Assembly, testing, and installation of the fast RPC muon trigger upgrade for PHENIX

Many important questions remain to be answered about the origin of the proton spin. A new fast resistive plate chamber (RPC) based trigger system is being developed for the PHENIX muon spectrometer arms that will allow, for the first time, the measurement of the flavor structure of the quark polarization in the proton through the observations of W-bosons in polarized proton–proton collisions at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). The new PHENIX muon trigger will improve the efficiency by which the data acquisition system can identify potential W events by approximately two orders of magnitude. W-bosons can be detected through the appearance of a high-energy muon in one of the two existing muon spectrometers. The trigger upgrade is based on new front-end electronics for the muon tracking chambers and RPCs that will be installed in three stations of both muon arms starting with prototype chambers in 2008. Components of the RPCs are being fabricated at many different locations around the world. After they are shipped to BNL, these components will be tested and then the RPC modules will be assembled at a newly completed facility. Once assembled, these modules will be extensively tested and joined in half octant units for installation into the PHENIX spectrometer. Prototype chambers have been assembled and tested.