IBIC2013 - List of Keywords (XFEL)

Paper	Title	Other Keywords	Page
MOPC25	About BPMS to be Used for PAL-XFEL	BPM, pick-up, electron, beam-position	112
	H. J. Choi, H.-S. Kang, C. Kim, S.H. Kim, S.J. Lee, S.J. Park, H. Yang PAL, Pohang, Kyungbuk, Republic of Korea
	Pohang Accelerator Laboratory (PAL) has been building the X-Ray Free Electron Laser (XFEL), a fourth-generation accelerator, and the construction will be complete in 2015. To successfully construct the XFEL, PAL built an injection test facility (ITF) in 2012, and the facility is in operation. The ITF examines the efficiency of various diagnostic units through extended tests. A BPM is a diagnostic unit that measures the position of an electron bunch. There are various kinds of BPM, and they have different merits and demerits. A user can select any kind of BPM that is appropriate for their purpose, and install it after going through various design and production processes. In order to measure the position of an electron bunch, a cavity BPM is installed at an undulator of PAL-XFEL and a stripline BPM is installed at an accelerator. The efficiency of the stripline BPM was tested at the ITF. The X-band cavity BPM was produced and is being tested at the ITF. This paper aims to introduce the specification and properties of the cavity BPM and stripline BPM to be installed at PAL-XFEL, and explain the physical concept and the way of measuring necessary for designing a stripline pickup.

MOPC32	Development Status of Optical Synchronization for the European XFEL	laser, DESY, coupling, shielding	135
	C. Sydlo, M.K. Czwalinna, M. Felber, C. Gerth, T. Lamb, H. Schlarb, S. Schulz, F. Zummack DESY, Hamburg, Germany S. Jabłoński Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
	Precise timing synchronization on the femtosecond timescale is crucial for time resolved experiments at modern free-electron lasers (FELs) like FLASH and the upcoming European XFEL. The required precision can only be achieved by a laser-based synchronization system. The pulsed laser-based scheme at FLASH, based on the distribution of femtosecond laser pulses over actively stabilized optical fibers, has evolved over the years from a prototype setup to a mature and reliable system. At the same time, the present implementation serves as prototype for the synchronization infrastructure at the European XFEL. Due to a factor of ten increase of the length of the accelerator and an increased number of timing-critical subsystems, new challenges arise. This paper reports on the current development progress of the XFEL optical synchronization, discusses major complications and their solutions.

TUPC25	Design of the SwissFEL BPM System	BPM, pick-up, undulator, linac	427
	B. Keil, R. Baldinger, R. Ditter, W. Koprek, R. Kramert, F. Marcellini, G. Marinkovic, M. Roggli, M. Rohrer, M. Stadler, D.M. Treyer PSI, Villigen PSI, Switzerland
	SwissFEL is a Free Electron Laser (FEL) facility being constructed at PSI, based on a 5.8GeV normally conducting main linac. A photocathode gun will generate two bunches with 28ns spacing at 100Hz repetition rate, with a nominal charge range of 10-200pC. A fast beam distribution kicker will allow to distribute one bunch to a soft X-ray undulator line and the other bunch to a 0.1nm hard X-ray undulator line. The SwissFEL electron beam position monitor (BPM) system will employ three different types of dual-resonator cavity BPMs, since the accelerator has three different beam pipe apertures. In the injector and main linac (38mm and 16mm aperture), 3.3GHz cavity BPMs will be used, where a low Q of ~40 was chosen to minimize crosstalk of the two bunches. In the undulators that just have single bunches and 8mm BPM aperture, a higher Q will be chosen. This paper reports on the development status of the SwissFEL BPM system. Synergies as well as differences to the E-XFEL BPM system* will also be highlighted. * F. Marcellini et al., "Design of Cavity BPM Pickups For SwissFEL", Proc. IBIC'12, Tsukuba, Japan, 2012. ** B. Keil et al., "The European XFEL BPM System", Proc. IPAC'10, Kyoto, Japan, 2010.
	Poster TUPC25 [1.074 MB]

