In the following you will find a selection of open student theses at our chair. Further theses in the mentioned topics are possible on request. Please feel free to contact us!
Please note that there are guidelines (opens in new tab) and LaTeX templates available to help creating presentations, writing reports, Bachelor's or Master's theses.
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Department of Accelerator Physics
Bachelor thesis, Master thesis, HiWi Position
The scientific question is whether a surrogate (low-fidelity) machine model (Fig. 1) can be employed to accelerate a computationally expensive (high-fidelity) finite element machine simulation (Fig. 2).
The research hypothesis is that a well constructed surrogate may perform better than a pure algebraic or stochastic surrogate for standard machine types. It is expected that an established machine model can be trusted in a region which is substantially larger than a standard kriging surrogate of the high-fidelity model. In order to preserve accuracy, the surrogate model will be adapted algebraically such that it locally has at least a linear consistency with the finite-element model [1]. This will be achieved by additive or multiplication defect corrections. In particular, an additive correction with quasi-second-order consistency will be set up using Broyden-Fletcher-Goldfarb-Shanno updates for the Hessian of the high- and low-fidelity models.
Supervisors: Prof. Dr.-Ing. Herbert De Gersem, Max Schaufelberger , M.Sc.
Master thesis
Master thesis, HiWi Position
To improve the simulation of particle dynamics, we couple two types of solvers using a scattered field formulation to solve Maxwell's wave equations in the time domain. Herein, the total electric field E is decomposed into a prescribed incident field E_i and a scattered field E_s. The two are coupled by the PEC-boundary condition which the sum of the two fields (but not each individually) have to fulfill.
The aim of this thesis is to generalize the concept of a scattered field approach to non-perfectly conducting materials at the boundary. When using a single field formulation, one can use surface impedance boundary conditions (SIBC). We want to apply this concept also to the scattered field formulation and implement it into our current simulation code.
The student will gain a broad background in the modeling workflow: How to start from physical equations, how to transfer them to a discrete representation and how to finally implement an effective realization in an existing code framework.
Prerequisites: Strong interest in numerical methods for electromagnetic field computations (PDEs, FIT) and their application. Interest in working with C++.
Feel free to pass by Jonas Christ for more details.
Supervisors: Jonas Christ, M.Sc., PD Dr. rer. nat. Erion Gjonaj
Master thesis
Introduction: Soon the electromotive market will rapidly grow up. One aspect for this growth is the increase of the energy density of high voltage battery systems. This systems are built up with Li-Ion cells with a module voltage up to 850V. To increase the performance of such systems, the inner resistance of the module has to be as small as possible. As a result, the short circuit current of such High Voltage Batteries reaches up to 20kA. To interrupt such a high short circuit current within 2ms the Pyrotechnical Battery Disconnector was developed by Joyson Safety Systems Aschaffenburg GmbH.
Task: Development of an electrodynamic model of a pyrotechnical battery disconnector. Transient nonlinear electrodynamic FE simulations to improve the design of the Pyrotechnical Battery Disconnector.
Supervisor: Prof. Dr.-Ing. Herbert De Gersem
HiWi Position
Pyrit is a Finite Element Method Based numerical field simulation software written in Python to solve coupled systems of partial differential equations. Currently, the modular solver covers static and quasistatic electric and magnetic fields, stationary current problems, stationary, and transient heat conduction problems. The different modules can be coupled to analyze multiphysical engineering applications, such as e.g. foil windings, cable joints, and surge arresters. The software is under continuous development. Thus, developing further parts and maintaining existing parts of Pyrit are the main tasks.
Supervisor: Jonas Bundschuh, M.Sc.
Bachelor thesis, Master thesis, HiWi Position
Currently available linear accelerators are operated in pulsed mode to prevent a thermal overload of the entire system. Upcoming planned CW operations are possible using SRF photoinjectors with either warm or cold photocathodes. The use of warm cathodes in an otherwise cold cavity, which initially appears advantageous, unfortunately leads to a variety of difficulties. On the other side, a cold photocathode cannot be made from the efficient semiconducting materials such that metals with intrinsically lower quantum efficiencies have to be applied instead. Nanostructured surfaces can be used to increase the effective quantum efficiency by surface plasmon resonance enhancement. Optimized nanostructures enable the efficient application of a given laser with a specified wavelength and allow a promising operating regime for future photoinjectors.
Supervisor: Dr.-Ing. Wolfgang Ackermann
Bachelor thesis, Master thesis, HiWi Position
At DESY the currently available electron gun is based on a normal conductive copper cavity operated in pulsed mode. It will be replaced by a superconducting variant to enable also CW operation. The required electromagnetic field in the cavity is then excited by a dedicated input-coupler system originating from the well-known TESLA input power coupler. Additional HOM couplers are not considered in the current design phase but may be added if required. Due to the asymmetric coupling of the resonator fields to the external sources the extracted electron beam will observe a parasitic coupler kick which has to be minimized.
Supervisor: Dr.-Ing. Wolfgang Ackermann
Master thesis
At DESY in Hamburg the particle accelerator PETRA will be equipped with new rf resonators for the acceleration of the particles. For this reason the electromagnetic properties of these cavities have to be investigated. The 3D electric and magnetic fields can be simulated with numeric tools. And these fields need to be evaluated by post processing to calculate the accelerating and deflecting effects on the charged particle beam.
Supervisor: Dr. phil. nat. Wolfgang F.O. Müller
