- Longitudinal-to-transverse mapping for femtosecond electron bunch length measurement
Author(s): Dao Xiang and Yuantao Ding
A longitudinal-to-transverse mapping technique is proposed to measure the length and temporal profile of ultrashort electron bunches. In this scheme a special chicane and a radio-frequency deflecting cavity are used to transform the beam’s longitudinal distribution into angular distribution which ...
[Phys. Rev. ST Accel. Beams 13, 094001] Published Wed Sep 01, 2010
- Nonlinear accelerator lattices with one and two analytic invariants
Author(s): V. Danilov and S. Nagaitsev
Integrable systems appeared in physics long ago at the onset of classical dynamics with examples being Kepler’s and other famous problems. Unfortunately, the majority of nonlinear problems turned out to be nonintegrable. In accelerator terms, any 2D nonlinear nonintegrable mapping produces chaotic...
[Phys. Rev. ST Accel. Beams 13, 084002] Published Wed Aug 25, 2010
- Evaluation of the diffusion coefficient of fluorine during the electropolishing of niobium
Author(s): Hui Tian and Charles E. Reece
Future accelerators require unprecedented cavity performance, which is strongly influenced by interior surface nanosmoothness. Electropolishing (EP) is the technique of choice being developed for high-field superconducting radio frequency (SRF) cavities. Previous study has shown that the mechanism o...
[Phys. Rev. ST Accel. Beams 13, 083502] Published Wed Aug 25, 2010
- New low inductance gas switches for linear transformer drivers
Author(s): J. R. Woodworth, W. A. Stygar, L. F. Bennett, M. G. Mazarakis, H. D. Anderson, M. J. Harden, J. R. Blickem, F. R. Gruner, and R. White
We have developed two new gas switches that are designed to be used with linear transformer drivers. The switches, which can be DC charged to 200 kV and triggered with less than a 2-ns 1-σ jitter, have overall inductances ranging from 69 to 85 nH. When transferring 400 J of energy per shot, the ...
[Phys. Rev. ST Accel. Beams 13, 080401] Published Wed Aug 25, 2010
- Monopole passband excitation by field emitters in 9-cell TESLA-type cavities
Author(s): V. Volkov, J. Knobloch, and A. Matveenko
We present an extension of the calculation of dipole-mode driven beam break-up instabilities, as calculated in [V. Volkov, Phys. Rev. ST Accel. Beams 12, 011301 (2009); V. Volkov, J. Knobloch, and A. Matveenko, Phys. Rev. ST Accel. Beams (to be published)], to the monopole fundamental mode passband....
[Phys. Rev. ST Accel. Beams 13, 084201] Published Thu Aug 19, 2010
- Three-dimensional simulation of harmonic up-conversion in a prebunched two-beam free-electron laser
Author(s): M. H. Rouhani and B. Maraghechi
Three-dimensional simulation of harmonic up-conversion in a free-electron laser amplifier operating simultaneously with two cold and relativistic electron beams with different energy is presented in the steady-state regime. The fundamental resonance of the higher energy beam is adjusted at the third...
[Phys. Rev. ST Accel. Beams 13, 080706] Published Wed Aug 18, 2010
- Beam transport line with scaling fixed field alternating gradient type magnets
Author(s): Shinji Machida and Richard Fenning
A scaling fixed field alternating gradient (FFAG) accelerator provides large momentum acceptance despite the fact that magnetic guiding fields are constant in time. Optical functions are identical over the large momentum range as well. We have designed a straight beam transport line (BTL) using a sc...
[Phys. Rev. ST Accel. Beams 13, 084001] Published Wed Aug 11, 2010
- Reliability and current-adaptability studies of a 352 MHz, 17 MeV, continuous-wave injector for an accelerator-driven system
Author(s): Chuan Zhang, Marco Busch, Horst Klein, Holger Podlech, Ulrich Ratzinger, Rudolf Tiede, and Jean-Luc Biarrotte
EUROTRANS is a European research program for the transmutation of high level nuclear waste in an accelerator-driven system (ADS). As proposed, the driver linac needs to deliver a 2.5–4 mA, 600 MeV continuous-wave (CW) proton beam and later a 20 mA, 800 MeV one to the spallation target in the p...
