source: trunk/documents/UserDoc/DocBookUsersGuides/PhysicsReferenceManual/latex/hadronic/theory_driven/BinaryCascade/toPrecompound.tex @ 1229

%\subsection{Transition to pre-compound modeling \editor{Johannes Peter}}
Eventually, the cascade assumptions will break down at low energies, and the
state of affairs has to be treated by means of evaporation and pre-equilibrium
decay. This transition is not at present studied in depth, and an interesting
approach which uses the tracking time, as in the Liege cascade code, remains
to be studied in our context.

For this first release, the following algorithm is used to determine when
cascading is stopped, and pre-equilibrium decay is called: As long as there are
still particles above the kinetic energy threshold (75~MeV), cascading will 
continue. Otherwise, when the mean kinetic energy of the participants has 
dropped below a second threshold (15~MeV), the cascading is stopped.

The residual participants, and the nucleus in its current state are then used 
to define the initial state, i.e. excitation energy, number of excitons, 
number of holes, and momentum of the exciton system, for pre-equilibrium decay.

In the case of light ion reactions, the projectile excitation is determined 
from the binary collision participants ($P$) using the statistical approach 
towards excitation energy calculation in an adiabatic abrasion process, as 
described in \cite{GSI1}:
$$ E_{ex} = \sum_{P} (E_{fermi}^P-E^P) $$

Given this excitation energy, the projectile fragment is then treated by the 
evaporation models described previously.