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Preview: Recent Articles in Phys. Rev. ST Accel. Beams

Recent Articles in Phys. Rev. Accel. Beams

Recent articles in Physical Review Accelerators and Beams

Published: 2017-02-21T16:25:56-05:00


Modeling power flow in the induction cavity with a two dimensional circuit simulation


Author(s): Fan Guo, Wenkang Zou, Boyi Gong, Jihao Jiang, Lin Chen, Meng Wang, and Weiping Xie
We have proposed a two dimensional (2D) circuit model of induction cavity. The oil elbow and azimuthal transmission line are modeled with one dimensional transmission line elements, while 2D transmission line elements are employed to represent the regions inward the azimuthal transmission line. The …
[Phys. Rev. Accel. Beams 20, 020401] Published Tue Feb 21, 2017

Continuously tunable narrowband pulses in the THz gap from laser-modulated electron bunches in a storage ring


Author(s): P. Ungelenk, M. Höner, H. Huck, S. Khan, C. Mai, A. Meyer auf der Heide, C. Evain, C. Szwaj, and S. Bielawski
This article reports on the generation of narrowband coherent synchrotron radiation from an electron storage ring. For the first time, this kind of radiation was now produced with continuously tunable frequencies in the so-called “THz gap” (between 1.2 and 5.6 THz), whereas previous experiments were…
[Phys. Rev. Accel. Beams 20, 020706] Published Tue Feb 21, 2017

Normal planar undulators doubling as transverse gradient undulators


Author(s): Qika Jia and Heting Li

Sending the beam off center through a planar undulator allows lasing at larger energy spread, and may enable compact free electron lasers based on laser-plasma acceleration.

[Phys. Rev. Accel. Beams 20, 020707] Published Tue Feb 21, 2017

Electron lenses for head-on beam-beam compensation in RHIC


Author(s): X. Gu et al.
Two electron lenses (e-lenses) have been in operation during the 2015 RHIC physics run as part of a head-on beam-beam compensation scheme. While the RHIC lattice was chosen to reduce the beam-beam-induced resonance-driving terms, the electron lenses reduced the beam-beam-induced tune spread. This ha…
[Phys. Rev. Accel. Beams 20, 023501] Published Fri Feb 17, 2017

Compression of a photoinjector electron bunch in the negative-mass undulator


Author(s): Ilya V. Bandurkin, Ilya S. Kurakin, and Andrey V. Savilov

An electron bunch is compressed in the THz region using a negative mass undulator against Coulomb repulsion.

[Phys. Rev. Accel. Beams 20, 020704] Published Wed Feb 15, 2017

First operation of a harmonic lasing self-seeded free electron laser


Author(s): E. A. Schneidmiller, B. Faatz, M. Kuhlmann, J. Rönsch-Schulenburg, S. Schreiber, M. Tischer, and M. V. Yurkov

First experimental observation of harmonic lasing self-seeded free electron laser demonstrates shorter saturation length, narrower bandwidth, and improved taper efficiency.

[Phys. Rev. Accel. Beams 20, 020705] Published Wed Feb 15, 2017

Monochromaticity of coherent Smith-Purcell radiation from finite size grating


Author(s): A. Aryshev, A. Potylitsyn, G. Naumenko, M. Shevelev, K. Lekomtsev, L. Sukhikh, P. Karataev, Y. Honda, N. Terunuma, and J. Urakawa
Investigation of coherent Smith-Purcell radiation (SPR) spectral characteristics was performed both experimentally and by numerical simulation. The measurement of SPR spectral line shapes of different diffraction orders was carried out at the KEK LUCX facility. A pair of room-temperature Schottky ba…
[Phys. Rev. Accel. Beams 20, 024701] Published Mon Feb 13, 2017

Depth-of-field effects in wiggler radiation sources: Geometrical versus wave optics


Author(s): Richard P. Walker
A detailed analysis is carried out of the optical properties of synchrotron radiation emitted by multipole wigglers, concentrating on the effective source size and brightness and the so-called “depth of field” effects, concerning which there has been some controversy in the literature. By comparing …
[Phys. Rev. Accel. Beams 20, 020703] Published Wed Feb 08, 2017

Phase matching strategy for the undulator system in the European X-ray Free Electron Laser


Author(s): Yuhui Li and Joachim Pflueger
The undulator system in the European X-ray Free Electron Laser is mainly comprised of 5-m long undulator segments and 1.1 m long intersections in between. The longitudinal component of the electrons’ velocity is reduced when traveling inside an undulator due to the wiggle motion. Therefore the optic…
[Phys. Rev. Accel. Beams 20, 020702] Published Mon Feb 06, 2017

Editorial: From the APS Editor in Chief


Author(s): Pierre Meystre
[Phys. Rev. Accel. Beams 20, 020001] Published Fri Feb 03, 2017

Compact beam transport system for free-electron lasers driven by a laser plasma accelerator


Author(s): Tao Liu, Tong Zhang, Dong Wang, and Zhirong Huang
Utilizing laser-driven plasma accelerators (LPAs) as a high-quality electron beam source is a promising approach to significantly downsize the x-ray free-electron laser (XFEL) facility. A multi-GeV LPA beam can be generated in several-centimeter acceleration distance, with a high peak current and a …
[Phys. Rev. Accel. Beams 20, 020701] Published Wed Feb 01, 2017

New target solution for a muon collider or a muon-decay neutrino beam facility: The granular waterfall target


Author(s): Han-Jie Cai, Guanghui Yang, Nikos Vassilopoulos, Sheng Zhang, Fen Fu, Ye Yuan, and Lei Yang
A new target solution, the granular waterfall target, is proposed here for a muon collider or a muon-decay neutrino beam facility, especially for the moment which adopts a 15 MW continuous-wave (cw) superconducting linac. Compared to the mercury jet target, the granular waterfall target works by a m…
[Phys. Rev. Accel. Beams 20, 023401] Published Wed Feb 01, 2017

Machine detector interface studies: Layout and synchrotron radiation estimate in the future circular collider interaction region


Author(s): Manuela Boscolo, Helmut Burkhardt, and Michael Sullivan
The interaction region layout for the e^{+}e^{−} future circular collider FCC-ee is presented together with a preliminary estimate of synchrotron radiation that affects this region. We describe in this paper the main guidelines of this design and the estimate of synchrotron radiation coming from the…
[Phys. Rev. Accel. Beams 20, 011008] Published Fri Jan 27, 2017

Numerical simulations of gas mixing effect in electron cyclotron resonance ion sources


