title: Beam-halo measurements in high-current proton beams.
abstract: We present results from an experimental study of the beam halo in a high-current 6.7-MeV proton beam propagating through a 52-quadrupole periodic-focusing channel. The gradients of the first four quadrupoles were independently adjusted to match or mismatch the injected beam. Emittances and beamwidths were obtained from measured profiles for comparisons with maximum emittance-growth predictions of a free-energy model and maximum halo-amplitude predictions of a particle-core model. The experimental results support both models and the present theoretical picture of halo formation.
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA.
authors.forename: C K
authors.initials: CK
authors.lastname: Allen
authors.forename: K C D
authors.initials: KC
authors.lastname: Chan
authors.forename: P L
authors.initials: PL
authors.lastname: Colestock
authors.forename: K R
authors.initials: KR
authors.lastname: Crandall
authors.forename: R W
authors.initials: RW
authors.lastname: Garnett
authors.forename: J D
authors.initials: JD
authors.lastname: Gilpatrick
authors.forename: W
authors.initials: W
authors.lastname: Lysenko
authors.forename: J
authors.initials: J
authors.lastname: Qiang
authors.forename: J D
authors.initials: JD
authors.lastname: Schneider
authors.forename: M E
authors.initials: ME
authors.lastname: Schulze
authors.forename: R L
authors.initials: RL
authors.lastname: Sheffield
authors.forename: H V
authors.initials: HV
authors.lastname: Smith
authors.forename: T P
authors.initials: TP
authors.lastname: Wangler