Pump-probe experiments at the TEMPO beamline using the low-α operation mode of Synchrotron SOLEIL

The SOLEIL synchrotron radiation source is regularly operated in special filling modes dedicated to pump-probe experiments. Among others, the low-α mode operation is characterized by shorter pulse duration and represents the natural bridge between 50ps synchrotron pulses and femtosecond experiments. Here, the capabilities in low-α mode of the experimental set-ups developed at the TEMPO beamline to perform pump-probe experiments with soft X-rays based on photoelectron or photon detection are presented. A 282kHz repetition-rate femtosecond laser is synchronized with the synchrotron radiation time structure to induce fast electronic and/or magnetic excitations. Detection is performed using a two-dimensional space resolution plus time resolution detector based on microchannel plates equipped with a delay line. Results of time-resolved photoelectron spectroscopy, circular dichroism and magnetic scattering experiments are reported, and their respective advantages and limitations in the framework of high-time-resolution pump-probe experiments compared and discussed.The low-α operation mode of SOLEIL is presented and gives the operation details for experiments using soft X-rays at the TEMPO beamline. Experiments are presented to give the reader the possibility to evaluate the performances of the installation. With the increasing research activity using time-resolved experiments it should be interesting for the synchrotron radiation community. It is thought that the low-α mode operation is the natural bridge between the usual time scale of synchrotron pulses and laser-driven femtosecond experiments.