Electron beam equipment

An electron beam equipment comprising:

• an electron gun configured to emit primary electrons;
• an energy filter configured to pass electrons with predetermined energy;
• a stage configured to hold a sample;
• and
• an objective lens configured to irradiate the sample held on the stage with the primary electrons that have passed through the energy filter,
• wherein the energy filter includes a beam slit and a pair of a magnetic deflector and an electrostatic deflector that are superimposed with each other,
• wherein an electron lens is provided between the beam slit and the pair of the magnetic deflector and the electrostatic deflector, the electron lens being a round lens configured to converge primary electron beams onto the beam slit and to form an image of a virtual light source of the electron gun on the beam slit, and being arranged such that application of a voltage of negative 1 kV to each said electrostatic deflector causes a 50% reduction in an energy distribution of said primary electron beams, and
• wherein the pair of the magnetic deflector and the electrostatic deflector are configured for decelerating or moderating electrons.