**1. NAME AND TITLE**

QAD-QC: Three-Dimensional Point Kernel Gamma-Ray Shielding Code.

**2. CONTRIBUTORS**

Power Authority of the State of New York, New York, New York.

Los Alamos National Laboratory, Los Alamos, New Mexico.

**3. CODING LANGUAGE AND COMPUTER**

Fortran IV; CDC, IBM 360/370.

**4. NATURE OF PROBLEM SOLVED**

QAD-QC is similar in all respects to QAD-P5 (CCC-48/QAD) except that all neutron moments data and heating calculations have been eliminated, the number of regions and boundaries has been reduced, and various changes to the output formats have been changed. This code version was developed for quick and fairly inexpensive direct-beam gamma-ray dose calculations.

QAD-QC calculates the direct-beam gamma-ray dose rates at points in three-dimensional space
from point, volumetric, and cosine intensity function sources. The source and dose points can be
described in either cartesian, cylindrical, or spherical coordinates, while the geometry description is
limited to Cartesian only.

**5. METHOD OF SOLUTION**

The original QAD-P5 utilized the point kernel method for gamma-ray penetrations and interpolated moments data for neutron penetrations in multi-dimensional shield configurations. QAD-QC is similar, except that all neutron and heating calculations have been eliminated and the number of regions and boundaries has been reduced.

QAD-QC solves the numerical integration of point sources in three-dimensional geometry.
Volumetric sources are divided up into a point source distribution, then integrated numerically. The
cosine intensity function sources are numerically integrated directly. The line-of-sight distance from
each point source to the dose point is then calculated. The uncollided gamma-ray flux at the dose point
is calculated, based on the distance traveled through each material region specified and the shielding
characteristics of each material. A buildup factor is then applied to this dose to take into account the
scattering component of the dose rate.

**6. RESTRICTIONS OR LIMITATIONS**

Since QAD-QC uses point kernel methods, the radiation sources, which are always volumetric,
are approximated by a distribution of point sources each of which contributes to the total dose rate or
flux at any given detection point. The program calculates the mean free path and the corresponding
buildup factor between each source point and the detector point by means of ray tracing. There are
limits to the number of source points which can be employed to facilitate this approximation. The
source points should be distributed in such a fashion as to concentrate a higher density of source points
within regions in the source volume which are within 4 mean free paths of the source boundary closest
to the detection point. One mean free path corresponds to a physical distance of approximately 5 to
10 cm for typical shielding materials.

**7. TYPICAL RUNNING TIME**

No study has been made by RSIC of typical running times for QAD-QC.

**8. COMPUTER HARDWARE REQUIREMENTS**

The code is operable on the CDC (A) or IBM 360/370 (B) computers.

**9. COMPUTER SOFTWARE REQUIREMENTS**

A Fortran IV compiler is required.

**10. REFERENCE**

R. Deem, "QAD-QC 3 Dimensional Point Kernel Gamma Shielding Code," RP-100 (July 1977).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced document and one (1.2MB) DOS diskette which contains the source
codes.

**12. DATE OF ABSTRACT**

February 1982; revised February 1983.

**KEYWORDS: ** KERNEL; GAMMA-RAY; COMPLEX GEOMETRY