High-Sensitivity Room-Temperature Silicon Nanocomposites Developed for Real-Time X-Ray Dosimetry
Researchers have developed high-sensitivity, real-time X-ray dosimeters utilizing room-temperature-vulcanized silicone nanocomposites embedded with bismuth(III) oxide nanoparticles. Fabricated through solution casting with bismuth concentrations ranging from zero to 60 weight percent, the lead-free nanocomposites offer an alternative for low-dose diagnostic X-ray detection.
Structural and Thermal Integrity of Bismuth Nanorods
Characterization techniques including X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy confirmed the uniform dispersion of monoclinic bismuth oxide nanorods within the amorphous silicone matrix. Complementary Fourier-transform infrared spectroscopy, Raman spectroscopy, and thermogravimetric analysis validated the chemical integrity, thermal stability, and mechanical robustness of the resulting material.
Diagnostic-Range X-Ray Exposure and Photocurrent Performance
Dosimetric performance was tested under diagnostic-range X-ray exposure using a COMET MXR 320/26 source operating at dose rates between 2.8 and 12 mGy/min. Current-voltage characteristics measured at 4.8 mGy/min demonstrated a highly linear response over a span of plus or minus 400 volts.
At an applied voltage of 400 volts, the photocurrent scaled upward alongside the nanoparticle concentration. Pure silicone yielded approximately 0.56 nanoamperes, whereas the 60 weight percent bismuth oxide composite reached roughly 1.66 nanoamperes, representing a threefold enhancement in photocurrent output.
Normalized Sensitivity Versus Commercial MOSFET Dosimeters
The developed devices exhibited reliable short-term repeatability, marked by a standard deviation of 2.3 percent across ten consecutive measurements, alongside a signal-to-noise ratio of up to approximately 1,900 at 400 volts.
| Dosimeter Type | Sensitivity Metric | Signal Output / Performance |
|---|---|---|
| Commercial MOSFET | Standard Output | ~0.1–1 nA/mGy |
| 60 wt% Bi2O3 Nanocomposite | Normalized Sensitivity | ~0.35 nA/(mGy/min) or 878 nC·mGy⁻1·cm⁻3 |
Compared against reported values for commercial metal-oxide-semiconductor field-effect transistor dosimeters and previous bismuth-polymer systems, these nanocomposites show higher competitive normalized sensitivity. Further evaluation of long-term stability and mechanical durability remains necessary to establish clinical applicability.
