  The PHENIX muon trigger upgrade adds Level-1 trigger detectors to existing
forward muon spectrometers and will enhance the ability of the experiment to
pursue a rich program of spin physics in polarized proton collisions at
sqrt(s)=500GeV. The additional muon trigger detectors and Level-1 trigger
electronics will allow the experiment to select high momentum muons from the
decay of W-bosons and reject both beam-associated and low-momentum collision
background, enabling the study of quark and antiquark polarization in the
proton. The muon trigger upgrade will add momentum and timing information to
the present muon Level-1 trigger, which only makes use of tracking in the
PHENIX muon identifier (MuID) panels. Signals from three new resistive plate
chambers (RPC's) and re-instrumented planes in the existing muon tracking
(MuTr) chambers will provide momentum and timing information for the new
Level-1 trigger. An RPC timing resolution of ~2ns will permit rejection of beam
related backgrounds.
