Magnetic Field Generator Bore Access Inversion for NMR Sensitivity
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Solution Overview
Problem
Existing magnetic field generators for NMR apparatuses face challenges in accommodating the tuning circuit due to space constraints, leading to increased transmission line lengths and reduced sensitivity of NMR signals due to stray capacitance.
Innovation Solution
A magnetic field generator design with a cylindrical superconductor and a cold head extension portion, allowing the room temperature bore space to be accessed from both ends, enabling the tuning circuit to be positioned closer to the detection coil and facilitating external operation, thereby reducing transmission line length and improving sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sample tube is inserted into the room temperature bore space from the upper end, then the sample tube can be properly positioned, but the detection unit cannot be inserted due to space occupation by the sample tube
Solution Approach 1:
The patent enables the detection unit to be inserted from the lower end of the room temperature bore space, which is opposite to the conventional upper-end insertion method. This inversion is made possible by extending the cold head to the lower end and providing a lower communication space that allows access from below, thereby resolving the space conflict with the sample tube and enabling proper installation of the detection unit.
2Measurement precision
If the detection unit is inserted from the upper end of the room temperature bore space, then it can be positioned near the measurement sample, but the transmission line length increases and sensitivity decreases
Solution Approach 1:
The patent inverts the insertion direction of the detection unit from the conventional upper-end approach to a lower-end approach. By extending the cold head to the lower end and creating a lower communication space, the detection unit can be inserted from below and positioned optimally near the measurement sample. This reduces the transmission line length between the detection coil and tuning circuit, thereby minimizing stray capacitance and improving NMR signal sensitivity.
3Temperature
If the cold head is arranged in the entire lower region of the superconductor, then cooling is effective, but the lower region of the room temperature bore space is closed and inaccessible
Solution Approach 1:
The patent segments the cold head structure into two parts: an upper cold head portion that contacts the superconductor for effective cooling, and a lower cold head extension portion that extends downward to the lower end of the superconductor. This segmentation allows the lower end to be accessible for inserting the detection unit while maintaining cooling effectiveness through the extension portion, thereby resolving the contradiction between cooling performance and accessibility.
4Device complexity
If the room temperature bore space is closed at the lower end by the cold head, then the structure is simplified, but the detection unit cannot be inserted from the lower end
Solution Approach 1:
The patent inverts the conventional design by making the lower end of the room temperature bore space accessible rather than closed. The cold head extension portion is extended to the lower end, and a lower communication space is provided to allow insertion of the detection unit from below. This inversion maintains structural simplicity while enabling the detection unit to be inserted from the lower end, reducing transmission line length and improving sensitivity.
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 configuration enhances the installation workability of the tuning circuit and detection coil, reduces stray capacitance, and maintains or improves the sensitivity of the NMR signal by minimizing the distance between the detection coil and the tuning circuit.
Implementation Method 1
a refrigerating machine (10) configured to generate cooling energy; a cold head (20), through which the cooling energy generated by the refrigerating machine (10) is to be transmitted
Implementation Method 2
a superconductor (40), which is formed in a cylindrical shape, and is configured to generate a magnetic field by capturing a magnetic field under a state in which the superconductor (40) has been cooled to a temperature equal to or lower than a superconducting transition temperature
Data Source
AI summary
A magnetic field generator includes a refrigerating machine, a cold head, a superconductor which is formed in a cylindrical shape, a cold head extension portion which extends from the cold head and is brought into thermal contact with the superconductor at its extended end; and a vacuum heat insulating container having an internal space in which the cold head, the cold head extension portion, and the superconductor are received. The superconductor has a room temperature bore space, which is formed on its inner peripheral side along an axial direction of the superconductor, and is spatially isolated from the internal space of the vacuum heat insulating container. The room temperature bore space has both ends communicating to an outside of the magnetic field generator.