Thermal Analysis of Wearable OPM-MEG Array System for Auditory Evoked Experiments

High temperature on the surface of the OPM-MEG array can introduce physiological noise in MEG measurement and over temperature will result in scald to the skin of the epicranium. In this paper, an experimentally verified temperature field model of the OPM-MEG array is developed. The main heat sources and heat transmission of the system are analyzed, and temperature field distribution is obtained in detail by using the finite element method (FEM). A more efficient thermal management scheme was proposed which used a water-cooling design to control the sensor array temperature and verify better signal to noise ratio in auditory evoked experiments. The temperature at the bottom of sensor array can be reduced by
$17.8^\circ \text{C}$
roughly with water temperature of
$15^\circ \text{C}$
which falls within the scope of an acceptable sensible temperature. In auditory evoked experiment, the Euclidean distance between cortex where the N1m component is located and MEG signal positioning result is calculated. The location error is reduced by
$9.5~\%$
(left) and
$66.9~\%$
(right) due to the temperature control by using water cooling system. The method in this paper provides a theoretical basis for the future multi-channel MEG system design in thermal management.