FITBOR: a new program for the analysis of complex alpha spectra

The fitting of complex alpha spectra requires the application of efficient algorithms. The Levenberg—Marquardt method has revealed itself as a very efficient procedure giving as a result a complete set of optimal fitting parameters, as well as their uncertainties and covariances. Alpha spectra have been fitted to the line shape formed by the convolution of a Gaussian curve with one, two, or three left-handed exponentials in the low-energy-tail region. The influence of a step function on the tail was also considered. Conclusions about the optimal model to be employed for each type of spectrum are drawn in this work. A FORTRAN code, FITBOR, based on this approach has been written and applied to the analysis of reference alpha-particle spectra. The resulting emission probabilities are reviewed as a check.