Monte Carlo simulation for background noise study of the Wudalianchi volcanic density imaging

Abstract

In our muon radiography experiment on the Wudalianchi volcano in northeastern China, the muon flux was overestimated and the volcano density was underestimated due to the contamination by background noise. In our past simulation work on background noise, we did not construct the volcano model, we just simply used the volcanic high-resolution topographic map data and the cosmic ray particle source data to obtain the penetrating muon energy spectrum. In order to study the background noise and volcanic density more accurately and in detail, we used the GEANT4 tool to construct a virtual volcano and a virtual detector, and combined the cosmic ray shower library (CRY) to simulate the interaction between the volcano and cosmic ray particles. The results show that the background noise in volcano muon radiography is mainly composed of particles with low-energy (less than 1GeV). According to the elimination device to reduce the background particles, the volcano density map we obtained is closer to the simulated value than the map before eliminating. This research has implications for our next volcano experiments.