Research articles, complete author lists, abstracts and available manuscripts. Open a publication for its permanent page, DOI and downloadable citations.
Publications (11)
Viviane Pierrard, Solar-Terrestrial Center of Excellence, Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium, David Bolsée, Alexandre Winant, Amer Al-Qaaod, Faton Krasniqi, Maximilien Péters de Bonhome, Edith Botek, Lionel Van Laeken, Danislav Sapundjiev, Roeland Van Malderen, Alexander Mangold, Iva Ambrozova, Marek Sommer, Jakub Slegl, Styliani A Geronikolou, Alexandros G Georgakilas, Alexander Dorn, Benjamin Rapp, Jaroslav Solc, Lukas Marek, Cristina Oancea, Lionel Doppler, Ronald Langer, Sarah Walsh, Marco Sabia, Marco Vuolo, Alex Papayannis, Carlos Granja, Earth and Life Institute—Climate Sciences (ELI-C), Université Catholique de Louvain, Louvain-la-Neuve, Belgium, Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, Braunschweig, Germany, Centre for Mathematical Plasma Astrophysics, Katholiek Universiteit Leuven, Leuven, Belgium, Royal Meteorological Institute of Belgium (IRM-KMI), Brussels, Belgium, Nuclear Physics Institute of the Czech Academy of Sciences, Rez, Czech Republic, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague, Czech Republic, University Research Institute of Maternal & child Health & Precision Medicine, National & Kapodistrian University of Athens, Medical School, Athens, Greece, Biomedical Research Foundation of the Academy of Athens, Athens, Greece, DNA Damage Laboratory, Department of Physics School of Applied Mathematical and Physical Sciences, National Technical University of Athens (NTUA), Athens, Greece, MPG MPIK: Max Planck Institute for Nuclear Physics, Heidelberg, Germany, Université Paris-Saclay, CEA, List, Laboratoire National Henri Becquerel (LNE-LNHB), F-91129, Palaiseau, France, Czech Metrology Institute (CMI), Brno, Czech Republic, ADVACAM, Prague, Czech Republic, DWD, MOL-RAO Deutscher Wetterdienst, Meteorologisches Observatorium Lindenberg—Richard-Aßmann-Observatorium, Lindenberg (Tauche), Germany, Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic, Eutelsat, One Web, London, United Kingdom, European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Noordwijk, The Netherlands, Laser Remote Sensing Unit, Department of Physics, National & Technical University of Athens, Zografou, Greece, Laboratory of Atmospheric Processes and their Impacts, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, VSB Technical University of Ostrava, Ostrava, Czech Republic
In this work, we analyzed simultaneous observations of solar particles and solar electromagnetic ultraviolet (UV) radiation during solar events from January 2024 to May 2024. Measurement campaigns to study the effects of space radiation on the terrestrial atmosphere were conducted in the framework of the project BIOSPHERE. We show the results of the campaign in Brussels from 1 January 2024 to 31 March 2024, during which several solar energetic particle (SEP) events were observed by the spacecraft GOES and OMNI, together with two big geomagnetic storms in March 2024 and May 2024 associated with solar eruptions. The last two events combine the arrival of a SEP event with a geomagnetic storm. On 11 May 2024, the biggest geomagnetic storm for the last 20 years was observed. These events enabled us to identify effects due to UV, solar particles, and geomagnetic storms. The impact of these events on the terrestrial radiation belts, illustrated by satellite observations like PROBA‑V/EPT and on the atmospheric ozone using AURA/MLS is demonstrated. For the measurement campaign, muon and neutron monitors showed a Forbush decrease only during the geomagnetic storm at the end of March 2024 and in May 2024. Complemented by a simulation of radiation effects on the ionization rate of the atmosphere as a function of the altitude, the extensive range of different observations available during this measurement campaign demonstrated that SEP and geomagnetic storms due to solar eruptions had very different effects on the terrestrial atmosphere. The geomagnetic storms mainly modified the energetic electrons trapped in the space environment of the Earth and affected the ionization of the atmosphere above 60 km. They also modified the cosmic ray injections, mainly at high latitudes, creating Forbush decrease for the most intense ones. SEP events injected energetic protons in the atmosphere that could penetrate deeper in the atmosphere because they had more energy than the electrons. They could impact ozone, mainly at high altitude in the thermosphere. Solar activity variation associated with the rotation of the solar active regions in 27 days modulated UV
L. Marek, C. Granja, J. Jakubek, J. Ingerle, D. Turecek, M. Vuolo, C. Oancea
Hybrid semiconductor pixelated detectors from the Timepix family are advanced detectors for online particle tracking, offering energy measurement and precise time stamping capabilities for particles of various types and energies. This inherent capability makes them highly suitable for various applications, including imaging, medical fields such as radiotherapy and particle therapy, space-based applications aboard satellites and the International Space Station, and industrial applications. The data generated by these detectors is complex, necessitating the development and deployment of various analytical techniques to extract essential information. For this purpose, and to aid the Timepix user community, the "Data Processing Engine" (DPE) was developed as an advanced tool for data processing designed explicitly for Timepix detectors. The DPE includes three processing levels: pre-processing (clusterization, calibrations, corrections), processing (particle classification using machine learning, radiation field recognition), and post-processing (directional and coincidence analysis, physics products generation). It is supported by a database of typical radiation field references and is accessible via command-line, API, and web interface.
