Production and Performance of RE4 Resistive Plate Chambers for CMS experiments upgrade

The fourth trigger station composed of 144 RPCs is currently constructed to enhance the efficiency of muon triggers in the endcap regions of the CMS detector. All new CMS endcap RPC gaps are produced in accordance with QA at Korea Detector Laboratory in Korea. The qualified gas gaps passing QC have been delivered to three assembly sites; CERN in Switzerland, BARC in India, and Ghent University in Belgium for the RPC detector assembly. Here, we report the status of the detector production and the sophisticated test procedures for the selection of qualified detectors.