Primary experiment on high current hollow cathode ion source

Hollow cathode ion source has many advantages such as long lifetime, high density due to the hollow cathode effect, so it is used widely in spacecraft, accelerator, gas switch and sputter. A high current cathode ion source is studied in our lab. The reaction gas is hydrogen. Its pressure is between 1 Pa and 10 Pa. The current could be changed from 40 A to 120 A and the arc voltage is about 90 V. The typical V-I characteristics are measured under different pressures. The photograph of discharge is taken by a CCD camera. It shows that the discharge is uniformity. And the temporal photographs of discharge are taken by an ICCD camera. They show that at the beginning the discharge focuses on a spot, then grow to a uniformity circle, and finally extinguish. The higher the pressure is, the better the stability and uniformity are. The micrographs of cathode electrode are taken by a microscope, which confirm the discharge is in the cavity of cathode.