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ABSTRACT: This paper presents the fabrication of an ion source using carbon nanoparticle field emitters for a micro time-of-flight mass spectrometer (TOFMS). The micro TOFMS consists of a glass substrate with several electrodes and a silicon substrate with carbon nanoparticle (CNP) field emitters. The type of CNP field emitters is the triode type with which we can control the emission current at low voltage. The CNP layer is grown by hot-filament chemical-vapor deposition (HFCVD). The size of the assembled device is 10 times10 times 1 mm . The emission current of the ion source can be controlled from 0 to 94.3 muA when the gate voltage varies from 0 to 85 V.
Solid-State Sensors, Actuators and Microsystems Conference, 2007. TRANSDUCERS 2007. International; 07/2007
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M J Hogan,
C E Clayton,
C Huang,
P Muggli,
S Wang,
B E Blue,
D Walz,
K A Marsh,
C L O'Connell, S Lee,
R Iverson,
F-J Decker,
P Raimondi,
W B Mori,
T C Katsouleas,
C Joshi,
R H Siemann
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ABSTRACT: We report on the first study of the dynamic transverse forces imparted to an ultrarelativistic positron beam by a long plasma in the underdense regime. Focusing of the 28.5 GeV beam is observed from time-resolved beam profiles after the 1.4 m plasma. The strength of the imparted force varies along the approximately 12 ps full length of the bunch as well as with plasma density. Computer simulations substantiate the longitudinal aberration seen in the data and reveal mechanisms for emittance degradation.
Physical Review Letters 06/2003; 90(20):205002. · 7.37 Impact Factor
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S. Deng,
T. Katsouleas, S. Lee,
P. Muggli,
W. B. Mori,
R. Hemker,
C. Ren,
C. Huang,
E. Dodd,
B. E. Blue,
C. E. Clayton,
C. Joshi,
S. Wang,
F.‐J. Decker,
M. J. Hogan,
R. H. Iverson,
C. O’Connell,
P. Raimondi,
D. Walz
[show abstract]
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ABSTRACT: 3‐D Particle‐in‐cell OSIRIS simulations of the current E‐162 Plasma Wakefield Accelerator Experiment are presented in which a number of non‐ideal conditions are modeled simultaneously. These include tilts on the beam in both planes, asymmetric beam emittance, beam energy spread and plasma inhomogeneities both longitudinally and transverse to the beam axis. The relative importance of the non‐ideal conditions is discussed and a worstcase estimate of the effect of these on energy gain is obtained. The simulation output is then propagated through the downstream optics, drift spaces and apertures leading to the experimental diagnostics to provide insight into the differences between actual beam conditions and what is measured. The work represents a milestone in the level of detail of simulation comparisons to plasma experiments. © 2002 American Institute of Physics
AIP Conference Proceedings. 12/2002; 647(1):592-599.
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ABSTRACT: The interaction between a low density electron cloud in a circular particle accelerator with a circulating charged particle beam is considered. The particle beam’s space charge attracts the cloud, enhancing the cloud density near the beam axis. Beam‐ cloud interaction is studied with a plasma wakefield accelerator simulation code and the results are benchmarked against an existing code. The restoring force on the off‐centered beam due to the cloud’s space charge is studied. The force is stronger at the tail than it is at the head due to the cloud compression near the tail of the beam. The beam dynamics over 20Km of the SPS ring at CERN is studied and the head‐tail dephasing is observed. © 2002 American Institute of Physics
AIP Conference Proceedings. 12/2002; 647(1):224-231.
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Shuoqin Wang,
C E Clayton,
B E Blue,
E S Dodd,
K A Marsh,
W B Mori,
C Joshi, S Lee,
P Muggli,
T Katsouleas,
F J Decker,
M J Hogan,
R H Iverson,
P Raimondi,
D Walz,
R Siemann,
R Assmann
[show abstract]
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ABSTRACT: The successful utilization of an ion channel in a plasma to wiggle a 28.5-GeV electron beam to obtain broadband x-ray radiation is reported. The ion channel is induced by the electron bunch as it propagates through an underdense 1.4-meter-long lithium plasma. The quadratic density dependence of the spontaneously emitted betatron x-ray radiation and the divergence angle of approximately (1-3)x10(-4) radian of the forward-emitted x-rays as a consequence of betatron motion in the ion channel are in good agreement with theory. The absolute photon yield and the peak spectral brightness at 14.2-keV photon energy are estimated.
