IPAC2015 - List of Keywords (timing)

Paper	Title	Other Keywords	Page
MOPJE006	Electron Gun Longitudinal Jitter: Simulation and Analysis	gun, electron, linac, simulation	297
	M.S. Liu, Y.L. Chi, S. Pei, Y.F. Sui IHEP, Bejing, People's Republic of China
	The beam longitudinal jitter is fatal not only for the electron beam performance but also for the positron yield in routine operation of the Beijing Electron Positron Collider II (BEPCII) linear accelerator (Linac). Practically, longitudinal jitter has been observed many times which decreased the beam performance. We simulated the electron gun longitudinal jitter effect by PARMELA software in bunch capture process and analyzed its results about beam performance including average energy, energy spread, emittance and longitudinal phase of reference particle. We adjusted the electron gun trigger time during one cycle without changing other parameters. The percentage difference between maximum and minimum of average energy, energy spread, emittance and longitudinal phase of reference particle was 11.3%, 42%, 98% and 6.4%, respectively. It is observed and analyzed that gun trigger time longitudinal jitter is fatal for maintaining good beam performance. This analysis also gives a salutary lesson to any other longitudinal jitter which can affect the beam bunching in pre-injector .
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE006
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MOPMA007	Tracking Studies of a Higher-Harmonic Bunch-Lengthening Cavity for the Advanced Photon Source Upgrade	simulation, cavity, feedback, impedance	543
	M. Borland, T.G. Berenc, R.R. Lindberg, A. Xiao ANL, Argonne, Ilinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The Advanced Photon Source (APS) multi-bend achromat (MBA) lattice will require a bunch-lengthening cavity to decrease the effects of Touschek scattering on the beam lifetime and of intrabeam scattering on the beam emittance. Using ELEGANT, we've performed tracking studies of a passive, i.e. beam-driven, fourth-harmonic cavity in the MBA lattice, including the predicted longitudinal impedance of the ring. The studies include an exploration of the required detuning and loaded Q of the main rf cavities and the harmonic cavity in order to stabilize the beam and achieve significant lengthening. We also studied the effects of bunch population variation and missing bunches. The computed bunch profiles are used for computation of the Touschek lifetime, verifying the beneficial effects in detail.
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MOPHA012	A New FPGA Based Timing System at ELSA	FPGA, injection, booster, extraction	802
	D. Proft, W. Hillert ELSA, Bonn, Germany
	At the electron stretcher facility ELSA a beam intensity upgrade from 20 mA to 200 mA is in progress. Investigations showed, that the maximum beam current is currently limited by excitation of beam instabilities. For separated characterization of single bunch instabilities from multi-bunch ones, a high beam current stored in a single revolving bunch is required. These high beam currents can only be achieved by accumulation of many shots from the injector. The existing timing system is not capable of single bunch injection and accumulation in the main stretcher ring. Therefore a new FPGA based timing system, synchronized to the RF system of the accelerator, has been developed which will completely supersede the existing one. Simultaneously the ‘‘slow'' timing system, providing trigger signals for the typically 6 s long accelerator cycle, is also modernized using a similar FPGA based solution to achieve a much better duty cycle during standard operation. In this contribution the FPGA designs laying the focus on the single bunch accumulation will be presented.
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MOPHA026	Present and Future Optical-to-Microwave Synchronization Systems at REGAE Facility for Electron Diffraction and Plasma Acceleration Experiments	laser, electron, detector, plasma	833
	M. Titberidze, F.J. Grüner, A.R. Maier, B. Zeitler CFEL, Hamburg, Germany S.W. Epp MPSD, Hamburg, Germany M. Felber, K. Flöttmann, T. Lamb, U. Mavrič, J.M. Müller, H. Schlarb, C. Sydlo DESY, Hamburg, Germany F.J. Grüner, A.R. Maier, M. Titberidze Uni HH, Hamburg, Germany E. Janas Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
	Relativistic Electron Gun for Atomic Explorations (REGAE) is a Radio Frequency (RF) driven linear accelerator. It uses frequency tripled short photon pulses (~ 35 fs) from the Titanium Sapphire (Ti:Sa.) Laser system in order to generate electron bunches from the photo-cathode. The electron bunches are accelerated up to ~ 5 MeV kinetic energy and compressed down to sub-10 fs using the so called ballistic bunching technique. REGAE currently is used for electron diffraction experiments (by Prof. R.J.D. Miller's Group). In near future within the collaboration of Laboratory for Laser- and beam-driven plasma Acceleration (LAOLA), REGAE will also be employed to externally inject electron bunches into laser driven linear plasma waves. Both experiments require very precise synchronization (sub-50 fs) of the photo-injector laser and RF reference. In this paper we present experimental results of the current and new optical to microwave synchronization systems in comparison. We also address some of the issues related to the current system and give an upper limit in terms of its long-term performance.
