Experimental evaluation of various rigidity models

Abstract

Atmospheric cosmic-ray fluxes have recently been measured over large portions of the globe on a series of flights of a United States Air Force jet aircraft. The measured fluxes have been plotted as a function of the vertical cutoff rigidity for several different models. The rigorous trajectory calculations of Shea et al. give good agreement with the counting rates. The Makino model also orders these data equally well and therefore must be within a few percent of the value determined by rigorous orbit calculations taken over the portions of the globe covered in this survey. The other models are demonstrably worse, and a discussion of where these models are inadequate is given. Particular attention is paid to the use of the L parameter as a substitute for rigorous integration procedures. It is shown both experimentally and theoretically that the L parameter is not a good demographic parameter for galactic cosmic radiation at the lower latitudes, but it should be sufficiently accurate at higher latitudes for most purposes.