¶ Research Center of Cosmic Rays and Radiation Events in the Atmosphere (CRREAT)
CRREAT is in its sustainability phase (2024–2029); the implementation period of the project was closed in June 2023. The centre continues to operate and further develop all research infrastructures built within the project, to publish, to train students and to acquire new national and international projects.
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The CRREAT team performs measurements of atmospheric radiation and ionisation events on satellites, aircraft, stratospheric balloons, unmanned aerial vehicles, mobile (storm-chasing) laboratories and ground stations. The results contribute to the improvement of space weather models, to air transport safety, to space dosimetry and to the reliability of global navigation systems.
CRREAT was founded in Czechia in 2016 and has played a key role in developing the infrastructure needed for high-energy atmospheric measurements.
The Nuclear Physics Institute of the CAS (NPI), the Institute of Atmospheric Physics of the CAS (IAP) and the Faculty of Electrical Engineering of the Czech Technical University in Prague (FEE CTU) joined their human and instrumental resources to address open questions in the detection and dosimetry of ionising radiation of both cosmic and terrestrial origin. Cosmic rays are a key phenomenon for the investigation of the origin and composition of the universe; ionising radiation in the atmosphere also represents a health risk for aircraft crews and passengers.
The project was supported by the European Structural and Investment Funds through the Ministry of Education, Youth and Sports (MEYS), Operational Programme Research, Development and Education (project Reg. No. CZ.02.1.01/0.0/0.0/15_003/0000481, total budget 148.4 M CZK), in combination with institutional support of NPI, IAP and CTU. Activities in the sustainability phase are financed from follow-up national and international projects, contract research and institutional funding.
¶ Current highlights (2025–2026)
- First reported detection of a winter continental gamma-ray glow in Europe, observed at the Milešovka Observatory and published in Atmospheric Chemistry and Physics (Šlegl et al., 2025).
- LAMA (Large Area MOSAIC Array) – a directional detector of 36 units for secondary muons and RREA-related phenomena – is in operation on the NPI measuring container at Milešovka, alongside SEVAN, the Mini Neutron Monitor and GEODOS. Milešovka is part of the international SEVAN and GASTRON networks.
- CZPAD – a personal active dosimeter for the Czech astronaut mission, based on SPACEDOS. The engineering model was successfully tested on 5 May 2026 during a hydrogen-balloon flight to almost 33 km, which measured the altitude profile of cosmic radiation including the Regener–Pfotzer maximum at about 17 km.
- SPACEDOS data in the NASA open database RadLab, following the Fulbright–Masaryk research stay of Martin Kákona at LBNL/NASA.
- STRATELEC – instrumentation prepared with CNES and the LPC2E laboratory for a stratospheric balloon that should measure above thunderclouds from November 2026, for the first time simultaneously recording gamma radiation and the electromagnetic signatures of lightning development.
- MERIT fellowship of Dr. Aleksandr Kostinskij at NPI: wind turbines as efficient generators of electrical discharges, X-rays, relativistic electrons and upward lightning, with a link to LOFAR.
- Czechia joined ERIC LOFAR in 2025; the Czech LOFAR station is expected in 2028–2029, with NPI as an important scientific partner.
- CRREAT hosts the 29th WRMISS Workshop (Radiation Monitoring to assess human exposures Inside the Solar System), Prague, 1–3 September 2026.
¶ Key Activities
(i) building an excellent team of researchers that contributes to clarifying the unexplained radiation phenomena in the atmosphere,
(ii) modernisation of the research infrastructure,
(iii) increasing the scientific performance of the collaborating subjects,
and (iv) enhancing international cooperation.
¶ Objectives
To deepen the knowledge about the relation between atmospheric phenomena and ionising radiation (IR).
To clarify phenomena causing variations of the secondary cosmic particles (SCP) in the atmosphere.
The objectives are complementary. Thus a partial accomplishment of one of the objectives should contribute to the accomplishment of the other.
Objective 1 is achieved by proving a previously not clearly demonstrated connection between an atmospheric phenomenon and ionising radiation – for example the detection of ionising radiation generated by an atmospheric discharge, or lightning generation triggered by a secondary cosmic particle shower.
Objective 2 is achieved by proving the effect of a newly identified atmospheric parameter on the detection of SCP, or by significantly improving the understanding of an effect of a previously identified parameter.
The acquired knowledge helps to improve the precision of aircraft crew dosimetry and space dosimetry, cosmic weather modelling and modelling of electromagnetic signal propagation, may enable prediction of lightning occurrence, and brings understanding to yet unexplained atmospheric phenomena.
¶ Main Outcomes
- the relationship between storm activity and cosmic radiation,
- changes in aircraft radiation doses connected with short-term variations in the atmosphere, mainly lightning,
- description and understanding of the lightning initiation process by monitoring the vertical hydrometeor profile and electric field modelling.
Outcomes are potentially applicable in other fields: thunderstorms and lightning in particular pose a danger not only to aviation but also to the general population, electricity distribution, fire safety, etc.
¶ International cooperation
At the start of the project in 2016, eight research institutions from Armenia, France, Japan, Germany, Russia, Slovakia and the USA expressed their professional support for CRREAT, which anticipated a wide scientific collaboration.
CRREAT cooperates with partners in Europe, Asia and the USA, in particular with ESA (CZPAD, ZOE, ESADOS), NASA/LBNL (RadLab), QST/NIRS Japan (HIMAC), the Institute of Experimental Physics SAS and the Lomnický štít high-mountain observatory, the Korea Institute of Nuclear Safety (MoU 2026–2030), CNES and LPC2E (France), ASTRON/LOFAR, the Aragats Space-Environmental Center (Armenia), the SEVAN and GASTRON networks and European metrology partners (EURAMET, Euratom/PIANOFORTE).
