Charged-particle energy analyzer

A charged-particle energy analyzer apparatus comprising:

• a first electically-conductive mesh with openings for passage of charged particles, the first mesh being arranged to receive the charged particles on a first side and pass the charged particles to a second side;
• a first electrode arranged such that a first cavity is formed between the second side of the first mesh and the first electrode;
• a second electrically-conductive mesh with openings for passage of the charged particles, the second mesh being arranged to receive the charged particles on a second side and pass the charged particles to a first side
• a second electrode arranged such that a second cavity is formed between the first side of the second mesh and the second electrode;
• a third electrically-conductive mesh with openings for passage of the charged particles, the third mesh being arranged to receive the charged particles on a first side and pass the charged particles to a second side;
• and
• a position-sensitive charged-particle detector arranged to receive the charged particles after the charged particles pass through the third mesh,
• wherein the first, second and third electrically-conductive meshes together form an annular central mesh.