Postdoc position: Controlling splashing and debris from solidifying tin droplets

Postdoc position:
Controlling splashing and debris from solidifying tin droplets

ARCNL is a new type of public-private partnership between the University of Amsterdam, the VU University Amsterdam, the NWO, and ASML.

Work Activities
This experiment-oriented postdoctoral position lies at the interface of fluid mechanics, phase-change physics, and industrial application. It is part of ARCNL’s Source Department and the EUV Plasma Processes group. We investigate the fundamental dynamics of liquid-tin targets and plasmas that underpin present and future extreme-ultraviolet (EUV) light sources for nanolithography. This project is carried out in close collaboration with industry.
Our group combines precision experiments, advanced imaging, and modeling to uncover the physics of tin droplets under extreme conditions of laser irradiation. We have established a strong track record in laser-droplet interaction, droplet deformation, and fragmentation physics. Our recently published works include laser-driven sheet formation and propulsion, curvature inversion in thin films, transitions between droplet oscillation and breakup, and singular jetting in free-falling droplets [e.g. J.

Fluid Mech. 1020, A21 (2025); J. Fluid Mech. 1034, A26 (2026);
Phys. Rev. Fluids 11, 073602 (2026)].
This project builds directly on that expertise to uncover how rapid solidification governs splashing, adhesion, and debris formation when molten-tin droplets impact solid substrates.

Background
Molten droplets impacting colder surfaces are encountered in applications ranging from EUV lithography to metal additive manufacturing and droplet-based printing. During impact, inertial spreading, capillary retraction, heat transfer, and solidification can occur on comparable timescales. Depending on impact conditions and surface properties, the droplet may adhere, rebound, splash, freeze, peel from the surface after solidification, or break up into smaller secondary droplets.
Although droplet splashing and solidification during impact have each received substantial attention, their strongly coupled dynamics under reduced ambient pressure remain insufficiently understood. Establishing which physical mechanisms, dimensionless parameters, and scaling laws remain valid across these scales is therefore both a fundamental and technologically relevant problem.

Project goal
The project aims to develop a predictive, experimentally grounded understanding of how rapid solidification and ambient pressure shape molten-tin droplet impacts, and to use this insight to identify surfaces and operating conditions that minimize splashing and debris formation. You will start from a droplet-on-demand platform for millimeter-sized molten-tin droplets, with systematic control over ambient pressure, substrate temperature, impact velocity, and surface properties, combined with synchronized high-speed side- and bottom-view imaging.
You will establish quantitative regime maps for spreading, sticking, rebound, freezing, peeling, and fragmentation. Using existing image-analysis tools and newly developed workflows, you will quantify droplet deformation, contact-line motion, solidification dynamics, and the size and velocity distributions of secondary droplets. These measurements will form the basis for predictive scaling relations that describe fragment formation across pressure and temperature conditions.
Together with collaborators at TU/e and UvA, and through interaction with industrial partners, you will translate the resulting physical understanding into practical design principles for low-debris surfaces and operating windows in advanced EUV source environments.

Qualifications

• You have (or will soon obtain) a PhD in (Applied) Physics, Mechanical Engineering, Chemical Engineering, Materials Science, or a closely related field.
• You have a strong experimental background and enjoy designing, building, and improving laboratory experiments.
• Experience in one or more of the following areas is an asset: fluid dynamics, droplet impact, multiphase flow, heat transfer, phase change, high-speed imaging, vacuum systems, optical diagnostics, or surface science.
• Experience with scientific programming and quantitative data analysis, particularly in Python, is welcomed.
• Experience with droplet generation, thermal diagnostics, image processing, or automated experimental control would be advantageous, but is not required.
• Strong verbal and written communication skills in English are required, together with enthusiasm for…