**1. NAME AND TITLE**

MORSE-CG: A General Purpose Monte Carlo Multigroup Neutron and Gamma- Ray Transport Code System with Combinatorial Geometry. We recommend C00474/ALLCP/02 MORSE-CGA.

**AUXILIARY ROUTINES**

PICTURE: Geometry Input Diagnostic Code.

DOMINO: General Purpose Discrete Ordinates-to-Monte Carlo Coupling Code for Radiation Transport (for use with DOT 3.5).

DOMINO II: As above, but for use with DOT 4.

MORSE was originally programmed at the Oak Ridge National Laboratory
(ORNL) for the CDC 1604 computer (CCC-127; 1970) and was later modified and
extended for the IBM 360 computer. The original version incorporated the CCC-17/O5R
generalized geometry routines. The Mathematical Applications Group, Inc. (MAGI)
combinatorial geometry (CG) routines were implemented in a new ORNL version which
was denoted CCC-203/MORSE-CG. The latest in this series is a version with array
geometry capabilities, CCC-474/MORSE-CGA. **We strongly urge new users to obtain
that version.**

**2. CONTRIBUTORS**

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

Science Applications, Inc., Huntsville, Alabama, and Albuquerque, New Mexico.

University of Wisconsin, Stoughton.

Mathematical Applications Group, Inc., Elmsford, New York.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN IV and Assembler language; UNIVAC 1108 and 1100/60 (C00203U000000), CDC 6600 and Cyber 176 (C00203CY00000), IBM 3033 (C00203I036000), VAX (C00203D0VAX00), CRAY (C00203C000000).

**4. NATURE OF PROBLEM SOLVED**

The MORSE code is a multipurpose neutron and gamma-ray transport Monte Carlo code. It has been designed as a tool for solving most shielding problems. Through the use of multigroup cross sections, the solution of neutron, gamma-ray, or coupled neutron-gamma-ray problems may be obtained in either the forward or adjoint mode. Time dependence for both shielding and criticality problems is provided. General three-dimensional geometry may be used with an albedo option available at any material surface. Isotropic or anisotropic scattering up to a P16 expansion of the angular distribution is allowed.

**5. METHOD OF SOLUTION**

Monte Carlo methods are used to solve the forward and the adjoint transport equations. Quantities of interest are then obtained by summing the contributions over all collisions, and frequently over most of phase space.

Standard multigroup cross sections, such as those used in discrete ordinates codes, may be used as input; either CCC-254/ANISN, CCC-42/DTF-IV, or CCC-89/DOT cross section formats are acceptable. Both fixed and free format are acceptable. Anisotropic scattering is treated for each group-to-group transfer by utilizing a generalized Gaussian quadrature technique.

The MORSE code is organized into functional modules with simplified interfaces such that new modules may be incorporated with reasonable ease. The modules are (1) random walk, (2) cross section, (3) geometry, (4) analysis, and (5) diagnostic.

While the basic MORSE code assumes the analysis module is user-written, a general analysis package, SAMBO, is included. SAMBO handles some of the drudgery associated with the analysis of random walks and minimizes the amount of user-written coding. An arbitrary number of detectors, energy-dependent response functions, energy bins, time bins, and angle bins are allowed. Analysis is divided for each detector as follows: uncollided and total response, fluence versus energy, time-dependent response, fluence versus time and energy, and fluence versus angle and energy. Each of these quantities is listed as output. The diagnostic module provides an easy means of printing out, in useful form, the information in the various labelled commons and any part of blank COMMON. The module is very useful to debug a problem and to gain further insight into the physics of the random walk.

**6. RESTRICTIONS OR LIMITATIONS**

Flexible dimensioning techniques require the use of a large container array in blank COMMON.

**7. TYPICAL RUNNING TIME**

Sample problem #1 ran in .28 min on the IBM 3033, .1 min on the CRAY and .23 min on the CYBER 176.

The PICTURE sample problem ran in less than 2 seconds on the IBM 3033.

**8. COMPUTER HARDWARE REQUIREMENTS**

The code requires computers with standard I-O plus one direct access storage device. PICTURE uses approximately 100 K of core storage (including system library routines). MORSE-CG uses about 200 K storage (including system library routines) on the IBM 3033 plus 4*(blank COMMON size)/1000.

**9. COMPUTER SOFTWARE REQUIREMENTS**

Standard software for each of the versions may be used. Any nonstandard library routines which were used have been included in the code package or a full description is given for the user's information.

**10. REFERENCES**

M. B. Emmett, "The MORSE Monte Carlo Radiation Transport Code System,"ORNL-4972 (February 1975); ORNL-4972/R1 (February 1983); ORNL 4972/R2 (July 1984). [Output for the 9 sample problems described in ORNL-4972/R2 is provided on microfiche].

S. N. Cramer, "pplications Guide to the MORSE Monte Carlo Code" ORNL/TM-9355 (August 1985).

M. B. Emmett, "DOMINO-II, A General Purpose Code for Coupling DOT-IV Discrete Ordinates and Monte Carlo Radiation Transport Calculations," ORNL/TM-7771 (May 1981) plus excerpts from ORNL-4853, "DOM INO, A General Purpose Code for Coupling Discrete Ordinates and Monte Carlo Radiation Transport Calculations," by M. B. Emmett, C. E. Burgart, and T. J. Hoffman (July 1973).

E. A. Straker and M. B. Emmett, "Collision Site Plotting Routines and Collision Density Fluence Estimates for the MORSE Monte Carlo Code," ORNL-TM-3585 (October 1971) plus informal notes.

J. S. Tang, P. N. Stevens, and T. J. Hoffman, "Monte Carlo Biasing Using Two-Dimensional Discrete Ordinates Adjoint Flux," ORNL/TM-5414 (June 1976).

J. Kinch, "MORSE Routines for the UNIVAC 1108," Informal Notes (June 1975).

M. B. Emmett, "BIASPREP Input-MORSE Version," Informal Notes.

S. Goetsch, "Documentation for MORSE-CG VAX 11/780 VMS Version," Informal Notes (December 1983).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced documents and one DS/HD 3.5-in. (1.44 MB) diskette in self-extracting compressed DOS files which contain source programs, special routines, and sample problem input, plus output from the original sample problem written in list format.

**12. DATE OF ABSTRACT**

May 1975; updated October 1983, January 1984, March 1984, October 1984, May 1985, September 1985, March 1987, June 1990.

**KEYWORDS: ** MONTE CARLO; NEUTRON; GAMMA-RAY; MULTIGROUP;
COMPLEX GEOMETRY; COMBINATORIAL GEOMETRY;
ADJOINT