Physical Review Letters 05/2002; 88(13):135004. · 7.37 Impact Factor
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C E Clayton,
B E Blue,
E S Dodd,
C Joshi,
K A Marsh,
W B Mori,
S Wang,
P Catravas,
S Chattopadhyay,
E Esarey, [......],
R Assmann,
F J Decker,
M J Hogan,
R Iverson,
P Raimondi,
R H Siemann,
D Walz,
T Katsouleas, S Lee,
P Muggli
[show abstract]
[hide abstract]
ABSTRACT: The transverse dynamics of a 28.5-GeV electron beam propagating in a 1.4 m long, (0-2)x10(14) cm(-3) plasma are studied experimentally in the underdense or blowout regime. The transverse component of the wake field excited by the short electron bunch focuses the bunch, which experiences multiple betatron oscillations as the plasma density is increased. The spot-size variations are observed using optical transition radiation and Cherenkov radiation. In this regime, the behavior of the spot size as a function of the plasma density is well described by a simple beam-envelope model. Dynamic changes of the beam envelope are observed by time resolving the Cherenkov light.
Physical Review Letters 05/2002; 88(15):154801. · 7.37 Impact Factor
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C. Joshi,
B. Blue,
C. E. Clayton,
E. Dodd,
C. Huang,
K. A. Marsh,
W. B. Mori,
S. Wang,
M. J. Hogan,
C. O’Connell,
R. Siemann,
D. Watz,
P. Muggli,
T. Katsouleas, S. Lee
[show abstract]
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ABSTRACT: An intense, high-energy electron or positron beam can have focused intensities rivaling those of today’s most powerful laser beams. For example, the 5 ps (full-width, half-maximum), 50 GeV beam at the Stanford Linear Accelerator Center (SLAC) at 1 kA and focused to a 3 micron rms spot size gives intensities of >1020 W/cm−2 at a repetition rate of >10 Hz. Unlike a ps or fs laser pulse which interacts with the surface of a solid target, the particle beam can readily tunnel through tens of cm of steel. However, the same particle beam can be manipulated quite effectively by a plasma that is a million times less dense than air! This is because of the incredibly strong collective fields induced in the plasma by the Coulomb force of the beam. The collective fields in turn react back onto the beam leading to many clearly observable phenomena. The beam paraticles can be: (1) Deflected leading to focusing, defocusing, or even steering of the beam; (2) undulated causing the emission of spontaneous betatron x-ray radiation and; (3) accelerated or decelerated by the plasma fields. Using the 28.5 GeV electron beam from the SLAC linac a series of experiments have been carried out that demonstrate clearly many of the above mentioned effects. The results can be compared with theoretical predictions and with two-dimensional and three-dimensional, one-to-one, particle-in-cell code simulations. These phenomena may have practical applications in future technologies including optical elements in particle beam lines, synchrotron light sources, and ultrahigh gradient accelerators. © 2002 American Institute of Physics.
Physics of Plasmas 04/2002; 9(5):1845-1855. · 2.15 Impact Factor
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ABSTRACT: This Letter examines the electron-hosing instability in relation to the drivers of current and future plasma-wakefield experiments using fully three-dimensional particle-in-cell simulation models. The simulation results are compared to numerical solutions and to asymptotic solutions of the idealized analytic equations. The measured growth rates do not agree with the existing theory and the behavior is shown to depend sensitively on beam length, shape, and charge. We find that even when severe hosing occurs the wake can remain relatively stable.
Physical Review Letters 04/2002; 88(12):125001. · 7.37 Impact Factor
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R. A. Fonseca,
L. O. Silva,
F. S. Tsung,
V. K. Decyk,
W. Lu,
C. Ren,
W. B. Mori,
S. Deng, S. Lee,
T. Katsouleas,
J. C. Adam
[show abstract]
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ABSTRACT: We describe OSIRIS, a three-dimensional, relativistic, massively parallel, object oriented particle-in-cell code for modeling
plasma based accelerators. Developed in Fortran 90, the code runs on multiple platforms (Cray T3E, IBM SP, Mac clusters) and
can be easily ported to new ones. Details on the code’s capabilities are given. We discuss the object-oriented design of the
code, the encapsulation of system dependent code and the parallelization of the algorithms involved. We also discuss the implementation
of communications as a boundary condition problem and other key characteristics of the code, such as the moving window, open-space
and thermal bath boundaries, arbitrary domain decomposition, 2D (cartesian and cylindric) and 3D simulation modes, electron
sub-cycling, energy conservation and particle and field diagnostics. Finally results from three-dimensional simulations of
particle and laser wakefield accelerators are presented, in connection with the data analysis and visualization infrastructure
developed to post-process the scalar and vector results from PIC simulations.
