Neutron flat-panel detector using In-Ga-Zn-O thin-film transistor.

Neutron imaging is a powerful tool for observing the internal structure of an object without destroying the object. Neutron imaging (neutron radiography) is a prominent application of neutrons but still requires significant improvements, for example, in sensitivity, resolution, radiation hardness, and handling of neutron imaging detectors. This paper presents the development and the first neutron imaging results of a neutron flat-panel detector (nFPD) based on an In-Ga-Zn-O (IGZO) thin-film transistor (TFT)/photodiode array coupled with a LiF/ZnS scintillator sheet. Direct photo-coupling to the scintillator increases the light collection efficiency. Moreover, unlike lens-coupled neutron cameras, the proposed detector is compact and easy to handle. Owing to the high off-state resistance of IGZO TFTs, their leakage current is lower than that of conventional TFTs, enabling the IGZO TFTs to hold an accumulated charge for a longer period of time and allowing longer exposure times for imaging. This would be a powerful feature for imaging at compact neutron sources with limited flux. This paper reports on the first neutron imaging results with an IGZO nFPD, its performance evaluation, and a demonstration of three-dimensional computed tomography with neutrons.