FEL2014 - List of Authors (Faatz, B.)

Paper

Title

Page

First Lasing at FLASH2

7

S. Schreiber, B. Faatz
DESY, Hamburg, Germany

FLASH, the free-electron laser user facility at DESY (Hamburg, Germany), has been upgraded with a second undulator beamline FLASH2. The installation of the FLASH2 electron beamline, including twelve variable gap undulators, was finalized early 2014, and beam commissioning of the new beamline started in March 2014. We announce first lasing at FLASH2 achieved at a wavelength of 40 nm on August 20, 2014.

Slides MOA03 [3.896 MB]

MOP006

Coherent Accelerator-based High Field THz Radiation at FLASH II

T. Golz, V. B. Asgekar, B. Faatz, G. Geloni, N. Stojanovic, M. Tischer, P. Vagin, M. Vogt
DESY, Hamburg, Germany
M. Gensch
HZDR, Dresden, Germany
P. Vobly
BINP SB RAS, Novosibirsk, Russia

Funding: BMBF grant no. 05K10CHC + 05K10KEB + 05K12CH4
Linear accelerator based light sources with their tunable broad spectral range (THz to hard X-rays regime) and their ability to generate ultra-short pulses with peak intensities many orders of magnitude higher then synchrotron sources, gave rise to a new field of ultrafast physics. In the THz range, the ability of 4th gen. light sources to generate pulses with e-field strengths up to 1 GV/m opened the door to the field of non-linear THz spectroscopy and THz-controlled material science. The main advantage of accelerator-based THz is its scaleability. As the process is not bound to a particular medium, but occurs in the accelerator vacuum, it bypasses the limitation of table top sources. In addition, it has been demonstrated that coherent THz radiation can be generated along femtosecond X-ray pulses in 4th Generation X-ray Light sources such as FLASH [1,2,3] and LCLS [4]. This opens up the opportunity for naturally synchronized THz pump X-ray probe experiments on a few femtosecond time scale [1,2,4]. Here we present the design for the THz source at FLASH2, which takes new findings [5] and challenges into account that we face during the radiation transport to the experimental hall.

MOP089

Overview of FEL Seeding Activities at FLASH

J. Bödewadt, S. Ackermann, R.W. Aßmann, N. Ekanayake, B. Faatz, G. Feng, I. Hartl, R. Ivanov, T. Laarmann, J.M. Mueller, T. Tanikawa
DESY, Hamburg, Germany
S. Ackermann, A. Azima, M. Drescher, L.L. Lazzarino, C. Lechner, Th. Maltezopoulos, V. Miltchev, T. Plath, J. Roßbach
Uni HH, Hamburg, Germany
K.E. Hacker, S. Khan, R. Molo
DELTA, Dortmund, Germany

The free-electron laser facility FLASH at DESY operates since several years in SASE mode, delivering high-intensity FEL pulses in the extreme ultra violet and soft x-ray wavelength range for users. In order to get more control of the characteristics of the FEL pulses external FEL seeding has proven to be a reliable method to do so. At FLASH, an experimental setup to test several different external seeding methods has been installed since 2010. After successful demonstration of direct seeding at 38 nm, the setup is now being commissioned to operate in HGHG and EEHG mode. Furthermore, other studies on laser induced effects on the electron beam dynamics will be performed. Beside the experimental activities, a design for the seeding option for the FLASH2 beamline is currently under investigation. The goal for that is to develop a concept which is compatible with the operation of FLASH1 and which satisfies the high demands of the future user community. In this contribution, we give an overview of the activities on FEL seeding at FLASH.

WEB05

FLASH: First Soft X-ray FEL Operating Two Undulator Beamlines Simultaneously

635

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

FLASH, the free electron laser user facility at DESY (Hamburg, Germany), has been upgraded with a second undulator beamline FLASH2. After a shutdown to connect FLASH2 to the FLASH linac, FLASH1 is back in user operation since February 2014. Installation of the FLASH2 electron beamline has been completed early 2014, and the first electron beam was transported into the new beamline in March 2014. The commissioning of FLASH2 takes place in 2014 parallel to FLASH1 user operation. This paper reports the status of the FLASH facility, and the first experience of operating two FEL beamlines.

