Radiation detector based on liquid crystal light valve for large-area imaging applications

Currently most large-area radiation detectors rely on the use of a phosphor screen and an optical sensor. In such conversion process, there will be signal loss due to inefficiencies in coupling between phosphor screen and later light-detection components. This paper presents a radiation detector based on X-ray induced light transmittance of liquid crystal (LC) as a function of radiation. Our detector incorporates a europium-doped gadolinium oxide (Gd2O3:Eu) phosphor and an amorphous selenium (a-Se)-coupled LC light valve. The Gd2O3:Eu is synthesized using a low-temperature solution–combustion method, and the optical properties of the Gd2O3:Eu are investigated as a function of a sintering temperature. The transmission–voltage (T–V) curve and the optical response of the detector are also investigated. Our experimental results show good T–V characteristics of the LC, switching between 12% and 86% transmission. The radiation dose is also presented in this work. The results show that our detector can operate at low X-ray dose and, therefore, a promising application is the medical-imaging detector.