Semiconductor Detector Pixel Cluster Geometry for Spectral Resolution
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Solution Overview
Problem
Conventional semiconductor detectors face challenges in achieving optimal sensitivity and spectral information extraction due to the interaction of ionizing radiation, particularly in high resistivity materials like CdTe and GaAs, where the detector geometry and pixel size affect signal processing and energy resolution.
Innovation Solution
The method involves designing semiconductor detectors with a large plurality of pixels, where a single interaction event produces a detectable signal across a cluster of at least three adjacent pixels, allowing for controlled geometry to correlate energy with cluster size and simplify signal processing, enabling direct measurement of spectral information without binning radiation into energy bins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detector uses a large plurality of small pixels, then the spectral information extraction is improved, but the device complexity increases
Solution Approach 1:
The detector surface is divided into a large plurality of small pixels, each capable of independently detecting signals. This segmentation allows the detector to capture detailed spatial distribution of charge clouds, enabling spectral information extraction through cluster size analysis while maintaining manageable complexity through systematic pixel addressing
Solution Approach 2:
The invention transitions from traditional energy binning methods to a spatial dimension approach by analyzing the spatial distribution of signals across multiple pixels. Cluster size (number of pixels activated) serves as a proxy for energy measurement, adding a spatial dimension to energy spectroscopy and simplifying the readout electronics
2Measurement precision
If the pixel size is made very small, then the energy resolution is improved, but the signal processing complexity increases
Solution Approach 1:
Instead of requiring precise measurement of signal amplitude in each pixel, the invention uses a simplified approach by counting the number of pixels activated (cluster size). This partial measurement approach provides sufficient energy resolution while dramatically reducing signal processing complexity compared to traditional methods
Solution Approach 2:
The invention changes the measurement parameter from signal amplitude to spatial cluster size. By counting how many pixels are activated by a single interaction event, the system achieves energy resolution through a different physical parameter that is simpler to process electronically
3Reliability
If the detector geometry is optimized for high resistivity materials like CdTe and GaAs, then the detection sensitivity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The detector employs different pixel sizes in different regions or different pixel dimensions (e.g., non-square pixels) to optimize performance for specific energy ranges or interaction types. This local optimization allows high sensitivity for high resistivity materials while accommodating manufacturing tolerances through region-specific design adjustments
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
This approach enhances energy resolution and improves information content by correlating cluster sizes with incident radiation energy, allowing for improved detection and imaging applications, particularly in high-energy electromagnetic radiation, such as gamma-ray detection.
Implementation Method 1
Ionising radiation interacts with the detector medium (such as Si, Ge, GaAs, CdTe, CZT and a few others) and a number of electron-hole pairs proportional to the deposited energy is produced
Implementation Method 2
Under the influence of the electrical field created inside the detector, the electrons and holes drift apart towards collecting electrodes
Implementation Method 3
the electrons and holes drift along the electrical field lines as charge clouds, which expand due to Coulomb repulsion
Data Source
AI summary
A method of fabricating a semiconductor detector device to exhibit a target sensitivity to incident radiation in a predetermined energy range is described, the method comprising: providing a semiconductor detector; defining on a detector surface of the semiconductor detector a large plurality of pixels; wherein the detector is geometry is controlled with reference to the size of the said pixels such that a single interaction event in the predetermined energy range will produce a detectable signal in each of a plurality of adjacent pixels making up a cluster of at least three pixels. A detector fabricated by such a method and a method of obtaining spectral information about incident radiation using such a detector are also described.