  A brief description of our improvements and refinements that led from the
CEM95 version of the Cascade-Exciton Model (CEM) code to CEM97 and to CEM2k is
given. The increased accuracy and predictive power of the code CEM2k are shown
by several examples. To describe fission and light-fragment (heavier than 4He)
production, the CEM2k code has been merged with the GEM2 code of Furihata. We
present some results on proton-induced fragmentation and fission reactions
predicted by this extended version of CEM2k. We show that merging CEM2k with
GEM2 allows us to describe many fission and fragmentation reactions in addition
to the spallation reactions which are already relatively well described. We
have initiated another approach to describe fission, complex particles and
fragment emission by developing further our CEM2k code addressing specifically
these problems. In this effort, we have developed our own universal
approximation for inverse cross sections, new routines to calculate Coulomb
barriers and widths of emitted particles and to simulate their kinetic energy
using arbitrary approximations for the inverse cross sections. To describe
fission-fragment production, we have incorporated into CEM2k a thermodynamical
model of fission by Stepanov. This extended version of CEM2k allows us to
describe much better complex particle emission and many fission fragments, but
it is still incomplete and needs further work.
