High frequency rotary eddy current probe device

An eddy current crack detection device comprising:

• a rotary drive;
• a high frequency rotary eddy current probe coupled to said rotary drive, said high frequency rotary eddy current probe comprising:
• a probe tip housing having an interior, a perimeter housing wall, and a rotating axis;
• a differential sensing coil arrangement comprising a group of sensing coils located within said interior in a position such that the group is offset from said rotating axis and biased toward said perimeter housing wall;
• and
• a partial electromagnetic shield coupled to said probe tip housing and positioned such that said differential sensing coil arrangement is located between said partial electromagnetic shield and said rotating axis, wherein a cross section of said partial electromagnetic shield in a plane perpendicular to said rotating axis forms an arc that spans only a portion of said perimeter housing wall;
• and
• a rotary mount coupled to said rotary drive and to said high frequency rotary eddy current probe, said rotary mount being configured to stabilize said probe tip housing while said rotary drive rotates said high frequency rotary eddy current probe.

A high frequency rotary eddy current probe comprising:

• a probe tip housing having an interior, a perimeter housing wall, and a rotating axis;
• a differential sensing coils arrangement, of only two sensing coils, located within said interior in a position offset from said rotating axis;
• a reflection coil wound around said differential sensing coil arrangement, said reflection coil being positioned off-axis relative to said rotating axis;
• and
• a partial electromagnetic shield located within said interior and between said reflection coil and said perimeter housing wall of said probe tip housing, wherein a cross section of said partial electromagnetic shield in a plane perpendicular to said rotating axis spans at least a sector of said perimeter housing wall upon which said reflection coil would be projected, without completely surrounding said differential sensing coils arrangement.