Speaker
Description
It is reported from the measurement of a negative ion beamlet emittance that the characteristic three-Gaussian components are observed in the emittance diagram. These components can be identified as a combination of three beam components with different beam axes. In order to clarify the origin of this complicated phase space structure and underlying physical mechanism, potential structure and particle dynamics including the negative ion trajectories have been calculated in a 3D (three-dimensional) model geometry.
The region from the source plasma up to the accelerator is modeled for a single aperture, and thus, the plasma meniscus can be obtained self-consistently. The characteristic three-Gaussian components can be reproduced in the emittance diagram from the simulation result. It is shown that the Gaussian components are caused by the negative ions extracted from the different plasma meniscus region, that is, the central region or the region near the edges of the meniscus.
| E-mail for contact person | kmiyamot@naruto-u.ac.jp |
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