Slides WEB05 [2.481 MB]

THP073

Optics Measurements at FLASH2

902

M. Scholz, B. Faatz, M. Vogt, J. Zemella
DESY, Hamburg, Germany

FLASH2 is a newly build second beam line at FLASH, the soft X-ray FEL at DESY, Hamburg. Unlike the existing beam line FLASH1, it is equipped with variable gap undulators. This beam line is currently being commissioned. Both undulator beam lines of FLASH are driven by a common linear accelerator. Fast kickers and a septum are installed at the end of the linac to distribute the electron bunches of every train between FLASH1 and FLASH2. A specific beam optic in the extraction arc with horizontal beam waists in the bending magnets is mandatory in order to mitigate CSR effects. Here we will show first results of measurements and compare to simulations.

THP076

Measurements of the Timing Stability at the FLASH1 Seeding Experiment

913

C. Lechner, A. Azima, M. Drescher, L.L. Lazzarino, Th. Maltezopoulos, V. Miltchev, T. Plath, J. Rönsch-Schulenburg, J. Roßbach, M. Wieland
Uni HH, Hamburg, Germany
S. Ackermann, J. Bödewadt, H. Dachraoui, N. Ekanayake, B. Faatz, M. Felber, K. Honkavaara, T. Laarmann, J.M. Mueller, H. Schlarb, S. Schreiber, S. Schulz
DESY, Hamburg, Germany
G. Angelova Hamberg
Uppsala University, Uppsala, Sweden
K.E. Hacker, S. Khan, R. Molo
DELTA, Dortmund, Germany
P.M. Salen, P. van der Meulen
FYSIKUM, AlbaNova, Stockholm University, Stockholm, Sweden

Funding: Supported by Federal Ministry of Education and Research of Germany under contract No. 05K10PE1, 05K10PE3, 05K13GU4 and 05K13PE3 and the German Research Foundation programme graduate school 1355.
For seeding of a free-electron laser, the spatial and temporal overlap of the seed laser pulse and the electron bunch in the modulator is critical. To establish the temporal overlap, the time difference between pulses from the seed laser and spontaneous undulator radiation is reduced to a few pico-seconds with a combination of a photomultiplier tube and a streak camera. Finally, for the precise overlap the impact of the seed laser pulses on the electron bunches is observed. In this contribution, we describe the current experimental setup, discuss the techniques applied to establish the temporal overlap and analyze its stability.

Paper	Title	Page
MOA03	First Lasing at FLASH2	7
	S. Schreiber, B. Faatz DESY, Hamburg, Germany
	FLASH, the free-electron laser user facility at DESY (Hamburg, Germany), has been upgraded with a second undulator beamline FLASH2. The installation of the FLASH2 electron beamline, including twelve variable gap undulators, was finalized early 2014, and beam commissioning of the new beamline started in March 2014. We announce first lasing at FLASH2 achieved at a wavelength of 40 nm on August 20, 2014.
	Slides MOA03 [3.896 MB]

MOP006	Coherent Accelerator-based High Field THz Radiation at FLASH II
	T. Golz, V. B. Asgekar, B. Faatz, G. Geloni, N. Stojanovic, M. Tischer, P. Vagin, M. Vogt DESY, Hamburg, Germany M. Gensch HZDR, Dresden, Germany P. Vobly BINP SB RAS, Novosibirsk, Russia
	Funding: BMBF grant no. 05K10CHC + 05K10KEB + 05K12CH4 Linear accelerator based light sources with their tunable broad spectral range (THz to hard X-rays regime) and their ability to generate ultra-short pulses with peak intensities many orders of magnitude higher then synchrotron sources, gave rise to a new field of ultrafast physics. In the THz range, the ability of 4th gen. light sources to generate pulses with e-field strengths up to 1 GV/m opened the door to the field of non-linear THz spectroscopy and THz-controlled material science. The main advantage of accelerator-based THz is its scaleability. As the process is not bound to a particular medium, but occurs in the accelerator vacuum, it bypasses the limitation of table top sources. In addition, it has been demonstrated that coherent THz radiation can be generated along femtosecond X-ray pulses in 4th Generation X-ray Light sources such as FLASH [1,2,3] and LCLS [4]. This opens up the opportunity for naturally synchronized THz pump X-ray probe experiments on a few femtosecond time scale [1,2,4]. Here we present the design for the THz source at FLASH2, which takes new findings [5] and challenges into account that we face during the radiation transport to the experimental hall.

