Measurement of Multi-Photon Absorption in Simple Ionic Systems – Report of the Beam Time of HILITE @ FLASH in 2020

The determination of photo-ionisation cross sections of atoms and ions in highly intense laser fields is challenging both experimentally and theoretically. This is mainly due to the multitude of processes that occur at the same time and are difficult to disentangle. To mitigate this drawback, we have built the HILITE setup. It combines the techniques available in a Penning trap such as the storage, cooling and positioning of pure ionic laser targets with the possibility to superimpose an intense laser field and study the ionisation effects by comparing the trap content before and after the laser interaction. In this presentation I will mainly focus on the first real-world commissioning of HILITE @ FLASH @ DESY, a free-electron laser system, discuss the lessons learned, and give an outlook to upcoming improvements of the setup and future beam-time prospects.