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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: 2018-03-19T09:04:17+00:00


Field of first magnetic flux entry and pinning strength of superconductors for rf application measured with muon spin rotation


Author(s): T. Junginger, S. H. Abidi, R. D. Maffett, T. Buck, M. H. Dehn, S. Gheidi, R. Kiefl, P. Kolb, D. Storey, E. Thoeng, W. Wasserman, and R. E. Laxdal

The performance of superconducting radiofrequency (SRF) cavities used for particle accelerators depends on two characteristic material parameters: field of first flux entry ${H}_{\text{entry}}$ and pinning strength. The former sets the limit for the maximum achievable accelerating gradient, while th...

[Phys. Rev. Accel. Beams 21, 032002] Published Fri Mar 16, 2018

Real-time cavity simulator-based low-level radio-frequency test bench and applications for accelerators


Author(s): Feng Qiu, Shinichiro Michizono, Takako Miura, Toshihiro Matsumoto, Na Liu, and Sigit Basuki Wibowo

A Low-level radio-frequency (LLRF) control systems is required to regulate the rf field in the rf cavity used for beam acceleration. As the LLRF system is usually complex, testing of the basic functions or control algorithms of this system in real time and in advance of beam commissioning is strongl...

[Phys. Rev. Accel. Beams 21, 032003] Published Fri Mar 16, 2018

Cross-wake force and correlated head-tail instability in beam-beam collisions with a large crossing angle


Author(s): Nami Kuroo, Kazuhito Ohmi, Katsunobu Oide, Demin Zhou, and Frank Zimmermann

This paper discusses novel coherent beam-beam instability in collisions with a large crossing angle. The instability appears in the correlated head-tail motion of two colliding beams. A cross-wake force, which is localized at the collision point, is introduced to represent the head-tail correlation ...

[Phys. Rev. Accel. Beams 21, 031002] Published Thu Mar 15, 2018

Radiation of a charge flying in a partially loaded dielectric section of a waveguide


Author(s): Aleksandra A. Grigoreva, Andrey V. Tyukhtin, Viktor V. Vorobev, Sergey N. Galyamin, and Sergey Antipov

We consider the electromagnetic field of a point charged particle moving along the axis of a cylindrical waveguide from a homogeneously filled area to a dielectric loading area having an axially symmetrical channel. We are interested in studying the Cherenkov radiation excited in the bilayer area. T...

[Phys. Rev. Accel. Beams 21, 031302] Published Mon Mar 12, 2018

Emittance growth due to space charge compensation and beam intensity instabilities in negative ion beams


Author(s): C. A. Valerio-Lizarraga

The need to extract the maximum beam intensity with low transversal emittance often comes with the drawback of operating the ion source to limits where beam current instabilities arise, such fluctuations can change the beam properties producing a mismatch in the following sections of the machine. Th...

[Phys. Rev. Accel. Beams 21, 030101] Published Thu Mar 08, 2018

Effect of low temperature baking in nitrogen on the performance of a niobium superconducting radio frequency cavity


Author(s): Pashupati Dhakal, Santosh Chetri, Shreyas Balachandran, Peter J. Lee, and Gianluigi Ciovati

We report the rf performance of a single cell superconducting radiofrequency cavity after low temperature baking in a nitrogen environment. A significant increase in quality factor has been observed when the cavity was heat treated in the temperature range of $120–160\text{ }°\mathrm{C}$ with a nitr...

[Phys. Rev. Accel. Beams 21, 032001] Published Thu Mar 08, 2018

Simulation of inverse Compton scattering and its implications on the scattered linewidth


Author(s): N. Ranjan, B. Terzić, G. A. Krafft, V. Petrillo, I. Drebot, and L. Serafini

Rising interest in inverse Compton sources has increased the need for efficient models that properly quantify the behavior of scattered radiation given a set of interaction parameters. The current state-of-the-art simulations rely on Monte Carlo–based methods, which, while properly expressing scatte...

[Phys. Rev. Accel. Beams 21, 030701] Published Tue Mar 06, 2018

Thermostructural characterization and structural elastic property optimization of novel high luminosity LHC collimation materials at CERN


Author(s): M. Borg, A. Bertarelli, F. Carra, P. Gradassi, J. Guardia-Valenzuela, M. Guinchard, G. Arnau Izquierdo, P. Mollicone, O. Sacristan-de-Frutos, and N. Sammut

The CERN Large Hadron Collider is currently being upgraded to operate at a stored beam energy of 680 MJ through the High Luminosity upgrade. The LHC performance is dependent on the functionality of beam collimation systems, essential for safe beam cleaning and machine protection. A dedicated beam ex...

[Phys. Rev. Accel. Beams 21, 031001] Published Mon Mar 05, 2018

Stability condition for the drive bunch in a collinear wakefield accelerator


Author(s): S. S. Baturin and A. Zholents

The beam breakup instability of the drive bunch in the structure-based collinear wakefield accelerator is considered and a stabilizing method is proposed. The method includes using the specially designed beam focusing channel, applying the energy chirp along the electron bunch, and keeping energy ch...

[Phys. Rev. Accel. Beams 21, 031301] Published Mon Mar 05, 2018

Feasibility of diffraction radiation for noninvasive beam diagnostics as characterized in a storage ring


Author(s): L. Bobb, R. Kieffer, T. Lefevre, S. Mazzoni, T. Aumeyr, P. Karataev, M. Billing, J. Conway, and J. Shanks

In recent years, there has been an increasing demand for noninvasive beam size monitoring on particle accelerators. Ideally, these monitors should be cost effective and require little or no maintenance. These monitors should also be suitable for both linear and circular machines. Here, the experimen...

[Phys. Rev. Accel. Beams 21, 032801] Published Mon Mar 05, 2018

First heavy ion beam tests with a superconducting multigap CH cavity


Author(s): W. Barth, K. Aulenbacher, M. Basten, M. Busch, F. Dziuba, V. Gettmann, M. Heilmann, T. Kürzeder, M. Miski-Oglu, H. Podlech, A. Rubin, A. Schnase, M. Schwarz, and S. Yaramyshev

Very compact accelerating-focusing structures, as well as short focusing periods, high accelerating gradients and short drift spaces are strongly required for superconducting (sc) accelerator sections operating at low and medium energies for continuous wave (cw) heavy ion beams. To keep the GSI-supe...

