Cosmic Ray Test Certification of the First 100 CMS Endcap RPCs and the Corresponding Construction Database

In June 2004, production began for the first set of Resistive Plate Chambers (RPCs), which will be installed in the endcap of the CMS experiment at the CERN Large Hadron Collider (LHC). More than 140 such “RE” chambers have been produced and about 100 of them have been tested with cosmic rays. The detectors are assembled at CERN with gas gaps made in Korea and mechanics manufactured in China. They are equipped with the final front-end electronics, as well as, high/low-voltage distribution and threshold controls. The performance of these chambers in terms of detection efficiency, noise, and cluster size during cosmic ray testing will be described. After these tests, chambers are systematically put on a high voltage stand to monitor the dark current for a longer term. Once certified, the data from each chamber are organized in a MySQL construction database to ensure traceability of key chamber components and measured chamber performance parameters. The stringent quality control and assurance criteria that have been applied for each certified chamber to be installed in CMS will be described.