Polycrystalline Scintillator for Soft X-Ray Detection
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Solution Overview
Problem
Current scintillators for X-ray detection lack sufficient absorption of soft X-rays and emission intensity while exhibiting high afterglow, making them unsuitable for clear imaging of low-density tissues in X-ray CT scans.
Innovation Solution
A polycrystalline scintillator with a garnet crystal structure comprising Y, Gd, Al, Ga, and O, with specific atomic ratios and minor amounts of Ce, Lu, Sc, Fe, and Si, optimized for large soft X-ray absorption and low hard X-ray absorption, achieving high emission intensity and reduced afterglow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional scintillators are used, then detection capability is maintained, but soft X-ray absorption is insufficient and emission intensity is low
Solution Approach 1:
The patent changes the chemical composition parameters of the scintillator by incorporating specific elements (Y, Gd, Al, Ga, O) in defined atomic ratios to optimize both soft X-ray absorption and emission intensity. The garnet crystal structure with these specific compositional parameters enables simultaneous improvement of absorption coefficient and emission characteristics.
Solution Approach 2:
The patent uses a composite scintillator material combining multiple elements (Y, Gd, Al, Ga, O) in a garnet crystal structure. This composite approach allows the material to exhibit both high soft X-ray absorption capability and high emission intensity, resolving the contradiction between absorption and emission properties.
2Reliability
If conventional scintillators are used, then detection function is provided, but afterglow is high reducing image quality
Solution Approach 1:
The patent modifies the compositional parameters of the scintillator material, specifically controlling the atomic ratios of Y, Gd, Al, Ga, and O in the garnet structure. These parameter changes result in reduced afterglow while maintaining detection function, as the specific composition optimizes the luminescence decay characteristics.
3Measurement precision
If scintillator size is reduced for improved resolution, then spatial resolution increases, but detection sensitivity decreases
Solution Approach 1:
The patent enhances the intrinsic properties of the scintillator material through compositional parameter changes, increasing emission intensity and absorption efficiency. This allows smaller scintillator crystals to maintain or improve detection sensitivity, enabling better spatial resolution without sacrificing sensitivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The scintillator provides high resolution imaging of low-density tissues with enhanced emission intensity and minimized afterglow, suitable for X-ray CT applications.
Implementation Method 1
the scintillator absorbs X-rays to emit light
Implementation Method 2
the scintillator absorbs X-rays to emit light, which is detected by the silicon photodiode
Data Source
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AI summary
A polycrystalline scintillator for detecting soft X-rays, which comprises Ce as a light-emitting element and at least Y, Gd, Al, Ga and O, and has a garnet crystal structure, and a composition represented by the general formula of (Y1-x-zGdxCez)3+a(Al1-uGau)5-aO12, wherein 0 ≤ a ≤0.1, 0.15 ≤ x ≤ 0.3, 0.002 ≤ z ≤ 0.015, and 0.35 ≤ u ≤ 0.55, with 0.05-1 ppm by mass of Fe and 0.5-10 ppm by mass of Si by outer percentage, a ratio µ50/µ100 of 3 or more, wherein µ50 is an absorption coefficient of X-rays at 50 keV, and µ100 is an absorption coefficient of X-rays at 100 keV, and afterglow of 800 ppm or less after 3 ms from the termination of X-ray irradiation.