Copper Lithium Heptaborate Phosphor for 3D Dosimetry
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Solution Overview
Problem
Existing thermoluminescent dosimeters face challenges in accurately measuring three-dimensional dose distribution due to overlapping emission intensity distributions, low emission intensity, and absorption of thermoluminescence by binders, requiring complex corrections and inadequate heat resistance.
Innovation Solution
A thermoluminescent phosphor comprising copper-containing lithium heptaborate with a monomodal emission intensity distribution in a visible range, resistant to heat, and suitable for use with epoxy resin binders, eliminating the need for near-infrared cut filters and simplifying dose calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manganese-containing lithium tetraborate is used as thermoluminescent material, then tissue equivalence is achieved, but emission intensity distribution overlaps with heating-caused emission requiring complex corrections
Solution Approach 1:
The patent changes the chemical composition parameters by using copper-containing lithium heptaborate instead of manganese-containing lithium tetraborate, and adjusts the emission wavelength range to 400-600 nm to separate from heating-caused emission, thereby eliminating the need for complex corrections while maintaining tissue equivalence
Solution Approach 2:
The patent converts the potential harm of heating-caused emission overlap into a benefit by carefully selecting the emission wavelength range (400-600 nm) that does not overlap with heating-caused emission, thereby simplifying the measurement process while maintaining accuracy
2Illumination intensity
If copper-containing lithium triborate is used as thermoluminescent material, then emission intensity is improved, but emission intensity is still insufficient and requires resin binders that absorb thermoluminescence
Solution Approach 1:
The patent uses copper-containing lithium heptaborate as a composite material that combines high emission intensity with appropriate optical properties, achieving both improved emission intensity and reduced absorption by resin binders compared to previous materials
Solution Approach 2:
The patent changes the material composition from copper-containing lithium triborate to copper-containing lithium heptaborate, which fundamentally alters the optical properties and emission characteristics to achieve higher emission intensity with lower resin absorption
3Measurement precision
If thermoluminescent material with high emission intensity is used, then measurement accuracy is improved, but heat resistance becomes insufficient requiring complex corrections
Solution Approach 1:
The patent changes the thermal properties of the thermoluminescent material by selecting copper-containing lithium heptaborate which maintains high emission intensity while providing sufficient heat resistance to withstand the heating process without requiring complex corrections
4Reliability
If conventional thermoluminescent materials are used, then dosimeter function is achieved, but binder absorption of thermoluminescence requires complex corrections
Solution Approach 1:
The patent changes the optical parameters of the thermoluminescent material by using copper-containing lithium heptaborate with emission in the 400-600 nm range, which reduces absorption by epoxy resin binders, thereby maintaining dosimeter function while eliminating the need for complex corrections
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 thermoluminescent phosphor provides high emission intensity in a visible range, resistant to heat, allowing accurate three-dimensional dose distribution measurement without complex corrections and binder absorption, ensuring tissue equivalence and effective dosimeter performance.
Implementation Method 1
a thermoluminescent phosphor comprising copper-containing lithium heptaborate... the distribution of the emission intensity of thermoluminescence versus wavelength is a sole and monomodal distribution and is present in a visible range of wavelengths shorter than 600 nm
Data Source
Figure 1
Figure 2(A)~2(B)
Figure 3(A)~4(B)
AI summary
There is provided a thermoluminescent phosphor characterized in that a distribution of the emission intensity of thermoluminescence is present in a visible range that does not overlap the peak of the heating-caused emission intensity of the thermoluminescent phosphor itself and also has one peak within a temperature range in which a resin to be used as a binder can resist heat optically. There is also provided a method of producing the thermoluminescent phosphor. More specifically, there are provided a thermoluminescent phosphor that comprises lithium heptaborate as a base material and copper as a luminescent center present in the base material and which is characterized in that the distribution of the emission intensity of thermoluminescence versus temperature is a sole and monomodal distribution within the range of from 45°C to 130°C, and a method of producing the thermoluminescent phosphor.