An exceptionally strong gamma-ray glow at Lomnický štít observed by an unprecedented number of ionizing radiation sensors

The summer season of 2023 brought to Lomnický štít (Slovakia) one of the strongest gamma-ray glows (GrGs) ever recorded. As Lomnický štít is a unique observation point for GrGs, we equipped the observatory with multiple detectors in the frame of the CRREAT project. In addition to the existing Neutron monitor, SEVAN detector, and Boltek electric field mill, we also installed an RT-56 large NaI(Tl) gamma-ray spectrometer, a small Geodos gamma-ray spectrometer, silicon mosaic detectors, Timepix detectors, PIN diode detectors, a camera, and additional Boltek electric field mills. On 14 June 2023, a thunderstorm cell formed in the vicinity of the observatory and exhibited a strong electric field. This field caused a strong GrG detected by all of the above-mentioned ionizing radiation detectors, standing out as our finest recorded event to date, enriched by the deployment of an unprecedented set of advanced instruments. The duration of the GrG was at least five minutes and was ended by a discharge very close to the count rate's peak of a typical Gaussian curve. The thunderstorm cell remained active and produced two more detected GrGs. One of them also ended with a discharge.