PURPOSE: To improve resolution for a defect or a flaw by arraying a plurality of detector coils on flat surface with a baseline between the centers thereof kept in parallel to the surface of a specimen or the axis thereof, and connecting the coils so as to keep opposite the direction current generated in magnetic field.
CONSTITUTION: This device is constituted of a refrigerant 1 to generate superconducting state, a cryostat 3 to hold a probe 2 and to store the refrigerant 1, a SQUID (superconducting quantium interference device) 4, a detector coil 5, a drive section 6 to drive the SQUID 4 and measure a signal, and a signal processing section 7. Also, the detector coil 5 is formed out of two coils 51 and 52. These first and second detector coils 52 having the same area are arranged on the same plane, and one end of the first coil 51 is connected to one end of the second coil 52, while the other end of the first coil 51 connected to one end of the SQUID. The other end of the second coil 52 is connected to the other end of the SQUID 4. According to this construction, current generated when the two coils 51 and 52 are in uniform magnetic field, is kept in a direction opposite to the SQUID 4.
KAYANE KAZUO
ODAWARA NARIKAZU
ATAKA TATSUAKI
