Develop fundamental wavefield analysis methods to improve imaging and monitoring for subsurface exploration, medical imaging, and structural health monitoring.

Job description
We are looking for a PhD candidate who is keen to engage with fundamental problems in wavefield analysis to improve current methods for imaging and monitoring with a broad range of applications that tackle the challenges of a changing climate and society: How can we sustainably heat as many homes as possible? Where shall we establish the next hydrogen storage reservoir? What can we do to monitor the health of structures in a non-destructive way? How can we optimise ultrasound imaging for breakthroughs in medicine and patient care?

Wave-based imaging techniques are used to minimise uncertainties and help to inform decision-making. However, a fundamental but still unresolved problem is caused by the presence of multiply scattered waves, which cause noise in standard imaging methods. Several approaches exist to identify and attenuate these waves, but their limitations often mean also damaging the desired primary (single-scattered) signal. Over the last two decades, a revolutionary way of seeing and processing seismic wavefields evolved with a set of methods commonly referred to as “seismic interferometry”. Inter-receiver interferometry has become famous for “turning noise into signal” by cross-correlating ambient noise data on two receivers and thereby creating a seismic signal (a Green’s function estimate) as if one of the receivers had been an active source. A more advanced form called source-receiver interferometry (SRI) provides a means to construct specific parts of a seismic signal, allowing us to identify all multiply-scattered waves in active-source seismic reflection data by predicting their arrival times. Preliminary research has shown the potential of SRI to also quantify the scattering strength and resulting signal amplitude for simple scattering media.

A related technique, coda-wave interferometry allowed tiny changes in wave velocities to be monitored by analysing the coda (the late arriving, multiply scattered part) of active as well as passive-source signals. While this technique became popular to identify temperature or fluid-related variations in the background velocities of scattering media, the scattering properties themselves and changes thereof have not yet received the same attention. If (changing) scattering amplitudes can be measured and interpreted correctly, acoustic monitoring of carbon stocks stored in forests, or changes in scattering properties of tissue within the human body, could be promising applications.

The goal of this PhD is to further explore the theories of source-receiver and coda-wave interferometry in scattering media for the purpose of true-amplitude prediction of multiply scattered or reflected waves. After familiarising yourself with the principles of seismic interferometry and scattering theory, you will expand the existing theory to increasingly more complex models and validate new concepts by developing and using numerical modelling of scattering in simple models, eventually testing your approach on more complex synthetic (computationally modelled), as well as real acoustic or seismic data. We encourage you to develop and explore your own research ideas as well as ours following new discoveries and insights, and will provide you with the necessary freedom and support to do so.

Job requirements
Being creative and independent, you enjoy working on theoretical problems and are confident to master the challenges of organising a complex research project.

You also have:

• an MSc in a relevant field, such as physics, geophysics, or applied mathematics,
• interest in wave propagation phenomena and imaging methods,
• experience in scientific programming (preferably in Python or Matlab).

Experience in one or more of the fields below is considered an advantage:

• seismic methods (e.g., interferometry), ultrasound, scattering theory, or signal processing,
• (finite-difference) wave propagation modelling,
• scientific writing and presentation.

TU Delft
Delft University of Technology is built on strong foundations. As creators of the world-famous Dutch waterworks and pioneers in biotech, TU Delft is a top international university combining science, engineering and design. It delivers world class results in education, research and innovation to address challenges in the areas of energy, climate, mobility, health and digital society. For generations, our engineers have proven to be entrepreneurial problem-solvers, both in business and in a social context.

At TU Delft we embrace diversity as one of our core values and we actively engage to be a university where you feel at home and can flourish. We value different perspectives and qualities. We believe this makes our work more innovative, the TU Delft community more vibrant and the world more just. Together, we imagine, invent and create solutions using technology to have a positive impact on a global scale. That is why we invite you to apply. Your application will receive fair consideration.

Challenge. Change. Impact!

The Faculty of Civil Engineering & Geosciences
The Faculty of Civil Engineering & Geosciences (CEG) is committed to outstanding international research and education in the field of civil engineering, applied earth sciences, traffic and transport, water technology, and delta technology. Our research feeds into our educational programmes and covers societal challenges such as climate change, energy transition, resource availability, urbanisation and clean water. Our research projects are conducted in close cooperation with a wide range of research institutions. CEG is convinced of the importance of open science and supports its scientists in integrating open science in their research practice. The Faculty of CEG comprises 28 research groups in the following seven departments: Materials Mechanics Management & Design, Engineering Structures, Geoscience and Engineering, Geoscience and Remote Sensing, Transport & Planning, Hydraulic Engineering and Water Management.

Click here to go to the website of the Faculty of Civil Engineering & Geosciences.

Conditions of employment
Doctoral candidates will be offered a 4-year period of employment in principle, but in the form of 2 employment contracts. An initial 1,5 year contract with an official go/no go progress assessment within 15 months. Followed by an additional contract for the remaining 2,5 years assuming everything goes well and performance requirements are met.

Salary and benefits are in accordance with the Collective Labour Agreement for Dutch Universities, increasing from € 2872 per month in the first year to € 3670 in the fourth year. As a PhD candidate you will be enrolled in the TU Delft Graduate School. The TU Delft Graduate School provides an inspiring research environment with an excellent team of supervisors, academic staff and a mentor. The Doctoral Education Programme is aimed at developing your transferable, discipline-related and research skills.

The TU Delft offers a customisable compensation package, discounts on health insurance, and a monthly work costs contribution. Flexible work schedules can be arranged.

For international applicants, TU Delft has the Coming to Delft Service. This service provides information for new international employees to help you prepare the relocation and to settle in the Netherlands. The Coming to Delft Service offers a Dual Career Programme for partners and they organise events to expand your (social) network.

Additional information
You will be part of the section Applied Geophysics & Petrophysics in the Department of Geosciences & Engineering, Faculty of Civil Engineering & Geosciences, TU Delft. Additional expertise and co-supervision will be provided by academic partners at the University of Edinburgh (UK) and in industry (the Delphi consortium and Quantairra Research & Development Services B. V.). During regular meetings you will have lots of opportunities to network and connect with fellow PhD candidates and other researchers in Delft and beyond. Our department promotes a diverse working environment as well as healthy, family-friendly working hours. We strongly encourage and support all PhD candidates to publish their research in peer-reviewed journals and to actively participate in scientific conferences and workshops. These experiences will pave the way for diverse career paths in research institutes, governmental agencies, industry, (environmental, medical, or construction) consultancy, or academia.

For more information about this vacancy, please contact Dr Katrin Löer at k.loer@tudelft.nl.     

Application procedure
Are you interested in this vacancy? Please apply no later than 19 Jan 2025 via the application button and upload the following documents:

• CV (including a list of relevant courses, the topic of your MSc thesis and contact details of two referees we can call for feedback).
• Motivational letter (max 1 A4, outlining your interest in persuing a PhD and your interest in this particular project.

You can address your application to Dr Katrin Löer.

Doing a PhD at TU Delft requires English proficiency at a certain level to ensure that the candidate is able to communicate and interact well, participate in English-taught Doctoral Education courses, and write scientific articles and a final thesis. For more details please check the Graduate Schools Admission Requirements.

Please note:

• You can apply online. We will not process applications sent by email and/or post.
• A pre-employment screening can be part of the selection procedure.
• For the final candidates, a knowledge security check will be part of the application procedure. For more information on this check, please consult Chapter 8 of the National Knowledge Security Guidelines. We carry out this check on the basis of legitimate interest.
• Please do not contact us for unsolicited services.