TUPC29	Grounded Coplanar Waveguide Transmission Lines as Pickups for Beam Position Monitoring in Particle Accelerators	pick-up, simulation, beam-position, coupling	438
	A. Penirschke, A. Angelovski, R. Jakoby TU Darmstadt, Darmstadt, Germany C. Gerth, U. Mavrič, D. Nölle, C. Sydlo, S. Vilcins DESY, Hamburg, Germany
	Funding: The work was supported by the MSK group at DESY Hamburg. The authors would like to thank the CST AG for providing the CST Software Package. Energy beam position monitors (EBPM) based on grounded co-planar waveguide (GCPW) transmission lines have been designed for installation in the dispersive sections of the bunch compressor chicanes at the European XFEL. In combination with beam position monitors at the entrance and exit of the bunch compressor chicanes, measurements of the beam energy with single bunch resolution are feasible. The EBPM consists of transversely mounted stripline pickups in a rectangular beam pipe section. The signal detection for the measurement of the phases of the pulses at each end of the pickups is based on the standard down-conversion and phase detection scheme used for the low-level RF-system. A measurement resolution within the lower micrometer range can be achieved for input signal reflections at the pickup of less than -25 dB at 3 GHz. In this paper, simulation results of a novel pickup geometry utilized with GCPW pickup structures and optimized transitions to perpendicular mounted coaxial connectors are presented. The simulation results exhibit small reflection coefficients with reflected signal components having less than 2% of the peak voltage signal.

TUPC31	New Design of High Order Modes Electronics in MTCA.4 Standard for FLASH and the European XFEL	DESY, beam-position, monitoring, alignment	443
	S. Bou Habib, A. Abramowicz Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland N. Baboi, H. Schlarb DESY, Hamburg, Germany
	At free-electron linear accelerators, various High Order Modes (HOM) - both monopole and dipole - are excited. Extensive studies at DESY have shown that monitoring and analysis of some of these modes can be used for different applications including Beam Position Monitors (BPMs) and the reduction of wake-fields, the measurement of the beam phase with-respect-to RF signal in cavities, and the measurement of cavity alignment in the 1.3 GHz cryo-modules. Three frequencies were chosen for further experiments: the 1.3 GHz base frequency from the klystron, the 1.7 GHz dipole mode and the 2.4 GHz monopole mode. In order to realize the monitoring and analysis requirements, very high resolution measurements in amplitude, phase and shape (time resolution) are required for all three frequencies simultaneously. In this paper, we present the new HOM electronics prototype including a microstrip and stripline RF tri-passband filter design and measurements and the specialized MTCA.4 Rear Transition Module for HOM measurements with an ultra-fast high-resolution AMC digitizer.
	Poster TUPC31 [1.226 MB]

TUPC33	Femtosecond Stable Laser-to-RF Phase Detection for Optical Synchronization Systems	laser, controls, polarization, monitoring	447
	T. Lamb, M.K. Czwalinna, M. Felber, C. Gerth, H. Schlarb, S. Schulz, C. Sydlo, M. Titberidze, F. Zummack DESY, Hamburg, Germany E. Janas Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland J. Szewiński NCBJ, Świerk/Otwock, Poland
	Optical reference distributions have become an indispensable asset for femtosecond precision synchronization of free-electron lasers. At FLASH and for the future European XFEL, laser pulses are distributed over large distances in round-trip time stabilized fibers to all critical facility sub-systems. Novel Laser-to-RF phase detectors will be used to provide ultra phase stable and long-term drift free microwave signals for the accelerator RF controls. In this paper, we present the recent progress on the design of a fully integrated and engineered version of the L2RF phase detector, together with first experimental results demonstrating so-far unrivaled performance.
	Poster TUPC33 [18.910 MB]

