IAEA0971 STAPRE-H95.

1. NAME OR DESIGNATION OF PROGRAM:  STAPRE-H95.

3. NATURE OF PHYSICAL 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.

4. 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.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

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 single PE  possibility are basic restrictions, too.

6. TYPICAL RUNNING TIME

The calculation of the excitation function for a typical neutron induced activation reaction, with 1 MeV step up to the incident energy of 20 MeV (original STAPRE sample case, with an  energy bin size of 0.5 MeV) takes 23 seconds on PC 486/DX2(66MHz) by using the PE exciton model. Use of generalized GDH model requires 174 seconds on PC 486/DX2, 764 seconds on MicroVAX 3100, and 145 seconds on the VAX-Cluster of the Oxford University PNL (calculation for 14.8 MeV incident energy and 0.3 MeV bin size -present sample case 1- requires 39, 158 and 30 seconds respectively).

NEA-DB ran the three test cases included in this package on: (1) VAXStation 3100 M38; (2) PC/P75. Execution times varied between 25sec and 2min on (1); and between 6sec and 20sec on  (2).

7. UNUSUAL FEATURES OF THE PROGRAM

The generalized GDH model including alpha-particle emission and angular momentum and parity conservation allows consistent PE and Hauser-Feshbach model calculation, of particular interest for the isomeric state populations and production cross sections for gamma rays from low excited levels. The same or different optical potential can be used in both the GDH  and Hauser-Feshbach calculations, as well as to provide the GDH intranuclear transition rates. Energy-dependent single-particle state densities, different for excited particles and holes, are used within particle-hole state densities which includes also advanced pairing and shell-effects corrections.

8. RELATED AND AUXILIARY PROGRAMS

STAPRE-H95 is an extended version of the original code STAPRE (M.Uhl), and includes also the optical model code SCAT2 (O.Bersillon) with enlarged optical potential basis  and the possibility to handle parameter sets of volume integrals of  the real and imaginary potentials. The subroutine HYBRID (M.Blann) was the origin of the generalized GDH model. Energy-dependent single-particle state densities and full geometry-dependent hybrid model description of the alpha-particle PE are used in addition to the previous version available through NEA-DB.

10. REFERENCES

- M. Uhl and B. Strohmaier:
  STAPRE
  IRK-Vienna Report IRK-76/01 )1976, Upd. 1978)
- M. Blann:
  Rochester University Report COO-3494-10 (1973)
- O. Bersillon:
  SCAT2
  CE Bruyeres-le-Chatel CEA-N-2227 (1981)
- M. Avrigeanu, M. Ivascu and V. Avrigeanu:
  IPNE-Bucharest Report NP-63-1987 (Upd. 1988)
- M. Avrigeanu, V. Avrigeanu, G. Cata, M. Ivascu:
  Revue Roumaine de Physique 32, 837 (1987)
- M. Avrigeanu, V. Avrigeanu and M. Ivascu:
  Z. Phys. A329, 177 (1988); A335, 229 (1990)
- M. Avrigeanu, P.E. Hodgson and A.J. Koning:
  J.Phys. G:19, 745 (1993)
- M. Avrigeanu et al.:
  J.Phys. G:21, 837 (1995)
- M. Avrigeanu, A. Harangozo and V. Avrigeanu:
  IPNE-Bucharest Report NP-85-1995 (1995)

- M. Avrigeanu and V. Avrigeanu:
  Development of a Computerized System for the storage, Retrieval
  and Optimization of Optical Model Parameters for Nuclear Data
  Computations
  IPNE-Bucharest Report No. NP-83-1994 (October 1994)
- M. Avrigeanu and V. Avrigeanu:
  Recent improvements of the STAPRE-H95 Preequilibrium and
  Statistical Model Code
  IPNE-Bucharest Report No. NP-86-1995 (September 1995)
- M. Avrigeany 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 37 no.2 139-150 (1992)
- M. Ivascu, M. Avrigeanu and V. Avrigeanu:
  Nuclear Level Densities in the Mass Range
  Revue Roumaine de Physique, Tome 32 no.7 697-712 (1992)
- V. Avrigeanu, P.E. Hodgson and M. Avrigeanu:
  Global Optical Potentials for Emitted Alpha Particles
  Physical Review C, Vol.49, no.4 2136-2141 (1994)
- V. Avrigeanu, P.E. Hodgson and M. Avrigeanu:
  Int. Conf. on Nuclear Data for Science and Technology,
  9-13 May, 1994, Gatlinburg, Tennessee pp 496-498
- M. Avrigeanu and P.E. Hodgson:
  Comparative Semi-Classical and Quantum-Mechanical Nucleon Pre
  Equilibrium Emission Calculations
  ICTP- IC/92/31 (1992)
- M. Avrigeanu and V. Avrigeanu:
  Pre-Equilibrium Assumptions and Statistical Model Parameters
  Effects on Reaction Cross-Section Calculations
  ICTP- IC/92/32 (1992)

11. MACHINE REQUIREMENTS

The MS-FORTRAN 77 Compiler v. 3.31 and Linker  v. 3.04 generate an executable load module of about 800KB, with a
packed version of about 432 KB and a minimum load size of about 578KB. Two permanent files and eight local files require about 530KB.

The program has been implemented by NEA-DB both on a
VAXStation 3100 M38; and a PC Brett Pentium 75 with 75MHz and 16 MB  of RAM.

13. OPERATING SYSTEM OR MONITOR UNDER WHICH PROGRAM IS EXECUTED:  PC DOS 3.2.

OpenVMS 6.1 for VAXStation 3100; MS-DOS 6.2 with compiler MS FORTRAN 5.10 for PC/P75.

14. ANY OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

Optimum operation on PC/AT requires a system configuration with a
virtual disk of at least 500 KB for 10 local files used by the code, and a math co-processor.

15. NAME AND ESTABLISHMENT OF AUTHOR

          M. Avrigeanu, V.Avrigeanu
          Institute of Physics and Nuclear Engineering
          P.O. Box MG-6
          76900 Bucharest, Romania

File name	File description	Records
IAEA0971_03.001	Information file	146
IAEA0971_03.002	Source program segment for PC	2168
IAEA0971_03.003	Source program segment for VAX	2168
IAEA0971_03.004	Source program segment	1224
IAEA0971_03.005	Source program segment	1247
IAEA0971_03.006	Source program segment	1337
IAEA0971_03.007	Source program segment	822
IAEA0971_03.008	Source program segment	888
IAEA0971_03.009	Source program segment	1561
IAEA0971_03.010	Source program segment	1663
IAEA0971_03.011	Source program segment	1203
IAEA0971_03.012	Executable file for PC	0
IAEA0971_03.013	User's Manual	555
IAEA0971_03.014	Batch file to compile, link and run on PC	8
IAEA0971_03.015	MS utility NMAKE description file for update	36
IAEA0971_03.016	JCL to compile, link and run on VAX	17
IAEA0971_03.017	Sample input for case 1	277
IAEA0971_03.018	Sample input for case 2	194
IAEA0971_03.019	Sample input for case 3	245
IAEA0971_03.020	Sample output (PC) for case 1	1066
IAEA0971_03.021	Sample output (PC) for case 2	563
IAEA0971_03.022	Sample output (PC) for case 3	1188
IAEA0971_03.023	Sample output (VAX) for case 1	1065
IAEA0971_03.024	Sample output (VAX) for case 2	562
IAEA0971_03.025	Sample output (VAX) for case 3	1179
IAEA0971_03.026	DOS file-names	25