title: Proton radiography of a laser-driven implosion.
abstract: Protons accelerated by a picosecond laser pulse have been used to radiograph a 500 microm diameter capsule, imploded with 300 J of laser light in 6 symmetrically incident beams of wavelength 1.054 microm and pulse length 1 ns. Point projection proton backlighting was used to characterize the density gradients at discrete times through the implosion. Asymmetries were diagnosed both during the early and stagnation stages of the implosion. Comparison with analytic scattering theory and simple Monte Carlo simulations were consistent with a 3+/-1 g/cm3 core with diameter 85+/-10 microm. Scaling simulations show that protons>50 MeV are required to diagnose asymmetry in ignition scale conditions.
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Mackinnon
authors.forename: P K
authors.initials: PK
authors.lastname: Patel
authors.forename: M
authors.initials: M
authors.lastname: Borghesi
authors.forename: R C
authors.initials: RC
authors.lastname: Clarke
authors.forename: R R
authors.initials: RR
authors.lastname: Freeman
authors.forename: H
authors.initials: H
authors.lastname: Habara
authors.forename: S P
authors.initials: SP
authors.lastname: Hatchett
authors.forename: D
authors.initials: D
authors.lastname: Hey
authors.forename: D G
authors.initials: DG
authors.lastname: Hicks
authors.forename: S
authors.initials: S
authors.lastname: Kar
authors.forename: M H
authors.initials: MH
authors.lastname: Key
authors.forename: J A
authors.initials: JA
authors.lastname: King
authors.forename: K
authors.initials: K
authors.lastname: Lancaster
authors.forename: D
authors.initials: D
authors.lastname: Neely
authors.forename: A
authors.initials: A
authors.lastname: Nikkro
authors.forename: P A
authors.initials: PA
authors.lastname: Norreys
authors.forename: M M
authors.initials: MM
authors.lastname: Notley
authors.forename: T W
authors.initials: TW
authors.lastname: Phillips
authors.forename: L
authors.initials: L
authors.lastname: Romagnani
authors.forename: R A
authors.initials: RA
authors.lastname: Snavely
authors.forename: R B
authors.initials: RB
authors.lastname: Stephens
authors.forename: R P J
authors.initials: RP
authors.lastname: Town