[Phys. Rev. Accel. Beams 21, 020102] Published Tue Feb 27, 2018

Theoretical analysis and simulation study of the deep overcompression mode of velocity bunching for a comblike electron bunch train


Author(s): Dan Wang, Lixin Yan, YingChao Du, Wenhui Huang, Wei Gai, and Chuanxiang Tang

Premodulated comblike electron bunch trains are used in a wide range of research fields, such as for wakefield-based particle acceleration and tunable radiation sources. We propose an optimized compression scheme for bunch trains in which a traveling wave accelerator tube and a downstream drift segm...

[Phys. Rev. Accel. Beams 21, 024403] Published Tue Feb 27, 2018

Comment on “Collision monochromatization in ${e}^{+}{e}^{−}$ colliders”


Author(s): D. Shatilov

Bogomyagkov and Levichev [Phys. Rev. Accel. Beams 20, 051001 (2017)] have recently reported on monochromatization in collision schemes with crossing angle. From their results, in particular, it may seem that: (1) horizontal dispersion at the IP can provide monochromatization factor $\mathrm{Λ}≫1$ wh...

[Phys. Rev. Accel. Beams 21, 028001] Published Mon Feb 26, 2018

Erratum: Collision monochromatization in ${e}^{+}{e}^{−}$ colliders [Phys. Rev. Accel. Beams 20, 051001 (2017)]


Author(s): A. Bogomyagkov and E. Levichev
[Phys. Rev. Accel. Beams 21, 029902] Published Mon Feb 26, 2018

Nonlinear theory of transverse beam echoes


Author(s): Tanaji Sen and Yuan Shen Li

Transverse beam echoes can be excited with a single dipole kick followed by a single quadrupole kick. They have been used to measure diffusion in hadron beams and have other diagnostic capabilities. Here we develop theories of the transverse echo nonlinear in both the dipole and quadrupole kick stre...

[Phys. Rev. Accel. Beams 21, 021002] Published Fri Feb 23, 2018

Development of a hybrid mode linear transformer driver stage


Author(s): Le Zhang, Meng Wang, Liangji Zhou, Qing Tian, Fan Guo, Lingyun Wang, Yanling Qing, Yue Zhao, Yingmin Dai, Wenhui Han, Lin Chen, and Weiping Xie

At present, the mainstream technologies of primary power sources of large pulse power devices adopt Marx or linear transformer driver (LTD) designs. Based on the analysis of the characteristics of these two types of circuit topologies, the concept of a hybrid mode LTD stage based on Marx branches is...

[Phys. Rev. Accel. Beams 21, 020401] Published Wed Feb 21, 2018

Low energy dark current collimation system in single-pass linacs


Author(s): S. Bettoni, P. Craievich, M. Pedrozzi, M. Schaer, and L. Stingelin

The dark current emitted from a surface of a radio frequency cavity may be a severe issue for the activation and the protection of the components of linear accelerators, if this current is lost in an uncontrolled manner. For a single-pass linac based on a photo-injector, we studied the possibility o...

[Phys. Rev. Accel. Beams 21, 023401] Published Wed Feb 21, 2018

Structure resonances due to space charge in periodic focusing channels


Author(s): Chao Li and R. A. Jameson

The Vlasov-Poisson model is one of the most effective methods to study the space charge dominated beam evolution self-consistently in a periodic focusing channel. Since the approach to get the solution with this model is not trivial, previous studies are limited in degenerated conditions, either in ...

[Phys. Rev. Accel. Beams 21, 024204] Published Wed Feb 21, 2018

Examining mitigation schemes for synchrotron radiation in high-energy hadron colliders


Author(s): G. Guillermo, D. Sagan, and F. Zimmermann

At high proton-beam energies, beam-induced synchrotron radiation is an important source of heating, of beam-related vacuum pressure increase, and of primary photoelectrons, which can give rise to an electron cloud. We use the synrad3d code developed at Cornell to simulate the photon distributions in...

[Phys. Rev. Accel. Beams 21, 021001] Published Wed Feb 14, 2018

Simulation, measurement, and mitigation of beam instability caused by the kicker impedance in the 3-GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex


Author(s): P. K. Saha, Y. Shobuda, H. Hotchi, H. Harada, N. Hayashi, M. Kinsho, F. Tamura, N. Tani, M. Yamamoto, Y. Watanabe, Yong Ho Chin, and J. A Holmes

The transverse impedance of eight extraction pulsed kicker magnets is a strong beam instability source in the 3-GeV rapid cycling synchrotron (RCS) at the Japan Proton Accelerator Research Complex. Significant beam instability occurs even at half of the designed 1 MW beam power when the chromaticity...

[Phys. Rev. Accel. Beams 21, 024203] Published Wed Feb 14, 2018

Harmonic cavities and the transverse mode-coupling instability driven by a resistive wall


Author(s): M. Venturini

Investigation of the transverse mode-coupling instability in the presence of harmonic cavity and resistive wall impedance.

[Phys. Rev. Accel. Beams 21, 024402] Published Wed Feb 14, 2018

Publisher’s Note: High efficiency tapered free-electron lasers with a prebunched electron beam [Phys. Rev. Accel. Beams 20, 110701 (2017)]


Author(s): C. Emma, N. Sudar, P. Musumeci, A. Urbanowicz, and C. Pellegrini
[Phys. Rev. Accel. Beams 21, 029901] Published Tue Feb 13, 2018

New halo formation mechanism at the KEK compact energy recovery linac


Author(s): Olga Tanaka, Norio Nakamura (中村 典雄), Miho Shimada (島田 美帆), Tsukasa Miyajima (宮島 司), Akira Ueda (上田 明), Takashi Obina (帯名 崇), and Ryota Takai (高井 良太)

The beam halo mitigation is a very important challenge for reliable and safe operation of a high-energy machine. A systematic beam halo study was conducted at the KEK compact energy recovery linac (cERL) since non-negligible beam loss was observed in the recirculation loop during a common operation....

[Phys. Rev. Accel. Beams 21, 024202] Published Mon Feb 12, 2018

Generation of coherent two-color pulses at two adjacent harmonics in a seeded free-electron laser


Author(s): Zhouyu Zhao, Heting Li, and Qika Jia

The growing requirements of pump-probe techniques and nonlinear optics experiments greatly promote the studies of two-color free-electron lasers (FELs). We propose a new method to generate coherent two-color pulses in a high-gain harmonic generation (HGHG) FEL. In this scheme, an initial tilted elec...

[Phys. Rev. Accel. Beams 21, 020701] Published Fri Feb 09, 2018

Conceptual design of a compact high gradient quadrupole magnet of varying strength using permanent magnets


Author(s): Gautam Sinha

A concept is presented to design magnets using cylindrical-shaped permanent-magnet blocks, where various types of magnetic fields can be produced by either rotating or varying the size of the magnetic blocks within a given mechanical structure. A general method is introduced to calculate the 3D magn...

