LINAC2012 - Classification: 04 Extreme Beams, Sources and Other Technologies / 4D Beam Dynamics, Computer Simulation, Beam Transport

Paper

Title

Page

Multipole Field Effects for the Superconducting Parallel-Bar Deflecting/Crabbing Cavities

92

S.U. De Silva, J.R. Delayen
ODU, Norfolk, Virginia, USA
S.U. De Silva
JLAB, Newport News, Virginia, USA

The superconducting parallel-bar deflecting/crabbing cavity is currently being considered as one of the design options in rf separation for the Jefferson Lab 12 GeV upgrade and for the crabbing cavity for the proposed LHC luminosity upgrade. Knowledge of multipole field effects is important for accurate beam dynamics study of rf structures. The multipole components can be accurately determined numerically using the electromagnetic surface field data in the rf structure. This paper discusses the detailed analysis of those components for the fundamental deflecting/crabbing mode and higher order modes in the parallel-bar deflecting/crabbing cavity.

TU3A04

Electron Beam Current-profile Shaping via Transverse-to-longitudinal Phase-space Exchange

Y.-E. Sun
Fermilab, Batavia, USA

Tunable subpicosecond electron bunch trains are experimentally demonstrated at the A0 photoinjector at Fermilab. In this talk, we report our experiment on electron beam current-profile shaping using a transverse-to-longitudinal phase-space exchange technique. An initial beam consisting of a set of horizontally-separated beamlets passes through a beamline that exchanges the horizontal and longitudinal phase spaces, thus the beam is converted into a train of bunches temporally separated with tunable bunch duration and separation. By choosing proper initial horizontal density profiles, other types of beam current-profile shaping are possible, such as the preferred triangle-shape in wake field acceleration experiments.

Slides TU3A04 [1.924 MB]

TH1A05

Emittance-partitioning Strategies for Future Accelerator Applications

K. Bishofberger, M. Ben-Naim, B.E. Carlsten, L.D. Duffy, R.C. McCrady, N.A. Yampolsky
LANL, Los Alamos, New Mexico, USA

The prevailing limit on many linear-accelerator applications is the transverse emittances of the beam. For example, XFEL and collider performance depend on transverse emittances more than longitudinal, which for an XFEL can be up to three orders of magnitude larger than in the transverse dimensions. Recent theoretical treatment of eigen-emittance manipulations has offered a new capability to generate, in principle, extraordinarily bright electron beams. Specific strategies are explored which partition the six-dimensional phase space with a specific goal of deriving low transverse emittances, and examples leading to transverse emittances of 0.1 – 0.2 μm for 250 pC are provided.

Slides TH1A05 [1.858 MB]

THPLB11

Experimental and Simulation Study of the Long-path-length Dynamics of a Space-charge-dominated Bunch

834

I. Haber, B.L. Beaudoin, S. Bernal, R.A. Kishek, T.W. Koeth, Y. Mo
UMD, College Park, Maryland, USA

Funding: Work supported by the United States Department of Energy and the Office of Naval Research.
The University of Maryland Electron Ring (UMER) is a low-energy (10 keV) electron facility built to study, on a scaled machine, the long-propagation-length evolution of a space-charge-dominated beam. Though constructed in a ring geometry to achieve a long path length at modest cost, UMER has observed important space-charge physics directly relevant to linear machines. Examples will be presented that emphasize studies of the longitudinal dynamics and comparisons to axisymmetric simulations. The detailed agreement obtained between simulation and experiment will be presented as evidence that the longitudinal physics observed is not strongly influenced by the ring geometry. Novel phenomena such as soliton formation, unimpeded bunch-end interpenetration, and an instability that occurs after this interpenetration, will be discussed.

THPB061

Experimental and Simulation Study of the Long-path-length Dynamics of a Space-charge-dominated Bunch

978

I. Haber, B.L. Beaudoin, S. Bernal, R.A. Kishek, T.W. Koeth, Y. Mo
UMD, College Park, Maryland, USA

Funding: Work supported by the United States Department of Energy and the Office of Naval Research.
The University of Maryland Electron Ring (UMER) is a low-energy (10 keV) electron facility built to study, on a scaled machine, the long-propagation-length evolution of a space-charge-dominated beam. Though constructed in a ring geometry to achieve a long path length at modest cost, UMER has observed important space-charge physics directly relevant to linear machines. Examples will be presented that emphasize studies of the longitudinal dynamics and comparisons to axisymmetric simulations. The detailed agreement obtained between simulation and experiment will be presented as evidence that the longitudinal physics observed is not strongly influenced by the ring geometry. Novel phenomena such as soliton formation, unimpeded bunch-end interpenetration, and an instability that occurs after this interpenetration, will be discussed.

