IBIC2017 - Classification: 4 Time-Resolved Diagnostics and Synchronization

Paper	Title	Page
TU1AB1	Precision Large Scale Synchronization System at the European XFEL
	C. Sydlo DESY, Hamburg, Germany
	Accurate timing synchronization on the femtosecond scale is an essential installation for time-resolved experiments at free-electron lasers such as FLASH and the upcoming European XFEL. The European XFEL imposes greater requirements due to its exceptional specifications, large number of stabilized optical fibers and a total length of 3.4km. The development towards a reliable system, their results and the current status of the optical synchronization system at the European XFEL are presented.
	Slides TU1AB1 [7.149 MB]
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TU1AB2	High Repetition-Rate Electro-optic Sampling: Recent Studies Using Photonic Time-Stretch	121
	S. Bielawski, M. Le Parquier PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France E. Blomley, E. Bründermann, S. Funkner, A.-S. Müller, M.J. Nasse, G. Niehues, M. Schuh, P. Schönfeldt, J.L. Steinmann, S.W. Walter KIT, Eggenstein-Leopoldshafen, Germany J.B. Brubach, L. Manceron, P. Roy, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France C. Evain, C. Szwaj PhLAM/CERLA, Villeneuve d'Ascq, France N. Hiller PSI, Villigen PSI, Switzerland E. Roussel Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	Single-shot electro-optic sampling (EOS) is a powerful characterization tool for monitoring the shape of electron bunches, and coherent synchrotron radiation pulses. For reaching high acquisition rates, an efficient possibility consists to associate classic EOS systems with the so-called photonic time-stretch technique [1]. We present recent results obtained at SOLEIL and ANKA using this strategy. In particular, we show how a high sensitivity variant of photonic time stretch [2] EOS enabled to monitor the CSR pulses emitted by short electron bunches at SOLEIL [3]. We could thus confirm in a very direct way the theories predicting an interplay between two physical processes. Below a critical bunch charge, we observe a train of identical THz pulses stemming from the shortness of the electron bunches. Above this threshold, CSR emission is dominated by drifting structures appearing through spontaneous self-organization. We also consider the association of time-stretch and EOS for recording electron bunch near fields at high repetition rate. We present preliminary results obtained at ANKA, aiming at recording the electron bunch shape evolution during the microbunching instability. [1] F. Coppinger et al. IEEE Trans. Microwave Theory Tech. 47, 1309 (1999). [2] C. Szwaj et al., Rev. Sci. Instruments 87, 103111 (2016). [3] C. Evain et al., Phys. Rev. Lett. 118, 054801 (2017).
	Slides TU1AB2 [72.925 MB]
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TU1AB3	The Optical Dissector Bunch Length Measurements at the Metrology Light Source	125
	D. Malyutin, A.N. Matveenko, M. Ries HZB, Berlin, Germany O. Anchugov, S.A. Krutikhin, O.I. Meshkov BINP SB RAS, Novosibirsk, Russia V.L. Dorokhov BINP, Novosibirsk, Russia
	The bunch longitudinal profile measurements using an optical dissector are introduced in the paper. The principles of the dissector operation are briefly discussed. The first measurements using the optical dissector at the Metrology Light Source are presented. Results are analyzed and compared with the bunch profiles from the streak camera measurements. Measurement errors and limitations of the both methods are estimated. Possible applications for the presented technique are discussed.
	Slides TU1AB3 [1.997 MB]
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TU2AB1	Integrated Photonics to the Rescue of Femtosecond Beam Diagnostics	129
	F.X. Kärtner CFEL, Hamburg, Germany
	Beam instrumentations have always been using results from neighbor communities. Over the last 10 years, a number of beam instruments and systems have successfully adopted optical solutions, pushing performances from ps to fs, exploiting optical set-ups or photonic components. In a positive loop, new ideas and original solutions have been bouncing back and forth from electronics to optical and from copper coax to optical fibers. Next step is moving to photonic integrated circuits, i.e. from single function photonic components to complete on-chip optical systems which are now becoming available, or will shortly be. This tutorial covers recent advances in integrated optics, that may have great impact on future beam accelerator diagnostic instruments and systems. Topics include: High sensitivity and high resolution integrated balanced cross-correlators for sub-femtosecond timing distribution, integrated femtosecond lasers, frequency combs and optical signal synthesis, optically assisted analog-to-digital conversion for high-speed and high-resolution down-conversion and sampling.
	Slides TU2AB1 [10.108 MB]
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TU2AB3	Single-Shot Longitudinal Beam Profile and Terahertz Diagnostics at MHz - Towards GHz-Rates with High-Throughput Electronics	136
	M. Caselle, B.M. Balzer, M. Brosi, E. Bründermann, S. Funkner, B. Kehrer, A.-S. Müller, M.J. Nasse, G. Niehues, M.M. Patil, L. Rota, M. Schuh, P. Schönfeldt, J.L. Steinmann, M. Weber, M. Yan KIT, Eggenstein-Leopoldshafen, Germany G. BORGHI,, M. Boscardin, S. Ronchin FBK, Trento, Italy
