Characteristics of the nitrogen ion beam produced in a plasma focus device

The characteristics of the nitrogen ion beam produced in a plasma focus device have been studied experimentally to apply the beam to material processing. In this application, the purity of the ion beam is very important. To clarify the mechanism of the production of impurity ions, two types of anode (rod type: type A, hollow type: type B) were used. In the experiment, a Mather type plasma focus device was used with a capacitor bank of 43.2 /spl mu/F. To produce nitrogen ions, the device was pre-filled with N/sub 2/ at 5.5 Pa. Ion species and their energy spectra were evaluated using a Thomson parabola spectrometer. With type B anode, we have obtained a nitrogen ion beam of 90.5%, whereas with type A anode the purity was 26.5% and copper ion was observed as impurity. Next, the device was prefilled with N/sub 2//H/sub 2/ mixture gas at 20/180 Pa. In this experiment, impurity ions were not produced and highly ionized nitrogen ions were produced.