IPAC2012 - List of Keywords (higher-order-mode)

Paper	Title	Other Keywords	Page
MOPPC062	Eigenmode Computation for Cavities with Perturbed Geometry Based on a Series Expansion of Unperturbed Eigenmodes	cavity, HOM, factory, wakefield	277
	K. Brackebusch, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: Work supported by Federal Ministry for Research and Education BMBF under contracts 05H09HR5 and 05K10HRC. The geometry of an accelerator cavity determines its eigenmodes and thereby its performance characteristics. Therefore, accelerating performance and wakefield characteristics may be improved by an intentional modification of the geometry. However, undesired geometry perturbations due to manufacturing tolerances and operational demands can likewise impair it. To analyze the effects of geometry variations on the eigenmodes, parameter studies are to be undertaken. Using common eigenmode solvers it usually is necessary to perform a full eigenmode computation for each variation step, even if the geometry is only slightly altered. Parameter studies for cavity perturbations thus tend to be computationally extensive and inefficient. In this paper, we present the fundamentals of an efficient eigenmode computation method for varying cavity geometries. Knowing a set of initial eigenmodes of an unperturbed geometry, the method allows expanding the eigenmodes of any geometry that is part of the unperturbed one as a series of the initial eigenmodes. Thereby the computation effort may be significantly reduced. The method is demonstrated by means of analytically evaluable cavity geometries.

TUPPR025	Higher-Order Modes and Beam Loading Compensation in CLIC Main Linac	impedance, coupling, beam-loading, HOM	1867
	O. Kononenko, A. Grudiev CERN, Geneva, Switzerland
	Compensation of transient beam loading is one of the major performance issues of the future compact linear collider (CLIC). Recent calculations, which consider only the most important fundamental mode, have shown that the 0.03% limit on the rms relative bunch-to-bunch energy spread in the main beam can be reached by optimizing the RF power pulse shape for the TD26, the CLIC baseline accelerating structure. Here, using HFSS and massively parallel ACE3P codes developed at SLAC, we perform an additional dedicated study of the influence of higher-order modes on the energy spread compensation scheme. It is shown that taking these modes into account in the accelerating structure does not increase the rms energy spread in the main beam above the CLIC specification level. Results of the HFSS and ACE3P simulations are also in a good agreement.

TUPPR037	Simulations of Higher Order Modes in the ACC39 Module of FLASH	cavity, HOM, dipole, simulation	1900
	I.R.R. Shinton, R.M. Jones, P. Zhang UMAN, Manchester, United Kingdom Z. Li SLAC, Menlo Park, California, USA
	This study is primarily focused on the dipole component of the multiband expansion of the wakefield, with the emphasis being on the development of a HOM-based BPM system for ACC39 currently installed and in operation at FLASH and due to be installed at XFEL . Coupled inter-cavity modes are simulated together with a limited band of trapped modes. A suite of finite element computer codes (including HFSS and ACE3P) and globalised scattering matrix calculations (GSM) are used to investigate the modes in these cavities. In this way the nature of the multi-cavity nature of these modules is investigated with implications for a HOM-based BPM system and direct comparison to experimental results.

WEPPC027	A Quarter Wave Design for Crab Crossing in the LHC	cavity, HOM, acceleration, high-voltage	2260
	R. Calaga CERN, Geneva, Switzerland S.A. Belomestnykh, I. Ben-Zvi, Q. Wu BNL, Upton, Long Island, New York, USA
	Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP). The aperture constraints of the LHC interaction region and the alternating crossing schemes at two collision points calls for a superconducting deflecting cavity with very compact dimensions at low frequencies for the purpose of crab crossing. A new concept of using a superconducting 1/4-wave design, ideally suited to address the LHC constraints at 400 MHz, is proposed. The optimized RF cavity design and associated advantages of using a 1/4 wave resonator are presented. Aspects related to higher order mode damping, multipacting and frequency tuning are also addressed.

WEPPC053	SSR1 HOM Analysis and Measurements	HOM, dipole, quadrupole, cavity	2333
	M.H. Awida, P. Berrutti, I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE Single spoke resonators (SSR1, β=0.22) are currently under development for Project X at Fermilab. In this paper, extensive Higher Order Mode (HOM) analysis carried out on SSR1 is reported including the simulated R/Q for monopoles, dipoles, and quadrupoles. HOM measurements carried out on several spoke cavities are also reported including the harmonic response and the bead pull measurements. Comparison between the measured R/Q values and the simulated ones are presented.

