ISMIS - Radioactivity Measurements

ISMIS (Infrastructure Group for Ionizing Radiation Measurements - Radioactivity Measurements) is a group of laboratories within the Department F2. The basic program of work in ISMIS represents the research in atomic and nuclear physics, research in biological and geochemical cycles, radiochemistry and radioecology, and environmental protection. The contents of chemical elements and radioactive isotopes in the samples are determined using dedicated measurement analytical methods. The analytical methods are accredited according to the ISO / IEC 17025: 2017 standard. Laboratories in the group are:

The vision of ISMIS is that through excellent research we constantly contribute fundamental discoveries to the domestic and global treasury of knowledge, take part in applied interdisciplinary research areas related to current societal challenges such as environmental protection, safe food, drinking water, health and climate changes. We constantly transfer knowledge to younger generations and thus contribute to the sustainable development of new knowledge. ISMIS offers support to research and professional entities and organizations in the Republic of Slovenia and in industry, which need a fast, high-quality, reliable and comprehensive analytical solution to the challenge, which should otherwise be (partially) sought elsewhere.

In addition to basic science activities, the Group is active in conducting the environmental radioactivity monitoring in the Republic of Slovenia, off-site radiological monitoring of the Krško Nuclear Power Plant (NEK), off-site monitoring of radioactivity of the Central Radwaste Storage Facility at Brinje (ARAO), independent control of operational radioactivity monitoring in the vicinity of Krško NPP, monitoring of radioactivity in feedstuff and foodstuff. In addition to environmental monitoring, we measure personal and environmental (ambient) doses of ionizing radiation with thermoluminescent dosimeters. Within the framework of accreditation, we successfully participate in international intercomparisons and demonstrate outstanding qualification in these activities. The Laboratory for Dosimetry Standards regularly performs calibrations at testing of all kinds of radiation protection instruments (personal dosemeters, survey dosemeters), thus ensuring metrological traceability to end-users of these devices in Republic of Slovenia and in the region.

Members of the Infrastructure Group for Ionizing Radiation Measurements are making a significant contribution to the improvement of environmental safety and emergency preparedness (EPR) in Slovenia and worldwide in the framework of the Ecological Laboratory with a mobile unit (ELME). With the ELME we provide regular on-call time duties and we are regularly trained and educated taking part in regular field drills and exercises.


In 2008 Jožef Stefan Institute was appointed by Metrology Institute of the Republic of Slovenia (MIRS) as Designated Institute (DI) and as the holder of national standard (NNE) in the field of ionizing radiation for:

  • air kerma , K, (J/kg) special name gray (Gy)
  • dose equivalent, H, (J/kg) special name sievert (Sv)
  • activity, (s⁻¹) special name becquerel (Bq)

The Laboratories for Dosimetry Standards (NDS) and Radioactivity Measurements (LMR) prove their measuring capabilities with exceptional and comparable results in intercomparisons at the highest international level, in which other world-renowned metrological institutions also participate. In 2015, on the basis of intercomparison results at the highest level obtained for Hp(10) in the x-ray radiation qualities of the N-series, ¹³⁷Cs, ⁶⁰Co  and ²⁴¹Am, for kerma in the x-ray radiation qualities of the N-series, and in the x-ray radiation field of RQR and RQA qualities, the best Calibration and Measurement Capabilities (CMC) of the Laboratory for dosimetry standards were approved and reported by BIPM. Alike the CMCs for the Laboratory for dosimetry standards, the CMCs for the Laboratory for radioactivity measurements (LMR) were approved in 2015. The CMCs relate to the best results obtained for specific activities of  ²¹⁰Pb , ²²⁶Ra and ²³⁸U in phosphorgypsum and for specific activities of ⁴⁰K in ¹³⁷Cs in wild bilberry powder. Detailed data are available on the BIPM KCDB website.