**1. NAME AND TITLE**

BASACF: Bayesian Approach to Spectrum Adjustment with Covariance Filter.

**2. CONTRIBUTOR**

Institute of Radiation Dosimetry, Prague, Czechoslovakia.

**3. CODING LANGUAGE AND COMPUTER**

Fortran 77; IBM PC.

**4. NATURE OF PROBLEM SOLVED**

BASACF adjusts the neutron spectrum based on integral detector measurements and calculation
of an integral dosimetric quantity and its variance. BASACF consists of two independent programs:
BASADAT and BASAUNF. BASADAT calculates the L-D factors of all needed covariance matrices.
BASAUNF adjusts the spectrum by means of the covariance filter.

**5. METHOD OF SOLUTION**

BASACF uses Bayesian probability applied to a linearized relation between activities, dosimetry
cross sections and flux. All probability distributions are supposed to be normal.

**6. RESTRICTIONS OR LIMITATIONS**

This version can be used for 45 energy groups and 5 detectors.

**7. TYPICAL RUNNING TIME**

Using the sample problem TEST1D.DAT, the program BASADAT took about 30 minutes on an
IBM PC/XT with a math co-processor. Using the output corresponding to the same problem,
BASAUNF took about 4 minutes.

**8. COMPUTER HARDWARE REQUIREMENTS**

IBM PC and compatibles with or without a math co-processor.

**9. COMPUTER SOFTWARE REQUIREMENTS**

The code was written in Fortran 77 and was tested under PC-DOS (IBM PC). Executable files,
produced by the MICROSOFT's Fortran 77 compiler (version 4.01) and linker (version 3.64) are
included.

**10. REFERENCE**

M. Tichy, "The Program BASACF: PC Version, Description and User Guide," Report UDZ
254/88 (March 1990).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced document and a (1.2MB) DOS diskette.

**12. DATE OF ABSTRACT**

October 1990.

**KEYWORDS: ** MICROCOMPUTER; NEUTRON; UNFOLDING