IPAC2021 - List of Keywords (timing)

Paper	Title	Other Keywords	Page
MOPAB124	APS Booster Injection Horizontal Trajectory Control Upgrade	injection, controls, booster, operation	449
	C. Yao, J.R. Calvey, G.I. Fystro, A.F. Pietryla, H. Shang ANL, Lemont, Illinois, USA
	Funding: * Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-ACO₂-O6CH11357. The APS booster is a 7-GeV electron synchrotron with a 0.5-second cycle. The booster runs a set of injection control programs that correct the beam trajectory in the horizontal and longitudinal planes, and the betatron tunes. Recently we developed a single-turn BPM controllaw program for horizontal trajectory control to replace the previous FFT based horizontal controllaw program. We present the system configuration and results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB124
About •	paper received ※ 15 May 2021 paper accepted ※ 27 May 2021 issue date ※ 21 August 2021
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MOPAB154	Multi-Cell Accelerating Structure Driven by a Lens-Focused Picosecond THz Pulse	laser, focusing, electron, acceleration	537
	S.P. Antipov, S.V. Kuzikov Euclid TechLabs, Solon, Ohio, USA A.A. Vikharev IAP/RAS, Nizhny Novgorod, Russia
	Recently, gradients on the order of 1 GV/m level have been obtained in a form of a single cycle (~1 ps) THz pulses produced by conversion of a high peak power laser radiation in nonlinear crystals (~1 mJ, 1 ps, up to 3% conversion efficiency). Such high-intensity radiation can be utilized for charged particle acceleration. However, these pulses are short in time (~1ps) and broadband, therefore a new accelerating structure type is required. In this paper, we propose a novel structure based on focusing of THz radiation in accelerating cell and stacking such cells to achieve a long-range interaction required for an efficient acceleration process. We present an example in which a 100 microJoule THz pulse produces a 600 keV energy gain in 5 mm long 10 cell accelerating structure for an ultra-relativistic electron. This design can be readily extended to non-relativistic particles. Such structure had been laser microfabricated and appropriate dimensions were achieved.
	Poster MOPAB154 [1.283 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB154
About •	paper received ※ 27 May 2021 paper accepted ※ 05 July 2021 issue date ※ 14 August 2021
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TUPAB078	Relative Timing Jitter Effects on Two-stage Seeded FEL at SHINE	FEL, laser, electron, radiation	1551
	H.X. Yang SINAP, Shanghai, People’s Republic of China H.X. Deng, B. Liu, D. Wang, K.S. Zhou SARI-CAS, Pudong, Shanghai, People’s Republic of China
	Funding: The National Key Research and Development Program of China (Grants No. 2016YFA0401901, No. 2018YFE0103100) and the National Natural Science Foundation of China (Grants No. 11935020, No. 11775293). The synchronization between the ultrashort electron beam and external seed laser is essential for seeded FELs, especially for a multi-stage one. In this paper, we demonstrate a simple method to obtain the correlations between the pulse energy and relative timing jitter for evaluating the corresponding effects. In this method, the sensitivity of the output FEL performance against electron beam properties is demonstrated by scanning the electron beam and seed lasers, and the fitted curve is used to predict the pulse energy in different timing jitter by random sampling. The results indicate that the pulse energy of the first-stage EEHG is more stable than the second-stage HGHG. Meanwhile, the rise of bunch charge from 100 pC to 300 pC can reduce the timing control requirement by a factor of least 3 for the RMS timing jitter in our numerical simulations based on the parameters of Shanghai High-Repetition-Rate XFEL and Extreme Light Facility. The timing jitter study can demonstrate the feasibility of the EEHG-HGHG cascading scheme in different current profiles for generating Fourier-transform-limited soft X-ray FEL.
	Poster TUPAB078 [0.866 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB078
About •	paper received ※ 11 May 2021 paper accepted ※ 11 June 2021 issue date ※ 21 August 2021
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TUPAB181	Demonstration of Electron Cooling using a Pulsed Beam from an Electrostatic Electron Cooler	electron, experiment, space-charge, emittance	1827
	M.W. Bruker, S.V. Benson, A. Hutton, K. Jordan, T. Powers, R.A. Rimmer, T. Satogata, A.V. Sy, H. Wang, S. Wang, H. Zhang, Y. Zhang JLab, Newport News, Virginia, USA J. Li, F. Ma, X.M. Ma, L.J. Mao, X.P. Sha, M.T. Tang, J.C. Yang, X.D. Yang, H.W. Zhao IMP/CAS, Lanzhou, People’s Republic of China H. Zhao BNL, Upton, New York, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. Electron cooling continues to be an invaluable technique to reduce and maintain the emittance in hadron storage rings in cases where stochastic cooling is inefficient and radiative cooling is negligible. Extending the energy range of electron coolers beyond what is feasible with the conventional, electrostatic approach necessitates the use of RF fields for acceleration and, thus, a bunched electron beam. To experimentally investigate how the relative time structure of the two beams affects the cooling properties, we have set up a pulsed-beam cooling device by adding a synchronized pulsing circuit to the conventional electron source of the CSRm cooler at Institute of Modern Physics . We show the effect of the electron bunch length and longitudinal ion focusing strength on the temporal evolution of the longitudinal and transverse ion beam profile and demonstrate the detrimental effect of timing jitter as predicted by theory and simulations. Compared to actual RF-based coolers, the simplicity and flexibility of our setup will facilitate further investigations of specific aspects of bunched cooling such as synchro-betatron coupling and phase dithering. M. W. Bruker et al., Phys. Rev. Accel. Beams 24, 012801 (2021)
