Study of solar activity by using PRISMA-TU-4

Currently, solar activities are in the peak year of Cycle 25 (2024-2025), with frequent coronal mass ejections (CMEs) and high-energy particle stream events. Our research using PRISMA-TU-4 focuses on the impact of such activities on cosmic rays, such as Forbush decrease (FD) and Ground-Level Enhancement (GLE). PRISMA-TU-4 is an observation system composed of four Electron-Neutron detectors (EN-detectors), used to study the correlation between solar activity cycle and cosmic ray modulation effect. Each detector is based on $^6$Li isotope target material ($^6$Li + n $\rightarrow$ $^3$H + $\alpha$ + 4.8 MeV), capturing thermal neutrons and radioactive isotopes while recording flux changes. Installed at Xizang University (altitude 3650m), the system leverages the geographical advantage of thin atmosphere in plateau areas, significantly reducing absorption loss of cosmic ray secondary particles and improving detection sensitivity to weak thermal neutron signals. This report introduces PRISMA-TU-4 data analysis methods. Through data analysis, we eliminated impacts of local meteorological conditions and enabled high-confidence signal identification and presenting analysis results of FD.