Method and apparatus for determining concentration of magnetic substances in a non-magnetic substance using a SQUID

摘要

Method and apparatus for determining concentration of a trace of contaminant magnetic substances contained in a non-magnetic substance. A magnetic field (3) is applied to the non-magnetic substance (1) from outside a duct (2) through which the non-magnetic substance is advanced so that magnetic substances contained in the non-magnetic substance are magnetized. At a downstream in the duct, an intensity of magnetic field produced substantially only by the magnetized magnetic substance is detected by a magnetic sensor (8) having a superconducting quantum interference device (SQUID).