Pulsed-Beam Atomic Magnetometer for Dynamic Field Measurement

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Solution Overview

Problem

Magnetometer systems face inaccuracies due to sensitivity to dynamics and system misalignments when measuring whole field scalar magnetic fields, particularly in dynamic environments, as they often rely on multiple single-axis or dual-axis vector systems.

Innovation Solution

A pulsed-beam atomic magnetometer system, such as a Synchronous Light-pulse Atomic Magnetometer (SLAM), uses a laser system with pump and probe lasers to generate optical beams that interact with alkali metal vapors, allowing for precise measurement of external magnetic fields through Faraday rotation, with multiple measurement zones for scalar and gradient detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple single-axis or dual-axis vector systems are used to measure whole field scalar magnetic fields, then measurement capability is improved, but sensitivity to dynamics and system misalignments increases causing inaccuracy

Engineering Contradiction:

Improvewhole field scalar measurement accuracyVSAvoidsensitivity to dynamics and misalignments

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces mechanical/vector-based magnetic field measurement systems with an optical pumping and detection system using alkali metal vapors and lasers. This substitution eliminates the mechanical alignment issues and dynamic sensitivity problems inherent in vector systems while maintaining scalar measurement capability through optical Faraday rotation detection

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement approach from vector component analysis to direct scalar measurement through optical rotation angle detection. By measuring the Faraday rotation angle directly, the system achieves accurate scalar magnetic field measurement without being sensitive to dynamic movements or misalignments that plague vector systems

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If conventional magnetometer systems are used in dynamic environments, then basic measurement function is maintained, but measurement accuracy deteriorates due to dynamics sensitivity

Engineering Contradiction:

Improveoperation in dynamic environmentsVSAvoidmagnetic field measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical sensing elements with optical pumping and detection using alkali metal vapors in a cell. This optical system has no moving parts and is inherently insensitive to dynamic environments, allowing accurate measurements while maintaining adaptability to various operational conditions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses alkali metal vapors enclosed in a sealed cell, creating an isolated measurement environment that is insensitive to external disturbances. This inert measurement environment protects the sensing mechanism from dynamic environmental factors while maintaining measurement accuracy

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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

The system provides high sensitivity and stability in measuring external magnetic fields, enabling accurate scalar amplitude and direction detection, as well as magnetic field gradients, even in dynamic conditions.

Implementation Method 1

a circularly-polarized optical pump beam is provided through a sensor cell to facilitate precession of an alkali metal vapor in response to an external magnetic field

Methodology Applied

Scientific EffectOptical pumping:

Implementation Method 2

a linearly-polarized optical probe beam is provided through the sensor cell to provide a detection beam corresponding to the linearly-polarized optical probe beam exiting the sensor cell

Methodology Applied

Scientific EffectFaraday rotation: Faraday Effect

Data Source

PatentEP3605130B1Pulsed-beam atomic magnetometer system

Publication Date: 2022.01.26 NORTHROP GRUMMAN SYSTEMS CORP

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AI summary

One example includes a magnetometer system that includes a sensor cell comprising alkali metal vapor and at least one measurement zone corresponding to a three-dimensional spatial region within the sensor cell. The system also includes a laser system configured to provide an optical pump beam through the sensor cell in a pulsed manner to facilitate precession of the alkali metal vapor in response to an external magnetic field and to provide an optical probe beam through the sensor cell in a pulsed manner based on a precession frequency of the alkali metal vapor. The system also includes a detection system configured to detect the precession of the alkali metal vapor in response to a detection beam corresponding to the optical probe beam exiting the sensor cell and to calculate an amplitude and direction of the external magnetic field based on the detected precession of the alkali metal vapor.