IBIC2012 - List of Authors (Weiland, T.)

Paper

Title

Page

RF Front end for High Bandwidth Bunch Arrival Time Monitors in Free-Electron Lasers at DESY

157

A. Penirschke, A. Angelovski, M. Hansli, R. Jakoby
TU Darmstadt, Darmstadt, Germany
M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo
DESY, Hamburg, Germany
A. Kuhl
Uni HH, Hamburg, Germany
S. Schnepp
IFH, Zurich, Switzerland
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors"
The Free-Electron Laser in Hamburg FLASH is equipped with Bunch Arrival-time Monitors (BAMs) that use an electro-optical detection scheme to modulate the intensity of the femtosecond laser pulse train with the pickup signals (*). The achieved resolution of the existing BAMs are less than 10 fs for bunch charges higher than 500 pC. For lower bunch charges the time resolution drops significantly. Increased demands for low bunch charge operation modes of 20 pC and less at FLASH II and the European X-ray Free-Electron Laser XFEL require an upgrade of the existing beam diagnostic equipment. High bandwidth BAMs with newly developed cone-shaped pickups (**) promise sub-10 fs time resolution for both, the high and low bunch charge operation mode. This paper addresses the RF signal path of the high bandwidth BAMs for FLASH II and XFEL. It comprises radiation resistant coaxial cables, combiners and limiters up to a frequency of 40 GHz from the pickup electrodes to the Electro-optical Mach-Zehnder type modulator (EOM). Detailed investigations of the signal path using measurements and simulations with AWR Microwave Office allows for a good prediction of the signal quality and shape at the EOM.
(*) F. Löhl et al., Phys. Rev. Lett. 104,144801 (2010)
(**) A. Angelovski et al. in Proceedings of the International Particle Accelerator Conference (IPAC2011), San Sebastian, Spain, 2011, p.1177

MOPA46

Realization and Measurements of Cone-shaped Pickups for Bunch Arrival-time Monitors for FLASH and XFEL

165

A. Angelovski, M. Hansli, R. Jakoby, A. Penirschke
TU Darmstadt, Darmstadt, Germany
M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo
DESY, Hamburg, Germany
A. Kuhl
Uni HH, Hamburg, Germany
S. Schnepp
IFH, Zurich, Switzerland
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors"
At the Free Electron Laser FLASH at DESY, the installed Bunch Arrival-time Monitors (BAMs) use an electro-optical detection scheme for arrival-time measurements. The achieved time resolution is in the sub-10 fs range for bunch charges higher than 500 pC. The extension of FLASH II and the European X-ray Free Electron Laser Project (XFEL) foresees a low charge operation mode with bunch charge of 20 pC or less. The time resolution of the BAMs significantly drops as the bunch charge reduces (*). By expanding the bandwidth of the pickups one can increase the time resolution at low charges. In this paper, we present the characterization results of the manufactured cone-shaped pickups introduced in (**) with a bandwidth up to 40 GHz. The pickups mounted in a vacuum body exhibit four-fold rotational symmetry with respect to the beam pipe. Due to different beam pipe apertures for FLASH and XFEL, two bodies are manufactured. The rf properties of the mounted pickups in case of open and sealed body as well as the pickups separately are measured and compared to the simulation results obtained by CST STUDIO SUITE®.
(*)M. K. Bock et al. in Proceedings of DIPAC 2011, Hamburg, Germany, 2011, p.365
(**)A. Angelovski et al. in Proceedings of IPAC 2011, San Sebastian, Spain, 2011, p.1177

WECC04

Analysis of the Electro-optical Front End for the New 40 GHz Bunch Arrival Time Monitor System

571

A. Kuhl, J. Rönsch-Schulenburg, J. Roßbach
Uni HH, Hamburg, Germany
A. Angelovski, R. Jakoby, A. Penirschke
TU Darmstadt, Darmstadt, Germany
M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo
DESY, Hamburg, Germany
S. Schnepp
IFH, Zurich, Switzerland
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

The Free electron LASer in Hamburg (FLASH) is currently equipped with four Bunch Arrival time Monitors (BAMs) which achieve a time resolution of less than 10 fs for bunch charges higher than 500 pC (1). In order to achieve single spike FEL pulses at FLASH, electron bunch charges down to 20 pC are of interest. With the current BAMs the required time resolution is not reachable for bunch charges below 500 pC. Therefore new pickups with a bandwidth of up to 40 GHz (2) are designed and manufactured. The signal evaluation takes place with a time-stabilized reference laser pulse train which is modulated with an Electro-Optical intensity Modulator (EOM). The new pickup system also requires a new electro-optical frontend with a 40 GHz EOM. The theoretical limits of the time resolution depending on the RF signal at different bunch charges and on the jitter of the reference laser pulses where analyzed for the new EOM.
(1) M. K. Bock et al. in Proceedings of DIPAC 2011, Hamburg, Germany,2011, p. 365
(2) A. Angelovski, A. Kuhl et al. in Proceedings of IPAC 2011, San Sebastian, Spain, 2011, p. 1177 and p. 1186

