Silicon SSPM Micro-Pixel Arrays for PET/MRI Radiation Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current position-sensitive solid-state photomultipliers (SSPMs) face challenges such as high cost, complex implementation, and incompatibility with magnetic fields, limiting their use in applications like PET/MRI systems, where they are needed for advanced radiation detection and imaging.
Innovation Solution
The development of integrated silicon solid-state photomultiplier devices operable in Geiger mode, featuring an array of p-n micro-pixels with a signal division network and processing units to provide position-sensitive output signals, enabling efficient radiation detection and imaging without the limitations of traditional PMTs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional photomultiplier tubes (PMTs) are used for radiation detection, then high detection capability is achieved, but the devices become bulky, expensive, and incompatible with magnetic fields
Solution Approach 1:
The patent replaces traditional vacuum tube photomultiplier tubes with solid-state silicon photomultiplier devices. This substitution eliminates the bulky vacuum tube structure while maintaining photodetection capability through solid-state p-n micro-pixel arrays operated in Geiger mode, achieving compact size and compatibility with magnetic fields
Solution Approach 2:
The patent changes the operational parameters by operating silicon photodiodes in Geiger mode with specific bias voltages (e.g., 30V) to achieve avalanche breakdown and high gain (10^6), transforming standard photodiodes into high-sensitivity photomultiplier equivalents with improved timing resolution and magnetic field compatibility
2Device complexity
If silicon solid state photomultipliers are used, then compact size and magnetic field compatibility are achieved, but position sensitivity and signal processing capability are reduced
Solution Approach 1:
The patent divides the photodetector into an array of p-n micro-pixels (e.g., 4×4 or larger) on a single chip. Each micro-pixel can be independently addressed and its position identified through signal division networks, enabling position-sensitive detection while maintaining compact solid-state architecture
Solution Approach 2:
The patent introduces signal division networks with resistive dividers and charge-sensitive preamplifiers as intermediary components between the micro-pixel array and readout electronics. These intermediaries enable precise position determination by distributing and measuring signals from activated micro-pixels, achieving Anger logic-based position sensitivity
3Device complexity
If PIN photodiodes and APDs are used for PET detectors, then compact solid-state structure is achieved, but gain and timing capability are insufficient
Solution Approach 1:
The patent changes the operational mode from linear photodiode operation to Geiger mode by applying higher bias voltages to achieve avalanche breakdown. This parameter change enables internal gain of 10^6 and improved timing resolution through the characteristic fast rise time of Geiger-mode avalanches, while maintaining compact solid-state structure
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
These devices offer improved cost-effectiveness, precision, and compatibility with magnetic fields, enabling their use in diverse applications including PET/MRI systems, with enhanced energy and timing resolution, and the ability to generate high-resolution images.
Implementation Method 1
a pixel unit including an array of more than 2×2 p-n micro-pixels on a planar substrate
Implementation Method 2
an integrated silicon SSPM device operable in a Geiger mode
Data Source
AI summary
An integrated silicon solid state photomultiplier (SSPM) device includes a pixel unit including an array of more than 2×2 p-n photodiodes on a common substrate, a signal division network electrically connected to each photodiode, where the signal division network includes four output connections, a signal output measurement unit, a processing unit configured to identify the photodiode generating a signal or a center of mass of photodiodes generating a signal, and a global receiving unit.