IPAC2012 - List of Authors (Felber, M.)

Paper	Title	Page
MOPPR017	Preliminary Measurement Results of the Upgraded Energy BPM at FLASH	813
	U. Mavrič, M. Felber, C. Gerth, H. Schlarb DESY, Hamburg, Germany W. Jałmużna, A. Piotrowski TUL-DMCS, Łódź, Poland
	The energy beam position monitor in the dispersive section of the two bunch compressors is a valuable instrument for regular operation of FLASH. Recently, an upgrade of the existing instrument to a uTCA form factor has been started. The basic principle of the time-of-flight measurement will remain the same, however the detection of the phases and amplitudes of two pulses has been moved to the programmable gate array. Other changes include different RF frequencies of detection, optimization of the front-end section and integration into the control system. A preliminary version of the system has been tested at FLASH and the results are presented in the paper.

WEPPD048	Laser Synchronization at REGAE using Phase Detection at an Intermediate Frequency	2624
	M. Felber, M. Hoffmann, U. Mavrič, H. Schlarb, S. Schulz DESY, Hamburg, Germany W. Jałmużna TUL-DMCS, Łódź, Poland
	A new linear accelerator is being set up for electron diffraction experiments at DESY. This machine, called REGAE (Relativistic Electron Gun for Atomic Exploration) is composed of a photo-cathode gun and a buncher cavity. It uses a single laser system for both, the generation of the electron bunches and for pump-probe experiments. The required timing jitter between the electron bunches and the laser pulses at the experiment is in the order of 10 fs rms. The conventional method for laser synchronization using RF technique to measure phase-jitter in the baseband is susceptible to distortions caused by ground-loops and electro-magnetic interference. At REGAE a new scheme for an RF-based laser synchronization is deployed. It uses a down-converter which mixes a higher harmonic of the laser repetition rate down to an intermediate frequency (IF). The IF is digitized and its phase calculated. This information is used for the feedback controller keeping the laser and the RF synchronized.

WEPPD049	Characterization of the Engineered Photodiode-based Fiber Link Stabilization Scheme for Optical Synchronization Systems	2627
	T. Lamb, M.K. Bock, M. Felber, F. Ludwig, H. Schlarb, S. Schulz DESY, Hamburg, Germany S. Jabłoński Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
	Pulsed optical synchronization systems are used in modern FELs like FLASH and will be used in the upcoming European XFEL. Their purpose is to distribute synchronization signals with femtosecond stability throughout the machine. Optical fibers are used to transport the pulses carrying the timing information to their end-stations. These fibers have to be continuously delay stabilized in order to achieve the desired precision. In this paper, a photodiode-based detector to measure the drifts of the fiber delay and allows their active correction is presented. Promising results from a first prototype setup of a photodiode-stabilized optical fiber link were the starting point for an engineering of this concept. An enclosure with free-space optics, fiber optics and integrated electronics for the detector, operating at 9.75 GHz, was designed. This unit includes all required parts to stabilize four fiber links. It allows to investigate the temperature sensitivity of the detector. Furthermore, results from drift measurements carried out with a two channel engineered detector are presented in this paper.

Paper

Title

Page

Preliminary Measurement Results of the Upgraded Energy BPM at FLASH

813

U. Mavrič, M. Felber, C. Gerth, H. Schlarb
DESY, Hamburg, Germany
W. Jałmużna, A. Piotrowski
TUL-DMCS, Łódź, Poland

The energy beam position monitor in the dispersive section of the two bunch compressors is a valuable instrument for regular operation of FLASH. Recently, an upgrade of the existing instrument to a uTCA form factor has been started. The basic principle of the time-of-flight measurement will remain the same, however the detection of the phases and amplitudes of two pulses has been moved to the programmable gate array. Other changes include different RF frequencies of detection, optimization of the front-end section and integration into the control system. A preliminary version of the system has been tested at FLASH and the results are presented in the paper.

WEPPD048

Laser Synchronization at REGAE using Phase Detection at an Intermediate Frequency

2624

M. Felber, M. Hoffmann, U. Mavrič, H. Schlarb, S. Schulz
DESY, Hamburg, Germany
W. Jałmużna
TUL-DMCS, Łódź, Poland

A new linear accelerator is being set up for electron diffraction experiments at DESY. This machine, called REGAE (Relativistic Electron Gun for Atomic Exploration) is composed of a photo-cathode gun and a buncher cavity. It uses a single laser system for both, the generation of the electron bunches and for pump-probe experiments. The required timing jitter between the electron bunches and the laser pulses at the experiment is in the order of 10 fs rms. The conventional method for laser synchronization using RF technique to measure phase-jitter in the baseband is susceptible to distortions caused by ground-loops and electro-magnetic interference. At REGAE a new scheme for an RF-based laser synchronization is deployed. It uses a down-converter which mixes a higher harmonic of the laser repetition rate down to an intermediate frequency (IF). The IF is digitized and its phase calculated. This information is used for the feedback controller keeping the laser and the RF synchronized.

WEPPD049

Characterization of the Engineered Photodiode-based Fiber Link Stabilization Scheme for Optical Synchronization Systems

2627

T. Lamb, M.K. Bock, M. Felber, F. Ludwig, H. Schlarb, S. Schulz
DESY, Hamburg, Germany
S. Jabłoński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

Pulsed optical synchronization systems are used in modern FELs like FLASH and will be used in the upcoming European XFEL. Their purpose is to distribute synchronization signals with femtosecond stability throughout the machine. Optical fibers are used to transport the pulses carrying the timing information to their end-stations. These fibers have to be continuously delay stabilized in order to achieve the desired precision. In this paper, a photodiode-based detector to measure the drifts of the fiber delay and allows their active correction is presented. Promising results from a first prototype setup of a photodiode-stabilized optical fiber link were the starting point for an engineering of this concept. An enclosure with free-space optics, fiber optics and integrated electronics for the detector, operating at 9.75 GHz, was designed. This unit includes all required parts to stabilize four fiber links. It allows to investigate the temperature sensitivity of the detector. Furthermore, results from drift measurements carried out with a two channel engineered detector are presented in this paper.