NESC0504 THRES2

1. NAME OR DESIGNATION OF PROGRAM:  THRES2

3. DESCRIPTION OF PROBLEM OR FUNCTION

THRES2 calculates neutron- induced reaction cross sections from 0 to 20 MeV and fission spectrum averages for nuclides having 21 to 82 protons. Reaction products considered are 2n, 3n, p, d, t, He-3, alpha, np, nd, nt, n-He3, n-alpha, pn, 2p, p-alpha, alpha-n, alpha-p, and dn.

4. METHOD OF SOLUTION

A statistical model with empirically determined parameters is employed. Binding energies, if calculated by the program, are calculated from an empirical mass formula due to Hillman (BNL-846). Since direct reaction effects can be important the calculations are normalized to compensate partly for deficiencies in the model. The empirical model is similar to previous (n,2n) work but is extended to include charged particle emission.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM:  Maximum of -, 19 reaction types

6. TYPICAL RUNNING TIME

Approximately 30 seconds per nuclide are required on a CDC6600 for the calculation of 19 reactions in the energy range 0 to 20 MeV in 0.5 MeV steps. Approximately 1 minute per nuclide is required for fission spectrum averages of the 19 reaction cross sections.

7. UNUSUAL FEATURES OF THE PROGRAM

Fitting parameters and binding energies are supplied by the program but may optionally be specified as input by the user. Output in the ENDF format is available. Uncertainties are estimated.

8. RELATED AND AUXILIARY PROGRAMS:  THRES2 replaces the earlier THRESH  program.

10. REFERENCES

- S. Pearlstein:
  Neutron-Induced Reactions in Medium Mass Nuclei
  Journal of Nuclear Energy, Vol. 27, pp. 81-99 (1973).
- S. Pearlstein:
Analysis of (n,2n) Cross Sections for Medium and Heavy Mass Nuclei    Nuclear Science and Engineering, Vol. 23, pp. 238-250 (1965).
- S. Pearlstein:
  Neutron Cross Sections and their Uncertainties Obtained from
  Nuclear Systematics
  NBS Special Publication 425, pp. 332-334 (1975).

- S. Pearlstein:
  Program THRES2 (December 1975)

11. MACHINE REQUIREMENTS:  The program uses 13K (decimal) on the CDC6600.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  SCOPE (CDC6600),  OS/360 (IBM360).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

     A
PDP10 version of THRES2 has been prepared and used at BNL also.

15. NAME AND ESTABLISHMENT OF AUTHORS

   6600          S. Pearlstein
                 National Nuclear Data Center
                 Brookhaven National Laboratory
                 Upton, Long Island, New York  11973
   360           L. Garcia de Viedma
                 NEA Data Bank
                 B. P. No. 9
                 91190 Gif-sur-Yvette, France

File name	File description	Records
NESC0504_01.001	SOURCE FORTRAN IV EBCDIC	1250
NESC0504_01.002	JCL FOR RUNNING SAMPLE PROBLEM	23
NESC0504_01.003	SAMPLE PROBLEM 1 INPUT	3
NESC0504_01.004	SAMPLE PROBLEM 2 INPUT	8
NESC0504_01.005	SAMPLE PROBLEM 1 OUTPUT	50
NESC0504_01.006	SAMPLE PROBLEM 2 OUTPUT	298