| Paper |
Title |
Other Keywords |
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| IT03 |
Beam Loss Monitors at the ESRF
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beam-losses, radiation, injection, synchrotron |
3 |
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- B. Joly, U. Weinrich, G.A. Naylor
ESRF, The European Synchrotron Radiation Facility, Grenoble, France
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The European Synchrotron radiation facility is a third
generation x-ray source providing x-rays on a continuous
basis. As a facility available to external users, the
monitoring of radiation caused by the loss of high-energy
stored beam is of great concern. A network of beam loss
monitors has been installed inside the storage ring tunnel
so as to detect and localize the slow loss of electrons
during a beam decay. This diagnostic tool allows
optimization of beam parameters and physical aperture
limits as well as giving useful information on the
machine to allow the lifetime to be optimized and
defects localized.
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| CT12 |
Preliminary Test of a Luminescence Profile Monitor in the CERN SPS
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proton, ion, photon, injection |
95 |
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- J. Camas, R.J. Colchester, G. Ferioli, R. Jung, J. Koopman
CERN, Geneva, Switzerland
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In order to satisfy the tight emittance requirements of
LHC, a non-intercepting beam profile monitor is needed
in the SPS to follow the beam emittance evolution during
the acceleration cycle from 26 to 450 GeV. Beyond 300
GeV, the synchrotron light monitor can be used. To cover
the energy range from injection at 26 GeV to 300 GeV, a
monitor based on the luminescence of gas injected in the
vacuum chamber has been tested and has given
interesting results. This monitor could also be used in
LHC, where the same problem arises. Design and results
are presented for the SPS monitor.
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| PS07 |
Trajectory Measurements in the DAΦNE Transfer Lines
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linac, pick-up, damping, injection |
115 |
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- A. Stella, C. Milardi, M. Serio
INFN-LNL, Laboratori Nazionali di Legnaro, Legnaro, Italy
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An improved beam position monitor system has been
installed in the Transfer Lines (TL) connecting the
DAΦNE Linac to the collider Main Rings through the
Damping Ring, to monitor the beam trajectory and optimize
the transmission efficiency.
Signals from stripline type beam position monitors are
stretched, sampled through Track & Hold circuits and
digitized to 12 bits. The sampling stage is triggered,
according to the timing of the desired beam, to measure
the amplitude of the signals induced on a BPM.
Hardware control, data collection and reconstruction of
the beam position along the Transfer Lines are performed
by the DAΦNE Control System on a VME standard local
processor.
Design issues, implementation and performance of the
system are presented.
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| PS10 |
Ionisation losses and wire scanner heating: evaluation, possible solutions, application to the LHC.
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electron, proton, lepton, ion |
120 |
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- C. Fischer
CERN, Geneva, Switzerland
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Harmful heating mechanisms, resulting in wire breakage,
limit the utilisation of wire scanner monitors to below
a given beam intensity. This threshold depends on the
accelerator design parameters. In lepton colliders, the
short beam bunches generate strong wake-fields inside the
vacuum pipe which are sensed by the wire and are the
predominant current limit. These effects can be minimised
by a smooth design of the monitor cross section and by
choosing a wire made of an insulating material.
A second source of energy deposition inside the wire,
also present in hadron machines, and even when the wire
material is insulating, results from collision and ionisation
of the wire material atoms by the incident beam particles.
Calculations are presented to evaluate the efficiency of
this process and a possible solution is suggested which
may reduce this limitation. An example is given for the
case of the LHC.
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| PS13 |
Analysis of the proton beam in the DESY transport lines by video readout
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emittance, proton, background, luminosity |
129 |
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- F. Solodovnik, T. Limberg, K. Wittenburg
IHEP, Institute for High Energy Physics, Protvino, Russia
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Injection efficiency, beam optic matching and
emittance preservation are very important parameters in
achieving a high luminosity in large proton
accelerators. We improved the analysing system of the
phosphor screen readout of the proton transport lines in
the accelerator chain of HERA with respect to the
parameters above. The screens are read out by simple
CCD video cameras. The signals are stored in local
frame grabbers. An analogue output of the stored image
is multiplexed and read-out by a fast PCI frame grabber
card in a PC. The beam orbit and the beam emittance
can be measured from each screen. A Visual Basic
program is used to displays the trajectory and the
envelope of the beam from a single transfer. The same
program helps to drive bumps to achieve a proper
steering through the line. The beam width can be
measured from selected screens to calculate the
emittance and other beam parameters including their
errors. The read out and analysing system will be
described and measurements will be shown.
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| PT03 |
Measuring beam intensity and lifetime in BESSY II
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storage-ring, synchrotron, injection, microtron |
159 |
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- R. Bakker, R. Georgen, P. Kuske, J. Kuszynski
BESSY, Berliner Speicherring-Gesellschaft für Synchrotronstrahlung mbH, Berlin, Germany
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The measurement of the intensity of the beam in the
transfer lines and the storage ring are based on current
transformers. The pulsed current in the transfer lines is
measured with passive Integrating Beam Current
Transformers (ICT). The bunch charge is transferred to a
DC-voltage and sampled with a multifunction I/O-board
of a PC. The beam current of the storage ring is measured
with a high precision Parametric Current Transformer
(PCT) and sampled by a high quality digital volt meter
(DVM). A stand alone PC is used for synchronisation,
real-time data acquisition and signal processing.
Current and lifetime data are updated every second and
send via CAN- bus to the BESSY II control system. All
PC programs are written in LabVIEW.
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| PT09 |
The closed-orbit measurement system for the CERN antiproton decelerator
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antiproton, closed-orbit, pick-up, shielding |
177 |
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- M. LeGras, L. Søby, D.J. Williams
CERN, Geneva, Switzerland
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The closed-orbit measurement system for the new
Antiproton Decelerator (AD) employs 59 electrostatic
pick-ups (PU). The intensity range from 2·1010 down to
107 particles poses challenging demands on the dynamic
range and noise of the head amplifier. A low noiseamplifier
has been developed, having an equivalent input
noise of 0.6nV/√(Hz), allowing beam positions to be
measured to ±0.5 mm with 5·106 particles. Two
different gains take care of the large dynamic range.
After amplification and multiplexing, the PU signals are
fed to a network analyser, where each measurement
point corresponds to one PU. The network analyser is
phase locked to the RF of the AD, thus acting as a
“tracking filter” instrument. An orbit measurement takes
from 0.2 to 12 s depending on the IF-bandwidth of the
network analyser, selected according to the beam
intensity, and the precision required. At the end of the
network analyser sweep the data are read via a GPIB
interface and treated by a real-time task running in a
VME based Power PC.
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| PT19 |
A method for measurement of transverse impedance distribution along storage ring
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impedance, pick-up, betatron, storage-ring |
202 |
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- V. Kiselev, V. Smaluk
BINP, Budker Institute of Nuclear Physics, Novosibirsk, Russia
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A new method for measurement of transverse couple
impedance distribution along storage ring is described.
The method is based on measuring of a closed orbit
deviation caused by local impedance. Transverse
impedance acts on the beam as a defocusing quadrupole,
strength of which depends on the beam current. If a local
bump of closed orbit has been created at the impedance
location, then the orbit deviation occurs while varying
the beam current. The local impedance can be evaluated
using the orbit deviation measured. Measurement
technique is described, the method accuracy is
evaluated. The method described was successfully used
for measurement of the impedance distribution along the
VEPP-4M storage ring.
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