Analysis of 239Pu, 244Cm and 243Am alpha spectra using the unfolding code Colégram without prior use of a nuclear data library

This paper shows the unfolding capabilities of a code developed in our laboratory when applied to alpha spectrometry. The code, called ‘Colégram’, uses the Levenberg–Marquardt algorithm. Colégram has some particularly interesting features when compared to other codes using χ2 as the convergence criterion. Low statistics peaks are treated more successfully. No nuclear data library is needed. The emission probabilities obtained with Colégram from 239Pu, 244Cm and 243Am alpha spectra characterized by high statistics and good energy resolution are presented. These emission probabilities and the alpha-particle energies deduced from them are compared to those obtained in the most recent works. We show that Colégram also offers the possibility of identifying and quantifying contaminants present in the spectra. Finally, with Colégram, it is necessary to identify electron conversion lines and include them in the unfolding process to increase the quality of the fits.