TUPC34	Precision Synchronization of Optical Lasers Based on MTCA.4 Electronics	laser, feedback, DESY, monitoring	451
	U. Mavrič, L. Butkowski, H.T. Duhme, M. Felber, M. Fenner, C. Gerth, P. Peier, H. Schlarb, B. Steffen DESY, Hamburg, Germany T. Kozak, P. Predki TUL-DMCS, Łódź, Poland
	Optical laser have become an integral part of free-electron laser facilities for the purposes of electron bunch generation, external seeding, diagnostics and pump-probe experiments. The ultra-short electron bunches demand a high timing stability and precision synchronization of the optical lasers. In this paper, we present the proof-of-principle for a laser locking application implemented on a MTCA.4 platform. The system design relies on existing MTCA.4 compliant off-the-shelf modules that are available on the market or have been developed for other applications within the particle accelerator community. Besides performance and cost, we also tried to minimize the number of out-of-crate components. Preliminary measurements of laser locking at the FLASH and REGAE particle accelerators are presented, and an outlook for further system development in the area of laser-to-RF synchronization is given.

TUPC35	Upgrade of the Read-out Electronics for the Energy Beam Position Monitors at FLASH and European XFEL	pick-up, beam-position, DESY, SNR	454
	U. Mavrič, C. Gerth, H. Schlarb DESY, Hamburg, Germany A. Piotrowski TUL-DMCS, Łódź, Poland
	The dispersive sections of magnetic bunch compressor chicanes at free-electron lasers are excellent candidates for beam energy measurements. In the rectangular beamline sections of the bunch compressors at FLASH, energy beam position monitors (EBPM) with transversely mounted stripline pickups are installed. In this paper, we present the upgrade of the read-out electronics for signal detection of the EBPM installed at FLASH. The system is based on the MTCA.4 standard and reuses already available MTCA.4 compliant modules. This is also true for gateware and software development which fits into standard MTCA.4 framework development. The performance of the instrument was studied at FLASH during user operation and the results are presented.

WEPC21	Design and Beam Test Results of Button BPMs for the European XFEL	pick-up, BPM, controls, DESY	723
	D.M. Treyer, R. Baldinger, R. Ditter, B. Keil, W. Koprek, G. Marinkovic, M. Roggli PSI, Villigen PSI, Switzerland D. Lipka, D. Nölle, S. Vilcins DESY, Hamburg, Germany
	Funding: Swiss State Secretariat for Education, Research and Innovation The European X-ray Free Electron Laser (E-XFEL) will use a total ~300 button BPMs along the whole accelerator, as well as 160 cavity BPMs. The pickups for the button BPMs have been designed by DESY, whereas the electronics has been developed by PSI. This paper gives an overview of the button BPM system, with focus on the RF front end electronics, signal processing, and overall system performance. Measurement results achieved with prototypes installed at FLASH/DESY and at the SwissFEL Injector Test Facility (SITF) are presented. The position noise obtained with button pickups in a 40.5 mm aperture beam pipe is as low as ~11 um at 20 pC bunch charge.
	Poster WEPC21 [1.595 MB]

WEPC31	New Design of the 40 GHz Bunch Arrival Time Monitor Using MTCA.4 Electronics at FLASH and for the European XFEL	laser, pick-up, DESY, diagnostics	749
	M.K. Czwalinna, C. Gerth, H. Schlarb DESY, Hamburg, Germany S. Bou Habib Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland S. Korolczuk, J. Szewiński NCBJ, Świerk/Otwock, Poland A. Kuhl Uni HH, Hamburg, Germany
	At free-electron lasers, today's pump-probe experiments and seeding schemes make high demands on the electron bunch timing stability with an arrival time jitter reduction down to the femtosecond level. At FLASH and the upcoming European XFEL, the bunch train structures with their high bunch repetition rates allow for an accurate intra-train stabilisation. To realise longitudinal beam-based feedbacks a reliable and precise arrival time detection over a broad range of bunch charges, which can even change from 1 nC down to 20 pC within a bunch train, is essential. Benefitting from the experience at FLASH, the current bunch arrival time monitors (BAMs), based on detection of RF signals from broad-band pick-ups by use of electro-optic modulators, are further developed to cope with the increased requirements. In this paper, we present the new BAM prototype, including an adapted electro-optical front-end and the latest development of the read-out electronics based on the MTCA.4 platform.

