**1. NAME AND TITLE**

SUPERTOG-LTT: A Modification of PSR-13/SUPERTOG-III Applied to Libraries with
Tabulated Elastic Scattering and Anistropy Densities.

**2. CONTRIBUTOR**

Institute of Nuclear Power, Bulgarian Academy of Sciences, Sofia, Bulgaria.

**3. CODING LANGUAGE AND COMPUTER**

Fortran IV; IBM 360.

**4. NATURE OF THE PROBLEM SOLVED**

In calculating the matrix for intergroup elastic-scattering transitions using SUPERTOG programs,
it is necessary that the data on the anisotropy of the elastic scattering be given in terms of the
coefficients for a Legendre polynomial expansion of the density function. However, for all the
material in the ENDL library and for some of the material in ENDF/B-IV, the information on the
scattering anisotropy is given in the form of tabulated values of the actual density function. Existing
versions of the SUPERTOG program cannot be used for these materials.

**5. METHOD OF SOLUTION**

SUPERTOG-LTT is a modification of PSR-13/SUPERTOG-III which enables us to calculate the
elastic-scattering matrix in either of the two ways the anistropy may be given. With this method,
which is based on an approximation by means of orthonormal polynomials, it is possible to calculate
the coefficients in the Legendre polynomial expansion of the density function during the operation of
the actual program. In fact, this procedure takes less than 15% of the total running time of the
SUPERTOG programs.

**6. RESTRICTIONS OR LIMITATIONS**

In accordance with the requirements of the algorithms followed in SUPERTOG-III, the order of
the Legendre polynomial expansion of the function p(mu,E) should not exceed 30 (not more than 31
coefficients, including the zeroth).

**7. TYPICAL RUNNING TIME**

No study has been made by RSIC of typical running times for SUPERTOG-LTT.

**8. COMPUTER HARDWARE REQUIREMENTS**

SUPERTOG-LTT was processed on an IBM 3033 computer at Oak Ridge National Laboratory.

**9. COMPUTER SOFTWARE REQUIREMENTS**

A Fortran IV compiler is required.

**10. REFERENCE**

G. Bojkov, V. Gadzhokov, K. Ilieva, "Modification of the SUPERTOG Program Applied to
Libraries with Tabulated Elastic-Scattering Anisotropy Densities," INDC-6/GV (February 1982).

**11. CONTENTS OF CODE PACKAGE**

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

**12. DATE OF ABSTRACT**

January 1986.

**KEYWORD: ** ENDF FORMAT