Author(s): V. Mironov, S. Bogomolov, A. Bondarchenko, A. Efremov, and V. Loginov
The particle-in-cell Monte Carlo collisions code nam-ecris is used to simulate the electron cyclotron resonance ion source (ECRIS) plasma sustained in a mixture of Kr with O_{2}, N_{2}, Ar, Ne, and He. The model assumes that ions are electrostatically confined in the ECR zone by a dip in the plasma …
[Phys. Rev. Accel. Beams 20, 013402] Published Thu Jan 26, 2017

Statistics of vacuum breakdown in the high-gradient and low-rate regime


Author(s): Walter Wuensch, Alberto Degiovanni, Sergio Calatroni, Anders Korsbäck, Flyura Djurabekova, Robin Rajamäki, and Jorge Giner-Navarro
In an increasing number of high-gradient linear accelerator applications, accelerating structures must operate with both high surface electric fields and low breakdown rates. Understanding the statistical properties of breakdown occurrence in such a regime is of practical importance for optimizing a…
[Phys. Rev. Accel. Beams 20, 011007] Published Wed Jan 25, 2017

Experimental study of current loss and plasma formation in the Z machine post-hole convolute


Author(s): M. R. Gomez, R. M. Gilgenbach, M. E. Cuneo, C. A. Jennings, R. D. McBride, E. M. Waisman, B. T. Hutsel, W. A. Stygar, D. V. Rose, and Y. Maron

Spectroscopic measurements of plasma density, temperature, and plasma closure velocities are preparing the path to scaled-up pulsed power drivers for future research.

[Phys. Rev. Accel. Beams 20, 010401] Published Tue Jan 24, 2017

On-line dispersion estimation and correction scheme for the Compact Linear Collider


Author(s): J. Pfingstner, E. Adli, and D. Schulte
The Compact Linear Collider (CLIC) has stringent component alignment tolerances in order to preserve the ultralow emittance of the utilized particle beams. Beam-based alignment techniques have been designed to relax these tolerances to realizable values. In this paper, a scheme is presented that is …
[Phys. Rev. Accel. Beams 20, 011006] Published Tue Jan 24, 2017

Generating high-brightness and coherent soft x-ray pulses in the water window with a seeded free-electron laser


Author(s): Kaishang Zhou, Chao Feng, Haixiao Deng, and Dong Wang
We propose a new scheme to generate high-brightness and temporal coherent soft x-ray radiation in a seeded free-electron laser. The proposed scheme is based on the coherent harmonic generation (CHG) and superradiant principles. A CHG scheme is first used to generate a coherent signal at ultrahigh ha…
[Phys. Rev. Accel. Beams 20, 010702] Published Mon Jan 23, 2017

Symplectic multiparticle tracking model for self-consistent space-charge simulation


Author(s): Ji Qiang
Symplectic tracking is important in accelerator beam dynamics simulation. So far, to the best of our knowledge, there is no self-consistent symplectic space-charge tracking model available in the accelerator community. In this paper, we present a two-dimensional and a three-dimensional symplectic mu…
[Phys. Rev. Accel. Beams 20, 014203] Published Mon Jan 23, 2017

Vertically polarizing undulator with dynamic compensation of magnetic forces


Author(s): N. Strelnikov, I. Vasserman, J. Xu, D. Jensen, O. Schmidt, E. Trakhtenberg, K. Suthar, E. R. Moog, G. Pile, and E. Gluskin
As part of the R program of the LCLS-II project, a novel 3.4-meter-long undulator prototype with horizontal magnetic field and dynamic force compensation has recently been developed at the Advanced Photon Source (APS). Previous steps in this development were the shorter 0.8-meter-long and 2.8-meter-…
[Phys. Rev. Accel. Beams 20, 010701] Published Fri Jan 20, 2017

Accuracy and feasibility of the β^{*} measurement for LHC and High Luminosity LHC using k modulation


Author(s): F. Carlier and R. Tomás
The future regimes of operation of the LHC will require improved control of β^{*} measurements to successfully level the luminosities in the interaction points. The method of k modulation has been widely used in other machines to measure lattice beta functions. In the LHC, k modulation of the closes…
[Phys. Rev. Accel. Beams 20, 011005] Published Fri Jan 20, 2017

Fundamental cavity impedance and longitudinal coupled-bunch instabilities at the High Luminosity Large Hadron Collider


Author(s): P. Baudrenghien and T. Mastoridis
The interaction between beam dynamics and the radio frequency (rf) station in circular colliders is complex and can lead to longitudinal coupled-bunch instabilities at high beam currents. The excitation of the cavity higher order modes is traditionally damped using passive devices. But the wakefield…
[Phys. Rev. Accel. Beams 20, 011004] Published Thu Jan 19, 2017

Trace-space reconstruction of low-emittance electron beams through betatron radiation in laser-plasma accelerators


Author(s): A. Curcio, M. Anania, F. Bisesto, E. Chiadroni, A. Cianchi, M. Ferrario, F. Filippi, D. Giulietti, A. Marocchino, M. Petrarca, V. Shpakov, and A. Zigler
A new methodology able to model and reconstruct the transverse trace space of low-emittance electron beams accelerated in the bubble regime of laser-plasma interaction is presented. The single-shot measurement of both the electron energy spectrum and the betatron radiation spectrum is shown to allow…
[Phys. Rev. Accel. Beams 20, 012801] Published Tue Jan 17, 2017

Impedance simulations and measurements on the LHC collimators with embedded beam position monitors


Author(s): N. Biancacci, F. Caspers, J. Kuczerowski, E. Métral, N. Mounet, B. Salvant, A. Mostacci, O. Frasciello, and M. Zobov
The LHC collimation system is a critical element for the safe operation of the LHC machine. The necessity of fast accurate positioning of the collimator’s jaws, recently introduced the need to have button beam position monitors directly embedded in the jaws extremities of the LHC tertiary collimator…
[Phys. Rev. Accel. Beams 20, 011003] Published Thu Jan 12, 2017

Electromagnetic characterization of nonevaporable getter properties between 220–330 and 500–750 GHz for the Compact Linear Collider damping rings


Author(s): E. Koukovini-Platia, G. Rumolo, and C. Zannini
Due to its effective pumping ability, nonevaporable getter (NEG) coating is considered for the vacuum chambers of the Compact Linear Collider (CLIC) electron damping rings (EDR). The aim is to suppress fast beam ion instabilities. The electromagnetic (EM) characterization of the NEG properties up to…
[Phys. Rev. Accel. Beams 20, 011002] Published Wed Jan 11, 2017

Emittance compensation in split photoinjectors


Author(s): Klaus Floettmann

An alternative approach to emittance compensation presenting a better understanding of the injector optimization.

