Influence of powder particle size and scintillator layer thickness on the performance of GdOS:Tb scintillators for neutron imaging

Yasuda, Ryo; Katagiri, Masaki*; Matsubayashi, Masahito  

GdOS:Tb scintillator has much higher neutron-capture cross-section than ZnS/LiF commonly used in neutron radiography. Characteristics of those scintillators correlate to some material parameters including scintillator-thickness and powder-size. Three types of GdOS:Tb scintillator with different particle size were prepared, and effects of the powder size and thickness on the scintillator characteristics were evaluated using a sensitivity indicator (SI) and a beam purity indicator (BPI). Intensity of scintillation increases as the particle size increases. In addition, the intensity was saturated at a thickness each scintillator. It is considered that those phenomena are caused by difference in the packing rate of powder near substrate and flight path of thermal neutrons and internal conversion electrons in the scintillator.