Investigation and treatment of a cylindrical saddle field ion source

An analysis for a modified cylindrical saddle field ion source has been carried out. The ion source consists of two copper anode rods surrounded by a stainless steel cylindrical cathode. In the actual design of the cylindrical saddle field ion source, the diameter of the stainless steel cathode cylinder is equal to 30 mm with length equals 55 mm. The potential distribution and the electric field are calculated in the radial direction at the mid plane of the ion source. In these distributions, the effect of the separation distance between the two axially anode rods are taken into consideration. The electric field distribution shows a maximum whose value increases and its radial position decreases by decreasing the separation distance. The variation of the radial and axial field with radial distance in a plane perpendicular to the cylindrical axis have been determined for axial distances 0.5 mm, 1 mm and 1.5 mm and for anode separation distance 5 mm. The investigation of such variation show that the field has a saddle shape near the central region between the two anode rods and consequently high-density discharge can be achieved