Utilization-focused evaluation of relationship among spatial, temporal, and density resolutions of muography

Abstract Muography is a method that estimates the density distribution inside an object based on observations of the number of muons transmitted through the object. In recent years, detectors have been downsized for subsurface applications, which has led to diversification of exploration targets. The practical application of muography to diverse targets requires a utilization-focused evaluation of the spatial, temporal, and density resolutions to optimize performance. A previous study developed an evaluation formula that utilizes the relationship among minimum observation time required for anomaly detection, density anomaly contrast, and detector angular resolution . However, the influence of the anomaly size on spatial resolution has not been considered. In addition, although it is widely believed that downsizing the detector can increase spatial resolution, the physical downsizing limit has not been determined. With a utilization focus, we propose a stochastic method for evaluating the relationship among the spatial, temporal, and density resolutions of muography. We conduct a muon simulation and apply our method to the muon simulation data. We investigate the applicability of the existing evaluation formula by comparing with these results. Finally, we demonstrate that the achievable resolution significantly depends on anomaly size, which is closely related to human visual cognition. In addition, we infer the downsizing limit of the detector.