12/2001: pages 342-351;
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ABSTRACT: Plasma-wakefield excitation by positron beams is examined in a regime for which the plasma dynamics are highly nonlinear. Three dimensional particle-in-cell simulations and physical models are presented. In the nonlinear wake regime known as the blowout regime for electrons, positron wakes exhibit an analogous "suck-in" behavior. Although analogous, the two wakefield cases are quite different in terms of their amplitudes, wavelengths, waveforms, transverse profiles, and plasma density dependence. In a homogenous plasma, nonlinear positron wakes are smaller than those of the corresponding electron case. However, hollow channels are shown to enhance the amplitude of the positron wakes.
Physical Review E 11/2001; 64(4 Pt 2):045501. · 2.26 Impact Factor
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P Catravas,
S Chattopadhyay,
E Esarey,
W P Leemans,
R Assmann,
F J Decker,
M J Hogan,
R Iverson,
R H Siemann,
D Walz,
D Whittum,
B Blue,
C Clayton,
C Joshi,
K A Marsh,
W B Mori,
S Wang,
T Katsouleas, S Lee,
P Muggli
[show abstract]
[hide abstract]
ABSTRACT: Emissions produced or initiated by a 30-GeV electron beam propagating through a approximately 1-m long heat pipe oven containing neutral and partially ionized vapor have been measured near atomic spectral lines in a beam-plasma wakefield experiment. The Cerenkov spatial profile has been studied as a function of oven temperature and pressure, observation wavelength, and ionizing laser intensity and delay. The Cerenkov peak angle is affected by the creation of plasma, and estimates of neutral and plasma density have been extracted. Increases in visible background radiation, consistent with increased plasma recombination emissions due to dissipation of wakefields, were simultaneously measured.
Physical Review E 11/2001; 64(4 Pt 2):046502. · 2.26 Impact Factor
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P. Catravas,
S. Chattopadhyay,
E. Esarey,
W. P. Leemans,
R. Assmann,
B. Blue,
C. Clayton,
C. Joshi,
K. A. Marsh,
W. B. Mori,
S. Wang,
T. Katsouleas, S. Lee,
P. Muggli
[show abstract]
[hide abstract]
ABSTRACT: Emissions produced or initiated by a 30-GeV electron beam propagating through a ∼1-m long heat pipe oven containing neutral and partially ionized vapor have been measured near atomic spectral lines in a beam-plasma wakefield experiment. The Cerenkov spatial profile has been studied as a function of oven temperature and pressure, observation wavelength, and ionizing laser intensity and delay. The Cerenkov peak angle is affected by the creation of plasma, and estimates of neutral and plasma density have been extracted. Increases in visible background radiation, consistent with increased plasma recombination emissions due to dissipation of wakefields, were simultaneously measured.
Phys. Rev. E. 09/2001; 64(4).
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P Muggli, S Lee,
T Katsouleas,
R Assmann,
F J Decker,
M J Hogan,
R Iverson,
P Raimondi,
R H Siemann,
D Walz,
B Blue,
C E Clayton,
E Dodd,
R A Fonseca,
R Hemker,
C Joshi,
K A Marsh,
W B Mori,
S Wang
Nature 06/2001; 411(6833):43. · 36.28 Impact Factor
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P. Muggli,
M.J. Hogan,
B.E. Blue,
C. O'Connell,
R.H. Siemann,
D. Walz,
R. Assmann,
C.E. Clayton,
F.-J. Decker,
E.S. Dodd,
R.H. Iverson,
C. Joshi,
T.C. Katsouleas, S. Lee,
K.A. Marsy,
W.B. Mori,
P. Rainiondi,
S. Wang
[show abstract]
[hide abstract]
ABSTRACT: A plasma wakefield acceleration experiment is conducted at the
Stanford Linear Accelerator Center. This experiment addresses the issues
relevant to a meter-long plasma accelerator module in the context of a
high-energy accelerator
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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Shuoqin Wang,
C.E. Clayton,
B.E. Blue,
E.S. Dodd,
C.-K. Huang,
K.A. Marsh,
W.B. Mori,
C. Joshi, S. Lee,
P. Muggli,
T. Katsouleas,
F.J. Decker,
M.J. Hogan,
R.H. Iverson,
P. Riamondi,
D. Walz,
R. Siemann,
R. Assmann
[show abstract]
[hide abstract]
ABSTRACT: An experiment is being carried out at the Stanford Linear
Accelerator Center (SLAC) to see if an ion channel can wiggle a beam of
ultra-relativistic electrons to produce X-ray radiation. The goal is to
create an intense source of undulator radiation using a plasma wiggler
in the 1-10 keV range and also to determine the suitability of such an
electrostatic wiggler to create a coherent beam of X-rays via the ion
channel laser mechanisml. Here we give some of the scaling laws for the