THPB062

Multipole Field Effects for the Superconducting Parallel-Bar/RF-Dipole Deflecting/Crabbing Cavities

981

S.U. De Silva, J.R. Delayen
ODU, Norfolk, Virginia, USA
S.U. De Silva
JLAB, Newport News, Virginia, USA

The superconducting parallel-bar deflecting/crabbing cavity is currently being considered as one of the design options in rf separation for the Jefferson Lab 12 GeV upgrade and for the crabbing cavity for the proposed LHC luminosity upgrade. Knowledge of multipole field effects is important for accurate beam dynamics study of rf structures. The multipole components can be accurately determined numerically using the electromagnetic surface field data in the rf structure. This paper discusses the detailed analysis of those components for the fundamental deflecting/crabbing mode and higher order modes in the parallel-bar deflecting/crabbing cavity.

THPB063

Simulated Performance of the CARIBU EBIS Charge Breeder Transport Line

984

C. Dickerson, S.A. Kondrashev, B. Mustapha, P.N. Ostroumov
ANL, Argonne, USA

Funding: This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract number DE-AC02-06CH11357.
An Electron Beam Ion Source (EBIS) has been designed and is being built to charge breed ions from the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) for post acceleration in the Argonne Tandem Linear Accelerator System (ATLAS). The calculated transverse acceptance of the EBIS charge breeder can approach the emittance of the injected ion beam, so beam distortion during transport could lead to incomplete injection and a decrease in the overall system efficiency. The beam quality can be maintained for simulations of the transport line using the ideal ion beam parameters. This paper reports the results of the electrostatic and ion beam transport simulations used to minimize the ion beam distortions by optimizing component designs and configurations.

THPB064

Beam Dynamics Tools for Linacs Design

987

A.S. Setty
THALES, Colombes, France

In the last 25 years, we have been using our in house 3D code PRODYN * for electron beam simulations. We have also been using our in house code SECTION for the design of the travelling wave accelerating structures and the beam loading compensation. PRODYN follows in time, the most complicated electron trajectories with relativistic space-charge effects. This code includes backward as well as forwards movements. This paper will describe those two codes and will give some simulations and measurements results.
* D. Tronc and A. Setty, Electrons RF auto-focusing and capture in bunchers, Linear Accelerator Conference 1988, Virginia.

Paper	Title	Page
SUPB038	Multipole Field Effects for the Superconducting Parallel-Bar Deflecting/Crabbing Cavities	92
	S.U. De Silva, J.R. Delayen ODU, Norfolk, Virginia, USA S.U. De Silva JLAB, Newport News, Virginia, USA
	The superconducting parallel-bar deflecting/crabbing cavity is currently being considered as one of the design options in rf separation for the Jefferson Lab 12 GeV upgrade and for the crabbing cavity for the proposed LHC luminosity upgrade. Knowledge of multipole field effects is important for accurate beam dynamics study of rf structures. The multipole components can be accurately determined numerically using the electromagnetic surface field data in the rf structure. This paper discusses the detailed analysis of those components for the fundamental deflecting/crabbing mode and higher order modes in the parallel-bar deflecting/crabbing cavity.

TU3A04	Electron Beam Current-profile Shaping via Transverse-to-longitudinal Phase-space Exchange
	Y.-E. Sun Fermilab, Batavia, USA
	Tunable subpicosecond electron bunch trains are experimentally demonstrated at the A0 photoinjector at Fermilab. In this talk, we report our experiment on electron beam current-profile shaping using a transverse-to-longitudinal phase-space exchange technique. An initial beam consisting of a set of horizontally-separated beamlets passes through a beamline that exchanges the horizontal and longitudinal phase spaces, thus the beam is converted into a train of bunches temporally separated with tunable bunch duration and separation. By choosing proper initial horizontal density profiles, other types of beam current-profile shaping are possible, such as the preferred triangle-shape in wake field acceleration experiments.
	Slides TU3A04 [1.924 MB]

TH1A05	Emittance-partitioning Strategies for Future Accelerator Applications
	K. Bishofberger, M. Ben-Naim, B.E. Carlsten, L.D. Duffy, R.C. McCrady, N.A. Yampolsky LANL, Los Alamos, New Mexico, USA
	The prevailing limit on many linear-accelerator applications is the transverse emittances of the beam. For example, XFEL and collider performance depend on transverse emittances more than longitudinal, which for an XFEL can be up to three orders of magnitude larger than in the transverse dimensions. Recent theoretical treatment of eigen-emittance manipulations has offered a new capability to generate, in principle, extraordinarily bright electron beams. Specific strategies are explored which partition the six-dimensional phase space with a specific goal of deriving low transverse emittances, and examples leading to transverse emittances of 0.1 – 0.2 μm for 250 pC are provided.
	Slides TH1A05 [1.858 MB]

