NMR Spectrometer Lock Channel Frequency Correction
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Solution Overview
Problem
NMR spectrometers face challenges with magnetic field inhomogeneities and temperature variations, leading to frequency shifts and reduced spectral resolution due to the separation of lock and target samples in different magnetic field distributions, which existing methods struggle to compensate effectively.
Innovation Solution
A method involving a transfer function that correlates the resonance frequencies of a lock sample and a target sample, allowing for real-time compensation current adjustments to the compensation coil, enabling precise frequency correction of the target sample's excitation frequency, even when the lock and target coils are positioned separately within the magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If lock and target samples are positioned separately in different magnetic field distributions, then device flexibility and independent positioning are improved, but frequency correlation and measurement precision deteriorate
Solution Approach 1:
The patent introduces a compensation coil as an intermediary element that generates a compensating magnetic field to correct frequency shifts between lock and target samples. The compensation coil acts as a mediator that equalizes the magnetic field environment for both samples, enabling accurate frequency correlation despite their separate positioning in different magnetic field distributions
Solution Approach 2:
The system dynamically adjusts the current through the compensation coil to change the magnetic field parameters in real-time. By varying the compensation current based on detected frequency shifts, the system maintains accurate frequency correlation between lock and target samples while allowing flexible positioning
2Stability of the object's composition
If compensation coil current is increased to correct magnetic field variations, then frequency stability is improved, but magnetic field inhomogeneity worsens
Solution Approach 1:
The compensation coil is designed to generate a magnetic field with specific local characteristics that target only the frequency shift issue without introducing broad inhomogeneity. By carefully designing the coil geometry and positioning, the compensating field has the right local quality to correct frequency drift while minimizing negative effects on overall field homogeneity
3Stability of the object's composition
If temperature control of main magnet is improved, then magnetic field stability is improved, but device complexity and cost increase
Solution Approach 1:
The compensation coil serves as an intermediary that provides a simpler alternative to complex temperature control systems. Instead of using expensive and complex cryogenic or electronic temperature control to stabilize the main magnet, the system uses the compensation coil to actively correct magnetic field drifts through current adjustment, achieving similar stability with less complexity
Solution Approach 2:
The patent replaces the mechanical/thermal temperature control system with an electrical compensation system. Instead of physically controlling the main magnet's temperature through complex thermal management, the system uses electrical current in the compensation coil to generate magnetic field corrections, substituting a simpler electrical solution for a complex mechanical one
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 approach improves the stability and spectral resolution of NMR data acquisition by compensating for magnetic field inhomogeneities and temperature fluctuations, ensuring accurate frequency alignment and maintaining high signal quality across measurements.
Implementation Method 1
a main field magnet with main magnet poles for generating a main magnetic field (H0)
Implementation Method 2
at least one compensation coil... for compensating temporal changes of the main magnetic field
Implementation Method 3
a target channel for generating RF-pulses with a target excitation frequency and a lock data treatment system with a lock channel for generating RF-pulses with a lock excitation frequency
Data Source
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AI summary
An NMR spectrometer for carrying out the method according to any one of the preceding claims, the NMR spectrometer (1) comprising a compensation system (5) and a main field magnet (2) with main magnet poles (2a, 2b) for generating a main magnetic field (3), the compensation system (5) comprising: - at least one target sample coil (6) and a lock sample coil (7) positioned in a volume of interest (4), the volume of interest (4) being arranged between the main magnet poles (2a, 2b), - at least one compensation coil (8) for compensating a drift of the main magnetic field (3) within the volume of interest (4), - at least one target channel for generating RF-pulses with a target excitation frequency, and - a lock data treatment system (9) comprising a lock channel (12) for generating RF-pulses with a lock excitation frequency, wherein the lock data treatment system (9) is configured to adapt a compensation current in the at least one compensation coil (8) and to correct simultaneously the target frequency by applying a target frequency correction offset FCO at the target channel. The inventive NMR spectrometer has an improved lock channel, in particular for measurements where lock coil and the target coil are to be positioned at a separate position within the volume of interest, thus being placed in different magnetic field environments.