ARRANGEMENT AND METHOD FOR DETECTING AND/OR LOCATING A MAGNETIC MATERIAL IN A REGION OF ACTION, USE OF AN ARRANGEMENT IN THE EXAMINATION OF BUILDINGS

摘要

An arrangement and a method for detecting and/or locating magnetic material, and the use of an arrangement in the examination of buildings is disclosed, which arrangement comprises: selection means for generating a magnetic selection field having a pattern in space of its magnetic field strength such that a first sub-zone having a low magnetic field strength and a second sub-zone having a higher magnetic field strength are formed in the region of action, drive means for changing the position in space of the two sub-zones in the region of action by means of a magnetic drive field so that the magnetization of the magnetic material changes locally, receiving means for acquiring detection signals, which detection signals depend on the magnetization in the region of action, which magnetization is influenced by the change in the position in space of the first and second sub-zone, wherein the magnetic selection field comprises at least a time-variable field component varying at a frequency of at least about 100 Hz.