title: Low-emittance electron bunches from a laser-plasma accelerator measured using single-shot x-ray spectroscopy.
abstract: X-ray spectroscopy is used to obtain single-shot information on electron beam emittance in a low-energy-spread 0.5 GeV-class laser-plasma accelerator. Measurements of betatron radiation from 2 to 20 keV used a CCD and single-photon counting techniques. By matching x-ray spectra to betatron radiation models, the electron bunch radius inside the plasma is estimated to be ~0.1 μm. Combining this with simultaneous electron spectra, normalized transverse emittance is estimated to be as low as 0.1 mm mrad, consistent with three-dimensional particle-in-cell simulations. Correlations of the bunch radius with electron beam parameters are presented.
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: G R
authors.initials: GR
authors.lastname: Plateau
authors.forename: C G R
authors.initials: CG
authors.lastname: Geddes
authors.forename: D B
authors.initials: DB
authors.lastname: Thorn
authors.forename: M
authors.initials: M
authors.lastname: Chen
authors.forename: C
authors.initials: C
authors.lastname: Benedetti
authors.forename: E
authors.initials: E
authors.lastname: Esarey
authors.forename: A J
authors.initials: AJ
authors.lastname: Gonsalves
authors.forename: N H
authors.initials: NH
authors.lastname: Matlis
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: C B
authors.initials: CB
authors.lastname: Schroeder
authors.forename: S
authors.initials: S
authors.lastname: Shiraishi
authors.forename: T
authors.initials: T
authors.lastname: Sokollik
authors.forename: J
authors.initials: J
authors.lastname: van Tilborg
authors.forename: Cs
authors.initials: C
authors.lastname: Toth
authors.forename: S
authors.initials: S
authors.lastname: Trotsenko
authors.forename: T S
authors.initials: TS
authors.lastname: Kim
authors.forename: M
authors.initials: M
authors.lastname: Battaglia
authors.forename: Th
authors.initials: T
authors.lastname: Stöhlker
authors.forename: W P
authors.initials: WP
authors.lastname: Leemans