Speaker
Description
The Gamma Spectrometry of Thunderstorm Radiation Observatory Network (GASTRON) is a distributed system of ground-based gamma spectrometers dedicated to the detection and characterization of high-energy radiation phenomena associated with thunderstorms, including Terrestrial Gamma-ray Flashes (TGFs) and Thunderstorm Ground Enhancements (TGEs), also called gamma-ray glows. Building on previous progress and the development of a structured event catalogue, we present a comprehensive catalogue of thunderstorm radiation events measured across multiple high-altitude observatories in Europe and near sea level stations in Japan.
The network included stations in Czechia (Milešovka, Poledník), Slovakia (Lomnický štít), Germany (Zugspitze), Switzerland (Jungfraujoch), Armenia (Aragats), Bulgaria (Musala), and Japan (Kanazawa). The instrumentation comprises several types of gamma spectrometers, including GEODOS systems, RT-56 detectors, and Japanese GROWTH-type spectrometers equipped predominantly with NaI(Tl) crystals and GPS-synchronized data acquisition. The influence of detector geometry, crystal volume, energy resolution, and triggering strategies are analyzed with respect to their impact on event detection sensitivity and spectral reconstruction.
A unified event-detection algorithm, based on maximum likelihood estimation for Poisson-distributed time series, has been implemented across the network to ensure consistent identification of radiation enhancements. The algorithm determines the start and end of events, their duration, intensity, and statistical significance relative to background fluctuations. Its sensitivity can be tuned through configurable parameters and has been validated on synthetic as well as real multi-site data sets. The harmonized detection procedure enables objective intercomparison of events recorded by different detector types and at different altitudes.
The GASTRON event catalogue represents a step toward a coordinated European–Asian observational framework for thunderstorm-related radiation, providing a basis for statistical studies and atmospheric modeling validation.