	Poster TUPAB181 [3.699 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB181
About •	paper received ※ 19 May 2021 paper accepted ※ 15 June 2021 issue date ※ 21 August 2021
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TUPAB319	SNS Credited Beam Power Limit System Preliminary Design	PLC, target, controls, dipole	2242
	C. Deibele ORNL, Oak Ridge, Tennessee, USA K.L. Mahoney ORNL RAD, Oak Ridge, Tennessee, USA
	The Controls Group at the Spallation Neutron Source (SNS) is designing a programmable signal processor based credited safety control that calculates pulsed beam power based on beam kinetic energy and charge. The system must reliably shut off the beam if the average power exceeds 2.145 MW averaged over 60 seconds. This paper discusses architecture and design choices needed to develop the system under the auspices of a programmable radiation-safety credit control.
	Poster TUPAB319 [1.925 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB319
About •	paper received ※ 16 May 2021 paper accepted ※ 02 July 2021 issue date ※ 25 August 2021
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WEPAB052	Development of an EO Sampling System for the Analysis of THz Waves Generated by Coherent Cherenkov Radiation	radiation, electron, laser, experiment	2718
	K. Murakoshi, Y. Koshiba, T. Murakami, K. Sakaue, Y. Tadenuma, P. Wang, M. Washio Waseda University, Tokyo, Japan R. Kuroda AIST, Tsukuba, Japan K. Sakaue The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan
	THz waves, located between microwaves and light waves, have transparency, directionality and fingerprint spectrum of specific materials. Therefore, they are expected to be useful for various applications. We have been studying THz waves generation via Cherenkov radiation with electron beams from a photocathode rf-gun. In our early studies, we have succeeded in the generation of coherent Cherenkov radiation by tilted electron beams using an rf-deflector. Furthermore, we have generated quasi-monochromatic THz waves by spatially modulated electron beams and have succeeded in its measurement by bandpass filters. This study aims to obtain the THz wave form in time domain by electro-optic (EO) sampling, which is an useful detection system for obtaining the information of the electric field and the phase simultaneously with high S/N. In this conference, we report about our probe laser system, results of the time-domain spectroscopy measurement of THz waves by EO sampling, and future prospects.
	Poster WEPAB052 [0.861 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB052
About •	paper received ※ 19 May 2021 paper accepted ※ 07 June 2021 issue date ※ 31 August 2021
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WEPAB282	The Consolidation of the CERN Beam Interlock System	operation, diagnostics, controls, interface	3309
	R.L. Johnson, C. Martin, T. Podzorny, I. Romera, R. Secondo, J.A. Uythoven CERN, Geneva, Switzerland
	The Beam Interlock System (BIS) is a machine protection system that provides essential interlock control throughout the CERN accelerator complex. The current BIS has been in service since 2006; as such, it is approaching the end of its operational lifetime, with most components being obsolete. A second version of the Beam Interlock System, "BIS2", is currently under development and will replace the current system. BIS2 aims to be more flexible by supplying additional on-board diagnostic tools, while also improving the overall safety by adding more redundancy. Crucially, BIS2 increases the number of critical paths that can be interlocked by almost 50%, providing an important flexibility for future additional interlocking requests. BIS2 will come into operation for the LHC in run 4 (2027) and will remain in operation until the end of the planned lifetime of HL-LHC. In this paper, we will focus on the Beam Interlock Controller Manager board (CIBM), which is at the heart of BIS2. Since this module works closely with many other systems that are similar in design to those in BIS1, we will compare how BIS2 improves upon BIS1, and justify the reasons why these changes were made.
	Poster WEPAB282 [0.378 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB282
About •	paper received ※ 18 May 2021 paper accepted ※ 14 July 2021 issue date ※ 23 August 2021
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WEPAB285	High Resolution Arrival Time Measurement of the Seed Laser	laser, FEL, electron, experiment	3320
	J.G. Wang, H.X. Deng, L. Feng, C.L. Li, B. Liu SARI-CAS, Pudong, Shanghai, People’s Republic of China X.T. Wang, W.Y. Zhang Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China
	The Shanghai soft X-ray Free-Electron Laser facility (SXFEL) is a fourth-generation linac-based light source, capable of producing X-ray pulses with a duration of tens of femtosecond. The seed laser for external seeding FEL, therefore, has tight requirements for relative arrival time to the electron bunch. To reach the required energy and wavelength for external seeding FEL, further optical amplification and frequency conversion is needed. These include reflection and propagation in different material and in air, in addition, also include the long laser transport beamline to the undulator, make the laser pulses arrival time influenced by environmental variation. To reach the required specification, high-resolution measurement of the laser arrival time is necessary. In this paper, we present a general concept for the measurement of the laser arrival time.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB285
About •	paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 12 August 2021
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WEPAB286	Design of the Laser-to-RF Synchronization at 1.3 GHz for SHINE	electron, laser, electronics, FEM	3323
