Stacked Crystal Array for Photon Detection
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Solution Overview
Problem
Existing radiation detection instruments for cancer treatment, particularly those using semiconductor or scintillating materials, face challenges with high-energy radiation detection due to the need for thick, expensive crystals with low production yield and high operating voltage, which poses safety hazards and cost inefficiencies.
Innovation Solution
A stacked crystal array comprising thin, electrically connected crystal slices in a parallel configuration, which provides photon absorption comparable to a monolithic crystal with reduced bias voltage requirements and increased production yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a monolithic thick crystal is used for high-energy radiation detection, then photon absorption efficiency is improved, but production cost increases and production yield decreases
Solution Approach 1:
The patent divides a thick monolithic crystal into multiple thinner crystal slices stacked together. Each slice is approximately 0.5-2 cm thick, which is optimal for production yield. The slices are arranged in series configuration to achieve the total thickness (e.g., 6-10 cm) needed for high-energy photon absorption, thereby combining the advantages of both thin slices (high production yield) and thick crystal (high absorption efficiency).
2Measurement precision
If a monolithic thick crystal is used for high-energy radiation detection, then photon absorption efficiency is improved, but operating voltage increases creating safety hazards
Solution Approach 1:
The thick crystal is segmented into multiple thinner slices, each requiring lower bias voltage (e.g., 50-200 V per slice) compared to a monolithic thick crystal (e.g., 1000-5000 V). The slices are connected in series electrically, so the total operating voltage remains sufficient for detection while each individual slice operates at a safer, lower voltage level, reducing electrical safety hazards.
3Measurement precision
If a monolithic thick crystal is used for high-energy radiation detection, then photon absorption efficiency is improved, but device cost increases
Solution Approach 1:
Thick crystals have low production yield and high cost. By segmenting the thick crystal into multiple thinner slices (each 0.5-2 cm), the production yield for each slice increases significantly, reducing the cost per slice. The stacked array of multiple slices achieves the same total absorption efficiency as a monolithic thick crystal but at a lower overall cost due to higher manufacturing efficiency of thinner slices.
4Productivity
If thin crystal slices are used instead of monolithic thick crystal, then production yield increases and cost decreases, but photon absorption efficiency decreases
Solution Approach 1:
Multiple thin crystal slices are combined in a stacked array configuration. Each slice contributes to the total photon absorption capability. The slices are arranged in series both physically and electrically, so their absorption efficiencies combine to match or exceed that of a monolithic thick crystal, while maintaining the production advantages of thinner slices.
5Productivity
If thin crystal slices are stacked in parallel configuration, then production yield increases, but the electrical connection complexity increases
Solution Approach 1:
The patent uses a series electrical configuration rather than parallel, connecting the thin slices sequentially. This series arrangement simplifies the electrical connection scheme compared to parallel configurations, as it requires fewer interconnect elements and simpler wiring. Each slice is connected to the next in sequence, reducing the overall electrical connection complexity while maintaining the production yield benefits of using multiple thin slices.
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 stacked crystal array achieves efficient high-energy radiation detection with lower production costs and safer operating voltages, enhancing the ability to locate sentinel lymph nodes during cancer surgery.
Implementation Method 1
An output signal is produced when an incoming photon collides with material within the detector
Implementation Method 2
a scintillating material such as or cesium iodide
Data Source
AI summary
A stacked crystal array includes a plurality of crystal slices and a plurality of interconnects. The interconnects have electrically conductive, spaced-apart and generally parallel elements joined by electrically conductive spacers extending generally orthogonally therebetween, the spacers being rotationally offset from each other by a predetermined angle. The array further includes a plurality of electrical insulators and an electrically insulative housing having a plurality of slots. The crystal slices, insulators and interconnects are arranged in the housing to form an assembly wherein the crystal slices are coupled together in a parallel electrical circuit. The assembly provides photon absorption comparable to a monolithic crystal having a thickness generally equivalent to the sum of the thicknesses of the crystal slices, but at a lower bias voltage.