EMPIRE-II 2.13 and 2.18: Comprehensive Nuclear Model Code, Nucleons, Ions Induced Cross-Sections.
AUXILIARY CODES
EMPEND: Operates on the output of EMPIRE to produce ENDF-VI formatted cross section records (A. Trkov).
PLOTC4: Plots comparison between calculated and experimental data.
XRTOC4: Converts EXFOR entries into computational format (R. Cullen).
DATA LIBRARIES
EMPIRE II 2.13:
EXFOR: Full EXFOR library of experimental data (as of July 1999).
EMPIRE II 2.18:
- orsi.liv:
Nuclear level energies, spins, parities, and gamma-ray branching ratios.
- nix-moller-audi.dat: ground-state masses, deformations and shell corrections.
- ldp.dat: level density parameters, neutron resonance spacing (Dobs).
- nparac.dat: level density parameters from the analysis of shell model
single-particle spacings.
IAEA, Vienna, Austria through the OECD Nuclear Energy Agency Data Bank, Issy-Les Molineaux, France.
Fortran 77 and C; Linux and Windows systems (P00497PC58601).
EMPIRE-II is a flexible code for calculation of nuclear reactions in the frame of combined optical, multistep direct (TUL), multistep compound (NVWY) and statistical (Hauser‑Feshbach) models. Incident particle can be a nucleon or any nucleus (heavy ion). Isomer ratios, residue production cross sections and emission spectra for neutrons, protons, alpha-particles, gamma‑rays, and one type of light ion can be calculated. The energy range starts just above the resonance region for neutron induced reactions and extends up to several hundreds of MeV for the heavy ion induced reactions. Version 2.18 corrects an error in the Absoft compile procedure.
For projectiles with A<5 EMPIRE calculates fusion cross sections using spherical optical model transmission coefficients. In the case of heavy ion induced reactions, the fusion cross section can be determined using various approaches including simplified coupled channels method (code CCFUS). Preequilibrium emission is treated in terms of quantum‑mechanical theories (TUL-MSD and NVWY-MSC). MSC contribution to the gamma emission is taken into account. These calculations are followed by statistical decay with arbitrary number of subsequent particle emissions. Gamma-ray competition is considered in detail for every decaying compound nucleus. Different options for level densities are available including dynamical approach with collective effects taken into account. EMPIRE contains following third party codes converted into subroutines: SCAT2 by O. Bersillon, ORION & TRISTAN by H. Lenske and H. Wolter, CCFUS by C.H. Dasso and S. Landowne, and BARMOM by A. Sierk.
The code can be easily adjusted to the problem by changing dimensions in the dimensions.h file. The actual limits are set by the available memory. In the current formulation up to 4 ejectiles plus gamma are allowed. This limit can be relaxed by modification of a few lines in the input.f module. Gammas are not allowed in the incident channel. Angular distributions are calculated for the MSD part of the cross section. For the remaining mechanisms isotropy is assumed in the center-of‑mass system. MSD can only be calculated for the inelastic scattering (not for the charge exchange reactions). No multiple preequilibrium is included. The preequilibrium emission of clusters is not considered.
The running times typically range from a few seconds to a few minutes per incident energy depending upon incident particle energy, mass range of the target, number of compound nuclei included, and the energy bin width that is used.
EMPIRE was initially developed on different platforms including PC, RS/6000, DEC-ALPHA and IRIX (Silicon Graphics). This current release runs on Linux and Windows systems.
The current version of EMPIRE runs under Linux Red Hat 6.1 using g77 compiler. The full functionality requires: Fortran-77 or -90 compiler, C compiler (if not integrated with the FORTRAN compiler), gnuplot, grep, awk (or gawk), bash shell, and Tcl/Tk. All of these can be obtained free of charge for practically any operating system (except of the bash shell available for UNIX only). Basic calculations should be possible on any operating system on which standard FORTRAN77 compiler is available.
M. Herman, “EMPIRE-II Statistical Model Code for Nuclear Reaction Calculations (Version 2.13 Trieste),” (April 5, 2000).
M. Herman, “EMPIRE-II Statistical Model Code for Nuclear Reaction Calculations (Version 2.18 Mondovi),” (September 27, 2002).
The package is transmitted on DVD and includes the referenced documents, source, scripts, and test problems. No executables are included with the package.
July 2012.
KEYWORDS: NUCLEAR MODELS; NEUTRON; PROTON; GAMMA RAY