	J.G. Wang, H.X. Deng, L. Feng, C.L. Li, B. Liu SARI-CAS, Pudong, Shanghai, People’s Republic of China X.T. Wang, W.Y. Zhang Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China
	A next-generation photo-science facility like Shanghai HIgh repetition rate XFEL aNd Extreme light facility (SHINE) is aiming to generate femtosecond X-ray pulses with unprecedented brightness to film chemical and physical reactions with sub-atomic level spatio-temporal resolution. To fulfill this scientific goal, high-precision timing synchronization is essential. The pulsed optical synchronization has become an indispensable scheme for femtosecond precision synchronization of X-ray free-electron lasers. One of the critical tasks of pulsed optical synchronization is to synchronize various microwave sources. For the future SHINE, ultralow-noise pulses generated by a mode-locked laser are distributed over large distances via stabilized fiber links to all critical facility end-stations. In order to achieve low timing jitter and long-term stability of 1.3 GHz RF reference signal for the accuracy Low-Level RF(RF) field control, an Electro-optical intensity Modulator (EOM) based scheme is being developed at SHINE. In this paper, we present the progress on the design of the optical part and the integrated electronics of the laser-to-RF synchronization.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB286
About •	paper received ※ 20 May 2021 paper accepted ※ 12 July 2021 issue date ※ 28 August 2021
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WEPAB287	Upgrade of the ELBE Timing System	operation, gun, hardware, GUI	3326
	M. Kuntzsch, M. Justus, A. Schwarz, K. Zenker HZDR, Dresden, Germany L. Krmpotic, U. Legat, U. Rojec Cosylab, Ljubljana, Slovenia Ž. Oven COSYLAB, Control System Laboratory, Ljubljana, Slovenia
	At the ELBE accelerator center a superconducting linac is operated to drive manifold secondary radiation sources like two infrared FELs, a positron source and a THz facility. The machine uses two injectors as electron sources that are accelerated in the main linac. The user experiments demand a large variety of bunch patterns from single shot to macro pulsed and cw beam at up to 26 MHz repetition rate. At ELBE a new timing system is being developed based on the MRF hardware platform and the MRF Timing System IOC. It uses two masters and a scalable number of connected receivers to generate the desired pulse patterns for operating the machine and to control user experiments. The contribution will show the architecture of the timing system, the control interfacing and performance measurements acquired on the test bench.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB287
About •	paper received ※ 21 May 2021 paper accepted ※ 01 July 2021 issue date ※ 13 August 2021
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WEPAB288	A New Timing System for PETRA IV	controls, FEL, storage-ring, hardware	3329
	H. Lippek, A. Aghababyan, K. Brede, H.T. Duhme, M. Fenner, U. Hurdelbrink, H. Kay, H. Schlarb, T. Wilksen DESY, Hamburg, Germany
	At DESY an upgrade of the PETRA III synchrotron light source towards a fourth-generation, low emittance machine PETRA IV is currently being actively pursued. The realization of this new machine implies a new design of the timing and synchronization system since requirements on beam quality and controls will significantly change from the existing implementation at PETRA III. As of now the technical design phase of the PETRA IV project is in full swing. For the timing system the design process of the overall system as well as the evaluation of individual components has been started as of last year. Given the success of the at DESY developed MicroTCA.4-based timing system for the European XFEL accelerator it has been chosen to serve as a basis for the PETRA IV timing system developement as well. We present first design ideas of the major timing system hardware component, a MicroTCA.4-based AMC for distributing clocks, triggers and further bunch-synchronous information within the accelerator complex and to user experiments. First steps of an evaluation process for designing the AMC hardware are briefly illustrated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB288
About •	paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 10 August 2021
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WEPAB321	ALS-U Instrumentation Overview	instrumentation, electron, controls, hardware	3427
	J.M. Weber, J.C. Bell, M.J. Chin, S. De Santis, R.F. Gunion, S. Murthy, W.E. Norum, G.J. Portmann, C. Serrano LBNL, Berkeley, California, USA W.K. Lewis Osprey DCS LLC, Ocean City, USA
	Funding: Work supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 The Advanced Light Source Upgrade (ALS-U) to a diffraction-limited storage ring with a small vacuum chamber diameter requires excellent orbit stability and a fast response orbit interlock for machine protection. The on-axis swap-out injection scheme and dual RF frequencies demand fast monitoring of pulsed injection magnets and a novel approach to timing. Recent development efforts at ALS and advances in PLLs, FPGAs, and RFSoCs that provide higher performance and mixed-signal integration can be leveraged for instrumentation solutions to these accelerator challenges. An overview of preliminary ALS-U instrumentation system designs and status will be presented.
	Poster WEPAB321 [23.306 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB321
About •	paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 22 August 2021
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WEPAB351	Requirements for an Inductive Voltage Adder as Driver for a Kicker Magnet with Short Circuit Termination	kicker, impedance, simulation, flattop	3521
	J. Ruf, M.J. Barnes, T. Kramer CERN, Geneva 23, Switzerland M. Sack KIT, Karlsruhe, Germany
