PhD Position: Deep learning for phase-contrast synchrotron X-ray tomography

Helmholtz Imaging; Indiana (PA); On-site; USD 48,348 - 62,162; Full time

Benefits offered by this job

Corporate benefits

6 weeks holiday per year

Job summary

Helmholtz-Zentrum Hereon in Hamburg, at DESY and PETRA III beamlines, seeks a PhD candidate for learning-based phase retrieval in near-field holotomography. The project combines machine learning, high-performance computing, and synchrotron experiments to develop physics-informed self-supervised methods and multi-scale reconstruction strategies.

Ideal candidates hold a Master’s in physics, mathematics, or computer science, with strengths in image processing, tomography, and Python programming.

Qualifications

• Master’s degree in physics, mathematics, computer science, or a related field.
• Strong analytical skills and a solid theoretical background.
• Experience in machine/deep learning and image processing/tomography.
• Advanced programming skills in Python.
• Excellent command of English (written and spoken).

Responsibilities

• Develop physics-informed, self-supervised learning approaches for phase retrieval.
• Implement reconstruction algorithms on HPC clusters for large-scale hierarchical tomography.
• Apply algorithms to experimental tomographic data.
• Collaborate closely with beamline scientists and project partners.
• Publish and present results in international journals and conferences.

Skills

Machine learning

Image processing

Python

Tomography

Education

Master’s degree in physics

Tools

HPC clusters

Job description

• corporate benefits

Helmholtz Zentrum Hereon operates an outstation at DESY in Hamburg, providing access to highly brilliant synchrotron radiation through its German Engineering Materials Science Center (GEMS). At the PETRA III synchrotron radiation source, Hereon jointly operates several beamlines. Its imaging beamlines offer advanced micro- and nano-tomography techniques with a strong focus on material science and life science applications. The micro-tomography setups cover a wide energy range and offer unique phase contrast capabilities. The full-field nano-tomography setup is among the fastest worldwide due to its unique geometry and beam characteristics. Additionally, the highly coherent beam enables advanced phase contrast methods such as near-field holography.

This position is limited to 3 years and starts as soon as possible. Equal opportunity is an important part of our personnel policy. Hereon would therefore strongly encourage qualified women to apply for the position.

This PhD position is part of the ErUM-Data project CmarT, which aims to develop a novel multi-scale imaging approach at synchrotron radiation facilities, particularly PETRA III at DESY. Biological and materials science samples often exhibit hierarchical structures that determine their function. However, scanning an entire sample volume at the highest spatial resolution is not feasible. Therefore, we need an imaging scheme that captures relevant features at different length scales and integrates them into a single reconstruction volume.

This PhD project focuses on learning-based phase retrieval in the weak holographic regime, bridging the gap between micro- and nano-tomography. While propagation-based phase-contrast imaging enhances visualization of soft tissues and weakly attenuating samples, phase retrieval in this regime remains challenging, limiting multi-scale imaging approaches in near-field holotomography. To address this, the PhD project combines machine learning, high-performance computing, and synchrotron-radiation experiments. The goal is to explore physics-informed self-supervised learning approaches (e.g., deep image priors, GANs) and iterative methods, combined with multi-scale tomography and local adaptive reconstruction to overcome these challenges.

Your tasks

• develop physics-informed, self-supervised learning approaches for phase retrieval
• implement reconstruction algorithms on HPC clusters for large-scale hierarchical tomography
• apply algorithms to experimental tomographic data
• collaborate closely with beamline scientists and project partners
• publish and present results in international journals and conferences

Your profile

• Master’s degree in physics, mathematics, computer science, or a related field
• strong analytical skills and solid theoretical background
• experience in machine/ deep learning and image processing/ tomography
• advanced programming skills in Python
• excellent command of English (written and spoken)

Assets

• team-oriented mindset with strong communication and organizational skills
• experience with HPC clusters, parallel or distributed computing
• German language skills

What Hereon Offers

• a cutting-edge research environment at PETRA III imaging beamlines
• collaboration with leading institutions in imaging, mathematics, and data science
• access to high-performance computing (HPC) resources and advanced experimental setups
• an exciting and varied job in a research centre with around 1,000 employees from more than 60 nations
• a well-connected research campus (public transport) and best networking opportunities, subsidy for the Deutschlandticket if certain conditions are met (job ticket)
• individual opportunities for further training
• social benefits according to the collective agreement of the public service and remuneration up to pay group 13 according to TV EntgO Bund
• an excellent technical infrastructure and modern workplace equipment
• 6 weeks holiday per year; company holidays between Christmas and New Year’s Day
• very good compatibility of private and professional life; offers of mobile and flexible work
• free assistance program for employees (EAP)
• corporate benefits

Helmholtz-Zentrum Hereon

The Helmholtz-Zentrum Hereon conducts cutting-edge international research for a changing world: Around 1,000 employees contribute to the tackling of climate change, the sustainable use of the world’s coastal systems and the resource-compatible enhancement of the quality of life. From fundamental research to practical applications, the interdisciplinary research spectrum covers a unique range.

Institute of Materials Physics

The Institute of Materials Physics operates instruments on large-scale equipment for structural investigations of materials and works on the development and characterization of novel lightweight materials for high-temperature applications, for example in aircraft turbines and automotive engines. Hereon has a unique infrastructure for complementary materials research with photons and neutrons.