  Here we report the generation of MeV alpha-particles from H-11B fusion
initiated by laser-accelerated boron ions. Boron ions with maximum energy of
6MeV and fluence of 10^9/MeV/sr@5MeV were generated from 60-nm-thick
self-supporting boron nanofoils irradiated by 1J femtosecond pulses at an
intensity of 10^19W/cm^2. By bombarding secondary hydrogenous targets with the
boron ions, 3*10^5/sr alpha-particles from H-11B fusion were registered, which
is consistent with the theoretical yield calculated from the measured boron
energy spectra. Our results demonstrate an alternative way toward ultrashort
MeV alpha-particle sources employing compact femtosecond lasers. The ion
acceleration and product measurement scheme are referential for the studies on
the ion stopping power and cross-section of the H-11B reaction in solid or
plasma.
