An improved Penning ion source has been developed. This ion source has two helical filaments at the two ends of the discharge chamber. The design of the filaments is such that the resultant magnetic field distribution, which is a combination of the external field and those due to the two filaments, focuses the electrons from the filaments to the plasma region near to the lateral extraction slit, thus creating a hollow cathode effect. This produces an efficient discharge and a good positive ion output. This ion source can produce various species of ions including the ions of reactive gases with a longer lifetime of filaments than for comparable sources.

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Vacuum arc ion sources are known for delivering high currents of ion beams in many technological applications. There is a great need in the present ion accelerator injection research for a titanium vacuum arc source to produce high-ionized plasma, in which its parameter is extremely important to match the extractors geometry and the extraction voltage. In this paper, the radial and angular distributions of the titanium cathodic vacuum arc plasma parameters are measured by a cylindrical Langmuir probe and analyzed by the Druyvesteyn method from the I-V curves. The electron density ne is about 10 17 m −3 and the effective electron temperature T eff is in the range of 6.12∼11.11 eV in the free expansion cup before the ion extraction. The measured distribution of ne over the expansion cross-section is non-uniform and axially unsymmetrical with its form similar to the Gaussian distribution, and most of the plasma is concentrated into an area whose radius is smaller than 5 mm. T eff has a nearly uniform distribution over the expansion cross-section during the discharge. The results of the plasma parameters' non-uniformity encourage the researchers to make some optimization designs to improve the parameter distributions, and then to facilitate ion extraction.

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