Design and development of FBG based load cell for weight monitoring of cesium pencil in radiation environment

This paper presents the design, analysis and development of a fiber Bragg grating (FBG) based load cell integrated with a titanium transducer for monitoring the weight of Cesium (Cs) pencils in radiation and elevated temperature environment. Finite element analysis was employed to evaluate strain transfer, with the FBG modeled as an equivalent axial spring. The simulation results were further used to optimize the cantilever geometry. The predicted load sensitivities were 4.82 pm/g, 1.83 pm/g, and 0.92 pm/g for thicknesses of 0.5 mm, 0.7 mm, and 1.0 mm, respectively. Prototypes with thicknesses of 0.7 mm and 1.0 mm were fabricated and experimentally evaluated, yielding sensitivities of 1.34 pm/g and 0.76 pm/g, respectively. The observed deviation between simulation and experimental results is attributed to incomplete strain transfer through the adhesive bonding layer. The developed FBG based load cell was optimized for measuring the weight of stainless steel containers containing vitrified Cs glass with a measurement range up to ~ 500 g and an accuracy of ± 5 g. The results confirm the suitability of the proposed FBG based load sensor for accurate and long-term operation in radiation environment.