title: Relativistic positron creation using ultraintense short pulse lasers.
abstract: We measure up to 2x10;{10} positrons per steradian ejected out the back of approximately mm thick gold targets when illuminated with short ( approximately 1 ps) ultraintense ( approximately 1x10;{20} W/cm;{2}) laser pulses. Positrons are produced predominately by the Bethe-Heitler process and have an effective temperature of 2-4 MeV, with the distribution peaking at 4-7 MeV. The angular distribution of the positrons is anisotropic. Modeling based on the measurements indicate the positron density to be approximately 10;{16} positrons/cm;{3}, the highest ever created in the laboratory.
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.forename: Scott C
authors.initials: SC
authors.lastname: Wilks
authors.forename: James D
authors.initials: JD
authors.lastname: Bonlie
authors.forename: Edison P
authors.initials: EP
authors.lastname: Liang
authors.forename: Jason
authors.initials: J
authors.lastname: Myatt
authors.forename: Dwight F
authors.initials: DF
authors.lastname: Price
authors.forename: David D
authors.initials: DD
authors.lastname: Meyerhofer
authors.forename: Peter
authors.initials: P
authors.lastname: Beiersdorfer