[Phys. Rev. Accel. Beams 20, 013401] Published Wed Jan 11, 2017

Parametric instabilities in 3D periodically focused beams with space charge


Author(s): Ingo Hofmann and Oliver Boine-Frankenheim
Parametric resonances of beam eigenmodes with a periodic focusing system under the effect of space charge—also called structural instabilities—are the collective counterparts to parametric resonances of single particles or of mechanical systems. Their common feature is that an exponential instabilit…
[Phys. Rev. Accel. Beams 20, 014202] Published Wed Jan 11, 2017

Diffusion measurement from observed transverse beam echoes


Author(s): Tanaji Sen and Wolfram Fischer
We study the measurement of transverse diffusion through beam echoes. We revisit earlier observations of echoes in the Relativistic Heavy Ion Collider and apply an updated theoretical model to these measurements. We consider three possible models for the diffusion coefficient and show that only one …
[Phys. Rev. Accel. Beams 20, 011001] Published Mon Jan 09, 2017

Design and testing of a four rod crab cavity for High Luminosity LHC


Author(s): B. Hall, G. Burt, R. Apsimon, C. J. Lingwood, A. Tutte, A. Grudiev, A. Macpherson, M. Navarro-Tapia, R. Calaga, K. G. Hernández-Chahín, R. B. Appleby, and P. Goudket
A 4-rod deflecting structure is proposed as a possible crab cavity design for the LHC high luminosity upgrade. Crab cavities are required for the LHC luminosity upgrade to provide a greater bunch overlap in the presence of a crossing angle, but must fit in the existing limited space. The structure h…
[Phys. Rev. Accel. Beams 20, 012001] Published Tue Jan 03, 2017

Operational performance of the CERN injector complex with transversely split beams


Author(s): S. Abernethy, A. Akroh, H. Bartosik, A. Blas, T. Bohl, S. Cettour-Cave, K. Cornelis, H. Damerau, S. Gilardoni, M. Giovannozzi, C. Hernalsteens, A. Huschauer, V. Kain, D. Manglunki, G. Métral, B. Mikulec, B. Salvant, J.-L. Sanchez Alvarez, R. Steerenberg, G. Sterbini, and Y. Wu

Multiturn extraction scheme is now used in standard operation for manipulating high-intensity proton beams at the CERN Proton Synchrotron.

[Phys. Rev. Accel. Beams 20, 014001] Published Tue Jan 03, 2017

Higher order mode beams mitigate halos in high intensity proton linacs


Author(s): Abhishek Pathak and Srinivas Krishnagopal
High intensity proton linacs (HIPLs) for applications such as Accelerator Driven Reactor Systems (ADRS) have serious beam dynamics issues related to beam halo formation. This can lead to particle loss and radioactivation of the surroundings which consequently limit the beam current. Beam halos are l…
[Phys. Rev. Accel. Beams 20, 014201] Published Tue Jan 03, 2017

Fokker-Planck analysis of transverse collective instabilities in electron storage rings


Author(s): Ryan R. Lindberg
We analyze single bunch transverse instabilities due to wakefields using a Fokker-Planck model. We first expand on the work of T. Suzuki, Part. Accel. 12, 237 (1982) to derive the theoretical model including chromaticity, both dipolar and quadrupolar transverse wakefields, and the effects of damping…
[Phys. Rev. Accel. Beams 19, 124402] Published Fri Dec 30, 2016

Multiple harmonic frequencies resonant cavity design and half-scale prototype measurements for a fast kicker


Author(s): Yulu Huang, Haipeng Wang, Robert A. Rimmer, Shaoheng Wang, and Jiquan Guo

A multiple harmonic deflecting cavity for use as a fast kicker has been designed and a prototype demonstrated.

[Phys. Rev. Accel. Beams 19, 122001] Published Thu Dec 29, 2016

Laser-driven ion accelerators for tumor therapy revisited


Author(s): Ute Linz and Jose Alonso
Ten years ago, the authors of this report published a first paper on the technical challenges that laser accelerators need to overcome before they could be applied to tumor therapy. Among the major issues were the maximum energy of the accelerated ions and their intensity, control and reproducibilit…
[Phys. Rev. Accel. Beams 19, 124802] Published Thu Dec 29, 2016

Final focus designs for crab waist colliders


Author(s): A. Bogomyagkov, E. Levichev, and P. Piminov
The crab waist collision scheme promises significant luminosity gain. The successful upgrade of the DAΦNE collider proved the principle of crab waist collision and increased luminosity 3 times. Therefore, several new projects try to implement the scheme. The paper reviews interaction region designs …
[Phys. Rev. Accel. Beams 19, 121005] Published Wed Dec 28, 2016

CERN Proton Synchrotron booster space charge simulations with a realistic model for alignment and field errorsn1


Author(s): V. Forte, E. Benedetto, and M. McAteer
The CERN Proton Synchrotron booster (PSB) is one of the machines of the LHC injector chain which will be upgraded within the LHC Injectors Upgrade (LIU) project. The injection energy of the PSB will be increased to 160 MeV in order to mitigate direct space charge effects, considered to be the main p…
[Phys. Rev. Accel. Beams 19, 124202] Published Wed Dec 28, 2016

Continuous wave superconducting radio frequency electron linac for nuclear physics research


Author(s): Charles E. Reece
CEBAF, the Continuous Electron Beam Accelerator Facility, has been actively serving the nuclear physics research community as a unique forefront international resource since 1995. This cw electron linear accelerator (linac) at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Fac…
[Phys. Rev. Accel. Beams 19, 124801] Published Wed Dec 28, 2016

Beam commissioning for a superconducting proton linac


Author(s): Zhi-Jun Wang, Yuan He, Huan Jia, Wei-ping Dou, Wei-long Chen, X. L. Zhang, Shu-hui Liu, Chi Feng, Yue Tao, Wang-sheng Wang, Jian-qiang Wu, Sheng-hu Zhang, and Hong-Wei Zhao
To develop the next generation of safe and cleaner nuclear energy, the accelerator-driven subcritical (ADS) system emerges as one of the most attractive technologies. It will be able to transmute the long-lived transuranic radionuclides produced in the reactors of today’s nuclear power plants into s…
[Phys. Rev. Accel. Beams 19, 120101] Published Tue Dec 27, 2016

Availability modeling approach for future circular colliders based on the LHC operation experience


Author(s): Arto Niemi, Andrea Apollonio, Johannes Gutleber, Peter Sollander, Jussi-Pekka Penttinen, and Seppo Virtanen
Reaching the challenging integrated luminosity production goals of a future circular hadron collider (FCC-hh) and high luminosity LHC (HL-LHC) requires a thorough understanding of today’s most powerful high energy physics research infrastructure, the LHC accelerator complex at CERN. FCC-hh, a 4 time…
[Phys. Rev. Accel. Beams 19, 121003] Published Tue Dec 27, 2016