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MOPHA032	All-Optical Synchronization of Pulsed Laser Systems at FLASH and XFEL	laser, LLRF, FEL, controls	854
	J.M. Müller, M.K. Czwalinna, M. Felber, M. Schäfer, H. Schlarb, B. Schmidt, S. Schulz, C. Sydlo, F. Zummack DESY, Hamburg, Germany
	The all-optical laser synchronization at FLASH and XFEL provides femtosecond-stable timing of the FEL X-ray photon pulses and associated optical laser pulses (photo-injector laser, seed laser, pump-probe laser, etc.). Based on a two-color balanced optical cross-correlation scheme a high-precision measure of the laser pulse arrival time is delivered, which is used for diagnostic purposes as well as for the active stabilization of the laser systems. In this paper, we present the latest installations of our all-optical synchronization systems at FLASH and the recent developments for the upcoming European XFEL that will ensure a reliable femtosecond-stable timing of FEL and related pulsed laser systems.
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MOPTY043	Update on the Development of the New Electronic Instrumentation for the LIPAc/IFMIF Beam Position Monitors	electronics, operation, EPICS, controls	1025
	A. Guirao, D. Jiménez-Rey, L.M. Martinez Fresno, E. Molina Marinas, J. Mollá, I. Podadera, I. Rivera CIEMAT, Madrid, Spain
	Funding: This work has been funded by the Spanish Ministry of Economy and Competitiveness under the project FIS2013-40860-R and the Agreement as published in BOE, 16/01/2013, page 1988 Among all the LIPAc/IFMIF accelerator diagnostics instrumentation, the Beam Position Monitors (BPMs) are a cornerstone for its operation. An electronics system centered on self-calibration and extraction of beam phase information for Time Of Flight measurement is proposed for the twenty BPM stations distributed along the accelerator. The system under development is a fully digital instrumentation which incorporates automatic calibration of the monitors' signals and allows monitoring of both fundamental and second signal harmonics. The current state of the development and first experimental results of the system on the test bench will be presented.
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TUPJE012	Preliminary Result of Photon Counting Acquisition Scheme for Laser Pump/X-ray Probe Experiments	laser, synchrotron, experiment, detector	1638
	J. He, J.S. Cao, G. Gao, Y.F. Sui, Y. Tao, J.H. Yue, Z. Zhang, Y.F. Zhou IHEP, Beijing, People's Republic of China
	Funding: This work is supported by the NSFC under grant No.11305186 R&D project has been initiated for a proposed ultralow emittance (~50pm.rad) synchrotron light source built in Beijing. The R&D includes the development of high repetition rate laser pump/X-ray probe for ultrafast dynamics detection in future source. In a typical laser pump/X-ray probe measurement, the X-ray pulse follows a laser pulse in adjustable delay. We are interested in the difference between laser on and laser off at different delay, which will snapshot dynamic process. To capture this trivial difference, it requires the acquisition system to single out the signal from this special X-ray pulse at adequate S/N ratio. For the R&D of high repetition rate pump-probe, we have set up a prototype counting acquisition system based on NIM modular electronics, which was tested in Beijing Synchrotron Radiation Facility (BSRF). The laser will be synchronized with a camshaft bunch at 124 kHz, a tenth of the revolution frequency. Avalanche Photo Diode (APD) was used to detect the X-ray pulse from this camshaft bunch due to its nanosecond response. Before the laser is delivered, we mimic the 124 kHz laser- on signal. The signals from APD are separated by power dividers into two Constant Fraction Discriminator (CFD) input channels. The signal in laser-on/off channel is gated out at 1.24MHz using the 1.24MHz timing signal divided from 499.8 MHz RF signal, while the mimic laser-on signal gated out at 124 kHz. Multiplied by ten times, the mimic laser-on signal counts should be consistent with the laser-on+off counts, if our counting modular works well. We carried out this test at 1W1B wiggler beam line to measure the Fe fluorescence signal. The performance of our system is demonstrated in the good consistency between mimic laser on and laser on+off signals.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE012
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TUPHA004	NSLS-II Storage Ring Injection Optimization	injection, kicker, betatron, septum	1968
	G.M. Wang, E.B. Blum, W.X. Cheng, J. Choi, Y. Li, S. Seletskiy, T.V. Shaftan, Y. Tian, L. Yang, L.-H. Yu BNL, Upton, Long Island, New York, USA
