Atomic Magnetometer Signal Contrast via Orthogonal Field Compensation

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Solution Overview

Problem

Current methods for detecting material responses, such as eddy current imaging, face challenges in effectively isolating secondary magnetic fields from primary fields, leading to reduced signal sensitivity and contrast in non-destructive testing, especially in detecting defects in conductive and ferromagnetic samples.

Innovation Solution

The method involves providing an oscillating primary magnetic field to induce a secondary magnetic field in a sample and using an atomic magnetometer to detect this response, with compensatory magnetic fields and axis alignment to reduce the effect of primary and secondary field components orthogonal to the sample surface, enhancing amplitude and phase contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an oscillating primary magnetic field is provided to induce a secondary magnetic field in a sample, then material response can be detected, but the effect of primary field components on the atomic magnetometer reduces signal sensitivity and contrast

Engineering Contradiction:
Improvesignal sensitivityVSAvoidprimary field component effect
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and eliminates the harmful primary field component effect from the measurement system by introducing a compensatory magnetic field that specifically counteracts the primary field's influence on the atomic magnetometer, allowing only the secondary field (material response) to be detected

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A compensatory magnetic field is introduced as an intermediary element between the primary magnetic field source and the atomic magnetometer. This intermediary field cancels out the primary field's harmful effects while preserving the ability to detect the secondary field generated by the sample

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If compensatory magnetic field is provided to reduce primary field effect, then signal contrast is improved, but device complexity increases

Engineering Contradiction:
Improveamplitude and phase contrastVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The compensatory magnetic field source is designed to serve multiple functions: it compensates for primary field effects, maintains the atomic magnetometer's sensitivity to secondary fields, and can be adjusted to optimize measurement conditions for different sample types and defect configurations

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If insensitive axis is aligned with direction orthogonal to sample surface, then primary field effect is reduced, but measurement orientation is constrained

Engineering Contradiction:
Improveorthogonal field component effectVSAvoidmeasurement orientation flexibility
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent makes the measurement system dynamic by allowing the atomic magnetometer's sensitive axis to be electronically oriented relative to the compensatory field. The system can adapt its measurement orientation based on the sample geometry and defect location, rather than being fixed in a single configuration

Inventive Principle:
Principle #15Dynamics

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 significantly increases the amplitude and phase contrast of the detected signals, providing improved sensitivity and clarity for material defect imaging, particularly in paramagnetic and ferromagnetic samples, enabling quicker defect identification in non-destructive testing.

Implementation Method 1

providing an oscillating primary magnetic field to cause the sample to produce a secondary magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

detecting the secondary magnetic field with the atomic magnetometer

Methodology Applied
Scientific EffectAtomic resonance: Resonance

Data Source

PatentEP3811068B1Method and system for detecting a material response
Publication Date: 2024.09.25 NPL MANAGEMENT LTD
  • EP3811068B1 patent drawingFigure 1(a)
  • EP3811068B1 patent drawingFigure 1(b)
  • EP3811068B1 patent drawingFigure 1(c)

AI summary

Disclosed herein is a method of detecting a material response. The method includes providing an oscillating primary magnetic field to cause as ample to produce a secondary magnetic field. The method also includes reducing the effect on an atomic magnetometer of components of the primary and secondary magnetic fields in a direction substantially orthogonal to a surface of the sample. The method also includes detecting the secondary magnetic field with the atomic magnetometer to detect the material response.