	At CERN pulse generators based on Thyratron switches and SF6 gas filled pulse forming lines, used for driving kicker magnets, are to be replaced with semiconductor technology. Preliminary investigations show the inductive voltage adder is suitable as a pulse generator for this application. To increase the magnetic field without raising the system voltage, a short-circuit termination is often applied to a kicker magnet. Because of the electrical length of a transmission line magnet, wave propagation needs to be considered. To allow for the wavefront reflected from the short-circuit termination back to the generator, a novel approach for an inductive adder architecture has been investigated. It is based on a modified generator interface, circulating the current back into the load, until the stored energy is absorbed at the end of the pulse. This approach allows for a smaller magnetic core size compared to a conventional design with a matched load. Moreover, it enables more energy-efficient operation involving smaller storage capacitors. This paper summarizes the conceptual design features and furthermore gives an overview of the parameter space for possible applications at CERN.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB351
About •	paper received ※ 18 May 2021 paper accepted ※ 11 June 2021 issue date ※ 17 August 2021
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WEPAB378	Near-Infrared Laser System for Dielectric Laser Acceleration Experiments at SINBAD	laser, experiment, electron, acceleration	3596
	C. Mahnke, U. Grosse-Wortmann, I. Hartl, C.M. Heyl, Y. Hua, T. Lamb, Y. Ma, C. Mohr, J. Müller, S.H. Salman, S. Schulz, C. Vidoli DESY, Hamburg, Germany H. Çankaya CFEL, Hamburg, Germany
	The technique of dielectric laser acceleration (DLA) utilizes the strong field gradients generated by intense laser light near the surfaces of microscopic photonic structures, possibly allowing compact accelerator devices. We report on the infrared laser system at the SINBAD facility at DESY, where first DLA experiments with relativistic electrons pre-accelerated by the ARES linear accelerator started in late 2020. We constructed a low-noise Holmium fiber oscillator producing pulses at a wavelength of 2050 nm, seeding a Ho:YLF regenerative amplifier. Pulses of 2 mJ and 2 ps duration from the amplifier are transported over a distance of about 30 m to the DLA interaction point. The laser system is synchronized to the accelerator by locking the laser repetition rate to an RF master oscillator using an all-digital phase-locked loop, giving a residual timing jitter of about 45 fs. The digital locking scheme allows precise shifting of the relative timing between laser pulses and electrons without need for a dedicated optical delay line. It is planned to lock the system to the UV photocathode laser by means of an optical cross correlator further to improve the locking performance.
	Poster WEPAB378 [1.445 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB378
About •	paper received ※ 19 May 2021 paper accepted ※ 22 June 2021 issue date ※ 18 August 2021
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THXB02	Beam Arrival Stability at the European XFEL	FEL, laser, electron, feedback	3714
	M.K. Czwalinna, J. Kral, B. Lautenschlager, J. Müller, H. Schlarb, S. Schulz, B. Steffen DESY, Hamburg, Germany R. Boll, H. Kirkwood, J. Koliyadu, R. Letrun, J. Liu, F. Pallas, D.E. Rivas, T. Sato EuXFEL, Schenefeld, Germany
	Free electron laser facilities, such as the European XFEL, make increasingly high demands on the longterm temporal stability and uniformity of the electron bunches, as pump-probe experiments meanwhile aim for timing stabilities of few femtoseconds residual jitter only. For a beam-based feedback control of the linear accelerator, electro-optical bunch arrival-time monitors are deployed, achieving a time resolution better than 3 fs. In a first attempt, we recently demonstrated a beam-based feedback system, reducing the arrival time jitter of the electron bunches to the 10 fs level with stable operation over hours. For pump-probe experiments it is crucial to equally verify this new level of precision in the FEL pulse arrival time with independent methods. In this work, we are discussing first results from examining the facility-wide temporal stability at the European XFEL, with attention to the contributions of various sub-systems and on the different time scales.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXB02
About •	paper received ※ 19 May 2021 paper accepted ※ 20 July 2021 issue date ※ 23 August 2021
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THPAB314	Development of the Femtosecond Timing Distribution System for the Shanghai Soft X-Ray Free Electron Laser	FEL, laser, FEM, experiment	4406
	L. Feng, C.L. Li, B. Liu, J.G. Wang SARI-CAS, Pudong, Shanghai, People’s Republic of China X.T. Wang, W.Y. Zhang Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China
	High accuracy timing and synchronization system on femtosecond timescale play an important role for free-electron laser projects such as Shanghai Soft X-ray free-electron laser facility (SXFEL), and future Shanghai high repetition rate XFEL and Extreme light facility (SHINE). To meet the high precision synchronization requirements for both facilities, an optical-based timing distribution system is absolutely necessary. Such a system distributes the laser pulse train from a locked optical master oscillator through the fiber links, which stabilized by a balance optical cross-correlator based on a periodical-poled KTiOPO4 crystal. In this paper, the recent progress and experimental results of SXFEL and SHINE timing distribution system will be reported.
	Poster THPAB314 [0.351 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB314
About •	paper received ※ 20 May 2021 paper accepted ※ 15 July 2021 issue date ※ 22 August 2021
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Paper

