- Multicomponent measurements of the Jefferson Lab energy recovery linac electron beam using optical transition and diffraction radiation
Author(s): M. A. Holloway, R. B. Fiorito, A. G. Shkvarunets, P. G. O’Shea, S. V. Benson, D. Douglas, P. Evtushenko, and K. Jordan
High brightness electron accelerators, such as energy recovery linacs (ERL), often have complex particle distributions that can create difficulties in beam transport as well as matching to devices such as wigglers used to generate radiation from the beam. Optical transition radiation (OTR), OTR inte...
[Phys. Rev. ST Accel. Beams 11, 082801] Published Thu Aug 14, 2008
- Chromaticity and wakefield effect on the transverse motion of longitudinal bunch slices in the Fermilab Tevatron
Author(s): V. H. Ranjbar and P. Ivanov
The transverse turn-by-turn evolution of a bunch slice after an impulse kick is examined considering chromatic and impedance effects. It is found that by fitting the envelope of the beam slice motion to simulated data the strength of the resistive wall wakefield can be determined.
[Phys. Rev. ST Accel. Beams 11, 084401] Published Wed Aug 13, 2008
- Multilayer tube impedance and external radiation
Author(s): M. Ivanyan, E. Laziev, V. Tsakanov, A. Vardanyan, S. Heifets, and A. Tsakanian
The paper describes a method for calculating the longitudinal and transverse impedances of the laminated round pipe with many layers of different materials. The charge is moving along the pipe axis with arbitrary constant velocity. The study is based on the field-matching technique applied for the a...
[Phys. Rev. ST Accel. Beams 11, 084001] Published Wed Aug 13, 2008
- Comparative study of heat transfer from Nb-Ti and Nb_{3} Sn coils to He II
Author(s): Marco La China and Davide Tommasini
In superconducting magnets, the energy deposited or generated in the coil must be evacuated to prevent temperature rise and consequent transition of the superconductor to the resistive state. The main barrier to heat extraction is represented by the electric insulation wrapped around superconducting...
[Phys. Rev. ST Accel. Beams 11, 082401] Published Thu Aug 07, 2008
- High-efficiency resonant rf spin rotator with broad phase space acceptance for pulsed polarized cold neutron beams
Author(s): P.-N. Seo et al.
High precision fundamental neutron physics experiments have been proposed for the intense pulsed spallation neutron beams at JSNS, LANSCE, and SNS to test the standard model and search for new physics. Certain systematic effects in some of these experiments have to be controlled at the few ppb level...
[Phys. Rev. ST Accel. Beams 11, 084701] Published Wed Aug 06, 2008
- Advanced plasma flow simulations of cathodic-arc and ferroelectric plasma sources for neutralized drift compression experiments
Author(s): Adam B. Sefkow, Ronald C. Davidson, and Erik P. Gilson
Large-space-scale and long-time-scale plasma flow simulations are executed in order to study the spatial and temporal evolution of plasma parameters for two types of plasma sources used in the neutralized drift compression experiment (NDCX). The results help assess the charge neutralization conditio...
[Phys. Rev. ST Accel. Beams 11, 070101] Published Thu Jul 31, 2008
- Longitudinal dispersion of orbital angular momentum modes in high-gain free-electron lasers
Author(s): Erik Hemsing, Agostino Marinelli, Sven Reiche, and James Rosenzweig
The physical effects of optical mode dispersion in the electron beam of a free-electron laser are investigated for modes that carry orbital angular momentum. The analysis is performed using a derived equivalence between two different formulations that describe the radiation fields in the linear regi...
[Phys. Rev. ST Accel. Beams 11, 070704] Published Wed Jul 30, 2008
- Ultrahigh brightness electron beams by plasma-based injectors for driving all-optical free-electron lasers
Author(s): V. Petrillo, L. Serafini, and P. Tomassini
We studied the generation of low emittance high current monoenergetic beams from plasma waves driven by ultrashort laser pulses, in view of achieving beam brightness of interest for free-electron laser (FEL) applications. The aim is to show the feasibility of generating nC charged beams carrying pea...
