Non-stoichiometric Rare-earth Halide Scintillator for Energy Resolution

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Solution Overview

Problem

Conventional rare-earth halide scintillating crystals face challenges with crystal growth defects and poor consistency due to doping with alkaline earth metal ions, which affect energy resolution and linearity, and co-doping with halogen ions complicates compositions and uneven ion distribution.

Innovation Solution

A non-stoichiometric rare-earth halide scintillating material with a chemical formula REaCebX3, where RE is La, Gd, Lu, or Y, and X is Cl, Br, or I, with a valence state between +2 and +3, using a +2 valent rare-earth halide as a dopant to replace heterogeneous alkaline earth metal halides, maintaining a stoichiometric crystal structure while improving energy resolution and linearity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If alkaline earth metal ions are doped into rare-earth halide crystals, then energy resolution and energy response linearity are improved, but crystal growth defects increase and doping concentration is limited

Engineering Contradiction:
Improveenergy resolutionVSAvoidcrystal growth defects
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters by introducing a non-stoichiometric rare-earth halide component (RE1-xMxBr3-yCyOy) with controlled deviations from ideal stoichiometry. This allows tuning of crystal lattice properties to accommodate dopant ions while maintaining crystal integrity, thus improving energy resolution without excessive defect formation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite doped crystal structure combining rare-earth halide base material (LaBr3, CeBr3, etc.) with alkaline earth metal dopants (Sr, Ba, Ca) and controlled stoichiometric deviations. This composite approach allows synergistic improvement of scintillation properties while managing crystal growth defects through compositional control

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If co-doping with halogen ions and alkaline earth metal ions is performed, then doping concentration increases and crystal growth defects are reduced, but composition becomes complicated and ion distribution becomes uneven

Engineering Contradiction:
Improvedoping concentrationVSAvoidcomposition complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent extracts and isolates the essential doping function to a single non-stoichiometric rare-earth halide component (RE1-xMxBr3-yCyOy), eliminating the need for separate co-doping of halogen and alkaline earth metal ions. This simplifies the overall composition while maintaining the ability to achieve high doping concentrations with uniform distribution

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses stoichiometric deviation parameters (x, y in RE1-xMxBr3-yCyOy) as control variables to achieve desired doping concentrations. By adjusting these compositional parameters, high doping levels are obtained without the complexity of multi-component co-doping systems

Inventive Principle:
Principle #35Parameter changes

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 solution enhances energy resolution, light yield, and decay time, reduces crystal growth defects, and improves homogeneity, resulting in a scintillating material with superior performance and simplified composition compared to conventional stoichiometric compounds.

Implementation Method 1

A scintillating material can be configured to detect such high-energy rays as α-rays, γ-rays, X-rays, and such high-energy particles as neutrons

Methodology Applied
Scientific EffectScintillation: Scintillation

Implementation Method 2

The rare-earth ion and alkaline earth metal ion in the doped LaBr3:Ce crystal are respectively in stable +3 valence and +2 valence

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentUS11512251B2Rare-earth halide scintillating material and application thereof
Publication Date: 2022.11.29 GRIREM ADVANCED MATERIALS CO LTD

AI summary

The present invention provides a rare-earth halide scintillating material and application thereof. The rare-earth halide scintillating material has a chemical formula of REaCebX3, wherein RE is a rare-earth element La, Gd, Lu or Y, X is one or two of halogens Cl, Br and I, 0≤a≤1.1, 0.01≤b≤1.1, and 1.0001≤a+b≤1.2. By taking a +2 valent rare-earth halide having the same composition as a dopant to replace a heterogeneous alkaline earth metal halide in the prior art for doping, the rare-earth halide scintillating material is relatively short of a halogen ion. The apparent valence state of a rare-earth ion is between +2 and +3. The rare-earth halide scintillating material belongs to non-stoichiometric compounds, but still retains a crystal structure of an original stoichiometric compound, and has more excellent energy resolution and energy response linearity than the stoichiometric compound.