	Accelerators with high bunch-repetition rates mandate high-throughput detector electronics to diagnose each individual bunch. KALYPSO with a 256-pixel detector line-array integrated in an fs laser-based electro-optical set-up allows longitudinal bunch profiling with sub-ps resolution as demonstrated at the storage ring ANKA for single-bunch mode operation at 2.7 MHz and also at the Eu-XFEL with a 4.5-MHz micro-bunch train. Improvements will enhance fs-time accuracy, reduce noise, and increase frame-rate. A custom front-end with an application-specific integrated circuit (ASIC) has been developed to operate with 10-MHz frame-rates at low noise. Several linear arrays with up to 1024 pixel and smaller pixel pitch were submitted for production. The development of a low-gain avalanche diode (LGAD) sensor will further improve the time resolution. Detector data is transmitted in the DAQ framework to external GPU-based clusters and processed in real-time at 7 Gbytes/s with a few μs latency. For beam dynamics studies we also develop KAPTURE capable to analyze terahertz detector pulses at GHz-repetition rates. These developments open new windows in beam diagnostics of modern accelerators.
	Slides TU2AB3 [1.906 MB]
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TUPCC01	Current Status of CVD Diamond Based Beam Detector Developments at the S-DALINAC	150
	A. Rost, T. Galatyuk TU Darmstadt, Darmstadt, Germany J. Pietraszko GSI, Darmstadt, Germany
	Funding: This work has been supported by the DFG through GRK 2128 and VH-NG-823. For future experiments with the HADES and CBM detectors at FAIR in Darmstadt, a radiation hard and fast beam detector is required. The beam detector has to perform precise T0 measurements (σ_T0 < 50 ps) and should offer beam monitoring capabilities. These tasks can be fulfilled by utilizing single-crystal Chemical Vapor Deposition (scCVD) diamond based detectors. For research and development of such detectors, a test set-up is currently installed at the Superconducting Darmstadt Electron Linear Accelerator (S-DALINAC) of TU Darmstadt. In this contribution the concept and the performance of a prototype beam monitoring system will be discussed. Furthermore the preparatory work of the test set-up at the S-DALINAC will be addressed.
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TUPCC03	Online Longitudinal Bunch Profile and Slice Emittance Diagnostics at the European XFEL	153
	C. Gerth, B. Beutner, O. Hensler, F. Obier, M. Scholz, M. Yan DESY, Hamburg, Germany
	The longitudinal current profile and slice emittance are important bunch parameters for the operation of an X-ray free-electron laser. At the European XFEL, dedicated diagnostic sections equipped with transverse deflecting RF structures (TDS) have been installed for the control and optimisation of these parameters. Travelling-wave TDS in combination with fast kicker magnets and off-axis screens allow for the study of individual bunches without affecting the other bunches in the super-conducting linear accelerator which can generate bunch trains of up to 2700 bunches at 4.5 MHz within 600 microsecond RF pulses at a repetition rate of 10 Hz. The measurement of the slice emittance is realised in a static F0D0 lattice equipped with four individual screen stations. Variations of the longitudinal bunch profile or slice emittance along the bunch train may lead to degraded FEL performance for parts of the train which reduces the effective available number of bunches for FEL operation. By gradually adjusting the timing, individual bunches along the bunch train can be measured in order to optimise the overall beam parameters for all bunches in the train.
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TUPCC05	Concept for the Minimization of the Electron Bunch Arrival-Time Jitter between Femtosecond Laser Pulses and Electron Bunches for Laser-Driven Plasma Wakefield Accelerators	157
	S. Mattiello, A. Penirschke THM, Friedberg, Germany H. Schlarb DESY, Hamburg, Germany
	Funding: The work of S. Mattiello is supported by the German Federal Ministry of Education and Research (BMBF) under contract no. 05K16ROA. Using laser driven plasma wakefield accelerators, the synchronization between electron bunch and the ultrashort laser is crucial to obtain an stable acceleration. In order to minimize the electron bunch arrival-time jitter, the development of a new shot to shot feedback system with a time resolution of less than §I{1}{\femto\second} is planned. As a first step, stable Terahertz (THz) pulses should be performed by optical rectification of high energy femtosecond laser pulses in a nonlinear crystal. It is planed that the generated THz pulses will energy modulate the electron bunches shot to shot before the plasma to achieve the time resolution of 1fs. The selection of the nonlinear material is a critical aspect for the development of laser driven THz sources. In this contribution we investigate systematically the influence of the optical properties, and in particular adsorption coeffient, of lithium niobate crystal on the conversion efficiency of the generation of THz pulses.
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TUPCC06	Injection and Bunch Length Studies at the BESSY II Storage Ring	161
	D. Malyutin, T. Atkinson, P. Goslawski, A. Jankowiak, A.N. Matveenko, M. Ries HZB, Berlin, Germany
	To improve the injection process into the BESSY II storage ring and allow for high injection efficiencies in all operational modes, one needs to know the development of the bunch length during acceleration in the booster synchrotron up to the extraction point. It will become even more important for the future BESSY VSR upgrade when high efficiency injection into much shorter RF buckets needs to be guaranteed. Measurements of bunch phase and energy during injection in the storage ring are presented. Studies of the bunch length evolution during the energy ramp of the booster are described. Results are compared with numerical simulations and discussed.
