1. NAME AND TITLE

FERDO/FERD: Multichannel Neutron and Gamma-Ray Spectrum Matrix Unfolding Code Systems.

2. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 3033.

4. NATURE OF PROBLEM SOLVED

FERDO and FERD solve the integral equation which relates a measured pulse-height distribution and associated uncertainties to the true energy spectrum of the incident radiation.

5. METHOD OF SOLUTION

FERDO uses the method of constrained least-squares and biased estimation to solve a discretized representation of the integral unfolding problem and to compute a 2-sigma confidence interval for the true energy spectrum. FERD improves the FERDO solution by iteratively modifying the biased estimator.

6. RESTRICTIONS OR LIMITATIONS

FERDO/FERD require accurate estimations of the actual detector response and the idealized detector response (normally the detector energy resolution). In-core memory requirements are roughly three times the size of the response matrix (number of rows times the number of columns) for FERDO and four times the size of the response matrix for FERD. Additionally, a scratch storage device must be specified for both FERDO and FERD.

7. TYPICAL RUNNING TIME

Running time depends most strongly on the size of the response matrix. An 87 x 88 matrix problem required 4.5 s of IBM 3033 CPU time for FERDO and 15.2 s for FERD.

8. COMPUTER HARDWARE REQUIREMENTS

FERDO/FERD is operable on the IBM 3033 computer.

9. COMPUTER SOFTWARE REQUIREMENT

FERDO/FERD uses the proprietary DISSPLA graphics software package available from ISSCO, San Diego, California. It has been successfully run on the IBM 3033 computer under control of the MVS-JES2 Operating System. A Fortran IV compiler is required.

10. REFERENCE

B. W. Rust, D. T. Ingersoll, and W. R. Burrus, "A User's Manual for the FERDO and FERD Unfolding Codes," ORNL/TM-8720 (September 1983).

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

October 1983.