1. NAME AND TITLE

PREANG: Calculation of Pre-equilibrium Angular Distributions with the Exciton Model.

PREANG is a modified version of PREEQ and PREEQ-ECN.

2. CONTRIBUTOR

Netherlands Energy Research Foundation, Energy Center of The Netherlands, Petten (NH), The Netherlands.

3. CODING LANGUAGE AND COMPUTER

Fortran; CDC CYBER 175.

4. NATURE OF PROBLEM SOLVED

PREANG calculates cross sections, particle emission spectra and their angular distributions for reactions of type A(x,y)B where x and y can be n, p, alpha, He-3, d or t.

5. METHOD OF SOLUTION

PREANG is based upon the time-integrated master-equation approach of the exciton model. It first determines the transition and emission rates and the level densities and stores them in the memory. Next, it calculates the desired cross sections; these contain precompound and compound contributions. The angular distributions are calculated according to the model of G. Mantzouranis, D. Agassi and H. A. Weidenmuller.

6. RESTRICTIONS OR LIMITATIONS

The validity of the model is restricted to projectile energies of 10 to 50 MeV. Only first-particle emission cross sections are calculated. The level densities are assumed to be described by continuum distributions; PREANG accounts for no spin and parity dependences.

7. TYPICAL RUNNING TIME

On the CDC CYBER 175 computer, PREANG usually executes in less than 2 seconds.

8. COMPUTER HARDWARE REQUIREMENTS

PREANG is operable on the CDC CYBER 175 computers. It requires less than 60,000 words (octal) of storage.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran compiler is required.

10. REFERENCES

a. Included in the documentation:

J. M. Akkermans and H. Gruppelaar, "Calculation of Pre-equilibrium Angular Distributions with the Exciton Model Code PREANG," ECN-60 (May 1979).

b. Background information:

G. Mantzouranis, D. Agassi, and H. A. Weidenmuller, Phys. Lett. 57B (1975) 220.

11. CONTENTS OF CODE PACKAGE

Included are the referenced document (10.a) and one (1.2MB) DOS diskette which contains the source code and sample problem input.

12. DATE OF ABSTRACT

April 1984.