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TUPCC08	Improving the Sensitivity of Existing Electro-Optic Sampling Setups by Adding Brewster Plates: Tests of the Strategy at SOLEIL	164
	S. Bielawski, M. Le Parquier PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France J.B. Brubach, L. Manceron, P. Roy, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France C. Evain, C. Szwaj PhLAM/CERLA, Villeneuve d'Ascq, France
	Funding: ERDF/CPER photonics for society. LABEX CEMPI Project (No. ANR-11-LABX-0007). HPC resources from GENCI TGCC/IDRIS (Grant Nos. i2015057057 and i2016057057). For improving the sensitivity of electro-optic sampling (EOS), several techniques are used. Operation of the set of polarizing elements "close to extinction" is a technique used routinely for obtaining high responsivity (i.e., a large output signal for a given input electric field). This technique is widely used for monitoring electron bunches in linear accelerators and FELs. We show that a simple modification of these EOS systems enables to increase further the SNR, by cancelling out the laser noise. The idea is to introduce a set of Brewster plates, following the idea Ahmed, Savolainen and Hamm [1] in the EOS path, and performing balanced detection. We present detailed tests of this type of upgrade on the PhLAM-SOLEIL EOS system, destined to studies of THz CSR pulse dynamics [2]. [1] Ahmed et al, Rev. Sci. Instrum. 85, 013114 (2014) [2] Szwaj et al., Review of Scientific Instruments 87, 103111 (2016)
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TUPCC09	Electron Bunch Pattern Monitoring via Single Photon Counting at SPEAR3	168
	B. Xu, E. Carranza, A. Chen, S. Condamoor, W.J. Corbett, A.S. Fisher SLAC, Menlo Park, California, USA
	In recent years the synchrotron radiation program at SPEAR3 has moved increasingly toward laser/x-ray pump-probe experiments which utilize a single timing ‘probe' bunch isolated by 50ns dark space ahead and behind the bunch. In order to quantify bunch purity in the region near the timing bunch, time-correlated single-photon counting is used. In this paper we investigate methods to optimize data acquisition speed and improve measurement resolution in the region near the timing bunch through data analysis and fast signal gating. Integration of the measured data into the EPICS database is reported.
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TUPCC10	Time-Resolved Electron-Bunch Diagnostics Using Transverse Wakefields	172
	J. Wang, D. Mihalcea, P. Piot Northern Illinois University, DeKalb, Illinois, USA
	Funding: Work supported by the DOE award DE-SC0011831 to NIU. Fermilab is operated by the Fermi Research Alliance, LLC for the DOE under contract DE-AC02-07CH11359. The development of future free electron lasers (FELs) requires reliable time-resolved measurement of variable ultra-short electron-bunchs characteristics. A possible technique is to streak the bunch in the transverse direction by means of time-dependent external fields. In this paper we explore the possible use of self-generated electromagnetic fields . A passive deflector, consisting of a dielectric-lined waveguide, is used to produce wakefields that impart a time-dependent transverse kick to the relativistic electron bunch passing off-axis. We investigate the technique and its performances and explore its possible application at the Fermilab Accelerator Science & Technology (FAST) facility. S. Bettoni, et al., Phys. Rev. Accel. & Beam, 19, 021304 (2016)
	Poster TUPCC10 [0.387 MB]
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TUPCC12	Bunch Shape Monitors for Modern Ion Linacs	176
	S.A. Gavrilov, A. Feschenko RAS/INR, Moscow, Russia
	In recent years several Bunch Shape Monitors were designed for new modern ion linacs, such as Linac4 CERN, Proton and CW-linac FAIR GSI, FRIB MSU, ESS ERIC. Each of these accelerators has its own requirements for a phase resolution, mechanical design and operating conditions of the monitor. An overview of the most interesting design and operation features of different monitors is presented. Some results of laboratory tests and on-site beam measurements are discussed.
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TUPCC13	Design and Development of Bunch Shape Monitor for FRIB MSU	179
	S.A. Gavrilov, A. Feschenko RAS/INR, Moscow, Russia
	Bunch Shape Monitor was developed and tested in INR RAS for The Facility for Rare Isotope Beams to fulfil the requirements of a half a degree phase resolution for 80.5 MHz FRIB operating frequency. The configuration of the λ/4-type RF-deflector based on the parallel wire lines with the shorting jumper and capacitive plates was selected. Special dual correcting magnet is foreseen to compensate a possible influence of external magnetic fields. Peculiarities of the design and development process are described. Results of laboratory tests are presented.
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TUPCC15	Design and Commissioning of the Bunch Arrival-Time Monitor for SwissFEL	182
	V.R. Arsov, F. Buechi, P. Chevtsov, M. Dach, M. Heiniger, S. Hunziker, M.G. Kaiser, R. Kramert, A. Romann, V. Schlott PSI, Villigen PSI, Switzerland
