- Experimental study of large-amplitude perturbations in space-charge dominated beams
Author(s): K. Tian, R. A. Kishek, I. Haber, M. Reiser, and P. G. O’Shea
Detailed experimental measurements are presented concerning the propagation of space-charge waves of varying amplitudes in an intense, charged-particle beam. A short perturbation to the density profile is applied at the electron gun, and both current and mean energy profiles are measured at two loca...
[Phys. Rev. ST Accel. Beams 13, 034201] Published Mon Mar 08, 2010
- Optical afterburner for an x-ray free electron laser as a tool for pump-probe experiments
Author(s): E. L. Saldin, E. A. Schneidmiller, and M. V. Yurkov
We propose a new scheme for two-color operation of an x-ray self-amplified spontaneous emission free electron laser (SASE FEL). The scheme is based on an intrinsic feature of such a device: chaotic modulations of electron beam energy and energy spread on the scale of FEL coherence length are convert...
[Phys. Rev. ST Accel. Beams 13, 030701] Published Fri Mar 05, 2010
- Fully 3D multiple beam dynamics processes simulation for the Fermilab Tevatron
Author(s): E. G. Stern, J. F. Amundson, P. G. Spentzouris, and A. A. Valishev
We present validation and results from a simulation of the Fermilab Tevatron including multiple beam dynamics effects. The essential features of the simulation include a fully 3D strong-strong beam-beam particle-in-cell Poisson solver, interactions among multiple bunches and both head-on and long-ra...
[Phys. Rev. ST Accel. Beams 13, 024401] Published Thu Feb 25, 2010
- Suppressing and initiation of multipactor discharge on a dielectric by an external dc bias
Author(s): O. A. Ivanov, M. A. Lobaev, V. A. Isaev, and A. L. Vikharev
The results of studying experimentally the influence of an external dc electric field on the multipactor threshold on the surface of a dielectric (quartz) are presented. In the experiments, a high-Q-factor microwave resonator was excited at the TE_{012} mode in the 3-cm wavelength band. The dependen...
[Phys. Rev. ST Accel. Beams 13, 022004] Published Thu Feb 25, 2010
- X-ray pinhole camera resolution and emittance measurement
Author(s): Cyrille Thomas, Guenther Rehm, Ian Martin, and Riccardo Bartolini
Third generation synchrotron light sources are characterized by a low emittance and a low emittance coupling. Some light sources are already operating with extremely low coupling close to 0.1%. Measurement of the transverse beam size is generally used to measure the emittance and the coupling. To th...
[Phys. Rev. ST Accel. Beams 13, 022805] Published Wed Feb 24, 2010
- Beam injection with a pulsed sextupole magnet in an electron storage ring
Author(s): Hiroyuki Takaki, Norio Nakamura, Yukinori Kobayashi, Kentaro Harada, Tsukasa Miyajima, Akira Ueda, Shinya Nagahashi, Miho Shimada, Takashi Obina, and Tohru Honda
We have developed a new beam injection system with a single pulsed sextupole magnet (PSM) at the photon factory storage ring (PF ring) in the High Energy Accelerator Research Organization. We demonstrated beam injection with this system and succeeded in storing a beam current of 450 mA, which is th...
[Phys. Rev. ST Accel. Beams 13, 020705] Published Wed Feb 24, 2010
- Smith-Purcell radiation from a charge moving above a grating of finite length and width
Author(s): Amit S. Kesar
Smith-Purcell radiation (SPR), emitted when a charge passes above a periodic grating, is important for applications such as terahertz production and nondestructive bunch-length diagnostics. The grating width is shown to become an important parameter for accurately predicting the radiation, and espec...
[Phys. Rev. ST Accel. Beams 13, 022804] Published Tue Feb 23, 2010
- High precision beam momentum determination in a synchrotron using a spin-resonance method
Author(s): P. Goslawski, A. Khoukaz, R. Gebel, M. Hartmann, A. Kacharava, A. Lehrach, B. Lorentz, R. Maier, M. Mielke, M. Papenbrock, D. Prasuhn, R. Stassen, H. J. Stein, H. Stockhorst, H. Ströher, and C. Wilkin
In order to measure the mass of the η meson with high accuracy using the dp→ ^{3} Heη reaction, the momentum of the circulating deuteron beam in the Cooler Synchrotron COSY of the Forschungszentrum Jülich has to be determined with unprecedented precision. This has been achieved by studying the ...
