IBIC2018 - List of Keywords (laser)

Paper	Title	Other Keywords	Page
MOPA09	Overview of Beam Instrumentation and Commissioning Results from the Coherent Electron Cooling Experiment at BNL	electron, cathode, optics, undulator	43
	T.A. Miller, J.C.B. Brutus, W.C. Dawson, D.M. Gassner, R.L. Hulsart, P. Inacker, J.P. Jamilkowski, D. Kayran, V. Litvinenko, C. Liu, R.J. Michnoff, M.G. Minty, P. Oddo, M.C. Paniccia, I. Pinayev, Z. Sorrell, J.E. Tuozzolo BNL, Upton, Long Island, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy The Coherent Electron Cooling (CeC) Proof-of-Principle experiment [1], installed in the RHIC tunnel at BNL, has completed its second run. In this experiment, an FEL is used to amplify patterns imprinted on the cooling electron beam by the RHIC ion bunches and then the imprinted pattern is fed back to the ions to achieve cooling of the ion beam. Diagnostics for the CeC experiment have been fully commissioned during this year’s run. An overview of the beam instrumentation is presented, this includes devices for measurements of beam current, position, profile, bunch charge, emittance, as well as gun photocathode imaging and FEL infra-red light emission diagnostics. Design details are discussed and beam measurement results are presented. [1] I. Pinayev, et al, ’First Results of Proof-of-Principle Experiment of Coherent Electron Cooling at BNL’ proceedings from IPAC 2018, Vancouver, CANADA
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPA09
About •	paper received ※ 04 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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MOPA14	Electron Spectrometer for a Low Charge Intermediate Energy LWFA Electron Beam Measurement	electron, dipole, experiment, vacuum	57
	A.V. Ottmar, Yu.I. Maltseva, T.V. Rybitskaya BINP SB RAS, Novosibirsk, Russia V. Gubin Institute of Laser Physics, SB RAS, Novosibirsk, Russia
	The Laser-driven Compton light source is under development in ILP SB RAS in collaboration with BINP SB RAS. Electron spectrometer for measurement of LWFA electron beam with energy in the range 10-150 MeV and bunch charge 1-10 pC is presented. Spectrometer based on permanent magnet and luminous screen with CCD registrar and this geometry was optimized for best measurements resolution in compromise with size limitations. Preliminary collimation of electron beam allows achieving energy resolution up to 5-10 % of top limit. System has been tested at the VEPP-5 linear electron accelerator and obtained results correspond to design objectives. Sensitivity of beam transverse charge density was experimentally fixed at 0.03 pC/mm², it is practically sufficient for our LWFA experiments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPA14
About •	paper received ※ 03 September 2018 paper accepted ※ 13 September 2018 issue date ※ 29 January 2019
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MOPA16	Design of a Compact Permanent Magnet Spectrometer for CILEX/APOLLON	electron, permanent-magnet, dipole, induction	61
	M. Khojoyan, A. Cauchois, J. Prudent, A. Specka LLR, Palaiseau, France
	Laser wakefield acceleration experiments make extensive use of small permanent magnets or magnet assemblies for analyzing and focusing electron beams produced in plasma accelerators. This choice is motivated by the ease of operation inside vacuum chambers, absence of power-supplies and feedthroughs, and potentially lower cost. Indeed, in these experiments space is at premium, and compactness is frequently required. At the same time, these magnets have to have a large angular acceptance for the divergent laser and electron beams which imposes constraint of the gap size. We will present the optimized design and characterization of a 100 mm long, 2.1 Tesla permanent magnet dipole. Furthermore, we will present the implementation of this magnet in a spectrometer that will measure the energy spectrum of electrons of [60-2000] MeV with a few percent resolution in the CILEX/APOLLON 10PW laser facility in France.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPA16
About •	paper received ※ 03 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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MOPB04	Progress in the Stripline Kicker for ELBE	kicker, simulation, electron, neutron	78
	Ch. Schneider, A. Arnold, J. Hauser, P. Michel HZDR, Dresden, Germany
	The linac based cw electron accelerator ELBE operates different secondary beamlines one at a time. For the future different end stations should be served simultaneously, hence specific bunch patterns have to be kicked into different beam-lines. The variability of the bunch pattern and the frequency resp. switching time are one of the main arguments for a stripline-kicker. A design with two tapered active electrodes and two ground fenders was optimized in time and frequency domain with the software package CST. From that a design has been transferred into a construction and was manufactured. The presentation summarises the recent results and the status of the project.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPB04
About •	paper received ※ 05 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019
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MOPC11	Data Acquisition System for Beam Instrumentation of SXFEL and DCLS	FEL, controls, data-acquisition, instrumentation	137
	Y.B. Yan SINAP, Shanghai, People’s Republic of China J. Chen, L.W. Lai, Y.B. Leng, C.L. Yu, L.Y. Yu, H. Zhao, W.M. Zhou SSRF, Shanghai, People’s Republic of China