[Phys. Rev. Accel. Beams 21, 022401] Published Fri Feb 09, 2018

Use of a corrugated beam pipe as a passive deflector for bunch length measurements


Author(s): Jimin Seok, Moses Chung, Heung-Sik Kang, Chang-Ki Min, and Donghyun Na

We report the experimental demonstration of bunch length measurements using a corrugated metallic beam pipe as a passive deflector. The corrugated beam pipe has been adopted for reducing longitudinal chirping after the bunch compressors in several XFEL facilities worldwide. In the meantime, there ha...

[Phys. Rev. Accel. Beams 21, 022801] Published Fri Feb 09, 2018

Connection between zero chromaticity and long in-plane polarization lifetime in a magnetic storage ring


Author(s): G. Guidoboni et al. (JEDI Collaboration)

Polarization lifetime of a hadron beam can be maximized by tuning the storage-ring sextupoles, thereby meeting a key requirement for future electric-dipole-moment experiments.

[Phys. Rev. Accel. Beams 21, 024201] Published Wed Feb 07, 2018

Low emittance growth in a low energy beam transport line with un-neutralized section


Author(s): L. Prost, J.-P. Carneiro, and A. Shemyakin

In a low energy beam transport line (LEBT), the emittance growth due to the beam’s space charge is typically suppressed by way of neutralization from either electrons or ions, which originate from ionization of the background gas. In cases where the beam is chopped, the neutralization pattern usuall...

[Phys. Rev. Accel. Beams 21, 020101] Published Tue Feb 06, 2018

Resonant excitation of high order modes in the 3.9 GHz cavity of the Linac Coherent Light Source


Author(s): A. Lunin, T. Khabiboulline, N. Solyak, A. Sukhanov, and V. Yakovlev

Construction of the Linac Coherent Light Source II (LCLS-II) is underway for the world’s first hard x-ray free-electron laser. A central part of the LCLS-II project is a 4 GeV superconducting radio frequency electron linac that will operate in the continuous wave (cw) mode. The linac is segmented in...

[Phys. Rev. Accel. Beams 21, 022001] Published Tue Feb 06, 2018

Vertical-longitudinal coupling induced by wakefields at the Cornell Electron-Positron Storage Ring Test Accelerator


Author(s): S. T. Wang, J. D. Perrin, S. Poprocki, W. Hartung, and D. L. Rubin

Transverse vertical wakefields can increase vertical emittance and distort the phase space of a bunch in a storage ring. Here we report recent measurements and simulations of these effects from wakefields from movable scrapers at the Cornell electron-positron storage ring test accelerator. Charge-de...

[Phys. Rev. Accel. Beams 21, 024401] Published Mon Feb 05, 2018

High quality ion acceleration through the interaction of two matched counterpropagating transversely polarized Gaussian lasers with a flat foil target


Author(s): Weijun Zhou, Xueren Hong, Baisong Xie, Yang Yang, Li Wang, Jianmin Tian, Rongan Tang, and Wenshan Duan

In order to generate high quality ion beams through a relatively uniform radiation pressure acceleration (RPA) of a common flat foil, a new scheme is proposed to overcome the curve of the target while being radiated by a single transversely Gaussian laser. In this scheme, two matched counterpropaga...

[Phys. Rev. Accel. Beams 21, 021301] Published Fri Feb 02, 2018

Electron cooling of a bunched ion beam in a storage ring


Author(s): He Zhao, Lijun Mao, Jiancheng Yang, Jiawen Xia, Xiaodong Yang, Jie Li, Meitang Tang, Guodong Shen, Xiaoming Ma, Bo Wu, Geng Wang, Shuang Ruan, Kedong Wang, and Ziqiang Dong

A combination of electron cooling and rf system is an effective method to compress the beam bunch length in storage rings. A simulation code based on multiparticle tracking was developed to calculate the bunched ion beam cooling process, in which the electron cooling, intrabeam scattering (IBS), ion...

[Phys. Rev. Accel. Beams 21, 023501] Published Fri Feb 02, 2018

Parametric Landau damping of space charge modes


Author(s): Alexandru Macridin, Alexey Burov, Eric Stern, James Amundson, and Panagiotis Spentzouris

Landau damping is the mechanism of plasma and beam stabilization; it arises through energy transfer from collective modes to the incoherent motion of resonant particles. Normally this resonance requires the resonant particle’s frequency to match the collective mode frequency. We have identified an i...

[Phys. Rev. Accel. Beams 21, 011004] Published Mon Jan 29, 2018

High field $Q$ slope and the effect of low-temperature baking at 3 GHz


Author(s): G. Ciovati, G. Eremeev, and F. Hannon

A strong degradation of the unloaded quality factor with field, called high field $Q$ slope, is commonly observed above ${\mathrm{B}}_{p}≅100\text{ }\text{ }\mathrm{mT}$ in elliptical superconducting niobium cavities at 1.3 and 1.5 GHz. In the present experiments several 3 GHz niobium cavities were ...

[Phys. Rev. Accel. Beams 21, 012002] Published Mon Jan 29, 2018

High-charge relativistic electron bunches from a kHz laser-plasma accelerator


Author(s): D. Gustas, D. Guénot, A. Vernier, S. Dutt, F. Böhle, R. Lopez-Martens, A. Lifschitz, and J. Faure

Development of a compact source with a wide range of applications could stimulate significant work in many areas.

[Phys. Rev. Accel. Beams 21, 013401] Published Mon Jan 29, 2018

Final focus system tuning studies towards Compact Linear Collider feasibility


Author(s): E. Marin, A. Latina, R. Tomás, and D. Schulte

In this paper we present the latest results regarding the tuning study of the baseline design of the final focus system of the Compact Linear Collider (CLIC-FFS). CLIC aims to provide collisions to the experiments at a luminosity above ${10}^{34}\text{ }\text{ }\mathrm{c}{\mathrm{m}}^{−2}\text{ }{\m...

[Phys. Rev. Accel. Beams 21, 011003] Published Fri Jan 19, 2018

Nanomodulated electron beams via electron diffraction and emittance exchange for coherent x-ray generation


Author(s): E. A. Nanni, W. S. Graves, and D. E. Moncton

A new concept for compact x-ray sources.

[Phys. Rev. Accel. Beams 21, 014401] Published Fri Jan 19, 2018

Comprehensive study of beam focusing by crystal devices


Author(s): W. Scandale et al.

