A deflection system is presented for use in a lens arrangement of a charged particle beam column for inspecting a sample. The system comprises a magnetic deflector operable to create a magnetic field, and a pole piece assembly at least partly accommodated within the magnetic field. The pole piece assembly has a portion made of a soft magnetic material and is formed with an opening for a charged particle beam propagation therethrough. The deflection system allows for conducting the magnetic field created by the magnetic deflector through the pole piece assembly towards the opening in the pole piece assembly. This enables to increase the magnetic field value in the vicinity of the sample at the optical axis of the lens arrangement at a given electric current through the excitation coils of the magnetic deflector, without a need to increase a working distance.