Ronnie Hoekstra gives keynote presentation at ICPEAC in Japan
During the first week of August, the 34th International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC) was held in Sapporo, Japan. Ronnie Hoekstra, leader of the Ion Interactions group at ARCNL and University of Groningen, gave one of five keynote presentations at the conference. This was the first time in more than 25 years that a researcher from the Netherlands was a keynote speaker at ICPEAC.
Worlds collide at collisions conference
In a keynote presentation titled “The wondrous world of ions in EUV light sources for photolithography,” Ronnie Hoekstra shared his group’s research at the International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC) in Sapporo, Japan. ICPEAC is the largest conference on collision physics in the world, now welcoming around 650 participants.
“Fun fact: in the 70s and 80s, AMOLF, where ARCNL started, was one of the leading institutes in organizing ICPEAC,” shares Ronnie. Held nearly every two years since 1958, ICPEAC has long been part of the collision physics community.
The conference brought together researchers from all over the world, hosting five plenary speakers from Japan, France, the United States, and the Netherlands. Ronnie was the first plenary speaker from the Netherlands in over 25 years, and it seems that the organization is enthusiastic to involve him further.
A new conference chair
The coming editions of ICPEAC will involve a new role for Ronnie Hoekstra, who has been chosen as the chair of the executive committee for the 2029 edition in Changchun, China. In the meantime, he will also serve on the committee as incoming chair in 2027 in Hamburg, Germany, and later as outgoing chair in 2031 in Vienna, Austria.
Ronnie’s appointment is an honor for both ARCNL and University of Groningen, strengthening our collaboration within the collision physics research community.
The wondrous world of ions
Ronnie Hoekstra leads the Ion Interactions group at ARCNL, exploring the atomic-scale physics of charged tin atoms interacting with gases and metal surfaces. This leads to a better understanding of what happens inside of an extreme ultraviolet (EUV) light source, which uses liquid tin. In the process of producing EUV light, charged tin atoms are released, which can interfere with the metal surfaces of the optics that direct the light out of the source devices. To counter this, source devices contain hydrogen gas to stop the tin ions from reaching the optics. Studying the ion interactions between tin, hydrogen gas, and EUV optics surfaces gives insight not only into the fundamental physics of ion interactions, but also into the development of more efficient EUV light sources.
More information
Visit the ICPEAC 2025 website for more about the conference.
