Arbeitsgruppe Markus Roth
Laser- und Plasmaphysik

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Figure 1: Picture of the Zeiss Versa730 X-Ray CT system the force cell is developed for.
Figure 1: Picture of the Zeiss Versa730 X-Ray CT system the force cell is developed for.

Master Thesis

A key challenge to developing technologies for laser-driven inertial fusion energy is the reliable handling, transport, injection, and characterization of fragile cryogenic fusion targets. KIP together with Focused Energy is developing a compact experimental cell for integration into a ZEISS Versa730 X-Ray CT system. The cell will enable the in-situ investigation of how fusion-target geometries and internal volume properties change under mechanical loads and, in a later development phase, under cryogenic conditions below approximately 18 K. We are looking for a motivated Master’s student who would like to develop and experimentally characterize this system as part of their Master’s thesis.

The precise scope of the thesis will be defined together with the student and the supervisor. It may include deriving the functional and measurement requirements for a force cell to be operated inside an X-Ray CT system, developing a conceptual and detailed design for the experimental cell, and designing mechanical components and assemblies in CAD. The work may also involve developing methods for applying and measuring defined mechanical loads on fragile targets, investigating the compatibility of the system with the ZEISS Versa730 X-Ray CT—including spatial, material, accessibility, and imaging constraints—and building and commissioning a laboratory prototype. In addition, the student may develop experimental procedures for force, temperature, and dimensional characterization, perform measurements to analyze target deformation and changes in internal volume properties, and compare the experimental results with, where appropriate, numerical simulations. A further important part of the thesis will be the systematic documentation of the design, measurement methodology, results, limitations, and recommendations for future development.

This master thesis employs Comsol Multiphysics for numerical simulations, specifically focusing on the transport of DEDs against gravity within a tube (see Figure 1). By inducing shear forces at the interfaces between carrier fluid and shell phase, and subsequently between shell and core phase, we aim to navigate the intricate dynamics of carrier, shell, and core phases. The ultimate objective is to achieve concentric alignment (c = 0 in Figure 1), a critical factor for optimizing fusion energy production. This can be achieved by finding suitable parameters for the velocity of the carrier fluid.

This thesis offers the opportunity to work on a technically challenging project at the interface of fusion technology, precision engineering, cryogenics, and advanced X-Ray imaging. You will be directly involved in designing, constructing, and characterizing a real experimental system and will get the opportunity to get experience with one of the most modern micro CTs existing. You will work closely with a multidisciplinary team at Focused Energy with expertise in target physics, robotics, cryogenics, materials science, and experimental systems. The topic has direct relevance to the development of future laser-fusion power plants and provides the opportunity to contribute to research and development activities with practical technological significance.

We are looking for a student who is currently pursuing a Master’s degree in Physics, Mechanical Engineering, or a closely related field at TU Darmstadt and who has a strong interest in experimental research and interdisciplinary fusion technology. Practical experience in building, commissioning, or characterizing measurement systems is particularly relevant for this thesis, as is the ability to work with mechanical CAD software and create well-structured technical designs. Basic programming skills in Python are expected for tasks such as data processing, analysis, visualization, or experiment automation. The successful candidate should be able to work independently, approach technical challenges in a structured manner, and communicate effectively within a multidisciplinary team. A very good command of English is required; knowledge of German is helpful but not essential.
Experience with force, displacement, temperature, and pressure sensors, or cryogenic systems, vacuum technology, thermal management, and low-temperature measurements are beneficial. Experience with X-Ray CT or other non-destructive characterization methods would be advantageous. Familiarity with measurement uncertainty, calibration, and experimental design, as well as practical experience in a workshop, prototyping environment, machining, or laboratory, would further support the successful completion of the thesis.

Are you interested? For more information, please contact and

Figure 1: Sketch of the physical problem.

Master Thesis

Unlocking the potential of nuclear fusion as a sustainable energy source requires overcoming intricate challenges associated with the direct laser-driven inertial fusion approach. This method entails the simultaneous convergence of laser beams onto a hydrogen-filled hollow sphere, necessitating the generation of high-frequency fusion events within capsules of approximately 2 mm in diameter. To address the precision requirements for sphere production, including stringent quality criteria such as sphericity, concentricity, surface roughness, and wall thickness, the adoption of microfluidics emerges as a transformative solution.

Within the microfluidics paradigm, double emulsion droplets (DEDs) assume a central role, featuring a droplet core phase encapsulated within another droplet (shell phase) within a carrier fluid. The primary challenge lies in the fabrication of solid shells with a uniform wall thickness, corresponding to concentrically aligned core- and shell phase droplets. The existence of different densities in the constituent phases introduces buoyancy forces, which pose a potential disruption to concentric alignment.

This master thesis employs Comsol Multiphysics for numerical simulations, specifically focusing on the transport of DEDs against gravity within a tube (see Figure 1). By inducing shear forces at the interfaces between carrier fluid and shell phase, and subsequently between shell and core phase, we aim to navigate the intricate dynamics of carrier, shell, and core phases. The ultimate objective is to achieve concentric alignment (c = 0 in Figure 1), a critical factor for optimizing fusion energy production. This can be achieved by finding suitable parameters for the velocity of the carrier fluid.

Embark on a scholarly exploration of microfluidics precision, where simulation converges with practical application in the pursuit of a sustainable future for fusion energy.

Are you interested? For more information, please contact and.