WEPPC074	HOM Studies on the Cornell ERL Prototype Cavity in a Horizontal Test Cryomodule	cavity, HOM, linac, simulation	2384
	N.R.A. Valles, M.G. Billing, G.H. Hoffstaetter, M. Liepe, C.E. Mayes CLASSE, Ithaca, New York, USA
	The main linac 7-cell cavity for Cornell's Energy Recovery Linac was optimized to maximize threshold current through the ERL. This was achieved by designing center and end cells that reduce the strength of dipole higher-order modes. A prototype cavity was fabricated based on the optimized RF design and found to meet fundamental mode specifications in a vertical test. The higher-order-mode spectrum was measured when the cavity was installed in a horizontal test cryomodule and is compared to 2D and 3D EM simulations.

WEPPC103	Development of Spoke Cavities for High-velocity Applications	electron, cavity, multipole, impedance	2456
	C.S. Hopper, J.R. Delayen ODU, Norfolk, Virginia, USA R.G. Olave Old Dominion University, Norfolk, Virginia, USA
	In response to recent interest in alternatives to elliptical cavities for low-frequency, high-velocity applications we have initiated a program for the development of multi-spoke superconducting cavities. We have completed the electromagnetic design for two-spoke cavities operating at 352 and 325 MHz and a design velocity of β = 0.82 and β = 1. We present the results of the optimization, higher order mode (HOM) analysis, multipacting analysis, and an initial multipole expansion study of the fundamental accelerating mode.

WEPPC110	3D Simulations of Multipacting in the 56 MHz SRF Cavity	simulation, cavity, HOM, electron	2477
	Q. Wu, S.A. Belomestnykh BNL, Upton, Long Island, New York, USA L. Ge, C. Ko, Z. Li, C.-K. Ng, L. Xiao SLAC, Menlo Park, California, USA
	Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. The 56 MHz SRF Quarter-Wave Resonator (QWR) is designed for RHIC as a storage cavity to improve the collider performance. 2D multipacting simulation has been done for the cavity alone. Ripples were added to the outer body of the cavity for multipacting suppression based on the simulation findings. During operation, there will be four higher order mode (HOM) couplers and a fundamental power coupler (FPC) inserted through the end ports of the cavity and a fundamental mode damper (FD) inserted through a special port on the outer body. All of these components will be exposed to high RF fields. In this presentation we compare 2D and 3D codes simulation results for multipacting in the cavity. We also report 3D simulation results for multipacting simulation at the couplers.

WEPPC113	Progress on the High-Current 704 MHz Superconducting RF Cavity at BNL	cavity, HOM, damping, impedance	2486
	W. Xu, S.A. Belomestnykh, I. Ben-Zvi, H. Hahn, P. Jain BNL, Upton, Long Island, New York, USA C.M. Astefanous, M.D. Cole, J.P. Deacutis, D. Holmes AES, Medford, NY, USA
	Funding: This work was supported by Sotny Brook under contract No. DE-SC0002496 and Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. The 704 MHz high current superconducting cavity has been designed with consideration of both performance of fundamental mode and damping of higher order modes. A copper prototype cavity was fabricated by AES and delivered to BNL. RF measurements were carried out on this prototype cavity, including fundamental pass-band and HOM spectrum measurements, HOM studies using bead-pull setup, prototyping of antenna-type HOM couplers. The measurements show that the cavity has very good damping for the higher-order modes, which was one of the main goals for the high current cavity design. 3D cavity models were simulated with Omega3P code developed by SLAC to compare with the measurements. The paper describes the cavity design, RF measurement setups for the copper prototype, and presents comparison of the experimental results with computer simulations. The progress with the niobium cavity fabrication will also be described.

