  The production of phi mesons in proton collisions with C, Cu, Ag, and Au
targets has been studied via the phi -> K+K- decay at an incident beam energy
of 2.83 GeV using the ANKE detector system at COSY. For the first time, the
momentum dependence of the nuclear transparency ratio, the in-medium phi width,
and the differential cross section for phi meson production at forward angles
have been determined for these targets over the momentum range of 0.6 - 1.6
GeV/c. There are indications of a significant momentum dependence in the value
of the extracted phi width, which corresponds to an effective phi-N absorption
cross section in the range of 14 - 21 mb.