Title

Other Keywords

Page

MOPAB124

APS Booster Injection Horizontal Trajectory Control Upgrade

injection, controls, booster, operation

449

C. Yao, J.R. Calvey, G.I. Fystro, A.F. Pietryla, H. Shang
ANL, Lemont, Illinois, USA

Funding: * Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-ACO₂-O6CH11357.
The APS booster is a 7-GeV electron synchrotron with a 0.5-second cycle. The booster runs a set of injection control programs that correct the beam trajectory in the horizontal and longitudinal planes, and the betatron tunes. Recently we developed a single-turn BPM controllaw program for horizontal trajectory control to replace the previous FFT based horizontal controllaw program. We present the system configuration and results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB124

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paper received ※ 15 May 2021 paper accepted ※ 27 May 2021 issue date ※ 21 August 2021

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MOPAB154

Multi-Cell Accelerating Structure Driven by a Lens-Focused Picosecond THz Pulse

laser, focusing, electron, acceleration

537

S.P. Antipov, S.V. Kuzikov
Euclid TechLabs, Solon, Ohio, USA
A.A. Vikharev
IAP/RAS, Nizhny Novgorod, Russia

Recently, gradients on the order of 1 GV/m level have been obtained in a form of a single cycle (~1 ps) THz pulses produced by conversion of a high peak power laser radiation in nonlinear crystals (~1 mJ, 1 ps, up to 3% conversion efficiency). Such high-intensity radiation can be utilized for charged particle acceleration. However, these pulses are short in time (~1ps) and broadband, therefore a new accelerating structure type is required. In this paper, we propose a novel structure based on focusing of THz radiation in accelerating cell and stacking such cells to achieve a long-range interaction required for an efficient acceleration process. We present an example in which a 100 microJoule THz pulse produces a 600 keV energy gain in 5 mm long 10 cell accelerating structure for an ultra-relativistic electron. This design can be readily extended to non-relativistic particles. Such structure had been laser microfabricated and appropriate dimensions were achieved.

Poster MOPAB154 [1.283 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB154

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paper received ※ 27 May 2021 paper accepted ※ 05 July 2021 issue date ※ 14 August 2021

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TUPAB078

Relative Timing Jitter Effects on Two-stage Seeded FEL at SHINE

FEL, laser, electron, radiation

1551

H.X. Yang
SINAP, Shanghai, People’s Republic of China
H.X. Deng, B. Liu, D. Wang, K.S. Zhou
SARI-CAS, Pudong, Shanghai, People’s Republic of China

Funding: The National Key Research and Development Program of China (Grants No. 2016YFA0401901, No. 2018YFE0103100) and the National Natural Science Foundation of China (Grants No. 11935020, No. 11775293).
The synchronization between the ultrashort electron beam and external seed laser is essential for seeded FELs, especially for a multi-stage one. In this paper, we demonstrate a simple method to obtain the correlations between the pulse energy and relative timing jitter for evaluating the corresponding effects. In this method, the sensitivity of the output FEL performance against electron beam properties is demonstrated by scanning the electron beam and seed lasers, and the fitted curve is used to predict the pulse energy in different timing jitter by random sampling. The results indicate that the pulse energy of the first-stage EEHG is more stable than the second-stage HGHG. Meanwhile, the rise of bunch charge from 100 pC to 300 pC can reduce the timing control requirement by a factor of least 3 for the RMS timing jitter in our numerical simulations based on the parameters of Shanghai High-Repetition-Rate XFEL and Extreme Light Facility. The timing jitter study can demonstrate the feasibility of the EEHG-HGHG cascading scheme in different current profiles for generating Fourier-transform-limited soft X-ray FEL.

Poster TUPAB078 [0.866 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB078

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paper received ※ 11 May 2021 paper accepted ※ 11 June 2021 issue date ※ 21 August 2021

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TUPAB181

Demonstration of Electron Cooling using a Pulsed Beam from an Electrostatic Electron Cooler

electron, experiment, space-charge, emittance

1827

M.W. Bruker, S.V. Benson, A. Hutton, K. Jordan, T. Powers, R.A. Rimmer, T. Satogata, A.V. Sy, H. Wang, S. Wang, H. Zhang, Y. Zhang
JLab, Newport News, Virginia, USA
J. Li, F. Ma, X.M. Ma, L.J. Mao, X.P. Sha, M.T. Tang, J.C. Yang, X.D. Yang, H.W. Zhao
IMP/CAS, Lanzhou, People’s Republic of China
H. Zhao
BNL, Upton, New York, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Electron cooling continues to be an invaluable technique to reduce and maintain the emittance in hadron storage rings in cases where stochastic cooling is inefficient and radiative cooling is negligible. Extending the energy range of electron coolers beyond what is feasible with the conventional, electrostatic approach necessitates the use of RF fields for acceleration and, thus, a bunched electron beam. To experimentally investigate how the relative time structure of the two beams affects the cooling properties, we have set up a pulsed-beam cooling device by adding a synchronized pulsing circuit to the conventional electron source of the CSRm cooler at Institute of Modern Physics *. We show the effect of the electron bunch length and longitudinal ion focusing strength on the temporal evolution of the longitudinal and transverse ion beam profile and demonstrate the detrimental effect of timing jitter as predicted by theory and simulations. Compared to actual RF-based coolers, the simplicity and flexibility of our setup will facilitate further investigations of specific aspects of bunched cooling such as synchro-betatron coupling and phase dithering.
* M. W. Bruker et al., Phys. Rev. Accel. Beams 24, 012801 (2021)

