SRF2013 - List of Keywords (wakefield)

Paper	Title	Other Keywords	Page
MOP092	Computation of Wakefields and HOM Port Signals by Means of Reduced Order Models	impedance, cavity, HOM, operation	364
	J. Heller, T. Flisgen, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	The investigation of wakefields is an important task in the design and operation of particle accelerators. Computer simulations are a reliable tool to extend the understanding of these effects. This contribution presents an application example of a new method to compute wakefields as well as parameters derived from those fields, such as higher order mode (HOM) port signals. The method is based on a reduced order model of the structure created by as set of 3D eigenmodes, a set of 2D waveguide port modes and the current density of the beam. In contrast to other wakefield computations, the proposed method operates directly on the reduced order model. Therefore, once having established this model, the beam-excited fields can be determined quickly for different beam parameters. As a matter of fact, only a small part of the reduced system has to be recomputed for every sweep point. From these advantages it is obvious, that the method is highly compatible for beam parameter studies. In a proof of principal the effectiveness of the method compared to established methods of wakefield computations in terms of computational time and accuracy is shown.

MOP093	Geometric Optics of Wake Fields of Very Short Bunches in Superconducting Cavities	cavity, HOM, FEL, superconducting-cavity	367
	A. Novokhatski SLAC, Menlo Park, California, USA
	Funding: Work supported by Department of Energy contract DE-AC02-76SF00515 We study the wake potentials of very short bunches in a quasi periodic structure of superconducting cavities. We analyze the pattern of the electric force lines and the shape of a cavity. The behavior of electric force lines reflects irregularities of the shape structure of a cavity. Simulations were carried for different kind of cavities, including JLAB 7 cell cavity with application to future light sources.

THIOC03	Superconducting Photonic Band Gap Structures for High-Current Applications	cavity, SRF, HOM, accelerating-gradient	860
	E.I. Simakov, S. Arsenyev, W.B. Haynes, S.S. Kurennoy, D.Y. Shchegolkov, N.A. Suvorova, T. Tajima LANL, Los Alamos, New Mexico, USA C.H. Boulware, T.L. Grimm Niowave, Inc., Lansing, Michigan, USA
	Funding: This work is supported in parts by the U.S. DOE Early Career Research Program and by the DOD High Energy Laser Joint Technology Office through the Office of Naval Research. We present the results of recent design and testing of several 2.1 GHz superconducting rf (SRF) photonic band gap (PBG) resonators. PBG cells have great potential for outcoupling long-range wakefields in SRF accelerator structures without affecting the fundamental accelerating mode. Using PBG structures in superconducting particle accelerators will allow operation at higher frequencies and moving forward to significantly higher beam luminosities thus leading towards a completely new generation of colliders for high energy physics. Here we report the results of our efforts to fabricate 2.1 GHz PBG cells with round and elliptical rods and to test them with high power at liquid helium temperatures. Two PBG cells with round rods were tested in spring of 2012 and achieved accelerating gradients of 15 MV/m at 2 Kelvin. Two PBG cells with elliptical rods will be tested in summer of 2013.
	Slides THIOC03 [2.284 MB]

Paper

Title

Other Keywords

Page

MOP092

Computation of Wakefields and HOM Port Signals by Means of Reduced Order Models

impedance, cavity, HOM, operation

364

J. Heller, T. Flisgen, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

The investigation of wakefields is an important task in the design and operation of particle accelerators. Computer simulations are a reliable tool to extend the understanding of these effects. This contribution presents an application example of a new method to compute wakefields as well as parameters derived from those fields, such as higher order mode (HOM) port signals. The method is based on a reduced order model of the structure created by as set of 3D eigenmodes, a set of 2D waveguide port modes and the current density of the beam. In contrast to other wakefield computations, the proposed method operates directly on the reduced order model. Therefore, once having established this model, the beam-excited fields can be determined quickly for different beam parameters. As a matter of fact, only a small part of the reduced system has to be recomputed for every sweep point. From these advantages it is obvious, that the method is highly compatible for beam parameter studies. In a proof of principal the effectiveness of the method compared to established methods of wakefield computations in terms of computational time and accuracy is shown.

MOP093

Geometric Optics of Wake Fields of Very Short Bunches in Superconducting Cavities

cavity, HOM, FEL, superconducting-cavity

367

A. Novokhatski
SLAC, Menlo Park, California, USA

Funding: Work supported by Department of Energy contract DE-AC02-76SF00515
We study the wake potentials of very short bunches in a quasi periodic structure of superconducting cavities. We analyze the pattern of the electric force lines and the shape of a cavity. The behavior of electric force lines reflects irregularities of the shape structure of a cavity. Simulations were carried for different kind of cavities, including JLAB 7 cell cavity with application to future light sources.

THIOC03

Superconducting Photonic Band Gap Structures for High-Current Applications

cavity, SRF, HOM, accelerating-gradient

860

E.I. Simakov, S. Arsenyev, W.B. Haynes, S.S. Kurennoy, D.Y. Shchegolkov, N.A. Suvorova, T. Tajima
LANL, Los Alamos, New Mexico, USA
C.H. Boulware, T.L. Grimm
Niowave, Inc., Lansing, Michigan, USA

Funding: This work is supported in parts by the U.S. DOE Early Career Research Program and by the DOD High Energy Laser Joint Technology Office through the Office of Naval Research.
We present the results of recent design and testing of several 2.1 GHz superconducting rf (SRF) photonic band gap (PBG) resonators. PBG cells have great potential for outcoupling long-range wakefields in SRF accelerator structures without affecting the fundamental accelerating mode. Using PBG structures in superconducting particle accelerators will allow operation at higher frequencies and moving forward to significantly higher beam luminosities thus leading towards a completely new generation of colliders for high energy physics. Here we report the results of our efforts to fabricate 2.1 GHz PBG cells with round and elliptical rods and to test them with high power at liquid helium temperatures. Two PBG cells with round rods were tested in spring of 2012 and achieved accelerating gradients of 15 MV/m at 2 Kelvin. Two PBG cells with elliptical rods will be tested in summer of 2013.

Slides THIOC03 [2.284 MB]