Test beam results of closed MSGC modules for the CMS forward tracker

Abstract Inside the CMS detector 1 charged particles are measured precisely with layers of low-occupancy silicon detectors and Micro Strip Gas Chambers (MSGCs) with pitches of 50 and 200 μm, respectively. Low occupancy is achieved by a high granularity of 3×10 6 channels for silicon detectors and 11×10 6 for MSGCs. For the CMS forward tracker we tested a closed MSGC module with wedge-shaped strip patterns on 300 μm DESAG263 2 glass substrates produced by OPTIMASK. Using a 100 GeV μ-beam at CERN we investigated the behaviour of this MSGC module foreseen for four wedge-shaped substrates, 512 strips each.