[Phys. Rev. ST Accel. Beams 11, 070703] Published Tue Jul 29, 2008
- Electron acceleration by amplified wakefield generated by two copropagating laser pulses in plasma
Author(s): Gaurav Raj, Ajay K. Upadhyaya, Rohit K. Mishra, and Pallavi Jha
A detailed analytical theory is developed for studying the phenomenon of generation of high amplitude wakefield using a seed laser pulse and another coaxially propagating, trailing pulse. The two laser pulses are separated by a fixed distance between them and have the same polarization, frequency, l...
[Phys. Rev. ST Accel. Beams 11, 071301] Published Mon Jul 28, 2008
- Dynamic compensation of an rf cavity failure in a superconducting linac
Author(s): Jean-Luc Biarrotte and Didier Uriot
An accelerator driven system (ADS) for transmutation of nuclear waste typically requires a 600 MeV–1 GeV accelerator delivering a proton flux of a few mA for demonstrators, and of a few tens of mA for large industrial systems. Such a machine belongs to the category of the high-power proton accel...
[Phys. Rev. ST Accel. Beams 11, 072803] Published Thu Jul 24, 2008
- Observation of two-dimensional longitudinal-transverse correlations in an electron beam by laser-electron interactions
Author(s): G. Angelova, V. Ziemann, A. Meseck, P. Salén, P. van der Meulen, M. Hamberg, M. Larsson, J. Bödewadt, S. Khan, A. Winter, H. Schlarb, F. Löhl, E. Saldin, E. Schneidmiller, and M. Yurkov
During the preparatory work for the optical-replica synthesizer experiment in the free-electron laser FLASH at DESY, we were able to superimpose a short, approximately 200 fs long pulse from a frequency-doubled mode-locked erbium laser with titanium-sapphire amplifier and an approximately 20 ps lo...
[Phys. Rev. ST Accel. Beams 11, 070702] Published Thu Jul 24, 2008
- Compensation of wakefield-driven energy spread in energy recovery linacs
Author(s): Georg H. Hoffstaetter and Yang Hao Lau
Energy recovery linacs provide high-energy beams, but decelerate those beams before dumping them, so that their energy is available for the acceleration of new particles. During this deceleration, any relative energy spread that is created at high energy is amplified by the ratio between high energy...
[Phys. Rev. ST Accel. Beams 11, 070701] Published Wed Jul 23, 2008
- Publisher’s Note: High intensity ion beams in rf undulator linac [Phys. Rev. ST Accel. Beams 11, 074201 (2008)]
Author(s): E. S. Masunov and S. M. Polozov
[Phys. Rev. ST Accel. Beams 11, 079901] Published Tue Jul 22, 2008
- Measurement and simulation of transverse Schottky noise with space charge
Author(s): O. Boine-Frankenheim, V. Kornilov, and S. Paret
The effect of moderate space charge on the transverse Schottky spectrum of a coasting beam is studied using measurements and simulations together with an analytic model. The measurements of transverse Schottky bands from heavy ion beams were performed in the SIS-18 synchrotron at GSI. In addition, w...
[Phys. Rev. ST Accel. Beams 11, 074202] Published Thu Jul 17, 2008
- Dual-harmonic auto voltage control for the rapid cycling synchrotron of the Japan Proton Accelerator Research Complex
Author(s): Fumihiko Tamura, Alexander Schnase, and Masahito Yoshii
The dual-harmonic operation, in which the accelerating cavities are driven by the superposition of the fundamental and the second harmonic rf voltage, is useful for acceleration of the ultrahigh intensity proton beam in the rapid cycling synchrotron (RCS) of Japan Proton Accelerator Research Complex...
[Phys. Rev. ST Accel. Beams 11, 072001] Published Thu Jul 17, 2008
- Electromagnetic field and short-range wake function in a beam pipe of elliptical cross section
Author(s): A. Lutman, R. Vescovo, and P. Craievich
Within the ultrarelativistic limit, analytical expressions are found for the high-frequency resistive-wall coupling impedance of an elliptical cross-section vacuum chamber. Subsequently, the corresponding wake functions are derived by performing inverse Fourier transformations numerically. The elect...
