Time-resolved spectroscopy at the picosecond laser-triggered electron accelerator ELYSE

ELYSE is a fast kinetics center created for pulse radiolysis with picosecond time-resolution. The facility is a 4-9 MeV electron accelerator using a subpicosecond laser pulse to produce an electron pulse from a Cs2Te semiconductor photocathode and RF gun technology for the electron acceleration. The pulse duration is around 5 ps at low charge (< 2 nC) and high energy (9 MeV), and is under routine conditions 10 ps at higher charge (5 nQ and > 8 McV. The dark current at the target is less than 1% of the pulse photocurrent. Time-resolved absorbance measurements in cells placed in front of the electron beam are achieved using pulsed laser diodes, or a xenon flash lamp as light sources, and photodiodes connected to a 3 GHz transient digitizer or a streak camera (250-800nm range and 3.7ps time resolution) as detection instruments. In addition, the synchronization between the laser beam and the electron beam is exploited to measure the absorbance by a pump-probe set-up, the pump being the electron pulse produced by the laser pulse, and the probe being part of the laser beam (120 fs-3 ps) delayed by a variable optical line. (c) 2006 Elsevier Ltd. All rights reserved.