2011 Particle Accelerator Conference - List of Keywords (free-electron-laser)

Paper	Title	Other Keywords	Page
TUOCN3	Application of the Eigen-Emittance Concept to Design Ultra-Bright Electron Beams	emittance, electron, cathode, laser	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]

TUP039	Low Latency Data Transmission in LLRF Systems	LLRF, controls, alignment, feedback	877
	D.R. Makowski, G.W. Jabłoński, A. Napieralski, P. Predki TUL-DMCS, Łódź, Poland
	Funding: The research leading to these results has received funding from the Polish National Science Council Grant 642/N-TESLAXFEL/09/2010/0. The linear accelerators applied to drive Free Electron Lasers (FELs), such as the X-Ray Free Electron Laser (XFEL), require sophisticated control systems. The Low Level Radio Frequency (LLRF) control systems of a linear accelerator should provide signal to vector modulator in less than 1 microsecond. Therefore the latency of communication interfaces is more important than their throughput. The paper discusses the application of serial gigabit links for transmission of data in LLRF systems. The latency of pure serial transmission based on Xilinx RocketIO transceivers was evaluated and compared with Xilinx Aurora protocol. The developed low latency protocol will be also presented.

THP149	Amplification of Current Density Modulation in a FEL with an Infinite Electron beam	electron, FEL, radiation, laser	2399
	G. Wang, V. Litvinenko, S.D. Webb BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. We show that the paraxial field equation for a free electron laser (FEL) in an infinitely wide electron beam with a kappa-2 energy distribution can be reduced to a fourth ordinary differential equation (ODE). Its solution for arbitrary initial phase space density modulation has been derived in the wave-vector domain. For initial current modulation with Gaussian profile, close form solutions are obtained in space-time domain.

Paper

Title

Other Keywords

Page

TUOCN3

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

emittance, electron, cathode, laser

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]

TUP039

Low Latency Data Transmission in LLRF Systems

LLRF, controls, alignment, feedback

877

D.R. Makowski, G.W. Jabłoński, A. Napieralski, P. Predki
TUL-DMCS, Łódź, Poland

Funding: The research leading to these results has received funding from the Polish National Science Council Grant 642/N-TESLAXFEL/09/2010/0.
The linear accelerators applied to drive Free Electron Lasers (FELs), such as the X-Ray Free Electron Laser (XFEL), require sophisticated control systems. The Low Level Radio Frequency (LLRF) control systems of a linear accelerator should provide signal to vector modulator in less than 1 microsecond. Therefore the latency of communication interfaces is more important than their throughput. The paper discusses the application of serial gigabit links for transmission of data in LLRF systems. The latency of pure serial transmission based on Xilinx RocketIO transceivers was evaluated and compared with Xilinx Aurora protocol. The developed low latency protocol will be also presented.

THP149

Amplification of Current Density Modulation in a FEL with an Infinite Electron beam

electron, FEL, radiation, laser

2399

G. Wang, V. Litvinenko, S.D. Webb
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
We show that the paraxial field equation for a free electron laser (FEL) in an infinitely wide electron beam with a kappa-2 energy distribution can be reduced to a fourth ordinary differential equation (ODE). Its solution for arbitrary initial phase space density modulation has been derived in the wave-vector domain. For initial current modulation with Gaussian profile, close form solutions are obtained in space-time domain.