arXiv subjects

Paolo Usai

Publications and source records attributed to Paolo Usai.

2 recordsLinked to original sources

arXiv2025

Shot-to-shot acquisition ultrafast electron diffraction

We demonstrate a novel shot-to-shot acquisition method for optical pump - keV electron energy probe in ultrafast scattering experiments. We integrate a phase-locked acquisition scheme at a repetition rate of 20kHz in a conventional ultrafast electron diffraction (UED) setup. We proceed to a full characterization of the noise level in different configurations and for realistic scenarios. The shot-to-shot acquisition improves the signal-to-noise ratio (SNR) by one order of magnitude and can be readily implemented in other high-repetition rate electron diffraction and spectroscopy setups.

physics.ins-det↗

arXiv2024

Revisiting the excitation of the low-lying $^{181\text{m}}$Ta isomer in optical laser-generated plasma

The excitation of the $^{181\text{m}}$Ta isomer in the laser-plasma scenario was claimed to have been observed more than two decades ago. However, the reported experimental findings - and the respective high excitation rate - were later questioned as they could not be reproduced theoretically. The controversy has remained open ever since. In this work, we reinvestigate both theoretically and experimentally the $^{181\text{m}}$Ta nuclear excitation in an optical laser-generated plasma. Experimentally we have found no evidence for such an excitation process as consistently predicted by previous and our theoretical models.

nucl-ex↗