RSIC COMPUTER CODE PSR-049

1. NAME AND TITLE

DINT: Multigroup Coherent-Incoherent Cross Section Data Generator for Photon Transport Calculations.

2. CONTRIBUTOR

Sandia National Laboratory, Albuquerque, New Mexico.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; CDC 6600 (A), IBM 360/370 (B).

4. NATURE OF PROBLEM SOLVED

DINT prepares multigroup cross-section tables which are based upon the physics of coherent-incoherent photon scattering.

5. METHOD OF SOLUTION

Using raw cross section data which are an integral part of DINT, the necessary averaging integrals are performed to calculate group-averaged absorption and scattering cross sections for use in discrete ordinates photon transport calculations. The absorption mechanisms considered are the photoelectric effect and, when appropriate, pair production.

The scattering mechanism is taken to be the sum of effects due to coherent and incoherent scattering interactions. This description of photon scattering includes the effects of atomic electron binding.

Gauss-Legendre and standard adaptive numerical integration techniques are used to evaluate the single and double integrals that arise in the definitions of the scattering table entries.

6. RESTRICTIONS OR LIMITATIONS

Generally speaking, in any cross section production run, the maximum allowed complexity is the generation of P₀ - P₈ cross section tables for 20 elements with 50 energy groups. These restrictions are due to the sizes of dimensioned arrays. Cross sections for any element with atomic number in the range from 1 to 100 can be calculated.

7. TYPICAL RUNNING TIME

Running times are very problem-dependent. On the CDC 6600, the time required to produce P₂-approximation cross sections with 18 energy groups for 4 elements is about 6 minutes.

8. COMPUTER HARDWARE REQUIREMENTS

DINT was designed to run on the CDC 6600 computer (A) and is also operable on the IBM 360/370 computers.

On the CDC 6600 computer, DINT uses Extended Core Storage (ECS). However, ECS is used only as a fast random access storage device during reordering of the cross sections for the "storage minimization" output mode. On other types of machines, disc storage could be used to replace ECS. Two files are needed in addition to input and output: one for the raw cross section data, the other for the group-averaged tables. 40,000 words of core memory are required.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required. DINT runs under the CDC Scope 3.3 system on the CDC 6600.

10. REFERENCE

K. G. Adams, F. Biggs, and J. H. Renken, "DINT: A Computer Program Which Prepares Multigroup Coherent-Incoherent Cross Sections for Photon Transport Calculations," SC-RR-72 0684 (December 1972).

11. CONTENTS OF CODE PACKAGE

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

12. DATE OF ABSTRACT

January 1984.