WEPPD017	Development of a New RF Finger Concept for Vacuum Beam Line Interconnections	vacuum, impedance, linac, simulation	2531
	C. Garion, A. Lacroix, H. Rambeau CERN, Geneva, Switzerland
	RF contact fingers are primarily used as a transition element to absorb the thermal expansion of vacuum chambers during bake-out and also to compensate for mechanical tolerances. They have to carry the beam image current to avoid the generation of Higher Order Modes and to reduce beam impedances. They are usually made out of copper beryllium thin sheets and are therefore very fragile and critical components. In this paper, a robust design based on a deformable finger concept is proposed. It allows the compensation of large longitudinal movements and also defaults such as transverse offset, twist or bending. The concept of this new RF fingers is first explained, then the design of the component is presented. The mechanical study based on a highly non linear Finite Element model is shown as well as preliminary tests, including fatigue assessment, carried out on prototypes.

WEPPP033	Design of a Wakefield Experiment in a Traveling-wave Photonic Band Gap Accelerating Structure	wakefield, electron, target, HOM	2798
	E.I. Simakov, R.L. Edwards LANL, Los Alamos, New Mexico, USA
	Funding: This work is supported by the U.S. Department of Energy (DOE) Office of Science Early Career Research Program. We designed an experiment to conduct a thorough investigation of higher order mode spectrum in a room-temperature traveling-wave photonic band gap (PBG) accelerating structure at 11.7 GHz. It has been long recognized that PBG structures have great potential in reducing long-range wakefields in accelerators. The first ever demonstration of acceleration in room-temperature PBG structures was conducted at MIT in 2005. Since then, the importance of that device has been recognized by many research institutions. However, the full experimental characterization of the wakefield spectrum in a beam test has not been performed to date. The Argonne Wakefield Accelerator (AWA) test facility at the Argonne National Laboratory represents a perfect site where this evaluation could be conducted with a single high charge electron bunch and with a train of bunches. We present the design of the accelerating structure that will be tested at AWA in the near future. The structure will consist of sixteen 2pi/3 PBG cells, including two coupler cells. We will also present the results of the initial cold-testing of the few sample cells and a plan for the beam test.

WEPPP035	Pushing the Gradient Limitations of Superconducting Photonic Band Gap Structure Cells	SRF, HOM, wakefield, electron	2801
	E.I. Simakov, W.B. Haynes, S.S. Kurennoy, J.F. O'Hara, E.R. Olivas, D.Y. Shchegolkov LANL, Los Alamos, New Mexico, USA
	Funding: This work is supported by the Department of Defense High Energy Laser Joint Technology Office through the Office of Naval Research. We present a design of a superconducting photonic band gap (PBG) accelerator cell operating at 2.1 GHz. The cell is designed with the PBG rods that are specially shaped to reduce the peak magnetic fields and at the same time to preserve its effectiveness for suppression of the higher order modes (HOMs). It has been long recognized that PBG structures have great potential in reducing and even completely eliminating HOMs in accelerators. This is especially beneficial for superconducting electron accelerators for high power free-electron lasers (FELs), which are intended to provide high current continuous duty electron beams. Using PBG structures to reduce the prominent beam-breakup phenomena due to HOMs will allow significantly increased beam-breakup thresholds, and consequently will allow the increase of the frequency of SRF accelerators and the development of novel compact high-current accelerator modules for FELs. High gradient limitations of PBG resonators and the optimal arrangement of the wakefield couplers will be discussed in details in this presentation.

FRXAA02	Advanced Solid State Lasers are Merging with Accelerators	laser, cavity, acceleration, alignment	4157
	A. Tünnermann, J. Limpert Friedrich Schiller Universität, Jena, Germany T. Schreiber Fraunhofer-Institute for Applied Optics and Precision Engineering, Jena, Germany
	In recent years, lasers have been developed to an essential tool in accelerator science, for acceleration and diagnostics. Novel applications require for high average power lasers in continuous and pulsed operation with diffraction limited beam quality. Lasers are known as sophisticated systems with a notorious poor efficiency. Most recently, rare-earth-doped fibers have established themselves as an attractive and power scalable solid-state laser concept. Using advanced large mode area fibers, in continuous-wave operation output powers in the 10 kW-regime with diffraction-limited beam quality at electrical to optical efficiencies of 30 percent have been demonstrated. In the pulsed regime average powers of the order of 1 kW even for femtosecond fiber laser systems have been reported. Coherent beam combination of these lasers allows for the generation of high peak power pulses at high repetition rates and output powers. In this contribution the state of the art in solid state laser technology operating at high average powers with inherent high efficiencies is reviewed. The prospects for future developments that will meet the demands set by the accelerator community will be discussed.
	Slides FRXAA02 [11.729 MB]

