Speaker
Description
Scintillator-camera detector systems are widely used in neutron radiography and tomography, yet geometric distortions and field-dependent effects are seldom characterized within a rigorous metrological framework. Uncorrected distortions can propagate into reconstructed volumes, introducing systematic dimensional bias and spatial non-uniformities that limit quantitative reliability and cross-instrument comparability.
We are developing a scalable calibration approach based on high-contrast neutron dot patterns spanning multiple spatial scales. The method relies on two-dimensional arrays of absorbing markers with precisely defined geometry, enabling dense sampling of the detector field of view. By comparing measured centroid positions with their nominal grid coordinates, distortion vector fields are derived and converted into correction maps applicable to both radiographic projections and tomographic datasets. Polynomial-based correction models are implemented using open-source tools such as Discorpy, allowing quantification of radial (barrel and pincushion) as well as non-radial and depth-related distortion components.
To support this framework, we fabricate complementary multiscale patterns adapted to different detector resolutions and fields of view. A high-resolution set, covering approximately 3 × 3 cm², is produced on silicon substrates using advanced microfabrication techniques, enabling dense arrays of micron-scale absorbing features filled with gadolinium-based contrast media to maximize neutron attenuation. For larger fields of view, aluminum plates of up to 17 × 17 cm² are machined to produce dot matrices filled with boron-based absorbing materials. Together, these targets provide scalable geometric references suitable for both compact high-resolution systems and large-area neutron imaging configurations.
By combining microfabricated and large-format targets within a unified analysis framework, this work establishes a detector-agnostic and scalable pathway toward traceable geometric calibration and improved quantitative accuracy in neutron radiography and tomography.
Key Words
Neutron imaging, Scintillator–camera detectors, Multiscale dot patterns, Distortion correction