WEPC38	Current Status of Development of Optical Synchronization System for PAL XFEL	laser, FEL, feedback, LCLS	772
	C.-K. Min, I. Eom, H.-S. Kang, B.R. Park, S.J. Park PAL, Pohang, Kyungbuk, Republic of Korea K. Jung, J. Kim, J. Lim KAIST, Daejeon, Republic of Korea
	Optical synchronization system has been developed for higher quality PAL XFEL with low timing jitter since 2011. In last two years, laboratory test was successfully performed, and test in our accelerator environment is ongoing. In laboratory, we tested the synchronization of RF master oscillator and optical master oscillator, the stabilization of 610 m optical fiber link, and the remote optical-to-RF conversion. We report recent our development results and summarize on-going optical timing project.
	Poster WEPC38 [3.366 MB]

WEPC45	Beam Loss Monitoring at the European Spallation Source	beam-losses, ESS, LHC, simulation	795
	L. Tchelidze, H. Hassanzadegan, A. Jansson, M. Jarosz ESS, Lund, Sweden
	At the European Spallation Source proton linear accelerator will generate 5 MW protons to be delivered to a target. This high power accelerator will require significant amount of beam instrumentation, among which the beam loss monitoring system is one of the most important for operation. An LHC type ionization chamber will be used with ~54 uC/Gy sensitivity. At most 1.5 mGy/sec radiation levels are expected close to the beam pipe during normal operation, resulting in up to 80 nA current signal in detectors. Loss monitor electronics is designed to be able to measure currents as little as 1% of the expected current up to as much as 1% of the total beam loss, thus ~800 pA – few mA. In order to study beam loss pattern along the accelerator a coherent model of the whole machine is created for the purposes of Monte Carlo particle transport simulations. Data obtained using the model will be stored in a database together with the initial beam loss conditions. The contents of the database will then be processed using custom neural network algorithms to optimize number and position of the loss monitors and to provide reference on the beam loss localization during operation of the machine.
	Poster WEPC45 [1.784 MB]

WEPF03	Scintillating Screen Monitors for Transverse Electron Beam Profile Diagnostics at the European XFEL	electron, OTR, transverse, DESY	807
	Ch. Wiebers, M. Holz, G. Kube, D. Nölle, G. Priebe, H.-Ch. Schröder DESY, Hamburg, Germany
	Transverse beam profile diagnostics in modern electron linear accelerators like FELs or injector LINACs are mainly based on optical transition radiation (OTR) as standard technique which is observed in backward direction when a charged particle beam crosses the boundary between two media with different dielectric properties. The experience from modern LINAC based 4th generation light sources shows that OTR diagnostics might fail because of coherence effects in the OTR emission process. As a consequence, for the European XFEL which is currently under construction in Hamburg, transverse beam profile measurements are based on scintillating screen monitors. The LYSO:Ce screens are oriented such that coherent OTR generated at the screen boundaries will be geometrically suppressed. An additional advantage is that the imaging optics operate in Scheimpflug condition thus adjusting the plane of sharp focus with respect to the CCD chip and significantly increasing the apparent depth of field. This report gives an overview of the measuring principle and the monitor setup together with results of laboratory test measurements and a first prototype test at FLASH (DESY, Hamburg).

