  Measured J/Psi production cross sections for 200 and 450 GeV/c protons
incident on a variety of nuclear targets are analyzed within a Glauber
framework which takes into account energy loss of the beam proton, the time
delay of particle production due to quantum coherence, and absorption of the
J/Psi on nucleons. The best representation is obtained for a coherence time of
0.5 fm/c, previously determined by Drell-Yan production in proton-nucleus
collisions, and an absorption cross section of 3.6 mb, which is consistent with
the value deduced from photoproduction of the J/Psi on nuclear targets.
