A novel ratiometric optical fiber X-ray sensor based on NaGdF4:Tb/CaAl2O4:Eu/Nd composites

Abstract

X-ray imaging technology has become ubiquitous in medical diagnosis and security inspections. However, the high X-ray radiation dose rates associated with these applications pose significant health risks. Despite this, there remains a lack of convenient and accurate X-ray detection methods in the commercial market. In response, a novel ratiometric optical fiber X-ray sensor based on a NaGdF₄:15Tb nanoparticle and CaAl₂O₄:Eu/Nd phosphor integrated film is developed. This sensor enables accurate dose rate detection with high sensitivity and robust stability across various environmental conditions. The diverse absorption coefficients of the studied materials are the primary contributors to the recorded different dose rate-dependent X-ray excited optical luminescence intensity variations. The maximum absolute radiation dose rate sensitivity and relative radiation dose rate sensitivity achieved are 0.098 (nGy s⁻¹)⁻¹ and 9.06% (nGy s⁻¹)⁻¹, respectively. The measured detection limit is as low as 15 nGy s⁻¹. This advancement holds great promise for monitoring X-ray dose rates to mitigate radiation risks and pave the way for the development of new X-ray detection systems with high accuracy.