| Autor: |
G. Datzmann, Günther Dollinger, H. J. Körner, G. Hinderer |
| Rok vydání: |
1997 |
| Předmět: |
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| Zdroj: |
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 130:51-56 |
| ISSN: |
0168-583X |
| DOI: |
10.1016/s0168-583x(97)00178-x |
| Popis: |
At the Munich 15 MV tandem accelerator a new two-stage microprobe system is under construction. It will demagnify a beam spot by a factor 200 in both transversal directions for ions up to an energy of 200 MeV · q2A. The second stage of the system is a superconducting quadrupole doublet lens, with overlayed 2n-poles, n = 4, 6 and 8. The multipole components of this lens have been determined by a ray tracing program with a special treatment of the fringing fields. As a result of these calculations, the overall geometrical aberrations at the focal point are 180 nm horizontally and 280 nm vertically at full angular acceptance (image coordinates ±9 and ±20 mrad, respectively). A main part of the superconducting lens is a central ceramic tube which defines the exact positions of the poles. Superconducting NbTi foils are used to shape the field to the desired one. Superconducting current loops automatically serve for a suppression of all odd harmonic field components. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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Full Text from ScienceDirect