Paper |
Title |
Page |
CT07 |
Excitation of Large Transverse Beam Oscillations without Emittance Blow-Up Using the "AC-Dipole" Principle
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82 |
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- O. Berrig, W. Höfle, R. Jones, J. Koopman, J.-P. Koutchouk, F. Schmidt
CERN, Geneva, Switzerland
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The so-called "AC-Dipole" principle allows the excitation of transverse
oscillations to large (several σ) excursions without emittance
blow-up. The idea was originally proposed and tested at BNL for
resonance crossing with polarized beams, using an orbit corrector dipole
with an excitation frequency close to the betatron tune, hence
"AC-Dipole". This method of beam excitation has several potential
applications in the LHC, such as phase advance and β-measurements,
dynamic aperture studies and the investigation of resonance strengths.
The technique was recently tested in the CERN-SPS using the transverse
damper as an "AC-Dipole" providing the fixed frequency excitation.
results from this experiment are presented, along with an explanation of
the underlying principle.
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PM15 |
Sensitivity Studies with the SPS Rest Gas Profile Monitor
|
201 |
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- G. Ferioli, C. Fischer, J. Koopman, M. Sillanoli
CERN, Geneva, Switzerland
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During the SPS run in the year 2000 further test
measurements were performed with the rest gas monitor.
First, profiles of single circulating proton bunches were
measured and the bunch charge progressively reduced, in
order to determine the smallest bunch intensity which can
be scanned under the present operating conditions. The
image detector in this case was a CMOS camera.
Using a multi-anode strip photo-multiplier with fast
read-out electronics, the possibility to record profiles on a
single beam passage and on consecutive turns was also
investigated. This paper presents the results of these tests
and discusses the expected improvements for the
operation in 2001.
Moreover, the issue of micro channel plate ageing
effects was tackled and a calibration system based on
electron emission from a heating wire is proposed. The
gained experience will be used for the specification of a
new monitor with optimised design, to be operated both in
the SPS and in the LHC.
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