Abstract
A critical analysis is made of recent calculations of the sea level cosmic ray proton and pion spectra expected at ground level and comparison is made with two sets of experimental data measured at Durham. Particular attention is directed towards the theoretical approach advanced by the present author in a previous paper (1971) and some misconceptions by Hook and Turver (1974) are pointed out. The work of Jabs (1968, 1972) is also considered. It is concluded that all three sets of calculations represent the data equally well.