Simple structure holey-plate ion source

A high-efficiency, lightweight, and low-cost microwave ion source, created and sustained by evanescent waves emitted from a parallel-plate type source with a holey-plate has been studied. This source is called a holey-plate (HP) ion source. The microwaves at 2.45 GHz propagate inside the parallel-plate structure and then are converted into an evanescent mode through the use of a HP with 3-mm-diam holes. The plate dimensions are 100 mmx140 mm and are separated by 10 mm. In these experiments, the entire unit of the parallel plate is placed in a vacuum chamber. Dense plasma is produced only on the HP. A 78 mmx108 mm argon ion beam is extracted from the HP using a single grid with 3-mm-diam holes. The ion current densities are in excess of 1.2 mA/cm2 at an extraction voltage of 500 V