The Magnetocardiography System was developed in our institute for measuring the magnetic field of the human heart. It is installed in the Magnetically Shielded Room in order to suppress environmental magnetic field disturbances. It consists of 6 SQUID magnetometers: 4 measurement SQUIDs and 2 reference sensors which are located 10 cm and 20 cm above the measurement sensors, respectively. Each sensor consists of a YBCO step-edge rf magnetometer with a 3.5 mm diameter washer, coupled to a 10 mm × 10 mm SrTiO3 substrate resonator, and is flip-chip-coupled to a 18 mm diameter flux focuser. The resultant magnetometer field sensitivity of 20 – 30 fT/rt(Hz) at 77 K proved to be sufficient for recording adult and even fetal magnetocardiograms.
The Magnetocardiography System is regularly used for demonstration and teaching in cooperation with the student’s lab (JuLab) of Forschungszentrum Jülich.