Patent ID: 7847267

Claim:
A method comprising the steps of: directing a primary election beam to propagate along an optical axis through a column; deflecting the primary electron beam away from the optical axis upstream of an inner lens detector and back to propagating along the optical axis downstream of the inner lens detector, so that the primary electron beam propagates around the inner lens detector, said upstream and downstream locations each defined with respect to a direction of a propagation of the primary electron beam; impinging the primary electron beam on an object, thereby producing both low-energy and high-energy electrons resulting from at least one of reflection and scattering of the primary electron beam from the object, each of the produced low-energy and high-energy electrons having an initial trajectory with respect to the object; detecting a first portion of the produced high-energy electrons by an in-lens detector; directing, by introducing a substantial electrostatic field, a trajectory of the produced low-energy electrons and a second portion of the produced high-energy electrons towards the inner lens detector, wherein the initial trajectory of the second portion of the produced high-energy electrons is substantially coincident with the optical axis; detecting the directed low-energy electrons and the second portion of high-energy electrons by the inner lens detector; and controlling a division of the low-energy and high-energy electrons between the in-lens detector and the inner lens detector by modifying the substantial electrostatic field and modifying a distance between the column and the object.