The Institute of Space Physics (IRF) is seeking a motivated individual to join the Solar System Physics and Space Technology (SSPT) research program in Kiruna to investigate a recently discovered plasma component of airless celestial bodies: negative ions. SSPT has developed and built the first ever negative ion detector for use beyond Earth's orbit, NILS (Negative Ions on the Lunar Surface), which recently discovered this component on the lunar surface. The PhD student will perform further calibrations of the NILS backup instrument using the IRF's own facilities. The calibration data will be used to improve and extend the NILS instrument response, which in turn will form the basis for a reanalysis of the NILS data collected from the Moon. The new results and experiences from the calibration work, as well as the development of new analytical methods, will also be used in the work on the next generation of ultrasensitive detectors for negative ions in space. The position is part of the MSCA (Marie Skłodowska-Curie Actions) PhD network "Physics and Applications of Negative IONS (PANIONS)" funded by HORIZON-MSCA-DN-2024. Information on research at the IRF is available at: https://www.irf.se Qualifications To be eligible for MSCA funding, the applicant must not have been resident in Sweden for more than 12 months in the last three years before the reference date ("mobility requirement"). In addition, the applicant must be at the beginning of his/her research career (maximum four years of full-time research experience) and not have obtained a PhD degree. The PhD student will be admitted to the Department of Physics at Umeå University and must therefore meet the university's requirements. Information on the PhD program can be found at: https://www.umu.se/institutionen-for-fysik/ Terms The appointment is for four years. In accordance with MSCA rules, the PhD student will work exclusively within the PANIONS network with funding from MSCA for the first 36 months. The last 12 months are funded through internal projects at the IRF. The position is located at the IRF headquarters in Kiruna and requires physical presence to carry out the work. The application should include: