title: McGehee et al. reply.
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: W R
authors.initials: WR
authors.lastname: McGehee
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Kondov
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: W
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Zirbel
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: B
authors.initials: B
authors.lastname: DeMarco