Upgrade of the CSC Muon System for the CMS Detector at the HL-LHC

The Large Hadron Collider (LHC) will be upgraded in several phases to significantly expand its physics program. After the current Long Shutdown 2 (LS2) from 2019-2020, the accelerator luminosity will be increased to 2-3$\times$10$^{34}$cm$^{-2}$s$^{-1}$, exceeding the design value of 1$\times$10$^{34}$cm$^{-2}$s$^{-1}$ and allowing the CMS experiment to collect approximately 100 fb$^{-1}$ per year. A subsequent upgrade during Long Shutdown 3 (LS3) from 2024-2026 will increase the luminosity up to 7.5$\times$10$^{34}$cm$^{-2}$s$^{-1}$. The CMS muon system must sustain a physics program after LS2 that maintains the sensitivity to electroweak scale physics and TeV-scale new particle searches that has been achieved at lower luminosities. For the Cathode Strip Chamber (CSC) muon detectors, the electronics are being upgraded to handle the expected higher rates. The design of the upgraded CSC electronics will be discussed as well as the status of the first phase of the electronics installation. In view of the operating conditions at HL-LHC, it is vital to assess the detector performance at high luminosity. Accelerated aging tests are being performed to study the behavior of the CSC detectors under conditions which are nearly an order of magnitude beyond the original design values. The status and results of this irradiation campaign will be presented.