PSR-0125: GNASH-FKK, FKK, Preequilibrium, Statistical Model Cross-Sections and Emission Spectra

Program-name Package-ID Status GNASH-LANL PSR-0125/01 Obsolete GNASH-LANL PSR-0125/02 Obsolete GNASH-LANL PSR-0125/03 Obsolete GNASH-LANL PSR-0125/04 Obsolete GNASH-FKK PSR-0125/05 Obsolete GNASH-FKK PSR-0125/06 Tested GNASH-FKK PSR-0125/07 Tested

Machines used: Package-ID Orig.Computer Test Computer PSR-0125/06 SUN W.S. DEC ALPHA W.S. PSR-0125/07 PC Pentium 200 PC Pentium 200

3. DESCRIPTION OF PROGRAM OR FUNCTION - GNASH provides a flexible method by which reaction and level cross sections, isomer ratios, and emission spectra (neutron, gamma-ray, and charged-particle) resulting from particle-and- photon-induced reactions can be calculated. The September 1991 release of GNASH incorporated an additional option for calculating gamma-ray strength functions and transmission coefficients by including the Kopecky-Uhl model. In addition, improvements were made to the output routines, particularly regarding gamma-ray strength function information.
Major improvements in the 1995 GNASH-FKK release include added capabilities: to read in externally calculated preequilibrium spectrum from, e.g., Feshbah-Kermin-Koonin theory, to do multiple preequilibrium calculations, to calculate appropriate spin distributions for nuclear states formed in preequilibrium reactions, and to do incident-photon calculations.

PSR-0125/06:

DESCRIPTION OF PROGRAM OR FUNCTION - In the 1998 release, improvements were made in the accuracy of the exciton model and other calculations, and provision was made for including energy-dependent renormalization of the reaction cross section and energy-dependent exciton model parameterization (for data evaluation purposes).

4. METHOD OF SOLUTION - GNASH uses Hauser-Feshbach theory to calculate complicated sequences of reactions and includes a preequilibrium correction for binary tertiary channels. Gamma-ray competition is considered in detail for every decaying compound nucleus. A multi-humped fission barrier model is included for fission cross-section calculations. Three options for level densities are available.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM - In its present configuration, each calculation can handle decay sequences involving up to 38 compound nuclei and each decaying compound nucleus can emit a maximum of 5 types of radiation ( neutrons, gamma rays, protons, alphas, etc.). Angular-momentum effects and conservation of parity are included explicitly. Each residual nucleus in a calculation can contain up to 78 discrete levels whereas its continuum region can be represented by up to 204 energy bins. The incident-particle types that are permitted are neutrons, protons, deuterons, tritons, 3He and 4He. Angular distributions are not calculated; i.e., isotropy is assumed in the center-of-mass (c.m.) system. Angular distribution effects can be added in postprocessing utility codes making use of, for example, Kalbach-Mann systematics. The above restrictions can be easily adjusted by increasing the array dimensions in the parameter statements in the code.

6. TYPICAL RUNNING TIME - 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.

7. UNUSUAL FEATURES OF THE PROGRAM -

9. STATUS
PSR-0125/01: 07-FEB-1992 Obsolete
PSR-0125/02: 07-FEB-1992 Obsolete
PSR-0125/03: 12-MAR-1992 Obsolete
PSR-0125/04: 30-AUG-1996 Obsolete
PSR-0125/05: 25-JUN-1998 Obsolete
PSR-0125/06: 18-AUG-1998 Tested at NEADB
PSR-0125/07: 10-OCT-1998 Tested at NEADB

10. REFERENCES  -
- J. Kopecky and M. Uhl:
  Test of Gamma-Ray Strength Functions in Nuclear Model Calculations
  Phys. Rev. C41, 1941 (1990)
- P.G. Young, E.D. Arthur, M.B. Chadwick:
  Comprehensive Nuclear Model Calculations: Introduction to the
  Theory and Use of the GNASH Code.
  LA-12343-MS (July 1992)
PSR-0125/06:
-  M. Chadwick:
   readme.tr98 (January 1998)
-  P.G. Young, M.B. Chadwick:
   Code Input Description, Version T2/PGYC/93GNASH/GN7SRC (Update 17)
  (May 1996)
-  P.G. Young, E.D. Arthur and M.B. Chadwick
   Comprehensive Nuclear Model Calculations: Theory and Use of the GNASH code
  (to be published)  (1998)
PSR-0125/07:
-  M. Chadwick:
   readme.tr98  (January 1998)
-  P.G. Young, M.B. Chadwick:
   Code Input Description, Version T2/PGYC/93GNASH/GN7SRC (Update 17)
  (May 1996)
-  P.G. Young, E.D. Arthur and M.B. Chadwick
   Comprehensive Nuclear Model Calculations: Theory and Use of the GNASH code
  (to be published)  (1998)

11. MACHINE REQUIREMENTS - GNASH was developed originally on the CDC 6600 and 7600 then on CRAY.

PSR-0125/06:

HARDWARE REQUIREMENTS - The current release runs on Sun Sparcstations. Using GNASH and ENDF evaluations to 150 MeV, requires more than 100 MB RAM, to include all the necessary decay chains.

12. PROGRAMMING LANGUAGE(S) USED -
PSR-0125/06: FORTRAN-77
PSR-0125/07: FORTRAN-77

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED - The codes run on Cray computers under the UNICOS operating system. The gnash and search3 Fortran sources call routines which are Cray specific, but they can be ported to other Unix systems. Calls to filerep and qstart equate internal and external file names and may be removed. Substitutions need to be supplied for "date" and "second" which retrieve calendar data and time of day. Two "encode" statements in search3 may need to be changed.

PSR-0125/06:

SOFTWARE REQUIREMENTS - At RSICC GNASH-FKK was run on a Sun Sparcstation20 under Solaris 2.6 using f77 Vers. 4.2. Double precision (-r8) is needed.

PSR-0125/07:

SOFTWARE REQUIREMENTS - GNASH-FKK was run on a PC Pentium, 200MHz, 32MB RAM using a Fortran 77 Lahey system.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS -

15. NAME AND ESTABLISHMENT OF AUTHORS -
Contributed by:
                Radiation Shielding Information Center
                Oak Ridge National Laboratory
                Oak Ridge, Tennessee, U. S. A.
Developed by:
                Los Alamos National Laboratory,
                Los Alamos, New Mexico, U. S. A.

PSR-0125/07:

NAME AND ESTABLISHMENT OF AUTHORS -
                Dr Anabella TUDORA
                Bucharest University
                Faculty of Physics
                Bucharest Magurele POB MG-11
                R-76900  ROMANIA

17. CATEGORIES -

- A. Cross Section and Resonance Integral Calculations

Keywords: CROSS SECTIONS, DECAY SPECTRA, EMISSION SPECTRA, GAMMA SPECTRA, HAUSER-FESHBACH THEORY, NUCLEAR REACTIONS