All particle primary nucleon spectrum derived from the latest jacee data

The all particle primary nucleon spectrum has been estimated on the basis of the latest Japanese American Emulsion Experiments on the balloon borne emulsion chamber measurements of the fluxes of p, He, C, N, O, Ne, Mg, Si, Fe and low energy fit extrapolated results have been found to follow the power law fit of the formN(E) dE=2·03E^–2·7 dE (cm² s sr GeV/nucleon)^–1. The concept of nuclear fragmentation has been used to estimate the nucleon flux from nuclei spectra. The derived result agrees with the predicted primary spectrum after Yodh, Ellsworth, Stanev and Gaisser.Equipe de Recherche associée au C.N.R.S.Av. H. Fellow, on leave fromIndian Association for the Cultivation of Science, Jadavpur, Calcutta 700032, India.