1. NAME AND TITLE

EDISTR: Prepares a Nuclear Decay Data Base for Internal Radiation Dosimetry Calculations.

AUXILIARY ROUTINES

BLDCCT: Creates conversion coefficient data file for EDISTR program.

BUILDU: Creates data files for running EDISTR program.

LISDAT: Prints listing of data files prepared for running EDISTR program.

SCHEME: Prepares a DISSPLA compressed plot file containing device-independent instructions for plotting the decay schemes.

2. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

Fortran IV and Assembler Language; IBM 370/3033.

4. NATURE OF PROBLEM SOLVED

EDISTR uses as input basic radioactive decay data from the Evaluated Nuclear Structure Data File developed by the Nuclear Data Project at Oak Ridge National Laboratory and now maintained by Brookhaven National Laboratory. It calculates the mean energies and absolute intensities of all principal radiations associated with the radioactive decay of a nuclide. The program provides a physical data base for internal dosimetry calculations or other calculations requiring detailed decay data. The principal calculations performed by EDISTR are the determination of (1) the average energy of beta particles in a beta transition, (2) the beta spectra as a function of energy, (3) the energies and intensities of X rays and Auger electrons generated by radioactive decay processes, (4) the bremsstrahlung spectra accompanying beta decay and monoenergetic Auger and internal conversion electrons, and (5) the radiations accompanying spontaneous fission.

5. METHOD OF SOLUTION

1. Alpha decay. Kinetic energies of the alpha particles and the associated recoil nuclei are computed using conservation of energy and momentum principles. The input data consist of the ground-state Q value, the various excitation energies of the levels in the daughter nuclide at which the alpha transitions end, and the corresponding alpha intensities.

2. Beta decay. The average energies of the beta particles and the emitted continuous spectra are calculated using the Fermi theory of beta decay with the input of additional data to determine the forbiddenness of the beta spectra.

3. Electron-Capture decay. The distribution of primary vacancies created in the various atomic shells and subshells as a result of the electron-capture process are calculated using the K/L/M capture ratios.

4. Internal conversion of gamma rays. This is a process by which the energy of a transition between two states of a nucleus is transferred to an orbital electron. The distribution of the primary vacancies in the various atomic shells and the energies and intensities of conversion electrons are calculated.

5. X-ray and Auger-electron intensities and energies. Intensities of X rays and Auger electrons are obtained using the numbers of primary vacancies in the various subshells for electron capture or for internal conversion of electrons.

6. Spontaneous fission. The fission decay fraction, the number of neutrons emitted per fission, the mass number of the parent nuclide, and the atomic number of the parent nuclide are used to compute intensities and energies for spontaneous fission fragments, neutrons, beta particles, prompt gamma rays, and delayed gamma rays.

7. Bremsstrahlung radiation. Bremsstrahlung spectra associated with beta particles and monoenergetic conversion and Auger electrons are calculated.

6. RESTRICTIONS OR LIMITATIONS

Direct Access Datasets MASTER and SUBMAS may run out of space if more than 10-15 nuclides are done at the same time. Storage space must be increased in both the JCL and the DEFINE FILE statements in the source program to process more nuclides at one time.

SCHEME has been run with DISSPLA version 8.2. It has not been tested with version 9.

7. TYPICAL RUNNING TIME

The sample problem, when run on the IBM 3033 computer, required the following for each of the programs:

BLDCCT 9 seconds and 800 I/Os

BUILDU 4 seconds and 4,000 I/Os

LISDAT 10 seconds and 4,000 I/Os

EDISTR 21 seconds and 4,000 I/Os

SCHEME 5 seconds and 3,000 I/Os

8. COMPUTER HARDWARE REQUIREMENTS

EDISTR is operable on the IBM 370/3033 computers. Online storage space is required for direct access datasets.

9. COMPUTER SOFTWARE REQUIREMENTS

Fortran IV and Assembler Language compilers are required.

DISSPLA Version 8.2 (a proprietary software product of Integrated Software Systems Corporation, San Diego, California) is required for the SCHEME program, only.

10. REFERENCE

L. T. Dillman, "EDISTR--A Computer Program to Obtain a Nuclear Data Base for Radiation Dosimetry," ORNL/TM-6689 (January 1980).

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

January 1984.