RSICC CODE PACKAGE PSR-540

 

1.  NAME AND TITLE

GEM: Monte-Carlo Code for Simulating a Decaying Process of an Excited Nucleus.

 

2.  CONTRIBUTORS

Mitsubishi Research Institute, Inc., Tokyo, Japan through the Nuclear Energy Agency Data Bank, Issy-les-Moulineaux, France.

 

3.  CODING LANGUAGE AND COMPUTER

Fortran 77; Linux Based PC (P00540PC58600).

 

4.  NATURE OF PROBLEM SOLVED

GEM is a Monte Carlo code which simulates a decaying process of an excited nucleus. GEM calculates the types, numbers, and kinetic energies of particles emitted from an excited nucleus. An input file which includes the mass, charge, excitation energy, kinetic energy and the direction of motion of the excited nuclei produced after cascade or preequilibrium stage, is needed for execution. In order to estimate cross sections of particle productions, the output file needs to be edited.

 

5.  METHOD OF SOLUTION

The code is based on the generalized evaporation model and the Atchison fission model. Type and kinetic energy of an emitted particle are randomly selected according to the probability distribution. A simulation continues as far as evaporation is energetically possible.

 

6.  RESTRICTIONS OR LIMITATIONS

None listed.

 

7.  TYPICAL RUNNING TIME

Running time depends on the mass and excitation energy of a target.

 

8.  COMPUTER HARDWARE REQUIREMENTS

GEM runs on Linux based personal computers.

 

9.  COMPUTER SOFTWARE REQUIREMENTS

The excited energy of a residual nucleus produced after evaporation process is not written in an output file. To write this value in the output file, the following lines in 'main.f' should be modified. Add 'e1' in the write statements on line 165 and 187 (just before format statement 602 and 604), then the excitation energy of a residual nucleus can be obtained.

& write(70,602)izr,iar,erec,bet0,nocas,e1 <-- 602 format(2i4,1pe13.5,3e13.5,i7,3h B )
& write(70,604)izr,iar,erec,bet0,nocas,e1 <-- 604 format(2i4,1pe13.5,3e13.5,i7,3h D )

 

10. REFERENCES

 “The GEM Code - A Simulation Program for the Evaporation and the Fission Process of An Excited Nucleus”, Shiori Furihata, Koji Niita, Shin-ichiro Meigo, Yujiro Ikeda and Fuji0

Maekawa, Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy

Research Institute, Tokai-mura, Naka-gun, Ibaraki-ken JAPAN, JAERI-Data/Code 2001-015

(February 5, 2001).

 

 “The GEM Code User’s Manual - The Generalized Evaporation Model and the Fission Model for a Monte Carlo Simulation,” S. Furihata, Mitsubishi Research, Inc. (September 5, 2001).

 

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents along with source files, data libraries, input and output files.

 

12. DATE OF ABSTRACT

December 2012.

 

KEYWORDS:  Monte Carlo Method, Cascade, Decay, Nuclear models, Preequilibrium, Simulation