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J. Leibfritz,
R. Andrews,
C. M. Baffes,
K. Carlson,
B. Chase,
M. D. Church,
E. R. Harms,
A. L. Klebaner,
M. Kucera,
A. Martinez,
S. Nagaitsev,
L. E. Nobrega,
P. Piot,
J. Reid, M. Wendt,
S. J. Wesseln
[show abstract]
[hide abstract]
ABSTRACT: The Advanced Superconducting Test Acccelerator (ASTA) is being constructed at
Fermilab. The existing New Muon Lab (NML) building is being converted for this
facility. The accelerator will consist of an electron gun, injector, beam
acceleration section consisting of 3 TTF-type or ILC-type cryomodules, multiple
downstream beamlines for testing diagnostics and conducting various beam tests,
and a high power beam dump. When completed, it is envisioned that this facility
will initially be capable of generating a 750-MeV electron beam with ILC beam
intensity. An expansion of this facility was recently completed that will
provide the capability to upgrade the accelerator to a total beam energy of
1.5-GeV. Two new buildings were also constructed adjacent to the ASTA facility
to house a new cryogenic plant and multiple superconducting RF (SRF) cryomodule
test stands. In addition to testing accelerator components, this facility will
be used to test RF power systems, instrumentation, and control systems for
future SRF accelerators such as the ILC and Project-X. This paper describes the
current status and overall plans for this facility.
01/2013;
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N. Eddy,
C. Briegel,
B. Fellenz,
E. Gianfelice-Wendt,
P. Prieto,
R. Rechenmacher,
A. Semenov,
D. Voy, M. Wendt,
D. Zhang,
N. Terunuma,
J. Urakawa
[show abstract]
[hide abstract]
ABSTRACT: A beam position monitor (BPM) upgrade at the KEK Accelerator Test Facility
(ATF) damping ring has been accomplished, carried out by a KEK/FNAL/SLAC
collaboration under the umbrella of the global ILC R&D effort. The upgrade
consists of a high resolution, high reproducibility read-out system, based on
analog and processing, and also implements a new automatic gain error
correction schema. The technical concept and realization as well as results of
beam studies are presented.
09/2012;
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J. Leibfritz,
R. Andrews,
K. Carlson,
B. Chase,
M. Church,
E. Harms,
A. Klebaner,
M. Kucera,
S. Lackey,
A. Martinez,
S. Nagaitsev,
L. Nobrega,
P. Piot,
J. Reid, M. Wendt,
S. Wesseln
[show abstract]
[hide abstract]
ABSTRACT: A superconducting RF accelerator test facility is being constructed at
Fermilab. The existing New Muon Lab (NML) building is being converted for this
facility. The accelerator will consist of an electron gun, injector, beam
acceleration section consisting of 3 TTF-type or ILC-type cryomodules, multiple
downstream beam lines for testing diagnostics and conducting various beam
tests, and a high power beam dump. When completed, it is envisioned that this
facility will initially be capable of generating an 810 MeV electron beam with
ILC beam intensity. Expansion plans of the facility are underway that will
provide the capability to upgrade the accelerator to a total beam energy of 1.5
GeV. In addition to testing accelerator components, this facility will be used
to test RF power equipment, instrumentation, LLRF and controls systems for
future SRF accelerators such as the ILC and Project-X. This paper describes the
current status and overall plans for this facility.
08/2012;
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[show abstract]
[hide abstract]
ABSTRACT: Beam-excited higher order modes (HOM) in accelerating cavities contain
transverse beam position information. Previous studies have narrowed down three
modal options for beam position diagnostics in the third harmonic 3.9 GHz
cavities at FLASH. Localized modes in the beam pipes at approximately 4.1 GHz
and in the fifth cavity dipole band at approximately 9 GHz were found, that can
provide a local measurement of the beam position. In contrast, propagating
modes in the first and second dipole bands between 4.2 and 5.5 GHz can reach a
better resolution. All the options were assessed with a specially designed test
electronics built by Fermilab. The aim is to define a mode or spectral region
suitable for the HOM electronics. Two data analysis techniques are used and
compared in extracting beam position information from the dipole HOMs: direct
linear regression and singular value decomposition. Current experiments suggest
a resolution of 50 {\mu}m accuracy in predicting local beam position using
modes in the fifth dipole band, and a global resolution of 20 {\mu}m over the
complete module. Based on these results we decided to build a HOM electronics
for the second dipole band and the fifth dipole band, so that we will have both
high resolution measurements for the whole module, and localized measurements
for individual cavity. The prototype electronics is being built by Fermilab and
planned to be tested in FLASH by the end of 2012.