Volume reflection and channeling of ultrarelativistic protons in germanium bent single crystals


Author(s): S. Bellucci and V. A. Maisheev
The paper is devoted to the investigation of volume reflection and channeling processes of ultrarelativistic positive charged particles moving in germanium single crystals. We demonstrate that the choice of atomic potential on the basis of the Hartree-Fock method and the correct choice of the Debye …
[Phys. Rev. Accel. Beams 19, 121004] Published Tue Dec 27, 2016

Transverse beam profile reconstruction using synchrotron radiation interferometry


Author(s): L. Torino and U. Iriso
Transverse beam size measurements in new generation of synchrotron light sources is a challenging task due to their characteristic small beam emittances and low couplings. Since the late 1990s, synchrotron radiation interferometry (SRI) has been used in many accelerators to measure the beam size thr…
[Phys. Rev. Accel. Beams 19, 122801] Published Tue Dec 27, 2016

Early transverse decoherence of bunches with space charge


Author(s): Ivan Karpov, Vladimir Kornilov, and Oliver Boine-Frankenheim

An analytical model, particle tracking simulations, and beam measurements all reveal how space-charge forces counteract the beam decoherence.

[Phys. Rev. Accel. Beams 19, 124201] Published Tue Dec 27, 2016

Longitudinal transport measurements in an energy recovery accelerator with triple bend achromat arcs


Author(s): F. Jackson, D. Angal-Kalinin, Y. M. Saveliev, P. H. Williams, and A. Wolski
Longitudinal properties of electron bunches (energy spread and bunch length) and their manipulation are of importance in free electron lasers (FELs), where magnetic bunch length compression is a common feature of beam transport. Recirculating accelerators and energy recovery linac accelerators (ERLs…
[Phys. Rev. Accel. Beams 19, 120701] Published Fri Dec 23, 2016

Hybrid high gradient permanent magnet quadrupole


Author(s): P. N’gotta, G. Le Bec, and J. Chavanne
This paper presents an innovative compact permanent magnet quadrupole with a strong gradient for potential use in future light source lattices. Its magnetic structure includes simple mechanical parts, rectangular permanent magnet blocks and soft iron poles. It has a wide aperture in the horizontal p…
[Phys. Rev. Accel. Beams 19, 122401] Published Tue Dec 20, 2016

Local transverse coupling impedance measurements in a synchrotron light source from turn-by-turn acquisitions


Author(s): Michele Carlà, Gabriele Benedetti, Thomas Günzel, Ubaldo Iriso, and Zeus Martí
Transverse beam coupling impedance is a source of beam instabilities that limits the machine performance in circular accelerators. Several beam based techniques have been used to measure the transverse impedance of an accelerator, usually based on the optics distortion produced by the impedance sour…
[Phys. Rev. Accel. Beams 19, 121002] Published Mon Dec 19, 2016

Investigating the performances of a 1 MV high pulsed power linear transformer driver: from beam dynamics to x radiation


Author(s): R. Maisonny, M. Ribière, M. Toury, J. M. Plewa, M. Caron, G. Auriel, and T. d’Almeida
The performance of a 1 MV pulsed high-power linear transformer driver accelerator were extensively investigated based on a numerical approach which utilizes both electromagnetic and Monte Carlo simulations. Particle-in-cell calculations were employed to examine the beam dynamics throughout the magne…
[Phys. Rev. Accel. Beams 19, 120401] Published Fri Dec 16, 2016

First commissioning of the SuperKEKB vacuum system


Author(s): Y. Suetsugu, K. Shibata, T. Ishibashi, K. Kanazawa, M. Shirai, S. Terui, and H. Hisamatsu
The first (Phase-1) commissioning of SuperKEKB, an asymmetric-energy electron-positron collider at KEK, began in February 2016, after more than five years of upgradation work on KEKB and successfully ended in June 2016. A major task of the Phase-1 commissioning was the vacuum scrubbing of new beam p…
[Phys. Rev. Accel. Beams 19, 121001] Published Fri Dec 16, 2016

Perturbation-minimized triangular bunch for high-transformer ratio using a double dogleg emittance exchange beam line


Author(s): G. Ha, M. H. Cho, W. Gai, K.-J. Kim, W. Namkung, and J. G. Power
The longitudinal shape, i.e., the current profile, of an electron bunch determines the transformer ratio in a collinear wakefield accelerator and thus methods are sought to control the longitudinal bunch shape. The emittance exchange (EEX) appears to be promising for creating a precisely controlled …
[Phys. Rev. Accel. Beams 19, 121301] Published Fri Dec 16, 2016

Laser pulsing in linear Compton scattering


Author(s): G. A. Krafft, E. Johnson, K. Deitrick, B. Terzić, R. Kelmar, T. Hodges, W. Melnitchouk, and J. R. Delayen
Previous work on calculating energy spectra from Compton scattering events has either neglected considering the pulsed structure of the incident laser beam, or has calculated these effects in an approximate way subject to criticism. In this paper, this problem has been reconsidered within a linear p…
[Phys. Rev. Accel. Beams 19, 121302] Published Fri Dec 16, 2016

Transverse coupled-bunch instability thresholds in the presence of a harmonic-cavity-flattened rf potential


Author(s): F. J. Cullinan, R. Nagaoka, G. Skripka, and P. F. Tavares
A small vacuum chamber aperture is a present trend in the design of future synchrotron light sources. This leads to a large resistive-wall impedance that can drive coupled-bunch instabilities. Another trend is the use of passively driven cavities at a harmonic of the main radio frequency to lengthen…
[Phys. Rev. Accel. Beams 19, 124401] Published Fri Dec 16, 2016

rf breakdown measurements in electron beam driven 200 GHz copper and copper-silver accelerating structures


Author(s): Massimo Dal Forno, Valery Dolgashev, Gordon Bowden, Christine Clarke, Mark Hogan, Doug McCormick, Alexander Novokhatski, Brendan O’Shea, Bruno Spataro, Stephen Weathersby, and Sami G. Tantawi
This paper explores the physics of vacuum rf breakdowns in subterahertz high-gradient traveling-wave accelerating structures. We present the experimental results of rf tests of 200 GHz metallic accelerating structures, made of copper and copper-silver. These experiments were carried out at the Facil…
[Phys. Rev. Accel. Beams 19, 111301] Published Wed Nov 30, 2016

Characterization and long term operation of a novel superconducting undulator with 15 mm period length in a synchrotron light source


