Patent attributes
Apparatus for determining magnetic properties of materials comprises a portable probe (1), an equipment trolley (2) holding cryogenics and electronics and connecting cables (3). The probe (1) comprises a drive coil (4) and a correction coil (5), the drive coil (4) being disposed symmetrically with respect to an inner second-order gradiometer sensor coil (8). Electrical connectors in the form of 2-meter long Belden (1192A) microphone cables (3) are used to connect the apparatus on the equipment trolley (2) to the drive coil (4), the correction coil (5) and the sensor coil (8). The drive coil (4) is driven so as to generate a sinusoidally varying magnetic field. The electronics comprise a flux-locked loop (9), a SQUID controller (10), a data acquisition module (11), which captures and processes the signals and a computer (12). A liquid-nitrogen dewar (13) is supported on the equipment trolley (2) and houses a sensitive SQUID detector (14) and a transfer coil (15) made from copper. Possible applications of the apparatus include an intra-operative tool for sentinel lymph node detection in the treatment of breast cancer, and a non-destructive evaluation tool for detecting voids and defects in aluminum and applications in the aeronautics industry.