WEPF25	Resonator for Charge Measurement at REGAE	DESY, controls, PITZ, LEFT	872
	D. Lipka, J. Lund-Nielsen, M. Seebach DESY, Hamburg, Germany
	A resonator has been developed for the diagnostics of dark current and charge measurements at the European XFEL, FLASH and PITZ. The first induced monopole mode TM01 at 1.3 GHz from charged bunches is used to detect the dark current and charge with high resolution at these accelerators. At REGAE this resonator with electronics is installed to detect the bunch charge because charges below pC are used and this device can resolve it non-destructively. The same electronics as for the dark current and charge measurement is used and the resolution is measured to be 2.3 fC for 200 fC.
	Poster WEPF25 [0.822 MB]

Paper

Title

Other Keywords

Page

MOPC25

About BPMS to be Used for PAL-XFEL

BPM, pick-up, electron, beam-position

112

H. J. Choi, H.-S. Kang, C. Kim, S.H. Kim, S.J. Lee, S.J. Park, H. Yang
PAL, Pohang, Kyungbuk, Republic of Korea

Pohang Accelerator Laboratory (PAL) has been building the X-Ray Free Electron Laser (XFEL), a fourth-generation accelerator, and the construction will be complete in 2015. To successfully construct the XFEL, PAL built an injection test facility (ITF) in 2012, and the facility is in operation. The ITF examines the efficiency of various diagnostic units through extended tests. A BPM is a diagnostic unit that measures the position of an electron bunch. There are various kinds of BPM, and they have different merits and demerits. A user can select any kind of BPM that is appropriate for their purpose, and install it after going through various design and production processes. In order to measure the position of an electron bunch, a cavity BPM is installed at an undulator of PAL-XFEL and a stripline BPM is installed at an accelerator. The efficiency of the stripline BPM was tested at the ITF. The X-band cavity BPM was produced and is being tested at the ITF. This paper aims to introduce the specification and properties of the cavity BPM and stripline BPM to be installed at PAL-XFEL, and explain the physical concept and the way of measuring necessary for designing a stripline pickup.

MOPC32

Development Status of Optical Synchronization for the European XFEL

laser, DESY, coupling, shielding

135

C. Sydlo, M.K. Czwalinna, M. Felber, C. Gerth, T. Lamb, H. Schlarb, S. Schulz, F. Zummack
DESY, Hamburg, Germany
S. Jabłoński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

Precise timing synchronization on the femtosecond timescale is crucial for time resolved experiments at modern free-electron lasers (FELs) like FLASH and the upcoming European XFEL. The required precision can only be achieved by a laser-based synchronization system. The pulsed laser-based scheme at FLASH, based on the distribution of femtosecond laser pulses over actively stabilized optical fibers, has evolved over the years from a prototype setup to a mature and reliable system. At the same time, the present implementation serves as prototype for the synchronization infrastructure at the European XFEL. Due to a factor of ten increase of the length of the accelerator and an increased number of timing-critical subsystems, new challenges arise. This paper reports on the current development progress of the XFEL optical synchronization, discusses major complications and their solutions.

TUPC25

Design of the SwissFEL BPM System

BPM, pick-up, undulator, linac

427

B. Keil, R. Baldinger, R. Ditter, W. Koprek, R. Kramert, F. Marcellini, G. Marinkovic, M. Roggli, M. Rohrer, M. Stadler, D.M. Treyer
PSI, Villigen PSI, Switzerland

SwissFEL is a Free Electron Laser (FEL) facility being constructed at PSI, based on a 5.8GeV normally conducting main linac. A photocathode gun will generate two bunches with 28ns spacing at 100Hz repetition rate, with a nominal charge range of 10-200pC. A fast beam distribution kicker will allow to distribute one bunch to a soft X-ray undulator line and the other bunch to a 0.1nm hard X-ray undulator line. The SwissFEL electron beam position monitor (BPM) system will employ three different types of dual-resonator cavity BPMs, since the accelerator has three different beam pipe apertures. In the injector and main linac (38mm and 16mm aperture), 3.3GHz cavity BPMs will be used, where a low Q of ~40 was chosen to minimize crosstalk of the two bunches*. In the undulators that just have single bunches and 8mm BPM aperture, a higher Q will be chosen. This paper reports on the development status of the SwissFEL BPM system. Synergies as well as differences to the E-XFEL BPM system** will also be highlighted.
* F. Marcellini et al., "Design of Cavity BPM Pickups For SwissFEL", Proc. IBIC'12, Tsukuba, Japan, 2012.
** B. Keil et al., "The European XFEL BPM System", Proc. IPAC'10, Kyoto, Japan, 2010.