	The high-gain free electron lasers have given scientists hopes for new scientific discoveries in many frontier research areas. The Shanghai X-Ray Free-Electron Laser (SXFEL) test facility is commissioning at the SSRF campus. The Dalian Coherent Light Source (DCLS) has successfully commissioned in the northeast of China, which is the brightest vacuum ultraviolet free electron laser facility. The data acquisition system for beam instrumentation is based on EPICS platform. The field programmable gate array (FPGA) and embedded controller are adopted for the signal processing and device control. The high-level applications are developed using Python. The details of the data acquisition system will be reported in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPC11
About •	paper received ※ 29 August 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019
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TUPA17	Status of the BNL LEReC Machine Protection System	gun, MMI, electron, operation	249
	S. Seletskiy, Z. Altinbas, D. Bruno, M.R. Costanzo, K.A. Drees, A.V. Fedotov, D.M. Gassner, X. Gu, L.R. Hammons, J. Hock, R.L. Hulsart, P. Inacker, J.P. Jamilkowski, D. Kayran, J. Kewisch, C. Liu, K. Mernick, T.A. Miller, M.G. Minty, M.C. Paniccia, W.E. Pekrul, I. Pinayev, V. Ptitsyn, V. Schoefer, L. Smart, K.S. Smith, R. Than, P. Thieberger, J.E. Tuozzolo, W. Xu, Z. Zhao BNL, Upton, Long Island, New York, USA
	The low energy RHIC Electron Cooler (LEReC) will be operating with 1.6-2.6 MeV electron beams having up to 140 kW power. It was determined that under the worst case scenario the missteered electron beam can damage the vacuum chamber and in-vacuum components within 40 us. Hence, the LEReC requires a dedicated fast machine protection system (MPS). The LEReC MPS has been designed and built and currently is under commissioning. In this paper we describe the most recent developments with the LEReC MPS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPA17
About •	paper received ※ 31 August 2018 paper accepted ※ 13 September 2018 issue date ※ 29 January 2019
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WEOA02	Optical Investigation to Minimize the Electron Bunch Arrival-time Jitter Between Femtosecond Laser Pulses and Electron Bunches for Laser-Driven Plasma Wakefield Accelerators	plasma, electron, ECR, polarization	332
	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) within the Project ’ MAKE-PWA. In a laser driven plasma based particle accelerators a stable synchronization of the electron bunch and of the plasma wakefield in the range of less than 2 fs is necessary in order to optimize the acceleration. For this purpose we are developing a new shot to shot feedback system with a time resolution of less than 1 fs. As a first step, stable THz pulses are generated by optical rectification of a fraction of the plasma generating high energy laser pulses in a nonlinear lithium niobate 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 1 fs. In this contribution we systematically investigate the influence of the optical properties as well as the theoretical description of the THz generation on the conversion efficiency of the generation of short THz pulses in undepleted approximation. We compare different approximations for the modeling of the generation dynamics and of the dielectric function in order to investigate the importance of a detailed description of the optical properties. First results by considering intensity decreasing of the laser pump will be presented. *The feedback system will be tested at the Accelerator R&D facility SINBAD (Short Innovative Bunches and Accelerators at DESY).
	Slides WEOA02 [1.605 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEOA02
About •	paper received ※ 04 September 2018 paper accepted ※ 10 September 2018 issue date ※ 29 January 2019
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WEOA03	First Electro-Optical Bunch Length Measurements from the European XFEL	electron, FEL, optics, detector	338
	B. Steffen, M.K. Czwalinna, C. Gerth, P. Peier DESY, Hamburg, Germany
	Three electro-optical bunch length detection systems based on spectral decoding have been installed and are being commissioned at the European XFEL. The systems are capable of recording individual longitudinal bunch profiles with sub-picosecond resolution at a bunch repetition rate 1.13 MHz. Bunch lengths and arrival times of entire bunch trains with single-bunch resolution have been measured as well as jitter and drifts for consecutive bunch trains. In this paper, we present first measurement results for the electro-optical detection system located after the second bunch compressor. A preliminary comparison with data from the bunch arrival-time monitor shows good agreement.
	Slides WEOA03 [4.496 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEOA03
About •	paper received ※ 05 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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WEOA04	The Application of Beam Arrival Time Measurement at SXFEL	cavity, FEL, experiment, electron	342
	S.S. Cao, J. Chen, Y.B. Leng, R.X. Yuan SINAP, Shanghai, People’s Republic of China
