Temporal Development of Ion Beam Mean Charge State in PulsedVacuum Arc Ion Sources
Vacuum arc ion sources, commonly also known as "Mevva" ionsources, are used to generate intense pulsed metal ion beams. It is knownthat the mean charge state of the ion beam lies between 1 and 4,depending on cathode material, arc current, arc pulse duration, presenceor absence of magnetic field at the cathode, as well background gaspressure. A characteristic of the vacuum arc ion beam is a significantdecrease in ion charge state throughout the pulse. This decrease can beobserved up to a few milliseconds, until a "noisy" steady-state value isestablished. Since the extraction voltage is constant, a decrease in theion charge state has a proportional impact on the average ion beamenergy. This paper presents results of detailed investigations of theinfluence of arc parameters on the temporal development of the ion beammean charge state for a wide range of cathode materials. It is shown thatfor fixed pulse duration, the charge state decrease can be reduced bylower arc current, higher pulse repetition rate, and reduction of thedistance between cathode and extraction region. The latter effect may beassociated with charge exchange processes in the dischargeplasma.
- Research Organization:
- COLLABORATION - High Current ElectronicsInstitute, Tomsk
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 927395
- Report Number(s):
- LBNL-63770; RSINAK; R&D Project: Z2T196; TRN: US0803195
- Journal Information:
- Review of Scientific Instruments, Vol. 79; Related Information: Journal Publication Date: January 2008; ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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