RSIC COMPUTER CODE PSR-032

1. NAME AND TITLE

CUPED: Scintillation Spectrometer Polyenergetic Gamma Photon Experimental Distributions Unfolding Code.

CUPED is a much modified version of CUBED.

2. CONTRIBUTOR

NUS Corporation, Rockville, Maryland.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 360/75/91.

4. NATURE OF PROBLEM SOLVED

CUPED unfolds sodium-iodide (thallium-activated) scintillation spectrometer polyenergetic gamma photon experimental distributions. It is designed to analyze the combination bremsstrahlung and monoenergetic gamma radiation field of cylindrical radioisotope power generators.

5. METHOD OF SOLUTION

CUPED generates the detector system response matrix function and applies it to the monoenergetic spectral components discretely and to the bremsstrahlung iteratively. It corrects for iodine K X-ray escape, detector non-linearity, system drift, source decay, background, and detection efficiency. Results are presented in digital form for differential and integrated photon number and energy distributions and exposure dose.

The standard spectra are normalized with respect to photopeak pulse-height and area and their photopeaks subtracted to obtain normalized Compton continua. The response matrix vectors are determined at each energy by interpolating the normalized continua and computing the associated Gaussian photopeaks. The thus interpolated vectors are redistributed in pulse-height to correspond to the detector system energy response and to satisfy the requirements of the spectra to be unfolded. Quadratic interpolation of the normalized continua is carried out either directly for gamma photon energies < 0.6616 MeV or by a method of parts, described in this report, for energies > 0.6616 MeV.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

No study has been made by RSIC of typical running times for CUPED.

8. COMPUTER HARDWARE REQUIREMENTS

CUPED is operable on the IBM 360/75/91 computers.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

10. REFERENCES

J. J. Steyn, U. Born, J. T. Strahl, and R. Huang, "Code CUPED: A Code to Unfold Scintillation Spectrometer Polyenergetic Gamma Photon Experimental Distributions," NUS-557 (September 1969).

J. J. Steyn and D. G. Andrews, "A Comprehensive System for Computer Gain Changing of Scintillation Spectra," J. Nucl. Sci. Eng. Vol. 35, No. 3 (March 1968) 394-403.

11. CONTENTS OF CODE PACKAGE

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

12. DATE OF ABSTRACT

November 1983.