The Tracking Ultraviolet Set-up (TUS) is the world’s first orbital imaging detector of Ultra High Energy Cosmic Rays (UHECR) and it operated in 2016–2017 as part of the scientific equipment of the Lomonosov satellite. The TUS was developed and manufactured as a prototype of the larger project K-EUSO with the main purpose of testing the efficiency of the method for measuring the ultraviolet signal of extensive air shower (EAS) in the Earth’s night atmosphere. Despite the low spatial resolution (∼5 × 5 km² at sea level), several events were recorded which are very similar to EAS as for the signal profile and kinematics. Reconstruction of the parameters of such events is complicated by a short track length, an asymmetry of the image, and an uncertainty in the sensitivity distribution of the TUS channels. An advanced method was developed for the determination of event kinematic parameters including its arrival direction. In the present article, this method is applied for the analysis of 6 EAS-like events recorded by the TUS detector. All events have an out of space arrival direction with zenith angles less than 40°. Remarkably they were found to be over the land rather close to United States airports, which indicates a possible anthropogenic nature of the phenomenon. Detailed analysis revealed a correlation of the reconstructed tracks with direction to airport runways and Very High Frequency (VHF) omnidirectional range stations. The method developed here for reliable reconstruction of kinematic parameters of the track-like events, registered in low spatial resolution, will be useful in future space missions, such as K-EUSO.

This work reports the synthesis and characterization of Carbon Quantum Dots (CQDs) embedded in an organic–inorganic hybrid SiO₂: PMMA matrix, designed as a novel plastic scintillator material. The CQDs were synthesized through a solvo-hydrothermal method and incorporated using a sol–gel polymerization process, resulting in a mechanically durable and optically active hybrid. Structural analysis with X-ray diffraction and TEM confirmed crystalline quantum dots approximately 10 nm in size. Extensive optical characterization, including band gap measurement, photoluminescence under 325 nm UV excitation, lifetime evaluations, and quantum yield measurement, revealed a blue emission centered at 426 nm with a decay time of 3–3.6 ns. The hybrid scintillator was integrated into a compact cosmic ray detector using a photomultiplier tube optimized for 420 nm detection. The system effectively detected secondary atmospheric muons produced by low-energy cosmic rays, validated through the vertical equivalent muon (VEM) technique. These findings highlight the potential of CQD-based hybrid materials for advanced optical sensing and scintillation applications in complex environments, supporting the development of compact and sensitive detection systems.

Luminescent gadolinium oxide nanoparticles doped with europium were synthesized through a precipitation reaction using gadolinium and europium nitrates as precursors. The europium-doped gadolinium oxide nanoparticles were incorporated first into a gel matrix of silicon dioxide and second by mixing with polymethyl methacrylate. Both processes are synthesized by the simultaneous hydrolysis of tetraethyl orthosilicate and polymerization of 3-(Trimethoxysilyl) propyl methacrylate. The solid samples obtained are round in shape with a size of about 2.5 cm, which makes the material easy to handle to test different applications. The inclusion of Gd₂O₃:Eu³⁺ nanoparticles increases the level of absorbance in the ultraviolet region, which allows for the improved emission of the material at a wavelength of around 610 nm. Furthermore, it enables easy doping of the material and the fabrication of thin films and monoliths with potential optical applications.

Luminescent gadolinium oxide nanoparticles doped with europium were synthesized through a precipitation reaction using gadolinium and europium nitrates as precursors. The europium- doped gadolinium oxide nanoparticles were incorporated first: into a Gel matrix of silicon dioxide; and second: mixing with Polymethyl Methacrylate. Both processes are synthesized by the simultaneous hydrolysis of tetraethyl orthosilicate and polymerization of 3-(Trimethoxysilyl) propyl methacrylate. The solid samples obtained are round in shape with a size of about 2.5 cm, which makes it easy to handle to test different applications. The inclusion of Gd2O3:Eu3+ nanoparticles increases the level of absorbance in the ultraviolet region, which allows for improved emission of the material at a wavelength of around 609 nm. Furthermore, it enables easy doping of the material and the fabrication of thin films and monoliths with potential optical applications.