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ABSTRACT: The International Linear Collider (ILC) utilizes a two stage bunch compressor (BC) that compresses the RMS bunch length from 9 mm to 200 to 300 micrometers before sending the electron beam to the Main Linac. This paper reports on the new design of the optimized BC wiggler. It was reduced in length by more than 30%. The introduction of nonzero dispersion slope in the BC wigglers enabled them to generate the required compression while having a small synchrotron radiation emittance growth, a tunability range of over a factor of 2 in each wiggler, and less than 3% RMS energy spread throughout the entire system.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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A. Seryi,
J. Amann,
R. Arnold,
F. Asiri,
K. Bane,
P. Bellomo,
E. Doyle,
A. Fasso,
K. Jonghoon,
L. Keller, [......],
T. Mattison,
J. Carwardine,
C. Saunders,
R. Appleby,
E. Torrence,
J. Gronberg,
T. Sanuki,
Y. Iwashita,
V. Telnov,
D. Warner
[show abstract]
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ABSTRACT: The beam delivery system for the linear collider focuses beams to nanometer sizes at its interaction point, collimates the beam halo to provide acceptable background in the detector and has a provision for state-of-the art beam instrumentation in order to reach the ILC's physics goals. This paper describes the design details and status of the baseline configuration considered for the reference design and also lists alternatives.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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M Woods,
R Erickson,
J Frisch,
C Hast,
R.K. Jobe,
L Keller,
T. Markiewicz,
T Maruyama,
D. McCormick,
J Nelson, [......],
M Thomson,
D Ward,
S Boogert,
A. Liapine,
S. Malton,
D J Miller,
M. Wing,
R Arnold,
N Sinev,
E Torrence
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ABSTRACT: The SLAC Linac can deliver damped bunches with ILC parameters for bunch charge and bunch length to End Station A. A 10Hz beam at 28.5 GeV energy can be delivered there, parasitic with PEP-II operation. We plan to use this facility to test prototype components of the Beam Delivery System and Interaction Region. We discuss our plans for this ILC Test Facility and preparations for carrying out experiments related to collimator wakefields and energy spectrometers. We also plan an interaction region mockup to investigate effects from backgrounds and beam-induced electromagnetic interference.
06/2005;
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S. Araki,
H. Hayano,
Y. Higashi,
Y. Honda,
K. Kanazawa,
K. Kubo,
T. Kume,
M. Kuriki,
S. Kuroda,
M. Masuzawa, [......],
A. Seryi,
C. Spencer, P. Tenenbaum,
M. Woodley,
S. Boogert,
A. Liapine,
S. Malton,
E. Torrence,
T. Sanuki,
T. Suehara
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ABSTRACT: To reach design luminosity, the International Linear Collider (ILC) must be able to create and reliably maintain nanometer size beams. The ATF damping ring is the unique facility where ILC emittances are possible. In this paper we present and evaluate the proposal to create a final focus facility at the ATF which, using compact final focus optics and an ILC-like bunch train, would be capable of achieving 37 nm beam size. Such a facility would enable the development of beam diagnostics and tuning methods, as well as the training of young accelerator physicists.
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
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M. Woods,
R. Erickson,
J. Frisch,
C. Hast,
R.K. Jobe,
L. Keller,
T. Markiewicz,
T. Maruyama,
D. McCormick,
J. Nelson, [......],
M. Thomson,
D. Ward,
S. Boogert,
A. Liapine,
S. Malton,
D.J. Miller,
M. Wing,
R. Arnold,
N. Sinev,
E. Torrence
[show abstract]
[hide abstract]
ABSTRACT: The SLAC Linac can deliver damped bunches with ILC parameters for bunch charge and bunch length to End Station A. A 10Hz beam at 28.5 GeV energy can be delivered there, parasitic with PEP-II operation. We plan to use this facility to test prototype components of the Beam Delivery System and Interaction Region. We discuss our plans for this ILC Test Facility and preparations for carrying out experiments related to collimator wakefields and energy spectrometers. We also plan an interaction region mockup to investigate effects from backgrounds and beam-induced electromagnetic interference.
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
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ABSTRACT: The main linac of the International Linear Collider (ILC) requires more sophisticated alignment techniques than those provided by survey alone. Various Beam-Based Alignment (BBA) algorithms have been proposed to achieve the desired low emittance preservation. Dispersion Free Steering, Ballistic Alignment and the Kubo method are compared. Alignment algorithms are also tested in the presence of an Earth-like stray field.
