Speaker
Description
Muon scattering tomography enables non-destructive imaging of dense or shielded structures for which absorption-based techniques fail. Since the muon scattering angle correlates with the atomic number of the traversed material, high-Z inclusions can be identified within lower-density surroundings. A common objective is therefore to image regions of enhanced scattering by statistical analysis of reconstructed muon trajectories and their angular deviations. Among the available reconstruction methods, the Point of Closest Approach (PoCA) algorithm provides a computationally efficient approximation by reducing Multiple Coulomb Scattering to a single effective interaction point. This approach is particularly suitable for scenarios involving small, dense markers embedded in a larger, lower-density structure.
In this work, the PoCA is extended to localize compact position markers of known shape in large structures. As a representative application, a lead sphere placed inside a distillation column could be considered. Its reconstructed position can serve as an indicator for internal misalignment or mechanical faults. Reliable marker localization, however, requires a quantitative understanding of measurement time, achievable spatial accuracy and additional scattering contributions from container walls and surrounding materials. The presented work addresses the development of an algorithm that evaluates the spatial distribution of reconstructed scattering points of a lead sphere within a discretized volume of interest and estimates the marker center via maximum correlation with a spherical object mask. Performance is assessed using simulated muon data generated with G4beamline, from which requirements on acquisition time and localization precision are derived. Additionally, weakly and non-scattered muons are incorporated into the workflow using a three-dimensional digital differential analyzer (3D-DDA) scheme. The developed algorithm is finally applied to experimentally acquired detector data for validation using a setup of two drift-chamber-based hodoscopes. The proposed approach provides a method for assessing muon detector performance and determining the feasibility and expected accuracy of marker localization in specific industrial applications.
Acknowledgement
This work was funded by the Helmholtz Association (Germany) with the grant number KA-TVP-37.