Quantifying neutron scintillator screens with X-ray computed tomography

Abstract

As nondestructive imaging techniques become more commonplace, imaging systems must be improved and optimized to meet the growing demand. One key aspect of neutron imaging systems is the scintillator, which determines the time necessary to acquire an image and can also limit the spatial resolution achievable by a system. In this work, X-ray computed tomography was coupled with image processing to measure parameters of a boron-based neutron scintillator screen. The screen's surface and subsurface were examined for defects and a thickness measurement as a function of position was also successfully implemented. Higher resolution scans of a sub-volume of the scintillator coating enabled visualization of the packing of the converter and phosphor powders while also revealing microscopic porosity within the scintillator material. The converter-to-phosphor ratio was quantified with the examined area showing a ZnS:Ag phosphor volume of approximately 60.70% of the entire scintillator volume, while Na10B5O8 converter accounted for approximately 38.76% of the volume.