	The Bunch Arrival-Time Monitor for SwissFEL (BAM) is based on the concept, which was successfully tested at the SwissFEL Test Facility [1]. During the gap between the SITF decommissioning and the start of SwissFEL, all key components underwent design improvement. In this paper, we report on these new developments, including the mechanical design of the BAM-Pickup and RF-front end, the electro-optical front end (BAM-Box), the data acquisition front end, the new expert- and user applications. We have developed concepts and tested hardware for Bunch-ID stamping of signals, relevant for the extraction of the arrival-time information. Presently two complete systems are installed and being commissioned at SwissFEL - one in the injector gun and one between the two bunch compressors. We report on the ongoing first commissioning results. [1] T. Schietinger et al., Commissioning experience and beam physics measurements at SITF, Phys. Rev. Accel. and Beams, 19, 100702 (2016)
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TUPCC16	Status of the THz Streaking Experiment with Split Ring Resonators at FLUTE	186
	V. Schlott, M.M. Dehler, R. Ischebeck, M. Moser PSI, Villigen PSI, Switzerland E. Bründermann, S. Funkner, A.-S. Müller, M.J. Nasse, G. Niehues, R. Ruprecht, T. Schmelzer, M. Schuh, M. Schwarz, M. Yan KIT, Karlsruhe, Germany T. Feurer, M. Hayati, Z. Ollmann, R. Tarkeshian Universität Bern, Institute of Applied Physics, Bern, Switzerland
	THz streaking with split ring resonators (SRR) promise ultra-high (sub-femtosecond) temporal resolution even for relativistic electron bunches. A proof-of-principle experiment in collaboration between the University of Bern, the Paul Scherrer Institute (PSI) and the Karlsruhe Institute of Technology (KIT) is currently prepared at the FLUTE facility (Ferninfrarot Linac und Test Experiment) at KIT. Most of the critical components have been designed, tested and set-up in the 7 MeV diagnostics part of FLUTE. In this contribution we will present an update on the experimental set-up and report on SRR configurations which have been optimized for highest THz deflection, while simultaneously accounting for the restrictions of the manufacturing process. Test measurements characterizing the SRR samples and the THz source, which has been matched to the FLUTE gun laser, will also be presented.
	Poster TUPCC16 [0.539 MB]
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TUPCC17	Ultra-Stable Fiber-Optic Reference Distribution for SwissFEL C-Band Linacs Based on S-Band Radio-Over-Fiber Links and Frequency Doubler / Power Amplifiers	189
	S. Hunziker, V.R. Arsov, F. Buechi, M. Dach, M. Heiniger, M.G. Kaiser, R. Kramert, A. Romann, V. Schlott PSI, Villigen PSI, Switzerland
	The reference distribution for the SwissFEL accelerator is based on ultra-stable Libera Sync 3 fiber-optic links operating at 3 GHz with <2.4fs added timing jitter. While s-band injector RF stations are directly supplied with these actively stabilized reference signals at 2.9988GHz, the same 3 GHz optical links are used to transmit reference signals at 2.856GHz (half c-band frequency) to the c-band LINACs, combined with a frequency doubler-amplifier at the link end. A novel zero AM/PM-conversion frequency-doubler and an amplitude-/phase-controlled power amplifier have been implemented in a compact 1HU 19inch unit. Key design concepts and measurement results will be presented. It will be shown that this inexpensive doubler-amplifier system adds only insignificant jitter and drift to the transmitted reference signals. As the same actively stabilized 3GHz links can be used for s- and c- band RF stations, development of a more expensive 6GHz fiber-optic link could be avoided. A higher quantity of the same link type can thus be manufactured and the number of spares is reduced as only one link type is utilized for the SwissFEL injector and LINAC RF reference signals.
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TUPCC18	Beam Arrival Time Measurement at SXFEL	193
	S.S. Cao, J. Chen, Y.B. Leng SINAP, Shanghai, People's Republic of China R.X. Yuan SSRF, Shanghai, People's Republic of China
	Shanghai Soft X-ray Free Electron Laser (SXFEL) is a fourth-generation light source which could provide coherent X-rays for various scientific researches. One of the key issues of its operation is the measurement of bunch arrival time which is important for the synchronization of a bunch and seeded laser. The measurement utilized a newly designed beam arrival time monitor (BAM) which contains two cavities at a different frequency. Thus a new way, dual-cavities mixing method, is applied in this experiment to evaluate the beam arrival time resolution. In this paper, we presented the scheme and different measured resolution of various measurement methods and evaluated the stability of the new monitor.
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WE2AB1	Beam Diagnostics Overview and Challenges for Low-Energy, Low-Intensity Beams
	C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Low-energetic ion and antimatter beams are very at-tractive for a number of fundamental studies. The diagnostics of such beams, however, is a challenge due to low currents down to only a few thousands of parti-cles per second and significant fraction of energy loss in matter at keV beam energies. On the example of the ELENA storage ring which is being commissioned at CERN this year, this paper summarizes the essential beam diagnostics required to fully characterize low energy, low intensity ion beams. THis includes beam-profile monitors based on scintillating screens and secondary electron emission, sensitive Faraday cups for absolute intensity measurements, and capacitive pickups for beam position monitoring as basic diagnostics. More advanced diagnostics options in-clude gas based beam profile monitors and ultra-sensitive beam current transformers using SQUID technology.
	Slides WE2AB1 [4.519 MB]
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Paper

