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| CT02 |
Determination of Radial Ion Beam Profile from the Energy Spectrum of Residual Gas Ions Accelerated in the Beam Potential
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50 |
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- R. Dölling
IAP, Institut für angewandte Physik der Johann Wolfgang Goethe Universität
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Residual gas ions (RGI) created from collisions of
positive beam ions (BI) with residual gas atoms are
accelerated out of the ion beam by its space charge
potential. It is demonstrated that with one-dimensional
radial symmetry the radial distributions of BI density and
space charge potential can be determined from the energy
distribution of RGI radially leaving the beam tube. RGI
energy spectra were taken with an electrostatic analyser of
Hughes-Rojansky type on a 10 keV 1.5 mA He+ beam.
For comparison the radial BI density distribution was
determined with a radial wire probe, an electron beam
probe and a beam transport calculation based on an
emittance measurement located downstream.
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