power and frequency distribution of the spontaneous emission from
sending an electron beam through such an ion channel. Some initial
experimental observations are also presented
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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B. Blue,
C.E. Clayton,
E. Dodd,
K. Marsh,
W.B. Mori,
S. Wang,
C. Joshi,
R. Assmann,
F.-J. Decker,
M.J. Hogan,
R.H. Iverson,
P. Raimondi,
D. Walz,
R.H. Siemann, S. Lee,
P. Muggli,
T. Katsouleas
[show abstract]
[hide abstract]
ABSTRACT: The E157 experiment is designed to demonstrate high gradient
plasma wake field acceleration over a significant length. It has been
suggested that the electron hose instability of the drive beam will
degrade the performance of this experiment because the hosing tail
electrons will not fully sample the highest acceleration field. In this
paper a parasitic experiment designed to test the extent of the hosing
instability is described. In particular, we discuss how the initial beam
conditions are determined so that the extent to which any transverse
perturbations grow due to hosing can be determined
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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P Muggli, S Lee,
T Katsouleas,
R Assamnn,
F J Decker,
M J Hogan,
R Iverson,
P Raimondi,
R H Siemann,
D Walz,
B Blue,
C E Clayton,
E Dodd,
R A Fonseca,
R Hemker,
C Joshi,
K A Marsh,
W B Mori,
S Wang
Physical Review Special Topics - Accelerators and Beams 01/2001; 4(9). · 1.52 Impact Factor
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P Muggli, S Lee,
T Katsouleas,
R Assmann,
F J Decker,
M J Hogan,
R Iverson,
P Raimondi,
R H Siemann,
D Walz,
B Blue,
C E Clayton,
E Dodd,
R A Fonseca,
R Hemker,
C Joshi,
K A Marsh,
W B Mori,
S Q Wang
Nature 01/2001; 411(6833):43-43. · 36.28 Impact Factor
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ABSTRACT: Full-scale particle-in-cell simulations of a meter-long plasma wakefield accelerator (PWFA) are presented in two dimensions. The results support the design of a current PWFA experiment in the nonlinear blowout regime where analytic solutions are intractable. A relativistic electron bunch excites a plasma wake that accelerates trailing particles at rates of several hundred MeV/m. A comparison is made of various simulation codes, and a parallel object-oriented code OSIRIS is used to model a full meter of acceleration. Excellent agreement is obtained between the simulations and analytic expressions for the transverse betatron oscillations of the beam. The simulations are used to develop scaling laws for designing future multi-GeV accelerator experiments.
Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics 07/2000; 61(6 Pt B):7014-21.
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M. J. Hogan,
R. Assmann,
F.-J. Decker,
R. Iverson,
P. Raimondi,
S. Rokni,
R. H. Siemann,
D. Walz,
D. Whittum,
B. Blue, [......],
K. A. Marsh,
W. B. Mori,
S. Wang,
T. Katsouleas, S. Lee,
P. Muggli,
P. Catravas,
S. Chattopadhyay,
E. Esarey,
W. P. Leemans
[show abstract]
[hide abstract]
ABSTRACT: In the E-157 experiment now being conducted at the Stanford Linear Accelerator Center, a 30 GeV electron beam of 2×1010 electrons in a 0.65-mm-long bunch is propagated through a 1.4-m-long lithium plasma of density up to 2×1014 e−/cm3. The initial beam density is greater than the plasma density, and the head of the bunch expels the plasma electrons leaving behind a uniform ion channel with transverse focusing fields of up to several thousand tesla per meter. The initial transverse beam size with σ = 50–100 μm is larger than the matched size of 5 μm resulting in up to three beam envelope oscillations within the plasma. Time integrated optical transition radiation is used to study the transverse beam profile immediately before and after the plasma and to characterize the transverse beam dynamics as a function of plasma density. The head of the bunch deposits energy into plasma wakes, resulting in longitudinal accelerating fields which are witnessed by the tail of the same bunch. A time-resolved Cherenkov imaging system is located in an energy dispersive plane downstream of the plasma. It images the beam onto a streak camera allowing time-resolved measurements of the beam energy spectrum as a function of plasma density. Preliminary experimental data from the first three runs are compared to theory and computer simulations. © 2000 American Institute of Physics.
Physics of Plasmas 04/2000; 7(5):2241-2248. · 2.15 Impact Factor