[Phys. Rev. ST Accel. Beams 13, 080101] Published Wed Aug 11, 2010
- Aging of the HF-H_{2} SO_{4} electrolyte used for the electropolishing of niobium superconducting radio frequency cavities: Origins and cure
Author(s): F. Eozénou, S. Berry, C. Antoine, Y. Gasser, J.-P. Charrier, and B. Malki
Electropolishing (EP) in the HF-H_{2} SO_{4} electrolyte is the most desirable surface treatment for niobium superconducting radio frequency cavities yet demonstrated, in terms of performance and surface finish. However, the efficiency of the electrolyte declines quickly with time (decrease in remov...
[Phys. Rev. ST Accel. Beams 13, 083501] Published Tue Aug 10, 2010
- Energy-z correlation measurements of electron bunches
Author(s): Stephen Molloy, Paul Emma, Josef Frisch, Rick Iverson, Marc Ross, Doug McCormick, Mike Woods, and Sean Walston
Bunch length and energy-z correlation measurements were performed on the high energy (28.5 GeV) electron test beam of the A-line and End Station A (ESA) facilities at the SLAC National Accelerator Laboratory. The longitudinal profile of each bunch was measured by imaging the synchrotron light emitt...
[Phys. Rev. ST Accel. Beams 13, 082802] Published Tue Aug 10, 2010
- 3 GHz digital rf control at the superconducting Darmstadt electron linear accelerator: First results from the baseband approach and extensions for other frequencies
Author(s): A. Araz, U. Bonnes, R. Eichhorn, F. Hug, M. Konrad, M. Platz, A. Richter, and R. Stassen
The low level rf system for the superconducting Darmstadt electron linear accelerator (S-DALINAC) developed 20 years ago and operating since converts the 3 GHz signals from the cavities down to the baseband and not to an intermediate frequency. While designing the new, digital rf control system th...
[Phys. Rev. ST Accel. Beams 13, 082801] Published Tue Aug 10, 2010
- Microbunch preserving bending system for a helical radiator at the European X-ray Free Electron Laser
Author(s): Y. Li, W. Decking, B. Faatz, and J. Pflueger
At the European X-ray Free Electron Laser there is a planar undulator system under construction called SASE3, which produces intense linearly polarized light in the wavelength range from 0.4–1.6 nm. Nevertheless there is a strong demand for circularly polarized radiation in this wavelength range....
[Phys. Rev. ST Accel. Beams 13, 080705] Published Tue Aug 10, 2010
- Emittance of a photocathode: Effects of temperature and field
Author(s): Kevin L. Jensen, P. G. O’Shea, and D. W. Feldman
The emittance of a photocathode is evaluated using a distribution function (“Moments”) approach to calculate the moments of the momentum. The effects of temperature and field, which affect the electron distribution and transmission probability, respectively, of electrons incident on the surface ...
[Phys. Rev. ST Accel. Beams 13, 080704] Published Thu Aug 05, 2010
- Dynamics of longitudinal phase-space modulations in an rf compressor for electron beams
Author(s): M. Venturini, M. Migliorati, C. Ronsivalle, M. Ferrario, and C. Vaccarezza
Free-electron lasers operating in the UV or x-ray radiation spectrum require peak beam currents that are generally higher than those obtainable by present electron sources, thus making bunch compression necessary. Compression, however, may heighten the effects of collective forces and degrade the be...
[Phys. Rev. ST Accel. Beams 13, 080703] Published Thu Aug 05, 2010
- Analysis and active compensation of microphonics in continuous wave narrow-bandwidth superconducting cavities
Author(s): A. Neumann, W. Anders, O. Kugeler, and J. Knobloch
Many proposals for next generation light sources based on single pass free electron lasers or energy recovery linac facilities require a continuous wave (cw) driven superconducting linac. The effective beam loading in such machines is very small and in principle the cavities can be operated at a ban...
