Garnet Scintillator Material for X-ray Detection
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Solution Overview
Problem
Current solid state scintillators used in X-ray CT apparatuses and security systems face challenges in achieving high sensitivity and reducing afterglow time while maintaining cost-effectiveness, with cadmium tungstate being environmentally hazardous and rare earth oxysulfide ceramics having limitations in cost and characteristics.
Innovation Solution
A solid state scintillator material with a garnet structure composition of (Gd1-α-β-γTbαLuβCeγ)3(Al1-xGax)aOb, where α, β, and γ are within specific atomic ratios, incorporating Gd, Tb, Lu, Ce, Al, and Ga to enhance X-ray absorption, light emission, and reduce afterglow, while minimizing impurities and hetero-phase precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If monocrystalline cadmium tungstate is used as solid state scintillator, then cost is reduced, but environmental harm increases due to cadmium being a noxious substance
Solution Approach 1:
The patent replaces expensive and environmentally hazardous monocrystalline cadmium tungstate with cost-effective polycrystalline rare earth oxide ceramics that have comparable or superior performance characteristics, eliminating the need for harmful cadmium while maintaining economic viability
Solution Approach 2:
The patent uses composite polycrystalline rare earth oxide ceramics containing multiple elements (Gd, Tb, Lu, Ce) in specific ratios to achieve the desired balance of performance, cost, and environmental compatibility, replacing single-material cadmium tungstate with a multi-component alternative
2Reliability
If rare earth oxysulfide ceramics are used as solid state scintillator, then sensitivity is improved, but cost increases and afterglow time is not sufficiently reduced
Solution Approach 1:
The patent modifies the chemical composition parameters by using rare earth oxide ceramics with specific elemental ratios (Gd1-α-β-γTbαLuβCeγ) instead of traditional oxysulfide compositions, achieving improved sensitivity while controlling cost through optimized material formulation
Solution Approach 2:
The patent employs composite rare earth oxide ceramics containing Gd, Tb, Lu, and Ce elements in controlled amounts to achieve superior sensitivity and shorter afterglow time compared to conventional materials, while maintaining cost-effectiveness through efficient use of rare earth elements
3Illumination intensity
If rare earth oxide ceramics with garnet structure are used as solid state scintillator, then light output is improved, but scan time cannot be sufficiently reduced due to insufficient sensitivity and afterglow time
Solution Approach 1:
The patent optimizes the composition parameters of rare earth oxide ceramics by incorporating specific ratios of Gd, Tb, Lu, and Ce elements to simultaneously enhance light output and reduce afterglow time, enabling faster scanning while maintaining high sensitivity
Solution Approach 2:
The patent uses composite rare earth oxide ceramics with optimized elemental composition to achieve both high light output for improved sensitivity and short afterglow time for reduced scan time, resolving the contradiction between these performance parameters
4Object-affected harmful factors
If X-ray exposure dose is reduced to minimize radiation to subject, then sensitivity of scintillator must be increased to maintain image quality
Solution Approach 1:
The patent changes the material composition parameters by using rare earth oxide ceramics with specific elemental ratios to increase X-ray absorption coefficient and improve sensitivity, enabling reduced exposure doses while maintaining adequate image quality
Solution Approach 2:
The patent employs composite rare earth oxide ceramics with optimized composition to enhance X-ray absorption and sensitivity, allowing the system to detect lower radiation doses while maintaining image quality, thus reducing radiation exposure to the subject
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 proposed scintillator material achieves high sensitivity, short afterglow time, and improved light output, enabling faster scanning and reduced X-ray exposure doses with enhanced cost-effectiveness and environmental sustainability.
Implementation Method 1
a solid state scintillator which emits visible light when excited by X-rays
Implementation Method 2
an X-ray detector in which plural X-ray detecting elements are arranged
Data Source
AI summary
In an embodiment, a solid state scintillator material includes a composition represented by a general formula: (Gd1-α-β-γTBαLuβCeγ)3(Al1-xGax)aOb, where α and β are numbers satisfying 0<α≦0.5, 0<β≦0.5, and α+β≦0.85, γ is a number satisfying 0.0001≦γ≦0.1, x is a number satisfying 0<x<1, a is a number satisfying 4.8≦a≦5.2 and b is a number satisfying 11.6≦b≦12.4 (atomic ratio), and a garnet structure.