Ceramic Scintillator Array Thermal Stability
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Solution Overview
Problem
The dimensional accuracy and stability of ceramic scintillator arrays in X-ray detectors are compromised due to temperature-induced dimensional changes, leading to reduced resolution and potential peeling of reflective layers, which affects the accuracy of X-ray CT images.
Innovation Solution
A ceramic scintillator array design featuring scintillator segments made from rare earth oxysulfide phosphor ceramics with a specific composition and reflective layers containing inorganic particles dispersed in transparent resins, where the second reflective layer has a glass transition point of 30°C or lower to minimize warpage and peeling, and the first reflective layer has a glass transition point of 50°C or higher to control dimensional changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a ceramic scintillator array is used in an X-ray detector, then light emission efficiency is improved, but dimensional accuracy deteriorates due to temperature-induced expansion and contraction
Solution Approach 1:
The patent applies parameter changes by carefully controlling the glass transition points of the transparent resins in the reflective layers. The first reflective layer uses resin with Tg ≥ 50°C to maintain dimensional stability at operating temperatures, while the second reflective layer uses resin with Tg ≤ 30°C to prevent peeling. This parameter optimization resolves the contradiction between maintaining high light emission efficiency and preserving dimensional accuracy under temperature variations.
Solution Approach 2:
The patent employs composite materials by combining reflective layers with transparent resins and reflective particles in specific configurations. The dual-reflective-layer structure with differently formulated resins creates a composite system that simultaneously achieves dimensional stability (first layer) and adhesion (second layer), thereby maintaining both manufacturing precision and light emission efficiency.
2Measurement precision
If the pitch between adjacent detection elements is reduced to increase resolution, then measurement precision is improved, but dimensional stability worsens due to greater sensitivity to thermal expansion
Solution Approach 1:
The patent addresses this contradiction by optimizing the glass transition parameters of the resin materials. By selecting resins with appropriate Tg values (≥50°C for the first layer, ≤30°C for the second layer), the patent minimizes thermal expansion effects, thereby maintaining dimensional stability even when the pitch between detection elements is reduced for higher resolution.
3Power
If the scintillator array is heated to improve light output, then energy conversion is improved, but warpage and peeling occur due to thermal expansion
Solution Approach 1:
The patent resolves this contradiction by controlling the glass transition parameters of the resin materials in the reflective layers. The first reflective layer's resin (Tg ≥ 50°C) prevents warpage by maintaining dimensional stability during heating, while the second reflective layer's resin (Tg ≤ 30°C) prevents peeling by allowing controlled thermal expansion. This enables the scintillator array to achieve high light output while maintaining structural integrity.
Solution Approach 2:
The reflective layers act as intermediary elements between the scintillator segments and the external environment. By carefully selecting resin materials with specific glass transition points, these intermediary layers mediate the thermal effects, allowing the scintillator array to convert energy efficiently into light output while preventing structural damage from thermal expansion.
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
This design enhances the dimensional stability and light output of the scintillator array, reducing pitch shifts and warpage, thereby improving the resolution and accuracy of X-ray images while preventing peeling of the reflective layers, even under temperature fluctuations.
Implementation Method 1
The X-ray incident on the scintillator segment is converted into visible light
Implementation Method 2
the detection element converts the visible light into an electric signal
Implementation Method 3
a structure that confines light generated by the incident X-ray in the scintillator segments so as to prevent the light from passing through an X-ray incident surface
Implementation Method 4
expansion of the reflective layer due to heating and contraction due to a decrease in temperature occur to cause a small dimensional change
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The ceramic scintillator array 1 according to an embodiment of the present invention is equipped with a plurality of scintillator segments 2 comprising a sintered compact of a rare earth oxysulfide phosphor; first reflection layers 3 interposed between adjacent scintillator segments 2; and a second reflection layer 4 disposed on the surface of the plurality of scintillator segments 2 upon which X-rays are incident. The difference between the dimensions of the ends of the surface of the second reflection layer 4 and the dimensions of the surface of the second reflection layer 4 when most convex is no more than 30 µm.