Nanostructured Anodes for Portable Radiation Detectors
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Solution Overview
Problem
Conventional proportional radiation counters require high stable voltage sources, limiting their portability and sensitivity, and there is a need for detectors that are portable, efficient, and can operate on portable power supplies with reduced electromagnetic noise.
Innovation Solution
The use of nano-sized anodes made from carbon nanofibers, carbon nanotubes, and nano-sized silicon, fabricated using techniques like plasma enhanced chemical vapor deposition and reactive ion etching, to create arrays with controlled spacing that reduce the voltage bias required for operation and enhance detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional proportional radiation counters use high stable voltage sources to achieve proportional counting region, then detection sensitivity is improved, but device portability and electromagnetic noise performance deteriorate
Solution Approach 1:
The patent changes the physical parameters of the anode by using nanostructured materials (carbon nanofibers, carbon nanotubes, nano-sized silicon) with diameters in the range of 100-200 nanometers. This parameter change in anode geometry creates sufficiently high electrical fields at lower operating voltages, enabling proportional counting without requiring high stable voltage sources, thus improving portability while maintaining detection sensitivity
Solution Approach 2:
The patent applies local quality enhancement by creating nanostructured anodes with specific local geometric features (vertical alignment, controlled spacing of 1-10 microns,尖端 structures) that concentrate electrical field lines at critical locations. This local field enhancement allows the system to achieve proportional counting conditions in specific regions without requiring uniformly high voltage across the entire detector, reducing overall voltage requirements and electromagnetic noise
2Power
If conventional proportional radiation counters use high voltage to produce sufficient electrical field for gas multiplication, then charge amplification is improved, but electromagnetic noise and power consumption increase
Solution Approach 1:
The patent changes the electrical field distribution parameters by introducing nanostructured anodes with dimensions of 100-200 nanometers diameter and spacing of 1-10 microns. These parameter changes create intense localized electrical fields that enable gas multiplication and charge amplification at much lower operating voltages, thereby reducing electromagnetic noise and power consumption while maintaining detection capability
Solution Approach 2:
The patent utilizes the curved geometry of nanostructured anodes (carbon nanofibers, carbon nanotubes, nano-sized silicon structures) to concentrate electrical field lines at the curved surfaces and tips. This curvature effect creates high field strength regions that facilitate electron avalanche formation and charge amplification without requiring high voltage, thus reducing electromagnetic noise while maintaining power 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
This approach allows for portable radiation detectors with high detection efficiency and reduced electromagnetic noise, achieving similar performance to helium-3 gas proportional counters without the need for helium, and enabling extended operation on portable power supplies.
Implementation Method 1
Gas multiplication is the result of increasing the electrical field within the PC to a sufficiently high value such that the ionized radical interacts with the fill gas causing a secondary ionization. This results in a cascade of ionization events, forming an electron avalanche that is detected at the anode
Implementation Method 2
providing metal catalyst locations on the substrate using plasma enhanced chemical vapor deposition; and, forming the carbon fibers on the surface of substrate
Implementation Method 3
fabricated using techniques like plasma enhanced chemical vapor deposition and reactive ion etching, to create arrays with controlled spacing
Data Source
AI summary
Anodes for proportional radiation counters and a process of making the anodes is provided. The nano-sized anodes when present within an anode array provide: significantly higher detection efficiencies due to the inherently higher electric field, are amenable to miniaturization, have low power requirements, and exhibit a small electromagnetic field signal. The nano-sized anodes with the incorporation of neutron absorbing elements (e.g., 10B) allow the use of neutron detectors that do not use 3He.