Poster TUPAB181 [3.699 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB181

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paper received ※ 19 May 2021 paper accepted ※ 15 June 2021 issue date ※ 21 August 2021

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TUPAB319

SNS Credited Beam Power Limit System Preliminary Design

PLC, target, controls, dipole

2242

C. Deibele
ORNL, Oak Ridge, Tennessee, USA
K.L. Mahoney
ORNL RAD, Oak Ridge, Tennessee, USA

The Controls Group at the Spallation Neutron Source (SNS) is designing a programmable signal processor based credited safety control that calculates pulsed beam power based on beam kinetic energy and charge. The system must reliably shut off the beam if the average power exceeds 2.145 MW averaged over 60 seconds. This paper discusses architecture and design choices needed to develop the system under the auspices of a programmable radiation-safety credit control.

Poster TUPAB319 [1.925 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB319

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paper received ※ 16 May 2021 paper accepted ※ 02 July 2021 issue date ※ 25 August 2021

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WEPAB052

Development of an EO Sampling System for the Analysis of THz Waves Generated by Coherent Cherenkov Radiation

radiation, electron, laser, experiment

2718

K. Murakoshi, Y. Koshiba, T. Murakami, K. Sakaue, Y. Tadenuma, P. Wang, M. Washio
Waseda University, Tokyo, Japan
R. Kuroda
AIST, Tsukuba, Japan
K. Sakaue
The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan

THz waves, located between microwaves and light waves, have transparency, directionality and fingerprint spectrum of specific materials. Therefore, they are expected to be useful for various applications. We have been studying THz waves generation via Cherenkov radiation with electron beams from a photocathode rf-gun. In our early studies, we have succeeded in the generation of coherent Cherenkov radiation by tilted electron beams using an rf-deflector. Furthermore, we have generated quasi-monochromatic THz waves by spatially modulated electron beams and have succeeded in its measurement by bandpass filters. This study aims to obtain the THz wave form in time domain by electro-optic (EO) sampling, which is an useful detection system for obtaining the information of the electric field and the phase simultaneously with high S/N. In this conference, we report about our probe laser system, results of the time-domain spectroscopy measurement of THz waves by EO sampling, and future prospects.

Poster WEPAB052 [0.861 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB052

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paper received ※ 19 May 2021 paper accepted ※ 07 June 2021 issue date ※ 31 August 2021

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WEPAB282

The Consolidation of the CERN Beam Interlock System

operation, diagnostics, controls, interface

3309

R.L. Johnson, C. Martin, T. Podzorny, I. Romera, R. Secondo, J.A. Uythoven
CERN, Geneva, Switzerland

The Beam Interlock System (BIS) is a machine protection system that provides essential interlock control throughout the CERN accelerator complex. The current BIS has been in service since 2006; as such, it is approaching the end of its operational lifetime, with most components being obsolete. A second version of the Beam Interlock System, "BIS2", is currently under development and will replace the current system. BIS2 aims to be more flexible by supplying additional on-board diagnostic tools, while also improving the overall safety by adding more redundancy. Crucially, BIS2 increases the number of critical paths that can be interlocked by almost 50%, providing an important flexibility for future additional interlocking requests. BIS2 will come into operation for the LHC in run 4 (2027) and will remain in operation until the end of the planned lifetime of HL-LHC. In this paper, we will focus on the Beam Interlock Controller Manager board (CIBM), which is at the heart of BIS2. Since this module works closely with many other systems that are similar in design to those in BIS1, we will compare how BIS2 improves upon BIS1, and justify the reasons why these changes were made.

Poster WEPAB282 [0.378 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB282

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paper received ※ 18 May 2021 paper accepted ※ 14 July 2021 issue date ※ 23 August 2021

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WEPAB285

High Resolution Arrival Time Measurement of the Seed Laser

laser, FEL, electron, experiment

3320

J.G. Wang, H.X. Deng, L. Feng, C.L. Li, B. Liu
SARI-CAS, Pudong, Shanghai, People’s Republic of China
X.T. Wang, W.Y. Zhang
Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China

The Shanghai soft X-ray Free-Electron Laser facility (SXFEL) is a fourth-generation linac-based light source, capable of producing X-ray pulses with a duration of tens of femtosecond. The seed laser for external seeding FEL, therefore, has tight requirements for relative arrival time to the electron bunch. To reach the required energy and wavelength for external seeding FEL, further optical amplification and frequency conversion is needed. These include reflection and propagation in different material and in air, in addition, also include the long laser transport beamline to the undulator, make the laser pulses arrival time influenced by environmental variation. To reach the required specification, high-resolution measurement of the laser arrival time is necessary. In this paper, we present a general concept for the measurement of the laser arrival time.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB285

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paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 12 August 2021

