Scintillation Crystal Growth via Czochralski Method
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Solution Overview
Problem
Current methods for growing scintillation crystals face challenges such as non-uniform light yield and decay time due to uneven distribution of co-doped non-rare earth cations, and the high-temperature annealing process extends the production cycle while improving performance only by 15-30%, necessitating improved crystal growth techniques.
Innovation Solution
A method involving preprocessing operations like roasting and ingredient mixing, followed by controlled crystal growth using the Czochralski technique with precise temperature and gas flow management to optimize the growth of scintillation crystals, ensuring uniformity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If co-doped divalent or trivalent non-rare earth cations are introduced into the crystal, then the decay time of the scintillation crystal is decreased, but the light yield of the crystal is affected and the distribution of light yield and decay time becomes non-uniform
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific co-doped cations (Mg, Ca, Zn, Yb, Dy, Pb, Tb, Li, Na) at controlled concentrations to optimize the balance between decay time and light yield uniformity. This involves adjusting doping concentrations and ratios to achieve desired performance characteristics while maintaining uniform distribution.
Solution Approach 2:
The patent applies local quality by creating specific doping zones or gradients within the crystal structure. By controlling the spatial distribution of co-doped cations, the patent achieves optimized local properties that balance fast decay time with uniform light yield across different regions of the crystal.
2Manufacturing precision
If high-temperature annealing operation is performed on the oxide crystals, then the light yield and performance of the crystals are improved, but the preparation cycle is extended
Solution Approach 1:
The patent applies preliminary action by optimizing the crystal growth process itself to achieve better initial uniformity and performance characteristics. By pre-establishing the desired properties during growth through controlled doping and growth conditions, the patent reduces or eliminates the need for subsequent high-temperature annealing treatments, thereby shortening the overall preparation cycle.
Solution Approach 2:
The patent extracts or removes the high-temperature annealing step from the processing sequence by achieving the desired crystal performance directly through optimized growth conditions. This eliminates the time-consuming annealing operation while maintaining or improving crystal quality.
3Productivity
If co-doped non-rare earth cations are introduced to improve decay time, then the efficiency and speed of capturing high-energy photons is improved, but the cost of crystal production and screening increases
Solution Approach 1:
The patent optimizes composition parameters by selecting from multiple types of co-doped cations (Mg, Ca, Zn, Yb, Dy, Pb, Tb, Li, Na) and adjusting their concentrations to achieve the desired balance between performance and manufacturability. This involves finding optimal doping levels that provide sufficient performance improvement without excessive complexity in production and screening.
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 approach results in scintillation crystals with improved light yield, reduced decay time, and enhanced radiation hardness, while also reducing production costs and cycle time, achieving better performance consistency.
Implementation Method 1
activating the crystal growth device to execute a crystal growth to grow the crystal based on Czochralski technique
Implementation Method 2
the first preprocessing operation includes a roasting operation under 800℃～1400℃
Data Source
AI summary
The present disclosure relates to a method for growing a crystal. The method includes: weighing reactants according to a molar ratio of the reactants according to a reaction equation for generating the crystal after a first preprocessing operation is performed on the reactants, wherein the first preprocessing operation includes a roasting operation under 800° C.˜1400° C.; placing the reactants on which a second preprocessing operation has been performed into a crystal growth device, wherein the second preprocessing operation includes at least one of an ingredient mixing operation or a pressing operation at room temperature; introducing a flowing gas into the crystal growth device after sealing the crystal growth device; and activating the crystal growth device to execute a crystal growth to grow the crystal based on Czochralski technique.