Paper

Title

Other Keywords

Page

MOPPC062

Eigenmode Computation for Cavities with Perturbed Geometry Based on a Series Expansion of Unperturbed Eigenmodes

cavity, HOM, factory, wakefield

277

K. Brackebusch, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

Funding: Work supported by Federal Ministry for Research and Education BMBF under contracts 05H09HR5 and 05K10HRC.
The geometry of an accelerator cavity determines its eigenmodes and thereby its performance characteristics. Therefore, accelerating performance and wakefield characteristics may be improved by an intentional modification of the geometry. However, undesired geometry perturbations due to manufacturing tolerances and operational demands can likewise impair it. To analyze the effects of geometry variations on the eigenmodes, parameter studies are to be undertaken. Using common eigenmode solvers it usually is necessary to perform a full eigenmode computation for each variation step, even if the geometry is only slightly altered. Parameter studies for cavity perturbations thus tend to be computationally extensive and inefficient. In this paper, we present the fundamentals of an efficient eigenmode computation method for varying cavity geometries. Knowing a set of initial eigenmodes of an unperturbed geometry, the method allows expanding the eigenmodes of any geometry that is part of the unperturbed one as a series of the initial eigenmodes. Thereby the computation effort may be significantly reduced. The method is demonstrated by means of analytically evaluable cavity geometries.

TUPPR025

Higher-Order Modes and Beam Loading Compensation in CLIC Main Linac

impedance, coupling, beam-loading, HOM

1867

O. Kononenko, A. Grudiev
CERN, Geneva, Switzerland

Compensation of transient beam loading is one of the major performance issues of the future compact linear collider (CLIC). Recent calculations, which consider only the most important fundamental mode, have shown that the 0.03% limit on the rms relative bunch-to-bunch energy spread in the main beam can be reached by optimizing the RF power pulse shape for the TD26, the CLIC baseline accelerating structure. Here, using HFSS and massively parallel ACE3P codes developed at SLAC, we perform an additional dedicated study of the influence of higher-order modes on the energy spread compensation scheme. It is shown that taking these modes into account in the accelerating structure does not increase the rms energy spread in the main beam above the CLIC specification level. Results of the HFSS and ACE3P simulations are also in a good agreement.

TUPPR037

Simulations of Higher Order Modes in the ACC39 Module of FLASH

cavity, HOM, dipole, simulation

1900

I.R.R. Shinton, R.M. Jones, P. Zhang
UMAN, Manchester, United Kingdom
Z. Li
SLAC, Menlo Park, California, USA

This study is primarily focused on the dipole component of the multiband expansion of the wakefield, with the emphasis being on the development of a HOM-based BPM system for ACC39 currently installed and in operation at FLASH and due to be installed at XFEL . Coupled inter-cavity modes are simulated together with a limited band of trapped modes. A suite of finite element computer codes (including HFSS and ACE3P) and globalised scattering matrix calculations (GSM) are used to investigate the modes in these cavities. In this way the nature of the multi-cavity nature of these modules is investigated with implications for a HOM-based BPM system and direct comparison to experimental results.

WEPPC027

A Quarter Wave Design for Crab Crossing in the LHC

cavity, HOM, acceleration, high-voltage

2260

R. Calaga
CERN, Geneva, Switzerland
S.A. Belomestnykh, I. Ben-Zvi, Q. Wu
BNL, Upton, Long Island, New York, USA

Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
The aperture constraints of the LHC interaction region and the alternating crossing schemes at two collision points calls for a superconducting deflecting cavity with very compact dimensions at low frequencies for the purpose of crab crossing. A new concept of using a superconducting 1/4-wave design, ideally suited to address the LHC constraints at 400 MHz, is proposed. The optimized RF cavity design and associated advantages of using a 1/4 wave resonator are presented. Aspects related to higher order mode damping, multipacting and frequency tuning are also addressed.

WEPPC053

SSR1 HOM Analysis and Measurements

HOM, dipole, quadrupole, cavity

2333

M.H. Awida, P. Berrutti, I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
Single spoke resonators (SSR1, β=0.22) are currently under development for Project X at Fermilab. In this paper, extensive Higher Order Mode (HOM) analysis carried out on SSR1 is reported including the simulated R/Q for monopoles, dipoles, and quadrupoles. HOM measurements carried out on several spoke cavities are also reported including the harmonic response and the bead pull measurements. Comparison between the measured R/Q values and the simulated ones are presented.

WEPPC074

HOM Studies on the Cornell ERL Prototype Cavity in a Horizontal Test Cryomodule

cavity, HOM, linac, simulation

2384

N.R.A. Valles, M.G. Billing, G.H. Hoffstaetter, M. Liepe, C.E. Mayes
CLASSE, Ithaca, New York, USA

The main linac 7-cell cavity for Cornell's Energy Recovery Linac was optimized to maximize threshold current through the ERL. This was achieved by designing center and end cells that reduce the strength of dipole higher-order modes. A prototype cavity was fabricated based on the optimized RF design and found to meet fundamental mode specifications in a vertical test. The higher-order-mode spectrum was measured when the cavity was installed in a horizontal test cryomodule and is compared to 2D and 3D EM simulations.

WEPPC103

Development of Spoke Cavities for High-velocity Applications

electron, cavity, multipole, impedance

2456

C.S. Hopper, J.R. Delayen
ODU, Norfolk, Virginia, USA
R.G. Olave
Old Dominion University, Norfolk, Virginia, USA

In response to recent interest in alternatives to elliptical cavities for low-frequency, high-velocity applications we have initiated a program for the development of multi-spoke superconducting cavities. We have completed the electromagnetic design for two-spoke cavities operating at 352 and 325 MHz and a design velocity of β = 0.82 and β = 1. We present the results of the optimization, higher order mode (HOM) analysis, multipacting analysis, and an initial multipole expansion study of the fundamental accelerating mode.

WEPPC110

3D Simulations of Multipacting in the 56 MHz SRF Cavity

simulation, cavity, HOM, electron

2477

Q. Wu, S.A. Belomestnykh
BNL, Upton, Long Island, New York, USA
L. Ge, C. Ko, Z. Li, C.-K. Ng, L. Xiao
SLAC, Menlo Park, California, USA

Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The 56 MHz SRF Quarter-Wave Resonator (QWR) is designed for RHIC as a storage cavity to improve the collider performance. 2D multipacting simulation has been done for the cavity alone. Ripples were added to the outer body of the cavity for multipacting suppression based on the simulation findings. During operation, there will be four higher order mode (HOM) couplers and a fundamental power coupler (FPC) inserted through the end ports of the cavity and a fundamental mode damper (FD) inserted through a special port on the outer body. All of these components will be exposed to high RF fields. In this presentation we compare 2D and 3D codes simulation results for multipacting in the cavity. We also report 3D simulation results for multipacting simulation at the couplers.

WEPPC113

Progress on the High-Current 704 MHz Superconducting RF Cavity at BNL

cavity, HOM, damping, impedance

2486

W. Xu, S.A. Belomestnykh, I. Ben-Zvi, H. Hahn, P. Jain
BNL, Upton, Long Island, New York, USA
C.M. Astefanous, M.D. Cole, J.P. Deacutis, D. Holmes
AES, Medford, NY, USA

Funding: This work was supported by Sotny Brook under contract No. DE-SC0002496 and Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The 704 MHz high current superconducting cavity has been designed with consideration of both performance of fundamental mode and damping of higher order modes. A copper prototype cavity was fabricated by AES and delivered to BNL. RF measurements were carried out on this prototype cavity, including fundamental pass-band and HOM spectrum measurements, HOM studies using bead-pull setup, prototyping of antenna-type HOM couplers. The measurements show that the cavity has very good damping for the higher-order modes, which was one of the main goals for the high current cavity design. 3D cavity models were simulated with Omega3P code developed by SLAC to compare with the measurements. The paper describes the cavity design, RF measurement setups for the copper prototype, and presents comparison of the experimental results with computer simulations. The progress with the niobium cavity fabrication will also be described.

WEPPD017

Development of a New RF Finger Concept for Vacuum Beam Line Interconnections

vacuum, impedance, linac, simulation

2531

C. Garion, A. Lacroix, H. Rambeau
CERN, Geneva, Switzerland

RF contact fingers are primarily used as a transition element to absorb the thermal expansion of vacuum chambers during bake-out and also to compensate for mechanical tolerances. They have to carry the beam image current to avoid the generation of Higher Order Modes and to reduce beam impedances. They are usually made out of copper beryllium thin sheets and are therefore very fragile and critical components. In this paper, a robust design based on a deformable finger concept is proposed. It allows the compensation of large longitudinal movements and also defaults such as transverse offset, twist or bending. The concept of this new RF fingers is first explained, then the design of the component is presented. The mechanical study based on a highly non linear Finite Element model is shown as well as preliminary tests, including fatigue assessment, carried out on prototypes.