Title

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TU1AB1

Precision Large Scale Synchronization System at the European XFEL

C. Sydlo
DESY, Hamburg, Germany

Accurate timing synchronization on the femtosecond scale is an essential installation for time-resolved experiments at free-electron lasers such as FLASH and the upcoming European XFEL. The European XFEL imposes greater requirements due to its exceptional specifications, large number of stabilized optical fibers and a total length of 3.4km. The development towards a reliable system, their results and the current status of the optical synchronization system at the European XFEL are presented.

Slides TU1AB1 [7.149 MB]

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TU1AB2

High Repetition-Rate Electro-optic Sampling: Recent Studies Using Photonic Time-Stretch

121

S. Bielawski, M. Le Parquier
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
E. Blomley, E. Bründermann, S. Funkner, A.-S. Müller, M.J. Nasse, G. Niehues, M. Schuh, P. Schönfeldt, J.L. Steinmann, S.W. Walter
KIT, Eggenstein-Leopoldshafen, Germany
J.B. Brubach, L. Manceron, P. Roy, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France
C. Evain, C. Szwaj
PhLAM/CERLA, Villeneuve d'Ascq, France
N. Hiller
PSI, Villigen PSI, Switzerland
E. Roussel
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

Single-shot electro-optic sampling (EOS) is a powerful characterization tool for monitoring the shape of electron bunches, and coherent synchrotron radiation pulses. For reaching high acquisition rates, an efficient possibility consists to associate classic EOS systems with the so-called photonic time-stretch technique [1]. We present recent results obtained at SOLEIL and ANKA using this strategy. In particular, we show how a high sensitivity variant of photonic time stretch [2] EOS enabled to monitor the CSR pulses emitted by short electron bunches at SOLEIL [3]. We could thus confirm in a very direct way the theories predicting an interplay between two physical processes. Below a critical bunch charge, we observe a train of identical THz pulses stemming from the shortness of the electron bunches. Above this threshold, CSR emission is dominated by drifting structures appearing through spontaneous self-organization. We also consider the association of time-stretch and EOS for recording electron bunch near fields at high repetition rate. We present preliminary results obtained at ANKA, aiming at recording the electron bunch shape evolution during the microbunching instability.
[1] F. Coppinger et al. IEEE Trans. Microwave Theory Tech. 47, 1309 (1999).
[2] C. Szwaj et al., Rev. Sci. Instruments 87, 103111 (2016).
[3] C. Evain et al., Phys. Rev. Lett. 118, 054801 (2017).

Slides TU1AB2 [72.925 MB]

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TU1AB3

The Optical Dissector Bunch Length Measurements at the Metrology Light Source

125

D. Malyutin, A.N. Matveenko, M. Ries
HZB, Berlin, Germany
O. Anchugov, S.A. Krutikhin, O.I. Meshkov
BINP SB RAS, Novosibirsk, Russia
V.L. Dorokhov
BINP, Novosibirsk, Russia

The bunch longitudinal profile measurements using an optical dissector are introduced in the paper. The principles of the dissector operation are briefly discussed. The first measurements using the optical dissector at the Metrology Light Source are presented. Results are analyzed and compared with the bunch profiles from the streak camera measurements. Measurement errors and limitations of the both methods are estimated. Possible applications for the presented technique are discussed.

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TU2AB1

Integrated Photonics to the Rescue of Femtosecond Beam Diagnostics

129

F.X. Kärtner
CFEL, Hamburg, Germany

Beam instrumentations have always been using results from neighbor communities. Over the last 10 years, a number of beam instruments and systems have successfully adopted optical solutions, pushing performances from ps to fs, exploiting optical set-ups or photonic components. In a positive loop, new ideas and original solutions have been bouncing back and forth from electronics to optical and from copper coax to optical fibers. Next step is moving to photonic integrated circuits, i.e. from single function photonic components to complete on-chip optical systems which are now becoming available, or will shortly be. This tutorial covers recent advances in integrated optics, that may have great impact on future beam accelerator diagnostic instruments and systems. Topics include: High sensitivity and high resolution integrated balanced cross-correlators for sub-femtosecond timing distribution, integrated femtosecond lasers, frequency combs and optical signal synthesis, optically assisted analog-to-digital conversion for high-speed and high-resolution down-conversion and sampling.

Slides TU2AB1 [10.108 MB]

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TU2AB3

Single-Shot Longitudinal Beam Profile and Terahertz Diagnostics at MHz - Towards GHz-Rates with High-Throughput Electronics

136

M. Caselle, B.M. Balzer, M. Brosi, E. Bründermann, S. Funkner, B. Kehrer, A.-S. Müller, M.J. Nasse, G. Niehues, M.M. Patil, L. Rota, M. Schuh, P. Schönfeldt, J.L. Steinmann, M. Weber, M. Yan
KIT, Eggenstein-Leopoldshafen, Germany
G. BORGHI,, M. Boscardin, S. Ronchin
FBK, Trento, Italy

