**RSIC COMPUTER CODE PSR-017**

**1. NAME AND TITLE**

FERDOR-COOLC: Spectra Unfolding Codes.

**2. CONTRIBUTORS**

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

Gulf Radiation Technology, San Diego, California.

**3. CODING LANGUAGE AND COMPUTER**

Fortran II; IBM 7090 (A). Fortran IV; UNIVAC 1108 (B). Fortran IV; IBM 360 (C).

**4. NATURE OF PROBLEM SOLVED**

FERDOR-COOLC is designed to calculate a neutron energy spectrum from a pulse-height
spectrum produced by a detector system using the liquid scintillator NE-213.

**5. METHOD OF SOLUTION**

The program estimates the counts which would be observed in an ideal detector system having a response which is specified by the user. The solution implicitly takes into account the non-negativity of the desired neutron spectrum. The solution is obtained by finding a nearly optimal combination of slices through the spectrometer response functions such that their sum approximates the response of a channel of the ideal analyzer and then uses the coefficients so determined to obtain an estimate of the desired neutron spectrum.

The principal difference between FERDOR and COOLC is that the latter includes provision for
arranging the observed pulse-height spectrum in appropriate bins; this operation must be carried out
separately in the former. Both programs require the user to furnish a matrix of actual response
functions and one of idealized response functions.

**6. RESTRICTIONS OR LIMITATIONS**

None noted.

**7. TYPICAL RUNNING TIME**

No study has been made by RSIC of typical running times for FERDOR-COOLC.

**8. COMPUTER HARDWARE REQUIREMENTS**

FERDOR is operable on the IBM 7090 computer (A) or the UNIVAC 1108 computer (B). COOLC is operable on the IBM 360 computer (C).

Approximately 300 K bytes are required for the sample problem.

**9. COMPUTER SOFTWARE REQUIREMENTS**

THE IBM 7090 version of FERDOR (A) is written in Fortran II. The UNIVAC 1108 version of
FERDOR is written in Fortran IV. A standard ASA Fortran IV compiler may be used for COOLC.

**10. REFERENCES**

B. W. Rust and W. R. Burrus, "Suboptimal Methods for Solving Estimation Problems," TPR-0145 (DASA 2604) (January 1971).

W. R. Burrus and V. V. Verbinski, "Fast-Neutron Spectroscopy with Thick Organic Scintillators," ORNL-TM-2225 (June 1968).

C. E. Clifford, E. A. Straker, F. J. Muckenthaler, V. V. Verbinski, R. M. Freestone, Jr., K. M.
Henry, and W. R. Burrus, "Measurements of the Spectra of Uncollided Fission Neutrons Transmitted
Through Thick Samples of Nitrogen, Oxygen, Carbon, and Lead: Investigation of the Minima in Total
Cross Sections," *Nucl. Sci. Eng.* 27 (1967) 299-307.

W. R. Burrus and C. Schneeberger, "A Simple Algorithm for Computing the Generalized Inverse
of a Matrix," *Communications of the ACM*, Vol 9, No. 5 (May 1966) 381-385.

V. V. Verbinski, J. C. Courtney, and N. Betz, "A Method of Evaluating Fast-Neutron Differential
Scattering Cross Sections with Short Experimental Runs," *Nucl. Inst. Meth.* 52 (1967) 181-192.

R. L. Heath, "Data Processing Techniques for Routine Application of Gamma-Ray Scintillation Spectrometry," TID-7594, Symposium (1960) 147-158.

W. Zobel, "Spectrometry for Gamma Rays from Proton-Bombarded Nuclei," ORNL-3360 (1969) 306-309.

L. Harris, Jr., H. Kendrick, Y. D. Naliboff, and S. M. Sperling, "Time-Dependent Fast Neutron and Secondary Gamma Ray Spectrum Measurements in Concrete", GA-9751, Vol. II (DASA 2401-2) Appendix B (November 1969).

H. Kendrick and S. M. Sperling, "An Introduction to the Principles and Use of the FERDOR Unfolding Code," GA-9882 (January 1970).

W. R. Burrus, "Utilization of A Priori Information by Means of Mathematical Programming in the Statistical Interpretation of Measured Distributions," ORNL-3743 (June 1965).

R. S. Booth, "A Comparison of Folding and Unfolding Techniques for Determining the Gamma
Spectrum from Thermal Neutron Capture in Aluminum," *Nucl. Inst. Meth.* 85 (1970) 69-76. Informal
Notes.

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source
code and data (A), the source code only (B), or the source code and data, plus output from the sample
problem (C).

**12. DATE OF ABSTRACT**

September 1972; updated November 1983.

**KEYWORD: ** UNFOLDING