**1. NAME AND TITLE**

SPACETRAN: Dose Calculations at Detectors at Various Distances from the Surface of
a Cylinder.

SPACETRAN I and II were packaged 8/11/69; SPACETRAN III was added 8/30/73. Each is
complementary: I -- integration of ANISN leakage data, II -- assumed powers of cosine angular
distribution, and III -- integration of DOT III scalar flux data.

**2. CONTRIBUTOR**

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

**3. CODING LANGUAGE AND COMPUTER**

Fortran IV; IBM 360/75/91.

**4. NATURE OF PROBLEM SOLVED**

SPACETRAN is designed to calculate the energy-dependent total flux, or some proportional
quantity such as kerma, due to the radiation leakage from the surface of a right-circular cylinder at
detector positions located arbitrary distances from the surface. The assumptions are made that the
radiation emerging from the finite cylinder has no spatial dependence and that a vacuum surrounds the
cylinder.

**5. METHOD OF SOLUTION**

SPACETRAN-I uses the surface angular fluxes calculated by the discrete ordinates S_{n} code, CCC-82/ANISN, as input. SPACETRAN-II assumes that the surface angular flux for all energies can be
represented as a function cos^{N}phi, where phi is the angle between surface outward normal and
radiation direction, and N is an integer specified by the user. SPACETRAN III uses surface angular
fluxes from DOT III.

The energy group structure and the number and location of detectors is arbitrary. The flux (or response function) for a given energy group at some detection point are computed by summing the contributions from each surface area element over the entire surface. The surface area elements are defined by input data.

SPACETRAN-I handles contributions either from a cylinder "end" or "side," so the total contribution must be obtained by adding the results of separate end and side runs. ANISN angular fluxes are specified for discrete directions. In general, the direction between the detector and contributing area will not exactly coincide with one of these discrete directions. In this case, the ANISN angular flux for the "closest" discrete direction is used to approximate the contribution to the detector. SPACETRAN-II handles contributions from both the side and end of a cylinder in a single run. Since the assumed angular distribution is specified by a continuous function, it is not necessary to perform the angle selection described above. For each detector specified, both versions compute the flux and a response proportional to flux in each energy group and also compute the sum of these quantities over all energy groups.

SPACETRAN III calculates neutron or gamma-ray flux at arbitrary points in space exterior to a
2-D right circular cylindrical system which has been calculated by the discrete ordinates code system,
DOT.

**6. RESTRICTIONS OR LIMITATIONS**

There are limitations on the dimensions of certain arrays, but these dimensions can probably be
increased somewhat to meet the user's requirements.

**7. TYPICAL RUNNING TIME**

Estimated running time of each packaged sample problem: 1 minute.

**8. COMPUTER HARDWARE REQUIREMENTS**

SPACETRAN was designed for an IBM 360/75/91 computer and uses standard I-O units.

**9. COMPUTER SOFTWARE REQUIREMENTS**

The code is operable on the IBM 360/75/91 Operating System using OS-360 Fortran H compiler.

**10. REFERENCES**

S. N. Cramer and M. Solomito, "SPACETRAN: A Code to Calculate Dose at Detectors at Various Distances from the Surface of a Cylinder," ORNL-TM-2592 (June 1969).

Glenn Haynes, "SPACETRAN III," Informal Notes (September 1973).

F. R. Mynatt, et al., "Determination of the Flux in an External Void," UCND Report CTC-INF-952, Section III (August 1969).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source
code and sample problem input and output.

**12. DATE OF ABSTRACT**

August 1971; revised December 1984.

**KEYWORDS: ** KERNEL; NEUTRON; GAMMA-RAY; SPATIAL INTEGRATION; DISCRETE
ORDINATES