Poster TUPC25 [1.074 MB]

TUPC29

Grounded Coplanar Waveguide Transmission Lines as Pickups for Beam Position Monitoring in Particle Accelerators

pick-up, simulation, beam-position, coupling

438

A. Penirschke, A. Angelovski, R. Jakoby
TU Darmstadt, Darmstadt, Germany
C. Gerth, U. Mavrič, D. Nölle, C. Sydlo, S. Vilcins
DESY, Hamburg, Germany

Funding: The work was supported by the MSK group at DESY Hamburg. The authors would like to thank the CST AG for providing the CST Software Package.
Energy beam position monitors (EBPM) based on grounded co-planar waveguide (GCPW) transmission lines have been designed for installation in the dispersive sections of the bunch compressor chicanes at the European XFEL. In combination with beam position monitors at the entrance and exit of the bunch compressor chicanes, measurements of the beam energy with single bunch resolution are feasible. The EBPM consists of transversely mounted stripline pickups in a rectangular beam pipe section. The signal detection for the measurement of the phases of the pulses at each end of the pickups is based on the standard down-conversion and phase detection scheme used for the low-level RF-system. A measurement resolution within the lower micrometer range can be achieved for input signal reflections at the pickup of less than -25 dB at 3 GHz. In this paper, simulation results of a novel pickup geometry utilized with GCPW pickup structures and optimized transitions to perpendicular mounted coaxial connectors are presented. The simulation results exhibit small reflection coefficients with reflected signal components having less than 2% of the peak voltage signal.

TUPC31

New Design of High Order Modes Electronics in MTCA.4 Standard for FLASH and the European XFEL

DESY, beam-position, monitoring, alignment

443

S. Bou Habib, A. Abramowicz
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
N. Baboi, H. Schlarb
DESY, Hamburg, Germany

At free-electron linear accelerators, various High Order Modes (HOM) - both monopole and dipole - are excited. Extensive studies at DESY have shown that monitoring and analysis of some of these modes can be used for different applications including Beam Position Monitors (BPMs) and the reduction of wake-fields, the measurement of the beam phase with-respect-to RF signal in cavities, and the measurement of cavity alignment in the 1.3 GHz cryo-modules. Three frequencies were chosen for further experiments: the 1.3 GHz base frequency from the klystron, the 1.7 GHz dipole mode and the 2.4 GHz monopole mode. In order to realize the monitoring and analysis requirements, very high resolution measurements in amplitude, phase and shape (time resolution) are required for all three frequencies simultaneously. In this paper, we present the new HOM electronics prototype including a microstrip and stripline RF tri-passband filter design and measurements and the specialized MTCA.4 Rear Transition Module for HOM measurements with an ultra-fast high-resolution AMC digitizer.

Poster TUPC31 [1.226 MB]

TUPC33

Femtosecond Stable Laser-to-RF Phase Detection for Optical Synchronization Systems

laser, controls, polarization, monitoring

447

T. Lamb, M.K. Czwalinna, M. Felber, C. Gerth, H. Schlarb, S. Schulz, C. Sydlo, M. Titberidze, F. Zummack
DESY, Hamburg, Germany
E. Janas
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
J. Szewiński
NCBJ, Świerk/Otwock, Poland

Optical reference distributions have become an indispensable asset for femtosecond precision synchronization of free-electron lasers. At FLASH and for the future European XFEL, laser pulses are distributed over large distances in round-trip time stabilized fibers to all critical facility sub-systems. Novel Laser-to-RF phase detectors will be used to provide ultra phase stable and long-term drift free microwave signals for the accelerator RF controls. In this paper, we present the recent progress on the design of a fully integrated and engineered version of the L2RF phase detector, together with first experimental results demonstrating so-far unrivaled performance.