This paper is devoted to an experimental study of focusing and defocusing positively charged particle beams with the help of specially bent single crystals. Four crystals have been fabricated for this purpose. The studies have been performed at the CERN SPS in $400\text{ }\text{ }\mathrm{GeV}/c$ pro...

[Phys. Rev. Accel. Beams 21, 014702] Published Thu Jan 18, 2018

Exact cancellation of emittance growth due to coupled transverse dynamics in solenoids and rf couplers


Author(s): David H. Dowell, Feng Zhou, and John Schmerge

Weak, rotated magnetic and radio frequency quadrupole fields in electron guns and injectors can couple the beam’s horizontal with vertical motion, introduce correlations between otherwise orthogonal transverse momenta, and reduce the beam brightness. This paper discusses two important sources of cou...

[Phys. Rev. Accel. Beams 21, 010101] Published Wed Jan 17, 2018

Quadrupole-free detector optics design for the Compact Linear Collider final focus system at 3 TeV


Author(s): Fabien Plassard, Andrea Latina, Eduardo Marin, Rogelio Tomás, and Philip Bambade

Aiming to simplify the machine detector interface of the Compact Linear Collider (CLIC), a new detector model has been designed allowing the last quadrupole QD0 of the final focus system (FFS) to be located outside of the experiment with a distance ${L}^{*}$ from the interaction point of 6 m. In thi...

[Phys. Rev. Accel. Beams 21, 011002] Published Wed Jan 17, 2018

Emittance preservation of an electron beam in a loaded quasilinear plasma wakefield


Author(s): Veronica K. Berglyd Olsen, Erik Adli, and Patric Muggli

We investigate beam loading and emittance preservation for a high-charge electron beam being accelerated in quasilinear plasma wakefields driven by a short proton beam. The structure of the studied wakefields are similar to those of a long, modulated proton beam, such as the AWAKE proton driver. We ...

[Phys. Rev. Accel. Beams 21, 011301] Published Tue Jan 16, 2018

Compact and intense parametric x-ray radiation source based on a linear accelerator with cryogenic accelerating and decelerating copper structures


Author(s): J. Hyun, M. Satoh, M. Yoshida, T. Sakai, Y. Hayakawa, T. Tanaka, K. Hayakawa, I. Sato, and K. Endo

This paper describes a proposal for a compact x-ray source based on parametric x-ray radiation (PXR). The PXR, which is produced when a single crystal is bombarded with relativistic electrons, has good monochromaticity and spatial coherence, and is expected to be well suited for imaging of low-Z mat...

[Phys. Rev. Accel. Beams 21, 014701] Published Thu Jan 11, 2018

Extension of Busch’s theorem to particle beams


Author(s): L. Groening, C. Xiao, and M. Chung

In 1926, H. Busch formulated a theorem for one single charged particle moving along a region with a longitudinal magnetic field [H. Busch, Berechnung der Bahn von Kathodenstrahlen in axial symmetrischen electromagnetischen Felde, Z. Phys. 81, 974 (1926)]. The theorem relates particle angular momentu...

[Phys. Rev. Accel. Beams 21, 014201] Published Wed Jan 10, 2018

Stabilization of the arrival time of a relativistic electron beam to the 50 fs level


Author(s): J. Roberts, P. Skowronski, P. N. Burrows, G. B. Christian, R. Corsini, A. Ghigo, F. Marcellini, and C. Perry

We report the results of a low-latency beam phase feed-forward system built to stabilize the arrival time of a relativistic electron beam. The system was operated at the Compact Linear Collider (CLIC) Test Facility (CTF3) at CERN where the beam arrival time was stabilized to approximately 50 fs. The...

[Phys. Rev. Accel. Beams 21, 011001] Published Tue Jan 09, 2018

Announcement: Corrections in Physical Review Publications


[Phys. Rev. Accel. Beams 21, 010002] Published Wed Jan 03, 2018

Reduction and compensation of the transient beam loading effect in a double rf system of synchrotron light sources


Author(s): Naoto Yamamoto, Takeshi Takahashi, and Shogo Sakanaka

Double rf systems are used to lengthen the beam bunches in synchrotron light sources. In such a system, the performance of the bunch lengthening is limited by the transient beam-loading effect, which is induced by gaps in the fill pattern. To improve its performance, we investigate an application of...

[Phys. Rev. Accel. Beams 21, 012001] Published Wed Jan 03, 2018

Editorial: A Tale of Two Anniversaries: 125 Years of the Physical Review and 25 Years of Physical Review E


Author(s): Matthew Salter and Michael Thoennessen
[Phys. Rev. Accel. Beams 21, 010001] Published Tue Jan 02, 2018

High efficiency laser-assisted ${\mathrm{H}}^{−}$ charge exchange for microsecond duration beams


Author(s): Sarah Cousineau, Abdurahim Rakhman, Martin Kay, Alexander Aleksandrov, Viatcheslav Danilov, Timofey Gorlov, Yun Liu, Cary Long, Alexander Menshov, Michael Plum, Andrei Shishlo, Andrew Webster, and David Johnson

Laser-assisted stripping is a novel approach to ${\mathrm{H}}^{−}$ charge exchange that overcomes long-standing limitations associated with the traditional, foil-based method of producing high-intensity, time-structured beams of protons. This paper reports on the first successful demonstration of th...

[Phys. Rev. Accel. Beams 20, 120402] Published Tue Dec 26, 2017

Design and cold model experiment of a continuous-wave deuteron radio-frequency quadrupole


Author(s): Q. Fu, K. Zhu, Y. R. Lu, M. J. Easton, S. L. Gao, Z. Wang, F. J. Jia, H. P. Li, P. P. Gan, and Y. He

A deuteron radio-frequency quadrupole (RFQ) is being built by the RFQ group at Peking University. It is a very compact high-current RFQ, operating at 162.5 MHz in continuous-wave mode. By optimizing the beam dynamics design, our simulations reached 98% transmission efficiency for acceleration of the...

[Phys. Rev. Accel. Beams 20, 120101] Published Fri Dec 22, 2017

Overtaking collision effects in a cw double-pass proton linac


Author(s): Yue Tao, Ji Qiang, and Kilean Hwang

The recirculating superconducting proton linac has the advantage of reducing the number of cavities in the accelerator and the corresponding construction and operational costs. Beam dynamics simulations were done recently in a double-pass recirculating proton linac using a single proton beam bunch. ...

