Apparatus and method for magnetising security targets

摘要

In one aspect the purpose of the apparatus is to create a magnetic field suitable for the conditioning of security targets composed small spring steel strips with a long permalloy backing of the type normally used in library books. This apparatus includes a row of coils which are energized progressively along the row in a time overlapped sequence. This creates a magnetic field at any point above the coils which remains substantially parallel to the target whilst the field strength decays from a magnetically saturating value to below a strength at which it has significant influence on the condition of the steel strips.