FEL2011 - List of Keywords (extraction)

Paper	Title	Other Keywords	Page
MOPC09	Use of Re-Acceleration and Tapering in High Gain Free Electron Lasers to Enhance Power and Energy Extraction	FEL, undulator, electron, acceleration	115
	R. Dusad, G. Travish UCLA, Los Angeles, USA
	In high gain Free Electron Lasers (FELs), it is possible to use undulator tapering to increase power and energy extraction beyond saturation. For some applications, however, tapering is not sufficient or results in excessively long structures. Here we the study use of tapered undulators interrupted by short accelerator sections to increase the power extracted per unit length. Re-acceleration restores nominal energy to the beam with minimal disruption to bunching, and allows repeated use of a single taper profile. We show that for suitable parameter sets this approach can perform better than ideal tapering alone, and may serve to greatly improve and simplify high peak and average power FELs. Based on these findings, we propose a first experiment to test the re-acceleration with tapering concept.

THPB21	Extraction Arc for FLASH2	simulation, septum, emittance, electron	601
	M. Scholz, W. Decking, B. Faatz, T. Limberg DESY, Hamburg, Germany B. Liu SINAP, Shanghai, People's Republic of China
	FLASH2 is an extension of the existing FEL FLASH at DESY, Hamburg. It uses the same linear accelerator. A separate tunnel and a new experimental hall will be built next to the existing FLASH facilities. First constructions started in spring 2011. A fast kicker and a septum to be installed behind the last superconducting acceleration module give the possibility to distribute the beam to the existing beam line and to the new extraction arc. Within this arc a pulsed bending magnet allows to send the beam into two separate beam lines: One hosting undulators for SASE and space for HHG seeding (FLASH2), the other serving a proposed plasma wake field experiment or later on another FEL beam line (FLASH3). The extraction arc design has to fulfill specific requirements such as small emittance and energy spread growth. Furthermore, constrains are given by the existing FLASH buildings and by the space required for the in-coupling of the seed laser. Beam quality impairment has been mitigated by designing the beam optics with horizontal beam waists in all bending magnets. To optimize the extraction arc, simulations for different layouts were carried out using the programs ELEGANT and CSRTRACK.

Paper

Title

Other Keywords

Page

MOPC09

Use of Re-Acceleration and Tapering in High Gain Free Electron Lasers to Enhance Power and Energy Extraction

FEL, undulator, electron, acceleration

115

R. Dusad, G. Travish
UCLA, Los Angeles, USA

In high gain Free Electron Lasers (FELs), it is possible to use undulator tapering to increase power and energy extraction beyond saturation. For some applications, however, tapering is not sufficient or results in excessively long structures. Here we the study use of tapered undulators interrupted by short accelerator sections to increase the power extracted per unit length. Re-acceleration restores nominal energy to the beam with minimal disruption to bunching, and allows repeated use of a single taper profile. We show that for suitable parameter sets this approach can perform better than ideal tapering alone, and may serve to greatly improve and simplify high peak and average power FELs. Based on these findings, we propose a first experiment to test the re-acceleration with tapering concept.

THPB21

Extraction Arc for FLASH2

simulation, septum, emittance, electron

601

M. Scholz, W. Decking, B. Faatz, T. Limberg
DESY, Hamburg, Germany
B. Liu
SINAP, Shanghai, People's Republic of China

FLASH2 is an extension of the existing FEL FLASH at DESY, Hamburg. It uses the same linear accelerator. A separate tunnel and a new experimental hall will be built next to the existing FLASH facilities. First constructions started in spring 2011. A fast kicker and a septum to be installed behind the last superconducting acceleration module give the possibility to distribute the beam to the existing beam line and to the new extraction arc. Within this arc a pulsed bending magnet allows to send the beam into two separate beam lines: One hosting undulators for SASE and space for HHG seeding (FLASH2), the other serving a proposed plasma wake field experiment or later on another FEL beam line (FLASH3). The extraction arc design has to fulfill specific requirements such as small emittance and energy spread growth. Furthermore, constrains are given by the existing FLASH buildings and by the space required for the in-coupling of the seed laser. Beam quality impairment has been mitigated by designing the beam optics with horizontal beam waists in all bending magnets. To optimize the extraction arc, simulations for different layouts were carried out using the programs ELEGANT and CSRTRACK.