	The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source at Brookhaven National Laboratory. The SR is designed to work in top-off injection mode. The injection straight includes a septum and four fast kicker magnets with independent amplitude and timing control. The beam injection is designed as 9.5 mm off-axis in x plane and on-axis injection in y plane. To capture the injected beam within the SR acceptance for high injection efficiency, it requires 6-D phase space match. Besides that, the fast kickers formed local bump is also required to be locally to minimize the injected beam extra betatron oscillation and keep the stored beam disturbance within the specification, 10% beam size to minimize the injection transient. This paper will present the beam results before and after optimization.
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WEXB3	Realization of Pseudo Single Bunch Operation with Adjustable Frequency	kicker, experiment, operation, resonance	2396
	C. Sun, G.J. Portmann, D. Robin, C. Steier LBNL, Berkeley, California, USA
	Funding: This work is supported by the Director Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 We present the concept and results of pseudo-single-bunch (PSB) operation–a new operational mode at the advanced light source–that can greatly expand the capabilities of synchrotron light sources to carry out dynamics and time-of-flight experiments. In PSB operation, a single electron bunch is displaced transversely from the other electron bunches using a short-pulse, high-repetition-rate kicker magnet. Experiments that require light emitted only from a single bunch can stop the light emitted from the other bunches using a collimator. Other beam lines will only see a small reduction in flux due to the displaced bunch. As a result, PSB allows to run timing experiments during the multibunch operation. Furthermore, the time spacing of PSB pulses can be adjusted from milliseconds to microseconds with a novel “kick-and-cancel” scheme, which can significantly alleviate complications of using high-power choppers and substantially reduce the rate of sample damage.
	Slides WEXB3 [128.794 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEXB3
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WEPWA053	First Acceleration in a Resonant Optical-Scale Laser-Powered Structure	laser, acceleration, electron, alignment	2624
	R.B. Yoder Goucher College, Baltimore, Maryland, USA R.J. England, Z. Wu SLAC, Menlo Park, California, USA K.S. Hazra, B. Matthews, J.C. McNeur, E.B. Sozer, G. Travish UCLA, Los Angeles, USA E.A. Peralta, K. Soong Stanford University, Stanford, California, USA
	Funding: U.S. DTRA grant HDTRA1-09-1-0043 The Micro-Accelerator Platform (MAP), an optical-scale dielectric laser accelerator (DLA) based on a planar resonant structure that was developed at UCLA, has been tested experimentally. Successful acceleration was observed after a series of experimental runs at SLAC’s NLCTA facility, in which the input laser power was well below the predicted breakdown limit. Though acceleration gradients were modest (<50 MeV/m), these are the first proof-of-principle results for a resonant DLA structure. We present more detailed results and some implications for future work.
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WEPWA067	Acoustic Breakdown Localization in RF Cavities	cavity, simulation, experiment, diagnostics	2658
	P.G. Lane, P. Snopok, Y. Torun Illinois Institute of Technology, Chicago, Illinois, USA E. Behnke, I.Y. Levine Indiana University South Bend, South Bend, USA D.W. Peterson Fermilab, Batavia, Illinois, USA
	Funding: US Department of Energy Current designs for muon cooling channels require high-gradient RF cavities to be placed in solenoidal magnetic fields in order to contain muons with large transverse emittances. It has been found that doing so reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields it would be helpful to have a diagnostic tool which can detect breakdown and localize the source of the breakdown inside the cavity. We report here on acoustic simulations and comparisons with experimental acoustic data of breakdown from several RF cavities. Included in this analysis are our most recent results from attempting to localize breakdown using these data.
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WEPJE020	The Two Beam Acceleration Staging Experiment at Argonne Wakefield Accelerator Facility	acceleration, wakefield, experiment, kicker	2714
	C.-J. Jing, S.P. Antipov, A. Kanareykin, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, J.H. Shao, D. Wang, E.E. Wisniewski ANL, Argonne, Illinois, USA J. Shi TUB, Beijing, People's Republic of China
	Funding: DoE SBIR Program Staging, defined as the accelerated bunch in a wakefield accelerator continues to gain energy from sequential drive bunches, is one of the most critical technologies, yet be demonstrated, required to achieve high energy. Using the Two Beam Acceleration (TBA) beamline at Argonne Wakefield Accelerator facility, we will perform a staging experiment using two X-band TBA units. The experiment is planned to conduct in steps. We report on the most recent progress.
