1. NAME AND TITLE

ERINNI: Optical Model Calculation of Multiple Cascading Particle Emissions.

2. CONTRIBUTOR

Centro di Calcolo del CNEN, Bologna, Italy, through the NEA Data Bank, Gif-sur-Yvette, France.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 360/370.

4. NATURE OF PROBLEM SOLVED

ERINNI offers an optical model calculation of multiple cascading particle emissions. It computes 42 cross sections for each incident energy representing all possible compound nucleus processes of types (x,a), (x,ab), and (x,abc) where x can be indifferently a neutron, proton, or alpha particle; a and b can be a neutron, a proton, an alpha or gamma particle; and c can be a neutron or a gamma particle. ERINNI is particularly useful for extensive cross section calculations such as those in the range of reactor calculation needs.

5. METHOD OF SOLUTION

The scattering amplitudes and the other optical model quantities are calculated in accordance with spherical local potentials by the usual methods.

Parameters are needed for 10 residual nuclei, hence particular care was devoted to reducing the input procedure. The table for pairing energies, the Mass excess table, the level density data systematics, and the optical model parameter sets most frequently used in literature are all incorporated in the program and can be used optionally as an alternative to more specific choices of data.

6. RESTRICTIONS OR LIMITATIONS

No width fluctuation is included because it is devised for high energy calculations.

7. TYPICAL RUNNING TIME

The OECD NEA Data Bank executed the test case included in the package on an IBM 3084Q computer in 375 seconds of CPU time. Computing time was reduced because the various optical model transmission coefficients and consequent decay probabilities at a given incident energy, when they are calculated within appropriately narrow energy intervals, lend themselves to interpolation.

8. COMPUTER HARDWARE REQUIREMENTS

ERINNI is operable on the IBM 360/370 computers. 240 kbytes of fast core memory is required if used together with the overlay structure.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

10. REFERENCE

F. Fabbri and G. Reffo, "ERINNI: An Optical Model Fortran IV Code for the Calculation of Multiple Cascading Particle Emissions," RT/FI(77)4 (April 1977).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (360KB) DOS diskette which contains the source code and sample problem input.

12. DATE OF ABSTRACT

June 1986.