Effect of the pulse repetition rate on the composition and ion charge-state distribution of pulsed vacuum arcs
- Russian Academy of Sciences, Tomsk (Russian Federation). High Current Electronics Inst.
- Lawrence Berkeley National Lab., CA (United States)
The plasma composition and ion charge-state distributions of pulsed vacuum arcs have been investigated for carbon, aluminum, silver, platinum, and tantalum cathodes using a time-of-flight (TOF) charge-to-mass spectrometer. With the exception of carbon, it was found that all results depend on the arc pulse repetition rate, a fact which, up to now, has not been reported in the literature. It is shown that adsorption of gas on the cathode between arc pulses leads to contamination of the metal plasma and to a reduction of metal ion charge states. These usually undesired effects can be avoided by operating at high arc pulse repetition rates of order 10 Hz or more. The results can be interpreted in terms of cathode spot type 1 (on contaminated cathode surfaces) and type 2 (on clean surfaces) which are well known from their different brightness and erosion behavior. The transition between the modes was found to be gradual. Fully ionized metal plasmas can be produced at vacuum arc cathode spots. They are used, for instance, in vacuum arc ion sources for ion implantation and ion injection into accelerators. Vacuum arc metal plasmas are also used for thin film deposition and the plasma synthesis of highly adhesive metal or compound films by metal plasma immersion ion implantation and deposition.
- Sponsoring Organization:
- Russian Foundation for Basic Research (Russian Federation); USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 616408
- Journal Information:
- IEEE Transactions on Plasma Science, Vol. 26, Issue 2; Other Information: PBD: Apr 1998
- Country of Publication:
- United States
- Language:
- English
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