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WEPMA014	Development of New Microcontroller Based Power Supply Control Units at ELSA	controls, interface, power-supply, real-time	2777
	D. Proft, W. Hillert, T. Perlitius ELSA, Bonn, Germany
	At the electron stretcher facility ELSA electrons are accelerated with a high ramping speed of 6 GeV/s. This leads to strong requirements on the main magnets power supplies. In particular, any synchronization errors directly result in beam tune shifts and, at worst, beam loss. The existing thirty years old control units are now being replaced by new in-house developed versatile microcontroller based ones. These allow the application of arbitrary ramp patterns and actual value acquisition in realtime. With an ethernet interface the ramp patterns can be uploaded directly to the power supplies. The flexible design also allows usage of the module to control other power supplies, e.g. those of the orbit correction magnets. This presentation will give details on the developed hardware design and the performance of the modules compared to the existing ones.
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WEPMA024	System Design for a Deterministic Bunch-to-Bucket Transfer	synchrotron, simulation, LLRF, ion	2809
	T. Ferrand TEMF, TU Darmstadt, Darmstadt, Germany J.N. Bai IAP, Frankfurt am Main, Germany
	Funding: Supported by GSI and the Technical University Darmstadt in the frame of the cooperation for FAIR. A deterministic bunch to bucket transfer system is currently under development in the frame of the FAIR project at GSI. To achieve our accuracy and stability requirements, a set of hardware modules will be implemented. These hardware modules are expected to provide values such as the relative phase advance between the RF systems of both, the source and the target synchrotron according to an external timing system. These values are exchanged via optical fibers between different supply rooms, and the considered RF signals are re-synthesized locally. These re-synthesized signals are synchronized to enable a precise phase advance control between the synchrotrons’ RF systems. The first step of the development consists in modeling the actual DDS and DSP-based LLRF environment of the SIS18 under Ptolemy-II. Measurements on real devices will be performed concurrently to the simulation. We expect to use this simulation to refine our timing expectations regarding the synchronization process and the inter-module communication protocols and design the synchronization function, which will be implemented on the hardware modules.
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WEPMA058	New Injection Bump Power Supply of the J-PARC RCS*	power-supply, injection, operation, flattop	2908
	T. Takayanagi, N. Hayashi, K. Horino, M. Kinsho, K. Okabe, T. Ueno JAEA/J-PARC, Tokai-mura, Japan Y. Irie KEK, Ibaraki, Japan
	The new horizontal shift bump (SB) power supply for beam injection system of the J-PARC (Japan Proton Accelerator Research Complex) 3-GeV RCS (Rapid-Cycling Synchrotron) has been developed and manufactured. The injection energy was increased from 181 MeV to 400 MeV, and the power capacity of the new power supply was doubled. The power supply newly adopted a capacitor commutation method to form the trapezoid waveform pattern (bump waveform) by the IGBT (Insulated Gate Bipolar Transistor) switch. This paper reports characteristic, the problems and the user operation status about the new shift bump power supply.
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WEPMN061	ESS PLC Controls Strategy	PLC, controls, hardware, vacuum	3066
	D.P. Piso, P. Arnold, S.L. Birch, T. Gahl, T. Korhonen, A. Nordt, J.G. Weisend ESS, Lund, Sweden
	The European Spallation Source ESS AB is an accelerator-driven neutron spallation source. The Integrated Controls System (ICS) division is responsible for providing controls and monitoring for all parts of the machine (accelerator, target, neutron scattering systems and conventional facilities). Also, Accelerator Division, Target Division and other parts of the organisation will be deploying PLC Automation Systems. A large number of applications have been identified across all the facility where PLCs will be used: cryogenics, vacuum, water-cooling, fluid systems, power systems, and safety \& protection systems. This work describes the different activities put in place and proposes the strategy followed at ESS regarding PLC technologies. This strategy consists not only of the standardisation of a PLC vendor but also testing activities, generation of documentation and standardization of other aspects (for instance, regarding installation). The documentation about PLC controls integration and standardisation and the approach to insert PLCs in the different controls workflows are described. Finally, the results of different tests (PLC timing correlation) are shown.
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Paper