[Phys. Rev. ST Accel. Beams 11, 074401] Published Mon Jul 14, 2008
- High intensity ion beams in rf undulator linac
Author(s): E. S. Masunov and S. M. Polozov
The possibility of using a radio frequency undulator field to accelerate a high intensity ion beam in a linac is discussed. Such an accelerator can be realized using the periodical interdigital H-type resonator structure. The accelerating force is produced by an electric field which is a combination...
[Phys. Rev. ST Accel. Beams 11, 074201] Published Thu Jul 10, 2008
- Numerical studies on the electro-optic detection of femtosecond electron bunches
Author(s): S. Casalbuoni, H. Schlarb, B. Schmidt, P. Schmüser, B. Steffen, and A. Winter
The electro-optic (EO) effect is a powerful diagnostic tool for determining the time profile of ultrashort relativistic electron bunches. When a relativistic bunch passes within a few mm of an electro-optic crystal, its transient electric field is equivalent to a half-cycle THz pulse passing through...
[Phys. Rev. ST Accel. Beams 11, 072802] Published Wed Jul 09, 2008
- Automated correction of phase errors in the Advanced Photon Source linac
Author(s): N. S. Sereno, M. Borland, and R. Lill
Maintaining stable phasing in a linear accelerator is crucial for maintaining optimal performance. If phasing is incorrect, the beam will in general have an energy error and increased energy spread. While an energy error can be readily detected and corrected using position readings from beam positio...
[Phys. Rev. ST Accel. Beams 11, 072801] Published Tue Jul 08, 2008
- Robust CsBr/Cu photocathodes for the linac coherent light source
Author(s): Juan R. Maldonado, Zhi Liu, D. H. Dowell, Robert E. Kirby, Yun Sun, Piero Pianetta, and Fabian Pease
The linac coherent light source (LCLS), an x-ray free-electron laser project presently under construction at SLAC, uses a 2.856 GHz rf photocathode gun with a copper cathode for its electron source. While the copper cathode is performing well for the LCLS project, a cathode material with higher qua...
[Phys. Rev. ST Accel. Beams 11, 060702] Published Wed Jun 25, 2008
- International Linear Collider damping ring lattice design based on modified FODO arc cells
Author(s): Y. P. Sun, J. Gao, Z. Y. Guo, and W. S. Wan
In this paper, we present a new lattice design for the International Linear Collider (ILC) positron damping ring. The same lattice could be used also for the electron damping ring. This lattice is based on modified FODO arc cells, and has a freely tunable momentum compaction factor from 2×10^{-4} t...
[Phys. Rev. ST Accel. Beams 11, 061001] Published Mon Jun 23, 2008
- Development of a 5.4 MV laser triggered gas switch for multimodule, multimegampere pulsed power drivers
Author(s): K. R. LeChien, M. E. Savage, V. Anaya, D. E. Bliss, W. T. Clark, J. P. Corley, G. Feltz, J. E. Garrity, D. W. Guthrie, K. C. Hodge, J. E. Maenchen, R. Maier, K. R. Prestwich, K. W. Struve, W. A. Stygar, T. Thompson, J. Van Den Avyle, P. E. Wakeland, Z. R. Wallace, and J. R. Woodworth
Laser triggered, megavolt, megampere gas switches are frequently utilized to synchronize multiple pulsed power driver modules for inertial-confinement fusion, isentropic compression, and radiation physics experiments. The device developed to synchronize the 36 modules of the refurbished Z accelerato...
[Phys. Rev. ST Accel. Beams 11, 060402] Published Wed Jun 18, 2008
- Analysis of longitudinal beam dynamics behavior and rf system operative limits at high-beam currents in storage rings
Author(s): T. Mastorides, C. Rivetta, J. D. Fox, D. Van Winkle, and D. Teytelman
A dynamics simulation model is used to estimate limits of performance of the positron-electron project (PEP-II). The simulation captures the dynamics and technical limitations of the low level radio frequency (LLRF) system, the high-power rf components, and the low-order mode coupled-bunch longitudi...
