**1. NAME AND TITLE**

QADMOD-GP: Point Kernel Gamma-Ray Shielding Code With Geometric Progression
Buildup Factors.

**2. CONTRIBUTOR**

TU Electric, Glen Rose, Texas.

**3. CODING LANGUAGE AND COMPUTER**

Fortran 77; IBM PC.

**4. NATURE OF PROBLEM SOLVED**

QADMOD-GP is a PC version of the mainframe code CCC-396/QADMOD-G, a point-kernel
integration code for calculating gamma ray fluxes and dose rates or heating rates at specific detector
locations within a three-dimensional shielding geometry configuration due to radiation from a volume-distributed source.

**5. METHOD OF SOLUTION**

QADMOD-GP calculates gamma-ray fluxes, dose rates, or heating rates at discrete locations within
a complex source-geometry configuration by representing a volume-distributed source by a number
of point isotropic sources and computing the distances through all regions traversed by the line-of-sight
from the source points to a desired receiver point. From these distances and the characteristics of the
materials within them, energy-dependent exponential attenuation factors and energy-dependent buildup
factors for gamma-rays are applied to calculate the direct gamma-ray dose and the gamma-ray dose
with buildup. Like QADMOD-G, QADMOD-GP employs the FASTER geometry routines to define
region boundaries with the general quadric surface equation. Additional features of the PC version are
the following: 1) use of the geometric progression buildup factors; 2) addition of subroutine to allow
use of updated mass attenuation coefficients (without coherent scattering); 3) addition of subroutine
to compute flux-to-dose rate conversion factors for arbitrary photon energies; 4) increase of the
number of allowable computed source point locations (from 500 to 3,000); 5) increase the exponential
function minimum (from -180.218 to -87.0) in KERNEL to avoid underflows; 6) installation of a "card
image" routine to print formatted input data at the beginning.

**6. RESTRICTIONS OR LIMITATIONS**

The code can treat up to 300 shielding regions, 100 material compositions, and as many detectors
as desired.

**7. TYPICAL RUNNING TIME**

On the IBM PC/XT with a math co-processor, the sample problem took about 1 minute.

**8. COMPUTER HARDWARE REQUIREMENTS**

QADMOD-GP runs on the IBM PC and compatibles with a math co-processor.

**9. COMPUTER SOFTWARE REQUIREMENTS**

A Fortran 77 compiler is required. The IBM Professional Fortran Version 1.0 compiler was used
by TU Electric to create the executable program. Alternatively, The RM/Fortran compiler version
2.42 can be used.

**10. REFERENCES**

J. K. Warkentin, "QADMOD-GP Notes," Informal notes (November 2, 1990).

J. K. Warkentin, "Utilization Instructions For QADMOD-GP -- A PC Version Of QADMOD-G With Geometric Progression Buildup Factors," (November 1, 1990).

J. H. Price and W. G. M. Blattner, "Utilization Instructions for QADMOD-G," RRA-N7914
(December 1979).

**b. Background information:**

Y. Harima, Y. Sakamoto, S. Tanaka, and M. Kawai, "Validity of the Geometrical Progression
Formula in Approximating Gamma-Ray Buildup Factors," *Nucl. Sci. Eng.* 94, 24-35 (September
1986).

D. K. Trubey, "New Gamma-Ray Buildup Factor Data for Point Kernel Calculations: ANS-6.4.3
Standard Reference Data," ORNL/RSIC-49 (September 1988).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced document and one (1.2 MB) DOS diskette.

**12. DATE OF ABSTRACT**

November 1990.

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