1. NAME AND TITLE
ABAREX: Neutron Spherical Optical-Statistical Model Code System.
2. CONTRIBUTOR
Argonne National Laboratory, Argonne, Illinois.
3. CODING LANGUAGE AND COMPUTER
Fortran 77; PC 486, Pentium; VAX; and others. (P00248MNYCP01).
4. NATURE OF PROBLEM SOLVED
ABAREX is an optical-statistical model program developed for the calculation and fitting of energy-averaged neutron cross sections. These include:
1. Total cross sections
2. Absorption cross sections
3. s and p wave strength functions
4. Integrated and differential shape-elastic cross sections
5. Integrated and differential compound-elastic cross sections
6. Integrated and differential elastic cross section
7. Integrated and differential inelastic cross sections for the excitation of discrete levels
8. Integrated inelastic-scattering cross sections for the excitation of continuum levels
9. -ray production cross sections
10. Radiative-capture cross sections
11. Fission and other reaction cross sections for which transmission coefficients can be supplied.
The package includes two code systems: 1) isotopic ABAREX, which was revised in the June 1999 update, and 2) Elemental ABAREX, which was added to the package in the June 1999 update. The modifications to the 1999 release of the isotopic ABAREX code were made to accomodate some European Fortran compilers and will not change results from the previous 1998 release. ELEMENTAL ABAREX is an extension of ABAREX, designed for the interpretation of neutron interactions with elemental targets consisting of up to ten isotopes. The contributions from each of the isotopes of the element are explicitly dealt with and combined for comparison with the elemental observers.
5. METHOD OF SOLUTION
The spherical-optical model algorithm of ABACUS and the statistical method of NEARREX are used with numerous modifications and improvements.
6. RESTRICTIONS OR LIMITATIONS
The program is limited to: i) neutron induced processes, ii) a maximum of 50 discrete levels, and iii) incident energies of <~ 50 MeV. The program is not relativistic. Transmission coefficients for fission and particle-producing reactions must be provided from external sources.
7. TYPICAL RUNNING TIME
Test problems run in a few seconds on Pentium 150 MHz Pcs, Micro-VAXs and VAX central facilities.
8. COMPUTER HARDWARE REQUIREMENTS
Program has run well on: 286, 386, 486 and Pentium PCs with at least 640 K memory, DEC-Alpha facilities, and on IBM RS/6000.
9. COMPUTER SOFTWARE REQUIREMENTS
MICROSOFT and Lahey FORTRAN-77 compilers have been used on the PC. VAX compilers running under VMS have been used at Micro-VAX, DEC Alphas, and VAX central facilities. The ABAREX code systems were tested at RSICC on a PC using the Lahey F77L3-EM/32 Version 5.2 compiler under Windows95 in a MS-DOS box. These executables are included in the package. The codes were also compiled on an IBM RS/6000 under AIX4.2.1 with the xlf compiler 3.2.5.4 and on a DEC Alpha OpenVMS system with Dec Fortran ver6.3.
10. REFERENCES
R. D. Lawson and A. B. Smith, "ABAREX - A Neutron Spherical Optical-Statistical-Model Code - A User's Manual," ANL/NDM-145, Rev. I (June 1999).
A. B. Smith, "Elemental Abarex - A User's Manual," ANL/NDM-147 (June 1999).
11. CONTENTS OF CODE PACKAGE
Included are the referenced documents which contain a comprehensive outline of the physical foundation, detailed operational instructions plus a number of examples and one DS/HD 3.5-inch diskette written in self-extracting compressed DOS files with the FORTRAN source files, PC executables, and test cases.
12. DATE OF ABSTRACT
March 1991, revised October 1991, August 1998, July 1999.
KEYWORDS: MICROCOMPUTER; NEUTRON; NUCLEAR MODELS