**1. NAME AND TITLE**

PAPIN: A Code System to Calculate Cross Section Probability Tables, Bondarenko and
Transmission Self-Shielding Factors for Fertile Isotopes in the Unresolved
Resonance Region.

**2. CONTRIBUTOR**

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

**3. CODING LANGUAGE AND COMPUTER**

Fortran IV; IBM 370.

**4. NATURE OF PROBLEM SOLVED**

PAPIN calculates cross section probability tables, Bondarenko self-shielding factors and average
self-indication ratios for non-fissile isotopes, below the inelastic threshold, on the basis of the ENDF/B
prescriptions for the unresolved resonance region.

**5. METHOD OF SOLUTION**

Monte Carlo methods are utilized to generate ladders of resonance parameters in the unresolved resonance region from average resonance parameters and their appropriate distribution functions.

The neutron cross sections are calculated by the single level Breit-Wigner (SLBW) formalism with s, p and d-wave contributions. The cross section probability tables are constructed by sampling the Doppler-broadened cross sections.

The various self-shielded factors are computed numerically as Lebesgue integrals over the cross
section probability tables.

**6. RESTRICTIONS OR LIMITATIONS**

None noted.

**7. TYPICAL RUNNING TIME**

No study has been made by RSIC of typical running times for PAPIN.

**8. COMPUTER HARDWARE REQUIREMENTS**

PAPIN is operable on the IBM 370 computers.

**9. COMPUTER SOFTWARE REQUIREMENTS**

A Fortran IV compiler is required.

**10. REFERENCE**

J. G. Munoz-Cobos, "PAPIN: A Fortran-IV Program to Calculate Cross Section Probability
Tables, Bondarenko and Transmission Self-Shielding Factors for Fertile Isotopes in the Unresolved
Resonance Region," ORNL-TM-7883 (ENDF-310) (August 1981).

**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**

April 1984.

**KEYWORDS: ** ENDF FORMAT; MULTIGROUP CROSS SECTION PROCESSING;
NEUTRON CROSS SECTION PROCESSING; NUCLEAR MODELS