Patent ID: 7394246

Claim:
Superconductive quantum interference device (SQUID) system for measuring magnetic susceptibility of a material, comprising: a magnetic-flux sourcing unit, comprising an excitation coil set and a pick-up coil set, wherein the excitation coil set supplies a varying magnetic flux on the material and the pick-up coil set surrounds the material inside and detects an induced magnetic flux from the material; a magnetic-field transfer route, coupled to the pick-up coil set for transferring the induced magnetic flux to a location; and a magnetic-flux reading unit, comprising at least a SQUID set at the location to sense the induced magnetic flux and an electronic circuit block to read the induced magnetic flux from the SQUID set, wherein the excitation coil set of the magnetic-flux sourcing unit includes multiple coils driven respectively by multiple functional generators at multiple specific operation frequencies to apply the varying magnetic flux on the material.