Accelerators with high bunch-repetition rates mandate high-throughput detector electronics to diagnose each individual bunch. KALYPSO with a 256-pixel detector line-array integrated in an fs laser-based electro-optical set-up allows longitudinal bunch profiling with sub-ps resolution as demonstrated at the storage ring ANKA for single-bunch mode operation at 2.7 MHz and also at the Eu-XFEL with a 4.5-MHz micro-bunch train. Improvements will enhance fs-time accuracy, reduce noise, and increase frame-rate. A custom front-end with an application-specific integrated circuit (ASIC) has been developed to operate with 10-MHz frame-rates at low noise. Several linear arrays with up to 1024 pixel and smaller pixel pitch were submitted for production. The development of a low-gain avalanche diode (LGAD) sensor will further improve the time resolution. Detector data is transmitted in the DAQ framework to external GPU-based clusters and processed in real-time at 7 Gbytes/s with a few μs latency. For beam dynamics studies we also develop KAPTURE capable to analyze terahertz detector pulses at GHz-repetition rates. These developments open new windows in beam diagnostics of modern accelerators.

Slides TU2AB3 [1.906 MB]

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TUPCC01

Current Status of CVD Diamond Based Beam Detector Developments at the S-DALINAC

150

A. Rost, T. Galatyuk
TU Darmstadt, Darmstadt, Germany
J. Pietraszko
GSI, Darmstadt, Germany

Funding: This work has been supported by the DFG through GRK 2128 and VH-NG-823.
For future experiments with the HADES and CBM detectors at FAIR in Darmstadt, a radiation hard and fast beam detector is required. The beam detector has to perform precise T0 measurements (σ_T0 < 50 ps) and should offer beam monitoring capabilities. These tasks can be fulfilled by utilizing single-crystal Chemical Vapor Deposition (scCVD) diamond based detectors. For research and development of such detectors, a test set-up is currently installed at the Superconducting Darmstadt Electron Linear Accelerator (S-DALINAC) of TU Darmstadt. In this contribution the concept and the performance of a prototype beam monitoring system will be discussed. Furthermore the preparatory work of the test set-up at the S-DALINAC will be addressed.

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TUPCC03

Online Longitudinal Bunch Profile and Slice Emittance Diagnostics at the European XFEL

153

C. Gerth, B. Beutner, O. Hensler, F. Obier, M. Scholz, M. Yan
DESY, Hamburg, Germany

The longitudinal current profile and slice emittance are important bunch parameters for the operation of an X-ray free-electron laser. At the European XFEL, dedicated diagnostic sections equipped with transverse deflecting RF structures (TDS) have been installed for the control and optimisation of these parameters. Travelling-wave TDS in combination with fast kicker magnets and off-axis screens allow for the study of individual bunches without affecting the other bunches in the super-conducting linear accelerator which can generate bunch trains of up to 2700 bunches at 4.5 MHz within 600 microsecond RF pulses at a repetition rate of 10 Hz. The measurement of the slice emittance is realised in a static F0D0 lattice equipped with four individual screen stations. Variations of the longitudinal bunch profile or slice emittance along the bunch train may lead to degraded FEL performance for parts of the train which reduces the effective available number of bunches for FEL operation. By gradually adjusting the timing, individual bunches along the bunch train can be measured in order to optimise the overall beam parameters for all bunches in the train.

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TUPCC05

Concept for the Minimization of the Electron Bunch Arrival-Time Jitter between Femtosecond Laser Pulses and Electron Bunches for Laser-Driven Plasma Wakefield Accelerators

157

S. Mattiello, A. Penirschke
THM, Friedberg, Germany
H. Schlarb
DESY, Hamburg, Germany

Funding: The work of S. Mattiello is supported by the German Federal Ministry of Education and Research (BMBF) under contract no. 05K16ROA.
Using laser driven plasma wakefield accelerators, the synchronization between electron bunch and the ultrashort laser is crucial to obtain an stable acceleration. In order to minimize the electron bunch arrival-time jitter, the development of a new shot to shot feedback system with a time resolution of less than §I{1}{\femto\second} is planned. As a first step, stable Terahertz (THz) pulses should be performed by optical rectification of high energy femtosecond laser pulses in a nonlinear crystal. It is planed that the generated THz pulses will energy modulate the electron bunches shot to shot before the plasma to achieve the time resolution of 1fs. The selection of the nonlinear material is a critical aspect for the development of laser driven THz sources. In this contribution we investigate systematically the influence of the optical properties, and in particular adsorption coeffient, of lithium niobate crystal on the conversion efficiency of the generation of THz pulses.

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TUPCC06

Injection and Bunch Length Studies at the BESSY II Storage Ring

161

D. Malyutin, T. Atkinson, P. Goslawski, A. Jankowiak, A.N. Matveenko, M. Ries
HZB, Berlin, Germany

To improve the injection process into the BESSY II storage ring and allow for high injection efficiencies in all operational modes, one needs to know the development of the bunch length during acceleration in the booster synchrotron up to the extraction point. It will become even more important for the future BESSY VSR upgrade when high efficiency injection into much shorter RF buckets needs to be guaranteed. Measurements of bunch phase and energy during injection in the storage ring are presented. Studies of the bunch length evolution during the energy ramp of the booster are described. Results are compared with numerical simulations and discussed.