08/2012;
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[show abstract]
[hide abstract]
ABSTRACT: A common-mode free cavity BPM is currently under development at Fermilab
within the ILC-CLIC collaboration. This monitor will be operated in a CLIC Main
Linac multi-bunch regime, and needs to provide both, high spatial and time
resolution. We present the design concept, numerical analysis, investigation on
tolerances and error effects, as well as simulations on the signal response
applying a multi-bunch stimulus.
07/2012;
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[show abstract]
[hide abstract]
ABSTRACT: In frame of the development of a high resolution BPM system for the CLIC Main
Linac we present the design of a cavity BPM prototype. It consists of a
waveguide loaded dipole mode resonator and a monopole mode reference cavity,
both operating at 15 GHz, to be compatible with the bunch frequencies at the
CLIC Test Facility. Requirements, design concept, numerical analysis, and
practical considerations are discussed.
07/2012;
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A Lyapin,
H J Schreiber,
M Viti,
C Adolphsen,
R Arnold,
S Boogert,
G Boorman,
M V Chistiakova,
F Gournaris,
V Duginov, [......],
T Orimoto,
E Petigura,
M Sadre-Bazzaz,
M Slater,
Z Szalata,
M Thomson,
D Ward, M Wendt,
M Wing,
M Woods
[show abstract]
[hide abstract]
ABSTRACT: The International Linear Collider (ILC) and other proposed high energy e+e− machines
aim to measure with unprecedented precision Standard Model quantities and new, not yet
discovered phenomena. One of the main requirements for achieving this goal is a measurement of
the incident beam energy with an uncertainty close to 10^{−4}. This article presents the analysis of
data from a prototype energy spectrometer commissioned in 2006-2007 in SLAC’s End Station A
beamline. The prototype was a 4-magnet chicane equipped with beam position monitors measuring
small changes of the beam orbit through the chicane at different beam energies. A single bunch
energy resolution close to 5 · 10^{−4} was measured, which is satisfactory for most scenarios. We
also report on the operational experience with the chicane-based spectrometer and suggest ways of
improving its performance.
Journal of Instrumentation 02/2011; 6(2):P02002-P02020. · 1.87 Impact Factor
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S. Molloy,
J. Frisch,
J. May,
D. McCormick,
T. Smith,
N. Baboi,
O. Hensler,
L. Petrosyan,
N. Eddy,
L. Piccoli,
R. Rechenmacher,
M. Ross, M. Wendt,
O. Napoly,
R.C. Paparella,
C. Simon
[show abstract]
[hide abstract]
ABSTRACT: It is well known that an electron beam excites higher order modes (HOMs) as it passes through an accelerating cavity. The properties of the excited signal depend not only on the cavity geometry, but on the charge and trajectory of the beam. It is, therefore, possible to use these signals as a monitor of the beam's position. Electronics were installed on all forty cavities present in the FLASH linac in DESY. These electronics filter out a mode known to have a strong dependence on the beam's position, and mix this down to a frequency suitable for digitisation. An analysis technique based on singular value decomposition (SVD) was developed to calculate the beam's trajectory from the output of the electronics. The entire system has been integrated into the FLASH control 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]
[hide abstract]
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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W. Ackermann,
DESY Maschinenphysik,
G. Asova,
V. Ayvazyan,
A. Azima,
N. Baboi,
J. Bähr,
V. Balandin,
B. Beutner,
A Brandt, [......],
M. Wellhöfer, M. Wendt,
I. Will,
A. Winter,
K. Wittenburg,
W. Wurth,
P. Yeates,
M.V. Yurkov,
I. Zagorodnov,
K. Zapfe
Nature Photonics 02/2007; 1:336. · 29.28 Impact Factor
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V. Ayvazyan,
N. Baboi,
J. Bähr,
V. Balandin,
B. Beutner,
A Brandt,
I Bohnet,
A. Bolzmann,
R Brinkmann,
O.I. Brovko, [......],
T. Weiland,
H. Weise, M. Wendt,
I. Will,
A. Winter,
K. Wittenburg,
M.V. Yurkov,
I. Zagorodnov,
P. Zambolin,
K. Zapfe
The European Physical Journal D 01/2006; 37:297. · 1.48 Impact Factor
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M. Ross,
J. Frisch,
K.E. Hacker,
R.M. Jones,
D. McCormick,
C. O'Connell,
T. Smith,
O. Napoly,
R. Paparella,
N. Baboi, M. Wendt
[show abstract]
[hide abstract]
