Prof. Dr. rer. nat. habil. Winfried Petry

Courses and Dates

Offered Bachelor’s or Master’s Theses Topics

Implementation of region-of-interest mode in diffraction computed tomography

Implementation of region-of-interest mode
in diffraction computed tomography

Since its development, X-ray tomography became a non-alternative tool for fast and non-destructive characterisation of different objects providing an in-depth resolved information from the interior of materials, devices and living organisms. Besides the overall popularity and the widley use of the method it suffers heavily from contrast limitation issues, which are directly related to the underlying properties of X-ray attenuation. One of the approaches to enhance the sensitivity of the method (at least in the field of solid-state applications) is the utilization of a diffraction-based input signal instead/together with the absorption-based signal information. X-ray diffraction radiography – a scanning technique taking XRD pattern at each scanning position\pixel (and tomography, as its logical continuation) is a relatively new method for sample characterisation, which requires requiring a large amount of diffraction data as input. However, it is capable to provide unique information about the organisation and composition of the studied objects. The size of diffraction data in a XRD-CT dataset is one of the limiting factors for the resolution of the measurement, i.e. for larger samples. A possible solution for this would be a limitation to certain region-of-interest within the objects volume. Thus, the aim of the proposed thesis is the validation of available approaches for reconstruction of XRD-CT data in the region-of-interest mode and its application for non-destructive studies of cylindrical Li-ion batteries.

Common supervision is foreseen with Dr. Anatoliy Senyshyn, diffraction group leader at MLZ.

suitable as

• Master’s Thesis Applied and Engineering Physics

Supervisor: Winfried Petry

Optically controlled automatic sample positioning system for scattering/diffraction applications: conceptualisation and development

Accurate, controllable and reproducible sample positioning is necessary for a variety of experimental techniques utilizing laser, X-rays, electron beams and/or neutrons. For the diffractometers at the FRM II neutron source a fully automatic sample positioning system is required, which, in conjunction with a robotic sample changer, will be the base for an automatized experimental pipeline. The mechanical core of the system will be a stepper motor driven goniometer head from Huber, possessing five degrees of freedom. The movement, detection and control will proceed by a silhouette detection system based on telecentric optics. The tasks of the proposed thesis will include: conceptualisation and building up of telecentric optical control system, the optimisation of data readout, the development of fully automatic alignment algorithm, the integration of the components into NICOS system (Python driven) and the validation of the system in real measurements with neutron scattering and/or synchrotron radiation. Common supervision is foreseen with Dr. Anatoliy Senyshyn, diffraction group leader at MLZ.

suitable as

• Master’s Thesis Applied and Engineering Physics

Supervisor: Winfried Petry

Quantification of local aging behaviour in lithium-ion batteries

Quantification of local aging behaviour in lithium-ion batteries

Lithium-ion batteries are nowadays the primary energy storage system in electric driven vehicles and portable electronic devices. Thus, a continuous improvement of lithium-ion batteries is mandatory to meet the increasing energy demand on the market. One of the main branches of today’s research deals with the minimization of aging effects occurring in lithium-ion batteries and taking place during cell operation. In the proposed project, the state-of-health at different areas of a working electrode in real lithium-ion batteries will be determined in order to create a 2D “map” of the state of fatigue distribution. Thus, commercially available lithium-ion batteries will be electrochemically cycled and disassembled in order to harvest the electrode materials. Fragments of the extracted electrodes collected at various positions over the electrode sheets will be analysed as coin cells with various characterization techniques, such as impedance spectroscopy, cycling voltammetry and galvanostatic intermittent titration technique. The project will be completed with X-ray diffraction measurements of the collected electrodes.

Common supervision is foreseen with Dr. Anatoliy Senyshyn, diffraction group leader at MLZ.

suitable as

• Master’s Thesis Applied and Engineering Physics

Supervisor: Winfried Petry