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WEPAB286

Design of the Laser-to-RF Synchronization at 1.3 GHz for SHINE

electron, laser, electronics, FEM

3323

J.G. Wang, H.X. Deng, L. Feng, C.L. Li, B. Liu
SARI-CAS, Pudong, Shanghai, People’s Republic of China
X.T. Wang, W.Y. Zhang
Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China

A next-generation photo-science facility like Shanghai HIgh repetition rate XFEL aNd Extreme light facility (SHINE) is aiming to generate femtosecond X-ray pulses with unprecedented brightness to film chemical and physical reactions with sub-atomic level spatio-temporal resolution. To fulfill this scientific goal, high-precision timing synchronization is essential. The pulsed optical synchronization has become an indispensable scheme for femtosecond precision synchronization of X-ray free-electron lasers. One of the critical tasks of pulsed optical synchronization is to synchronize various microwave sources. For the future SHINE, ultralow-noise pulses generated by a mode-locked laser are distributed over large distances via stabilized fiber links to all critical facility end-stations. In order to achieve low timing jitter and long-term stability of 1.3 GHz RF reference signal for the accuracy Low-Level RF(RF) field control, an Electro-optical intensity Modulator (EOM) based scheme is being developed at SHINE. In this paper, we present the progress on the design of the optical part and the integrated electronics of the laser-to-RF synchronization.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB286

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paper received ※ 20 May 2021 paper accepted ※ 12 July 2021 issue date ※ 28 August 2021

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WEPAB287

Upgrade of the ELBE Timing System

operation, gun, hardware, GUI

3326

M. Kuntzsch, M. Justus, A. Schwarz, K. Zenker
HZDR, Dresden, Germany
L. Krmpotic, U. Legat, U. Rojec
Cosylab, Ljubljana, Slovenia
Ž. Oven
COSYLAB, Control System Laboratory, Ljubljana, Slovenia

At the ELBE accelerator center a superconducting linac is operated to drive manifold secondary radiation sources like two infrared FELs, a positron source and a THz facility. The machine uses two injectors as electron sources that are accelerated in the main linac. The user experiments demand a large variety of bunch patterns from single shot to macro pulsed and cw beam at up to 26 MHz repetition rate. At ELBE a new timing system is being developed based on the MRF hardware platform and the MRF Timing System IOC. It uses two masters and a scalable number of connected receivers to generate the desired pulse patterns for operating the machine and to control user experiments. The contribution will show the architecture of the timing system, the control interfacing and performance measurements acquired on the test bench.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB287

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paper received ※ 21 May 2021 paper accepted ※ 01 July 2021 issue date ※ 13 August 2021

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WEPAB288

A New Timing System for PETRA IV

controls, FEL, storage-ring, hardware

3329

H. Lippek, A. Aghababyan, K. Brede, H.T. Duhme, M. Fenner, U. Hurdelbrink, H. Kay, H. Schlarb, T. Wilksen
DESY, Hamburg, Germany

At DESY an upgrade of the PETRA III synchrotron light source towards a fourth-generation, low emittance machine PETRA IV is currently being actively pursued. The realization of this new machine implies a new design of the timing and synchronization system since requirements on beam quality and controls will significantly change from the existing implementation at PETRA III. As of now the technical design phase of the PETRA IV project is in full swing. For the timing system the design process of the overall system as well as the evaluation of individual components has been started as of last year. Given the success of the at DESY developed MicroTCA.4-based timing system for the European XFEL accelerator it has been chosen to serve as a basis for the PETRA IV timing system developement as well. We present first design ideas of the major timing system hardware component, a MicroTCA.4-based AMC for distributing clocks, triggers and further bunch-synchronous information within the accelerator complex and to user experiments. First steps of an evaluation process for designing the AMC hardware are briefly illustrated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB288

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 10 August 2021

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WEPAB321

ALS-U Instrumentation Overview

instrumentation, electron, controls, hardware

3427

J.M. Weber, J.C. Bell, M.J. Chin, S. De Santis, R.F. Gunion, S. Murthy, W.E. Norum, G.J. Portmann, C. Serrano
LBNL, Berkeley, California, USA
W.K. Lewis
Osprey DCS LLC, Ocean City, USA

Funding: Work supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
The Advanced Light Source Upgrade (ALS-U) to a diffraction-limited storage ring with a small vacuum chamber diameter requires excellent orbit stability and a fast response orbit interlock for machine protection. The on-axis swap-out injection scheme and dual RF frequencies demand fast monitoring of pulsed injection magnets and a novel approach to timing. Recent development efforts at ALS and advances in PLLs, FPGAs, and RFSoCs that provide higher performance and mixed-signal integration can be leveraged for instrumentation solutions to these accelerator challenges. An overview of preliminary ALS-U instrumentation system designs and status will be presented.