Author(s): S. Casalbuoni, A. Cecilia, S. Gerstl, N. Glamann, A. W. Grau, T. Holubek, C. Meuter, D. Saez de Jauregui, R. Voutta, C. Boffo, Th. Gerhard, M. Turenne, and W. Walter
A new cryogen-free full scale (1.5 m long) superconducting undulator with a period length of 15 mm (SCU15) has been successfully tested in the ANKA storage ring. This represents a very important milestone in the development of superconducting undulators for third and fourth generation light sources …
[Phys. Rev. Accel. Beams 19, 110702] Published Mon Nov 28, 2016

Analytical approach to chromatic correction in the final focus system of circular colliders


Author(s): Yunhai Cai
A conventional final focus system in particle accelerators is systematically analyzed. We find simple relations between the parameters of two focus modules in the final telescope. Using the relations, we derive the chromatic Courant-Snyder parameters for the telescope. The parameters are scaled appr…
[Phys. Rev. Accel. Beams 19, 111006] Published Mon Nov 28, 2016

Linear microbunching analysis for recirculation machines


Author(s): C.-Y. Tsai, D. Douglas, R. Li, and C. Tennant
Microbunching instability (MBI) has been one of the most challenging issues in designs of magnetic chicanes for short-wavelength free-electron lasers or linear colliders, as well as those of transport lines for recirculating or energy-recovery-linac machines. To quantify MBI for a recirculating mach…
[Phys. Rev. Accel. Beams 19, 114401] Published Mon Nov 28, 2016

Fast mapping of terahertz bursting thresholds and characteristics at synchrotron light sources


Author(s): Miriam Brosi, Johannes L. Steinmann, Edmund Blomley, Erik Bründermann, Michele Caselle, Nicole Hiller, Benjamin Kehrer, Yves-Laurent Mathis, Michael J. Nasse, Lorenzo Rota, Manuel Schedler, Patrik Schönfeldt, Marcel Schuh, Markus Schwarz, Marc Weber, and Anke-Susanne Müller

Bunch-by-bunch fast measurement of microbunching instability is done by detecting coherent THz radiation.

[Phys. Rev. Accel. Beams 19, 110701] Published Tue Nov 22, 2016

Off-axis beam dynamics in rf-gun-based electron photoinjectors


Author(s): R. Huang, C. Mitchell, C. Papadopoulos, H. Qian, M. Venturini, J. Qiang, D. Filippetto, J. Staples, Q. Jia, and F. Sannibale
The need to operate an rf-gun-based electron photoinjector with a beam emitted away from the cathode center can occur under various circumstances. First, in some cases the cathode can be affected by ion back-bombardment that progressively reduces the quantum efficiency (QE) in its center, making off…
[Phys. Rev. Accel. Beams 19, 113401] Published Tue Nov 22, 2016

Evaluation of the radiation field in the future circular collider detector


Author(s): M. I. Besana, F. Cerutti, A. Ferrari, W. Riegler, and V. Vlachoudis
The radiation load on a detector at a 100 TeV proton-proton collider, that is being investigated within the future circular collider (FCC) study, is presented. A first concept of the detector has been modeled and relevant fluence and dose distributions have been calculated using the fluka Monte Carl…
[Phys. Rev. Accel. Beams 19, 111004] Published Mon Nov 21, 2016

Design of beam optics for the future circular collider e^{+} e^{−} collider rings


Author(s): K. Oide et al.
A beam optics scheme has been designed for the future circular collider-e^{+}e^{−} (FCC-ee). The main characteristics of the design are: beam energy 45 to 175 GeV, 100 km circumference with two interaction points (IPs) per ring, horizontal crossing angle of 30 mrad at the IP and the crab-waist schem…
[Phys. Rev. Accel. Beams 19, 111005] Published Mon Nov 21, 2016

Erratum: Particle-in-cell simulation of x-ray wakefield acceleration and betatron radiation in nanotubes [Phys. Rev. Accel. Beams 19, 101004 (2016)]


Author(s): Xiaomei Zhang, Toshiki Tajima, Deano Farinella, Youngmin Shin, Gerard Mourou, Jonathan Wheeler, Peter Taborek, Pisin Chen, Franklin Dollar, and Baifei Shen
[Phys. Rev. Accel. Beams 19, 119902] Published Mon Nov 21, 2016

Niobium superconducting rf cavity fabrication by electrohydraulic forming


Author(s): E. Cantergiani, S. Atieh, F. Léaux, A. T. Perez Fontenla, S. Prunet, L. Dufay-Chanat, T. Koettig, F. Bertinelli, O. Capatina, G. Favre, F. Gerigk, A. C. Jeanson, J. Fuzeau, G. Avrillaud, D. Alleman, J. Bonafe, and P. Marty
Superconducting rf (SRF) cavities are traditionally fabricated from superconducting material sheets or made of copper coated with superconducting material, followed by trim machining and electron-beam welding. An alternative technique to traditional shaping methods, such as deep-drawing and spinning…
[Phys. Rev. Accel. Beams 19, 114703] Published Thu Nov 17, 2016

Iron-free detector magnet options for the future circular collider


Author(s): Matthias Mentink, Alexey Dudarev, Helder Filipe Pais Da Silva, Gabriella Rolando, Benoit Cure, Andrea Gaddi, Vyacheslav Klyukhin, Hubert Gerwig, Udo Wagner, and Herman ten Kate
In this paper, several iron-free solenoid-based designs of a detector magnet for the future circular collider for hadron-hadron collisions (FCC-hh) are presented. The detector magnet designs for FCC-hh aim to provide bending power for particles over a wide pseudorapidity range (0≤|η|≤4). To achieve …
[Phys. Rev. Accel. Beams 19, 111001] Published Wed Nov 16, 2016

Radiation damage and thermal shock response of carbon-fiber-reinforced materials to intense high-energy proton beams


Author(s): N. Simos, Z. Zhong, S. Ghose, H. G. Kirk, L-P Trung, K. T. McDonald, Z. Kotsina, P. Nocera, R. Assmann, S. Redaelli, A. Bertarelli, E. Quaranta, A. Rossi, R. Zwaska, K. Ammigan, P. Hurh, and N. Mokhov
A comprehensive study on the effects of energetic protons on carbon-fiber composites and compounds under consideration for use as low-Z pion production targets in future high-power accelerators and low-impedance collimating elements for intercepting TeV-level protons at the Large Hadron Collider has…
[Phys. Rev. Accel. Beams 19, 111002] Published Wed Nov 16, 2016

Design and optimization of Compact Linear Collider main linac accelerating structure


Author(s): Hao Zha and Alexej Grudiev
The Compact Linear Collider (CLIC) main linac uses waveguide damped structure as its baseline design. The current baseline structure design written in the CLIC Conceptual Design Report is named “CLIC-G.” Recent activities on the CLIC-G design including high power tests on structure prototypes and th…
[Phys. Rev. Accel. Beams 19, 111003] Published Wed Nov 16, 2016