ABSTRACT: Each nine cell superconducting (SC) accelerator cavity in the TESLA Test Facility (TTF) at DESY [1] has two higher order mode (HOM) couplers that efficiently remove the HOM power [2]. They can also provide useful diagnostic signals. The most interesting modes are in the first 2 cavity dipole passbands. They are easy to identify and their amplitude depends linearly on the beam offset from the cavity axis making them excellent beam position monitors (BPM). By steering the beam through an eight-cavity cryomodule, we can use the HOM signals to estimate internal residual alignment errors and minimize wakefield related beam emittance growth. We built and tested a time-domain based waveform recorder system that captures information from each mode in these two bands on each beam pulse. In this paper we present a preliminary experimental study of the single-bunch generated HOM signals at the TTF linac including estimates of cavity alignment precision and HOM BPM resolution.
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
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[show abstract]
[hide abstract]
ABSTRACT: Two 2×7-cell Nb superstructures have been tested with beam during the last TESLA Test Facility (TTF) linac run in summer 2002. The structures have been operated at 2 K in the standard TTF cryomodule and have been installed in the linac after the injector. We report on the bunch-to-bunch energy stability test which showed that energy stored in the superstructure could be refilled in the time between two passing bunches. The goal to keep the bunch-to-bunch energy stability below 5·10<sup>-4</sup> has been achieved.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
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[show abstract]
[hide abstract]
ABSTRACT: Superstructures, groups of weakly coupled cavities fed through a single power coupler, are currently investigated as a more cost effective alternative to the 9-cell TESLA cavities. Two Nb prototypes of the superstructure have been built, consisting of two 7-cell cavities, and installed in the TESLA Test Facility at DESY. The HOM damping of these superstructures has been investigated with a modulated beam using the method described in. A charge modulation imposed on the 54 MHz bunch train excites HOM at frequencies n · f<sub>b</sub> ± f<sub>mod</sub>, where n is an integer, f<sub>b</sub> = 54 MHz is the bunch frequency and f<sub>mod</sub> is the charge modulation frequency between 0.5 and 27 MHz. The effects of the excited HOMs on the beam transverse position are observed at a downstream BPM, followed by a direct analysis of the modes at the HOM couplers.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
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J. Sekutowicz,
C. Albrecht,
V. Ayvazyan,
R. Bandelmann,
T. Buttner,
P. Castro,
S. Choroba,
J. Eschke,
B. Faatz,
A. Gossel, [......],
M. Liepe,
M. Huening,
M. Ferrario,
E. Plawski,
C. Pagani,
N. Baboi,
H. Chen,
H. Wenhui,
C. Tang,
S. Zheng
[show abstract]
[hide abstract]
ABSTRACT: After three years of preparation, two superstructures, each made of two superconducting 7-cell weakly coupled subunits, have been installed in the TESLA Test Facility linac (TTF) for the cold- and beam test. The energy stability, the HOMs damping, the frequency and the field adjustment methods were tested. The measured results confirmed expectation on the superstructure performance and proved that alternative layout for the 800 GeV upgrade of the TESLA collider, as it was proposed in TDR, is feasible. We report on the test and give here an overview of its results which are commented in more detail elsewhere in these Proceedings.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
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V. Ayvazyan,
N. Baboi,
I. Bohnet,
R. Brinkmann,
M. Castellano,
P. Castro,
L. Catani,
S. Choroba,
A. Cianchi,
M. Dohlus, [......],
R. Wanzenberg,
T. Weiland,
H. Weise, M. Wendt,
T. Wilhein,
I. Will,
K. Wittenburg,
S. Wolff,
M.V. Yurkov,
K. Zapfe
[show abstract]
[hide abstract]
ABSTRACT: We present experimental evidence that the free-electron laser at the TESLA Test Facility has reached the maximum power gain
of 107 in the vacuum ultraviolet (VUV) region at wavelengths between 80 and 120 nm. At saturation the FEL emits short pulses with
GW peak power and a high degree of transverse coherence. The radiation pulse length can be adjusted between 30 fs and 100
fs. Radiation spectra and fluctuation properties agree with the theory of high gain, single-pass free-electron lasers starting
from shot noise.
