  The heavy ion physics approach to global event characterization has led us to
instrument the forward region in the PHENIX experiment at RHIC. In heavy ion
collisions this coverage yields a measurement of the "spectator" energy and its
distribution about the beam direction. This energy flow is the basis of
event-by-event determination of the centrality and reaction plane which are key
to analyzing particle production in heavy ion collisions. These same tools have
also enabled a unique set of measurements on inelastic diffraction with proton,
deuteron and gold ion beams in the PHENIX experiment. We present first new
results on this topic and discuss briefly the opportunity for diffractive
physics with Heavy Ion beams at the LHC.
