Abstract:Plasma windows with a high vacuum tightness and a good beam throughput have promising applications in electron beam welding, accelerators and so on. This paper, aiming at the small-size problems of traditional plasma window apertures, presents the sealing characteristics of the plasma windows with channel diameters of 7 mm and 8 mm on the basis of the optimized three cathode sources. The relationship between the pressure drop coefficient(PDC) of Ar, He and H2 and such experimental parameters as the input current and gas flow rate is studied, respectively. The input current was ranged from 120 to 210 A and the gas flow rate was done from 1000 to 5000 sccm. The results show that the PDC of the Ar plasma window firstly increases and then decreases with the increases of both the input current and gas flow rate. Differently, the PDC of the He and H2 plasma windows gradually increases with the increase of the input current,and with the increase of gas flow rate, the PDC of the He plasma window firstly increases and then decreases and the PDC of the H2 plasma window gradually decreases. The maximum PDC of the plasma windows obtained in this work is 2550, and the isolatable maximum high pressure is 1 atm. Compared with the reported literatures, these data mean that the developed plasma windows have a good competitive advantage and shows a good sealing performance for potential applications in fields of future accelerators.