Dynamics of electron injection and acceleration driven by laser wakefield in tailored density profiles


Author(s): P. Lee, G. Maynard, T. L. Audet, B. Cros, R. Lehe, and J.-L. Vay
The dynamics of electron acceleration driven by laser wakefield is studied in detail using the particle-in-cell code WARP with the objective to generate high-quality electron bunches with narrow energy spread and small emittance, relevant for the electron injector of a multistage accelerator. Simula…
[Phys. Rev. Accel. Beams 19, 112802] Published Wed Nov 16, 2016

Narrow-band photon beam via laser Compton scattering in an energy recovery linac


Author(s): T. Akagi, A. Kosuge, S. Araki, R. Hajima, Y. Honda, T. Miyajima, M. Mori, R. Nagai, N. Nakamura, M. Shimada, T. Shizuma, N. Terunuma, and J. Urakawa

The first experimental demonstration of Compton (Thomson) radiation with an energy recovery linac in combination with a laser enhancement cavity.

[Phys. Rev. Accel. Beams 19, 114701] Published Tue Nov 15, 2016

Influence of the electron beam emittance on the polarization of a laser-electron x-ray generator


Author(s): R. M. Feshchenko, A. V. Vinogradov, and I. A. Artyukov
In this paper we analyze the polarization of the x-ray radiation coming from laser-electron x-ray generator (LEXG). We obtain general relations connecting the polarization state of outgoing x-ray radiation to the polarization state of laser beam as well as to the parameters of electron beam. We demo…
[Phys. Rev. Accel. Beams 19, 114702] Published Mon Nov 14, 2016

Publisher’s Note: Experimental measurements and theoretical model of the cryogenic performance of bialkali photocathode and characterization with Monte Carlo simulation [Phys. Rev. Accel. Beams 19, 103401 (2016)]


Author(s): Huamu Xie, Ilan Ben-Zvi, Triveni Rao, Tianmu Xin, and Erdong Wang
[Phys. Rev. Accel. Beams 19, 119901] Published Mon Nov 14, 2016

Formation region effects in transition radiation, bremsstrahlung, and ionization loss of ultrarelativistic electrons


Author(s): S. V. Trofymenko and N. F. Shul’ga
The processes of transition radiation and bremsstrahlung by an ultrarelativistic electron as well as the effect of transition radiation influence upon the electron ionization loss in thin layer of substance are theoretically investigated in the case when radiation formation region has macroscopicall…
[Phys. Rev. Accel. Beams 19, 112801] Published Thu Nov 03, 2016

Efficient twin aperture magnets for the future circular e^{+} /e^{_} collider


Author(s): A. Milanese
We report preliminary designs for the arc dipoles and quadrupoles of the FCC-ee double-ring collider. After recalling cross sections and parameters of warm magnets used in previous large accelerators, we focus on twin aperture layouts, with a magnetic coupling between the gaps, which minimizes const…
[Phys. Rev. Accel. Beams 19, 112401] Published Wed Nov 02, 2016

Double stop-band structure near half-integer tunes in high-intensity rings


Author(s): K. Moriya, M. Ota, K. Fukushima, M. Yamaguchi, K. Ito, and H. Okamoto

Experiments at a table-top ion trap reveal space-charge driven coherent betatron resonances which will occur in high-intensity storage rings.

[Phys. Rev. Accel. Beams 19, 114201] Published Wed Nov 02, 2016

Beam shaping to improve the free-electron laser performance at the Linac Coherent Light Source


Author(s): Y. Ding, K. L. F. Bane, W. Colocho, F.-J. Decker, P. Emma, J. Frisch, M. W. Guetg, Z. Huang, R. Iverson, J. Krzywinski, H. Loos, A. Lutman, T. J. Maxwell, H.-D. Nuhn, D. Ratner, J. Turner, J. Welch, and F. Zhou
A new operating mode has been developed for the Linac Coherent Light Source (LCLS) in which we shape the longitudinal phase space of the electron beam. This mode of operation is realized using a horizontal collimator located in the middle of the first bunch compressor to truncate the head and tail o…
[Phys. Rev. Accel. Beams 19, 100703] Published Thu Oct 27, 2016

Volume reflection angle study as a function of crystal curvature


Author(s): V. M. Biryukov
We compare the volume reflection angles measured for protons and electrons over a wide energy range from 1 to 400 GeV in Si and Ge bent crystals at PNPI, IHEP, SLAC, and CERN with the predictions of FLUX and CATCH simulation codes based on binary collisions (FLUX) and continuum model (CATCH). We sho…
[Phys. Rev. Accel. Beams 19, 101006] Published Thu Oct 27, 2016

Caustic-based approach to understanding bunching dynamics and current spike formation in particle bunches


Author(s): T. K. Charles, D. M. Paganin, and R. T. Dowd
Current modulations, current spikes, and current horns, are observed in a range of accelerator physics applications including strong bunch compression in Free Electron Lasers and linear colliders, trains of microbunching for terahertz radiation, microbunching instability and many others. This paper …
[Phys. Rev. Accel. Beams 19, 104402] Published Thu Oct 27, 2016

Commissioning experience and beam physics measurements at the SwissFEL Injector Test Facility


Author(s): T. Schietinger et al.

This paper describes their facility and its operating parameters, the results of commissioning, and demonstration of innovative diagnostics.

[Phys. Rev. Accel. Beams 19, 100702] Published Wed Oct 26, 2016

Extreme regimes of femtosecond photoemission from a copper cathode in a dc electron gun


Author(s): P. L. E. M. Pasmans, D. C. van Vugt, J. P. van Lieshout, G. J. H. Brussaard, and O. J. Luiten
The femtosecond photoemission yield from a copper cathode and the emittance of the created electron beams has been studied in a 12  MeV/m, 100 keV dc electron gun over a wide range of laser fluence, from the linear photoemission regime until the onset of image charge limitations and cathode damaging…
[Phys. Rev. Accel. Beams 19, 103403] Published Wed Oct 26, 2016

Enhanced dynamical stability with harmonic slip stacking


Author(s): Jeffrey Eldred and Robert Zwaska
We develop a configuration of radio-frequency (rf) cavities to dramatically improve the performance of slip stacking. Slip stacking is an accumulation technique used at Fermilab to nearly double proton intensity by maintaining two beams of different momenta in the same storage ring. The two particle…
[Phys. Rev. Accel. Beams 19, 104001] Published Wed Oct 26, 2016

Limitation on the accelerating gradient of a wakefield excited by an ultrarelativistic electron beam in rubidium plasma


