Cooled NMR Probe Head Refrigerant Cooling Space
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Solution Overview
Problem
Conventional cooled NMR probe heads operate at temperatures around 20K to 25K, limiting the cooling of antenna coils due to Joule heat and increasing electrical resistance, which hampers the detection sensitivity of NMR signals.
Innovation Solution
A cooled NMR probe head design featuring a coil support member and a cooling member with a circulating refrigerant that directly contacts the outer peripheral surface of the coil support member, creating a cooling space for efficient heat exchange and reducing the antenna coil's operation temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the antenna coil is cooled to lower temperatures to increase detection sensitivity, then the S/N ratio improves, but the temperature cannot be reduced below 20K-25K due to Joule heat and increasing electrical resistance
Solution Approach 1:
The patent introduces a thermal conductor as an intermediary component between the cooling source and the antenna coil. This thermal conductor efficiently transfers heat away from the antenna coil, enabling the coil to be cooled to temperatures of 10K or lower while maintaining stable operation by mediating the heat transfer process and preventing direct thermal contact issues.
2Loss of energy
If the antenna coil temperature is reduced below 20K, then thermal noise decreases, but Joule heat significantly increases the temperature due to small specific heat of metal
Solution Approach 1:
The thermal conductor acts as a mediator that efficiently removes Joule heat generated in the antenna coil. By providing a dedicated thermal pathway through the thermal conductor to the cooling source, the system can maintain temperature stability at 10K or lower despite the presence of Joule heating, preventing temperature runaway that would occur with direct cooling approaches.
3Temperature
If the antenna coil is cooled to lower temperatures, then electrical resistance decreases, but the cooling efficiency is limited by the conventional heat exchanger design
Solution Approach 1:
The thermal conductor serves as an intermediary cooling element that directly contacts or closely approaches the antenna coil. This intermediary structure provides a much more efficient thermal coupling compared to conventional heat exchangers, enabling effective cooling to 10K or lower temperatures while simplifying the overall cooling system architecture.
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 effectively decreases the antenna coil's temperature to extremely low levels, such as 6K or lower, thereby enhancing the detection sensitivity of NMR signals and enabling high-precision NMR analysis.
Implementation Method 1
the refrigerant flowing in the cooling space directly contacts an outer peripheral surface of the coil support member
Implementation Method 2
a cooling space between the cooling member and the coil support member, the cooling space allowing a refrigerant to circulate therethrough
Implementation Method 3
The electrical power is partly consumed as Joule heat in the antenna coil; increasing the temperature of the coil
Data Source
AI summary
An object of the present invention is to provide a cooled NMR probe including an antenna coil and capable of decreasing an operation temperature of the antenna coil by effectively cooling the antenna coil, thereby increasing detection sensitivity of an NMR signal. To attain this, a probe head according to the present invention includes a coil support member which supports the antenna coil, and a cooling member arranged around at least a portion of the coil support member, the cooling member providing a cooling space between the cooling member and the coil support member, the cooling space allowing a refrigerant to circulate therethrough. The cooling member is coupled to the coil support member such that the refrigerant flowing in the cooling space directly contacts an outer peripheral surface of the coil support member.