Hero Default
50061319_2 - 2021/WP 4

PhD Student advanced phase retrieval methods for x-ray tom

Start of announcement07.05.2021
End of announcement13.06.2021
Institute or departmentInstitute of Materials Mechanics
Apply nowGo to applicant portal
Applicant managementFrau Knufinke

The Helmholtz-Zentrum Hereon operates an outstation at the Deutsches Elektronen-Synchrotron (DESY) in Hamburg in order to provide access to highly brilliant synchrotron radiation within its German Engineering Materials Science Center (GEMS). At the PETRA III synchrotron radiation source, Hereon jointly operates the High Energy Materials Science Beamline (HEMS, P07), the Imaging Beamline (IBL, P05) and the Nanofocus end station of the Micro- and Nanofocus X-ray Scattering Beamline (MINAXS, P03) along with supporting laboratory instrumentation.

The tomography end stations at IBL and HEMS regularly produce large amounts of challenging 3D and 4D imaging data. For soft tissues or to enhance the intensity signal when the attenuation contrast is low, propagation based or grating interferometric phase contrast imaging techniques are employed. In situ/operando/vivo experiments further impose severe constraints on scan times and X-ray dose. In order to enhance image quality, reduce artefacts, accelerate data acquisition and extend the employed techniques beyond current limitations, advanced phase retrieval methods will be implemented including algebraic, iterative, functional or learning based approaches. Furthermore, we explore combined approaches for phase retrieval and tomographic reconstruction as well as strategies for the optimization of acquisition, processing and analysis of image data.

The advancement of equality at the Helmholtz-Zentrum Hereon goes without saying; in particular, we are striving to increase the percentage of women in the science sector.

Your tasks

  • implementation of advanced phase retrieval methods including learning-based approaches
  • application of developed algorithms to user data from tomography experiments
  • participation in tomography experiments (beamtimes) at our PETRA III beamlines
  • close collaboration with colleagues and beamline staff
  • publish and present scientific results at international conferences and workshops

Collaborative tasks include:

  • mutual optimization of acquisition, processing, and analysis of image data
  • development of combined approaches for phase retrieval, tomographic reconstruction or image processing
  • implementation of image processing tasks (artefact reduction, denoising, movement correction, segmentation, etc.)

Your profile

  • excellent diploma or master’s degree in physics, mathematics, computer science or equivalent
  • experience in X-ray tomography, phase contrast imaging, or image processing of tomography data
  • proficient in a relevant programming language (python, Matlab, C/C++, CUDA, etc.)
  • knowledge in the areas of deep learning
  • team player with good communication skills
  • motivation to work in an interdisciplinary and international team
  • excellent knowledge of English

These qualifications are considered assets:

  • experience with data analysis and handling of large data sets
  • experience in software development
  • experience in high performance, parallel, or distributed computing
  • experience with image enhancement, image segmentation, or image registration
  • experience with working at a synchrotron beamline
  • good communication skills in German

This PhD position is initially limited to 3 years. Informal enquiries can be directed to Dr. Julian Moosmann, julian.moosmann@hereon.de

We offer you

  • multinational work environment with over 1,100 colleagues from more than 50 nations
  • extensive options of vocational training (i. a. expert seminars, language courses or leadership seminars)
  • flexible working hours and various models to ensure the compatibility of family and career
  • excellent infrastructure, including a scientific in-house library as well as modern work spaces
  • remuneration according to the standards of the collective wage agreement TV-AVH including further social benefits
  • Employee Assistance Program (EAP)
  • Welcome office, guesthouses

Severely disabled persons and those equaling severely disabled persons who are equally suitable for the position will be considered preferentially within the framework of legal requirements.


Then we are looking forward to receiving your comprehensive application documents indicating the reference number 2021/WP 4 including cover letter (short, concise, max. 1 page), CV, list of publications, letter of recom­mendation, copies/​transripts of certificates including grades, proof of your English skills (TOEFL, IELTS or equivalent), and (link to) pdf file of your master thesis. The application must not exceed 10 MB.