[Phys. Rev. ST Accel. Beams 13, 022803] Published Tue Feb 23, 2010
- Eccentric-fluted beam pipes to damp quadrupole higher-order modes
Author(s): M. Sawamura, T. Furuya, H. Sakai, T. Takahashi, K. Umemori, and K. Shinoe
An eccentric-fluted beam pipe is proposed to damp quadrupole modes in a cavity. The eccentric flutes act as a mode converter from quadrupole to dipole. Optimizing the parameters of the eccentric-fluted beam pipe allows sufficient damping of both degenerate quadrupole modes. The external Q values of ...
[Phys. Rev. ST Accel. Beams 13, 022003] Published Tue Feb 23, 2010
- Detailed characterization of electron sources yielding first demonstration of European X-ray Free-Electron Laser beam quality
Author(s): F. Stephan et al.
The photoinjector test facility at DESY, Zeuthen site (PITZ), was built to develop and optimize photoelectron sources for superconducting linacs for high-brilliance, short-wavelength free-electron laser (FEL) applications like the free-electron laser in Hamburg (FLASH) and the European x-ray free-el...
[Phys. Rev. ST Accel. Beams 13, 020704] Published Tue Feb 23, 2010
- High field Q slope and the baking effect: Review of recent experimental results and new data on Nb heat treatments
Author(s): G. Ciovati, G. Myneni, F. Stevie, P. Maheshwari, and D. Griffis
The performance of superconducting radio-frequency (SRF) cavities made of bulk Nb at high fields (peak surface magnetic field greater than about 90 mT) is characterized by exponentially increasing rf losses (high-field Q slope), in the absence of field emission, which are often mitigated by low-tem...
[Phys. Rev. ST Accel. Beams 13, 022002] Published Mon Feb 22, 2010
- Kapitza resistance cooling of single crystal (111) niobium for superconducting rf cavities
Author(s): Jay Amrit and Claire Z. Antoine
The use of large grains or single crystal niobium to improve the Q factor of superconducting rf cavities for particle accelerators, is presently under study. Heat extraction which plays a decisive role in the thermomagnetic stability of these devices depends on the thermal conductivity of niobium K ...
[Phys. Rev. ST Accel. Beams 13, 023201] Published Thu Feb 18, 2010
- Transverse Schottky and beam transfer function measurements in space charge affected coasting ion beams
Author(s): Stefan Paret, Vladimir Kornilov, Oliver Boine-Frankenheim, and Thomas Weiland
Transverse Schottky spectra and beam transfer functions (BTFs) of coasting ion beams were measured in the heavy ion synchrotron SIS-18 in order to study the impact of space charge on the transverse beam dynamics. The particle number in the beam was varied to investigate the intensity dependence of t...
[Phys. Rev. ST Accel. Beams 13, 022802] Published Thu Feb 18, 2010
- Update on coaxial coupling scheme for International Linear Collider-type cavities
Author(s): P. Kneisel and J. Sekutowicz
This paper reports on our efforts to develop a flangeable coaxial coupler for both higher order mode and fundamental coupling for nine-cell ILC-type cavities, which were designed in the early 1990’s for pulsed operation with a duty factor less than 1%. The design of the coupler has been done in su...
[Phys. Rev. ST Accel. Beams 13, 022001] Published Wed Feb 17, 2010
- Measurements of the linac coherent light source laser heater and its impact on the x-ray free-electron laser performance
Author(s): Z. Huang, A. Brachmann, F.-J. Decker, Y. Ding, D. Dowell, P. Emma, J. Frisch, S. Gilevich, G. Hays, Ph. Hering, R. Iverson, H. Loos, A. Miahnahri, H.-D. Nuhn, D. Ratner, G. Stupakov, J. Turner, J. Welch, W. White, J. Wu, and D. Xiang
The very bright electron beam required for an x-ray free-electron laser (FEL), such as the linac coherent light source (LCLS), is susceptible to a microbunching instability in the magnetic bunch compressors, prior to the FEL undulator. The uncorrelated electron energy spread in the LCLS can be incre...