MOP089	Overview of FEL Seeding Activities at FLASH
	J. Bödewadt, S. Ackermann, R.W. Aßmann, N. Ekanayake, B. Faatz, G. Feng, I. Hartl, R. Ivanov, T. Laarmann, J.M. Mueller, T. Tanikawa DESY, Hamburg, Germany S. Ackermann, A. Azima, M. Drescher, L.L. Lazzarino, C. Lechner, Th. Maltezopoulos, V. Miltchev, T. Plath, J. Roßbach Uni HH, Hamburg, Germany K.E. Hacker, S. Khan, R. Molo DELTA, Dortmund, Germany
	The free-electron laser facility FLASH at DESY operates since several years in SASE mode, delivering high-intensity FEL pulses in the extreme ultra violet and soft x-ray wavelength range for users. In order to get more control of the characteristics of the FEL pulses external FEL seeding has proven to be a reliable method to do so. At FLASH, an experimental setup to test several different external seeding methods has been installed since 2010. After successful demonstration of direct seeding at 38 nm, the setup is now being commissioned to operate in HGHG and EEHG mode. Furthermore, other studies on laser induced effects on the electron beam dynamics will be performed. Beside the experimental activities, a design for the seeding option for the FLASH2 beamline is currently under investigation. The goal for that is to develop a concept which is compatible with the operation of FLASH1 and which satisfies the high demands of the future user community. In this contribution, we give an overview of the activities on FEL seeding at FLASH.

WEB05	FLASH: First Soft X-ray FEL Operating Two Undulator Beamlines Simultaneously	635
	K. Honkavaara, B. Faatz, J. Feldhaus, S. Schreiber, R. Treusch, M. Vogt DESY, Hamburg, Germany
	FLASH, the free electron laser user facility at DESY (Hamburg, Germany), has been upgraded with a second undulator beamline FLASH2. After a shutdown to connect FLASH2 to the FLASH linac, FLASH1 is back in user operation since February 2014. Installation of the FLASH2 electron beamline has been completed early 2014, and the first electron beam was transported into the new beamline in March 2014. The commissioning of FLASH2 takes place in 2014 parallel to FLASH1 user operation. This paper reports the status of the FLASH facility, and the first experience of operating two FEL beamlines.
	Slides WEB05 [2.481 MB]

THP073	Optics Measurements at FLASH2	902
	M. Scholz, B. Faatz, M. Vogt, J. Zemella DESY, Hamburg, Germany
	FLASH2 is a newly build second beam line at FLASH, the soft X-ray FEL at DESY, Hamburg. Unlike the existing beam line FLASH1, it is equipped with variable gap undulators. This beam line is currently being commissioned. Both undulator beam lines of FLASH are driven by a common linear accelerator. Fast kickers and a septum are installed at the end of the linac to distribute the electron bunches of every train between FLASH1 and FLASH2. A specific beam optic in the extraction arc with horizontal beam waists in the bending magnets is mandatory in order to mitigate CSR effects. Here we will show first results of measurements and compare to simulations.

THP076	Measurements of the Timing Stability at the FLASH1 Seeding Experiment	913
	C. Lechner, A. Azima, M. Drescher, L.L. Lazzarino, Th. Maltezopoulos, V. Miltchev, T. Plath, J. Rönsch-Schulenburg, J. Roßbach, M. Wieland Uni HH, Hamburg, Germany S. Ackermann, J. Bödewadt, H. Dachraoui, N. Ekanayake, B. Faatz, M. Felber, K. Honkavaara, T. Laarmann, J.M. Mueller, H. Schlarb, S. Schreiber, S. Schulz DESY, Hamburg, Germany G. Angelova Hamberg Uppsala University, Uppsala, Sweden K.E. Hacker, S. Khan, R. Molo DELTA, Dortmund, Germany P.M. Salen, P. van der Meulen FYSIKUM, AlbaNova, Stockholm University, Stockholm, Sweden
	Funding: Supported by Federal Ministry of Education and Research of Germany under contract No. 05K10PE1, 05K10PE3, 05K13GU4 and 05K13PE3 and the German Research Foundation programme graduate school 1355. For seeding of a free-electron laser, the spatial and temporal overlap of the seed laser pulse and the electron bunch in the modulator is critical. To establish the temporal overlap, the time difference between pulses from the seed laser and spontaneous undulator radiation is reduced to a few pico-seconds with a combination of a photomultiplier tube and a streak camera. Finally, for the precise overlap the impact of the seed laser pulses on the electron bunches is observed. In this contribution, we describe the current experimental setup, discuss the techniques applied to establish the temporal overlap and analyze its stability.