Carlos Granja, Corinne Barber, Sandra Barna, Jeffery Chancellor, David Chvatil, Loic Grevillot, David Inzalaco, Jan Jakubek, Zdenek Kohout, Giulio Magrin, Lukas Marek, Radu Mihai, Cristina Oancea, Vaclav Olsansky, Trevor Olsen, Dusan Poklop, Stanislav Pospisil, Andreas Resch, Andrea Sagatova, Michael Sivertz, Jan Stursa, Rudolf Sykora, Ivan Wilhelm, Vaclav Zach, Bohumir Zatko
Silicon Carbide is a suitable semiconductor sensor for radiation measurement and nuclear applications. It has been recently implemented as a position-sensitive and radiation imaging device coupled to the Timepix3 ASIC chip in the form of a miniaturized radiation camera MiniPIX-Timepix3 SiC. In this work we systematically evaluate the detection resolving power to different radiation species: electrons, fast neutrons, ions and protons. Experimental calibrations were made at well-defined reference fields in terms of particle type, energy and direction. The spectral-sensitive tracking response and characteristic morphology of the particle tracks are analyzed by pattern recognition algorithms. The low thickness of the radiation sensitive volume (65 μm) of the SiC sensor limits the directional tracking response and angular resolution. Three broad classes of particle-type events are resolved. The detector together with suitable data processing can be used for radiation dosimetry and particle tracking tasks in space, particle therapy, nuclear physics and nuclear reactors and particle accelerator environments.
C. Granja, R. Uhlar, D. Poklop, P. Alexa, V. Zach, C. Oancea, L. Marek
Monitoring and characterization of particle beams in wide-range is often necessary in research and many applications with particle accelerators. The quantitative measurement and evaluation of composition especially of high-intensity beams are limited and can become a challenge with conventional methods especially with simplified instrumentation for ease of deployment. For this purpose, we developed a novel technique based on high-resolution spectral-sensitive tracking of single particles scattered from the beam path by a thin foil. We use a compact radiation camera equipped with the semiconductor pixel detector Timepix3 together with dedicated Monte-Carlo simulations. Particle-event type discrimination and directional information are produced by the detector spectral-tracking response together with particle-type resolving power derived from experimental calibrations. Directional- and spectral-sensitive components can be resolved in wide field-of-view. Quantification of the primary beam intensity is extrapolated by numerical calculations. Demonstration and evaluation of the technique are provided by measurements with 33 MeV protons from a light ion cyclotron accelerator. Scattered particles originating from the thin foil, the accelerator beam nozzle, and the air space along the beam path are detected and evaluated.
