Generation of a static magnetic field-free line using two Maxwell coil pairs

In this paper, the generation of a magnetic field-free line (FFL) along a constant direction is investigated. It is shown that an FFL gradient field can be generated by two perpendicular Maxwell coil pairs. These coils can be used for imaging distributions of superparamagnetic nanoparticles with high sensitivity applying the magnetic particle imaging technique. To this end, the FFL has to be rapidly moved back and forth while either the object or the coil assembly rotates slowly. The field quality of the proposed coil setup is assessed by manufacturing a prototype and measuring the magnetic field using a Hall-effect sensor.