[Phys. Rev. ST Accel. Beams 11, 062802] Published Tue Jun 17, 2008
- Development of a high-resolution cavity-beam position monitor
Author(s): Yoichi Inoue, Hitoshi Hayano, Yosuke Honda, Toshikazu Takatomi, Toshiaki Tauchi, Junji Urakawa, Sachio Komamiya, Tomoya Nakamura, Tomoyuki Sanuki, Eun-San Kim, Seung-Hwan Shin, and Vladimir Vogel
We have developed a high-resolution cavity-beam position monitor (BPM) to be used at the focal point of the ATF2, which is a test beam line that is now being built to demonstrate stable orbit control at ∼nanometer resolution. The design of the cavity structure was optimized for the Accelerator Tes...
[Phys. Rev. ST Accel. Beams 11, 062801] Published Mon Jun 16, 2008
- Deflection of 400 GeV/c proton beam with bent silicon crystals at the CERN Super Proton Synchrotron
Author(s): Walter Scandale et al.
This paper presents a detailed study of the deflection phenomena of a 400 GeV/c proton beam impinging on a new generation of bent silicon crystals; the tests have been performed at the CERN Super Proton Synchrotron H8 beam line. Channeling and volume reflection angles are measured with an extre...
[Phys. Rev. ST Accel. Beams 11, 063501] Published Wed Jun 11, 2008
- Three-dimensional analysis of free-electron laser performance using brightness scaled variables
Author(s): M. Gullans, G. Penn, J. S. Wurtele, and M. Zolotorev
A three-dimensional analysis of radiation generation in a free-electron laser (FEL) is performed in the small signal regime. The analysis includes beam conditioning, harmonic generation, flat beams, and a new scaling of the FEL equations using the six-dimensional beam brightness. The six-dimensional...
[Phys. Rev. ST Accel. Beams 11, 060701] Published Wed Jun 11, 2008
- Source-to-target simulation of simultaneous longitudinal and transverse focusing of heavy ion beams
Author(s): D. R. Welch, J. E. Coleman, P. A. Seidl, P. K. Roy, E. Henestroza, E. P. Lee, A. B. Sefkow, E. P. Gilson, T. C. Genoni, and D. V. Rose
Longitudinal bunching factors in excess of 70 of a 300-keV, 27-mA K^{+} ion beam have been demonstrated in the neutralized drift compression experiment [P. K. Roy , Phys. Rev. Lett. 95, 234801 (2005)] in rough agreement with particle-in-cell source-to-target simulations. A key aspect of these expe...
[Phys. Rev. ST Accel. Beams 11, 064701] Published Mon Jun 09, 2008
- Applications of cavity transverse modes in accelerators
Author(s): V. Volkov and D. Janssen
Different applications of TE modes in accelerator physics are discussed. In this discussion, the Fourier transform of the squared axial component of magnetic field, B _{z} ^{2} (z), plays an important role. If it turns out to be zero, the rf field-particle energy transfer is negligible and the focal...
[Phys. Rev. ST Accel. Beams 11, 061302] Published Mon Jun 09, 2008
- Plasma evolution and dynamics in high-power vacuum-transmission-line post-hole convolutes
Author(s): D. V. Rose, D. R. Welch, T. P. Hughes, R. E. Clark, and W. A. Stygar
Vacuum-post-hole convolutes are used in pulsed high-power generators to join several magnetically insulated transmission lines (MITL) in parallel. Such convolutes add the output currents of the MITLs, and deliver the combined current to a single MITL that, in turn, delivers the current to a load. Ma...
[Phys. Rev. ST Accel. Beams 11, 060401] Published Fri Jun 06, 2008
- Production and characterization of attosecond electron bunch trains
Author(s): Christopher M. Sears, Eric Colby, Rasmus Ischebeck, Christopher McGuinness, Janice Nelson, Robert Noble, Robert H. Siemann, James Spencer, Dieter Walz, Tomas Plettner, and Robert L. Byer
We report the production of optically spaced attosecond electron microbunches produced by the inverse free-electron-laser (IFEL) process. The IFEL is driven by a Ti:sapphire laser synchronized with the electron beam. The IFEL is followed by a magnetic chicane that converts the energy modulation into...
[Phys. Rev. ST Accel. Beams 11, 061301] Published Thu Jun 05, 2008
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