Fiber Optic Plate Neutron Imaging Resolution
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Solution Overview
Problem
Current neutron imaging technologies suffer from limited efficiency, spatial resolution, and light output due to thickness-related light loss and broadening, making them unsuitable for effective neutron imaging applications outside high energy physics.
Innovation Solution
A chalcopyrite or colquiriite neutron absorber loaded glass or plastic scintillator based fiber optic plate using LiInSe2, grown via the micro-pulling-down technique, is developed, which provides a low spatial resolution limit and high efficiency for thermal and fast neutron imaging by employing a parallel array of optical fibers with a binder and diffuse reflective material, coupled with a CCD array for enhanced light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick scintillator detectors are used to improve neutron detection efficiency, then thermal neutron efficiency improves, but spatial resolution deteriorates due to light broadening as it traverses from interaction point to readout
Solution Approach 1:
The scintillator is divided into many thin optical fiber segments (e.g., 50-100 μm diameter) arranged in a parallel array, rather than using a single thick scintillator block. This segmentation maintains high neutron detection efficiency through sufficient total thickness while preserving spatial resolution by limiting light travel distance within each fiber segment.
Solution Approach 2:
Optical fibers serve as intermediary waveguides that transmit scintillation light from the neutron interaction point directly to the readout mechanism with minimal broadening. The fiber optic structure acts as a mediator that preserves spatial information while enabling efficient neutron detection through the scintillator material.
2Manufacturing precision
If thin scintillator detectors are used to improve spatial resolution, then spatial resolution improves, but neutron detection efficiency deteriorates due to insufficient interaction probability
Solution Approach 1:
Multiple thin scintillator layers are segmented and arranged in parallel arrays, with each layer providing high spatial resolution while the collective array provides sufficient total thickness for high neutron detection efficiency. The segmentation allows independent optimization of resolution and efficiency.
Solution Approach 2:
The solution transitions from a single thick scintillator volume to a three-dimensional array of thin optical fibers. This dimensional reorganization allows the system to achieve both high spatial resolution (in the transverse direction) and high detection efficiency (through the longitudinal arrangement of multiple fibers).
3Manufacturing precision
If conventional CCD readouts are used with fine pixilation to achieve high resolution, then spatial resolution improves, but device complexity and manufacturing difficulty increase due to photolithography limits and ASIC pixel size constraints
Solution Approach 1:
Optical fibers serve as intermediaries that decouple the scintillator interaction region from the readout mechanism. This allows the use of conventional, less complex CCD readouts with larger pixels while maintaining high spatial resolution through the fiber optic waveguide structure, avoiding the need for fine-pixelated ASICs or complex photolithography.
Solution Approach 2:
The solution replaces direct electronic readout requirements (which demand fine pixelation and complex ASIC fabrication) with an optical readout system using fiber optic waveguides. This substitution enables high resolution imaging using more manufacturable, conventional CCD technology.
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 achieves 50 μm resolution with 82% thermal neutron efficiency and >1% fast neutron efficiency, offering superior light output and fast signal readout, suitable for both direct and mirrored imaging setups, utilizing existing CCD readouts common in the medical industry.
Implementation Method 1
LiInSe2 is a neutron detecting material that exhibits both semiconductor and scintillator properties
Implementation Method 2
Fluoride and oxide scintillating compounds containing a neutron sensitive material (e.g., Li6 or B10) may also be used
Implementation Method 3
Each of the plurality of optical fiber segments is derived from one or more elongate optical fibers manufactured using a micro-pulling-down technique
Implementation Method 4
A diffuse reflective material is optically coupled to the plurality of first ends of the plurality of optical fiber segments
Implementation Method 5
a binder material disposed between and coupling the plurality of optical fiber segments together
Data Source
AI summary
A chalcopyrite, colquiriite, neutron absorber loaded glass, or plastic scintillator based fiber optic plate for use in a neutron imaging system, including: a plurality of optical fiber segments disposed side-by-side adjacent to one another in a parallel array; and a binder material disposed between and coupling the plurality of optical fiber segments together. A diffuse reflective material is optically coupled to the plurality of first ends of the plurality of optical fiber segments. An optical detector device is optically coupled to the plurality of second ends of the plurality of optical fiber segments opposite the diffuse reflective material. Optionally, the fiber optic plate further includes a diffuse reflective material disposed one or more of on an exterior surface of each of the plurality of optical fiber segments and between the plurality of optical fiber segments.