The observation of Ground Level Enhancement GLE 77 by the neutron detectors of the Experimental Complex NEVOD
Evgenii Volkov, Kseniia Chelidze, Dmitrii Gromushkin, Semen Khokhlov, Evgenii Khomchuk, Anatoly Petrukhin, Ivan Shulzhenko
TL;DR
This paper reports the first observation of a Ground Level Enhancement (GLE) by neutron detectors designed for extensive air shower studies at the Experimental Complex NEVOD, triggered by a solar X-class flare. The study leverages a 2024 modernization that added dedicated channels for neutron-flux variation measurements across the PRISMA-36 and URAN arrays, totaling 108 detectors with an effective area of $39 \text{ m}^2$. The GLE77 event shows near-simultaneous onset around 10:15 UT with peak increases of $20.1\% \pm 1.1\%$ (PRISMA-36) and $24.8\% \pm 1.3\%$ (URAN), aligning with measurements from the MOSC NM and exhibiting a Classic (Narrow) profile; these results validate EC NEVOD neutron detectors as viable tools for monitoring solar-driven neutron flux variations. The findings indicate the potential for integrating EC NEVOD detectors into the Global Neutron Monitor Network, enhancing SEP studies and cross-validation across networks.
Abstract
A Ground Level Enhancement event was observed by neutron detectors designed for the registration of extensive air showers at the Experimental Complex NEVOD. The potential for that was unlocked by a recent modernization of the experimental setup that included implementation of additional channels for measuring neutron flux variation. At 10:15 UT on November 11, 2025, a sudden and significant increase in the neutron flux was detected by two installations: PRISMA-36 and URAN arrays. For the first time, a GLE has been recorded using a set of neutron detectors oriented at the extensive air shower studies. We present the measured EC NEVOD data and the results of the preliminary analysis of the observed GLE.