C. Granja, J. Solc, J. Gajewski, A. Rucinski, P. Stasica, M. Rydygier, L. Marek, C. Oancea
Mixed radiation fields in environments such as particle radiotherapy and outer space exhibit large complexity in terms of composition and spectral distribution which are difficult to measure in detail. For this purpose, we present a high-sensitivity technique using the pixel detector Timepix3 to measure the composition and spectral-tracking characterization of secondary fields produced in proton radiotherapy. Particle-event classes are resolved into broad groups of high-energy transfer particles (HETP), such as protons, ions and neutrons, as well as low-energy transfer particles (LETP), such as electrons, X rays and, partly, low-energy gamma rays. The quantum-imaging capability of Timepix3 is exploited to enhance the resolving power for particle-type classification. The particle tracks are analyzed by spectral-sensitive pattern recognition algorithms. The response matrix for Timepix3 is newly derived based on experimental calibrations in well‑defined radiation fields including in‑beam rotational scans of protons performed at various energies and directions. Clinical proton beams of radiotherapeutic intensities and energies in the range 12–225 MeV were used in experimental configurations with and without a tissue‑equivalent phantom. Detailed results of radiation components can be used to produce total and partial particle fluxes, dose rate, absorbed dose, deposited energy and linear‑energy‑transfer (LET) spectra. Dedicated Monte Carlo (MC) simulations are compared with experimental results of field composition, particle fluence, and deposited energy. The numerical information aids the interpretation of experimental data which includes also secondary neutrons. The technique and developed methodology can be applied for research and routine measurements in environments of varying complexity.
Carlos Granja, Herve Chanal, Vaclav Zach, David Chvatil, Cristina Oancea, Dusan Poklop, Vaclav Olsansky, Jan Jakubek
We performed detailed measurements of the secondary cosmic ray field in the lower atmosphere using a miniaturized particle telescope composed of two closely stacked Timepix3 detectors in synchronized operation. This configuration allows position-, spectral-, and time-sensitive particle tracking, enabling high angular resolution and enhanced particle-type discrimination. Validation was performed with proton and electron beams. Ground-based cosmic ray measurements at 200 m altitude (Prague) yielded detailed composition and directional distributions of the charged particle component, notably muons. The angular flux of muons was measured across a wide field-of-view with enhanced discrimination from photon and electron components. Experimental results are compared with model estimates, demonstrating the telescope's capability for precise cosmic radiation mapping with compact instrumentation.
A. Novak, C. Granja, A. Sagatova, V. Zach, J. Stursa, C. Oancea
This work evaluates the performance of the Timepix3 detector equipped with different semiconductor sensors (GaAs:Cr, CdTe, and Si) for spectral tracking of proton beams. Measurements were performed at the U120-M cyclotron using monoenergetic proton beams (8–31 MeV) and varying incident angles. Detectors were calibrated and operated in data-driven mode with the AdvaPIX interface. Results include deposited energy, track morphology, and LET spectra, with clear dependence on sensor material, thickness, and bias voltage. High-Z materials (CdTe, GaAs:Cr) showed superior energy deposition and stopping power compared to Si. Cluster analysis revealed performance differences in resolution and particle discrimination across sensors. The study supports optimizing sensor choice for high-LET particle detection in applications like ion therapy and space radiation. Future work includes Monte Carlo validation and testing novel materials like SiC and refined GaAs.
David Alvarez Castillo, O. Sushchov, M. Bielewicz, T. Wibig, C. Oancea, C. Granja, N. Zabari
This article reviews recent advancements by the Cosmic Ray Extremely Distributed Observatory (CREDO), a global initiative leveraging both scientific infrastructure and citizen science to study cosmic ray ensembles (CRE). CREs are correlated cosmic rays potentially originating from exotic physical processes, such as photon splitting in magnetospheres or ultra-high-energy photon interactions near the Sun. The work highlights CRE detection through both ground-based detectors and mobile devices like smartphones. Simulations using CRPropa3 and PRESHOWER help model CRE formation and propagation. The study explores fundamental physics topics including Lorentz invariance violation and variation of fundamental constants. Machine learning aids in identifying particle events from smartphone data. One major goal is detecting cosmic ray fluctuations as potential earthquake precursors. The CREDO-Mexico and CREDO-Maze projects aim to establish detection networks in schools and seismically active regions. The collaboration also works with private companies like ADVACAM and Astroteq, utilizing cutting-edge detectors and AI forecasting systems.
