A method for radial extraction of ions from a PIG source using an asymmetrical Wien filter

Abstract

Abstract The ion optical system (IOS) of an injector based on an arc multiply charged ion source working in the magnetic field has been computed. The system consists of a PIG-type source with a radial exit slit, an accel-decel electrode system and an electrostatic compensator (Wien filter) to compensate the deflecting action of the magnetic field. It is shown that the hyperbolic potential distribution between the filter plates provides the ion beam with minimal deflection from the axis of the IOS at the exit of the IOS. The filter plates must have different absolute values of potentials and also a strong geometrical asymmetry to the IOS axis. A computer simulation of ion trajectories in the IOS, constructed by the proposed method, has been carried out. It is shown that an IOS of this type provides extraction of ions in a wide band of the A / Z ratio ( A is the atomic mass, Z is the ion charge) and a magnetic field value on the axis of the system. The beam, strongly deflected from the axis in the accel-decel section of the IOS, has the next typical average displacement and angle (with the axis) at the end of the IOS: ±1 mm and ±1°, respectively.