1. NAME AND TITLE

ISOGEN II: Radioisotope Generator Code.

2. CONTRIBUTOR

Battelle Northwest Laboratories, Chemical Laboratory, Richland, Washington developed and contributed ISOGEN, an IBM 7090 version.

ISOGEN II (a modified ISOGEN) was contributed by The Dow Chemical Company, Rocky Flats Division, Golden, Colorado.

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV: IBM 360/50/75/91.

4. NATURE OF PROBLEM SOLVED

The purpose of isotope generation is to determine the change in isotopic concentration of an element; hence, to determine the specific activity over extended periods of time; to determine procedures necessary to analyze for any particular element; to determine if nuclides or elements are present in detectable quantities; and to predict the isotopic concentration and impurity content of the final product at any given time in the future.

ISOGEN was developed for extrapolating the quantities of nuclides that are or will be present in radioactive material previously analyzed for isotopic content by radiochemical methods. The original code was modified to remove procedures about reactor operations leaving procedures for calculating the concentrations of radioactive decay products. The list of nuclides was expanded to more than 300, ranging from atomic numbers 81 through 102. A time sequence element was added, making it possible to compute decay products for any selected time increment. Also, to aid laboratories performing radiochemical analyses, an additional step was included to permit computing the alpha and beta disintegrations for each nuclide present.

ISOGEN II calculates radioisotope generation and decay with branching by radioactive decay, neutron capture or fission by any chain member. Decay chains are generated from basic nuclear data and initial parent nuclides. For the fission process, the identity of primary fission products of interest must be specified. Output is expressed in units of atoms, grams, curies, beta watts, and gamma watts.

5. METHOD OF SOLUTION

The solution of the differential equations of radioactive growth and decay given an equation for calculating the amount of a single daughter produced by a single parent. This equation is applied repetitively until all combinations of parent and daughter are exhausted. The integrated equations were rearranged to forms which will yield accurate results and the form most easily applied to a particular set of data is used for calculation.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

No typical time noted.

8. COMPUTER HARDWARE REQUIREMENTS

Originally designed for the IBM 7090, it was rewritten for the CDC 3600 and the current package runs on the IBM 360/370 system.

9. COMPUTER SOFTWARE REQUIREMENTS

IBM FORTRAN IV systems.

10. REFERENCES

Informal Memo: ISOGEN Isotope Generator, Dow Chemical Company (March 1970).

C. R. Forrey, Jr., "A Computer Program for Determining the Growth of Nuclides from Radioactive Decay," Dow Chemical Company RFP-1098 (March 1969).

H. H. Van Tuyl, "Isogen - A Computer Code for Radioisotope Generation Calculations," HW-83785 (September 1964).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source code, a nuclide data library, and input data for a sample problem, and an output listing from running the problem.

12. DATE OF ABSTRACT

July 1967; updated July 1981, December 1984, October 1991.