Rpc Geometry and Muon Trigger Acceptance

RPC geometry and Muon Trigger acceptance study is presented. Innuence of detector dead areas on the trigger performance is discussed. Various possible trigger algorithms are compared. Recommendations for designing RPC geometry and choosing among trigger algorithms are given. 1 RPC geometrical coverage in the barrel The CMS Muon System 1] consists of 4 muon stations (both in the barrel and in the endcaps) arranged in such a way that every high p t muon should cross active areas of at least 3 of them. Therefore, the RPC trigger 2] is based on a coincidence of 3 out of 4 stations. Thus, the geometrical acceptance of the trigger can be deened as a probability to cross at least 3 out of 4 RPC planes (denoted as MS1,2,3,4) placed in diierent muon stations. A muon with p t < 5-6 GeV cannot, however, reach outermost stations due to energy losses. In order to be able to trigger on such muons the two inner stations in the barrel are equipped with additional RPC planes, denoted as MS1' and MS2'. In this case trigger requires a coincidence of at least 3 out of 4 planes: MS1,1',2,2'.