Title

Other Keywords

Page

MOPJE006

Electron Gun Longitudinal Jitter: Simulation and Analysis

gun, electron, linac, simulation

297

M.S. Liu, Y.L. Chi, S. Pei, Y.F. Sui
IHEP, Bejing, People's Republic of China

The beam longitudinal jitter is fatal not only for the electron beam performance but also for the positron yield in routine operation of the Beijing Electron Positron Collider II (BEPCII) linear accelerator (Linac). Practically, longitudinal jitter has been observed many times which decreased the beam performance. We simulated the electron gun longitudinal jitter effect by PARMELA software in bunch capture process and analyzed its results about beam performance including average energy, energy spread, emittance and longitudinal phase of reference particle. We adjusted the electron gun trigger time during one cycle without changing other parameters. The percentage difference between maximum and minimum of average energy, energy spread, emittance and longitudinal phase of reference particle was 11.3%, 42%, 98% and 6.4%, respectively. It is observed and analyzed that gun trigger time longitudinal jitter is fatal for maintaining good beam performance. This analysis also gives a salutary lesson to any other longitudinal jitter which can affect the beam bunching in pre-injector .

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MOPMA007

Tracking Studies of a Higher-Harmonic Bunch-Lengthening Cavity for the Advanced Photon Source Upgrade

simulation, cavity, feedback, impedance

543

M. Borland, T.G. Berenc, R.R. Lindberg, A. Xiao
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS) multi-bend achromat (MBA) lattice will require a bunch-lengthening cavity to decrease the effects of Touschek scattering on the beam lifetime and of intrabeam scattering on the beam emittance. Using ELEGANT, we've performed tracking studies of a passive, i.e. beam-driven, fourth-harmonic cavity in the MBA lattice, including the predicted longitudinal impedance of the ring. The studies include an exploration of the required detuning and loaded Q of the main rf cavities and the harmonic cavity in order to stabilize the beam and achieve significant lengthening. We also studied the effects of bunch population variation and missing bunches. The computed bunch profiles are used for computation of the Touschek lifetime, verifying the beneficial effects in detail.

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MOPHA012

A New FPGA Based Timing System at ELSA

FPGA, injection, booster, extraction

802

D. Proft, W. Hillert
ELSA, Bonn, Germany

At the electron stretcher facility ELSA a beam intensity upgrade from 20 mA to 200 mA is in progress. Investigations showed, that the maximum beam current is currently limited by excitation of beam instabilities. For separated characterization of single bunch instabilities from multi-bunch ones, a high beam current stored in a single revolving bunch is required. These high beam currents can only be achieved by accumulation of many shots from the injector. The existing timing system is not capable of single bunch injection and accumulation in the main stretcher ring. Therefore a new FPGA based timing system, synchronized to the RF system of the accelerator, has been developed which will completely supersede the existing one. Simultaneously the ‘‘slow'' timing system, providing trigger signals for the typically 6 s long accelerator cycle, is also modernized using a similar FPGA based solution to achieve a much better duty cycle during standard operation. In this contribution the FPGA designs laying the focus on the single bunch accumulation will be presented.

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MOPHA026

Present and Future Optical-to-Microwave Synchronization Systems at REGAE Facility for Electron Diffraction and Plasma Acceleration Experiments

laser, electron, detector, plasma

833

M. Titberidze, F.J. Grüner, A.R. Maier, B. Zeitler
CFEL, Hamburg, Germany
S.W. Epp
MPSD, Hamburg, Germany
M. Felber, K. Flöttmann, T. Lamb, U. Mavrič, J.M. Müller, H. Schlarb, C. Sydlo
DESY, Hamburg, Germany
F.J. Grüner, A.R. Maier, M. Titberidze
Uni HH, Hamburg, Germany
E. Janas
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

Relativistic Electron Gun for Atomic Explorations (REGAE) is a Radio Frequency (RF) driven linear accelerator. It uses frequency tripled short photon pulses (~ 35 fs) from the Titanium Sapphire (Ti:Sa.) Laser system in order to generate electron bunches from the photo-cathode. The electron bunches are accelerated up to ~ 5 MeV kinetic energy and compressed down to sub-10 fs using the so called ballistic bunching technique. REGAE currently is used for electron diffraction experiments (by Prof. R.J.D. Miller's Group). In near future within the collaboration of Laboratory for Laser- and beam-driven plasma Acceleration (LAOLA), REGAE will also be employed to externally inject electron bunches into laser driven linear plasma waves. Both experiments require very precise synchronization (sub-50 fs) of the photo-injector laser and RF reference. In this paper we present experimental results of the current and new optical to microwave synchronization systems in comparison. We also address some of the issues related to the current system and give an upper limit in terms of its long-term performance.