Slides WECC04 [12.560 MB]

Paper	Title	Page
MOPA43	RF Front end for High Bandwidth Bunch Arrival Time Monitors in Free-Electron Lasers at DESY	157
	A. Penirschke, A. Angelovski, M. Hansli, R. Jakoby TU Darmstadt, Darmstadt, Germany M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo DESY, Hamburg, Germany A. Kuhl Uni HH, Hamburg, Germany S. Schnepp IFH, Zurich, Switzerland T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors" The Free-Electron Laser in Hamburg FLASH is equipped with Bunch Arrival-time Monitors (BAMs) that use an electro-optical detection scheme to modulate the intensity of the femtosecond laser pulse train with the pickup signals (). The achieved resolution of the existing BAMs are less than 10 fs for bunch charges higher than 500 pC. For lower bunch charges the time resolution drops significantly. Increased demands for low bunch charge operation modes of 20 pC and less at FLASH II and the European X-ray Free-Electron Laser XFEL require an upgrade of the existing beam diagnostic equipment. High bandwidth BAMs with newly developed cone-shaped pickups () promise sub-10 fs time resolution for both, the high and low bunch charge operation mode. This paper addresses the RF signal path of the high bandwidth BAMs for FLASH II and XFEL. It comprises radiation resistant coaxial cables, combiners and limiters up to a frequency of 40 GHz from the pickup electrodes to the Electro-optical Mach-Zehnder type modulator (EOM). Detailed investigations of the signal path using measurements and simulations with AWR Microwave Office allows for a good prediction of the signal quality and shape at the EOM. () F. Löhl et al., Phys. Rev. Lett. 104,144801 (2010) (**) A. Angelovski et al. in Proceedings of the International Particle Accelerator Conference (IPAC2011), San Sebastian, Spain, 2011, p.1177

MOPA46	Realization and Measurements of Cone-shaped Pickups for Bunch Arrival-time Monitors for FLASH and XFEL	165
	A. Angelovski, M. Hansli, R. Jakoby, A. Penirschke TU Darmstadt, Darmstadt, Germany M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo DESY, Hamburg, Germany A. Kuhl Uni HH, Hamburg, Germany S. Schnepp IFH, Zurich, Switzerland T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors" At the Free Electron Laser FLASH at DESY, the installed Bunch Arrival-time Monitors (BAMs) use an electro-optical detection scheme for arrival-time measurements. The achieved time resolution is in the sub-10 fs range for bunch charges higher than 500 pC. The extension of FLASH II and the European X-ray Free Electron Laser Project (XFEL) foresees a low charge operation mode with bunch charge of 20 pC or less. The time resolution of the BAMs significantly drops as the bunch charge reduces (). By expanding the bandwidth of the pickups one can increase the time resolution at low charges. In this paper, we present the characterization results of the manufactured cone-shaped pickups introduced in () with a bandwidth up to 40 GHz. The pickups mounted in a vacuum body exhibit four-fold rotational symmetry with respect to the beam pipe. Due to different beam pipe apertures for FLASH and XFEL, two bodies are manufactured. The rf properties of the mounted pickups in case of open and sealed body as well as the pickups separately are measured and compared to the simulation results obtained by CST STUDIO SUITE®. ()M. K. Bock et al. in Proceedings of DIPAC 2011, Hamburg, Germany, 2011, p.365 (**)A. Angelovski et al. in Proceedings of IPAC 2011, San Sebastian, Spain, 2011, p.1177

WECC04	Analysis of the Electro-optical Front End for the New 40 GHz Bunch Arrival Time Monitor System	571
	A. Kuhl, J. Rönsch-Schulenburg, J. Roßbach Uni HH, Hamburg, Germany A. Angelovski, R. Jakoby, A. Penirschke TU Darmstadt, Darmstadt, Germany M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo DESY, Hamburg, Germany S. Schnepp IFH, Zurich, Switzerland T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	The Free electron LASer in Hamburg (FLASH) is currently equipped with four Bunch Arrival time Monitors (BAMs) which achieve a time resolution of less than 10 fs for bunch charges higher than 500 pC (1). In order to achieve single spike FEL pulses at FLASH, electron bunch charges down to 20 pC are of interest. With the current BAMs the required time resolution is not reachable for bunch charges below 500 pC. Therefore new pickups with a bandwidth of up to 40 GHz (2) are designed and manufactured. The signal evaluation takes place with a time-stabilized reference laser pulse train which is modulated with an Electro-Optical intensity Modulator (EOM). The new pickup system also requires a new electro-optical frontend with a 40 GHz EOM. The theoretical limits of the time resolution depending on the RF signal at different bunch charges and on the jitter of the reference laser pulses where analyzed for the new EOM. (1) M. K. Bock et al. in Proceedings of DIPAC 2011, Hamburg, Germany,2011, p. 365 (2) A. Angelovski, A. Kuhl et al. in Proceedings of IPAC 2011, San Sebastian, Spain, 2011, p. 1177 and p. 1186
	Slides WECC04 [12.560 MB]