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Manuscript Title: A Monte Carlo for nuclear collision geometry.
Authors: L. Ding, E. Stenlund
Program title: NUCOGE
Catalogue identifier: ABRO_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 59(1990)313
Programming language: Fortran.
Computer: ND-570.
Operating system: SINTRAN III-VSX/500.
RAM: 3K words
Word size: 32
Keywords: Nuclear physics, Nuclear reaction, Hadron Nucleus interactions, Nucleus Nucleus interactions, Nuclear collision Geometry, Monte carlo simulation.
Classification: 17.8.

Nature of problem:
The nuclear collision geometry is known to be related to the gross features of hadron-nucleus and nucleus-nucleus collisions, and to construct it the nuclear matter distribution is essential. This distribution is largely unknown, and normally some approximation must be used. It is, however, necessary for the simulation of heavy ion reactions to construct a nuclear collision geometry taking the nuclear matter distribution into account in a way consistent with present experimental findings.

Solution method:
First the nucleon density distribution of a nucleus is calculated by modifying the measured nuclear charge distribution so that the measured hadron-nucleus or nucleus-nucleus cross sections are obtained by a collision geometry based on this density distribution. There might be more than one way to achieve this goal. To select a unique modification of the charge distribution an additional requirement has been imposed. If the assumed nucleon density distribution is folded with the proton charged distribution (given by the proton form factor) the measured nuclear charge distribution should be reobtained.

The method used is based on an independent nucleon-nucleon interaction picture with a straight line geometry. No collective effect is included.

Running time:
The running time depends on the chosen projectiles and target particles. Some examples:
    p - Cu        0.06 sec/event         O - Cu        0.16 sec/event
    p - Au        0.14 sec/event         O - Au        0.62 sec/event
    p - U         0.12 sec/event         O - U         0.78 sec/event
  p - U(deformed) 0.04 sec/event       O - U(deformed) 0.32 sec/event 
It should be noted that U takes less time than Au and deformed-U takes much less time than others are due to the different rotation times of the nucleus and repeatedly shooting times.