| Paper |
Title |
Other Keywords |
Page |
| CT02 |
Determination of Radial Ion Beam Profile from the Energy Spectrum of Residual Gas Ions Accelerated in the Beam Potential
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ion, electron, emittance, acceleration |
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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| PS11 |
Ionisation profile monitor tests in the SPS
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electron, ion, proton, insertion |
123 |
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- C. Fischer, J. Koopman
CERN, Geneva, Switzerland
| |
A beam profile monitor, from DESY, based on the ionisation
of the rest gas, was installed in the SPS in 1997. Horizontal
beam profiles obtained from the extracted positive ions are
presented. It is known that in this case some broadening affects
the signal, which limits the monitor resolution. This broadening
results from the transverse momentum that the ions gain
within the space charge field of the circulating beam.
In order to improve the resolution for LHC applications, the
monitor was modified during the 1998/99 winter stop. A magnetic
focusing was incorporated. The aim is to analyse the signal
provided by collecting the electrons, rather than the ions,
of the ionised rest gas. The details of this new set-up and the
expectations for the resolution limit will be compared to the
measurement results.
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