Electrostatic lens to focus an ion beam to uniform density

Patent · Tue Jan 11 04:00:00 EST 1977

OSTI ID:7221994

Johnson, C H

A focusing lens for an ion beam having a gaussian or similar density profile is described. The lens is constructed to provide an inner zero electrostatic field, and an outer electrostatic field such that ions entering this outer field are deflected by an amount that is a function of their distance from the edge of the inner field. The result is a beam that focuses to uniform density in a manner analogous to that of an optical ring lens. In one embodiment, a conically-shaped network of fine wires is enclosed within a cylindrical anode. The wire net together with the anode produces a voltage field that re-directs the outer particles of the beam while the axial particles pass undeflected through a zero field inside the wire net. The result is a focused beam having a uniform intensity over a given target area and at a given distance from the lens.

• Assignee: Energy Research and Development Administration
• Patent Number(s): US 4002912
• OSTI ID: 7221994
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430300* -- Particle Accelerators-- Auxiliaries & Components
BEAM PROFILES
BEAMS
DESIGN
ELECTRIC FIELDS
ELECTROSTATIC LENSES
FOCUSING
ION BEAMS
LENSES
OPTICAL SYSTEMS
WIRES