Solution-Processed Neutron Detector on Flexible Substrate
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Solution Overview
Problem
Conventional neutron detectors are expensive to produce and have reduced efficiency due to gas leakage and the need for expensive semiconductor processing techniques, limiting their use in low-cost, high-volume applications such as detecting hazardous radioactive materials.
Innovation Solution
A low-cost neutron detector design featuring a sensor with a neutron capture layer formed using high atomic number metal semiconductor nanoparticles on a flexible substrate via low-temperature solution processing, enabling efficient roll-to-roll production and high sensitivity to thermal neutrons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tube-type neutron detectors use Helium-3 gas at high pressure to achieve high detection efficiency, then detection efficiency is improved, but production cost increases and gas leakage problems occur
Solution Approach 1:
The patent changes the physical state of the neutron capture material from gas (Helium-3) to solid (Boron-10), and changes the detection mechanism from direct gas ionization to semiconductor detection of capture reactions. This parameter change eliminates gas leakage issues while maintaining high detection efficiency through the solid-state Boron-10 layer coupled with a silicon photodiode sensor.
Solution Approach 2:
The patent replaces expensive Helium-3 gas with cheaper solid Boron-10 material that can be deposited as a thin layer. This substitution dramatically reduces material cost and eliminates the need for pressurized gas containment, making the detector much cheaper to manufacture while maintaining reliability.
2Reliability
If solid-state semiconductor-based neutron detectors use vapor deposited silicon layers, then detection efficiency is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent replaces complex vapor deposition manufacturing processes with simpler solution-based deposition methods. Instead of requiring high-vacuum semiconductor fabrication equipment, the invention uses solution-processed materials that can be deposited at lower costs and with less manufacturing complexity, while maintaining the solid-state detection efficiency.
3Measurement precision
If conventional neutron detectors use expensive semiconductor processing techniques, then detection precision is improved, but production cost increases
Solution Approach 1:
The patent substitutes expensive vapor-deposited silicon layers with cheaper solution-processed organic or hybrid materials that can achieve similar or better detection precision. These solution-processed materials eliminate the need for expensive semiconductor fabrication equipment and processes, dramatically reducing production costs while maintaining detection precision through optimized material composition and layer 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
The solution provides highly reliable, low-cost, and efficient neutron detection capabilities, facilitating the use of neutron detectors in distributed item-level tagging during shipping by utilizing flexible substrates and solution-processed sensor structures that operate similarly to photodiodes with enhanced sensitivity.
Implementation Method 1
neutron detection requires the use of a 'neutron capture' material (i.e., a material with a high neutron capture cross-section) that 'converts' neutrons into charged particles
Implementation Method 2
at least one of these materials includes high atomic number metal semiconductor nanoparticles, such as Cadmium-Selenide, Cadmium-Telluride (CdTe), lead sulfide (PbS) or other metal chalcogenides
Implementation Method 3
the holes and electrons are respectively conducted by the donor and acceptor materials to the electrodes
Data Source
AI summary
A low-cost neutron detector is formed on a substrate includes a sensor formed by an active material layer sandwiched between two electrodes, and a neutron capture layer formed in close proximity to (i.e., over and/or under) the sensor. The sensor active material layer includes a bulk heterojunction or bilayer structure that is formed by depositing particulate solutions incorporating at least one type of high atomic number nanoparticle using low-temperature (i.e., below 400° C.) solution processing techniques. The sensor electrode material and neutron capture material are similarly disposed in associated solutions (e.g., conductive inks) that are also deposited using low-temperature solution processing techniques, whereby the fabrication process can be carried out on low-cost flexible substrate material (e.g., PET) using high efficiency roll-to-roll production techniques. The neutron capture material is optionally patterned as an array of pillars, and the active layer materials are backfilled between the pillars.