[Phys. Rev. Accel. Beams 20, 124202] Published Fri Dec 22, 2017

Efficiency versus instability in plasma accelerators


Author(s): Valeri Lebedev, Alexey Burov, and Sergei Nagaitsev

Plasma wakefield acceleration is one of the main technologies being developed for future high-energy colliders. Potentially, it can create a cost-effective path to the highest possible energies for ${e}^{+}{e}^{−}$ or $γ−γ$ colliders and produce a profound effect on the developments for high-energy ...

[Phys. Rev. Accel. Beams 20, 121301] Published Wed Dec 20, 2017

High-gradient low-$β$ accelerating structure using the first negative spatial harmonic of the fundamental mode


Author(s): Sergey V. Kutsaev, Ronald Agustsson, Salime Boucher, Richard Fischer, Alex Murokh, Brahim Mustapha, Alireza Nassiri, Peter N. Ostroumov, Alexander Plastun, Evgeny Savin, and Alexander Yu. Smirnov

The development of high-gradient accelerating structures for low-$β$ particles is the key for compact hadron linear accelerators. A particular example of such a machine is a hadron therapy linac, which is a promising alternative to cyclic machines, traditionally used for cancer treatment. Currently,...

[Phys. Rev. Accel. Beams 20, 120401] Published Tue Dec 19, 2017

Helical undulator based on partial redistribution of uniform magnetic field


Author(s): N. Balal, I. V. Bandurkin, V. L. Bratman, and A. E. Fedotov

A new type of helical undulator based on redistribution of magnetic field of a solenoid by ferromagnetic helix has been proposed and studied both in theory and experiment. Such undulators are very simple and efficient for promising sources of coherent spontaneous THz undulator radiation from dense e...

[Phys. Rev. Accel. Beams 20, 122401] Published Tue Dec 19, 2017

Higher-order mode-based cavity misalignment measurements at the free-electron laser FLASH


Author(s): Thorsten Hellert, Nicoleta Baboi, and Liangliang Shi

At the Free-Electron Laser in Hamburg (FLASH) and the European X-Ray Free-Electron Laser, superconducting TeV-energy superconducting linear accelerator (TESLA)-type cavities are used for the acceleration of electron bunches, generating intense free-electron laser (FEL) beams. A long rf pulse structu...

[Phys. Rev. Accel. Beams 20, 123501] Published Tue Dec 19, 2017

Announcement: Changes to the Table of Contents of Physical Review Accelerators and Beams


[Phys. Rev. Accel. Beams 20, 120001] Published Mon Dec 18, 2017

Sideband instability analysis based on a one-dimensional high-gain free electron laser model


Author(s): Cheng-Ying Tsai, Juhao Wu, Chuan Yang, Moohyun Yoon, and Guanqun Zhou

When an untapered high-gain free electron laser (FEL) reaches saturation, the exponential growth ceases and the radiation power starts to oscillate about an equilibrium. The FEL radiation power or efficiency can be increased by undulator tapering. For a high-gain tapered FEL, although the power is e...

[Phys. Rev. Accel. Beams 20, 120702] Published Mon Dec 18, 2017

Numerical investigation of space charge effects on the positions of beamlets for transversely split beams


Author(s): S. Machida, C. Prior, S. Gilardoni, M. Giovannozzi, A. Huschauer, and S. Hirlander

The use of transversely split beams was proposed some years ago as a means to perform extraction from a circular particle accelerator over multiple turns. In the course of studies carried out to increase understanding of the beam behavior, space charge effects have been probed. The experimental resu...

[Phys. Rev. Accel. Beams 20, 121001] Published Fri Dec 15, 2017

Microbunching instability study in a linac-driven free electron laser spreader beam line


Author(s): S. Di Mitri and S. Spampinati

Suppression of the microbunching instability is a priority for free electron lasers (FELs) whose goal is production of intense coherent radiation with very narrow spectral bandwidth. The instability can have large gain in multibend switchyard lines that connect the accelerator to multiple undulator ...

[Phys. Rev. Accel. Beams 20, 120701] Published Thu Dec 14, 2017

Photocathode quantum efficiency of ultrathin ${\mathrm{Cs}}_{2}\mathrm{Te}$ layers on Nb substrates


Author(s): Zikri Yusof, Adam Denchfield, Mark Warren, Javier Cardenas, Noah Samuelson, Linda Spentzouris, John Power, and John Zasadzinski

The quantum efficiencies (QE) of photocathodes consisting of bulk Nb substrates coated with thin films of ${\mathrm{Cs}}_{2}\mathrm{Te}$ are reported. Using the standard recipe for ${\mathrm{Cs}}_{2}\mathrm{Te}$ deposition developed for Mo substrates (220 Å Te thickness), a $\mathrm{QE}∼11%–13%$ at ...

[Phys. Rev. Accel. Beams 20, 123401] Published Thu Dec 14, 2017

Realistic simulations of a cyclotron spiral inflector within a particle-in-cell framework


Author(s): Daniel Winklehner, Andreas Adelmann, Achim Gsell, Tulin Kaman, and Daniela Campo

We present an upgrade to the particle-in-cell ion beam simulation code opal that enables us to run highly realistic simulations of the spiral inflector system of a compact cyclotron. This upgrade includes a new geometry class and field solver that can handle the complicated boundary conditions posed...

[Phys. Rev. Accel. Beams 20, 124201] Published Mon Dec 11, 2017

Evolution of a beam dynamics model for the transport line in a proton therapy facility


Author(s): V. Rizzoglio, A. Adelmann, C. Baumgarten, M. Frey, A. Gerbershagen, D. Meer, and J. M. Schippers

During the conceptual design of an accelerator or beamline, first-order beam dynamics models are essential for studying beam properties. However, they can only produce approximate results. During commissioning, these approximate results are compared to measurements, which will rarely coincide if the...

[Phys. Rev. Accel. Beams 20, 124702] Published Mon Dec 11, 2017

Computer codes for beam dynamics analysis of cyclotronlike accelerators


Author(s): V. Smirnov

Computer codes suitable for the study of beam dynamics in cyclotronlike (classical and isochronous cyclotrons, synchrocyclotrons, and fixed field alternating gradient) accelerators are reviewed. Computer modeling of cyclotron segments, such as the central zone, acceleration region, and extraction sy...

[Phys. Rev. Accel. Beams 20, 124801] Published Mon Dec 11, 2017

Development of a radio-frequency quadrupole cooler for high beam currents


Author(s): Ramzi Boussaid, G. Ban, G. Quéméner, Y. Merrer, and J. Lorry

The SHIRaC prototype is a recently developed radio-frequency quadrupole (RFQ) beam cooler with an improved optics design to deliver the required beam quality to a high resolution separator (HRS). For an isobaric separation of isotopes, the HRS demands beams with emittance not exceeding $3π\text{ }\t...

