Postdoctoral researcher in fast neutron dosimetry and reference neutron fields

Would you like to work with fast neutrons, neutron dosimetry and detector characterisation, supported by skilled and friendly colleagues in an international environment? Would you like an employer that invests in sustainable employee relations and offers secure, favourable working conditions? Welcome to apply for a postdoctoral position at Uppsala University.

The Department of Physics and Astronomy is one of Uppsala University’s largest departments, with nearly 400 employees, including approximately 100 doctoral students. The department conducts world-class research and education in both theoretical and experimental physics and has extensive collaboration with the wider community. Research is carried out in ten divisions and covers everything from the unimaginably small to the vast, in areas such as energy supply, climate change, new materials and the universe. This entire spectrum is also reflected in the department’s courses and degree programmes. Around 2,500 students take undergraduate and postgraduate courses at the department each year.

The position is based in the Division of Applied Nuclear Physics. We link fundamental nuclear physics research to applications in nuclear technology and radiation safety. Examples of our research areas include experimental studies of fission, neutron spectrometry for fusion plasma diagnostics, nuclear data evaluation methods, and technical aspects of nuclear safeguards and disarmament. The division operates NESSA, a 14 MeV neutron facility in the FREIA hall at the Ångström Laboratory. Since November 2025, NESSA has been equipped with a DT neutron generator that produces up to 10⁸ neutrons per second, making the facility unique in Sweden and the Nordic countries.

The position is funded by the Swedish Radiation Safety Authority (SSM) as part of the project “A reference neutron field in Uppsala for detector response, dosimetry and cross-calibration in support of radiation protection and preparedness”. The project will establish and characterise a variable-energy reference neutron field in Uppsala, based on 14 MeV neutrons from NESSA and supplemented by neutron fields from charged-particle reactions at the Tandem Laboratory, and link the measurements to the European metrology chain. The results will strengthen national expertise in radiation protection and preparedness.

Duties
You will lead the project’s experimental and computational work as part of the NESSA team:
build and validate Monte Carlo models of the NESSA bunker and detectors using several codes, e.g. MCNP, FLUKA, Geant4, PHITS and FISPACT-II,
commission and use a detector array comprising, for example, liquid scintillators with pulse-shape discrimination, micro fission chambers, and activation foils analysed using HPGe gamma spectrometry,
characterise neutron fields in terms of energy spectrum and fluence, with complete uncertainty budgets,
conduct shielding and moderation experiments (e.g. polyethylene and concrete) and compare the results with simulations,
measure detector response functions in neutron fields at the Tandem Laboratory in Uppsala,
plan and carry out a cross-calibration campaign at a reference neutron field (e.g. PTB in Braunschweig),
publish results in scientific journals and at international conferences,
contribute to training in neutron measurement techniques for students and staff from government agencies and industry.

We also encourage you to develop your own research profile and contribute to applications that help develop the division’s activities.

Qualification requirements
A PhD in physics or a related subject, or a foreign degree considered equivalent to a PhD in physics or a related subject. The degree must have been completed by the time the appointment decision is made. Preference will be given to applicants who completed their degree no more than three years ago. The three-year period is calculated from the application deadline. The degree may have been completed earlier if there are special circumstances. Special circumstances include leave due to illness, parental leave, trade union duties, etc.

You must have documented experience in experimental nuclear or radiation physics, for example neutron measurements, radiation detectors or dosimetry, as well as experience in Monte Carlo simulation of radiation transport. You must have an excellent command of spoken and written English. We are looking for someone who is organised and meticulous, can work independently and drive an experimental project forward, and works well with others.

Desirable/other qualifications
The following are considered merits but are not requirements, and we strongly encourage you to apply even if your experience does not cover all the qualifications listed:
Experience with experimental techniques involving fast neutrons.
Experience with liquid scintillators with pulse-shape discrimination, fission chambers or digital data acquisition.
Experience in neutron spectrometry and neutron dosimetry, e.g. Bonner sphere spectrometry and spectrum unfolding methods.
Experience with neutron activation methods and HPGe gamma spectrometry.
Good knowledge of one or more of the codes MCNP, FLUKA, Geant4, PHITS and FISPACT-II.
Experience in uncertainty analysis and metrology.
Experience with experiments at accelerators or other neutron sources.

Terms of employment
The position is fixed-term for 2 years under a central collective agreement (kollektivavtal). The position is full-time. Starting date: 1 February 2027 or as agreed. Location: Ångström Laboratory, Uppsala.
For information about the position, contact: Stephan Pomp, +46-70-167 9003, stephan.pomp@physics.uu.se.

For this recruitment, we have replaced the cover letter with questions for you to answer as part of your application. Your answers will be used as part of the selection process. Please attach a copy of your doctoral degree and your course grades to your application.

Welcome to submit your application by 7 December 2026, UFV-PA 2026/3137.

Please note that this is an abbreviated version of the advertisement. To see the full advertisement, please click “Apply here” or visit Uppsala University’s jobs website.