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
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ABSTRACT: We present bunch compressor designs for the International Linear Collider (ILC) which achieve a reduction in RMS bunch length from 6 mm to 0.3 mm via multiple stages of compression, with stages of acceleration inserted between the stages of compression. The key advantage of multi-stage compression is that the maximum RMS energy spread is reduced to approximately 1%, compared to over 3% for a single-stage design. Analytic and simulation studies of the multi-stage bunch compressors are presented, along with performance comparisons to a single-stage system. Parameters for extending the systems to a larger total compression factor are discussed.
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
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J. Seeman,
M. Browne,
Y. Cai,
W. Colocho,
F.-J. Decker,
M. Donald,
S. Ecklund,
R. Erickson,
A. Fisher,
J. Fox, [......],
D. van Winkle,
U. Wienands,
M. Woodley,
Y. Yan,
G. Yocky,
W. Kozanecki,
G. Wormser,
M. Biagini,
C. Steier,
A. Wolski
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ABSTRACT: PEP-II is an e<sup>+</sup>e<sup>-</sup>asymmetric B-Factory Collider located at SLAC operating at the Upsilon 4S resonance (3.1 GeV x 9 GeV). It has reached a luminosity of 9.21×10<sup>33</sup>/cm<sup>2</sup>/s and has delivered an integrated luminosity of 710 pb<sup>-1</sup>in one day. PEP-II has delivered, over the past six years, an integrated luminosity to the BaBar detector of over 262 fb-1. PEP-II operates in continuous injection mode for both beams boosting the integrated luminosity. The peak positron current has reached 2.45 A in 1588 bunches. Steady progress is being made in reaching higher luminosity. The goal over the next several years is to reach a luminosity of 2.1x10<sup>34</sup>/cm<sup>2</sup>/s. The accelerator physics issues being addressed in PEP-II to reach this goal include the electron cloud instability, beam-beam effects, parasitic beam-beam effects, high RF beam loading, shorter bunches, lower y interaction region operation, and coupling control. Figure 1 shows the PEP-II tunnel.
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
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ABSTRACT: To fully characterize the luminosity performance of a linear collider, it is important to simulate the effects of ground motion as well as the beam-beam feedback and other stabilization systems planned to compensate for that motion. The linear collider simulation codes have recently been extended to include both ground motion models and stabilization systems to support the work of the International Linear Collider Technical Review Committee (TRC). This paper discusses the implementation details and the optimization strategies for interpulse beam-beam feedback.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
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A. Drozhdin,
G. Blair,
L. Keller,
W. Kozanecki,
T. Markiewicz,
T. Maruyama,
N. Mokhov,
O. Napoly,
T. Raubenheimer,
D. Schulte,
A. Seryi, P. Tenenbaum,
N. Walker,
M. Woodley,
F. Zimmermann
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ABSTRACT: This report describes studies performed in the framework of the Collimation Task Force organized to support the work of the second International Linear Collider Technical Review Committee. The post-linac beam-collimation systems in the TESLA, JLC/NLC and CLIC linear-collider designs are compared using the same computer code under the same assumptions. Their performance is quantified in terms of beam-halo and synchrotron-radiation collimation efficiency. The performance of the current designs varies across projects, and does not always meet the original design goals. But these comparisons suggest that achieving the required performance in a future linear collider is feasible.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
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ABSTRACT: The performance of high energy linear colliders depends critically on the stability with which they can maintain the collisions of nanometer-size beams. Ground motion and vibration, among other effects, will produce dynamic misalignments which can offset the beams at the collision point. A system of train-to-train and intra-train beam-beam feedbacks, possibly combined with additional beam-independent active systems, is planned to compensate for these effects. Extensive simulation studies of ground motion and luminosity stabilization have been performed as part of the work of the International Linear Collider Technical Review Committee. This paper presents a comparison of the expected performance for TESLA, JLC/NLC and CLIC under various assumptions about feedbacks and the level of ground motion.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
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P. Tenenbaum
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ABSTRACT: The Standard Input Format for the description of accelerator
beamlines has achieved limited acceptance due to the complexity of the
parser required. We describe a standalone library of Fortran-90 routines
which can be used to parse a superset of the Standard Input format in
use at SLAC, named Extended Standard Input Format (XSIF). This library
provides authors of new simulation codes with a simple means of adding
XSIF compatibility to their programs, and also permits users to add
their own features to the parser with relative ease. As examples we
describe the manner in which the linear accelerator code LIAR was
modified to use LIBXSIF, and changes made to DIMAD to switch from its
internal Standard Input Format parser to use of the external XSIF
parser. URLs for the source code, documentation, and ready-to-use
libraries are provided
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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P. Tenenbaum,
K. Bane,
L. Eriksson,
R.K. Jobe,
D. McCormick,
C.K. Ng,
T.O. Taubenheimer,
M.C. Ross,
G. Stupakov,
