Generating positrons with femtosecond-laser pulses

Utilizing a femtosecond table-top laser system, we have succeeded in converting via electron acceleration in a plasma channel, low-energy photons into antiparticles, namely positrons. The average intensity of this source of positrons is estimated to be equivalent to 2x10(8) Bq and it exhibits a very favorable scaling for higher laser intensities. The advent of positron production utilizing femtosecond laser pulses may be the forerunner to a table-top positron source appropriate for applications in material science, and fundamental physics research like positronium spectroscopy. (C) 2000 American Institute of Physics. [S0003-6951(00)00143-1].