Author(s): N. Vafaei-Najafabadi, K. A. Marsh, C. E. Clayton, W. An, W. B. Mori, C. Joshi, W. Lu, E. Adli, S. Corde, C. I. Clarke, M. Litos, S. Z. Green, S. Gessner, J. Frederico, A. S. Fisher, Z. Wu, D. Walz, and M. J. Hogan
We have investigated the viability of using plasmas formed by ionization of high Z, low ionization potential element rubidium (Rb) for beam-driven plasma wakefield acceleration. The Rb vapor column confined by argon (Ar) buffer gas was used to reduce the expected limitation on the beam propagation l…
[Phys. Rev. Accel. Beams 19, 101303] Published Tue Oct 25, 2016

Systematical study on superconducting radio frequency elliptic cavity shapes applicable to future high energy accelerators and energy recovery linacs


Author(s): Valery Shemelin, Shahnam Gorgi Zadeh, Johann Heller, and Ursula van Rienen
Elliptic cavities at medium- and high-β range are receiving broader use in the particle accelerator applications. Optimizing the shape of these cavities is a complex and demanding process. In this paper we propose an optimization approach to minimize the ratio of peak magnetic field to the accelerat…
[Phys. Rev. Accel. Beams 19, 102002] Published Tue Oct 25, 2016

Low-frequency quadrupole impedance of undulators and wigglers


Author(s): A. Blednykh, G. Bassi, Y. Hidaka, V. Smaluk, and G. Stupakov
An analytical expression of the low-frequency quadrupole impedance for undulators and wigglers is derived and benchmarked against beam-based impedance measurements done at the 3 GeV NSLS-II storage ring. The adopted theoretical model, valid for an arbitrary number of electromagnetic layers with para…
[Phys. Rev. Accel. Beams 19, 104401] Published Tue Oct 25, 2016

Investigation of beam self-polarization in the future e^{+} e^{−} circular collider


Author(s): E. Gianfelice-Wendt
The use of resonant depolarization has been suggested for precise beam energy measurements (better than 100 keV) in the e^{+}e^{−} Future Circular Collider (FCC-e^{+}e^{−}) for Z and WW physics at 45 and 80 GeV beam energy respectively. Longitudinal beam polarization would benefit the Z peak physics…
[Phys. Rev. Accel. Beams 19, 101005] Published Mon Oct 24, 2016

Effects of ion bombardment on bulk GaAs photocathodes with different surface-cleavage planes


Author(s): Wei Liu, Shukui Zhang, Marcy Stutzman, and Matt Poelker

Photocathodes with (110) cleave plane are shown to be the least susceptible to ion damage. The observed susceptibility is explained by enhanced ion channeling.

[Phys. Rev. Accel. Beams 19, 103402] Published Mon Oct 24, 2016

Experimental measurements and theoretical model of the cryogenic performance of bialkali photocathode and characterization with Monte Carlo simulation


Author(s): Huamu Xie, Ilan Ben-Zvi, Triveni Rao, Tianmu Xin, and Erdong Wang
High-average-current, high-brightness electron sources have important applications, such as in high-repetition-rate free-electron lasers, or in the electron cooling of hadrons. Bialkali photocathodes are promising high-quantum-efficiency (QE) cathode materials, while superconducting rf (SRF) electro…
[Phys. Rev. Accel. Beams 19, 103401] Published Wed Oct 19, 2016

Particle-in-cell simulation of x-ray wakefield acceleration and betatron radiation in nanotubes


Author(s): Xiaomei Zhang, Toshiki Tajima, Deano Farinella, Youngmin Shin, Gerard Mourou, Jonathan Wheeler, Peter Taborek, Pisin Chen, Franklin Dollar, and Baifei Shen
Though wakefield acceleration in crystal channels has been previously proposed, x-ray wakefield acceleration has only recently become a realistic possibility since the invention of the single-cycled optical laser compression technique. We investigate the acceleration due to a wakefield induced by a …
[Phys. Rev. Accel. Beams 19, 101004] Published Tue Oct 18, 2016

Long term dynamics of the high luminosity Large Hadron Collider with crab cavities


Author(s): J. Barranco García, R. De Maria, A. Grudiev, R. Tomás García, R. B. Appleby, and D. R. Brett
The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) aims to achieve an integrated luminosity of 200–300  fb^{−1} per year, including the contribution from the upgrade of the injector chain. For the HL-LHC the larger crossing angle together with a smaller beta function at the collision …
[Phys. Rev. Accel. Beams 19, 101003] Published Tue Oct 11, 2016

Polarization response of RHIC electron lens lattices


Author(s): V. H. Ranjbar, F. Méot, M. Bai, D. T. Abell, and D. Meiser
Depolarization response for a system of two orthogonal snakes at irrational tunes is studied in depth using lattice independent spin integration. In particular we consider the effect of overlapping spin resonances in this system, to understand the impact of phase, tune, relative location and thresho…
[Phys. Rev. Accel. Beams 19, 101002] Published Mon Oct 10, 2016

Tunable THz radiation source from dielectric loaded waveguide excited by nonrelativistic electron bunch trains


Author(s): Weiwei Li, Zhigang He, Yalin Lu, Ruixuan Huang, Weihao Liu, Qika Jia, and Lin Wang
We propose a novel scheme to generate a tunable narrow-band THz radiation. In this scheme, a train of laser pulses with THz repetition rate is used to drive a photocathode direct current (DC) gun, leading to the emission of a train of electron bunches. The electron bunch train is subsequently accele…
[Phys. Rev. Accel. Beams 19, 104701] Published Thu Oct 06, 2016

Probing half β_{y}^{*} optics in the Accelerator Test Facility 2


Author(s): M. Patecki, D. Bett, E. Marin, F. Plassard, R. Tomás, K. Kubo, S. Kuroda, T. Naito, T. Okugi, T. Tauchi, and N. Terunuma
A nanometer beam size at the interaction point (IP) is required for future linear colliders to achieve the desired rate of particle collisions. KEK Accelerator Test Facility 2 (ATF2), a scaled down implementation of the linear collider beam delivery system, serves for demonstrating the feasibility o…
[Phys. Rev. Accel. Beams 19, 101001] Published Wed Oct 05, 2016

Wake excited in plasma by an ultrarelativistic pointlike bunch


Author(s): G. Stupakov, B. Breizman, V. Khudik, and G. Shvets
We study propagation of a relativistic electron bunch through a cold plasma assuming that the transverse and longitudinal dimensions of the bunch are much smaller than the plasma collisionless skin depth. Treating the bunch as a point charge and assuming that its charge is small, we derive a simplif…
[Phys. Rev. Accel. Beams 19, 101302] Published Wed Oct 05, 2016

Breakdown study based on direct in situ observation of inner surfaces of an rf accelerating cavity during a high-gradient test


