Référence projet : 11-EQPX-0041
RST : Florian BANHART
Etablissement Coordinateur : CNRS Alsace (Strasbourg)
Région du projet : Grand Est
Discipline : 2 - SMI
Aide de l'ANR 3 300 000 euros
Investissement couvrant la période de juin 2012 à décembre 2019
After an extensive planning of the equipment and the restoration of the laboratory infrastructure, the ultrafast transmission electron microscope (UTEM) has been installed in 2014. In 2015, the microscope has been officially accepted and launched. A postdoc and a PhD student were recruited with support from this project. The tests and the optimization of the system in the stroboscopic mode, which is used for studying reversible transformations, took almost one year. After redesigning the optical periphery, a detailed characterization of the electron pulses was carried out. A time resolution of 1 ps, sub-nanometer spatial resolution, and an energy resolution down to 0.8 eV are obtained. However, tradeoffs between these specifications are necessary according to the study to be carried out. A detailed recipe for the adjustement of all system parameters for each technique of operation was established. In 2016, the single-shot setup, which is used for studying irreversible transformations, was designed and installed. The characterization of the electron pulses showed a time resolution down to a few nanoseconds and an energy resolution of 2-5 eV. The latter, needed for electron energy-loss spectroscopy (EELS), can be considered as a breakthrough since it is now shown that, despite contrary predictions, EELS with single nanosecond electron pulses is feasible. Furthermore, a beam deflector system was installed that allows millisecond recording with a continuous electron beam. The microscope is now ready to operate in all modes (stroboscopic pulses, single-shot, and continous beam). The project period 1 (tranche 1), although fiscally extended to the end of 2017, is finished. As part of the second period (tranche 2), scientific projects are now in progress on phase transformations in nanoparticles, photo-switchable hybrid systems, photostrictive materials, and nanomagnetism.
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