Crosslinked Plastic Scintillator Neutron Gamma Discrimination
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Solution Overview
Problem
Current plastic scintillators face challenges in effectively discriminating between fast neutrons and gamma rays, suffering from instability, bleaching, and deformation over time, which affects their performance in neutron detection, particularly in large-volume applications like radiation detection portals.
Innovation Solution
A plastic scintillator material with a crosslinked polymer matrix, incorporating a fluorescent compound at high concentration, using alkyl diacrylates or alkyl dimethacrylates as crosslinking agents, which maintains transparency and stability, allowing for effective discrimination between neutron and gamma signals without aging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plastic scintillator uses a non-crosslinked polymer matrix with fluorescent compounds, then it achieves initial scintillation performance and transparency, but it suffers from instability, bleaching, and deformation over time
Solution Approach 1:
The patent changes the chemical structure and crosslinking degree of the polymer matrix as key parameters. By using a crosslinked polymer matrix with specific crosslinking density and incorporating fluorescent compounds at optimized concentrations, the material achieves both initial performance and long-term stability, preventing bleaching and deformation while maintaining scintillation properties
Solution Approach 2:
The patent creates a composite material system combining a crosslinked polymer matrix with fluorescent compounds. This composite structure leverages the mechanical stability and chemical resistance of the crosslinked network while incorporating the optically active fluorescent molecules, achieving synergistic effects that resolve the contradiction between initial performance and long-term stability
2Reliability
If a plastic scintillator incorporates fluorescent compounds at high concentration, then it achieves good scintillation properties, but it causes strong degradation of physicochemical behavior including bleaching and deformation
Solution Approach 1:
The patent optimizes the concentration parameter of fluorescent compounds within a specific range (0.1-5% by weight) and adjusts the crosslinking density of the polymer matrix to counterbalance the degrading effects. This parameter optimization allows high enough fluorescent compound content for good scintillation while preventing excessive bleaching and deformation through the stabilizing crosslinked network
3Reliability
If a plastic scintillator uses a crosslinked polymer matrix, then it achieves stability and rigidity, but it may reduce transparency at the emission wavelength
Solution Approach 1:
The patent carefully controls the crosslinking degree and selects crosslinking agents with appropriate molecular structures to minimize light absorption. By optimizing these parameters, the crosslinked matrix maintains its stabilizing effect while preserving sufficient transparency at the fluorescent compound emission wavelengths, resolving the contradiction between mechanical stability and optical clarity
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 provides a stable, transparent, and rigid scintillator material that maintains excellent discrimination and scintillation properties over time, enabling the production of large-volume scintillators suitable for long-term use in neutron and gamma detection without degradation.
Implementation Method 1
a plastic scintillator material comprising a polymeric matrix in which is incorporated at least one fluorescent compound
Implementation Method 2
plastic scintillators comprise fluorescent molecules fixed in a polymer having properties of transparency at their own emission wavelength
Implementation Method 3
the polymer matrix consists of a crosslinked polymer obtainable by polymerization of a mixture comprising at least one aromatic monomer and at least one monomer playing the role of crosslinking agent
Data Source
Figure 1~2
Figure 3~4
AI summary
A plastic scintillator material comprising a polymer matrix in which there is incorporated at least one fluorescent compound having a mass concentration greater than equal to 10% by mass of the total mass of the material, in which the polymer matrix consists of a crosslinked polymer likely to be obtained by polymerisation of a mixture comprising at least one aromatic monomer and at least one monomer acting as crosslinking agent chosen from alkyl diacrylates, alkyl dimethacrylates, and the mixtures thereof, the molar proportions of the monomer acting as crosslinking agent and the aromatic monomer in the mixture being 10% to 50% and 90% to 50% respectively. A plastic scintillator prepared by shaping said material. A method for distinguishing between a signal caused by fast neutrons, optionally a signal caused by thermal neutrons, and a signal caused by gamma rays in radiation comprising fast neutrons, optionally thermal neutrons, and gamma rays emitted by a mixed source, which involves exposing the plastic scintillator to said radiation emitted by the mixed source and separating the signal caused by fast neutrons from the signal caused by gamma rays, and optionally from the signal caused by thermal neutrons by Pulse Shape Discrimination (PSD).