**1. NAME AND TITLE**

MORSE-L: Multigroup Neutron and Gamma-Ray Transport Code System for the Solution of Penetration Problems. We recommend C00474/ALLCP/02 MORSE-CGA.

MORSE-L was adapted from the original Oak Ridge National Laboratory version of the MORSE and SAMBO codes (CCC-127) but is restricted to penetration problems only.

**2. CONTRIBUTORS**

E. O. Lawrence Livermore Laboratory, Livermore, California (A).

EG&G, Santa Barbara Division, Goleta, California (B).

**3. CODING LANGUAGE AND COMPUTER**

CHAT, CDC 6600 (A); FORTRAN IV, CDC 6600 (B).

**4. NATURE OF PROBLEM SOLVED**

MORSE-L is a Monte Carlo multigroup transport code designed to solve neutron, gamma and coupled neutron-gamma penetration problems in either the forward or adjoint mode. Time-dependence of the calculated fluence is provided and results may also be obtained for energy and angular dependence. Geometrical descriptions may be made using either a one-dimensional spherical model or a generalized three-dimensional model utilizing quadratic surfaces as the interface between adjoining material media. Anisotropic scattering is provided. Several albedo materials may be used within the same problem.

**5. METHOD OF SOLUTION**

Monte Carlo techniques are used to solve the usual multigroup form of the Boltzmann transport equation. Survival weighting is employed in all cases and splitting and Russian roulette may be used. The exponential transform, with path stretching away from or towards a given point, is available on option. Fluence and/or current results are obtained from the random walk by using estimators based upon reaction, predicted reaction, path length, boundary crossing, and point techniques. For the point estimator, an analytic model may be used to describe Compton scattering of gamma rays. Printed results include the standard deviation of the quantity printed while total integrated responses also include batch results and a W-Test parameter. Most of the problem input is provided on cards using a special free form format designed for this code. Cross sections, and related data, may be read from cards and/or a library tape (or disk file). Problem output is provided on the usual printed page, on punched cards, and on pictures drawn by using the standard LLL DD80 routines. Disk files are used to store temporary data during problem setup.

**6. RESTRICTIONS OR LIMITATIONS**

None noted.

**7. TYPICAL RUNNING TIME**

Running time can range from minutes to hours, depending on the problem.

**8. COMPUTER HARDWARE REQUIREMENTS**

MORSE-L was written originally for the CDC 6600 but is also operational on the CDC 6400/7600 by assigning blank common to LCM storage. DD80 CRT plotting is required in the original version but may be converted to available plotting hardware.

**9. COMPUTER SOFTWARE REQUIREMENTS**

MORSE-L was written in CHAT for a Lawrence Livermore Laboratory internal compiler, LRLTRAN, and was converted to run on a standard FORTRAN IV compiler (B).

**10. REFERENCES**

T. P. Wilcox, "MORSE-L, A Special Version of the MORSE Program Designed to Solve Neutron, Gamma and Coupled Neutron-Gamma Penetration Problems," UCID-16680 (September 1972).

T. P. Wilcox, "Does MORSE-L Really Work?," UCID-16682 (September 1972).

T. P. Wilcox, "MORSE Cross Section Library Tapes," UCID-16683 (July 1973).

**12. DATE OF ABSTRACT**

September 1975.

**KEYWORDS:** MONTE CARLO; NEUTRON; GAMMA-RAY; ADJOINT; TIME-DEPENDENT; ONE-DIMENSION; SPHERICAL GEOMETRY; COMPLEX
GEOMETRY