For the data on the observation times and directions of the motion of extensive air showers, which are observed at two stations of the GELATICA network, for the first time we apply the method we have developed previously for identifying pairs of mutually remote extensive air showers, the ancestor particles of which arose, possibly, in a single process. A brief description of the GELATICA network, a review of the properties of used samples of data on shower observations at two stations of the network during the 2019–2021 session, and the result of applying the above method to them are given. Some properties of a single peculiar pair of remote showers are discussed. A side question arose about the cause of the observed temporal asymmetry in the locations of the regions of mutual approach of independent primary cosmic ray particles.

Cosmic rays interact with fields and background radiation as they propagate in space, producing particle cascades of various sizes, shapes and constituents. The potential observation of at least parts of such phenomena, referred to as cosmic-ray ensembles (CRE), from Earth would open a new channel of cosmic-ray investigation, since it might be a manifestation of fundamental symmetries of nature. Research dedicated to CRE is one of the main scientific objectives of the Cosmic-Ray Extremely Distributed Observatory (CREDO) Collaboration, and with this article we address one of the cornerstones of the relevant scientific program: the simulation method dedicated to CRE studies. Here we focus on CRE resulting from synchrotron radiation by high energy electrons as one of the most prevalent energy loss processes. Providing the example of simulation output analysis, we demonstrate the advantages of our approach as well as discuss the possibility of generalization of current research.

Reliable cosmic-ray measurements require a thorough understanding of the detector used. It is especially important when detectors are very simple like the scintillator detectors considered in this work, which provide only information about the amplitude of the signal generated by a detected particle. Arrays of these devices can work in coincidental setups to detect Extensive Air Showers caused by high-energy primary cosmic rays. Due to their low cost and simple design, they can be used as elements of large detector networks needed for the search for global correlations in the cosmic rays. To be able to interpret data collected by those arrays, extensive simulations of such detectors are necessary to determine their efficiency of detection of different types of particles. This work presents the results of analysis of such simulations performed using the Geant4 software (v1.1.2). The analysis results lead to the conclusion that detectors feature almost maximal (close to 100%) efficiency for the detection of cosmic-ray muons and electrons with momenta greater than 0.03 GeV/c. Their sensitivity to low-energy electrons and photons is lower but not negligible and has to be properly taken into account during the interpretation of collected data.