[Phys. Rev. ST Accel. Beams 13, 020703] Published Wed Feb 17, 2010
- Electro-optic sampling at 90 degree interaction geometry for time-of-arrival stamping of ultrafast relativistic electron diffraction
Author(s): C. M. Scoby, P. Musumeci, J. T. Moody, and M. S. Gutierrez
In this paper we study a new geometry setup for electro-optic sampling (EOS) where the electron beam runs parallel to the ⟨110⟩ face of a ZnTe crystal and the probe laser is perpendicular to it and to the beam path. The simple setup is used to encode the time-of-arrival information of a 3.5 â€...
[Phys. Rev. ST Accel. Beams 13, 022801] Published Tue Feb 16, 2010
- Algorithm for calculating spectral intensity due to charged particles in arbitrary motion
Author(s): A. G. R. Thomas
An algorithm for calculating the spectral intensity of radiation due to the coherent addition of many particles with arbitrary trajectories is described. Direct numerical integration of the Liénard-Wiechert potentials, in the far field, for extremely high photon energies and many particles is made ...
[Phys. Rev. ST Accel. Beams 13, 020702] Published Tue Feb 16, 2010
- Simulations of beam-beam effect in the presence of general chromaticity
Author(s): D. Zhou, K. Ohmi, Y. Seimiya, Y. Ohnishi, A. Morita, and H. Koiso
Optics parameters such as betatron tunes, beta functions, and dispersions depend on momentum deviation. Such dependence is characterized by general chromaticity. General chromaticity can induce emittance growth and luminosity degradation in colliders. To investigate the influence of general chromati...
[Phys. Rev. ST Accel. Beams 13, 021001] Published Wed Feb 03, 2010
- Small-signal theory of a grating-based free-electron laser in three dimensions
Author(s): J. D. Jarvis, H. L. Andrews, and C. A. Brau
We present an analytic theory for the small-signal operation of a grating-based free-electron laser that includes the effects of transverse diffraction on the evanescent wave. In this device, the electron beam interacts with an evanescent wave of the grating that bunches the beam and creates superra...
[Phys. Rev. ST Accel. Beams 13, 020701] Published Wed Feb 03, 2010
- “Robinson’s sum rule” revisited
Author(s): Yuri F. Orlov
This discussion revisits two articles on synchrotron radiation damping published in 1958, one by this author and Evgeny K. Tarasov [Zh. Eksp. Teor. Fiz. 34, 651 (1958); Sov. Phys. JETP 34, 449 (1958)], and one by Kenneth W. Robinson [Phys. Rev. 111, 373 (1958)]. The latter is the source of what is k...
[Phys. Rev. ST Accel. Beams 13, 024901] Published Tue Feb 02, 2010
- Three-dimensional electromagnetic model of the pulsed-power Z-pinch accelerator
Author(s): D. V. Rose, D. R. Welch, E. A. Madrid, C. L. Miller, R. E. Clark, W. A. Stygar, M. E. Savage, G. A. Rochau, J. E. Bailey, T. J. Nash, M. E. Sceiford, K. W. Struve, P. A. Corcoran, and B. A. Whitney
A three-dimensional, fully electromagnetic model of the principal pulsed-power components of the 26-MA ZR accelerator [D. H. McDaniel , in Proceedings of the 5th International Conference on Dense Z-Pinches (AIP, New York, 2002), p. 23] has been developed. This large-scale simulation model tracks ...
[Phys. Rev. ST Accel. Beams 13, 010402] Published Wed Jan 27, 2010
- Load-locked dc high voltage GaAs photogun with an inverted-geometry ceramic insulator
Author(s): P. A. Adderley, J. Clark, J. Grames, J. Hansknecht, K. Surles-Law, D. Machie, M. Poelker, M. L. Stutzman, and R. Suleiman
A new dc high voltage spin-polarized photoelectron gun has been constructed that employs a compact inverted-geometry ceramic insulator. Photogun performance at 100 kV bias voltage is summarized.
