Applications of the Ultralow Magnetic Field Facility

Overview

The Magnetically Shielded Room (MSR) serves as a reference environment for experiments that require extremely low magnetic noise and high field stability.
It provides an ideal platform for studies in biomagnetism, quantum sensing, and spin-precession physics, combining passive shielding, active stabilization, and precision motion control.

A key feature of the facility is a fully non-magnetic 3D field-mapping system, which allows automated, high-precision positioning of sensors or test samples inside the shielded volume.
This enables spatially resolved field characterization and systematic studies of magnetic homogeneity, gradients, and residual field drifts — critical for both biomagnetic and fundamental physics applications.

Biomagnetic Measurements

The MSR offers the ultralow-field conditions required for detecting weak biological magnetic fields in the pico- to femtotesla range.
This includes:

• magnetocardiography (MCG) and fetal MCG (fMCG),
• and studies of neuromagnetic or muscle activity using optically pumped magnetometers.

The combination of passive shielding and active field stabilization allows the recording of biomagnetic signals with exceptional clarity and reproducibility.
Furthermore, the facility serves as a test and calibration site for portable OPM-based systems such as the HeartShield, bridging high-precision laboratory instrumentation and clinical applications.

Spin-Precession and Spin Clock Experiments

The MSR’s residual field below the nanotesla level and sub-pT/h stability make it a unique environment for spin-precession and co-magnetometer experiments.
Here, long spin-coherence times are achieved for noble-gas or atomic ensembles, enabling:

• studies of fundamental symmetries (e.g. EDM and Lorentz-violation searches),
• development of ultrastable spin clocks, and
• precise frequency and phase-stability tests.

The combination of active field control and 3D field mapping allows detailed correlation of spin-dynamics data with the spatial field environment, supporting both experimental optimization and simulation validation.

Magnetometer Development and Calibration

The facility provides a noise-free environment for the development and characterization of high-sensitivity magnetometers, including:

• optically pumped cesium and sodium sensors,
• fluxgate and gradiometric probes, and
• custom sensor arrays for field imaging or feedback applications.

The integrated 3D field-mapping system enables systematic sensor calibration by positioning the devices along predefined trajectories and recording the magnetic response throughout the room.
This allows precise evaluation of:

• sensitivity,
• drift stability,
• angular dependence, and
• cross-talk behavior under well-controlled field conditions.

Such measurements provide benchmark data for both in-house sensor development and external collaborations in quantum sensing and precision measurement.

Publications and finished Theses

Involved Persons and Former Members

Currently Involved persons: Dr. Florian Kuchler, Maximilian Huber, Lena Wunderl, Philipp Wunderl

Former Members: