IPAC2015 - List of Authors (Weiland, T.)

Paper	Title	Page
MOPWA029	Investigations of the Space-Charge-Limited Emission in the L-Band E-Xfel Photoinjector at Desy-Pitz	162
	Y. Chen, H. De Gersem, E. Gjonaj, A.V. Tsakanian, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany C. Hernandez-Garcia JLab, Newport News, Virginia, USA M. Krasilnikov, F. Stephan DESY Zeuthen, Zeuthen, Germany
	Funding: work supported by DESY Hamburg and Zeuthen Sites This paper discusses the numerical modelling of electron bunch emission for an L-band normal conducting RF photogun. The main objective is clarifying the discrepancies between measurements and simulations performed for the European X-ray Free Electron Laser (E-XFEL) injector at DESY-PITZ. An iterative beam dynamics simulation procedure is proposed for the calculation of the total extracted bunch charge under the assumption that the emission source operates at the space-charge limit of the gun. This algorithm has been implemented in the three-dimensional full electromagnetic PIC Solver of the CST Particle Studio (CST-PS). Simulation results are in good agreements with measurements for a series of operation parameters. Further comparisons with a conventional Poisson-solver-based (PSB) tracking algorithm demonstrates the great significance of transient electromagnetic field effects for the beam dynamics in high brightness electron sources. Computer Simulation Technology AG, http://www.cst.com/
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA029
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MOPWA031	A New Approach for Resistive Wakefield Calculations in Time Domain	168
	A.V. Tsakanian, H. De Gersem, E. Gjonaj, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany M. Dohlus, I. Zagorodnov DESY, Hamburg, Germany
	We report on a new numerical technique for the computation of the wakefields excited by ultra-short bunches in the structures with walls of finite conductivity. The developed 3D numerical method is fully time domain. It is based on special Staggered Finite Volume Time Domain (SFVTD) method and has no numerical dispersion in all three axial directions simultaneously. This results in large saving in computational time as well as improved accuracy. The resistive boundary model applies Surface Impedance Boundary Condition (SIBC) evaluation in time domain and covers boundary effects like frequency dependent conductivity, surface roughness and metal oxidation. A good agreement between numerical simulation and perturbation theory is obtained. In addition the new method allows implementation of moving mesh approach that considerably reduces requirements on computational resources. The developed method is especially effective for short range resistive wakefield calculations excited by ultra-short bunches used in FEL based LINACs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA031
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Investigations of the Space-Charge-Limited Emission in the L-Band E-Xfel Photoinjector at Desy-Pitz

162

Y. Chen, H. De Gersem, E. Gjonaj, A.V. Tsakanian, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany
C. Hernandez-Garcia
JLab, Newport News, Virginia, USA
M. Krasilnikov, F. Stephan
DESY Zeuthen, Zeuthen, Germany

Funding: work supported by DESY Hamburg and Zeuthen Sites
This paper discusses the numerical modelling of electron bunch emission for an L-band normal conducting RF photogun. The main objective is clarifying the discrepancies between measurements and simulations performed for the European X-ray Free Electron Laser (E-XFEL) injector at DESY-PITZ. An iterative beam dynamics simulation procedure is proposed for the calculation of the total extracted bunch charge under the assumption that the emission source operates at the space-charge limit of the gun. This algorithm has been implemented in the three-dimensional full electromagnetic PIC Solver of the CST Particle Studio (CST-PS)*. Simulation results are in good agreements with measurements for a series of operation parameters. Further comparisons with a conventional Poisson-solver-based (PSB) tracking algorithm demonstrates the great significance of transient electromagnetic field effects for the beam dynamics in high brightness electron sources.
* Computer Simulation Technology AG, http://www.cst.com/

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPWA031

A New Approach for Resistive Wakefield Calculations in Time Domain

168

A.V. Tsakanian, H. De Gersem, E. Gjonaj, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany
M. Dohlus, I. Zagorodnov
DESY, Hamburg, Germany

We report on a new numerical technique for the computation of the wakefields excited by ultra-short bunches in the structures with walls of finite conductivity. The developed 3D numerical method is fully time domain. It is based on special Staggered Finite Volume Time Domain (SFVTD) method and has no numerical dispersion in all three axial directions simultaneously. This results in large saving in computational time as well as improved accuracy. The resistive boundary model applies Surface Impedance Boundary Condition (SIBC) evaluation in time domain and covers boundary effects like frequency dependent conductivity, surface roughness and metal oxidation. A good agreement between numerical simulation and perturbation theory is obtained. In addition the new method allows implementation of moving mesh approach that considerably reduces requirements on computational resources. The developed method is especially effective for short range resistive wakefield calculations excited by ultra-short bunches used in FEL based LINACs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA031

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)