title: Evidence for changing of cosmic ray composition between 10(17) and 10(18) eV from multicomponent measurements
abstract: The average mass composition of cosmic rays with primary energies between 10(17) 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 and the muon density as a function of energy. The results show that the composition is changing from a heavy to lighter mix as the energy increases.
authors.affiliation: High Energy Astrophysics Institute, University of Utah, Salt Lake City, Utah 84112, USA.
authors.initials: T
authors.lastname: Abu-Zayyad
authors.initials: K
authors.lastname: Belov
authors.initials: DJ
authors.lastname: Bird
authors.initials: J
authors.lastname: Boyer
authors.initials: Z
authors.lastname: Cao
authors.initials: M
authors.lastname: Catanese
authors.initials: GF
authors.lastname: Chen
authors.initials: RW
authors.lastname: Clay
authors.initials: CE
authors.lastname: Covault
authors.initials: JW
authors.lastname: Cronin
authors.initials: HY
authors.lastname: Dai
authors.initials: BR
authors.lastname: Dawson
authors.initials: JW
authors.lastname: Elbert
authors.initials: BE
authors.lastname: Fick
authors.initials: LF
authors.lastname: Fortson
authors.initials: JW
authors.lastname: Fowler
authors.initials: KG
authors.lastname: Gibbs
authors.initials: MA
authors.lastname: Glasmacher
authors.initials: KD
authors.lastname: Green
authors.initials: Y
authors.lastname: Ho
authors.initials: A
authors.lastname: Huang
authors.initials: CC
authors.lastname: Jui
authors.initials: MJ
authors.lastname: Kidd
authors.initials: DB
authors.lastname: Kieda
authors.initials: BC
authors.lastname: Knapp
authors.initials: S
authors.lastname: Ko