Motivation and development of ultrafast laser-based accelerator techniques for chemical physics research

The products of radiation induced chemical reactions are determined by rapid primary processes such as energy transfer, thermalization and solvation. Ultrafast photoionization experiments on liquid water demonstrate that these initial events occur on time scales <5 ps and involve a complicated interplay between electronic relaxation and vibrational energy redistribution. These experiments also show that the chemical processes originating from ionizing radiation are unique and cannot be reproduced by laser photons alone. Due to the lack of a suitable femtosecond source of ionizing radiation, knowledge of the primary processes in radiation chemistry remains poor. To address this issue a 20 TW laser system has been constructed to obtain subpicosecond electron pulses with energies in the 1-10 MeV range. In addition to the production of femtosecond electron pulses, future efforts will be directed towards using this laser for accelerating heavier particles such as protons and generating hard X-rays.