**1. NAME AND TITLE**

OGRE: A General-Purpose Monte Carlo Gamma-Ray Transport Code System.

**PROTOTYPES**

GRE-P1: Transmission Through Laminated Slabs--Sample Calculation

OGRE-G: Calculation of Dose Rates at Arbitrary Points in an Arbitrary Geometry

**AUXILIARY ROUTINES**

XSECT: Cross Section Handling Code and Library.

OGRE originated in 1965 and has been maintained since in RSIC. In its 16 year history, RSIC has distributed it 110 times.

**2. CONTRIBUTOR**

Engineering Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN IV; IBM 360/370 series.

**4. NATURE OF PROBLEM SOLVED**

The OGRE code system was designed to calculate, by Monte Carlo methods, any quantity related to gamma-ray transport. The system is represented by two examples: OGRE-P1 and OGRE-G. The OGRE-P1 code is a simple prototype which calculates dose rate on one side of a slab due to a plane source on the other side. The OGRE-G code, a prototype of a code utilizing a general-geometry routine, calculates dose rate at arbitrary points. A very general source description in OGRE-G may be employed by reading a tape prepared by the user.

**5. METHOD OF SOLUTION**

Case histories of gamma rays in the prescribed geometry are generated and analyzed to produce averages of any desired quantity which, in the case of the prototypes, are gamma-ray dose rates. The system is designed to achieve generality by ease of modification. No importance sampling is built into the prototypes.

A very general geometry subroutine permits the treatment of complicated geometries. This is essentially the same routine used in the O5R (CCC-17) neutron transport system. Boundaries may be either planes or quadric surfaces, arbitrarily oriented and intersecting in arbitrary fashion.

Cross section data is prepared by the auxiliary master cross section code XSECT which may be used to originate, update, or edit the master cross section tape. The master cross section tape is utilized in the OGRE codes to produce detailed tables of macroscopic cross sections which are used during the Monte Carlo calculations.

**6. RESTRICTIONS OR LIMITATIONS**

Maximum cross-section array information may be estimated by a given formula for a specific problem. The number of region must be _ 50.

**7. TYPICAL RUNNING TIME**

Running time varies with the type of problem.

**8. COMPUTER HARDWARE REQUIREMENTS**

Standard equipment is used. Two tape units are needed for the IBM 360/370, plus the on-line card reader.

**9. COMPUTER SOFTWARE REQUIREMENTS**

OGRE is almost entirely written in FORTRAN; uses FORTRAN IV, Level H, IBM 360/370, Monitor System.

**10. REFERENCES**

** a: Included in documentation:**

S. K. Penny, D. K. Trubey, and M. B. Emmett, "OGRE, a Monte Carlo System for Gamma-Ray Transport Studies, Including an Example (OGRE-P1) for Transmission Through Laminated Slabs," ORNL-3805 (April 1966).

D. K. Trubey, "PRINT-SIG, An OGRE Routine to Print Gamma-Ray Total Cross Sections and Energy Deposition Coefficients," ORNL-TM-3048 (October 1968).

D. K. Trubey and H. E. Francis, "OGRE MASTAPE - Photon Interaction Cross Section Library and Data Handling Code," ORNL-TM-3046 (July 1969).

D. K. Trubey, S. K. Penny, and M. B. Emmett, "OGRE-P2, A Monte Carlo Program for Computing Gamma-Ray Leakage from Laminated Slabs with a Distributed Source," ORNL-TM-237 (August 1962).

D. K. Trubey and J. R. Stockton, "OGRE Cross Section Package for Using Photon Interaction Data in ENDF/B Format," ORNL-TM-2757 (October 1969).

**b: Background information:**

D. K. Trubey and M. B. Emmett, "OGRE-G, an OGRE System Monte Carlo Code for the Calculation of Gamma-Ray Dose Rate at Arbitrary Points in an Arbitrary Geometry," ORNL-TM-1212 (January 1966).

**11. CONTENTS OF CODE PACKAGE**

The package contains the referenced documents, sample data sheets, and one (1.2MB) DOS diskette on which is written--in separate files-- the source card decks for the prototypes and the auxiliary routine, and input and output for sample problems, including a library of cross sections.

**12. DATE OF ABSTRACT**

July 1967; updated July 1981, October 1991.

**KEYWORDS: ** MONTE CARLO; GAMMA-RAY; SLAB; COMPLEX GEOMETRY