[Phys. Rev. ST Accel. Beams 13, 010101] Published Tue Jan 26, 2010
- Operation of a load current multiplier on a nanosecond mega-ampere pulse forming line generator
Author(s): A. S. Chuvatin, V. L. Kantsyrev, L. I. Rudakov, M. E. Cuneo, A. L. Astanovitskiy, R. Presura, A. S. Safronova, W. Cline, K. M. Williamson, I. Shrestha, G. C. Osborne, B. LeGalloudec, V. Nalajala, T. D. Pointon, and K. A. Mikkelson
We investigate the operation of a load current multiplier (LCM) on a pulse-forming-line nanosecond pulse-power generator. Potential benefits of using the LCM technique on such generators are studied analytically for a simplified case. A concrete LCM design on the Zebra accelerator (1.9 Ohm, ∼1 ...
[Phys. Rev. ST Accel. Beams 13, 010401] Published Mon Jan 25, 2010
- Matrix solution for the wall impedance of infinitely long multilayer circular beam tubes
Author(s): H. Hahn
The coupling impedance of beam tubes is a long-standing important topic for particle accelerators that many authors have addressed. The present study was initiated in view of a specific problem, but its novel approach is broadly applicable to the longitudinal and transverse coupling impedances of co...
[Phys. Rev. ST Accel. Beams 13, 012002] Published Thu Jan 21, 2010
- Suppression of microbunching instability with magnetic bunch length compression in a linac-based free electron laser
Author(s): S. Di Mitri, M. Cornacchia, S. Spampinati, and S. Milton
The aim of this paper is to investigate the effect of the magnetic bunch length compression on the development of the microbunching instability. It will be shown that, after removing the linear energy chirp required for the compression, an additional and properly tuned R_{56} transport matrix elemen...
[Phys. Rev. ST Accel. Beams 13, 010702] Published Wed Jan 20, 2010
- Beam simulations with initial bunch noise in superconducting rf proton linacs
Author(s): J. Tückmantel
Circular machines are plagued by coupled bunch instabilities (CBI), driven by impedance peaks, where then all cavity higher order modes (HOMs) are possible drivers. Limiting the CBI growth rate is the fundamental reason that all superconducting rf cavities in circular machines are equipped with HOM ...
[Phys. Rev. ST Accel. Beams 13, 011001] Published Tue Jan 19, 2010
- Laser assisted emittance exchange: Downsizing the x-ray free electron laser
Author(s): Dao Xiang
A technique is proposed to generate electron beam with ultralow transverse emittance through laser assisted transverse-to-longitudinal emittance exchange. In the scheme a laser operating in the TEM10 mode is used to interact with the electron beam in a dispersive region and to initiate the emittance...
[Phys. Rev. ST Accel. Beams 13, 010701] Published Tue Jan 12, 2010
- Overview of the Compact Linear Collider
Author(s): R. Tomás
The CLIC study is exploring the scheme for an electron-positron collider with a center-of-mass energy of 3 TeV in order to make the multi-TeV range accessible for lepton physics. The current goal of the project is to demonstrate the feasibility of the technology by the year 2010. Recently, importan...
[Phys. Rev. ST Accel. Beams 13, 014801] Published Mon Jan 11, 2010
- Novel superconducting rf structure for ampere-class beam current for multi-GeV energy recovery linacs
Author(s): Z. Liu and A. Nassiri
Future ampere-class energy recovery linacs (ERLs) based on superconducting technology demand efficient damping of the higher-order modes in the superconducting radio-frequency (SRF) accelerating structures to achieve stable beam operation in multipass, multibeam ERLs. We propose a new and novel SRF ...
[Phys. Rev. ST Accel. Beams 13, 012001] Published Wed Jan 06, 2010
- Rigorous evaluation of the edge-focusing wiggler based on the magnetic field measurement
Author(s): Shigeru Kashiwagi, Ryukou Kato, Akihito Mihara, Takanori Noda, Goro Isoyama, Kimichika Tsuchiya, Tatsuro Shioya, and Shigeru Yamamoto
The edge-focusing (EF) wiggler, which produces the strong field gradient for transverse focusing incorporated with the normal wiggler field, has been fabricated to evaluate its performance rigorously with the magnetic field measurement. It is a five-period planar wiggler with an edge angle of 2° an...
[Phys. Rev. ST Accel. Beams 12, 120703] Published Wed Dec 30, 2009
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