1. NAME AND TITLE

WINDOWS: A Program for the Analysis of Spectral Data Foil Activation Measurements.

AUXILIARY ROUTINES

INTRIGUE-IIC: Logarithmic and Semilogarithmic Calcomp Plot Routines.

GREEK: /

DATA LIBRARY

CONVERT: An IBM-to-CDC Program Conversion Code.

WINDOWS is a simplified and slightly faster version of CCC-233/CRYSTAL BALL. Its name refers to its ability to model integral responses to a neutron flux. These responses may be thought of as views of the neutron spectrum through a "window" open between the bounds of integration and colored by the underlying response function.

2. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

Fortran IV, Assembler Language; IBM 360/370.

4. NATURE OF PROBLEM SOLVED

WINDOWS is capable of unfolding neutron differential spectra, estimating windows and detector contributions, laying upper and lower bounds for integral response, and obtaining group fluxes from neutron transport calculations.

5. METHOD OF SOLUTION

Unfolding the neutron spectrum amounts to inverting the set of integral equations (*). Since this problem in general has no unique solution, WINDOWS seeks the spectrum phi whose shape is closest to that of a trial spectrum psi, subject to the condition that (*) be satisfied within some preassigned tolerance. This minimization is achieved by manipulating the normal equations so that Gaussian elimination can be performed without the need for back-substitution.

6. RESTRICTIONS OR LIMITATIONS

WINDOWS can handle up to 40 foil measurements including group fluxes construed as ideal detectors.

7. TYPICAL RUNNING TIME

Running time is dependent upon the difficulty of the tasks posed to WINDOWS as well as the number of processing cycles included in the input. When the trial spectrum is in good agreement with the foil activation measurements, unfolding is quick--in the neighborhood of 1-2 sec CPU time per processing cycle on the IBM 360/91 computer. If the agreement is poor, several iterations will be required. The linear programming routines are quite time-consuming and can cause the time per cycle to increase to 10-15 sec.

8. COMPUTER HARDWARE REQUIREMENTS

WINDOWS is operable on the IBM 360/370 computers. It requires 374 K of core storage on the IBM 360/91 computer. Two tapes or discs are required. Output is sent to a line printer and to a disc plotter. The clock is not sampled.

9. COMPUTER SOFTWARE REQUIREMENTS

Fortran IV and Assembler Language compilers are required.

10. REFERENCES

Addendum to WINDOWS Documentation.

F. W. Stallmann, J. F. Eastham, and F. B. K. Kam, "Windows--A Program for the Analysis of Spectral Data Foil Activation Measurements," ORNL/TM-6656 (December 1978).

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, the cross-section library data, the trial spectrum library data.

12. DATE OF ABSTRACT

March 1984.