Poster TUPC33 [18.910 MB]

TUPC34

Precision Synchronization of Optical Lasers Based on MTCA.4 Electronics

laser, feedback, DESY, monitoring

451

U. Mavrič, L. Butkowski, H.T. Duhme, M. Felber, M. Fenner, C. Gerth, P. Peier, H. Schlarb, B. Steffen
DESY, Hamburg, Germany
T. Kozak, P. Predki
TUL-DMCS, Łódź, Poland

Optical laser have become an integral part of free-electron laser facilities for the purposes of electron bunch generation, external seeding, diagnostics and pump-probe experiments. The ultra-short electron bunches demand a high timing stability and precision synchronization of the optical lasers. In this paper, we present the proof-of-principle for a laser locking application implemented on a MTCA.4 platform. The system design relies on existing MTCA.4 compliant off-the-shelf modules that are available on the market or have been developed for other applications within the particle accelerator community. Besides performance and cost, we also tried to minimize the number of out-of-crate components. Preliminary measurements of laser locking at the FLASH and REGAE particle accelerators are presented, and an outlook for further system development in the area of laser-to-RF synchronization is given.

TUPC35

Upgrade of the Read-out Electronics for the Energy Beam Position Monitors at FLASH and European XFEL

pick-up, beam-position, DESY, SNR

454

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

The dispersive sections of magnetic bunch compressor chicanes at free-electron lasers are excellent candidates for beam energy measurements. In the rectangular beamline sections of the bunch compressors at FLASH, energy beam position monitors (EBPM) with transversely mounted stripline pickups are installed. In this paper, we present the upgrade of the read-out electronics for signal detection of the EBPM installed at FLASH. The system is based on the MTCA.4 standard and reuses already available MTCA.4 compliant modules. This is also true for gateware and software development which fits into standard MTCA.4 framework development. The performance of the instrument was studied at FLASH during user operation and the results are presented.

WEPC21

Design and Beam Test Results of Button BPMs for the European XFEL

pick-up, BPM, controls, DESY

723

D.M. Treyer, R. Baldinger, R. Ditter, B. Keil, W. Koprek, G. Marinkovic, M. Roggli
PSI, Villigen PSI, Switzerland
D. Lipka, D. Nölle, S. Vilcins
DESY, Hamburg, Germany

Funding: Swiss State Secretariat for Education, Research and Innovation
The European X-ray Free Electron Laser (E-XFEL) will use a total ~300 button BPMs along the whole accelerator, as well as 160 cavity BPMs. The pickups for the button BPMs have been designed by DESY, whereas the electronics has been developed by PSI. This paper gives an overview of the button BPM system, with focus on the RF front end electronics, signal processing, and overall system performance. Measurement results achieved with prototypes installed at FLASH/DESY and at the SwissFEL Injector Test Facility (SITF) are presented. The position noise obtained with button pickups in a 40.5 mm aperture beam pipe is as low as ~11 um at 20 pC bunch charge.

Poster WEPC21 [1.595 MB]

WEPC31

New Design of the 40 GHz Bunch Arrival Time Monitor Using MTCA.4 Electronics at FLASH and for the European XFEL

laser, pick-up, DESY, diagnostics

749

M.K. Czwalinna, C. Gerth, H. Schlarb
DESY, Hamburg, Germany
S. Bou Habib
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
S. Korolczuk, J. Szewiński
NCBJ, Świerk/Otwock, Poland
A. Kuhl
Uni HH, Hamburg, Germany

At free-electron lasers, today's pump-probe experiments and seeding schemes make high demands on the electron bunch timing stability with an arrival time jitter reduction down to the femtosecond level. At FLASH and the upcoming European XFEL, the bunch train structures with their high bunch repetition rates allow for an accurate intra-train stabilisation. To realise longitudinal beam-based feedbacks a reliable and precise arrival time detection over a broad range of bunch charges, which can even change from 1 nC down to 20 pC within a bunch train, is essential. Benefitting from the experience at FLASH, the current bunch arrival time monitors (BAMs), based on detection of RF signals from broad-band pick-ups by use of electro-optic modulators, are further developed to cope with the increased requirements. In this paper, we present the new BAM prototype, including an adapted electro-optical front-end and the latest development of the read-out electronics based on the MTCA.4 platform.

