2011 Particle Accelerator Conference - List of Authors (Dragt, A.)

Paper

Title

Page

Accurate Computation of Transfer Maps for Realistic Beamline Elements from Surface Data

742

C.E. Mitchell
NRL, Washington, DC, USA
A. Dragt
UMD, College Park, Maryland, USA

The behavior of orbits in charged-particle beam transport systems, including both linear and circular accelerators as well as final focus sections and spectrometers, can depend sensitively on nonlinear fringe-field and high-order-multipole effects in the various beam-line elements. The inclusion of these effects requires a detailed and realistic model of the interior and fringe fields, including their high spatial derivatives. A collection of surface fitting methods has been developed for extracting this information accurately from 3-dimensional field data on a grid, as provided by various 3-dimensional finite-element field codes. Based on these realistic field models, Lie or other methods may be used to compute accurate design orbits and accurate transfer maps about these orbits. This talk will provide a description of the methods along with example applications. An exactly-soluble but numerically challenging model field is used to provide a rigorous collection of performance benchmarks.

Slides TUOCN1 [1.630 MB]

TUOCN3

Application of the Eigen-Emittance Concept to Design Ultra-Bright Electron Beams

752

L.D. Duffy, K. Bishofberger, B.E. Carlsten, S.J. Russell, N.A. Yampolsky
LANL, Los Alamos, New Mexico, USA
A. Dragt
UMD, College Park, Maryland, USA
R.D. Ryne
LBNL, Berkeley, California, USA

Funding: We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program.
Using correlations at the cathode to tailor the beam’s eigen-emittances is a recent concept made useful by the symplectic nature of Hamiltonian systems. While introducing correlations does not change the overall 6-dimensional phase space volume, it can change the partitioning of this volume into the longitudinal and two transverse emittances, which become the eigen-emittances if the initial correlations are removed. In principle, this technique can be used to generate beams with highly asymmetric emittances, such as those needed for the next generation of very hard X-ray free-electron lasers. Based on linear correlations, the applicability of this approach is limited by the magnitude of nonlinear effects in photoinjectors. We review the eigen-emittance concept and present a linear eigen-emittance design leading to a highly partitioned, and transversely ultra-bright, electron beam. We also present numerical tools to examine the evolution of the eigen-emittances in realistic accelerator structures and results indicating how much partitioning is practical.

Slides TUOCN3 [0.530 MB]

Paper	Title	Page
TUOCN1	Accurate Computation of Transfer Maps for Realistic Beamline Elements from Surface Data	742
	C.E. Mitchell NRL, Washington, DC, USA A. Dragt UMD, College Park, Maryland, USA
	The behavior of orbits in charged-particle beam transport systems, including both linear and circular accelerators as well as final focus sections and spectrometers, can depend sensitively on nonlinear fringe-field and high-order-multipole effects in the various beam-line elements. The inclusion of these effects requires a detailed and realistic model of the interior and fringe fields, including their high spatial derivatives. A collection of surface fitting methods has been developed for extracting this information accurately from 3-dimensional field data on a grid, as provided by various 3-dimensional finite-element field codes. Based on these realistic field models, Lie or other methods may be used to compute accurate design orbits and accurate transfer maps about these orbits. This talk will provide a description of the methods along with example applications. An exactly-soluble but numerically challenging model field is used to provide a rigorous collection of performance benchmarks.
	Slides TUOCN1 [1.630 MB]

TUOCN3	Application of the Eigen-Emittance Concept to Design Ultra-Bright Electron Beams	752
	L.D. Duffy, K. Bishofberger, B.E. Carlsten, S.J. Russell, N.A. Yampolsky LANL, Los Alamos, New Mexico, USA A. Dragt UMD, College Park, Maryland, USA R.D. Ryne LBNL, Berkeley, California, USA
	Funding: We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program. Using correlations at the cathode to tailor the beam’s eigen-emittances is a recent concept made useful by the symplectic nature of Hamiltonian systems. While introducing correlations does not change the overall 6-dimensional phase space volume, it can change the partitioning of this volume into the longitudinal and two transverse emittances, which become the eigen-emittances if the initial correlations are removed. In principle, this technique can be used to generate beams with highly asymmetric emittances, such as those needed for the next generation of very hard X-ray free-electron lasers. Based on linear correlations, the applicability of this approach is limited by the magnitude of nonlinear effects in photoinjectors. We review the eigen-emittance concept and present a linear eigen-emittance design leading to a highly partitioned, and transversely ultra-bright, electron beam. We also present numerical tools to examine the evolution of the eigen-emittances in realistic accelerator structures and results indicating how much partitioning is practical.
	Slides TUOCN3 [0.530 MB]