Room: Track 1
Purpose: To evaluate the performance enhancement of benchtop x-ray fluorescence (XRF) imaging system by using the latest generation single crystal cadmium telluride (CdTe) detector.
Methods: The new CdTe detector was characterized to operate at a higher bias voltage of 700V and fast (3.2µs) peaking time. The Compton/XRF spectra from small (8 mm in diameter) gold nanoparticle (GNP)-containing samples were acquired with our experimental XRF imaging system using the new detector as well as the old/existing detector. During these measurements, detector collimators made of two different aperture sizes (2 and 3 mm) were used. The gold K-shell XRF signals were extracted from acquired spectra and used to determine the calibration curve for each experimental condition.
Results: The new detector produced relatively lower dead time under high x-ray flux, suggesting its improved photon counting efficiency. Additionally, the new detector was stable with no signs of polarization and performed well with the spectral resolution of 0.7keV FWHM at 69keV photon energy. Using the identical (2mm aperture) detector collimator, the new detector scored nearly 50% more gold XRF signal than the old detector at all GNP concentrations tested. This feature of the new detector resulted in the sensitivity enhancement, giving rise to the GNP detection limit of 0.02wt.% which was lower than that (0.03wt.%) achievable with the old detector. The new detector also allowed further improvements, when combined with the detector collimator with a larger (3mm) aperture. Under this condition, the new detector produced drastically more gold XRF signal at a given GNP concentration (e.g., 9 times more for 1.0wt.% GNP solution), leading to further reduction in the GNP detection limit (i.e., 0.01wt.%).
Conclusion: Significant performance enhancement of our experimental benchtop XRF imaging system, in terms of the system sensitivity and scan time, was achieved by adopting the latest generation single crystal CdTe detector.
Funding Support, Disclosures, and Conflict of Interest: Supported by NIH/NIBIB R01EB020658