WEPC38

Current Status of Development of Optical Synchronization System for PAL XFEL

laser, FEL, feedback, LCLS

772

C.-K. Min, I. Eom, H.-S. Kang, B.R. Park, S.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea
K. Jung, J. Kim, J. Lim
KAIST, Daejeon, Republic of Korea

Optical synchronization system has been developed for higher quality PAL XFEL with low timing jitter since 2011. In last two years, laboratory test was successfully performed, and test in our accelerator environment is ongoing. In laboratory, we tested the synchronization of RF master oscillator and optical master oscillator, the stabilization of 610 m optical fiber link, and the remote optical-to-RF conversion. We report recent our development results and summarize on-going optical timing project.

Poster WEPC38 [3.366 MB]

WEPC45

Beam Loss Monitoring at the European Spallation Source

beam-losses, ESS, LHC, simulation

795

L. Tchelidze, H. Hassanzadegan, A. Jansson, M. Jarosz
ESS, Lund, Sweden

At the European Spallation Source proton linear accelerator will generate 5 MW protons to be delivered to a target. This high power accelerator will require significant amount of beam instrumentation, among which the beam loss monitoring system is one of the most important for operation. An LHC type ionization chamber will be used with ~54 uC/Gy sensitivity. At most 1.5 mGy/sec radiation levels are expected close to the beam pipe during normal operation, resulting in up to 80 nA current signal in detectors. Loss monitor electronics is designed to be able to measure currents as little as 1% of the expected current up to as much as 1% of the total beam loss, thus ~800 pA – few mA. In order to study beam loss pattern along the accelerator a coherent model of the whole machine is created for the purposes of Monte Carlo particle transport simulations. Data obtained using the model will be stored in a database together with the initial beam loss conditions. The contents of the database will then be processed using custom neural network algorithms to optimize number and position of the loss monitors and to provide reference on the beam loss localization during operation of the machine.

Poster WEPC45 [1.784 MB]

WEPF03

Scintillating Screen Monitors for Transverse Electron Beam Profile Diagnostics at the European XFEL

electron, OTR, transverse, DESY

807

Ch. Wiebers, M. Holz, G. Kube, D. Nölle, G. Priebe, H.-Ch. Schröder
DESY, Hamburg, Germany

Transverse beam profile diagnostics in modern electron linear accelerators like FELs or injector LINACs are mainly based on optical transition radiation (OTR) as standard technique which is observed in backward direction when a charged particle beam crosses the boundary between two media with different dielectric properties. The experience from modern LINAC based 4th generation light sources shows that OTR diagnostics might fail because of coherence effects in the OTR emission process. As a consequence, for the European XFEL which is currently under construction in Hamburg, transverse beam profile measurements are based on scintillating screen monitors. The LYSO:Ce screens are oriented such that coherent OTR generated at the screen boundaries will be geometrically suppressed. An additional advantage is that the imaging optics operate in Scheimpflug condition thus adjusting the plane of sharp focus with respect to the CCD chip and significantly increasing the apparent depth of field. This report gives an overview of the measuring principle and the monitor setup together with results of laboratory test measurements and a first prototype test at FLASH (DESY, Hamburg).

WEPF25

Resonator for Charge Measurement at REGAE

DESY, controls, PITZ, LEFT

872

D. Lipka, J. Lund-Nielsen, M. Seebach
DESY, Hamburg, Germany

A resonator has been developed for the diagnostics of dark current and charge measurements at the European XFEL, FLASH and PITZ. The first induced monopole mode TM01 at 1.3 GHz from charged bunches is used to detect the dark current and charge with high resolution at these accelerators. At REGAE this resonator with electronics is installed to detect the bunch charge because charges below pC are used and this device can resolve it non-destructively. The same electronics as for the dark current and charge measurement is used and the resolution is measured to be 2.3 fC for 200 fC.

Poster WEPF25 [0.822 MB]