[Phys. Rev. Accel. Beams 20, 124701] Published Wed Dec 06, 2017

Gain cascading scheme of a free-electron-laser oscillator


Author(s): Kai Li and Haixiao Deng

The low-gain free-electron laser (FEL) oscillators are cutting-edge tools to produce fully coherent radiation in the spectral region from terahertz to vacuum ultraviolet, and potentially in hard x ray. In this paper, it is proposed to utilize an FEL oscillator with multistage undulators to enable ga...

[Phys. Rev. Accel. Beams 20, 110703] Published Thu Nov 30, 2017

Threshold of transverse mode coupling instability with arbitrary space charge


Author(s): V. Balbekov

The threshold of the transverse mode coupling instability is calculated in framework of the square well model at arbitrary value of space charge tune shift. A new method of calculation is developed beyond the traditional expansion technique. The square, resistive, and exponential wakes are investiga...

[Phys. Rev. Accel. Beams 20, 114401] Published Thu Nov 30, 2017

Upgrade possibilities for continuous wave rf electron guns based on room-temperature very high frequency technology


Author(s): F. Sannibale, D. Filippetto, M. Johnson, D. Li, T. Luo, C. Mitchell, J. Staples, S. Virostek, R. Wells, and J. M. Byrd

The past decade was characterized by an increasing scientific demand for extending towards higher repetition rates (MHz class and beyond) the performance of already operating lower repetition rate accelerator-based instruments such as x-ray free electron lasers (FELs) and ultrafast electron diffract...

[Phys. Rev. Accel. Beams 20, 113402] Published Mon Nov 27, 2017

Local correction of quadrupole errors at LHC interaction regions using action and phase jump analysis on turn-by-turn beam position data


Author(s): Javier Fernando Cardona, Alba Carolina García Bonilla, and Rogelio Tomás García

This article shows that the effect of all quadrupole errors present in an interaction region with low $β*$ can be modeled by an equivalent magnetic kick, which can be estimated from action and phase jumps found on beam position data. This equivalent kick is used to find the strengths that certain no...

[Phys. Rev. Accel. Beams 20, 111004] Published Wed Nov 22, 2017

Unavoidable trapped mode in the interaction region of colliding beams


Author(s): Alexander Novokhatski, Michael Sullivan, Eleonora Belli, Miguel Gil Costa, and Roberto Kersevan

We discuss the nature of the electromagnetic fields excited by the beams in the beam pipe of an interaction region. In trying to find an optimum geometry for this region with a minimum of electromagnetic wave excitation, we have discovered one mode, which remains even in a very smooth geometry. This...

[Phys. Rev. Accel. Beams 20, 111005] Published Wed Nov 22, 2017

Characterizing temporal coherence of visible synchrotron radiation with heterodyne near field speckles


Author(s): M. Siano, B. Paroli, M. A. C. Potenza, U. Iriso, A. A. Nosych, L. Torino, S. Mazzoni, G. Trad, and A. N. Goldblatt

In this paper we extensively describe the heterodyne near field speckle method (HNFS) to characterize both spatial and temporal coherence of synchrotron radiation (SR). The method relies on Fourier analysis of near field speckles generated by scattering from nanoparticles suspended in a liquid. A cr...

[Phys. Rev. Accel. Beams 20, 110702] Published Tue Nov 21, 2017

Accelerator performance analysis of the Fermilab Muon Campus


Author(s): Diktys Stratakis, Mary E. Convery, Carol Johnstone, John Johnstone, James P. Morgan, Dean Still, Jason D. Crnkovic, Vladimir Tishchenko, William M. Morse, and Michael J. Syphers

Fermilab is dedicated to hosting world-class experiments in search of new physics that will operate in the coming years. The Muon g-2 Experiment is one such experiment that will determine with unprecedented precision the muon anomalous magnetic moment, which offers an important test of the Standard ...

[Phys. Rev. Accel. Beams 20, 111003] Published Tue Nov 21, 2017

High quality electron bunch generation using a longitudinal density-tailored plasma-based accelerator in the three-dimensional blowout regime


Author(s): X. L. Xu, F. Li, W. An, T. N. Dalichaouch, P. Yu, W. Lu, C. Joshi, and W. B. Mori

Plasma-based acceleration in density down ramps is proposed to generate electron beams with unprecedented combinations of brightness and energy spread, which can drive a new class of compact free-electron-lasers and linear colliders.

[Phys. Rev. Accel. Beams 20, 111303] Published Tue Nov 21, 2017

Transparent lattice characterization with gated turn-by-turn data of diagnostic bunch train


Author(s): Yongjun Li, Weixing Cheng, Kiman Ha, and Robert Rainer

Methods of characterization of a storage ring’s lattice have traditionally been intrusive to routine operations. More importantly, the lattice seen by particles can drift with the beam current due to collective effects. To circumvent this, we have developed a novel approach for dynamically character...

[Phys. Rev. Accel. Beams 20, 112802] Published Tue Nov 21, 2017

First accelerator test of vacuum components with laser-engineered surfaces for electron-cloud mitigation


Author(s): Sergio Calatroni, Elisa Garcia-Tabares Valdivieso, Holger Neupert, Valentin Nistor, Ana Teresa Perez Fontenla, Mauro Taborelli, Paolo Chiggiato, Oleg Malyshev, Reza Valizadeh, Stefan Wackerow, Svetlana A. Zolotovskaya, W. Allan Gillespie, and Amin Abdolvand

Laser treatment of an accelerator vacuum chamber is shown to be an efficient and robust measure against electron-cloud formation.

[Phys. Rev. Accel. Beams 20, 113201] Published Mon Nov 20, 2017

High efficiency tapered free-electron lasers with a prebunched electron beam


Author(s): C. Emma, N. Sudar, P. Musumeci, A. Urbanowicz, and C. Pellegrini

In this paper we analyze the high gain, high efficiency tapered free-electron laser amplifier with a prebunched electron beam. Simple scaling laws are derived for the peak output power and extraction efficiency and verified using 1D simulations. These studies provide useful analytical expressions wh...

