NMR Probe Head Cooling Layout to Minimize Vibration Interference
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Solution Overview
Problem
Conventional NMR apparatuses face challenges with liquid cryogen dependence, leading to frequent interruptions, high costs, and inadequate infrastructure issues, along with inefficient cooling systems that cause mechanical and magnetic disturbances, and are difficult to maintain or retrofit.
Innovation Solution
A compact NMR apparatus with a cryocooler housed separately from the cryostat, using thermally insulated suspension tubes and radiation shields for efficient cooling of both the magnet system and NMR probe head, allowing independent cooling mechanisms and reducing vibration and magnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid cryogens are used to cool the magnet system, then cooling effectiveness is improved, but operational continuity deteriorates due to frequent refilling interruptions
Solution Approach 1:
The system uses a cryocooler to automatically reliquefy evaporated cryogen within the sealed container, eliminating the need for external refilling operations and enabling continuous measurement without interruption
Solution Approach 2:
Instead of discarding evaporated cryogen, the system recovers it by capturing and reliquefying the vapor through the cryocooler, maintaining a closed-loop cryogen management system
2Temperature
If separate cooling systems are used for the magnet system and probe head, then cooling performance is improved, but device complexity and cost increase
Solution Approach 1:
A single cryocooler unit performs multiple cooling functions by sequentially or simultaneously cooling both the magnet system and the probe head, eliminating the need for separate cooling systems
Solution Approach 2:
The cooling functions for the magnet system and probe head are merged into one integrated cryocooler system, reducing overall system complexity while maintaining effective cooling of both components
3Volume of moving object
If the cryocooler is integrated inside the cryostat, then space efficiency is improved, but mechanical and magnetic disturbances increase
Solution Approach 1:
The cryocooler is extracted from the interior of the cryostat and placed in an external housing, removing the source of mechanical vibrations and magnetic interference from the sensitive NMR measurement environment
4Temperature
If rigid mounting of the probe head is used for cooling, then thermal contact is improved, but maintenance flexibility deteriorates
Solution Approach 1:
The probe head mounting is changed from a rigid fixed connection to a dynamic removable connection, allowing the probe head to be easily detached and reattached while maintaining effective thermal contact during operation
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 minimizes mechanical and magnetic disturbances, enables flexible operation, reduces cryogen loss, and allows for easy maintenance without interrupting measurements, while being cost-effective and suitable for various spectroscopy methods.
Implementation Method 1
at least one cold stage of the cold head is thermally conductingly connected to a heat-transferring device
Implementation Method 2
at least one cooling circuit with a refrigerant is disposed between the cooling device and the NMR probe head
Implementation Method 3
the first cryocontainer is installed in an evacuated outer jacket
Implementation Method 4
is surrounded by at least one radiation shield
Data Source
AI summary
An NMR apparatus comprising an NMR magnet system disposed in a first cryocontainer (2) of a cryostat (9), and an NMR probe head (1), wherein the first cryocontainer (2) is installed in an evacuated outer jacket and is surrounded by a radiation shield (24) and/or a further cryocontainer (3), wherein a cooling device is provided for cooling the NMR probe head (1) and a cryocontainer (2, 3), which comprises a cold head (4, 4a, 4b, 4c) with several cold stages (12a, 12b, 12c, 18a, 18b, 18c, 19a), wherein one cold stage (12a, 12b, 12c, 18a, 18b, 18c, 19a) is connected to a heat-transferring device, and wherein a cooling circuit is provided between the cooling device and the NMR probe head (1), is characterized in that the cooling device is disposed in a separate, evacuated housing (6) which is positioned directly above the cryostat (9), wherein the heat-transferring device is inserted directly into suspension tubes (29a, 29c) of the cryocontainer (2, 3) and/or is in contact with the radiation shield (24). This effects a simple construction that is efficient for cooling an NMR apparatus.