Postdoctoral position in Materials Physics with specialization in Simulating and Fitting of Neutron Scattering Data

The research conducted at the Department of Physics and Astronomy encompasses a wide range of physics topics, distributed over nine divisions. The department is located in the Ångström Laboratory and employs nearly 400 people, 100 of whom are doctoral students. It offers a broad physics curriculum to undergraduate and graduate students, participation in nationally and internationally leading projects for researchers, and opportunities for partnership with industry and various outreach activities.

The research within the division of Materials Physics, at Uppsala University, is centred around understanding the physical properties of materials by analysing their structure and composition across multiple length scales, from the atomic to the macroscopic, and linking them to functional properties. Core areas are magnetism, hydrogen, energy materials, soft matter and ion-solid interactions. Read more about the department here: www.physics.uu.se.

The work conducted in the recruiting group within the Materials Physics division is done in collaboration with the two large-scale facilities ISIS and ESS. The ISIS Neutron and Muon Source Facility, in the UK, is a world-leading center for research in the physical and life sciences. The suite of over 30 neutron and muon instruments gives unique insights into the properties of materials on the atomic scale. A national and international community of more than 3000 scientists is supported for research into subjects ranging from clean energy and the environment, pharmaceuticals and health care, through to nanotechnology and materials engineering, catalysis and polymers, as well as fundamental studies of materials. https://www.isis.stfc.ac.uk/

ESS (European Spallation Source) is a partnership organization of 13 European countries, and is located in the city of Lund, Sweden. The project includes the most powerful linear accelerator ever built, 15 state-of-the-art neutron instruments, and a supercomputing data management and software center. It has around 600 employees, and will have first neutrons in 2025, with a start of user operations scheduled for 2027. www.ess.eu/

Duties
We are looking for a scientific researcher with a strong background in software development, or software developer with a strong interest in science. You will join a project, within which applied statistics and information theory is used to quantify the information content of neutron reflectivity datasets. Using this, we are able to optimize the design of experiments and to make previously impossible experiments possible, as well as to run existing experiments faster and better.

Participation and collaboration with all other parts of the project is strongly encouraged and if the candidate chooses, they can participate in the large-scale facility experiments.

The code-base is released as an open-source project (https://github.com/jfkcooper/HOGBEN ), mainly written in Python. Significant development of the capabilities of the code-base is required. These will include improvements to the experimental design code, as well as improving the data analysis, applying Bayesian methods for extracting parameter uncertainties and model selection. The developments will allow the entire collaboration to move forward, suggesting optimal materials systems to be investigated and designing experiments for the other nodes of the project.

The position is based in Uppsala, Sweden but will involve travel to the UK and France, for working at ISIS and ILL. Regular visits to ESS in Lund, Sweden, will be necessary. There will be opportunities for overseas travel to meet international collaborators, to present the work at workshops/conferences and to provide training.

Requirements
PhD degree in physics, materials science, computational physics, computer science or equivalent, or a foreign degree equivalent to a PhD degree in one of these subjects. The degree needs to be obtained by the time of the decision of employment. Priority will be given to applicants who have completed their degree no more than three years before the deadline for applications.  Due to special circumstances, the degree may have been obtained earlier. The three-year period can be extended due to circumstances such as sick leave, parental leave, duties in labour unions, etc.

The following is further required:

• Good computer/programming skills (Python or similar)
• High degree of motivation, good collaboration skills and team spirit
• Excellent language skills in spoken and written English.

Additional qualifications
Solid background in condensed matter physics, e.g., magnetism, are considered an advantage, as is prior knowledge of neutron reflectivity. An eagerness to learn Swedish is assumed for non-Swedish-speaking candidates, and support can be provided.

About the employment
The employment is a temporary position of 2 years according to central collective agreement. Full time position. Starting date 2025-09-01 or as agreed. Placement: Uppsala.

In this recruitment we have replaced the cover letter with questions that you are asked to answer when making your application. The answers will be used as a part of the selection process.

For further information about the position, please contact: Björgvin Hjörvarsson (bjorgvin.hjorvarsson@physics.uu.se, +46 (0) 18 471 3837) eller Jos Cooper (jos.cooper@ess.eu)

Please submit your application by 15 August 2025, UFV-PA 2025/2109.

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