A conformal array of microfabricated optically-pumped first-order gradiometers for magnetoencephalography

N. V. Nardelli, A. R. Perry, S. P. Krzyzewski, S. A. Knappe
2020 EPJ Quantum Technology  
An array of 21 first-order gradiometers based on zero-field optically-pumped magnetometers is demonstrated for use in magnetoencephalography. Sensors are oriented radially with respect to the head and housed in a helmet with moveable holders which conform to the shape of a scalp. Our axial gradiometers have a baseline of 2 cm and reject laser and vibrational noise as well as common-mode environmental magnetic noise. The median sensitivity of the array is 15.4 fT/Hz1/2, measured in a human-sized
more » ... ed in a human-sized magnetic shield. All magnetometers are operated independently with negative feedback to maintain atoms at zero magnetic field. This yields higher signal linearity and operating range than open-loop operation and a measurement system that is less sensitive to systematic and ambient magnetic fields. All of the system electronics and lasers are compacted into one equipment rack which offers a favorable outlook for use in clinical settings.
doi:10.1140/epjqt/s40507-020-00086-4 fatcat:sdr4tccrgza2fjgniw5u6dmkfi