Poster WEPAB321 [23.306 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB321

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paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 22 August 2021

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WEPAB351

Requirements for an Inductive Voltage Adder as Driver for a Kicker Magnet with Short Circuit Termination

kicker, impedance, simulation, flattop

3521

J. Ruf, M.J. Barnes, T. Kramer
CERN, Geneva 23, Switzerland
M. Sack
KIT, Karlsruhe, Germany

At CERN pulse generators based on Thyratron switches and SF6 gas filled pulse forming lines, used for driving kicker magnets, are to be replaced with semiconductor technology. Preliminary investigations show the inductive voltage adder is suitable as a pulse generator for this application. To increase the magnetic field without raising the system voltage, a short-circuit termination is often applied to a kicker magnet. Because of the electrical length of a transmission line magnet, wave propagation needs to be considered. To allow for the wavefront reflected from the short-circuit termination back to the generator, a novel approach for an inductive adder architecture has been investigated. It is based on a modified generator interface, circulating the current back into the load, until the stored energy is absorbed at the end of the pulse. This approach allows for a smaller magnetic core size compared to a conventional design with a matched load. Moreover, it enables more energy-efficient operation involving smaller storage capacitors. This paper summarizes the conceptual design features and furthermore gives an overview of the parameter space for possible applications at CERN.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB351

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paper received ※ 18 May 2021 paper accepted ※ 11 June 2021 issue date ※ 17 August 2021

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WEPAB378

Near-Infrared Laser System for Dielectric Laser Acceleration Experiments at SINBAD

laser, experiment, electron, acceleration

3596

C. Mahnke, U. Grosse-Wortmann, I. Hartl, C.M. Heyl, Y. Hua, T. Lamb, Y. Ma, C. Mohr, J. Müller, S.H. Salman, S. Schulz, C. Vidoli
DESY, Hamburg, Germany
H. Çankaya
CFEL, Hamburg, Germany

The technique of dielectric laser acceleration (DLA) utilizes the strong field gradients generated by intense laser light near the surfaces of microscopic photonic structures, possibly allowing compact accelerator devices. We report on the infrared laser system at the SINBAD facility at DESY, where first DLA experiments with relativistic electrons pre-accelerated by the ARES linear accelerator started in late 2020. We constructed a low-noise Holmium fiber oscillator producing pulses at a wavelength of 2050 nm, seeding a Ho:YLF regenerative amplifier. Pulses of 2 mJ and 2 ps duration from the amplifier are transported over a distance of about 30 m to the DLA interaction point. The laser system is synchronized to the accelerator by locking the laser repetition rate to an RF master oscillator using an all-digital phase-locked loop, giving a residual timing jitter of about 45 fs. The digital locking scheme allows precise shifting of the relative timing between laser pulses and electrons without need for a dedicated optical delay line. It is planned to lock the system to the UV photocathode laser by means of an optical cross correlator further to improve the locking performance.

Poster WEPAB378 [1.445 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB378

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paper received ※ 19 May 2021 paper accepted ※ 22 June 2021 issue date ※ 18 August 2021

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THXB02

Beam Arrival Stability at the European XFEL

FEL, laser, electron, feedback

3714

M.K. Czwalinna, J. Kral, B. Lautenschlager, J. Müller, H. Schlarb, S. Schulz, B. Steffen
DESY, Hamburg, Germany
R. Boll, H. Kirkwood, J. Koliyadu, R. Letrun, J. Liu, F. Pallas, D.E. Rivas, T. Sato
EuXFEL, Schenefeld, Germany

Free electron laser facilities, such as the European XFEL, make increasingly high demands on the longterm temporal stability and uniformity of the electron bunches, as pump-probe experiments meanwhile aim for timing stabilities of few femtoseconds residual jitter only. For a beam-based feedback control of the linear accelerator, electro-optical bunch arrival-time monitors are deployed, achieving a time resolution better than 3 fs. In a first attempt, we recently demonstrated a beam-based feedback system, reducing the arrival time jitter of the electron bunches to the 10 fs level with stable operation over hours. For pump-probe experiments it is crucial to equally verify this new level of precision in the FEL pulse arrival time with independent methods. In this work, we are discussing first results from examining the facility-wide temporal stability at the European XFEL, with attention to the contributions of various sub-systems and on the different time scales.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXB02

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paper received ※ 19 May 2021 paper accepted ※ 20 July 2021 issue date ※ 23 August 2021

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THPAB314

Development of the Femtosecond Timing Distribution System for the Shanghai Soft X-Ray Free Electron Laser

FEL, laser, FEM, experiment

4406

L. Feng, C.L. Li, B. Liu, J.G. Wang
SARI-CAS, Pudong, Shanghai, People’s Republic of China
X.T. Wang, W.Y. Zhang
Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China

High accuracy timing and synchronization system on femtosecond timescale play an important role for free-electron laser projects such as Shanghai Soft X-ray free-electron laser facility (SXFEL), and future Shanghai high repetition rate XFEL and Extreme light facility (SHINE). To meet the high precision synchronization requirements for both facilities, an optical-based timing distribution system is absolutely necessary. Such a system distributes the laser pulse train from a locked optical master oscillator through the fiber links, which stabilized by a balance optical cross-correlator based on a periodical-poled KTiOPO4 crystal. In this paper, the recent progress and experimental results of SXFEL and SHINE timing distribution system will be reported.

Poster THPAB314 [0.351 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB314

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paper received ※ 20 May 2021 paper accepted ※ 15 July 2021 issue date ※ 22 August 2021

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