THPLB11	Experimental and Simulation Study of the Long-path-length Dynamics of a Space-charge-dominated Bunch	834
	I. Haber, B.L. Beaudoin, S. Bernal, R.A. Kishek, T.W. Koeth, Y. Mo UMD, College Park, Maryland, USA
	Funding: Work supported by the United States Department of Energy and the Office of Naval Research. The University of Maryland Electron Ring (UMER) is a low-energy (10 keV) electron facility built to study, on a scaled machine, the long-propagation-length evolution of a space-charge-dominated beam. Though constructed in a ring geometry to achieve a long path length at modest cost, UMER has observed important space-charge physics directly relevant to linear machines. Examples will be presented that emphasize studies of the longitudinal dynamics and comparisons to axisymmetric simulations. The detailed agreement obtained between simulation and experiment will be presented as evidence that the longitudinal physics observed is not strongly influenced by the ring geometry. Novel phenomena such as soliton formation, unimpeded bunch-end interpenetration, and an instability that occurs after this interpenetration, will be discussed.

THPB061	Experimental and Simulation Study of the Long-path-length Dynamics of a Space-charge-dominated Bunch	978
	I. Haber, B.L. Beaudoin, S. Bernal, R.A. Kishek, T.W. Koeth, Y. Mo UMD, College Park, Maryland, USA
	Funding: Work supported by the United States Department of Energy and the Office of Naval Research. The University of Maryland Electron Ring (UMER) is a low-energy (10 keV) electron facility built to study, on a scaled machine, the long-propagation-length evolution of a space-charge-dominated beam. Though constructed in a ring geometry to achieve a long path length at modest cost, UMER has observed important space-charge physics directly relevant to linear machines. Examples will be presented that emphasize studies of the longitudinal dynamics and comparisons to axisymmetric simulations. The detailed agreement obtained between simulation and experiment will be presented as evidence that the longitudinal physics observed is not strongly influenced by the ring geometry. Novel phenomena such as soliton formation, unimpeded bunch-end interpenetration, and an instability that occurs after this interpenetration, will be discussed.

THPB062	Multipole Field Effects for the Superconducting Parallel-Bar/RF-Dipole Deflecting/Crabbing Cavities	981
	S.U. De Silva, J.R. Delayen ODU, Norfolk, Virginia, USA S.U. De Silva JLAB, Newport News, Virginia, USA
	The superconducting parallel-bar deflecting/crabbing cavity is currently being considered as one of the design options in rf separation for the Jefferson Lab 12 GeV upgrade and for the crabbing cavity for the proposed LHC luminosity upgrade. Knowledge of multipole field effects is important for accurate beam dynamics study of rf structures. The multipole components can be accurately determined numerically using the electromagnetic surface field data in the rf structure. This paper discusses the detailed analysis of those components for the fundamental deflecting/crabbing mode and higher order modes in the parallel-bar deflecting/crabbing cavity.

THPB063	Simulated Performance of the CARIBU EBIS Charge Breeder Transport Line	984
	C. Dickerson, S.A. Kondrashev, B. Mustapha, P.N. Ostroumov ANL, Argonne, USA
	Funding: This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract number DE-AC02-06CH11357. An Electron Beam Ion Source (EBIS) has been designed and is being built to charge breed ions from the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) for post acceleration in the Argonne Tandem Linear Accelerator System (ATLAS). The calculated transverse acceptance of the EBIS charge breeder can approach the emittance of the injected ion beam, so beam distortion during transport could lead to incomplete injection and a decrease in the overall system efficiency. The beam quality can be maintained for simulations of the transport line using the ideal ion beam parameters. This paper reports the results of the electrostatic and ion beam transport simulations used to minimize the ion beam distortions by optimizing component designs and configurations.

THPB064	Beam Dynamics Tools for Linacs Design	987
	A.S. Setty THALES, Colombes, France
	In the last 25 years, we have been using our in house 3D code PRODYN * for electron beam simulations. We have also been using our in house code SECTION for the design of the travelling wave accelerating structures and the beam loading compensation. PRODYN follows in time, the most complicated electron trajectories with relativistic space-charge effects. This code includes backward as well as forwards movements. This paper will describe those two codes and will give some simulations and measurements results. * D. Tronc and A. Setty, Electrons RF auto-focusing and capture in bunchers, Linear Accelerator Conference 1988, Virginia.