[Phys. Rev. Accel. Beams 20, 110701] Published Fri Nov 17, 2017

Publisher’s Note: Model-based optimization of tapered free-electron lasers [Phys. Rev. ST Accel. Beams 18, 040702 (2015)]


Author(s): Alan Mak, Francesca Curbis, and Sverker Werin
[Phys. Rev. Accel. Beams 20, 119902] Published Fri Nov 17, 2017

Publisher’s Note: Phase jump method for efficiency enhancement in free-electron lasers [Phys. Rev. Accel. Beams 20, 060703 (2017)]


Author(s): Alan Mak, Francesca Curbis, and Sverker Werin
[Phys. Rev. Accel. Beams 20, 119901] Published Tue Nov 14, 2017

Analytical $N$ beam position monitor method


Author(s): A. Wegscheider, A. Langner, R. Tomás, and A. Franchi

Measurement and correction of focusing errors is of great importance for performance and machine protection of circular accelerators. Furthermore LHC needs to provide equal luminosities to the experiments ATLAS and CMS. High demands are also set on the speed of the optics commissioning, as the fores...

[Phys. Rev. Accel. Beams 20, 111002] Published Fri Nov 10, 2017

Development for a supercompact $X$-band pulse compression system and its application at SLAC


Author(s): Juwen W. Wang, Sami G. Tantawi, Chen Xu, Matt Franzi, Patrick Krejcik, Gordon Bowden, Shantha Condamoor, Yuantao Ding, Valery Dolgashev, John Eichner, Andrew Haase, James R. Lewandowski, and Liling Xiao

We have successfully designed, fabricated, installed, and tested a super compact $X$-band SLAC Energy Doubler system at SLAC. It is composed of an elegant 3 dB coupler–mode converter–polarizer coupled to a single spherical energy storage cavity with high ${Q}_{0}$ of 94000 and a diameter less than 1...

[Phys. Rev. Accel. Beams 20, 110401] Published Thu Nov 09, 2017

Temperature-dependent quantum efficiency degradation of K-Cs-Sb bialkali antimonide photocathodes grown by a triple-element codeposition method


Author(s): Zihao Ding, Siddharth Karkare, Jun Feng, Daniele Filippetto, Matthew Johnson, Steve Virostek, Fernando Sannibale, James Nasiatka, Mengjia Gaowei, John Sinsheimer, Erik Muller, John Smedley, and Howard Padmore

K-Cs-Sb bialkali antimonide photocathodes grown by a triple-element codeposition method have been found to have excellent quantum efficiency (QE) and outstanding near-atomic surface smoothness and have been employed in the VHF gun in the Advanced Photoinjector Experiment (APEX), however, their robus...

[Phys. Rev. Accel. Beams 20, 113401] Published Thu Nov 09, 2017

Low energy tertiary beam line design for the CERN neutrino platform project


Author(s): N. Charitonidis and I. Efthymiopoulos

In the framework of CERN neutrino platform project at the CERN SPS North Area, two new beam lines have been designed as extensions of the existing secondary beam lines, able to provide low energy particles in the momentum range of 0.4 to $12\text{ }\text{ }\mathrm{GeV}/c$. The layout of these very l...

[Phys. Rev. Accel. Beams 20, 111001] Published Tue Nov 07, 2017

Beam dynamics analysis of dielectric laser acceleration using a fast 6D tracking scheme


Author(s): Uwe Niedermayer, Thilo Egenolf, and Oliver Boine-Frankenheim

An important step toward high fidelity beam-transport codes for dielectric laser accelerators is presented with the long-term goal of building an entire microchip-sized laser-driven accelerator.

[Phys. Rev. Accel. Beams 20, 111302] Published Fri Nov 03, 2017

rf design of a pulse compressor with correction cavity chain for klystron-based compact linear collider


Author(s): Ping Wang, Hao Zha, Igor Syratchev, Jiaru Shi, and Huaibi Chen

We present an X-band high-power pulse compression system for a klystron-based compact linear collider. In this system design, one rf power unit comprises two klystrons, a correction cavity chain, and two SLAC Energy Doubler (SLED)-type X-band pulse compressors (SLEDX). An rf pulse passes the correct...

[Phys. Rev. Accel. Beams 20, 112001] Published Fri Nov 03, 2017

Temporal profile monitor based on electro-optic spatial decoding for low-energy bunches


Author(s): Wei Wang, Yingchao Du, Lixin Yan, Zhijun Chi, Zhen Zhang, Jianfei Hua, Wenhui Huang, Chuanxiang Tang, and Ming Li

The measurement of electron bunch temporal profile is one of the key diagnostics in accelerators, especially for ultrashort bunches. The electro-optic (EO) technique enables the precise longitudinal characterization of bunch electric field in a single-shot and nondestructive way, which can simultane...

[Phys. Rev. Accel. Beams 20, 112801] Published Fri Nov 03, 2017

Emittance preservation in plasma-based accelerators with ion motion


Author(s): C. Benedetti, C. B. Schroeder, E. Esarey, and W. P. Leemans

In a plasma-accelerator-based linear collider, the density of matched, low-emittance, high-energy particle bunches required for collider applications can be orders of magnitude above the background ion density, leading to ion motion, perturbation of the focusing fields, and, hence, to beam emittance...

[Phys. Rev. Accel. Beams 20, 111301] Published Wed Nov 01, 2017

Magnesium diboride on inner wall of copper tube: A test case for superconducting radio frequency cavities


Author(s): Wenura K. Withanage, N. H. Lee, Sashank V. Penmatsa, M. A. Wolak, A. Nassiri, and X. X. Xi

Superconductor magnesium diboride is considered one of the viable materials to substitute bulk niobium for superconducting radio frequency cavities. Utilizing a ${\mathrm{MgB}}_{2}$ coating on the inner wall of a copper cavity will allow operation at higher temperatures (20–25 K) than Nb cavities du...

[Phys. Rev. Accel. Beams 20, 102002] Published Tue Oct 31, 2017

High-quality electron beam generation in a proton-driven hollow plasma wakefield accelerator


Author(s): Y. Li, G. Xia, K. V. Lotov, A. P. Sosedkin, K. Hanahoe, and O. Mete-Apsimon

Simulations of proton-driven plasma wakefield accelerators have demonstrated substantially higher accelerating gradients compared to conventional accelerators and the viability of accelerating electrons to the energy frontier in a single plasma stage. However, due to the strong intrinsic transverse ...

[Phys. Rev. Accel. Beams 20, 101301] Published Thu Oct 26, 2017

Spatial control of photoemitted electron beams using a microlens-array transverse-shaping technique


Author(s): A. Halavanau, G. Qiang, G. Ha, E. Wisniewski, P. Piot, J. G. Power, and W. Gai

A transversely inhomogeneous laser distribution on the photocathode surface generally produces electron beams with degraded beam quality. In this paper, we explore the use of microlens arrays to dramatically improve the transverse uniformity of an ultraviolet drive-laser pulse used in a photoinjecto...

