A Multi-Component Measurement of the Cosmic Ray Composition Between 10^{17} eV and 10^{18} eV
/ Authors
T.Abu-Zayyad, K.Belov, D.J.Bird, J.Boyer, Z.Cao, M.Catanese, G.F.Chen, R.W.Clay, C.E.Covault, J.W.Cronin
and 38 more authors
H.Y.Dai, B.R.Dawson, J.W.Elbert, B.E.Fick, L.F.Fortson, J.W.Fowler, K.G.Gibbs, M.A.K.Glasmacher, K.D.Green, Y.Ho, A.Huang, C.C.Jui, M.J.Kidd, D.B.Kieda, B.C.Knapp, S.Ko, C.G.Larsen, W.Lee, E.C.Loh, E.J.Mannel, J.Matthews, J.N.Matthews, B.J.Newport, D.F.Nitz, R.A.Ong, K.M.Simpson, J.D.Smith, D.Sinclair, P.Sokolsky, P.Sommers, C.Song, J.K.K.Tang, S.B.Thomas, J. Velde, L.R.Wiencke, C.R.Wilkinson, S.Yoshida, X.Z.Zhang
/ Abstract
The average mass composition of cosmic rays with primary energies between 10 17 eV and 10 18 eV has been studied using a hybrid detector consisting of the High Resolution Fly’s Eye (HiRes) prototype and the MIA muon array. Measurements have been made of the change in the depth of shower maximum, X max , and in the change in the muon density at a fixed core location, ρ µ (600 m ), as a function of energy. The composition has also been evaluated in terms of the combination of X max and ρ µ (600 m ). The results show that the composition is changing from a heavy to lighter mix as the energy increases.