ALTAïS - Penetrating the depths of matter to meet today's challenges

This article was produced for the "Eureka" section of Omalius magazine #36, March 2025.

Capable of generating ion beams consisting of any stable element with energies of up to 16 Mega electron-Volt (MeV), the particle gas pedal enables the analysis (IBA) and modification (IBMM) of thin films of many materials. Stimulated by the critical need for new functional materials, the development of these techniques has accelerated in the 21st century. They are essential in many areas of fundamental research, and are also used in applied research, through industrial partnerships.

Tijani Tabarrant's role is essential to ensure the smooth running of this complex equipment. He is responsible for its maintenance to ensure continuity in research. At the same time, he makes a significant contribution to the research by designing and developing various vacuum chambers, which are crucial to our experiments. To carry out these projects, he works closely with the mechanical workshop, whose expertise and resources are indispensable.

The strength of IBMM (Ion Beam Modification of Materials) is its ability to modify the electronic, optical, mechanical or magnetic properties of various materials in a controlled way. This is known as "functionalizing materials".

IBA (Ion Beam Analysis) is a family of non-invasive, highly versatile analysis techniques for studying the chemical composition of materials. It has played a leading role for decades in nuclear astrophysics, materials science, life sciences and even heritage and archaeological sciences.

In microelectronics, ion implantation, essential for doping semiconductors, is a key stage in the manufacture of electronic chips. The IBA makes it possible to analyze the presence of these dopants, as well as that of hydrogen, an element that can influence the lifespan of electronic components.

In nuclear energy, ion beam irradiation makes it possible to simulate the effects of radiative damage on materials used for nuclear fuel cladding or radioactive waste storage. In this way, their long-term durability can be assessed.

In the aerospace field, ion beam irradiation is used to test the resistance of space materials to cosmic radiation, improving the design of satellites and spacecraft.

For hydrogen production and storage, the IBA helps design anti-diffusion coatings. Hydrogen is a tiny atom that diffuses easily through materials. Hydrogen storage is a key issue for the energy transition.

In everyday life, telephone screens, windscreens and even windows benefit from surface treatments that modulate their opacity, as well as their anti-scratch, anti-reflective or anti-smudge properties. These effects are achieved through the synthesis and optimization of thin surface layers, in collaboration with the glass industry. The IBA enables the characterization of these thin films, which helps in the development of new functionalities.

One of ALTAïS's terminal stations is dedicated to studying the response of cells to radiation (protons, helium, carbon).

Thus, researchers can carry out studies on:

• the generation of radioresistant cancer cells and the development of strategies to re-sensitize them,
• the involvement of mitochondria in resistance to radiotherapy;
• the influence of membrane lipid composition on the response to radiotherapy treatment

They are studying the FLASH effect - very high dose rate irradiation - on a worm C. elegans. The FLASH effect not only maintains tumor control but also spares healthy tissue, which is of key importance in tumor treatment.

They are also reprogramming immune system cells with gold nanoparticles and ionizing radiation (X-ray or proton).

At UNamur's Department of Physics, Professor Guy Demortier, was one of the pioneers in the use of IBAs to characterize ancient objects or fossils. These analyses help to determine the manufacturing methods and provenance of the materials used to make historical artefacts, as is the case at the AGLAE laboratory, based in the Louvre museum, which carries out this type of analysis on a daily basis. Analysis of the coloration of natural geological objects (e.g. speleothems) also provides its share of information about the evolution of the climate and environment of a particular geological area.

With the recent arrival of Professor Julien Colaux, a new impetus has been gained and is part of a broader perspective.

The ALTAïS gas pedal is part of the state-of-the-art equipment of the SIAM (Synthesis, Irradiation and Analysis of Materials) technology platform.

Researchers from the NISM Institutes, NARILIS and ILEE use it daily to push back the boundaries of the unknown. The Department also hosts practical work activities by physics and biology students.

Building on their long experience in functional (nano)materials, microelectronics, photovoltaics, batteries, life sciences and heritage sciences, the multidisciplinary teams of researchers are key players in the understanding of matter in the fundamental sense, physical interactions on the atomic scale and the development of new technologies applied to today's global challenges.