title: Long duration backlighter experiments at Omega.
abstract: We have successfully demonstrated a 7.5 ns duration pinhole-apertured backlighter at the Omega laser facility. Pinhole-apertured point-projection backlighting for 8 ns will be useful for imaging evolving features in experiments at the National Ignition Facility. The backlighter consisted of a 20 microm diameter pinhole in a 75 microm thick Ta substrate separated from a Zn emitter (9 keV) by a 400 microm thick high-density carbon piece. The carbon prevented the shock from the laser-driven surface from reaching the substrate before 8 ns and helped minimize x-ray ablation of the pinhole substrate. Grid wires in x-ray framing camera images of a gold grid have a source-limited resolution significantly smaller than the pinhole diameter due to the high aspect ratio of the pinhole, but do not become much smaller at late times.
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA. reighard2@llnl.gov
authors.forename: A B
authors.initials: AB
authors.lastname: Reighard
authors.forename: S G
authors.initials: SG
authors.lastname: Glendinning
authors.forename: P E
authors.initials: PE
authors.lastname: Young
authors.forename: W W
authors.initials: WW
authors.lastname: Hsing
authors.forename: M
authors.initials: M
authors.lastname: Foord
authors.forename: M
authors.initials: M
authors.lastname: Schneider
authors.forename: K
authors.initials: K
authors.lastname: Lu
authors.forename: T
authors.initials: T
authors.lastname: Dittrich
authors.forename: R
authors.initials: R
authors.lastname: Wallace
authors.forename: C
authors.initials: C
authors.lastname: Sorce