Development and x-ray imaging performance of Tb-doped GdAlO3-αAl2O3 submicron-diameter phase-separated scintillator fibers

Abstract

Scintillators are key components in high-energy x-ray detectors for x-ray computed tomography, which are applied in medical diagnosis, nondestructive testing, and security inspection. Scintillators in x-ray imaging are required to have both high spatial resolution and sensitivity; however, a trade-off between spatial resolution and sensitivity exists. To improve the sensitivity of a scintillator, its thickness must be increased; however, spatial resolution deteriorates with increasing thickness. Here, we developed a well-aligned Tb-doped GdAlO3- αAl2O3 phase-separated scintillator fiber (PSSF) with a diameter of 1.25- μm by a micro-pulling-down method. The luminescence, scintillation, and imaging performances of a grown PSSF sample were evaluated. X-ray-induced radioluminescence measurements of the sample showed Tb3+ 4f–4f emissions in the wavelength range of 470–700 nm, and the maximum emission peak was at 550 nm. The contrast transfer function at 10 lp/mm was 82% for both 270 and 500 μm-thick PSSF samples. We calculated the luminescence index, which is the product of the scintillator’s light yield and sensitivity, of the samples and compared their values with commercially available conventional CsI:Tl columnar scintillators. The Tb-doped GdAlO3- αAl2O3 PSSF exhibits higher contrast transfer function and luminescence index values at above 60 keV x-ray region compared with the tested conventional scintillators.

A high-resolution real-time imaging system for observing the trajectories of neutron induced particles in a scintillator

“…We previously combined a fiber-structured scintillator plate and a high-sensitivity CCD camera to observe the trajectories of alpha particles [16,17]. We also developed a high-resolution, real-time performance evaluation system of scintillators for X-rays by combining scintillators with a highsensitivity CCD camera [19,20]. We conjectured that these systems could be applied to imaging the trajectories of neutron induced particles if we employed the system in combination with a Li-ZnS(Ag) plate.…”

Sub-micrometer real-time imaging of trajectory of alpha particles using GAGG plate and CMOS camera

“…The imaging system adopted a magnifying unit commonly used to measure high-resolution transmission images combined with synchrotron radiations that can achieve sub-micrometer spatial resolution [13]. The magnifying unit was also used for a high-efficiency performance-evaluation system of scintillators for X-rays [14,15].…”

Direct fabrication of pixelated detector arrays for high-energy x-ray imaging via additive manufacturing

“…Non-destructive quality assurance via high-energy x-ray imaging is limited by the poor efficiency of the commercial Gadox screens [5,6]. Amorphous silicon arrays with structured scintillators such as patterned Gd2O2S:Tb phosphor screens and GdAlO3-αAl2O3 fiber arrays have been explored, with the goal of improving resolution and efficiency [7][8][9]. Lu2O3:Eu and (Gd,Lu)2O:Eu (GLO) have been demonstrated to improve efficiency for lens-coupled imaging due to their higher density, which results in higher stopping power for high-energy applications [10][11][12][13][14][15].…”