ALFITeX: a new code for the deconvolution of complex alpha-particle spectra

Improved peak shape fitting in alpha spectra

“…Whereas ALPHA generally performs very well, there are still noticeable residuals when fitting spectra that have millions of counts in each energy bin, since the extremely low random variations in the spectra reveal the slightest mismatch between fit and experiment. Similar imperfections show up with other analysis software, such as ALPACA (García-Toraño,1997) and ALFITEX (Caro Marroyo et al, 2013). Whereas ALFITEX applies the same peak model with the optional use of two or three exponentials (Eqs.…”

“…The statistical uncertainties on the fitted parameters, including the peak areas, can in principle be calculated from the covariance matrix. The corresponding equations have been published by Sibbens (1998), Ihantola et al (2011) and Caro Marroyo et al (2013). However, a minimum requirement is that the residuals are purely stochastic.…”

Alpha-particle spectrometry for the determination of alpha emitting isotopes in nuclear, environmental and biological samples: past, present and future

“…[62][63][64][65][66] The a-spectrum evaluation can be divided into three different topics i.e., (i) calculation of peak areas to determine the a-activity ratios of different a-emitting nuclides e.g., 238 Pu/ ( 239 Pu + 240 Pu), 243 Am/ 241 Am, 234 U/ 238 U, etc., referred to as simple alpha spectrometry (S-AS) in this manuscript, (ii) traditional high resolution alpha spectrometry (T-HRAS) to resolve close lying a-energy peaks e.g., 239 Pu and 240 Pu, 233 U and 234 U, 238 Pu and 241 Am, etc., and (iii) ultra-high resolution alpha spectrometry (U-HRAS) to determine the emission probabilities of various a-particle energies of a single radioactive nuclide e.g., 240 Pu, 241 Am, 238 U, etc. A number of computer algorithms have been developed in the past, [67][68][69][70][71][72][73][74][75][76][77][78][79] and the choice of a particular algorithm is governed by the application of the data and the This journal is © The Royal Society of Chemistry 2016 counting statistics of the alpha spectra. For example, in the case of environmental and biological samples, with a-spectra of low (poor) statistics, deconvolution of peaks is not needed because accurate determination of peak areas is of paramount importance.…”

“…A number of researchers have developed and used various computer programs to full this objective. [67][68][69][70][71][72][73][74][75][76][77][78][79] Many of these involve peak shape parameters and a Gaussian tting for the apeak in addition to 2 or 3 exponential functions for the low energy tail.…”

Study on deconvolution of alpha-particle spectra using metaheuristic optimization and multivariate analysis

“…In terms of the numerical method, two kinds of traditional gradient-based optimization methods, Levenberg-Marquardt (LM) [8,[10][11][12] and Generalized Reduced Gradient (GRG) [7] (An option of the built-in optimization routine, SOLVER in the commercial software EXCEL) are frequently employed in the previous work. LM is recognized as one of the most efficient algorithms for the non-linear least-squares fitting.…”