Paper | Title | Page |
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WEYO01 | The Einzel Lens Longitudinal Chopper | 95 |
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The Einzel lens longitudinal chopper [1] placed just after the ECRIS has been developed for the KEK digital accelerator [2] and is being operated without trouble over more than 1 year. Propagation of a msec-long ion pulse extracted with the ECRIS extraction voltage V1, is fully controlled by superimposing a rectangular-shape pulse voltage V2 (<0) on the fixed Einzel lens voltage V3 (V3 > V1). For most of time region (~msec), beam propagation is blocked, meanwhile for a time region (~5 μs), where V2 is on and V2 + V3 < V1, the beam can propagate downstream under the optimized transverse matching condition. Namely, the superimposed voltage V2 + V3 works as a gate voltage. This negative pulse voltage is produced by the solid-state switch driven Marx Generator, promising a fast rising/falling feature in the pulse profile. This chopper enjoys a lot of figure of merits originated from the fact that the beam can be handled at its minimum energy region:
[1] T. Adachi, K.W. Leo et al., "A Solid-state Marx Generator driven Einzel Lens Chopper", Rev. Sci. Inst. 82, 083305 (2011). [2] T.Iwashita et al., "KEK Digital Accelerator", Phys. Rev. ST-AB 14, 071301 (2011). |
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Slides WEYO01 [5.566 MB] | |