**1. NAME AND TITLE**

UPEAK: A Program for Decomposing A One-Dimensional Spectrum

**2. CONTRIBUTOR**

Joint Institute of Nuclear Research, Dubna, USSR, through NEA Data Bank, France.

**3. CODING LANGUAGE AND COMPUTER**

Fortran 77; IBM PC/XT; IBM PC/AT.

**4. NATURE OF PROBLEM SOLVED**

UPEAK was written for the purpose of decomposing a one-dimensional spectrum into its components.

**5. METHOD OF SOLUTION**

The spectrum of nuclear reactions may be formally considered as a linear combination: s(x) = SUM((fi(x),i=1,n) + b(x) + e(x); where fi(x) is the i-th component of interest, b(x) is the background and e(x) is the statistical error with zero-valued mean and variance d(x); s(x) is the spectrum. Each measured component is regarded as a result of a transformation of its model m(x). Regression analysis is used to determine the least squares estimates of some of the parameters.

**6. RESTRICTIONS OR LIMITATIONS**

A maximum of 20 components in the spectrum interval can be used.

**7. TYPICAL RUNNING TIME**

At the NEA Data Bank, the sample problem took about 4 minutes on an IBM PC/AT with a math co-processor.

**8. COMPUTER HARDWARE REQUIREMENTS**

IBM PC and compatibles with math co-processor.

**9. COMPUTER SOFTWARE REQUIREMENTS**

The code was written in Fortran 77 and uses RM Fortran Version 2.42 or higher compiler. The PLINK86 overlay linker is also necessary.

**10. REFERENCES**

``The Long Write Up of the Program UPEAK,'' informal notes by V. B. Zlokazov, JINR, Dubna, USSR.

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced document and one DS/HD (1.2 MG) 5.25 inch diskette.

**12. DATE OF ABSTRACT**

February 1991.

**KEYWORDS: ** GAMMA-RAY SPECTRUM ANALYSIS; INTERACTIVE, ON-LINE;
MICROCOMPUTER