	Shanghai soft X-ray free electron laser (SXFEL) is able to generate high brightness and ultra-short light pulses. The generation of the light sources relies on the synchronization between seeded laser and electron bunch. Beam arrival time play an important role to keep the synchronization. For the SXFEL, a beam arrival time resolution under 100 fs is required. In this paper, the application of beam arrival time measurement scheme on SXFEL has been presented. The whole BAM system consists of four parts: beam arrival time monitor, electronic front-end, signal acquisition system, and high-level signal processing and presentation. Currently, four sets of beam arrival time monitors (BAMs) have been installed in the SXFEL and distributed in four different locations. The relevant beam arrival time experiment and beam flight time experiment based on the dual-cavities mixing method have also been performed so as to evaluate and analyze the beam status.
	Slides WEOA04 [4.588 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEOA04
About •	paper received ※ 05 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019
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WEPA06	Thermal Coefficient of Delay Measurement of the New Phase Stable Optical Fiber	detector, controls, power-supply, data-acquisition	383
	L. Liu, X. Ma, G. Pei IHEP, Beijing, People’s Republic of China
	The Thermal Coefficient of Delay (TCD) is an essen-tial parameter of optical fiber which determines a fiber’s phase transfer stability due to temperature variation. The TCD of a new phase stable single mode optical fiber (YPSOC) from Yangtze Optical Fibre and Cable Compa-ny (YOFC) is measured. The radio frequency (RF) signal is modulated to optical wave by a laser module which is transmitted through the 400-meter long YPSOC to be measured. The returned optical wave is demodulated to RF signal by the photodetector. A phase detector and a data acquisition module (DAQ) are used to acquire the phase difference between the forward and returned sig-nals. Two temperature-stabilized cabinets are designed to maintain and control the ambient temperature of the measurement system. The TCD of less than 10ps/km/K at room temperature is obtained. YPSOC and the meas-urement platform can be applied on signal transmission or measurement system that need to compensate the temperature drift.
	Poster WEPA06 [0.653 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA06
About •	paper received ※ 03 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019
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WEPA12	Differential Evolution Genetic Algorithm for Beam Bunch Temporal Reconstruction	radiation, electron, FEL, experiment	392
	D. Wu, T.H. He, C.L. Lao, P. Li, J. Liu, X. Luo, Q. Pan, L.J. Shan, X. Shen, J. Wang, D.X. Xiao, L.G. Yan, P. Zhang, K. Zhou CAEP/IAE, Mianyang, Sichuan, People’s Republic of China Y. Liu CAEP/IFP, Mainyang, Sichuan, People’s Republic of China
	Funding: Work supported by China National Natural Science Foundation of China with grant (11475159, 11505173, 11505174, 11575264, 11605190 and 11105019) Coherent radiation, such as coherent transition radiation, coherent diffraction radiation, coherent synchrotron radiation, etc, can be used to measure the longitudinal distribution of the electron beam bunch of any length, as long as the coherent radiation spectrum can be measured. In many cases, the Kramers-Krönig relationship is used to reconstruct the temporal distribution of the beam from the coherent radiation spectrum. However, the extrapolation of the low frequency will introduce the uncertainty of the reconstruction. In this paper, an algorithm of differential evolution (DE) for temporal reconstruction is discussed. The DE reconstruction works well for the complex and ultrashort distribution. It will be an effectIve tool to accurately measure the femtosecond bunch temporal structure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA12
About •	paper received ※ 07 September 2018 paper accepted ※ 13 September 2018 issue date ※ 29 January 2019
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WEPA13	Electro-Optic Modulator Based Beam Arrival Time Monitor for SXFEL	FEL, electron, pick-up, timing	396
	X.Q. Liu, L.F. Hua, L.W. Lai, Y.B. Leng, R.X. Yuan SINAP, Shanghai, People’s Republic of China N. Zhang SSRF, Shanghai, People’s Republic of China
	Beam arrival time monitor (BAM) is an important tool to investigate the temporal characteristic of elec-tron bunch in free electron laser (FEL) like Shanghai soft X-ray Free Electron Laser (SXFEL). Since the timing jitter of electron bunch will affect the FEL’s stability and the resolution of time-resolved experi-ment at FELs, it is necessary to precisely measure the electron bunch arrival time so as to reduce the timing jitter of the electron bunch with beam based feedback. The beam arrival time monitor based on electro-optic modulator (EOM) is already planned and will be de-veloped and tested at SXFEL in the next three years. Here the design and preliminary results of the EOM based beam arrival time monitor will be introduced in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA13
About •	paper received ※ 04 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019
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WEPA16	Micro-Bunching Instability Monitor for X-ray Free Electron Laser	radiation, electron, bunching, linac	404
	C. Kim, H.-S. Kang, G. Kim, I.S. Ko PAL, Pohang, Kyungbuk, Republic of Korea J.H. Ko POSTECH, Pohang, Kyungbuk, Republic of Korea