St. Gohl, M. Malich, B. Bergmann, P. Burian, C. Granja, E. Heijne, M. Holik, J. Jacubek, J. Janecek, L. Marek, C. Oancea, M. Petro, S. Pospisil, A. Smetana, P. Soukup, D. Turecek, M. Vuolo
A Miniaturized Radiation Monitor (MIRAM) has been developed for the continuous measurement of the radiation field composition and ionizing dose rates in near earth orbits. Compared to currently used radiation monitors, the presented device has an order of magnitude lower weight while being comparable in power consumption and functionality. MIRAM is capable of on‑board real‑time self‑diagnostic. Furthermore, it supports on‑board analysis of the measured data to be able to work autonomously. The dose rate is calculated continuously based on the energy deposition in the Timepix3 detector. For the estimation of the particle species composition of the radiation environment, two methods are applied depending on the current flux. At lower fluxes (<10⁴ particles cm⁻² s⁻¹), a track‑by‑track analysis based on temporal coincidence is applied. At higher fluxes, a less power and memory consuming method is utilized. This method is using the averaged deposited energy per pixel to estimate the electron and proton content of the radiation field.
C. Granja, J. Jakubek, P. Soukup, M. Jakubek, D. Turecek, L. Marek, C. Oancea, S. Gohl, B. Bergmann, S. Pospisil, M. Malich, M. Vuolo, A. Owens, V. Zach, J. Stursa, D. Chvatil, V. Olsansky, A. Rucinski, J. Gajewski, P. Stasica, Z. Vykydal, J. Solc
The miniaturized radiation camera MiniPIX TPX3 is designed for detailed and wide-range measurements of mixed-radiation fields present in many applications such as radiotherapy and space radiation. The highly integrated instrumentation utilizes a single connector for control and readout for flexible measurements and quick deployment. The device features an option to process the registered data on the same device with limited resolution and basic particle-type resolving power. A novel readout and data processing technique exploits the detector's high granularity and dual per-pixel signal electronics to measure and characterize high-intensity radiation fields with basic particle-type discrimination.
Piotr Homola, Dmitriy Beznosko, Gopal Bhatta, Łukasz Bibrzycki, Michalina Borczyńska, Łukasz Bratek, Nikolay Budnev, Dariusz Burakowski, David E. Alvarez-Castillo, Kevin Almeida Cheminant, Aleksander Ćwikła, Punsiri Dam-o, Niraj Dhital, Alan R. Duffy, Piotr Głownia, Krzysztof Gorzkiewicz, Dariusz Góra, Alok C. Gupta, Zuzana Hlávková, Martin Homola, Joanna Jałocha, Robert Kamiński, Michał Karbowiak, Marcin Kasztelan, Renata Kierepko, Marek Knap, Péter Kovács, Szymon Kuliński, Bartosz Łozowski, Marek Magryś, Mikhail V. Medvedev, Justyna Mędrala, Jerzy W. Mietelski, Justyna Miszczyk, Alona Mozgova, Antonio Napolitano, Vahab Nazari, Y. Jack Ng, Michał Niedźwiecki, Cristina Oancea, Bogusław Ogan, Gabriela Opiła, Krzysztof Oziomek, Maciej Pawlik, Marcin Piekarczyk, Bożena Poncyljusz, Jerzy Pryga, Matías Rosas, Krzysztof Rzecki, Jilberto Zamora-Saa, Katarzyna Smelcerz, Karel Smolek, Weronika Stanek, Jarosław Stasielak, Sławomir Stuglik, Jolanta Sulma, Oleksandr Sushchov, Manana Svanidze, Kyle M. Tam, Arman Tursunov, José M. Vaquero, Tadeusz Wibig, Krzysztof W. Woźniak
The Cosmic-Ray Extremely Distributed Observatory (CREDO) is a global collaboration designed to study cosmic rays and their interactions through an extremely distributed network of detectors. By using existing infrastructure such as smartphones, educational setups, and scientific detectors, CREDO seeks to detect cosmic-ray ensembles—correlated cosmic-ray events over large areas—potentially originating from exotic physics phenomena. The project emphasizes open access, public engagement, and citizen science, enabling contributions from scientists and non-scientists alike. This approach allows for new scientific insights while simultaneously providing educational and outreach opportunities. The paper discusses the scientific goals, current status, and future plans for CREDO, demonstrating its potential for both scientific advancement and societal impact.