2）中进行安装。在CERN的各种测试梁上成功制造并运行了几座全尺寸原型。我们描述了这些原型腔室的性能测量，例如增益，效率和时间分辨率，这些都是经过多年的研发而开发的，并总结了它们在不同气体成分中的行为随施加电压的变化。