FEL2012 - List of Authors (Gross, M.)

Paper	Title	Page
MOPD59	PITZ Status, Recent Measurements and Tests	181
	M. Krasilnikov, H.-J. Grabosch, M. Groß, I.I. Isaev, Ye. Ivanisenko, M. Khojoyan, G. Klemz, G. Kourkafas, M. Mahgoub, D. Malyutin, B. Marchetti, A. Oppelt, M. Otevřel, B. Petrosyan, A. Shapovalov, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany K. Kusoljariyakul FNRF, Chiang Mai, Thailand J. Li USTC/NSRL, Hefei, Anhui, People's Republic of China D. Richter HZB, Berlin, Germany S. Rimjaem Chiang Mai University, Chiang Mai, Thailand I. Will MBI, Berlin, Germany
	The photo injector test facility at DESY, Zeuthen site (PITZ) is dedicated to the development and optimization of a high-brightness electron source for the European XFEL. Recently a significant upgrade has been done at the facility. A new RF system has been installed for the PITZ gun, enabling higher attainable peak power in the cavity which is important for efficient LLRF regulation. First long-term tests for a stable gun operation at high duty cycle have been performed. Two major components for electron beam diagnostics - a transverse deflecting cavity for time resolved electron bunch characterization, and a second high energy dispersive arm for precise longitudinal phase space measurements - have been installed. First results of their commissioning will be reported.

MOPD60	Optimization of the Transverse Projected Emittance of the Electron Beam at PITZ	185
	G. Vashchenko, M. Groß, L. Hakobyan, I.I. Isaev, Ye. Ivanisenko, M. Krasilnikov, M. Mahgoub, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, S. Rimjaem, A. Shapovalov, F. Stephan DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria M. Khojoyan ANSL, Yerevan, Armenia D. Richter HZB, Berlin, Germany
	High brightness electron sources for linac based free-electron lasers operating at short wavelength such as the Free-Electron Laser in Hamburg at DESY, Hamburg Site (FLASH) and the European X-Ray Laser Project XFEL (European XFEL) are characterized and optimized at the Photo Injector Test Facility at DESY, Zeuthen Site (PITZ). One of the most important parameters influencing the FEL process is the normalized transverse projected emittance of the electron beam. The major part of the experimental program at PITZ is devoted to its optimization. Detailed simulations of the present facility setup are performed for a 1 nC bunch charge in order to optimize the transverse projected emittance of the electron beam. Cathode laser pulse length and transverse spot size at the photo cathode, gun and booster accelerating gradients and their launching phases as well as the main solenoid current are optimized. Simulations results together with experimental data are presented.

MOPD61	Laser Pulse Train Management with an Acousto-optic Modulator	189
	M. Groß, H.-J. Grabosch, L. Hakobyan, I.I. Isaev, Ye. Ivanisenko, M. Khojoyan, G. Klemz, G. Kourkafas, M. Krasilnikov, K. Kusoljariyakul, J. Li, M. Mahgoub, D. Malyutin, B. Marchetti, A. Oppelt, M. Otevřel, B. Petrosyan, A. Shapovalov, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany D. Richter HZB, Berlin, Germany H. Schlarb, S. Schreiber DESY, Hamburg, Germany
	Photo injector laser systems for linac based FELs often have the capability of generating pulse trains with an adjustable length. For example, the currently installed laser at the Photo Injector Test Facility at DESY, Zeuthen Site (PITZ) can generate pulse trains containing up to 800 pulses. Repetition frequencies are 10 Hz for the pulse trains and 1 MHz for the pulses within a train, respectively. Mostly due to thermal effects caused by absorption in amplifier and frequency doubling crystals, pulse properties are changing slightly within a pulse train and also shot-to-shot, depending on the pulse train length. To increase stability and repeatability of the laser it is desirable to run it under constant conditions. To achieve this while still being able to freely choose pulse patterns a pulse picker to sort the wanted from the unwanted pulses can be installed at the laser output. A promising candidate for this functionality is an acousto-optic modulator which currently is being tested at PITZ. First experimental results will be presented and discussed towards the possibility of including this device into an FEL photo injector.

WEPD08	Upgrades of the Photoinjector Laser System at FLASH	385
	S. Schreiber, C. Grün, O. Hensler, K. Klose, S. Schulz, T. Schulz, M. Staack DESY, Hamburg, Germany M. Groß, G. Klemz, G. Koss DESY Zeuthen, Zeuthen, Germany I.H. Templin, I. Will, H. Willert MBI, Berlin, Germany
	The photoinjector of FLASH uses an RF gun equipped with caesium telluride photocathodes illuminated by appropriate UV laser pulses as a source of ultra-bright electron beams. The superconducting accelerator of FLASH is able to accelerate a 0.8 ms long train of thousands of electron bunches in a burst mode. This puts special demands on the design of the electron source, especially the laser system. The construction of a second undulator beamline FLASH2 has started. The pulse train will be divided into two parts to serve both beamlines simultaneously. Since experiments with the FLASH soft X-ray beam need flexibility, we plan to use two laser systems each serving one beamline. This makes it possible to deliver two trains with different properties in charge, number of bunches, and bunch spacing in the same RF pulse. This also required an upgrades of the laser beamline design. We report on improvements of the laser beamline and first tests operating two lasers simultaneously at FLASH.

