title: Vacuum-free x-ray source based on ultrashort laser irradiation of solids.
abstract: A vacuum-free ultrafast laser-based x-ray source is demonstrated. Hard x-rays up to 80KeV are generated from Cu, Mo, Ag, Sn, and Ge targets in a laminar helium flow surrounded by atmosphere using tightly focused 33fs, 3mJ laser pulses. X-ray spectra, conversion efficiencies, and source sizes are presented. Six-fold efficiency improvement is observed, over similar sources found in the literature [1]. Source sizes determined for Cu and Mo show distinct dependences on laser pulse energy. It is also shown that the Cu source size has no dependence on the presence of the spectral band around the 8KeV K-shell lines.
authors.affiliation: Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, MI 48109-2099, USA. houbx@eecs.umich.edu
authors.forename: Bixue
authors.initials: B
authors.lastname: Hou
authors.forename: James
authors.initials: J
authors.lastname: Easter
authors.forename: Aghapi
authors.initials: A
authors.lastname: Mordovanakis
authors.forename: Karl
authors.initials: K
authors.lastname: Krushelnick
authors.forename: John A
authors.initials: JA
authors.lastname: Nees