	A direct method was developed to measure the micro-bunching instability in the X-ray Free Electron Laser (XFEL). The micro-bunching instability comes from the interaction between the electron beam and the coherent synchrotron radiation (CSR), and the FEL intensity can be affected significantly by the micro-bunching instability. However, no effective method had been introduced to monitor the micro-bunching instability, so that we installed a CCD camera to measure the micro-bunching instability after the bunch compressor. The CCD camera showed the micro-bunching instability successfully, and more interesting features of the micro-bunching instability were revealed from it.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA16
About •	paper received ※ 09 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019
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WEPA20	First Results From the Bunch Arrival-Time Monitors at SwissFEL	FEL, pick-up, electron, MMI	420
	V.R. Arsov, P. Chevtsov, S. Hunziker, M.G. Kaiser, D. Llorente Sancho, A. Romann, V. Schlott, M. Stadler, D.M. Treyer PSI, Villigen PSI, Switzerland M. Dach Dach Consulting GmbH, Brugg, Switzerland
	Two Bunch Arrival-Time Monitors (BAM), based on fiber optical Mach-Zehnder intensity modulators, which encode the arrival-time information in the amplitude of the laser pulses delivered through a highly stable pulsed optical reference distribution system, have been commissioned and are operational at SwissFEL. The first BAM is at the RF-Gun, the second one is downstream the first bunch compressor. Both BAMs operate simultaneously and measure the arrival-time drift and jitter with less than 5 fs resolution. For the first time we have experimentally verified the excellent SwissFEL bunch stability. We have developed concepts and tested hardware, which enhance the commissioning and user operation. In particular we have successfully tested a tool for fast timing overlap between the electron bunch and the reference laser pulse, which allows fast system set-up and characterization. We have verified the capability for 2-bunch and 100 Hz operation. In comparison to the prototype detectors, which were operational at the SwissFEL test injector, we have achieved an improved BAM resolution in the range 10 pC - 200 pC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA20
About •	paper received ※ 05 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019
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WEPB04	Comparison of YAG Screens and LYSO Screens at PITZ	electron, HOM, emittance, distributed	438
	R. Niemczyk, P. Boonpornprasert, Y. Chen, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, C. Koschitzki, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, Y. Renier, F. Stephan, Q.T. Zhao DESY Zeuthen, Zeuthen, Germany W. Hillert University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	The Photo Injector Test facility at DESY in Zeuthen (PITZ) is dedicated to the development of high-brightness electron sources for free-electron lasers. At PITZ, to measure the emittance of space-charge-dominated beams, the slit scan technique is used. For slice emittance measurements a transverse deflecting structure (TDS) is employed. The electron beam distribution is measured by means of scintillator screens. Both the TDS and the slit mask reduce the signal strength, giving stringent requirements on the sensitivity of the screens. At PITZ, high-sensitivity Ce:LYSO screens have been installed at the same screen stations as the standard Ce:YAG screens to solve low-intensity issues. A comparison of both screens is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB04
About •	paper received ※ 03 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019
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WEPC06	The New Diagnostic Suite for the Echo Enabled Harmonic Generation Experiment at FERMI	electron, FEL, diagnostics, detector	501
	M. Veronese, A. Abrami, E. Allaria, M. Bossi, I. Cudin, M.B. Danailov, R. De Monte, M. Ferianis, F. Giacuzzo, S. Grulja, G. Kurdi, P. Rebernik Ribič, R. Sauro, G. Strangolino Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	The Echo Enabled Harmonic Generation (EEHG) experiment has been implemented on the FEL2 line of the FERMI FEL at Elettra (Italy). The main purpose is to validate the expected performance improvements at short wavelengths before a dedicated major upgrade is deployed. This paper describes the new diagnostics and the operational experience with them during the EEHG experiment. By means of a multi position vacuum vertical manipulator, different optical components are positioned on the electron and seed laser path. Both transverse and longitudinal measurements are performed. A YAG:Ce screen (e beam) and a terbium doped UV scintillator (laser) are imaged on a dedicated CMOS camera. For the temporal alignment, an OTR screen and a scattering surface are used to steer radiation from the e-beam and laser, onto a fast photodetector. Also coherent OTR radiation, due to micro-bunching, is acquired by means of a PbSe photodetector. Finally, for the normal EEHG operation, the laser beam is injected on the electron beam axis by means of a UV reflecting mirror. The results of the installed diagnostics commissioning are here presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPC06
About •	paper received ※ 05 September 2018 paper accepted ※ 13 September 2018 issue date ※ 29 January 2019
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Paper