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TUPCC08

Improving the Sensitivity of Existing Electro-Optic Sampling Setups by Adding Brewster Plates: Tests of the Strategy at SOLEIL

164

S. Bielawski, M. Le Parquier
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
J.B. Brubach, L. Manceron, P. Roy, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France
C. Evain, C. Szwaj
PhLAM/CERLA, Villeneuve d'Ascq, France

Funding: ERDF/CPER photonics for society. LABEX CEMPI Project (No. ANR-11-LABX-0007). HPC resources from GENCI TGCC/IDRIS (Grant Nos. i2015057057 and i2016057057).
For improving the sensitivity of electro-optic sampling (EOS), several techniques are used. Operation of the set of polarizing elements "close to extinction" is a technique used routinely for obtaining high responsivity (i.e., a large output signal for a given input electric field). This technique is widely used for monitoring electron bunches in linear accelerators and FELs. We show that a simple modification of these EOS systems enables to increase further the SNR, by cancelling out the laser noise. The idea is to introduce a set of Brewster plates, following the idea Ahmed, Savolainen and Hamm [1] in the EOS path, and performing balanced detection. We present detailed tests of this type of upgrade on the PhLAM-SOLEIL EOS system, destined to studies of THz CSR pulse dynamics [2].
[1] Ahmed et al, Rev. Sci. Instrum. 85, 013114 (2014)
[2] Szwaj et al., Review of Scientific Instruments 87, 103111 (2016)

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TUPCC09

Electron Bunch Pattern Monitoring via Single Photon Counting at SPEAR3

168

B. Xu, E. Carranza, A. Chen, S. Condamoor, W.J. Corbett, A.S. Fisher
SLAC, Menlo Park, California, USA

In recent years the synchrotron radiation program at SPEAR3 has moved increasingly toward laser/x-ray pump-probe experiments which utilize a single timing ‘probe' bunch isolated by 50ns dark space ahead and behind the bunch. In order to quantify bunch purity in the region near the timing bunch, time-correlated single-photon counting is used. In this paper we investigate methods to optimize data acquisition speed and improve measurement resolution in the region near the timing bunch through data analysis and fast signal gating. Integration of the measured data into the EPICS database is reported.

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TUPCC10

Time-Resolved Electron-Bunch Diagnostics Using Transverse Wakefields

172

J. Wang, D. Mihalcea, P. Piot
Northern Illinois University, DeKalb, Illinois, USA

Funding: Work supported by the DOE award DE-SC0011831 to NIU. Fermilab is operated by the Fermi Research Alliance, LLC for the DOE under contract DE-AC02-07CH11359.
The development of future free electron lasers (FELs) requires reliable time-resolved measurement of variable ultra-short electron-bunchs characteristics. A possible technique is to streak the bunch in the transverse direction by means of time-dependent external fields. In this paper we explore the possible use of self-generated electromagnetic fields *. A passive deflector, consisting of a dielectric-lined waveguide, is used to produce wakefields that impart a time-dependent transverse kick to the relativistic electron bunch passing off-axis. We investigate the technique and its performances and explore its possible application at the Fermilab Accelerator Science & Technology (FAST) facility.
* S. Bettoni, et al., Phys. Rev. Accel. & Beam, 19, 021304 (2016)

Poster TUPCC10 [0.387 MB]

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TUPCC12

Bunch Shape Monitors for Modern Ion Linacs

176

S.A. Gavrilov, A. Feschenko
RAS/INR, Moscow, Russia

In recent years several Bunch Shape Monitors were designed for new modern ion linacs, such as Linac4 CERN, Proton and CW-linac FAIR GSI, FRIB MSU, ESS ERIC. Each of these accelerators has its own requirements for a phase resolution, mechanical design and operating conditions of the monitor. An overview of the most interesting design and operation features of different monitors is presented. Some results of laboratory tests and on-site beam measurements are discussed.

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TUPCC13

Design and Development of Bunch Shape Monitor for FRIB MSU

179

S.A. Gavrilov, A. Feschenko
RAS/INR, Moscow, Russia

Bunch Shape Monitor was developed and tested in INR RAS for The Facility for Rare Isotope Beams to fulfil the requirements of a half a degree phase resolution for 80.5 MHz FRIB operating frequency. The configuration of the λ/4-type RF-deflector based on the parallel wire lines with the shorting jumper and capacitive plates was selected. Special dual correcting magnet is foreseen to compensate a possible influence of external magnetic fields. Peculiarities of the design and development process are described. Results of laboratory tests are presented.