Paper

Title

Page

PITZ Status, Recent Measurements and Tests

181

M. Krasilnikov, H.-J. Grabosch, M. Groß, I.I. Isaev, Ye. Ivanisenko, M. Khojoyan, G. Klemz, G. Kourkafas, M. Mahgoub, D. Malyutin, B. Marchetti, A. Oppelt, M. Otevřel, B. Petrosyan, A. Shapovalov, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
K. Kusoljariyakul
FNRF, Chiang Mai, Thailand
J. Li
USTC/NSRL, Hefei, Anhui, People's Republic of China
D. Richter
HZB, Berlin, Germany
S. Rimjaem
Chiang Mai University, Chiang Mai, Thailand
I. Will
MBI, Berlin, Germany

The photo injector test facility at DESY, Zeuthen site (PITZ) is dedicated to the development and optimization of a high-brightness electron source for the European XFEL. Recently a significant upgrade has been done at the facility. A new RF system has been installed for the PITZ gun, enabling higher attainable peak power in the cavity which is important for efficient LLRF regulation. First long-term tests for a stable gun operation at high duty cycle have been performed. Two major components for electron beam diagnostics - a transverse deflecting cavity for time resolved electron bunch characterization, and a second high energy dispersive arm for precise longitudinal phase space measurements - have been installed. First results of their commissioning will be reported.

MOPD60

Optimization of the Transverse Projected Emittance of the Electron Beam at PITZ

185

G. Vashchenko, M. Groß, L. Hakobyan, I.I. Isaev, Ye. Ivanisenko, M. Krasilnikov, M. Mahgoub, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, S. Rimjaem, A. Shapovalov, F. Stephan
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
M. Khojoyan
ANSL, Yerevan, Armenia
D. Richter
HZB, Berlin, Germany

High brightness electron sources for linac based free-electron lasers operating at short wavelength such as the Free-Electron Laser in Hamburg at DESY, Hamburg Site (FLASH) and the European X-Ray Laser Project XFEL (European XFEL) are characterized and optimized at the Photo Injector Test Facility at DESY, Zeuthen Site (PITZ). One of the most important parameters influencing the FEL process is the normalized transverse projected emittance of the electron beam. The major part of the experimental program at PITZ is devoted to its optimization. Detailed simulations of the present facility setup are performed for a 1 nC bunch charge in order to optimize the transverse projected emittance of the electron beam. Cathode laser pulse length and transverse spot size at the photo cathode, gun and booster accelerating gradients and their launching phases as well as the main solenoid current are optimized. Simulations results together with experimental data are presented.

MOPD61

Laser Pulse Train Management with an Acousto-optic Modulator

189

M. Groß, H.-J. Grabosch, L. Hakobyan, I.I. Isaev, Ye. Ivanisenko, M. Khojoyan, G. Klemz, G. Kourkafas, M. Krasilnikov, K. Kusoljariyakul, J. Li, M. Mahgoub, D. Malyutin, B. Marchetti, A. Oppelt, M. Otevřel, B. Petrosyan, A. Shapovalov, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
D. Richter
HZB, Berlin, Germany
H. Schlarb, S. Schreiber
DESY, Hamburg, Germany

Photo injector laser systems for linac based FELs often have the capability of generating pulse trains with an adjustable length. For example, the currently installed laser at the Photo Injector Test Facility at DESY, Zeuthen Site (PITZ) can generate pulse trains containing up to 800 pulses. Repetition frequencies are 10 Hz for the pulse trains and 1 MHz for the pulses within a train, respectively. Mostly due to thermal effects caused by absorption in amplifier and frequency doubling crystals, pulse properties are changing slightly within a pulse train and also shot-to-shot, depending on the pulse train length. To increase stability and repeatability of the laser it is desirable to run it under constant conditions. To achieve this while still being able to freely choose pulse patterns a pulse picker to sort the wanted from the unwanted pulses can be installed at the laser output. A promising candidate for this functionality is an acousto-optic modulator which currently is being tested at PITZ. First experimental results will be presented and discussed towards the possibility of including this device into an FEL photo injector.

WEPD08

Upgrades of the Photoinjector Laser System at FLASH

385

S. Schreiber, C. Grün, O. Hensler, K. Klose, S. Schulz, T. Schulz, M. Staack
DESY, Hamburg, Germany
M. Groß, G. Klemz, G. Koss
DESY Zeuthen, Zeuthen, Germany
I.H. Templin, I. Will, H. Willert
MBI, Berlin, Germany

The photoinjector of FLASH uses an RF gun equipped with caesium telluride photocathodes illuminated by appropriate UV laser pulses as a source of ultra-bright electron beams. The superconducting accelerator of FLASH is able to accelerate a 0.8 ms long train of thousands of electron bunches in a burst mode. This puts special demands on the design of the electron source, especially the laser system. The construction of a second undulator beamline FLASH2 has started. The pulse train will be divided into two parts to serve both beamlines simultaneously. Since experiments with the FLASH soft X-ray beam need flexibility, we plan to use two laser systems each serving one beamline. This makes it possible to deliver two trains with different properties in charge, number of bunches, and bunch spacing in the same RF pulse. This also required an upgrades of the laser beamline design. We report on improvements of the laser beamline and first tests operating two lasers simultaneously at FLASH.