[Phys. Rev. ST Accel. Beams 13, 082001] Published Wed Aug 04, 2010
- Nonlinear interaction of charged particles with strong laser pulses in a magnetic undulator
Author(s): H. K. Avetissian and Kh. V. Sedrakian
Laser acceleration due to the nonlinear-threshold phenomena of charged particle “reflection” and capture by slowed wave in a magnetic undulator is considered. The obtained numerical results prove the particle reflection and capture phenomena in the field of actual laser pulses with temporal and ...
[Phys. Rev. ST Accel. Beams 13, 081301] Published Wed Aug 04, 2010
- Electron beam energy spread measurements using optical klystron radiation
Author(s): B. Jia, J. Li, S. Huang, Scott C. Schmidler, and Y. K. Wu
In accelerators, the electron beam longitudinal dynamics critically depend on the energy distribution of the beam. Noninvasive, highly accurate measurement of the energy spread of the electron beam in the storage ring remains a challenge. Conventional techniques are limited to measuring a relatively...
[Phys. Rev. ST Accel. Beams 13, 080702] Published Wed Aug 04, 2010
- High-brilliance synchrotron radiation induced by the plasma magnetostatic mode
Author(s): F. Fiuza, L. O. Silva, and C. Joshi
Using multidimensional particle-in-cell simulations, we show that the magnetic undulator-type field of the plasma magnetostatic mode is indeed produced by the interaction of a laser pulse with a relativistic ionization front, as predicted by linear theory for a cold plasma. When the front with this ...
[Phys. Rev. ST Accel. Beams 13, 080701] Published Tue Aug 03, 2010
- Monte Carlo simulation of Touschek effect
Author(s): Aimin Xiao and Michael Borland
We present a Monte Carlo method implementation in the code elegant for simulating Touschek scattering effects in a linac beam. The local scattering rate and the distribution of scattered electrons can be obtained from the code either for a Gaussian-distributed beam or for a general beam whose distr...
[Phys. Rev. ST Accel. Beams 13, 074201] Published Fri Jul 30, 2010
- Measured and simulated transport of 1.9 MeV laser-accelerated proton bunches through an integrated test beam line at 1 Hz
Author(s): M. Nishiuchi et al.
A laser-driven repetition-rated 1.9 MeV proton beam line composed of permanent quadrupole magnets (PMQs), a radio frequency (rf) phase rotation cavity, and a tunable monochromator is developed to evaluate and to test the simulation of laser-accelerated proton beam transport through an integrated sy...
[Phys. Rev. ST Accel. Beams 13, 071304] Published Thu Jul 29, 2010
- Photoproduction of electron-positron pairs in bent single crystals
Author(s): Yu. A. Chesnokov, V. A. Maisheev, D. Bolognini, S. Hasan, M. Prest, and E. Vallazza
The process of photoproduction of electron-positron pairs in bent single crystals is considered. This consideration is based on the theory of coherent pairproduction in straight single crystals and take into account the linear polarization of the photon beam. In particular, it is shown that the prob...
[Phys. Rev. ST Accel. Beams 13, 070706] Published Thu Jul 29, 2010
- Residual activity induced by heavy ions and beam-loss criteria for heavy-ion accelerators
Author(s): I. Strašík, E. Mustafin, and M. Pavlovič
The paper presents results of FLUKA simulations of the residual activity induced by heavy ions in two target configurations representing: (1) a beam pipe of an accelerator and (2) a bulky accelerator structure like a magnet yoke or a coil. The target materials were stainless steel and copper repre...
[Phys. Rev. ST Accel. Beams 13, 071004] Published Wed Jul 28, 2010
- Smith-Purcell radiation from rough surfaces
Author(s): Zh. S. Gevorkian
Radiation of a charged particle moving parallel to an inhomogeneous surface is considered. Within a single formalism periodic and random gratings are examined. For the periodically inhomogeneous surface we derive new expressions for the dispersion relation and the spectral-angular intensity. In part...
