Investigation of the dosimetric characteristics of real-time silicone/Bi2O3 nanocomposites for the diagnostic level X-rays

Abstract This study presents the development of high-sensitivity real-time X-ray dosimeters based on room-temperature-vulcanized (RTV-2) silicone nanocomposites incorporating 0–60 wt% Bi 2 O 3 nanoparticles, fabricated via solution casting. Structural and morphological characterization using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) with elemental mapping, and elemental analysis confirmed the uniform dispersion of monoclinic Bi 2 O 3 nanorods within the amorphous RTV-2 matrix. Complementary Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and thermogravimetric analysis (TGA) validated the chemical integrity, thermal stability, and mechanical robustness of the resulting nanocomposites. Dosimetric performance was investigated under diagnostic-range X-ray exposure using a COMET MXR 320/26 source (dose rates: 2.8–12 mGy/min). The I-V characteristics at 4.8 mGy/min exhibited a highly linear response over ± 400 V. At 400 V, the photocurrent increased from ~ 0.56 nA (pure RTV-2) to ~ 1.66 nA (60 wt% Bi 2 O 3 ), corresponding to a ~ 3-fold enhancement in photocurrent. The devices demonstrated good short-term repeatability (standard deviation of 2.3% over ten consecutive measurements) and a signal-to-noise ratio (SNR) of up to ~ 1900 at 400 V. Compared with reported values for commercial MOSFET dosimeters (~ 0.1–1 nA/mGy) and previously reported Bi 2 O 3 -polymer systems, the developed nanocomposites exhibit a higher competitive normalized sensitivity (~ 0.35 nA/(mGy/min), or 878 nC·mGy⁻ 1 ·cm⁻ 3 on a volumetric basis), demonstrating their suitability as lead-free alternatives for low-dose, real-time diagnostic X-ray dosimetry; further evaluation of long-term stability and mechanical durability is needed to establish clinical applicability.