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.

**KEYWORDS: ** GAMMA-RAY CROSS SECTION PROCESSING; MICROCOMPUTER;
NUCLEAR MODELS; PARAMETRIC MODELS