D. Walz,
D. Onoprienko
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ABSTRACT: We report on a series of measurements of the transverse wakefield
from tapered collimators. The collimators were designed to principally
present a geometric impedance to the beam, and to minimize impedances
from resistivity or surface features; in addition, the geometries of the
collimators were selected to permit examination of the scaling behavior
of the wakefield due to collimator taper angle and minimum gap size. We
present the measured near-center wakefields of the collimators, as well
as the effect of bunch-length variation. The measurements are compared
to analytic models and MAFIA simulations
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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ABSTRACT: The performance of future linear colliders are limited by the
effect of short-range collimator wakefields on the beam. The beam
quality is sensitive to the positioning of collimators at the end of the
linac. The determination of collimator wakefields has been difficult,
largely because of the scarcity of measurement data, and of the
limitation of applicability of analytical results to realistic
structures. In this paper, numerical methods using codes such as MAFIA
are used to determine a series of tapered collimators with rectangular
apertures that have been built for studies at SLAC. We study the
dependences of the wakefield on the collimator taper angle, the
collimator gap as well as the bunch length. Calculations are also
compared with measurements
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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ABSTRACT: The performance of the new NLC Final Focus system has been
investigated as a function of the incoming beam characteristics, such as
energy, emittances, energy spread. A preliminary study of the tolerances
and the tunability of the system is presented in this paper
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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[show abstract]
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ABSTRACT: Focusing in the NLC main linac will be provided mainly by hybrid
permanent magnet quadrupoles which have limited variability in strength.
When the energy profile of the linac changes, due to normal cycling of
RF sources, mismatches in the beam optics can be generated if the
quadrupole strengths are not rescaled to the new energy profile. These
mismatches can lead to emittance dilution. In addition, betatron phase
advance changes caused by the mismatch can adversely affect the beam
trajectory, leading to emittance dilution from dispersion and
wakefields. This paper describes the results of simulations of these
processes, undertaken in an attempt to determine whether or not
rescaling of the quadrupoles will be necessary in the NLC main linac
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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ABSTRACT: One of the factors that limited the performance of the Stanford
Linear Collider (SLC) was the number of particles per bunch with large
betatron or energy amplitudes. We consider the equivalent problem for
the Next Linear Collider (NLC) main X-band linacs. We evaluate the
number of large-amplitude particles which can be expected due to
scattering processes, wakefields, and magnet nonlinearities. We conclude
that the number of particles in the beam halo from these sources can
easily be accomodated by the planned post-linac collimation system
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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ABSTRACT: The Next Linear Collider (NLC) requires a substantial system of
beam collimators to minimize the halo-related backgrounds at the
interaction point, provide machine protection against errant pulses, and
limit radiation doses throughout the accelerator. In particular, the NLC
design contains a complete 5-dimensional (x,x',y,y',energy) collimation
system at the entrance and exit of the main linac; transverse
collimators at the electron and positron sources, at the 250 MeV point
in the injector linac, and immediately upstream of the damping rings; a
series of collimators at points with substantial z-energy correlation
for longitudinal collimation; and a final set of transverse and energy
collimators in the final focus, a few hundred meters from the IP. We
describe the systems above and estimate the intensity of the halo at
each point, as well as the efficiency with which the halo is removed by
the collimators
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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ABSTRACT: The Next Linear Collider main linacs are 13 km linear accelerators
which each contain approximately 750 hybrid iron/permanent-magnet
quadrupoles in a FODO array. The small amount of vertical emittance
dilution permitted in the main linacs implies a tight tolerance on the
RMS distance between the beam and the centers of the quads. We describe
two methods for measuring the offsets between the quads and their
integrated beam position monitors, and three algorithms for steering the
main linac to minimize the emittance dilution. Simulation studies of the
alignment and steering algorithms are presented
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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ABSTRACT: Beam-based feedback systems play an essential role in the
operation of high energy electron-positron linear colliders. Ground
motion, vibration and other disturbances can significantly alter the
beam trajectory or degrade the beam quality. Feedback systems are
required for long term stability and for ease and efficiency of
operation. Trajectory feedback for the Next Linear Collider (NLC) has
been studied extensively to understand both the achievable orbit quality
and the time response characteristics. More recently, these studies have
been extended to evaluate performance in the presence of ground motion
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
