1. NAME AND TITLE

EMPIRE: A Pre-equilibrium Compound Nuclear Model Code For Personal Computers.

See the PSR-497/EMPIRE II package.

2. CONTRIBUTOR

Institute of Nuclear Studies, Warsaw, Poland through NEA Data Bank, France.

3. CODING LANGUAGE AND COMPUTER

Fortran 77; IBM PC/AT.

4. NATURE OF PROBLEM SOLVED

EMPIRE calculates spectra and cross sections for capture and/or multistep nuclear reactions in the frame of a combined pre-equilibrium and compound nucleus mechanism model.

5. METHOD OF SOLUTION

Angular momentum conservation is observed throughout the whole calculation. The decay of the compound nucleus is treated either in terms of the HRTW theory, to account for the width fluctuation effects, or in terms of standard Hauser-Feshbach theory if many open particle channels cause the fluctuations to cancel. The transmission coefficients of the nuclear potential are calculated with an optical model subroutine. The full gamma cascade is included in the calculations providing the gamma spectra and populations of the discrete levels in the residual nuclei.

6. RESTRICTIONS OR LIMITATIONS

The particles considered in the code are neutrons, protons and alphas. The energy discretization of the continuum is confined to 120 points. The maximum number of partial waves is 30.

7. TYPICAL RUNNING TIME

The sample input problems (test cases 1 and 2) were run at NEA Data Bank on an IBM PC/AT with a math coprocessor. With the PROFORT compiler, problem 1 took 15 minutes, 8 seconds; problem 2 took 32 minutes, 3 seconds. With the RM/Fortran compiler, problems 1 and 2 took 8 minutes, 48 seconds and 21 minutes, 55 seconds respectively.

8. COMPUTER HARDWARE REQUIREMENTS

EMPIRE runs on an IBM PC/AT with a math coprocessor.

9. COMPUTER SOFTWARE REQUIREMENTS

The code was written in Fortran 77. The NEA Data Bank used IBM Professional Fortran version 1.0 and the RM/Fortran compiler, version 2.42 under the MS-DOS 3.20 operating system.

10. REFERENCE

A. Marcinkowski, "EMPIRE - Pre-equilibrium/Compound Nuclear Model For Personal Computer," IAEA-NDS-95 (June 2, 1988).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one DS/HD (1.2 MB) 5.25-inch diskette.

12. DATE OF ABSTRACT

November 1990.

KEYWORDS: MICROCOMPUTER; NUCLEAR MODELS; NEUTRON; PROTON