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MOPHA032

All-Optical Synchronization of Pulsed Laser Systems at FLASH and XFEL

laser, LLRF, FEL, controls

854

J.M. Müller, M.K. Czwalinna, M. Felber, M. Schäfer, H. Schlarb, B. Schmidt, S. Schulz, C. Sydlo, F. Zummack
DESY, Hamburg, Germany

The all-optical laser synchronization at FLASH and XFEL provides femtosecond-stable timing of the FEL X-ray photon pulses and associated optical laser pulses (photo-injector laser, seed laser, pump-probe laser, etc.). Based on a two-color balanced optical cross-correlation scheme a high-precision measure of the laser pulse arrival time is delivered, which is used for diagnostic purposes as well as for the active stabilization of the laser systems. In this paper, we present the latest installations of our all-optical synchronization systems at FLASH and the recent developments for the upcoming European XFEL that will ensure a reliable femtosecond-stable timing of FEL and related pulsed laser systems.

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MOPTY043

Update on the Development of the New Electronic Instrumentation for the LIPAc/IFMIF Beam Position Monitors

electronics, operation, EPICS, controls

1025

A. Guirao, D. Jiménez-Rey, L.M. Martinez Fresno, E. Molina Marinas, J. Mollá, I. Podadera, I. Rivera
CIEMAT, Madrid, Spain

Funding: This work has been funded by the Spanish Ministry of Economy and Competitiveness under the project FIS2013-40860-R and the Agreement as published in BOE, 16/01/2013, page 1988
Among all the LIPAc/IFMIF accelerator diagnostics instrumentation, the Beam Position Monitors (BPMs) are a cornerstone for its operation. An electronics system centered on self-calibration and extraction of beam phase information for Time Of Flight measurement is proposed for the twenty BPM stations distributed along the accelerator. The system under development is a fully digital instrumentation which incorporates automatic calibration of the monitors' signals and allows monitoring of both fundamental and second signal harmonics. The current state of the development and first experimental results of the system on the test bench will be presented.

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TUPJE012

Preliminary Result of Photon Counting Acquisition Scheme for Laser Pump/X-ray Probe Experiments

laser, synchrotron, experiment, detector

1638

J. He, J.S. Cao, G. Gao, Y.F. Sui, Y. Tao, J.H. Yue, Z. Zhang, Y.F. Zhou
IHEP, Beijing, People's Republic of China

Funding: This work is supported by the NSFC under grant No.11305186
R&D project has been initiated for a proposed ultralow emittance (~50pm.rad) synchrotron light source built in Beijing. The R&D includes the development of high repetition rate laser pump/X-ray probe for ultrafast dynamics detection in future source. In a typical laser pump/X-ray probe measurement, the X-ray pulse follows a laser pulse in adjustable delay. We are interested in the difference between laser on and laser off at different delay, which will snapshot dynamic process. To capture this trivial difference, it requires the acquisition system to single out the signal from this special X-ray pulse at adequate S/N ratio. For the R&D of high repetition rate pump-probe, we have set up a prototype counting acquisition system based on NIM modular electronics, which was tested in Beijing Synchrotron Radiation Facility (BSRF). The laser will be synchronized with a camshaft bunch at 124 kHz, a tenth of the revolution frequency. Avalanche Photo Diode (APD) was used to detect the X-ray pulse from this camshaft bunch due to its nanosecond response. Before the laser is delivered, we mimic the 124 kHz laser- on signal. The signals from APD are separated by power dividers into two Constant Fraction Discriminator (CFD) input channels. The signal in laser-on/off channel is gated out at 1.24MHz using the 1.24MHz timing signal divided from 499.8 MHz RF signal, while the mimic laser-on signal gated out at 124 kHz. Multiplied by ten times, the mimic laser-on signal counts should be consistent with the laser-on+off counts, if our counting modular works well. We carried out this test at 1W1B wiggler beam line to measure the Fe fluorescence signal. The performance of our system is demonstrated in the good consistency between mimic laser on and laser on+off signals.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE012