Title

Other Keywords

Page

MOPA09

Overview of Beam Instrumentation and Commissioning Results from the Coherent Electron Cooling Experiment at BNL

electron, cathode, optics, undulator

43

T.A. Miller, J.C.B. Brutus, W.C. Dawson, D.M. Gassner, R.L. Hulsart, P. Inacker, J.P. Jamilkowski, D. Kayran, V. Litvinenko, C. Liu, R.J. Michnoff, M.G. Minty, P. Oddo, M.C. Paniccia, I. Pinayev, Z. Sorrell, J.E. Tuozzolo
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The Coherent Electron Cooling (CeC) Proof-of-Principle experiment [1], installed in the RHIC tunnel at BNL, has completed its second run. In this experiment, an FEL is used to amplify patterns imprinted on the cooling electron beam by the RHIC ion bunches and then the imprinted pattern is fed back to the ions to achieve cooling of the ion beam. Diagnostics for the CeC experiment have been fully commissioned during this year’s run. An overview of the beam instrumentation is presented, this includes devices for measurements of beam current, position, profile, bunch charge, emittance, as well as gun photocathode imaging and FEL infra-red light emission diagnostics. Design details are discussed and beam measurement results are presented.
[1] I. Pinayev, et al, ’First Results of Proof-of-Principle Experiment of Coherent Electron Cooling at BNL’ proceedings from IPAC 2018, Vancouver, CANADA

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPA09

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paper received ※ 04 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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MOPA14

Electron Spectrometer for a Low Charge Intermediate Energy LWFA Electron Beam Measurement

electron, dipole, experiment, vacuum

57

A.V. Ottmar, Yu.I. Maltseva, T.V. Rybitskaya
BINP SB RAS, Novosibirsk, Russia
V. Gubin
Institute of Laser Physics, SB RAS, Novosibirsk, Russia

The Laser-driven Compton light source is under development in ILP SB RAS in collaboration with BINP SB RAS. Electron spectrometer for measurement of LWFA electron beam with energy in the range 10-150 MeV and bunch charge 1-10 pC is presented. Spectrometer based on permanent magnet and luminous screen with CCD registrar and this geometry was optimized for best measurements resolution in compromise with size limitations. Preliminary collimation of electron beam allows achieving energy resolution up to 5-10 % of top limit. System has been tested at the VEPP-5 linear electron accelerator and obtained results correspond to design objectives. Sensitivity of beam transverse charge density was experimentally fixed at 0.03 pC/mm², it is practically sufficient for our LWFA experiments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPA14

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paper received ※ 03 September 2018 paper accepted ※ 13 September 2018 issue date ※ 29 January 2019

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MOPA16

Design of a Compact Permanent Magnet Spectrometer for CILEX/APOLLON

electron, permanent-magnet, dipole, induction

61

M. Khojoyan, A. Cauchois, J. Prudent, A. Specka
LLR, Palaiseau, France

Laser wakefield acceleration experiments make extensive use of small permanent magnets or magnet assemblies for analyzing and focusing electron beams produced in plasma accelerators. This choice is motivated by the ease of operation inside vacuum chambers, absence of power-supplies and feedthroughs, and potentially lower cost. Indeed, in these experiments space is at premium, and compactness is frequently required. At the same time, these magnets have to have a large angular acceptance for the divergent laser and electron beams which imposes constraint of the gap size. We will present the optimized design and characterization of a 100 mm long, 2.1 Tesla permanent magnet dipole. Furthermore, we will present the implementation of this magnet in a spectrometer that will measure the energy spectrum of electrons of [60-2000] MeV with a few percent resolution in the CILEX/APOLLON 10PW laser facility in France.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPA16

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paper received ※ 03 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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MOPB04

Progress in the Stripline Kicker for ELBE

kicker, simulation, electron, neutron

78

Ch. Schneider, A. Arnold, J. Hauser, P. Michel
HZDR, Dresden, Germany

The linac based cw electron accelerator ELBE operates different secondary beamlines one at a time. For the future different end stations should be served simultaneously, hence specific bunch patterns have to be kicked into different beam-lines. The variability of the bunch pattern and the frequency resp. switching time are one of the main arguments for a stripline-kicker. A design with two tapered active electrodes and two ground fenders was optimized in time and frequency domain with the software package CST. From that a design has been transferred into a construction and was manufactured. The presentation summarises the recent results and the status of the project.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPB04

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paper received ※ 05 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019

