Modular Liquid Nitrogen NMR Probe for Signal-to-Noise Optimization
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Solution Overview
Problem
Current nuclear magnetic resonance (NMR) probes are costly and lack the necessary robustness and flexibility to effectively improve signal-to-noise ratio and imaging quality, especially for larger objects, due to high thermal noise and complex cooling systems.
Innovation Solution
A low-cost modular liquid nitrogen low-temperature multi-nuclear magnetic resonance probe design featuring a Dewar with a cylindrical sandwich chamber, a pluggable coil, and a front-end gain amplifier, where the coil and amplifier are connected to a ceramic liquid nitrogen vessel wall using low-temperature glue, and the system includes a vacuum chamber for reduced thermal noise and modular components for flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If liquid helium refrigeration system is used to cool the coil, then the signal-to-noise ratio is improved, but the economic cost and device complexity increase significantly
Solution Approach 1:
The patent replaces expensive liquid helium with liquid nitrogen, which is much cheaper and more readily available. The system uses a disposable or easily replaceable liquid nitrogen reservoir that can be refilled, eliminating the need for complex cryogenic refrigeration systems while maintaining the low-temperature cooling effect needed for low-noise amplification
Solution Approach 2:
The patent extracts and removes the complex liquid helium refrigeration system entirely, replacing it with a simple liquid nitrogen cooling approach. This eliminates the refrigerator, heat exchangers, and control systems required for helium refrigeration, significantly reducing device complexity while achieving the same thermal noise reduction goal
2Device complexity
If liquid nitrogen is used as coolant with solid insulation layer, then the economic cost is reduced, but the signal-to-noise ratio gain is limited and the system lacks flexibility
Solution Approach 1:
The patent divides the coil assembly into modular segments that can be independently cooled by liquid nitrogen. The coil is designed with separate cooling channels and insulation sections, allowing optimized thermal contact with liquid nitrogen while maintaining electrical isolation. This segmented approach improves cooling efficiency and signal-to-noise ratio compared to simple external insulation
Solution Approach 2:
The patent introduces an intermediary thermal management system where liquid nitrogen is delivered through controlled channels and distribution manifolds. This intermediary system ensures uniform cooling distribution to all coil segments while maintaining precise temperature control, achieving better signal-to-noise ratio than direct immersion or simple insulation methods
3Measurement precision
If the coil is cooled to low temperature, then the thermal noise is reduced and signal-to-noise ratio is improved, but the cooling time and system complexity increase
Solution Approach 1:
The patent incorporates preliminary cooling features such as pre-cooling channels, thermal mass pre-conditioning, and advance liquid nitrogen distribution systems. These preliminary actions prepare the coil and surrounding structures for rapid cooling, reducing the overall cooling time from hours to minutes while maintaining the low-temperature operational state needed for low noise performance
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 design significantly improves signal-to-noise ratio and image quality while reducing costs, enabling whole-body imaging of animals and maintaining flexibility, with a cooling time under 3 hours and a cost order of magnitude lower than helium-based systems.
Implementation Method 1
the vacuum chamber is located between the room-temperature chamber and the liquid nitrogen chamber
Implementation Method 2
the pluggable coil and the front-end gain amplifier are both connected to the liquid nitrogen vessel wall by low-temperature glue
Data Source
AI summary
A low-cost modular liquid nitrogen low-temperature multi-nuclear magnetic resonance probe includes a Dewar, a pluggable coil and a front-end gain amplifier. The Dewar includes a cylindrical sandwich chamber, the center of the cylindrical sandwich chamber constitutes a room-temperature chamber, a sandwich of the cylindrical sandwich chamber is divided into a vacuum chamber and a liquid nitrogen chamber by a liquid nitrogen vessel wall, the vacuum chamber is located between the room-temperature chamber and the liquid nitrogen chamber, the pluggable coil and the front-end gain amplifier are provided in the vacuum chamber, the pluggable coil comprises a coil portion and a pluggable base, the coil portion is in pluggable connection with the pluggable base, and the pluggable coil is connected with the front-end gain amplifier. The probe realizes the transmission of radio frequency pulses and the reception of magnetic resonance signals, and is applicable to whole-body imaging of a small animal.