Measurement of the cosmic-ray energy spectrum and composition from 10(17) to 10(18.3) eV using a hybrid technique

Authors
Abu-Zayyad, T Belov, K Bird, DJ Boyer, J Cao, Z Catanese, M Chen, GF Clay, RW Covault, CE Dai, HY Dawson, BR Elbert, JW Fick, BE Fortson, LF Fowler, JW Gibbs, KG Glasmacher, MAK Green, KD Ho, Y Huang, A Jui, CC Kidd, MJ Kieda, DB Knapp, BC Ko, S Larsen, CG Lee, W Loh, EC Mannel, EJ Matthews, J Matthews, JN Newport, BJ Nitz, DF Ong, RA Simpson, KM Smith, JD Sinclair, D Sokolsky, P Sommers, P Song, C Tang, JKK Thomas, SB van der Velde, JC Wiencke, LR Wilkinson, CR Yoshida, S Zhang, XZ
Citation
T. Abu-zayyad et al., Measurement of the cosmic-ray energy spectrum and composition from 10(17) to 10(18.3) eV using a hybrid technique, ASTROPHYS J, 557(2), 2001, pp. 686-699
Citations number
42
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004637X → ACNP
Volume
557
Issue
2
Year of publication
2001
Part
1
Pages
686 - 699
Database
ISI
SICI code
0004-637X(200108)557:2<686:MOTCES>2.0.ZU;2-C
Abstract
We study the spectrum and average mass composition of cosmic rays with prim ary energies between 10(17) and 10(18) eV using a hybrid detector consistin g of the High Resolution Fly's Eye (HiRes) prototype and the Michigan Muon Array (MIA). Measurements have been made of the change in the depth of show er maximum as a function of energy. A complete Monte Carlo simulation of th e detector response and comparisons with shower simulations leads to the co nclusion that the cosmic-ray intensity is changing from a heavier to a ligh ter composition in this energy range. The spectrum is consistent with earli er Fly's Eye measurements and supports the previously found steepening near 4 x 10(17) eV.