Author(s): Tetsuo Abe, Tatsuya Kageyama, Hiroshi Sakai, Yasunao Takeuchi, and Kazuo Yoshino
We have developed normal-conducting accelerating single-cell cavities with a complete higher-order-mode (HOM) heavily damped structure, into which we feed a 508.9-MHz continuous wave. During a high-gradient test of the second production version of the cavity, we performed a breakdown study based on …
[Phys. Rev. Accel. Beams 19, 102001] Published Tue Oct 04, 2016

Transverse to longitudinal phase space coupling in an electron beam for suppression of microbunching instability


Author(s): Dazhang Huang, Chao Feng, Haixiao Deng, Qiang Gu, and Zhentang Zhao
The microbunching instability developed during the beam compression process in the linear accelerator (LINAC) of a free-electron laser (FEL) facility has always been a problem that degrades the lasing performance, and even no FEL is able to be produced if the beam quality is destroyed too much by th…
[Phys. Rev. Accel. Beams 19, 100701] Published Mon Oct 03, 2016

Electron acceleration and generation of high-brilliance x-ray radiation in kilojoule, subpicosecond laser-plasma interactions


Author(s): J. Ferri, X. Davoine, S. Y. Kalmykov, and A. Lifschitz

Comparison through particle-in-cell simulations of self-modulated-high-density and resonant-low-density regimes provides a bridge between the laser-wakefield-acceleration and picosecond-petawatt-laser communities.

[Phys. Rev. Accel. Beams 19, 101301] Published Mon Oct 03, 2016

Efficient computation of coherent synchrotron radiation in a rectangular chamber


Author(s): Robert L. Warnock and David A. Bizzozero
We study coherent synchrotron radiation (CSR) in a perfectly conducting vacuum chamber of rectangular cross section, in a formalism allowing an arbitrary sequence of bends and straight sections. We apply the paraxial method in the frequency domain, with a Fourier development in the vertical coordina…
[Phys. Rev. Accel. Beams 19, 090705] Published Tue Sep 27, 2016

Performance analysis of superconducting rf cavities for the CERN rare isotope accelerator


Author(s): S. Calatroni, A. Miyazaki, G. Rosaz, A. Sublet, W. Venturini Delsolaro, R. Vaglio, and V. Palmieri
The first cryomodule of the new HIE-ISOLDE rare isotope accelerator has recently been commissioned with beam at CERN, with the second cryomodule ready for installation. Each cryomodule contains five superconducting low-beta quarter wave cavities, produced with the technology of sputtering a thin nio…
[Phys. Rev. Accel. Beams 19, 092002] Published Fri Sep 23, 2016

Multiobjective optimizations of a novel cryocooled dc gun based ultrafast electron diffraction beam line


Author(s): Colwyn Gulliford, Adam Bartnik, and Ivan Bazarov
We present the results of multiobjective genetic algorithm optimizations of a single-shot ultrafast electron diffraction beam line utilizing a 225 kV dc gun with a novel cryocooled photocathode system and buncher cavity. Optimizations of the transverse projected emittance as a function of bunch char…
[Phys. Rev. Accel. Beams 19, 093402] Published Fri Sep 23, 2016

Electron bunch structure in energy recovery linac with high-voltage dc photoelectron gun


Author(s): Y. M. Saveliev, F. Jackson, J. K. Jones, and J. W. McKenzie
The internal structure of electron bunches generated in an injector line with a dc photoelectron gun is investigated. Experiments were conducted on the ALICE (accelerators and lasers in combined experiments) energy recovery linac at Daresbury Laboratory. At a relatively low dc gun voltage of 230 kV,…
[Phys. Rev. Accel. Beams 19, 094002] Published Fri Sep 23, 2016

Longitudinal stability in multiharmonic standing wave linacs


Author(s): L. R. Carver, R. M. Jones, Y. Jiang, and J. L. Hirshfield
Accelerating cavities that excite multiple modes at integer harmonics of the fundamental frequency have the potential to be used to suppress the onset of rf breakdown and reduce the pulsed surface heating at high accelerating gradients. Understanding the effect of an additional harmonic cavity mode …
[Phys. Rev. Accel. Beams 19, 094001] Published Thu Sep 22, 2016

Utilizing the N beam position monitor method for turn-by-turn optics measurements


Author(s): A. Langner, G. Benedetti, M. Carlà, U. Iriso, Z. Martí, J. Coello de Portugal, and R. Tomás
The N beam position monitor method (N-BPM) which was recently developed for the LHC has significantly improved the precision of optics measurements that are based on BPM turn-by-turn data. The main improvement is due to the consideration of correlations for statistical and systematic error sources, …
[Phys. Rev. Accel. Beams 19, 092803] Published Wed Sep 21, 2016

Radiation emitted by transverse-gradient undulators


Author(s): Axel Bernhard, Nils Braun, Verónica Afonso Rodríguez, Peter Peiffer, Robert Rossmanith, Christina Widmann, and Michael Scheer
Conventional undulators are used in synchrotron light sources to produce radiation with a narrow relative spectral width as compared to bending magnets or wigglers. The spectral width of the radiation produced by conventional undulators is determined by the number of undulator periods and by the ene…
[Phys. Rev. Accel. Beams 19, 090704] Published Tue Sep 20, 2016

Factors affecting the output pulse flatness of the linear transformer driver cavity systems with 5th harmonics


Author(s): V. M. Alexeenko, M. G. Mazarakis, A. A. Kim, S. S. Kondratiev, V. A. Sinebryukhov, S. N. Volkov, M. E. Cuneo, M. L. Kiefer, J. J. Leckby, B. V. Oliver, and P. D. Maloney
We describe the study we have undertaken to evaluate the effect of component tolerances in obtaining a voltage output flat top for a linear transformer driver (LTD) cavity containing 3rd and 5th harmonic bricks [A. A. Kim et al., in Proc. IEEE Pulsed Power and Plasma Science PPPS2013 (San Francisco…
[Phys. Rev. Accel. Beams 19, 090401] Published Mon Sep 19, 2016

Design and experimental tests of free electron laser wire scanners


Author(s): G. L. Orlandi, P. Heimgartner, R. Ischebeck, C. Ozkan Loch, S. Trovati, P. Valitutti, V. Schlott, M. Ferianis, and G. Penco
SwissFEL is a x-rays free electron laser (FEL) driven by a 5.8 GeV linac under construction at Paul Scherrer Institut. In SwissFEL, wire scanners (WSCs) will be complementary to view-screens for emittance measurements and routinely used to monitor the transverse profile of the electron beam during F…
[Phys. Rev. Accel. Beams 19, 092802] Published Fri Sep 16, 2016