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MOPC11

Data Acquisition System for Beam Instrumentation of SXFEL and DCLS

FEL, controls, data-acquisition, instrumentation

137

Y.B. Yan
SINAP, Shanghai, People’s Republic of China
J. Chen, L.W. Lai, Y.B. Leng, C.L. Yu, L.Y. Yu, H. Zhao, W.M. Zhou
SSRF, Shanghai, People’s Republic of China

The high-gain free electron lasers have given scientists hopes for new scientific discoveries in many frontier research areas. The Shanghai X-Ray Free-Electron Laser (SXFEL) test facility is commissioning at the SSRF campus. The Dalian Coherent Light Source (DCLS) has successfully commissioned in the northeast of China, which is the brightest vacuum ultraviolet free electron laser facility. The data acquisition system for beam instrumentation is based on EPICS platform. The field programmable gate array (FPGA) and embedded controller are adopted for the signal processing and device control. The high-level applications are developed using Python. The details of the data acquisition system will be reported in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPC11

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paper received ※ 29 August 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019

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TUPA17

Status of the BNL LEReC Machine Protection System

gun, MMI, electron, operation

249

S. Seletskiy, Z. Altinbas, D. Bruno, M.R. Costanzo, K.A. Drees, A.V. Fedotov, D.M. Gassner, X. Gu, L.R. Hammons, J. Hock, R.L. Hulsart, P. Inacker, J.P. Jamilkowski, D. Kayran, J. Kewisch, C. Liu, K. Mernick, T.A. Miller, M.G. Minty, M.C. Paniccia, W.E. Pekrul, I. Pinayev, V. Ptitsyn, V. Schoefer, L. Smart, K.S. Smith, R. Than, P. Thieberger, J.E. Tuozzolo, W. Xu, Z. Zhao
BNL, Upton, Long Island, New York, USA

The low energy RHIC Electron Cooler (LEReC) will be operating with 1.6-2.6 MeV electron beams having up to 140 kW power. It was determined that under the worst case scenario the missteered electron beam can damage the vacuum chamber and in-vacuum components within 40 us. Hence, the LEReC requires a dedicated fast machine protection system (MPS). The LEReC MPS has been designed and built and currently is under commissioning. In this paper we describe the most recent developments with the LEReC MPS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPA17

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paper received ※ 31 August 2018 paper accepted ※ 13 September 2018 issue date ※ 29 January 2019

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WEOA02

Optical Investigation to Minimize the Electron Bunch Arrival-time Jitter Between Femtosecond Laser Pulses and Electron Bunches for Laser-Driven Plasma Wakefield Accelerators

plasma, electron, ECR, polarization

332

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) within the Project ’ MAKE-PWA.
In a laser driven plasma based particle accelerators a stable synchronization of the electron bunch and of the plasma wakefield in the range of less than 2 fs is necessary in order to optimize the acceleration. For this purpose we are developing a new shot to shot feedback system with a time resolution of less than 1 fs. As a first step, stable THz pulses are generated by optical rectification of a fraction of the plasma generating high energy laser pulses in a nonlinear lithium niobate 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 1 fs. In this contribution we systematically investigate the influence of the optical properties as well as the theoretical description of the THz generation on the conversion efficiency of the generation of short THz pulses in undepleted approximation. We compare different approximations for the modeling of the generation dynamics and of the dielectric function in order to investigate the importance of a detailed description of the optical properties. First results by considering intensity decreasing of the laser pump will be presented.
*The feedback system will be tested at the Accelerator R&D facility SINBAD (Short Innovative Bunches and Accelerators at DESY).

Slides WEOA02 [1.605 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEOA02

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paper received ※ 04 September 2018 paper accepted ※ 10 September 2018 issue date ※ 29 January 2019

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WEOA03

First Electro-Optical Bunch Length Measurements from the European XFEL

electron, FEL, optics, detector

338

B. Steffen, M.K. Czwalinna, C. Gerth, P. Peier
DESY, Hamburg, Germany

Three electro-optical bunch length detection systems based on spectral decoding have been installed and are being commissioned at the European XFEL. The systems are capable of recording individual longitudinal bunch profiles with sub-picosecond resolution at a bunch repetition rate 1.13 MHz. Bunch lengths and arrival times of entire bunch trains with single-bunch resolution have been measured as well as jitter and drifts for consecutive bunch trains. In this paper, we present first measurement results for the electro-optical detection system located after the second bunch compressor. A preliminary comparison with data from the bunch arrival-time monitor shows good agreement.