The European Physical Journal D 06/2002; 20(1):149-156. · 1.48 Impact Factor
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V Ayvazyan,
N Baboi,
I Bohnet,
R Brinkmann,
M Castellano,
P Castro,
L Catani,
S Choroba,
A Cianchi,
M Dohlus, [......],
V Verzilov,
R Wanzenberg,
T Weiland,
H Weise, M Wendt,
I Will,
S Wolff,
K Wittenburg,
M V Yurkov,
K Zapfe
[show abstract]
[hide abstract]
ABSTRACT: Experimental results are presented from vacuum-ultraviolet free-electron laser (FEL) operating in the self-amplified spontaneous emission (SASE) mode. The generation of ultrashort radiation pulses became possible due to specific tailoring of the bunch charge distribution. A complete characterization of the linear and nonlinear modes of the SASE FEL operation was performed. At saturation the FEL produces ultrashort pulses (30-100 fs FWHM) with a peak radiation power in the GW level and with full transverse coherence. The wavelength was tuned in the range of 95-105 nm.
Physical Review Letters 04/2002; 88(10):104802. · 7.37 Impact Factor
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G.A. Blair,
J. Frisch,
K. Honkavaara,
T. Kamps,
F. Poirier,
I.N. Ross,
M. Ross,
H. Schlarb,
P. Schmuser,
S. Schreiber,
D. Sertore,
N. Walker, M. Wendt,
K. Wittenburg
[show abstract]
[hide abstract]
ABSTRACT: Compton scattering techniques for the measurement of the
transverse beam size of particle beams at future linear colliders (FLC)
are proposed. At several locations of the beam delivery system (BDS) of
the FLC, beam spot sizes ranging from several hundreds to a few
micrometers have to be measured. This is necessary to verify beam
optics, to obtain the transverse beam emittance, and to achieve the
highest possible luminosity. The large demagnification of the beam in
the BDS and the high beam power puts extreme conditions on any measuring
device. With conventional techniques at their operational limit in FLC
scenarios, new methods for the detection of the transverse beam size
have to be developed. For this laser based techniques are proposed
capable of measuring high power beams with sizes in the micrometer
range. In this paper general aspects and critical issues of a generic
device are outlined and specific solutions proposed. Plans to install a
laser wire experiment at an accelerator test facility are
presented
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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C. Magne,
M. Jablonka,
M. Lalot,
V. Lethiers,
M. Luong,
O. Napoly,
N. Baboi,
P. Castro,
A. Gossel,
M. Huning,
G. Kreps,
M. Liepe,
M. Minty,
S. Schreiber,
D. Sertore, M. Wendt
[show abstract]
[hide abstract]
ABSTRACT: This paper reports on recent beam measurements of higher order
modes in the TESLA Test Facility (TTF) accelerating modules. Using bunch
trains of about 0.5 ms with 54 MHz bunch repetition and up to 90%
modulated intensity, transverse higher order modes are resonantly
excited when the beam is offset and their frequency on resonance with
the modulation frequency. With this method, the trapped modes can be
excited and their counteraction on the beam observed on a wide-band BPM
downstream of the module. Scanning the modulation frequency from 0 to 27
MHz allows a systematic investigation of all possible dangerous modes in
the modules
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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G A Blair,
J Frisch,
K Honhavaara,
T. Kamps,
F. Poirier,
I N Ross,
M Ross,
H. Schlarb,
P Schmuser,
S Schreiber,
D. Sertore,
N. Walker, M. Wendt,
K. Wittenburg
