Paper |
Title |
Other Keywords |
Page |
IT12 |
Use of Superimposed Alternating Currents in Quadrupoles to Measure Beam Position with Respect to their Magnetic Centre
|
electron, storage-ring, lattice, radiation |
38 |
|
- N. Marks
CLRC, Daresbury Laboratory, Warrington, UK
|
The positional stability of the electron beam in a modern
state-of-the-art synchrotron radiation source is critical, as
the many experimental users require consistency in the
position and dimensions of the incoming photon beams
which are incident on their experimental samples. At the
Daresbury Synchrotron Radiation Source (SRS),
inaccuracies in the measurements of the positions of both
beam position monitors and the lattice quadrupoles can be
overcome by measuring the position of the electron beam
with respect to the magnetic centres of the quadrupoles.
This was achieved by superimposing an alternating
('ripple') current on the direct current excitation of a
single lattice quadrupole and examining the resulting
beam oscillations at remote positions in the storage ring.
If the electron beam is then subjected to a local distortion
at the position of this quadrupole, the amplitude of the
beam oscillation induced by the superimposed current is
minimised (nominally zero) when the beam is at the
quadrupole's magnetic centre. This paper presents details
of the electrical circuit developed to inject an alternating
current into the coils of individual quadrupoles and gives
details of the results achieved to date.
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|
PS04 |
Influence of transverse beam dimensions on beam position monitor signals
|
pick-up, emittance, synchrotron, instrumentation |
106 |
|
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PS09 |
Beam Steering With Image Processing In The Cryring Injection Beamline
|
injection, ion, focusing, synchrotron |
118 |
|
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|
PT01 |
Closed-orbit correction using the new beam position monitor electronic of Elsa Bonn
|
closed-orbit, electron, resonance, alignment |
153 |
|
- J. Dietrich, I. Mohos, J. Keil
IKP, Forschungszentrum Jülich GmbH, Jülich, Germany
|
RF and digital electronics, developed at the
Forschungszentrum Jülich/IKP were integrated to form
the new beam position monitor (BPM) system at the
Electron Stretcher Accelerator (ELSA) of the University
of Bonn. With this system the preservation of the
polarization level during acceleration was currently
improved by a good correction of the closed-orbit. All
BPM offsets relative to the magnetic quadrupole centers
were determined by the method of beam-based alignment.
The optics functions measured by the BPM system are in
good agreement with theoretical predictions.
|
|
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|
PT05 |
First results on closed-loop tune control in the CERN-SPS
|
feedback, simulation, acceleration, controls |
165 |
|
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|
PT10 |
Emittance and dispersion measurements at TTF
|
emittance, dipole, linac, acceleration |
180 |
|
- M. Castellano, A. Cianchi, V.A. Verzilov
INFN-LNF, Laboratori Nazionali di Frascati dell'INFN, Frascati, Italy
|
It is well known that beam dispersion , along with the
Twiss parameters and emittance, contributes to the beam
spot size. So that, in general, anomalous dispersion is an
undesirable event and must be minimized by careful tuning
the machine. If not, when the spot size is used to infer
beam emittances, as it is the case of the "quadrupole
scan" method, basically employed at TTF, the unknown
dispersion can lead to overestimated values for the emittance.
This paper presents the first attempt to determine the
dispersion function at several points of the TTF Linac and
to separate its contribution to the local emittance measurement,
performed by means of the OTR imaging technique.
|
|
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PT14 |
Experience with stripline beam position monitors on the TESLA test facility LINAC
|
linac, alignment, lattice, beam-transport |
190 |
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