Development of a cost-effective plastic scintillator for cosmic-ray muon radiography of a volcano

摘要

Muon radiography has recently made it possible to perform imaging of the internal structure of a volcano. Muon-detecting experiments were carried out at Asama and Usu volcanoes using a newly developed scintillator. The goal was to build a large detector that would improve the quality of the data collected by the muon radiography experimental set-up that is currently being used to study volcanic activities. To this end, a costeffective plastic scintillator was developed by a simple "heating-melting method". The detector consists of planes of scintillator strips and is currently in the prototyping phase. Using a cosmic-ray muon source, we found that the signal from our scintillator was consistent with the zenith-angle dependence of the cosmic-ray muon spectrum with no significant attenuation effects in the scintillator. We confirmed that our scintillators can be incorporated into a portable assembly-type cosmic-ray muon telescope system.