1. NAME AND TITLE

STAPRE-H95: Code System to Calculate Energy-Averaged Cross Sections of Particle Induced Nuclear Reactions.

2. CONTRIBUTOR

Institute for Physics and Nuclear Engineering, Bucharest-Magurele, Romania through the NEA Data Bank, Le Seine Saint-Germain, France.

3. CODING LANGUAGE AND COMPUTER/OPERATING SYSTEM

Fortran 77; IBM PC (P00325/MNYCP/01).

4. NATURE OF PROBLEM SOLVED

Calculation of energy-averaged cross sections of particle induced nuclear reactions with emission of particles and gamma rays, and fission. The models employed are the Hauser-Feshbach-Moldauer statistical model including a gamma-ray cascade model, and the pre-equilibrium (PE) emission exciton and Geometry-Dependent Hybrid (GDH) models. The optical-potential transmission coefficients are calculated internally by using the optical model code SCAT-2.

5. METHOD OF SOLUTION

Integrations in connection with the composite system de-excitation and residual nuclei population are approximated by summation over equal size energy bins. For the gamma-ray cascades a recursion formula is employed. The Moldauer width-fluctuation correction factor is calculated by use of Simpson's rule. Inclusion of the alpha-particle pre-equilibrium emission made use of the Milano group hypothesis on the preformed alpha-particle existence in the nucleus.

6. RESTRICTIONS OR LIMITATIONS

Only one particle induced reaction path can be treated with up to six sequentially emitted particles. Angular distributions of emitted particles and photons are not calculated. Constant energy mesh size and a single PE possibility are basic restrictions, too.

7. TYPICAL RUNNING TIME

Running time strongly depends on the composite system, excitation energy and the number of energy bins involved, number of channels, partial waves and pre-equilibrium emission model used. From few up to several tens of minutes. On a Dell pentium 100, the included test cases took <5 minutes.

8. COMPUTER HARDWARE REQUIREMENTS

The code can be operated on IBM PC or VAX computers.

9. COMPUTER SOFTWARE REQUIREMENTS

The MicroSoft-FORTRAN 77 Compiler v. 5.10 was used to create the PC executable under DOS 6.2. RSICC tested the code in a DOS window of Windows95. The NEADB tested on a VAX station 3100 under OpenVMS.

10. REFERENCES

M. Avrigeanu and V. Avrigeanu, "Development of a Computerized System for the Storage, Retrieval and Optimization of Optical Model Parameters for Nuclear Data Computations," NP-83-1994 (October 1994).

M. Avrigeanu and V. Avrigeanu, "Recent Improvements of the STAPRE-H95 Preequilibrium and Statistical Model Code," NP-86-1995 (September 1995).

M. Avrigeanu and V. Avrigeanu, "Energy-Dependent Single-Particle State Density Effects in the Hybrid Model of Pre-Equilibrium Nuclear Reactions," J. Phys., G:20, 613-635 (1994).

M. Ivascu, M. Avrigeanu, and V. Avrigeanu," Nuclear Structure Effects on Calculated Fast Neutron Reaction Cross Sections," Revue Roumaine de Physique, Tome 32, 2, 139-150 (1992).

V. Avrigeanu, P. E. Hodgson, and M. Avrigeanu, "Global Optical Potentials for Emitted Alpha Particles," Phys. Review C, 49, 2136-2141 (1994).

M. Avrigeanu and P. E. Hodgson, "Comparative Semi-Classical and Quantum-Mechanical Nucleon Pre-Equilibrium Emission Calculations," IC/92/31 (1992).

M. Avrigeanu and V. Avrigeanu, "Pre-Equilibrium Assumptions and Statistical Model Parameters Effects on Reaction Cross-Section Calculations," IC/92/32 (1992).

V. Avrigeanu and P. E. Hodgson, "Alpha-Particle Mean Field and Statistical Emission," Int. Conf. On Nuclear Data for Science and Technology, Gatlinburg, TN (9-13 May 1996).

M. Ivascu, V. Avrigeanu, M. Avrigeanu, "Nuclear Level Densities in the Mass Range 40< A <65," Rev. Roum. Phys., 32, 697-712 (1987).

11. CONTENTS OF CODE PACKAGE

Included in the package are the referenced documents and one 3.5-inch DS/HD diskette which includes the source files, PC executable file, test case input data and output in DOS format.

12. DATE OF ABSTRACT

April 1993, revised October 1997.