Dr. Kasra Amini
Max-Born-Institut Berlin
will speak on the topic
High repetition rate ultrafast electron diffraction with direct electron detection
Abstract:
Ultrafast electron diffraction (UED)[1] is a powerful tool that can monitor the nuclear dynamics of photo-induced gas-phase reactions in real-time with picometre and 106 electrons/s). Latest results from our pump-probe UED instrument are presented (see Fig. 1c-f) with details of the current implementation of radiofrequency compressed electron pulses. We show that operating with 102 electrons provides very good electron beam properties (transverse coherence length of 8.9 nm, FWHM diameter at sample of 100-µm), with General Particle Tracer simulations (GPT) predicting that the FWHM electron pulse duration of uncompressed (~300-fs; Fig. 1b) and compressed (~35-fs; Fig. 1c) electrons are suitable for the studying a wide-range of photochemical reactions, some of which were so far too fast to be studied with UED. Temporal compression of electrons is achieved using a radiofrequency (RF) field. We have corrected the RF-laser timing jitter of 380-fs to 13.5-fs. Work is on-going on characterising electron compression. In the near future, we will upgrade our set-up for gas-phase studies and we will implement a new, 40-kHz OPA laser system (80-W, 2-mJ).
[1] K. Amini, A. Rouzée, M. J. J. Vrakking, Royal Society of Chemistry, 25 (2023). [
2] F. R. Diaz, M. Mero, K. Amini, Structural Dynamics 11, 054302 (2024).
Interested parties are cordially invited
Professor Dr. Bauer
When: 17.12.2024 14:00
Where: Institute of Physics, Lecture Hall 2