STAPREF, Nuclear Reactions Cross-Sections by Evaporation Model, Gamma-Cascades

1 - Nature of physical problem solved: Calculation of energy-averaged cross sections for nuclear reactions with emission of particles and gamma rays and fission. The models employed are the evaporation model with inclusion of pre-equilibrium decay and a gamma-ray cascade model. Angular momentum and parity conservation are accounted for. Major improvement in the original 1976 STAPRE program by M. Uhl relates to level density approach, implemented in subroutine ZSTDE. Generalized superfluid model is incorporated, Boltzmann-gas modeling of intrinsic state density and semi-empirical modeling of a few-quasiparticle effects in total level density at equilibrium and saddle deformations of actinide nuclei. 2 - Method of solution: Integrations in connection with the evaporation formulas are approximated by summation over energy bins. For the gamma-ray cascades a recursion formula is employed. The width-fluctuation correction factor is calculated by use of Simpson's rule. 3 - Restrictions on the complexity of the problem: Only particle induced reactions can be treated. The number of sequentially emitted particles is limited to 6, while the number of gamma rays is arbitrary. Angular distributions of emitted particles and photons are not calculated. STAPREF: The number of sequentially emitted particles could be easily extended up to, say, 30 by increasing the array dimensions to cover incident particle energy range up to 150 MeV