Low-noise superconducting quantum interference devices for measuring brain and cardiac magnetic signals

As sensitive magnetic sensors, superconducting quantum interference devices (SQUIDs) can be applied to measure weak magnetic field signals. Biomagnetism, measurement of magnetic signals from human body, especially at low frequency range below few kHz, is one of the important applications of SQUIDs, and biomagnetic technology can be applied for the functional study of human brain and heart. KRISS has been developing both low-noise SQUIDs and biomagnetic measurement technology. The SQUIDs are low-temperature Nb double relaxation oscillation SQUID, and high-temperature YBCO SQUID. We are applying SQUID technology for measuring magnetoencephalography signals and magnetocardiography signals. Using the high sensitivity of SQUID, we are developing nuclear magnetic resonance technology for imaging of brain anatomy at very low magnetic field, and direct imaging of brain electrical activity.