Slides WEOA03 [4.496 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEOA03

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paper received ※ 05 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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WEOA04

The Application of Beam Arrival Time Measurement at SXFEL

cavity, FEL, experiment, electron

342

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

Shanghai soft X-ray free electron laser (SXFEL) is able to generate high brightness and ultra-short light pulses. The generation of the light sources relies on the synchronization between seeded laser and electron bunch. Beam arrival time play an important role to keep the synchronization. For the SXFEL, a beam arrival time resolution under 100 fs is required. In this paper, the application of beam arrival time measurement scheme on SXFEL has been presented. The whole BAM system consists of four parts: beam arrival time monitor, electronic front-end, signal acquisition system, and high-level signal processing and presentation. Currently, four sets of beam arrival time monitors (BAMs) have been installed in the SXFEL and distributed in four different locations. The relevant beam arrival time experiment and beam flight time experiment based on the dual-cavities mixing method have also been performed so as to evaluate and analyze the beam status.

Slides WEOA04 [4.588 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEOA04

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paper received ※ 05 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019

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WEPA06

Thermal Coefficient of Delay Measurement of the New Phase Stable Optical Fiber

detector, controls, power-supply, data-acquisition

383

L. Liu, X. Ma, G. Pei
IHEP, Beijing, People’s Republic of China

The Thermal Coefficient of Delay (TCD) is an essen-tial parameter of optical fiber which determines a fiber’s phase transfer stability due to temperature variation. The TCD of a new phase stable single mode optical fiber (YPSOC) from Yangtze Optical Fibre and Cable Compa-ny (YOFC) is measured. The radio frequency (RF) signal is modulated to optical wave by a laser module which is transmitted through the 400-meter long YPSOC to be measured. The returned optical wave is demodulated to RF signal by the photodetector. A phase detector and a data acquisition module (DAQ) are used to acquire the phase difference between the forward and returned sig-nals. Two temperature-stabilized cabinets are designed to maintain and control the ambient temperature of the measurement system. The TCD of less than 10ps/km/K at room temperature is obtained. YPSOC and the meas-urement platform can be applied on signal transmission or measurement system that need to compensate the temperature drift.

Poster WEPA06 [0.653 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA06

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paper received ※ 03 September 2018 paper accepted ※ 12 September 2018 issue date ※ 29 January 2019

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WEPA12

Differential Evolution Genetic Algorithm for Beam Bunch Temporal Reconstruction

radiation, electron, FEL, experiment

392

D. Wu, T.H. He, C.L. Lao, P. Li, J. Liu, X. Luo, Q. Pan, L.J. Shan, X. Shen, J. Wang, D.X. Xiao, L.G. Yan, P. Zhang, K. Zhou
CAEP/IAE, Mianyang, Sichuan, People’s Republic of China
Y. Liu
CAEP/IFP, Mainyang, Sichuan, People’s Republic of China

Funding: Work supported by China National Natural Science Foundation of China with grant (11475159, 11505173, 11505174, 11575264, 11605190 and 11105019)
Coherent radiation, such as coherent transition radiation, coherent diffraction radiation, coherent synchrotron radiation, etc, can be used to measure the longitudinal distribution of the electron beam bunch of any length, as long as the coherent radiation spectrum can be measured. In many cases, the Kramers-Krönig relationship is used to reconstruct the temporal distribution of the beam from the coherent radiation spectrum. However, the extrapolation of the low frequency will introduce the uncertainty of the reconstruction. In this paper, an algorithm of differential evolution (DE) for temporal reconstruction is discussed. The DE reconstruction works well for the complex and ultrashort distribution. It will be an effectIve tool to accurately measure the femtosecond bunch temporal structure.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA12

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paper received ※ 07 September 2018 paper accepted ※ 13 September 2018 issue date ※ 29 January 2019

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WEPA13

Electro-Optic Modulator Based Beam Arrival Time Monitor for SXFEL

FEL, electron, pick-up, timing

396

X.Q. Liu, L.F. Hua, L.W. Lai, Y.B. Leng, R.X. Yuan
SINAP, Shanghai, People’s Republic of China
N. Zhang
SSRF, Shanghai, People’s Republic of China

Beam arrival time monitor (BAM) is an important tool to investigate the temporal characteristic of elec-tron bunch in free electron laser (FEL) like Shanghai soft X-ray Free Electron Laser (SXFEL). Since the timing jitter of electron bunch will affect the FEL’s stability and the resolution of time-resolved experi-ment at FELs, it is necessary to precisely measure the electron bunch arrival time so as to reduce the timing jitter of the electron bunch with beam based feedback. The beam arrival time monitor based on electro-optic modulator (EOM) is already planned and will be de-veloped and tested at SXFEL in the next three years. Here the design and preliminary results of the EOM based beam arrival time monitor will be introduced in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA13

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paper received ※ 04 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019

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WEPA16

Micro-Bunching Instability Monitor for X-ray Free Electron Laser

radiation, electron, bunching, linac

404

C. Kim, H.-S. Kang, G. Kim, I.S. Ko
PAL, Pohang, Kyungbuk, Republic of Korea
J.H. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea

A direct method was developed to measure the micro-bunching instability in the X-ray Free Electron Laser (XFEL). The micro-bunching instability comes from the interaction between the electron beam and the coherent synchrotron radiation (CSR), and the FEL intensity can be affected significantly by the micro-bunching instability. However, no effective method had been introduced to monitor the micro-bunching instability, so that we installed a CCD camera to measure the micro-bunching instability after the bunch compressor. The CCD camera showed the micro-bunching instability successfully, and more interesting features of the micro-bunching instability were revealed from it.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA16

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paper received ※ 09 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019

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WEPA20

First Results From the Bunch Arrival-Time Monitors at SwissFEL

FEL, pick-up, electron, MMI

420

V.R. Arsov, P. Chevtsov, S. Hunziker, M.G. Kaiser, D. Llorente Sancho, A. Romann, V. Schlott, M. Stadler, D.M. Treyer
PSI, Villigen PSI, Switzerland
M. Dach
Dach Consulting GmbH, Brugg, Switzerland

Two Bunch Arrival-Time Monitors (BAM), based on fiber optical Mach-Zehnder intensity modulators, which encode the arrival-time information in the amplitude of the laser pulses delivered through a highly stable pulsed optical reference distribution system, have been commissioned and are operational at SwissFEL. The first BAM is at the RF-Gun, the second one is downstream the first bunch compressor. Both BAMs operate simultaneously and measure the arrival-time drift and jitter with less than 5 fs resolution. For the first time we have experimentally verified the excellent SwissFEL bunch stability. We have developed concepts and tested hardware, which enhance the commissioning and user operation. In particular we have successfully tested a tool for fast timing overlap between the electron bunch and the reference laser pulse, which allows fast system set-up and characterization. We have verified the capability for 2-bunch and 100 Hz operation. In comparison to the prototype detectors, which were operational at the SwissFEL test injector, we have achieved an improved BAM resolution in the range 10 pC - 200 pC.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA20

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paper received ※ 05 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019

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WEPB04

Comparison of YAG Screens and LYSO Screens at PITZ

electron, HOM, emittance, distributed

438

R. Niemczyk, P. Boonpornprasert, Y. Chen, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, C. Koschitzki, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, Y. Renier, F. Stephan, Q.T. Zhao
DESY Zeuthen, Zeuthen, Germany
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

The Photo Injector Test facility at DESY in Zeuthen (PITZ) is dedicated to the development of high-brightness electron sources for free-electron lasers. At PITZ, to measure the emittance of space-charge-dominated beams, the slit scan technique is used. For slice emittance measurements a transverse deflecting structure (TDS) is employed. The electron beam distribution is measured by means of scintillator screens. Both the TDS and the slit mask reduce the signal strength, giving stringent requirements on the sensitivity of the screens. At PITZ, high-sensitivity Ce:LYSO screens have been installed at the same screen stations as the standard Ce:YAG screens to solve low-intensity issues. A comparison of both screens is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPB04

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paper received ※ 03 September 2018 paper accepted ※ 11 September 2018 issue date ※ 29 January 2019

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WEPC06

The New Diagnostic Suite for the Echo Enabled Harmonic Generation Experiment at FERMI

electron, FEL, diagnostics, detector

501

M. Veronese, A. Abrami, E. Allaria, M. Bossi, I. Cudin, M.B. Danailov, R. De Monte, M. Ferianis, F. Giacuzzo, S. Grulja, G. Kurdi, P. Rebernik Ribič, R. Sauro, G. Strangolino
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The Echo Enabled Harmonic Generation (EEHG) experiment has been implemented on the FEL2 line of the FERMI FEL at Elettra (Italy). The main purpose is to validate the expected performance improvements at short wavelengths before a dedicated major upgrade is deployed. This paper describes the new diagnostics and the operational experience with them during the EEHG experiment. By means of a multi position vacuum vertical manipulator, different optical components are positioned on the electron and seed laser path. Both transverse and longitudinal measurements are performed. A YAG:Ce screen (e beam) and a terbium doped UV scintillator (laser) are imaged on a dedicated CMOS camera. For the temporal alignment, an OTR screen and a scattering surface are used to steer radiation from the e-beam and laser, onto a fast photodetector. Also coherent OTR radiation, due to micro-bunching, is acquired by means of a PbSe photodetector. Finally, for the normal EEHG operation, the laser beam is injected on the electron beam axis by means of a UV reflecting mirror. The results of the installed diagnostics commissioning are here presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPC06

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paper received ※ 05 September 2018 paper accepted ※ 13 September 2018 issue date ※ 29 January 2019

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