[Phys. Rev. Accel. Beams 20, 103404] Published Thu Oct 26, 2017

Modeling of second order space charge driven coherent sum and difference instabilities


Author(s): Yao-Shuo Yuan, Oliver Boine-Frankenheim, and Ingo Hofmann

Second order coherent oscillation modes in intense particle beams play an important role for beam stability in linear or circular accelerators. In addition to the well-known second order even envelope modes and their instability, coupled even envelope modes and odd (skew) modes have recently been sh...

[Phys. Rev. Accel. Beams 20, 104201] Published Thu Oct 26, 2017

Temperature dependence of alkali-antimonide photocathodes: Evaluation at cryogenic temperatures


Author(s): M. A. Mamun, M. R. Hernandez-Flores, E. Morales, C. Hernandez-Garcia, and M. Poelker

${\mathrm{Cs}}_{x}{\mathrm{K}}_{y}\mathrm{Sb}$ photocathodes were manufactured on a niobium substrate and evaluated over a range of temperatures from 300 to 77 K. Vacuum conditions were identified that minimize surface contamination due to gas adsorption when samples were cooled below room temperatu...

[Phys. Rev. Accel. Beams 20, 103403] Published Tue Oct 24, 2017

Electromagnetic fields and Green’s functions in elliptical vacuum chambers


Author(s): S. Persichelli, N. Biancacci, M. Migliorati, L. Palumbo, and V. G. Vaccaro

In this paper, we discuss the electromagnetic interaction between a point charge travelling inside a waveguide of elliptical cross section, and the waveguide itself. By using a convenient expansion of the Mathieu functions, useful in particular for treating a variety of problems in applied mathemati...

[Phys. Rev. Accel. Beams 20, 101004] Published Mon Oct 23, 2017

Measurements of wake-induced electron beam deflection in a dechirper at the Linac Coherent Light Source


Author(s): Johann Zemella, Karl Bane, Alan Fisher, Marc Guetg, Zhirong Huang, Richard Iverson, Patrick Krejcik, Alberto Lutman, Timothy Maxwell, Alexander Novokhatski, Gennady Stupakov, Zhen Zhang, Mark Harrison, and Marcos Ruelas

The RadiaBeam/SLAC dechirper, a structure consisting of pairs of flat, metallic, corrugated plates, has been installed just upstream of the undulators in the Linac Coherent Light Source (LCLS). As a dechirper, with the beam passing between the plates on axis, longitudinal wakefields are induced that...

[Phys. Rev. Accel. Beams 20, 104403] Published Thu Oct 19, 2017

Aligning linac accelerating structures using a copropagating octupolar mode


Author(s): J. Ögren and V. Ziemann

We propose a novel method to align accelerating structures such as those used in the Compact Linear Collider (CLIC) by exploiting a mode that copropagates with the normal accelerating mode. This mode has an octupolar dependence in the transverse direction and is caused by radial waveguides intended ...

[Phys. Rev. Accel. Beams 20, 102801] Published Mon Oct 16, 2017

Medical therapy and imaging fixed-field alternating-gradient accelerator with realistic magnets


Author(s): S. Tygier, K. B. Marinov, R. B. Appleby, J. A. Clarke, J. M. Garland, H. L. Owen, and B. J. A. Shepherd

NORMA is a design for a normal-conducting racetrack fixed-field alternating-gradient accelerator for protons from 50 to 350 MeV. In this article we show the development from an idealized lattice to a design implemented with field maps from rigorous two-dimensional (2D) and three-dimensional (3D) FEM...

[Phys. Rev. Accel. Beams 20, 104702] Published Mon Oct 16, 2017

Optimal radius of crystal curvature for planar channeling of high-energy negatively charged particles in a bent crystal


Author(s): I. V. Kirillin

The problem of planar channeling of high-energy negatively charged particles in a bent crystal was considered on the basis of analytical calculation and numerical simulation. We show the existence of an optimal radius of crystal curvature for planar channeling, corresponding to the maximum deflectio...

[Phys. Rev. Accel. Beams 20, 104401] Published Fri Oct 13, 2017

Analysis of transverse beam stabilization with radio frequency quadrupoles


Author(s): M. Schenk, A. Grudiev, K. Li, and K. Papke

A radio frequency (rf) quadrupole has been considered as a potential alternative device for Landau damping in circular hadron colliders. The objective of this study is to benchmark and confirm its stabilizing effect predicted by stability diagram theory by means of numerical tracking simulations. To...

[Phys. Rev. Accel. Beams 20, 104402] Published Fri Oct 13, 2017

High current nonlinear transmission line based electron beam driver


Author(s): B. W. Hoff, D. M. French, D. S. Simon, P. D. Lepell, T. Montoya, and S. L. Heidger

A gigawatt-class nonlinear transmission line based electron beam driver is experimentally demonstrated. Four experimental series, each with a different Marx bank charge voltage (15, 20, 25, and 30 kV), were completed. Within each experimental series, shots at peak frequencies ranging from 950 MHz to...

[Phys. Rev. Accel. Beams 20, 100401] Published Thu Oct 12, 2017

Efficient model for low-energy transverse beam dynamics in a nine-cell 1.3 GHz cavity


Author(s): Thorsten Hellert, Martin Dohlus, and Winfried Decking

FLASH and the European XFEL are SASE-FEL user facilities, at which superconducting TESLA cavities are operated in a pulsed mode to accelerate long bunch-trains. Several cavities are powered by one klystron. While the low-level rf system is able to stabilize the vector sum of the accelerating gradien...

[Phys. Rev. Accel. Beams 20, 100702] Published Thu Oct 12, 2017

Cavity voltage phase modulation to reduce the high-luminosity Large Hadron Collider rf power requirements


Author(s): T. Mastoridis, P. Baudrenghien, and J. Molendijk

For uneven bunch filling patterns, adapting the rf voltage reference reduces the klystron power and allows operation at higher beam intensity.

[Phys. Rev. Accel. Beams 20, 101003] Published Tue Oct 10, 2017

3D multiphysics modeling of superconducting cavities with a massively parallel simulation suite


Author(s): Oleksiy Kononenko, Chris Adolphsen, Zenghai Li, Cho-Kuen Ng, and Claudio Rivetta

Radiofrequency cavities based on superconducting technology are widely used in particle accelerators for various applications. The cavities usually have high quality factors and hence narrow bandwidths, so the field stability is sensitive to detuning from the Lorentz force and external loads, includ...

[Phys. Rev. Accel. Beams 20, 102001] Published Tue Oct 10, 2017