[Phys. Rev. ST Accel. Beams 13, 070705] Published Wed Jul 28, 2010
- Characterization and applications of a tunable, laser-based, MeV-class Compton-scattering γ-ray source
Author(s): F. Albert, S. G. Anderson, D. J. Gibson, C. A. Hagmann, M. S. Johnson, M. Messerly, V. Semenov, M. Y. Shverdin, B. Rusnak, A. M. Tremaine, F. V. Hartemann, C. W. Siders, D. P. McNabb, and C. P. J. Barty
A high peak brilliance, laser-based Compton-scattering γ-ray source, capable of producing quasimonoenergetic photons with energies ranging from 0.1 to 0.9 MeV has been recently developed and used to perform nuclear resonance fluorescence (NRF) experiments. Techniques for characterization of γ-ray...
[Phys. Rev. ST Accel. Beams 13, 070704] Published Tue Jul 27, 2010
- Design and operation of a tunable MeV-level Compton-scattering-based γ-ray source
Author(s): D. J. Gibson, F. Albert, S. G. Anderson, S. M. Betts, M. J. Messerly, H. H. Phan, V. A. Semenov, M. Y. Shverdin, A. M. Tremaine, F. V. Hartemann, C. W. Siders, D. P. McNabb, and C. P. J. Barty
A monoenergetic gamma-ray (MEGa-ray) source based on Compton scattering, targeting nuclear physics applications such as nuclear resonance fluorescence, has been constructed and commissioned at Lawrence Livermore National Laboratory. In this paper, the overall architecture of the system, as well as s...
[Phys. Rev. ST Accel. Beams 13, 070703] Published Tue Jul 27, 2010
- Improving the output voltage waveform of an intense electron-beam accelerator based on helical type Blumlein pulse forming line
Author(s): Xin-Bing Cheng, Jin-Liang Liu, Hong-Bo Zhang, Jia-Huai Feng, and Bao-Liang Qian
The Blumlein pulse forming line (BPFL) consisting of an inner coaxial pulse forming line (PFL) and an outer coaxial PFL is widely used in the field of pulsed power, especially for intense electron-beam accelerators (IEBA). The output voltage waveform determines the quality and characteristics of the...
[Phys. Rev. ST Accel. Beams 13, 070402] Published Tue Jul 27, 2010
- Seismic response of linear accelerators
Author(s): C. Collette, K. Artoos, M. Guinchard, and C. Hauviller
This paper is divided into two parts. The first part presents recent measurements of ground motion in the LHC tunnel at CERN. From these measurements, an update of the ground motion model currently used in accelerator simulations is presented. It contains new features like a model of the lateral mot...
[Phys. Rev. ST Accel. Beams 13, 072801] Published Mon Jul 26, 2010
- High-gradient two-beam accelerator structure
Author(s): S. Yu Kazakov, S. V. Kuzikov, Y. Jiang, and J. L. Hirshfield
A novel cavity structure is described that could be the basis for a two-beam, high-gradient, accelerator. Versions of the structure could be used for acceleration of beams of electrons, positrons, muons, protons, or heavier ions; with either electron or proton drive beams. The structure embodies cav...
[Phys. Rev. ST Accel. Beams 13, 071303] Published Mon Jul 26, 2010
- Effective calculation of laser stripping via a broad shape resonance
Author(s): T. Gorlov and V. Danilov
This paper presents the theory and method of calculation of laser assisted charge exchange injection via a broad shape resonance of the hydrogen atom with a new level of accuracy. The method is optimized for fast calculations, needed for practical estimations of laser-stripping efficiency for charge...
[Phys. Rev. ST Accel. Beams 13, 074002] Published Fri Jul 23, 2010
- Effect of electron disruption in the energy recovery linac based electron ion collider
Author(s): Y. Hao and V. Ptitsyn
Beam-beam effects present one of the major factors limiting the luminosity of colliders. In the energy recovery linac (ERL) based eRHIC design, the electron beam, accelerated in a superconducting ERL, collides with the proton beam circulating in the RHIC ring. During such collisions the electron bea...
[Phys. Rev. ST Accel. Beams 13, 071003] Published Mon Jul 19, 2010
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