Optical Fiber-Scintillator Coupling With Two-Section Hole Geometry
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Solution Overview
Problem
Existing methods for connecting optical fibers to scintillators in radiation detection devices often result in fiber breakage and inefficient light transfer due to inadequate hole design and adhesive application, leading to instability and reduced light transmission.
Innovation Solution
A method involving the creation of two coaxially drilled holes in the scintillator with specific diameters and depths, followed by precise polishing and insertion of the optical fiber, and application of adhesive with matching refractive index to ensure a stable and efficient light transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single hole is drilled in the scintillator for optical fiber insertion, then the connection process is simple, but the optical fiber is prone to breakage and light transfer efficiency is reduced
Solution Approach 1:
The single hole is divided into two sequential drilling operations: first a larger diameter hole is drilled to a certain depth, then a smaller diameter hole is drilled coaxially to the full required depth. This segmentation allows the optical fiber to be inserted through the smaller hole while the larger hole provides adhesive space, preventing fiber breakage and improving connection reliability without excessive complexity
Solution Approach 2:
The smaller diameter hole is nested within the larger diameter hole, creating a concentric structure where the inner hole guides the optical fiber and the outer hole provides structural support and adhesive containment. This nested configuration ensures proper fiber positioning and prevents breakage while maintaining manufacturing feasibility
2Strength
If adhesive is applied generously to ensure fiber insertion, then the fiber is securely held, but light transmission efficiency decreases due to refractive index mismatch
Solution Approach 1:
Adhesive is applied selectively only in the annular space between the optical fiber surface and the hole wall, rather than coating the entire fiber or hole. This localized application ensures mechanical bonding strength while minimizing the adhesive volume that would cause light scattering and refractive index mismatch, thus preserving light transmission efficiency
Solution Approach 2:
The adhesive serves as an intermediary material with refractive index optimized to match both the scintillator and optical fiber materials. By using an adhesive whose refractive index falls between those of the scintillator and fiber, light transmission is maintained while still providing adequate bonding strength
3Loss of energy
If the hole diameter is made small to match the fiber core, then light transfer efficiency improves, but the fiber becomes difficult to insert and alignment precision requirements increase
Solution Approach 1:
The hole creation process is segmented into two stages: first a larger pilot hole is drilled to facilitate easy fiber insertion and alignment, then a smaller precision hole is drilled coaxially to optimize light transfer. This segmentation allows the fiber to be easily inserted through the larger initial hole while the final smaller hole ensures optimal light transmission efficiency
Solution Approach 2:
The larger diameter hole is drilled first as a preliminary step to guide the optical fiber into the scintillator with proper alignment. This preliminary hole makes insertion easier and ensures correct positioning before the final smaller hole is drilled to optimize light transfer efficiency
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 method provides a durable connection that minimizes fiber breakage and enhances light transmission efficiency from the scintillator to the optical fiber, suitable for radiation detection applications.
Implementation Method 1
application of adhesive with matching refractive index to ensure a stable and efficient light transfer
Data Source
Figure 1~3
AI summary
A method of connecting an optical fiber to a scintillator, where a centrally positioned isocentric hole with a circular cross-section is created in the scintillator, consisting of two sections: a shallower section with a diameter D1 that is at least 30% larger than the diameter of the optical fiber, and a deeper section with a smaller diameter D2 matching the core diameter of the optical fiber plus an additional 0.1 - 0.2 mm. The total depth of the isocentric hole constitutes 15 - 30% of the scintillator's height. An optical fiber, polished to an optical-quality finish, is inserted into the hole and adhesively bonded to the scintillator using an optical adhesive with a refractive index close to that of the scintillator and optical fiber, ideally between 1.56 and 1.58.