WEPPP033

Design of a Wakefield Experiment in a Traveling-wave Photonic Band Gap Accelerating Structure

wakefield, electron, target, HOM

2798

E.I. Simakov, R.L. Edwards
LANL, Los Alamos, New Mexico, USA

Funding: This work is supported by the U.S. Department of Energy (DOE) Office of Science Early Career Research Program.
We designed an experiment to conduct a thorough investigation of higher order mode spectrum in a room-temperature traveling-wave photonic band gap (PBG) accelerating structure at 11.7 GHz. It has been long recognized that PBG structures have great potential in reducing long-range wakefields in accelerators. The first ever demonstration of acceleration in room-temperature PBG structures was conducted at MIT in 2005. Since then, the importance of that device has been recognized by many research institutions. However, the full experimental characterization of the wakefield spectrum in a beam test has not been performed to date. The Argonne Wakefield Accelerator (AWA) test facility at the Argonne National Laboratory represents a perfect site where this evaluation could be conducted with a single high charge electron bunch and with a train of bunches. We present the design of the accelerating structure that will be tested at AWA in the near future. The structure will consist of sixteen 2pi/3 PBG cells, including two coupler cells. We will also present the results of the initial cold-testing of the few sample cells and a plan for the beam test.

WEPPP035

Pushing the Gradient Limitations of Superconducting Photonic Band Gap Structure Cells

SRF, HOM, wakefield, electron

2801

E.I. Simakov, W.B. Haynes, S.S. Kurennoy, J.F. O'Hara, E.R. Olivas, D.Y. Shchegolkov
LANL, Los Alamos, New Mexico, USA

Funding: This work is supported by the Department of Defense High Energy Laser Joint Technology Office through the Office of Naval Research.
We present a design of a superconducting photonic band gap (PBG) accelerator cell operating at 2.1 GHz. The cell is designed with the PBG rods that are specially shaped to reduce the peak magnetic fields and at the same time to preserve its effectiveness for suppression of the higher order modes (HOMs). It has been long recognized that PBG structures have great potential in reducing and even completely eliminating HOMs in accelerators. This is especially beneficial for superconducting electron accelerators for high power free-electron lasers (FELs), which are intended to provide high current continuous duty electron beams. Using PBG structures to reduce the prominent beam-breakup phenomena due to HOMs will allow significantly increased beam-breakup thresholds, and consequently will allow the increase of the frequency of SRF accelerators and the development of novel compact high-current accelerator modules for FELs. High gradient limitations of PBG resonators and the optimal arrangement of the wakefield couplers will be discussed in details in this presentation.

FRXAA02

Advanced Solid State Lasers are Merging with Accelerators

laser, cavity, acceleration, alignment

4157

A. Tünnermann, J. Limpert
Friedrich Schiller Universität, Jena, Germany
T. Schreiber
Fraunhofer-Institute for Applied Optics and Precision Engineering, Jena, Germany

In recent years, lasers have been developed to an essential tool in accelerator science, for acceleration and diagnostics. Novel applications require for high average power lasers in continuous and pulsed operation with diffraction limited beam quality. Lasers are known as sophisticated systems with a notorious poor efficiency. Most recently, rare-earth-doped fibers have established themselves as an attractive and power scalable solid-state laser concept. Using advanced large mode area fibers, in continuous-wave operation output powers in the 10 kW-regime with diffraction-limited beam quality at electrical to optical efficiencies of 30 percent have been demonstrated. In the pulsed regime average powers of the order of 1 kW even for femtosecond fiber laser systems have been reported. Coherent beam combination of these lasers allows for the generation of high peak power pulses at high repetition rates and output powers. In this contribution the state of the art in solid state laser technology operating at high average powers with inherent high efficiencies is reviewed. The prospects for future developments that will meet the demands set by the accelerator community will be discussed.

Slides FRXAA02 [11.729 MB]