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TUPCC15

Design and Commissioning of the Bunch Arrival-Time Monitor for SwissFEL

182

V.R. Arsov, F. Buechi, P. Chevtsov, M. Dach, M. Heiniger, S. Hunziker, M.G. Kaiser, R. Kramert, A. Romann, V. Schlott
PSI, Villigen PSI, Switzerland

The Bunch Arrival-Time Monitor for SwissFEL (BAM) is based on the concept, which was successfully tested at the SwissFEL Test Facility [1]. During the gap between the SITF decommissioning and the start of SwissFEL, all key components underwent design improvement. In this paper, we report on these new developments, including the mechanical design of the BAM-Pickup and RF-front end, the electro-optical front end (BAM-Box), the data acquisition front end, the new expert- and user applications. We have developed concepts and tested hardware for Bunch-ID stamping of signals, relevant for the extraction of the arrival-time information. Presently two complete systems are installed and being commissioned at SwissFEL - one in the injector gun and one between the two bunch compressors. We report on the ongoing first commissioning results.
[1] T. Schietinger et al., Commissioning experience and beam physics measurements at SITF, Phys. Rev. Accel. and Beams, 19, 100702 (2016)

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TUPCC16

Status of the THz Streaking Experiment with Split Ring Resonators at FLUTE

186

V. Schlott, M.M. Dehler, R. Ischebeck, M. Moser
PSI, Villigen PSI, Switzerland
E. Bründermann, S. Funkner, A.-S. Müller, M.J. Nasse, G. Niehues, R. Ruprecht, T. Schmelzer, M. Schuh, M. Schwarz, M. Yan
KIT, Karlsruhe, Germany
T. Feurer, M. Hayati, Z. Ollmann, R. Tarkeshian
Universität Bern, Institute of Applied Physics, Bern, Switzerland

THz streaking with split ring resonators (SRR) promise ultra-high (sub-femtosecond) temporal resolution even for relativistic electron bunches. A proof-of-principle experiment in collaboration between the University of Bern, the Paul Scherrer Institute (PSI) and the Karlsruhe Institute of Technology (KIT) is currently prepared at the FLUTE facility (Ferninfrarot Linac und Test Experiment) at KIT. Most of the critical components have been designed, tested and set-up in the 7 MeV diagnostics part of FLUTE. In this contribution we will present an update on the experimental set-up and report on SRR configurations which have been optimized for highest THz deflection, while simultaneously accounting for the restrictions of the manufacturing process. Test measurements characterizing the SRR samples and the THz source, which has been matched to the FLUTE gun laser, will also be presented.

Poster TUPCC16 [0.539 MB]

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TUPCC17

Ultra-Stable Fiber-Optic Reference Distribution for SwissFEL C-Band Linacs Based on S-Band Radio-Over-Fiber Links and Frequency Doubler / Power Amplifiers

189

S. Hunziker, V.R. Arsov, F. Buechi, M. Dach, M. Heiniger, M.G. Kaiser, R. Kramert, A. Romann, V. Schlott
PSI, Villigen PSI, Switzerland

The reference distribution for the SwissFEL accelerator is based on ultra-stable Libera Sync 3 fiber-optic links operating at 3 GHz with <2.4fs added timing jitter. While s-band injector RF stations are directly supplied with these actively stabilized reference signals at 2.9988GHz, the same 3 GHz optical links are used to transmit reference signals at 2.856GHz (half c-band frequency) to the c-band LINACs, combined with a frequency doubler-amplifier at the link end. A novel zero AM/PM-conversion frequency-doubler and an amplitude-/phase-controlled power amplifier have been implemented in a compact 1HU 19inch unit. Key design concepts and measurement results will be presented. It will be shown that this inexpensive doubler-amplifier system adds only insignificant jitter and drift to the transmitted reference signals. As the same actively stabilized 3GHz links can be used for s- and c- band RF stations, development of a more expensive 6GHz fiber-optic link could be avoided. A higher quantity of the same link type can thus be manufactured and the number of spares is reduced as only one link type is utilized for the SwissFEL injector and LINAC RF reference signals.

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TUPCC18

Beam Arrival Time Measurement at SXFEL

193

S.S. Cao, J. Chen, Y.B. Leng
SINAP, Shanghai, People's Republic of China
R.X. Yuan
SSRF, Shanghai, People's Republic of China

Shanghai Soft X-ray Free Electron Laser (SXFEL) is a fourth-generation light source which could provide coherent X-rays for various scientific researches. One of the key issues of its operation is the measurement of bunch arrival time which is important for the synchronization of a bunch and seeded laser. The measurement utilized a newly designed beam arrival time monitor (BAM) which contains two cavities at a different frequency. Thus a new way, dual-cavities mixing method, is applied in this experiment to evaluate the beam arrival time resolution. In this paper, we presented the scheme and different measured resolution of various measurement methods and evaluated the stability of the new monitor.

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WE2AB1

Beam Diagnostics Overview and Challenges for Low-Energy, Low-Intensity Beams

C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Low-energetic ion and antimatter beams are very at-tractive for a number of fundamental studies. The diagnostics of such beams, however, is a challenge due to low currents down to only a few thousands of parti-cles per second and significant fraction of energy loss in matter at keV beam energies. On the example of the ELENA storage ring which is being commissioned at CERN this year, this paper summarizes the essential beam diagnostics required to fully characterize low energy, low intensity ion beams. THis includes beam-profile monitors based on scintillating screens and secondary electron emission, sensitive Faraday cups for absolute intensity measurements, and capacitive pickups for beam position monitoring as basic diagnostics. More advanced diagnostics options in-clude gas based beam profile monitors and ultra-sensitive beam current transformers using SQUID technology.

Slides WE2AB1 [4.519 MB]

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