Arrangement with magnetic field sensor esp. SQUID or Forster probe for eddy current testing

摘要

The magnetic field sensor has a coil configuration, with the respective centres of the coils are arranged lying on a circle. The circle centre, the magnetic field sensor and the sample under test, form a vertical line (sensor axis) to the coil plane. The coil arrangement consists of several individual coils, which are electronically so coupled, that the coil system at the sample place, produces a rotational field, such that it has a min. in the direction of the sensor axis. A SQUID magnetometer or a SQUID gradiometer is used as the magnetic field sensor. The coils can be arranged in pairs opposite to each other. A coil configuration can have a modulator rotating field, a continuous rotating field or an amplitude modulated rotating field.