Optimizing design of inorganic scintillator optical fiber X-ray sensors

Abstract

In this paper, two approaches have been adopted to optimize the design of optical fiber X-ray sensors (OFXS). One approach involves using the hemisphere tip structure OFXS, while the other considers increasing the embedding depth of the scintillator in the embedded structure OFXS. The four OFXS designs considered include a 1 mm diameter hemispherical tip structure as well as embedded structure OFXSs with embedding depths of 1 mm, 3 mm, and 5 mm. Experimental results indicate that all four OFXSs exhibit a dose linearity above 0.999938 and dose rate linearity above 0.99991. The optical signal generated by hemisphere tip structure OFXS is 2–3 times higher compared to the embedded structure OFXSs. In the case of the embedded OFXS, increasing the embedding depth cannot effectively improve its sensitivity. And when measuring percentage depth dose (PDD) characteristics, no significant difference was observed for the four OFXSs. In addition, compared to the PDD curve measured using ionization chamber (IC), all OFXS exhibit an over-response phenomenon. These results show that the over-response phenomenon is not related to the structure of OFXS or the volume of scintillator, but only to the scintillator material. Therefore, subsequent calibration of OFXS needs to focus on studying the luminescence characteristics of the scintillator.