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TUPHA004

NSLS-II Storage Ring Injection Optimization

injection, kicker, betatron, septum

1968

G.M. Wang, E.B. Blum, W.X. Cheng, J. Choi, Y. Li, S. Seletskiy, T.V. Shaftan, Y. Tian, L. Yang, L.-H. Yu
BNL, Upton, Long Island, New York, USA

The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source at Brookhaven National Laboratory. The SR is designed to work in top-off injection mode. The injection straight includes a septum and four fast kicker magnets with independent amplitude and timing control. The beam injection is designed as 9.5 mm off-axis in x plane and on-axis injection in y plane. To capture the injected beam within the SR acceptance for high injection efficiency, it requires 6-D phase space match. Besides that, the fast kickers formed local bump is also required to be locally to minimize the injected beam extra betatron oscillation and keep the stored beam disturbance within the specification, 10% beam size to minimize the injection transient. This paper will present the beam results before and after optimization.

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WEXB3

Realization of Pseudo Single Bunch Operation with Adjustable Frequency

kicker, experiment, operation, resonance

2396

C. Sun, G.J. Portmann, D. Robin, C. Steier
LBNL, Berkeley, California, USA

Funding: This work is supported by the Director Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
We present the concept and results of pseudo-single-bunch (PSB) operation–a new operational mode at the advanced light source–that can greatly expand the capabilities of synchrotron light sources to carry out dynamics and time-of-flight experiments. In PSB operation, a single electron bunch is displaced transversely from the other electron bunches using a short-pulse, high-repetition-rate kicker magnet. Experiments that require light emitted only from a single bunch can stop the light emitted from the other bunches using a collimator. Other beam lines will only see a small reduction in flux due to the displaced bunch. As a result, PSB allows to run timing experiments during the multibunch operation. Furthermore, the time spacing of PSB pulses can be adjusted from milliseconds to microseconds with a novel “kick-and-cancel” scheme, which can significantly alleviate complications of using high-power choppers and substantially reduce the rate of sample damage.

Slides WEXB3 [128.794 MB]

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WEPWA053

First Acceleration in a Resonant Optical-Scale Laser-Powered Structure

laser, acceleration, electron, alignment

2624

R.B. Yoder
Goucher College, Baltimore, Maryland, USA
R.J. England, Z. Wu
SLAC, Menlo Park, California, USA
K.S. Hazra, B. Matthews, J.C. McNeur, E.B. Sozer, G. Travish
UCLA, Los Angeles, USA
E.A. Peralta, K. Soong
Stanford University, Stanford, California, USA

Funding: U.S. DTRA grant HDTRA1-09-1-0043
The Micro-Accelerator Platform (MAP), an optical-scale dielectric laser accelerator (DLA) based on a planar resonant structure that was developed at UCLA, has been tested experimentally. Successful acceleration was observed after a series of experimental runs at SLAC’s NLCTA facility, in which the input laser power was well below the predicted breakdown limit. Though acceleration gradients were modest (<50 MeV/m), these are the first proof-of-principle results for a resonant DLA structure. We present more detailed results and some implications for future work.

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WEPWA067

Acoustic Breakdown Localization in RF Cavities

cavity, simulation, experiment, diagnostics

2658

P.G. Lane, P. Snopok, Y. Torun
Illinois Institute of Technology, Chicago, Illinois, USA
E. Behnke, I.Y. Levine
Indiana University South Bend, South Bend, USA
D.W. Peterson
Fermilab, Batavia, Illinois, USA

Funding: US Department of Energy
Current designs for muon cooling channels require high-gradient RF cavities to be placed in solenoidal magnetic fields in order to contain muons with large transverse emittances. It has been found that doing so reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields it would be helpful to have a diagnostic tool which can detect breakdown and localize the source of the breakdown inside the cavity. We report here on acoustic simulations and comparisons with experimental acoustic data of breakdown from several RF cavities. Included in this analysis are our most recent results from attempting to localize breakdown using these data.

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WEPJE020

The Two Beam Acceleration Staging Experiment at Argonne Wakefield Accelerator Facility

acceleration, wakefield, experiment, kicker

2714

C.-J. Jing, S.P. Antipov, A. Kanareykin, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, J.H. Shao, D. Wang, E.E. Wisniewski
ANL, Argonne, Illinois, USA
J. Shi
TUB, Beijing, People's Republic of China

Funding: DoE SBIR Program
Staging, defined as the accelerated bunch in a wakefield accelerator continues to gain energy from sequential drive bunches, is one of the most critical technologies, yet be demonstrated, required to achieve high energy. Using the Two Beam Acceleration (TBA) beamline at Argonne Wakefield Accelerator facility, we will perform a staging experiment using two X-band TBA units. The experiment is planned to conduct in steps. We report on the most recent progress.

