Mirror monochromator for charged particle beam apparatus

An apparatus for producing a charged particle beam with reduced energy width from a charged particle beam with a range of energies, the apparatus comprising:

• an energy-dispersive device that bends the high-energy component of the charged particle beam at less of an angle in comparison to the bending angle of the low-energy component of the charged particle beam, such that the higher and lower energy charged particle beam components exit said energy-dispersive device at different angles of trajectory;
• a charged particle mirror configured to reflect the charged particle beam, wherein charged particles entering at an angle with respect to the normal to the reflection plane of said mirror exit the mirror symmetrically with respect to said normal and at the same angle;
• a plurality of charged particle lenses configured to converge all energy components exiting said energy-dispersive device at different angles of trajectory at the charged particle mirror reflection plane;
• and
• a movable knife-edge plate positioned between the energy-dispersive device and the charged particle mirror that removes all charged particles with energies higher and lower than a selected energy.