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| IT01 |
The Future of Nuclear Physics in Europe and the Demands on Accelerators techniques
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- W.F. Henning
GSI, Gesellschaft für Schwerionenforschung, Darmstadt, Germany
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Future large-scale facilities for research are very much under discussion
in Europe. This results, of course, on the one hand from the discussions
in the science communities and their identification of new frontiers in
research; but it also reflects to a certain degree the trend to pool
resources among the countries towards what has been labeled the “European
Research Area”.
In the field of nuclear physics and/or its intersections with particle
physics, several such efforts have been under consideration or are
underway. This applies to the study of the subnuclear degrees of freedom
of the strong interaction system(s) as well as to the extremes of the
atomic nucleus as the many-body system of the strong force.
In this talk an attempt is made to summarize the present status and
future plans, with emphasis on the facility concepts and their demands on
accelerator technology and development
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| IT02 |
Overview of the Diagnostics Systems of SOLEIL and DIAMOND
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- J.-C. Denard, L. Cassinari
SOLEIL, Societé Synchrotron Soleil, Saint-Aubin, France
- M. Dykes, R. Smith
ASTec, Daresbury Laboratory, Daresbury, UK
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SOLEIL and DIAMOND are two third-generation light sources in construction
in France and in Great Britain respectively. SOLEIL is scheduled to
deliver its first photons to its users in 2006 and DIAMOND in 2007. This
talk will present the beam diagnostic systems of both projects with
emphasizing technological novelties and the instruments that are
essential to their performances: BPM system, profile monitors and
feedback systems.
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| IT03 |
Single Pass Optical Profile Monitoring
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10 |
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- R. Jung, G. Ferioli, S. Hutchins
CERN, Geneva, Switzerland
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Beam profiles are acquired in transfer lines to monitor extracted beams
and compute their emittance. Measurements performed on the first
revolutions of a ring will evaluate the matching of a chain of
accelerators. Depending on the particle type and energy, these
measurements are in general performed with screens, making either use of
Luminescence or OTR [Optical Transition Radiation], and the generated
beam images are acquired with detectors of various types: CCD, CMOS, CID,
TV Tubes or Multi-Anode Photo-Multipliers. The principles, advantages and
disadvantages of both families of screens will be discussed in relation
with the detectors used. A possible evaluation method for luminescent
screens and beam test results will be presented. Finally other optical
methods used will be mentioned for completeness.
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| IT04 |
Challenges for LHC and Demands on Beam Instrumentation
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- J. Wenninger
CERN, Geneva, Switzerland
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The LHC machine presently under construction at CERN will exceed existing
superconducting colliders by about one order of magnitude for luminosity
and beam energies for pp collisions. To achieve this performance the
bunch frequency is as large as 40 MHz and the range in beam intensity
covers 5·109 protons to 3·1014 protons with a normalised
beam emittance as small as 3 μmrad. This puts very stringent demands on the beam
instrumentation to be able to measure beam parameters like beam
positions, profiles, tunes, chromaticities, beam losses or luminosity.
The presentation will pick out interesting subjects of the LHC beam
instrumentation field. The examples will be chosen to cover new detection
principles or new numerical data treatments, which had to be developed
for the LHC as well as aspects of operational reliability for
instrumentation, which will be used for machine protection systems.
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| IT05 |
Single Shot Electron-Beam Bunch Length Measurements
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- G. Berden, G.M.H. Knippels, D. Oepts, A.F.G. van der Meer
FOM, Institute for Plasma Physics 'Rijnhuizen', Nieuwegein, The Netherlands
- S.P. Jamison, X. Yan, A.M. MacLeod, W.A. Gillespie
Abertay, University of Abertay Dundee, Dundee, UK
- J.L. Shen
CNU, Capital Normal University, Beijing, China
- I. Wilke
RPI, Rensselaer Polytechnic Institute, Troy, NY, USA
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It is recognised by the Instrumentation community that 4th generation
light sources (like TESLA, LCLS) are posing some of the most stringent
requirements on beam diagnostics. Among these, the single-shot
electro-optic measurement of the bunch length and shape in the
sub-picosecond domain is an ongoing development.
The electro-optic detection method makes use of the fact that the local
electric field of a highly relativistic electron bunch moving in a
straight line is almost entirely concentrated perpendicular to its
direction of motion. This electric field makes an electro-optic crystal
placed in the vicinity of the beam birefringent. The amount of
birefringence depends on the electric field and is probed by monitoring
the change of polarization of the wavelength components of a chirped,
synchronized Ti:sapphire laser pulse.
This talk will provide details of the experimental setup at the Free
Electron Laser for Infrared eXperiments (FELIX) in Nieuwegein, The
Netherlands, where single shot images have been obtained of 1.7 ps long
electron bunches (beam energy 46 MeV, charge per bunch 200 pC).
Furthermore, future upgrading possibilities will be discussed.
