1. NAME AND TITLE
PREM: Code System for Pre-equilibrium Process with Multiple Nucleon Emission.
Faculty of Science, Tohoku University, Sendai, Japan, through the NEA Data Bank, Gif-sur-Yvette, Cedex France.
3. CODING LANGUAGE AND COMPUTER
Fortran-4; IBM 360/370.
4. NATURE OF PROBLEM SOLVED
PREM calculates the energy spectra and distribution of excitons at each stage of a multi-nucleon
emission process when the initial exciton distribution is given. The time evolution can also be
5. METHOD OF SOLUTION
PREM solves the master equations for any number of nucleon emissions under the assumption of pre-equilibrium as well as equilibrium processes. The energy spectra of nucleons and the probability of a certain nucleus being left as the residual nucleus are calculated at each stage. Reactions may be induced by nucleons, light ions as well as heavy ions. In the last case, the initial exciton distribution function must be supplied.
All the calculations are based on the following assumptions and limitations: 1) only nucleon
emissions are considered, 2) the angular momentum conservation is not taken into account, 3) angular
distribution of emitted particle is not calculated, 4) the Erickson's formula is used for level density,
5) simple formulas are used for escape and spreading widths.
6. RESTRICTIONS OR LIMITATIONS
7. TYPICAL RUNNING TIME
No study has been made by RSIC of typical running times for PREM.
8. COMPUTER HARDWARE REQUIREMENTS
PREM is operable on IBM 360/370 computers.
9. COMPUTER SOFTWARE REQUIREMENTS
A Fortran-4 compiler is required.
G. Keeni and S. Yosida, "Computer Code for Pre-Equilibrium Process With Multiple Nucleon
Emission PREM," NEA 0888/01 (December 1982).
11. CONTENTS OF CODE PACKAGE
Included are the referenced document and one (1.2MB) DOS diskette which contains the source
code and sample problem input.
12. DATE OF ABSTRACT
KEYWORD: NUCLEAR MODELS