IPAC2012 - List of Authors (Schreiber, S.)

Paper	Title	Page
MOPPP029	Photocathodes at FLASH	625
	S. Lederer, H. Hansen, H.-H. Sahling, S. Schreiber DESY, Hamburg, Germany P. Michelato, L. Monaco, D. Sertore INFN/LASA, Segrate (MI), Italy
	For several years, cesium telluride photocathodes have been successfully used in the photoinjector of the Free-Electron-Laser FLASH at DESY, Germany. They show a high quantum efficiency and long lifetime and produce routinely thousands of bunches per second with a single bunch charge mostly in the range of 0.3 to 1 nC. Recent studies on lifetime, quantum efficiency, dark current, and operating experience is reported. At DESY, a new preparation system has been set-up. First cathodes have been produced and tested.

TUPPP052	Status of FLASH	1715
	K. Honkavaara, B. Faatz, J. Feldhaus, S. Schreiber, R. Treusch, M. Vogt DESY, Hamburg, Germany
	FLASH at DESY (Hamburg, Germany) is a free-electron laser user facility driven by a superconducting 1.25 GeV linac based on TESLA technology. During the 3rd user period from September 2010 to September 2011, totally 3740 hours of FEL radiation has been delivered to FEL experiments at more than 30 different wavelengths between 4.7 nm and 45 nm. In addition, beam time has been dedicated to general accelerator physics studies and developments related to the future projects like the European XFEL and the International Linear Collider. After a 3.5 months shutdown in autumn 2011 due to civil construction for a second undulator beamline - FLASH2 - and a following commissioning and study period, 2012 is mainly dedicated to FEL user experiments. This paper summarizes the operation status of the FLASH facility and gives also a short review of the accelerator studies carried out in 2011 and early 2012. The mid-term plans including FLASH2 are presented as well.

TUPPP053	Investigations on the Optimum Accelerator Parameters for the Ultra-Short Bunch Operation of the Free-Electron Laser in Hamburg (FLASH)	1718
	M. Rehders, J. Rönsch-Schulenburg, J. Roßbach Uni HH, Hamburg, Germany T. Limberg, H. Schlarb, S. Schreiber DESY, Hamburg, Germany
	Funding: The project is supported by the Federal Ministry of Education and Research of Germany (BMBF) under contract No. 05K10GU2 and FSP301. In order to produce the shortest possible radiation pulses using Free Electron Lasers like FLASH, various possibilities have been proposed during the last decade. Probably the most robust method is the generation of electron bunches that in the most extreme case are as short as a single longitudinal optical mode of the SASE (Self-Amplified Spontaneous Emission) radiation. For FLASH this means that the bunch length has to be a few fs only. As a consequence, very low bunch charges (in the order of 20 pC) have to be used. To achieve these extremely short bunch lengths, a new photo-injector laser has been installed, which allows for the generation of shorter electron bunches right at the cathode. Simulations of the electron bunches and their six-dimensional phase-space distribution have been performed to investigate the optimum accelerator parameters during injection and to determine how to realize them. First results are discussed in this contribution.

Paper

Title

Page

Photocathodes at FLASH

625

S. Lederer, H. Hansen, H.-H. Sahling, S. Schreiber
DESY, Hamburg, Germany
P. Michelato, L. Monaco, D. Sertore
INFN/LASA, Segrate (MI), Italy

For several years, cesium telluride photocathodes have been successfully used in the photoinjector of the Free-Electron-Laser FLASH at DESY, Germany. They show a high quantum efficiency and long lifetime and produce routinely thousands of bunches per second with a single bunch charge mostly in the range of 0.3 to 1 nC. Recent studies on lifetime, quantum efficiency, dark current, and operating experience is reported. At DESY, a new preparation system has been set-up. First cathodes have been produced and tested.

TUPPP052

Status of FLASH

1715

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

FLASH at DESY (Hamburg, Germany) is a free-electron laser user facility driven by a superconducting 1.25 GeV linac based on TESLA technology. During the 3rd user period from September 2010 to September 2011, totally 3740 hours of FEL radiation has been delivered to FEL experiments at more than 30 different wavelengths between 4.7 nm and 45 nm. In addition, beam time has been dedicated to general accelerator physics studies and developments related to the future projects like the European XFEL and the International Linear Collider. After a 3.5 months shutdown in autumn 2011 due to civil construction for a second undulator beamline - FLASH2 - and a following commissioning and study period, 2012 is mainly dedicated to FEL user experiments. This paper summarizes the operation status of the FLASH facility and gives also a short review of the accelerator studies carried out in 2011 and early 2012. The mid-term plans including FLASH2 are presented as well.

TUPPP053

Investigations on the Optimum Accelerator Parameters for the Ultra-Short Bunch Operation of the Free-Electron Laser in Hamburg (FLASH)

1718

M. Rehders, J. Rönsch-Schulenburg, J. Roßbach
Uni HH, Hamburg, Germany
T. Limberg, H. Schlarb, S. Schreiber
DESY, Hamburg, Germany

Funding: The project is supported by the Federal Ministry of Education and Research of Germany (BMBF) under contract No. 05K10GU2 and FSP301.
In order to produce the shortest possible radiation pulses using Free Electron Lasers like FLASH, various possibilities have been proposed during the last decade. Probably the most robust method is the generation of electron bunches that in the most extreme case are as short as a single longitudinal optical mode of the SASE (Self-Amplified Spontaneous Emission) radiation. For FLASH this means that the bunch length has to be a few fs only. As a consequence, very low bunch charges (in the order of 20 pC) have to be used. To achieve these extremely short bunch lengths, a new photo-injector laser has been installed, which allows for the generation of shorter electron bunches right at the cathode. Simulations of the electron bunches and their six-dimensional phase-space distribution have been performed to investigate the optimum accelerator parameters during injection and to determine how to realize them. First results are discussed in this contribution.