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Characterizing atomic magnetic gradiometers for fetal magnetocardiography
I A Sulai1, Z J DeLand2, M D Bulatowicz2
1Department of Physics & Astronomy, Bucknell University, Lewisburg, Pennsylvania 17837, USA.
The Review of Scientific Instruments
|September 2, 2019
Summary
We developed a novel atomic magnetic gradiometer, achieving high sensitivity without cryogenics. This advancement aids in detecting faint magnetic signals, like fetal magnetocardiography, amidst background noise.
Area of Science:
- Physics
- Biomedical Engineering
- Magnetometry
Background:
- Atomic magnetometers (AMs) offer high sensitivity without cryogenics, surpassing superconducting quantum interference devices.
- A key limitation of AMs is their configuration as gradiometers for enhanced spatial measurements.
- Gradiometers are crucial for detecting weak magnetic fields and suppressing environmental noise.
Purpose of the Study:
- To develop a spin-exchange relaxation free (SERF) vector atomic magnetic gradiometer.
- To characterize the gradiometer's performance, including sensitivity and common-mode rejection.
- To introduce a metric for evaluating gradiometer performance and optimizing measurement configurations.
Main Methods:
- Development of a SERF vector atomic magnetic gradiometer.
- Measurement of magnetic field sensitivity and common-mode rejection ratio (CMRR).
- Introduction and application of a background suppression figure of merit.
Main Results:
- Achieved a magnetic field sensitivity of 3 fT cm-1 Hz-1/2.
- Demonstrated a common-mode rejection ratio greater than 150 from DC to 100 Hz.
- Validated the utility of the background suppression figure of merit for optimal baseline setting.
Conclusions:
- The developed atomic magnetic gradiometer offers superior performance for detecting weak magnetic signals.
- The new figure of merit aids in assessing gradiometer effectiveness and optimizing measurements.
- This technology shows promise for applications like fetal magnetocardiography (fMCG) detection.
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