Studierende finden an der ETH Zürich ein Umfeld, das eigenständiges Denken fördert, Forschende ein Klima, das zu Spitzenleistungen inspiriert.
Seismic waves allow us to image the Earth's sub-surface. This approach, originating in the field of exploration geophysics, is also gaining an increased interest in the sub-surface characterization of planetary bodies in our solar system. A shortcoming of seismic imaging is that the resolution is limited by the number of sensors, due to a signal processing principle known as the sampling theorem. While it may be relatively straightforward in Earth-based applications to add more sensors to obtain better images, deploying large-sensor arrays on the Moon or Mars is not. This forces us to think of ways to obtain the most information out of a sparse network of available sensors.
The Institute of Geophysics is looking for a PhD student. We are flexible with respect to the starting date but it should be no later than September 2023.
One potential approach around the sampling theorem is so-called generalized sampling. In generalized sampling, we compensate for the lack of recording locations by using information on the spatial derivatives of the seismic wave field. A ‘gradiometric sensor’ is a device capable of measuring such spatial derivatives. However, being a novel approach, there are no established designs for gradiometric sensors. We want to solve this shortcoming using metamaterials — novel structures that present advanced wave control capabilities due to their precisely-controlled microstructure. Metamaterials can focus the sound at very small locations, route waves around objects or expand horizontally when elongated. In this project, we will use these properties to make gradiometric sensors, by designing a metamaterial structure so that it passively senses (combinations of) spatial derivatives of the seismic wave field. The derivatives will be converted to an electrical signal using a custom-made Micro Electro Mechanical System (MEMS) transducer.
In the Exploration and Environmental Geophysics (EEG) group at ETH Zürich, we are recruiting a PhD student to design, fabricate and test gradiometric sensors, based on mechanical metamaterials. You will involve a combination of theory and experiments. The theory work will comprise computer optimization of the sensor design whereas the experimental part will consist of the fabrication and characterization of the sensor. For fabrication, we will employ a combination of 3D printing and cleanroom-based microfabrication, and for characterization, we will use laser doppler vibrometry on a sandbox setup for instance containing lunar regolith simulant.
This project has a strong international component. You are expected to spend one year at AMOLF (Amsterdam) working on the sensor/metamaterial design, and several months at EPFL in Lausanne for device fabrication. The home base will be at the Centre for Immersive Wave Experimentation (CIWE) at ETH Zurich, where the laser/sandbox characterization setup is located. The resulting concept sensor will be part of a proposal for a lunar mission expected to take place in 2026.
ETH Zurich is a family-friendly employer with excellent working conditions. You can look forward to an exciting working environment, cultural diversity and attractive offers and benefits.
We look forward to receiving your online application by 28.02.2023 with the following documents:
Please note that we exclusively accept applications submitted through our online application portal. Applications via email or postal services will not be considered.
Further information about the Institute of Geophysics and the Exploration and Environmental Geophysics group can be found on our . Questions regarding the position should be directed to Prof. Johan Robertsson, Prof. Marc Serra-Garcia, and Dr. Dirk-Jan van Manen, email: firstname.lastname@example.org (no applications).
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