For Magnetocardiography (MCG) applications in unshielded environment, our Axial HTS rf SQUID Gradiometer System is especially well suited. The gradiometer consists of two SQUID magnetometers, each with a sensitivity better than 30 fT/root(Hz) at 77 K (in shielding in the white noise regime, > 30 Hz). The gradiometer baseline is adjustable from 6 cm to 10 cm. The system uses our novel substrate resonators as tank circuits. The liquid nitrogen dewar holds for approximately 5 days (inside volume 5 l). The system is portable. The SQUID readout electronics is automated, the working points are adjusted by the integrated microcontroller.