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WEPMA014

Development of New Microcontroller Based Power Supply Control Units at ELSA

controls, interface, power-supply, real-time

2777

D. Proft, W. Hillert, T. Perlitius
ELSA, Bonn, Germany

At the electron stretcher facility ELSA electrons are accelerated with a high ramping speed of 6 GeV/s. This leads to strong requirements on the main magnets power supplies. In particular, any synchronization errors directly result in beam tune shifts and, at worst, beam loss. The existing thirty years old control units are now being replaced by new in-house developed versatile microcontroller based ones. These allow the application of arbitrary ramp patterns and actual value acquisition in realtime. With an ethernet interface the ramp patterns can be uploaded directly to the power supplies. The flexible design also allows usage of the module to control other power supplies, e.g. those of the orbit correction magnets. This presentation will give details on the developed hardware design and the performance of the modules compared to the existing ones.

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WEPMA024

System Design for a Deterministic Bunch-to-Bucket Transfer

synchrotron, simulation, LLRF, ion

2809

T. Ferrand
TEMF, TU Darmstadt, Darmstadt, Germany
J.N. Bai
IAP, Frankfurt am Main, Germany

Funding: Supported by GSI and the Technical University Darmstadt in the frame of the cooperation for FAIR.
A deterministic bunch to bucket transfer system is currently under development in the frame of the FAIR project at GSI. To achieve our accuracy and stability requirements, a set of hardware modules will be implemented. These hardware modules are expected to provide values such as the relative phase advance between the RF systems of both, the source and the target synchrotron according to an external timing system. These values are exchanged via optical fibers between different supply rooms, and the considered RF signals are re-synthesized locally. These re-synthesized signals are synchronized to enable a precise phase advance control between the synchrotrons’ RF systems. The first step of the development consists in modeling the actual DDS and DSP-based LLRF environment of the SIS18 under Ptolemy-II. Measurements on real devices will be performed concurrently to the simulation. We expect to use this simulation to refine our timing expectations regarding the synchronization process and the inter-module communication protocols and design the synchronization function, which will be implemented on the hardware modules.

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WEPMA058

New Injection Bump Power Supply of the J-PARC RCS*

power-supply, injection, operation, flattop

2908

T. Takayanagi, N. Hayashi, K. Horino, M. Kinsho, K. Okabe, T. Ueno
JAEA/J-PARC, Tokai-mura, Japan
Y. Irie
KEK, Ibaraki, Japan

The new horizontal shift bump (SB) power supply for beam injection system of the J-PARC (Japan Proton Accelerator Research Complex) 3-GeV RCS (Rapid-Cycling Synchrotron) has been developed and manufactured. The injection energy was increased from 181 MeV to 400 MeV, and the power capacity of the new power supply was doubled. The power supply newly adopted a capacitor commutation method to form the trapezoid waveform pattern (bump waveform) by the IGBT (Insulated Gate Bipolar Transistor) switch. This paper reports characteristic, the problems and the user operation status about the new shift bump power supply.

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WEPMN061

ESS PLC Controls Strategy

PLC, controls, hardware, vacuum

3066

D.P. Piso, P. Arnold, S.L. Birch, T. Gahl, T. Korhonen, A. Nordt, J.G. Weisend
ESS, Lund, Sweden

The European Spallation Source ESS AB is an accelerator-driven neutron spallation source. The Integrated Controls System (ICS) division is responsible for providing controls and monitoring for all parts of the machine (accelerator, target, neutron scattering systems and conventional facilities). Also, Accelerator Division, Target Division and other parts of the organisation will be deploying PLC Automation Systems. A large number of applications have been identified across all the facility where PLCs will be used: cryogenics, vacuum, water-cooling, fluid systems, power systems, and safety \& protection systems. This work describes the different activities put in place and proposes the strategy followed at ESS regarding PLC technologies. This strategy consists not only of the standardisation of a PLC vendor but also testing activities, generation of documentation and standardization of other aspects (for instance, regarding installation). The documentation about PLC controls integration and standardisation and the approach to insert PLCs in the different controls workflows are described. Finally, the results of different tests (PLC timing correlation) are shown.

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