Cold-Bore NMR Cryostat Layout for Vacuum-Stable Precision Measurement
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Solution Overview
Problem
Conventional NMR measuring arrangements face challenges in achieving high magnetic field strengths and precise measurements due to the risk of vacuum breakdown when changing NMR probes, leading to increased heat load and quenching of superconducting magnetic coils.
Innovation Solution
The NMR measuring arrangement features a cryostat with only one evacuated gap between the magnetic coil system and the bore wall, thermally coupled to a heat sink, eliminating conventional sheet metal radiation shields to minimize heat input and allow for a closer proximity of the magnetic coil system to the sample, thereby enhancing magnetic field generation and measurement precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multiple sheet metal radiation shields are arranged between the vacuum container and magnetic coil system, then thermal insulation is improved, but device complexity and space occupation increase
Solution Approach 1:
The invention extracts and eliminates the sheet metal radiation shields from the cryostat structure. Instead of using multiple shields, the patent relies on the evacuated gap alone for thermal insulation, thereby reducing device complexity while maintaining insulation performance
Solution Approach 2:
The invention merges the functions of multiple components into a simpler structure. The evacuated gap simultaneously provides thermal insulation and creates space for the magnetic coil system to be positioned closer to the sample, eliminating the need for separate radiation shields
2Temperature
If sheet metal radiation shields are used, then thermal insulation is improved, but the magnetic coil system must be positioned farther from the sample, reducing magnetic field strength
Solution Approach 1:
By removing the radiation shields, the magnetic coil system can be positioned closer to the sample without compromising thermal insulation, thereby increasing the magnetic field strength at the sample position
Solution Approach 2:
The invention changes the thermal insulation approach from using intermediate shield structures to using the evacuated space dimension directly, allowing the magnetic coil system to occupy the space previously taken by shields and thus be closer to the sample
3Adaptability or versatility
If NMR probe is changed by inserting into the bore, then measurement versatility is improved, but vacuum integrity may be compromised, leading to heat load increase
Solution Approach 1:
The magnetic coil system is pre-cooled to cryogenic temperatures before the NMR probe is inserted. This preliminary cooling ensures that even if vacuum integrity is temporarily compromised during probe insertion, the heat load on the coil system is minimized because the coil is already at low temperature
Solution Approach 2:
The cryostat is designed with the magnetic coil system already in place and cooled beforehand, providing a cushion against potential vacuum breaches during probe changes. The system is prepared in advance to withstand temporary vacuum compromises without quenching
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 enables more precise NMR measurements with higher spectral resolution and signal-to-noise ratio by reducing heat input and maintaining the vacuum integrity, allowing for efficient magnetic field generation and sample measurement without quenching.
Implementation Method 1
the cryostat, for the thermal insulation of the magnetic coil system, locally forms one or more evacuated gaps between the superconducting magnetic coil system and the vacuum container
Implementation Method 2
at least one segment of the wall of the bore is thermally coupled to a heat sink of the cryostat
Implementation Method 3
Magnetic fields with high field strengths for NMR measurements are often generated with superconducting magnetic coil systems
Implementation Method 4
superconducting magnetic coil systems must be kept at a cryogenic temperature
Data Source
AI summary
An NMR measuring arrangement (20) includes a cryostat (1), a superconducting magnet coil system (2) and an NMR probe (3). The cryostat has an evacuated vacuum container (5) and forms a bore (10). A wall (12) of the bore delimits the vacuum container. The cryostat forms only one evacuated gap (13) in a space (18) between the magnet coil system and the wall of the bore. At least a segment of the wall of the bore is thermally coupled to a heat sink of the cryostat. As a result, the NMR measurement arrangement provides more precise NMR measurements (in particular with a higher spectral resolution and/or a higher signal-to-noise ratio) on measurement samples.