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| IT06 |
Short Bunch Beam Profiling
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- P. Krejcik
SLAC, Stanford Linear Accelerator, Stanford, CA, USA
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The complete longitunal profiling of short electron bunches is discussed
in the context of 4th generation light sources. The high peak current
required for the SASE lasing process is achieved by longitudinal
compression of the electron bunch. The lasing process also depends on of
the preservation of the transverse emittance along the bunch during
this manipulation in longitudinal phase space. Beam diagnostic
instrumentation needs to meet several challenges: The bunch length and
longitudinal profile should be measured on a single bunch to characterize
the instantaneous, peak current along the bunch. Secondly, the transverse
emittance and longitudinal energy spread should be measured for slices of
charge along the bunch. Several techniques for invasive and noninvasive
bunch profiling will be reviewed, using as examples recent measurements
from the SLAC Sub Picosecond Photon Source (SPPS) and the planned
diagnostics for the Linac Coherent Light Source (LCLS). These include
transverse RF deflecting cavities for temporal streaking of the electron
bunch, RF zero-phasing techniques for energy correlation measurements,
and electro-optic measurements of the wake-field profile of the bunch.
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| IT07 |
Digital Signal Processing in Beam Instrumentation: Latest Trends and Typical Applications
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- M.E. Angoletta
CERN, Geneva, Switzerland
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During the last decade digital signal processing has found its way into
the beam instrumentation arena, to become an essential part of several
beam diagnostic systems. In fact, the recent impressive hardware
performance improvement made it possible for functions once exclusively
accomplished by analogue methods, to be enhanced by the application of an
alternative digital approach. This is true to a point that the conversion
to digital processing has become inevitable. Factors that favour crossing
the border towards digital implementation are obviously speed as well as
precision, signal-to-noise ratio, dynamic range, stability of components
and configuration capability, together with the availability of powerful
and user-friendly development tools. Improvement in A/D conversion and
processing speed has allowed successfully developing digital feedback
loops and on-line diagnostics. The ascent of such digital techniques
generated a concurrent and parallel interest in digital signal processing
algorithms and in the use of the associated digital hardware components.
Current trends in beam diagnostics include using Digital Signal
Processors (DSPs), Field Programmable Gate Arrays (FPGAs), digital
receivers and fast digitizers. The talk reviews latest developments and
illustrates selected digital applications, relevant to the beam
diagnostic area.
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| IT08 |
Diagnostic Challenges at SNS
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- M.A. Plum
LANL, Los Alamos National Laboratory, Los Alamos, NM, USA
- T.J. Shea, S. Assadi
ORNL, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- L. Doolittle
LBNL, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- P. Cameron, R. Connolly
BNL, Brookhaven National Laboratory, Upton, NY, USA
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The Spallation Neutron Source now being built in Oak Ridge, Tennessee,
USA, accelerates an H- ion beam to 1000 MeV with an average power of 1.4
MW. The H- beam is then stripped to H+, compressed in a storage ring to a
pulse length of 695 ns, and then directed onto a mercury neutron
spallation target. Most of the acceleration is accomplished with
superconducting rf cavities. The presence of these cavities, the high
average beam power, and the large range of beam intensity in the storage
ring, provide unique challenges to the beam diagnostics systems. In this
talk we will discuss these challenges and some of our solutions,
including the laser profile monitor system, the residual gas ionization
profile monitors, and network attached devices. Measurements performed
using prototype instrumentation will also be presented.
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| IT09 |
Smith-Purcell Radiation in View of Particle Beam Diagnostics
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- G. Kube
DESY, Deutsches Elektronen-Synchrotron, Hamburg, Germany
- H. Backe, W. Lauth, H. Schöpe
IKP, Institut für Kernphysik, Mainz, Germany
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The development of the next generation high quality electron beams which
are necessary for future high luminosity linear colliders and short
wavelengths free electron lasers requires sensitive and non-destructive
beam diagnostic techniques. In this context Smith-Purcell radiation
which is generated when a charged particle beam passes close to the
surface of a periodic structure (diffraction grating) is under discussion
as a compact and inexpensive beam profile monitor.
In order to study the basic emission process of Smith-Purcell radiation
also in view of possible applications for particle beam diagnostics,
experimental studies were performed at the Mainz Microtron MAMI in the
visible spectral region with a microfocused 855 MeV electron beam. The
radiation was separated from background components, as diffracted
synchrotron radiation and transition radiation generated by electrons
scratching the grating surface, by exploiting their specific emission
characteristics. These are
- the narrow emission cone in the direction perpendicular to the
grating surface,
- the dispersion relation |n| λ = D (1 / β - cos θ)
with n the diffraction order, β the reduced electron
velocity, and θ the angle of observation, and
- the charcteristic intensity scaling as a function of the distance
between beam axis and grating surface.
Based on the experimental results the use of Smith-Purcell radiation as
a longitudinal and transversal beam profile monitor will be discussed.
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| IT10 |
Advanced Diagnostics of Lattice Parameters in Hadron Colliders
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- J.-P. Koutchouk
CERN, Geneva, Switzerland
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With a beam stored energy exceeding by several orders of magnitude the
quench level of the magnets and non-negligible non-linear field
components, the control of the beam dynamics and losses in LHC must be
very precise. This is a strong incentive to strengthen as much as
possible the potential of beam diagnostics. This paper reviews some of
the developments in various laboratories that appear to have a large
potential. They either allow for a much better access to classical beam
parameters or for the measurement of quantities formerly not accessible.
Examples are a fast measurement of the betatron tunes, the use of PLL for
reliable tune tracking and feedback, new methods or ideas to measure the
chromaticity with the potential of feedback systems and similarly for the
betatron coupling, the measurement of high-order non-linear fields and
resonances and the potential of AC dipole excitation. This list is bound
to be incomplete as the field is fortunately very dynamic.
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