Figure 1 shows the geometry of the muon arms
in the PHENIX detector. The material that particles pass
through before reaching the muon tracking stations consists
of a copper nose cone (which is 28 cm thick in the North arm and
12 cm in the South arm) and the
central magnet return yoke which is 59 cm of steel. The first
and last muon tracking stations in each arm contain chambers made
of honeycomb material which are approximately 5.7% radiation
lengths thick and the central tracking stations are low-mass
chambers which are approximately 0.3% radiation lengths thick.
The baseline tracking stations each consist of three cathode
strip chambers (CSCs) which are comprised of one fine cathode
plane, with a resolution of approximately 100 
m, one
coarse cathode plane which is at a stereo angle of 
to the fine cathode plane and has a resolution of approximately
3 mm and an anode plane which is perpendicular to the fine
cathode plane and has a resolution of approximatley 3 mm.
This gives a station resolution on the order of
100
m/sqrt(3) or 58 
m.
Figure 1: The absorber materials and muon arms of the
PHENIX detector, as
represented in the simulations. The left side is
the South muon arm and the right side is the North
muon arm.