FEL2011 - List of Authors (Faatz, B.)

Paper	Title	Page
MOPC05	HGHG Scheme for FLASH II	107
	A. Meseck, R. Mitzner HZB, Berlin, Germany W. Decking, B. Faatz, M. Scholz DESY, Hamburg, Germany
	FLASH II is a major extension of the existing FLASH facility at DESY. It has been proposed in collaboration with the HZB. FLASH II is a seeded FEL in the parameter range of FLASH. The final layout of the undulator section of FLASH II allows for different seeding schemes. So that seeding with an HHG source as well as seeding in cascaded HGHG scheme and several combination of these schemes are possible. However, for the shortest wavelengths down to 4 nm the cascaded HGHG scheme will be utilized. It consists of two frequency up conversion stages utilizing a Ti:Sa laser based seeding source in UVU range. We present and discuss start-to-end simulation studies for the shortest wavelength generated in the HGHG cascade of FLASH II.

TUPA22	FLASH II: A Project Update	247
	B. Faatz, V. Ayvazyan, N. Baboi, V. Balandin, W. Decking, S. Düsterer, H.-J. Eckoldt, M. Felber, J. Feldhaus, N. Golubeva, K. Honkavaara, M. Körfer, T. Laarmann, A. Leuschner, L. Lilje, T. Limberg, D. Nölle, F. Obier, A. Petrov, E. Plönjes, K. Rehlich, H. Schlarb, B. Schmidt, M. Schmitz, S. Schreiber, H. Schulte-Schrepping, J. Spengler, M. Staack, K.I. Tiedtke, M. Tischer, R. Treusch, M. Vogt, H.C. Weddig DESY, Hamburg, Germany J. Bahrdt, R. Follath, K. Holldack, A. Meseck, R. Mitzner HZB, Berlin, Germany J. Chen, H.X. Deng, B. Liu SINAP, Shanghai, People's Republic of China M. Drescher, A. Hage, V. Miltchev, R. Riedel, J. Rönsch-Schulenburg, J. Roßbach, M. Schulz, A. Willner Uni HH, Hamburg, Germany M. Gensch HZDR, Dresden, Germany F. Tavella HIJ, Jena, Germany
	FLASH II is an extension of the existing FLASH facility by an undulator line and an experimental Hall of which the construction will start before the end of the year. Aims are to increase beamtime for users and implement HHG seeding for the longer wavelength range from 10 to 40 nm at a reduced repetition rate of 100 kHz. Additional seeding schemes are under discussion as a future option. We will present a progress report of FLASH II.

TUPB04	Status of the FEL User Facility FLASH	267
	S. Schreiber, B. Faatz, J. Feldhaus, K. Honkavaara, R. Treusch, M. Vogt DESY, Hamburg, Germany
	The free-electron laser FLASH at DESY, Germany has been upgraded in 2010 and extended its wavelength range down to 4.1 nm. Beside the increased electron beam energy to 1.25 GeV, an other important upgrade is the installation of 3.9 GHz superconducting RF cavities in the injector. They are used to shape the longitudinal electron beam phase space. Now, significantly more FEL radiation energy per pulse of up to several hundreds of microjoules are achieved. Moreover, the system allows to adjust the FEL pulse length, from long pulses of more than 200 fs to short pulses well below 50 fs. The upgraded FLASH facility shows an excellent performance in terms of FEL radiation quality and stability as well as in reliability of operation. The 3rd user period started as scheduled in September 2010.

THPB21	Extraction Arc for FLASH2	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

Page

HGHG Scheme for FLASH II

107

A. Meseck, R. Mitzner
HZB, Berlin, Germany
W. Decking, B. Faatz, M. Scholz
DESY, Hamburg, Germany

FLASH II is a major extension of the existing FLASH facility at DESY. It has been proposed in collaboration with the HZB. FLASH II is a seeded FEL in the parameter range of FLASH. The final layout of the undulator section of FLASH II allows for different seeding schemes. So that seeding with an HHG source as well as seeding in cascaded HGHG scheme and several combination of these schemes are possible. However, for the shortest wavelengths down to 4 nm the cascaded HGHG scheme will be utilized. It consists of two frequency up conversion stages utilizing a Ti:Sa laser based seeding source in UVU range. We present and discuss start-to-end simulation studies for the shortest wavelength generated in the HGHG cascade of FLASH II.

TUPA22

FLASH II: A Project Update

247

B. Faatz, V. Ayvazyan, N. Baboi, V. Balandin, W. Decking, S. Düsterer, H.-J. Eckoldt, M. Felber, J. Feldhaus, N. Golubeva, K. Honkavaara, M. Körfer, T. Laarmann, A. Leuschner, L. Lilje, T. Limberg, D. Nölle, F. Obier, A. Petrov, E. Plönjes, K. Rehlich, H. Schlarb, B. Schmidt, M. Schmitz, S. Schreiber, H. Schulte-Schrepping, J. Spengler, M. Staack, K.I. Tiedtke, M. Tischer, R. Treusch, M. Vogt, H.C. Weddig
DESY, Hamburg, Germany
J. Bahrdt, R. Follath, K. Holldack, A. Meseck, R. Mitzner
HZB, Berlin, Germany
J. Chen, H.X. Deng, B. Liu
SINAP, Shanghai, People's Republic of China
M. Drescher, A. Hage, V. Miltchev, R. Riedel, J. Rönsch-Schulenburg, J. Roßbach, M. Schulz, A. Willner
Uni HH, Hamburg, Germany
M. Gensch
HZDR, Dresden, Germany
F. Tavella
HIJ, Jena, Germany

FLASH II is an extension of the existing FLASH facility by an undulator line and an experimental Hall of which the construction will start before the end of the year. Aims are to increase beamtime for users and implement HHG seeding for the longer wavelength range from 10 to 40 nm at a reduced repetition rate of 100 kHz. Additional seeding schemes are under discussion as a future option. We will present a progress report of FLASH II.

TUPB04

Status of the FEL User Facility FLASH

267

S. Schreiber, B. Faatz, J. Feldhaus, K. Honkavaara, R. Treusch, M. Vogt
DESY, Hamburg, Germany

The free-electron laser FLASH at DESY, Germany has been upgraded in 2010 and extended its wavelength range down to 4.1 nm. Beside the increased electron beam energy to 1.25 GeV, an other important upgrade is the installation of 3.9 GHz superconducting RF cavities in the injector. They are used to shape the longitudinal electron beam phase space. Now, significantly more FEL radiation energy per pulse of up to several hundreds of microjoules are achieved. Moreover, the system allows to adjust the FEL pulse length, from long pulses of more than 200 fs to short pulses well below 50 fs. The upgraded FLASH facility shows an excellent performance in terms of FEL radiation quality and stability as well as in reliability of operation. The 3rd user period started as scheduled in September 2010.

THPB21

Extraction Arc for FLASH2

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.