title: High-quality electron beams from a helical inverse free-electron laser accelerator.
abstract: Compact, table-top sized accelerators are key to improving access to high-quality beams for use in industry, medicine and academic research. Among laser-based accelerating schemes, the inverse free-electron laser (IFEL) enjoys unique advantages. By using an undulator magnetic field in combination with a laser, GeV m(-1) gradients may be sustained over metre-scale distances using laser intensities several orders of magnitude less than those used in laser wake-field accelerators. Here we show for the first time the capture and high-gradient acceleration of monoenergetic electron beams from a helical IFEL. Using a modest intensity (~10(13) W cm(-2)) laser pulse and strongly tapered 0.5 m long undulator, we demonstrate >100 MV m(-1) accelerating gradient, >50 MeV energy gain and excellent output beam quality. Our results pave the way towards compact, tunable GeV IFEL accelerators for applications such as driving soft X-ray free-electron lasers and producing γ-rays by inverse Compton scattering.
authors.affiliation: Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA.
authors.forename: J
authors.initials: J
authors.lastname: Duris
authors.affiliation: Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA.
authors.forename: P
authors.initials: P
authors.lastname: Musumeci
authors.affiliation: Accelerator Test Facility, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: M
authors.initials: M
authors.lastname: Babzien
authors.affiliation: Accelerator Test Facility, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: M
authors.initials: M
authors.lastname: Fedurin
authors.affiliation: Accelerator Test Facility, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: K
authors.initials: K
authors.lastname: Kusche
authors.affiliation: Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA.
authors.forename: R K
authors.initials: RK
authors.lastname: Li
authors.affiliation: Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA.
authors.forename: J
authors.initials: J
authors.lastname: Moody
authors.affiliation: Accelerator Test Facility, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: I
authors.initials: I
authors.lastname: Pogorelsky
authors.affiliation: Accelerator Test Facility, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: M
authors.initials: M
authors.lastname: Polyanskiy
authors.affiliation: Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Rosenzweig
authors.affiliation: Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Sakai
authors.affiliation: Accelerator Test Facility, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: C
authors.initials: C
authors.lastname: Swinson
authors.affiliation: Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA.
authors.forename: E
authors.initials: E
authors.lastname: Threlkeld
authors.affiliation: Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA.
authors.forename: O
authors.initials: O
authors.lastname: Williams
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: V
authors.initials: V
authors.lastname: Yakimenko