Gamma-neutron activation experiments using laser wakefield accelerators

Gamma-neutron activation experiments have been performed with relativistic electron beams produced by a laser wakefield accelerator. The electron beam s were produced by tightly focusing (spot diameter approximate to6 mum) a h igh power (up to 10 TW), ultra-short (greater than or equal to 50 fs) laser beam from a high repetition rate (10 Hz) Ti:sapphire (0.8 mum) laser syste m, onto a high density (> 10(19) cm(-3)) pulsed gasjet of length approximat e to1.5 mm. Nuclear activation measurements in lead and copper targets indi cate the production of electrons with energy in excess of 25 MeV. This resu lt was confirmed by electron distribution measurements using a bending magn et spectrometer. Measured gamma -ray and neutron yields are also found to b e in reasonable agreement with simulations using a Monte Carlo transport co de. (C) 2001 American Institute of Physics.