**1. NAME AND TITLE**

EGAD: Calculation of Dose from External Gamma-Ray Emitters.

**2. CONTRIBUTOR**

Savannah River Laboratory, Aiken, South Carolina.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN IV; IBM 360/370.

**4. NATURE OF PROBLEM SOLVED**

EGAD calculates gamma-ray dose integrals to a ground level receptor (for incremental values
of the vertical dispersion parameter sigma_{z}), as a function of gamma-ray energy and spatial
distribution of the radioactive material. The dose integrals are representative of sector averages
since the distribution of material is assumed to be Gaussian in the vertical, homogeneous in the
horizontal, and bounded between ground level and an inversion lid. Calculated dose integrals are
independent of radioactive decay, transport velocity, down-wind distance, and sector width. Space
attenuation and buildup are accounted for.

**5. METHOD OF SOLUTION**

The plume of radioactive material is assumed to remain constant in shape and size during
passage over a receptor point. The space distribution of material is then represented as parallel line
sources. The line contributions are integrated analytically by transforming to Bessel and related
functions, reducing the spatial distribution to a vertical plane at the receptor point. Plane integrations are then performed by Gaussian quadratures.

**6. RESTRICTIONS OR LIMITATIONS**

EGAD requires 40 K bytes of storage.

**7. TYPICAL RUNNING TIME**

Running time to evaluate integrals is typically less than 30 msec for each energy and receptor
point.

**8. COMPUTER HARDWARE REQUIREMENTS**

EGAD is operable on the IBM 360/370 computers. It required 50 K bytes of storage for the
GO step on the IBM 360/91.

**9. COMPUTER SOFTWARE REQUIREMENTS**

A FORTRAN IV compiler is required.

**10. REFERENCE**

R. E. Cooper, "EGADA Computer Program to Compute Dose Integrals from External
Gamma Emitters," DP-1304 (September 1972).

**11. CONTENTS OF CODE PACKAGE**

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

**12. DATE OF ABSTRACT**

May 1975.

**KEYWORDS: ** GAMMA-RAY; KERNEL; AIRBORNE; ENVIRONMENTAL DOSE