1. NAME AND TITLE

LPSC: Proton Penetration Code - Multilayer Slab Geometry.

AUXILIARY ROUTINE

TAPFIX: Data Generator.

This package is retained by RSIC to preserve space technology developed in the 1960s.

2. CONTRIBUTOR

NASA Lewis Research Center, Cleveland, Ohio.

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV; IBM 7090 and 7094.

4. NATURE OF PROBLEM SOLVED

LPSC calculates particle spectra and dose behind multilayer, infinite slabs for any given energy spectrum of protons impinging normally on the shield. Incident primary protons are considered, as well as the following types of secondary radiation: cascade protons, cascade neutrons, and evaporation neutrons.

5. METHOD OF SOLUTION

The straight-ahead approximation technique is used in treating the high-energy "cascade" particles produced from nonelastic nuclear collisionsthat is, it is assumed that when a nonelastic collision occurs, the high-energy secondary particles are emitted in the direction of the incident particle. The code assumes that the low-energy "evaporation" secondary neutrons from nonelastic nuclear collisions are emitted isotropically and takes into account this angular dependence. Data developed by Bertini (see References) is employed for particle production from high-energy nonelastic collisions.

Spectra and doses are calculated inside the shield and at intermediate thicknesses through the shield.

6. RESTRICTIONS OR LIMITATIONS

The approximation is assumed to be valid for protons with energies > 100 MeV.

7. TYPICAL RUNNING TIME

No studies have been made to determine typical running time. Estimated running time for the sample problem on the IBM 7090: TAPFIX - .01 hour; LPSC - .09 hour.

8. COMPUTER HARDWARE REQUIREMENTS

The code was designed for the IBM 7094 and is also operable on the IBM 7090.

A 32,768 core memory and a maximum of 5 tape units are required.

9. COMPUTER SOFTWARE REQUIREMENTS

The codes are operable in the FORTRAN IV IBJOB Monitor System.

The TAPFIX code is processed first to generate a library (binary) tape to be used as an input tape for LPSC.

10. REFERENCES

R. I. Hildebrand and H. E. Renkel, "The Lewis Proton Shielding Code", NASA TM X-52166 (1966).

H. W. Bertini, "Low Energy Intranuclear Cascade Calculations," Phys. Rev., 131:1801 (1963).

11. CONTENTS OF CODE PACKAGE

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

12. DATE OF ABSTRACT

January 1968; updated July 1981, February 1985.