Researchers from the University of Wisconsin-Madison, including Mayand Dangi, Prateek Rajan Gupta, Joseph Kasti, Nivedan Vishwanath, Michael Zepp, David Smith, Benedikt Geiger, and Jennifer T. Choy, have developed a new atomic sensor for precise magnetic field measurements in the intermediate-to-high field regime. This innovation, detailed in their paper published in the journal Review of Scientific Instruments, presents a significant advancement in magnetometry technology.
The team introduced SASHMAG, a sensor designed to measure magnetic fields greater than 0.2 Tesla using Rubidium-87. This sensor operates in a unique magnetic field regime known as the hyperfine Paschen-Back regime, where the interactions between the nucleus and electrons in the atom decouple. SASHMAG employs a counter-propagating pump-probe configuration to detect isolated, Doppler-free Zeeman transitions, which are shifts in atomic energy levels due to the presence of a magnetic field.
To interpret the complex spectra generated in this regime, the researchers developed a comprehensive multilevel optical Bloch-equation model. This model accurately reproduces the measured spectra at sub-Doppler resolution and captures the state mixing and nonlinear saturation dynamics of the atoms. The model is consistent with analytical expectations for power broadening and thermal Doppler scaling, ensuring its reliability.
The researchers demonstrated the sensor’s capability by retrieving magnetic field measurements from 0.2 Tesla to 0.4 Tesla with a precision of ±0.0017 Tesla. This level of precision is crucial for various applications, including magnetic resonance imaging (MRI) and fusion reactors. The validated simulation model also lays the groundwork for generating synthetic training datasets, which could enable autonomous, machine learning-enhanced magnetometry in the future.
The practical applications of this research are significant for the energy sector. In fusion reactors, precise magnetic field measurements are essential for controlling and stabilizing the plasma, which is the key to achieving sustainable nuclear fusion. Additionally, improved magnetometry can enhance the performance and accuracy of MRI systems, which are vital for medical diagnostics and research. The development of SASHMAG represents a step forward in the field of magnetometry, offering new possibilities for precision measurements in high-field environments.
Source: Review of Scientific Instruments
This article is based on research available at arXiv.