In this work, a new scintillation detector called $\textbf{MD-ICN}$ was implemented in Mexico City over a two-year period, from 2023 to 2025. The detector, installed at the Nuclear Sciences Institute (UNAM), measures the muonic component of secondary cosmic radiation using a DAQ system based on fast and nuclear modular electronics, capable of identifying significant fluctuations caused by plasma material originating from the Sun. A correction for atmospheric pressure effect was performed using a dataset covering the period from September 2023 to September 2025, yielding an average value of (-0.215 $\pm$ 0.007) % mb$^{-1}$. During 2024, the diurnal variation was calculated, showing a maximum amplitude of 0.25% at 11 a.m. local time. The muon flux was determined from the measured counting rate and the detector geometry, leading to an average value of 97.7 $\pm$ 2.5 (stat ⊕ syst) m$^{-2}$ s$^{-1}$ sr$^{-1}$, in agreement with a previous measurement at the same location. Furthermore, the detector was compared with the Neutron Monitor at the UNAM Cosmic Ray Observatory, resulting in a correlation of r = 0.91, indicating that muon flux variations are less pronounced than neutron flux variations for the same relative changes. For the purpose of designing future practical and low-cost detectors, a BMP280 pressure/temperature sensor was integrated, and digital counters based on Arduino and FPGA technologies were developed, with the aim of implementing them in smaller detectors. GEANT4 simulations are currently underway to model the detector within the building environment and study the impact of surrounding structures on its response.

diego.martinez@correo.nucleares.unam.mx

Diego Martinez-Montiel