Improvement of Spatial Resolution of Time-Resolved MA-PMT Camera for Imaging of TRU Elements

The use of alpha autoradiography is ineffective for measuring plutonium (Pu) spots in a transuranic element containing alpha-radiator minor actinides. Therefore, the KURRILINAC team, Kyoto University has developed a non-destructive imaging system with pulsed neutron transmission spectroscopy. The system uses a high-efficiency bundle-type scintillator and a 16x16 ch multi-anode photo-multiplier tube (MA-PMT) and LiTime-Analyzer-12e (LiTA12e) processor as detector. The spatial resolution of this system was improved by 3 mm of MA-PMT to 1 mm of the scintillator by the center-of-gravity calculation of the LiTA12e system. However, a 1-mm spatial resolution is insufficient to detect the Pu spot of one of the TRU elements using the program. Therefore, we are developing a super-resolution technique with sub-pixel shifted images for the transmission images. The calculated reconstructed image, based on the use of four sub-pixel shifted X-ray transfer images, was obtained by simulation. This result suggests the spatial resolution of the imaging system will be improved by installing stepping motors in the platform of a measurement object.