Quantitative Evaluation of Imaging Characteristics of the Neutron Image Intensifiers

A vacuum-tube type neutron image intensifier (NII), composed of Gd or 10B neutron convertor, is considered to have better spatial resolution and better detection efficiency compared with a traditional neutron scintilator. However, quantitative evaluation of difference in sensitivity among these imagers and difference in characteristics of the images between two NIIs has not been done since it needs measurements under the same irradiation condition. In this study we carried out radiography experiments at Hokkaido University Neutron Source (HUNS). Firstly, neutron radiography images were obtained by Gd-type NII, 10B-type NII, and the traditional neutron scintillator; NE426 (ZnS:Ag/6LiF). Next, we evaluated the brightness values from these images. We also evaluated the contrast and the image quality from two NIIs. The brightness of Gd-type NII is 8.8 times and the 10B-type is 12.9 times higher than the NE426. There is contrast little difference between the two types of NII. The image quality of Gd-type is better than 10B-type when exposure time is short.