Comparison between methods for the determination of the primary cosmic   ray mass composition from the longitudinal profile of atmospheric cascades
  The determination of the primary cosmic ray mass composition from the longitudinal development of atmospheric cascades is still a debated issue. In this work we discuss several data analysis methods and show that if the entire information contained in the longitudinal profile is exploited, reliable results may be obtained. Among the proposed methods FCC ('Fit of the Cascade Curve'), MTA ('Multiparametric Topological Analysis') and NNA ('Neural Net Analysis') with conjugate gradient optimization algorithm give the best accuracy. 
M.Ambrosio, C.Aramo, C.Donalek, D.D'Urso, A.D.Erlykin, F.Guarino,   A.Insolia, G.Longo