IPAC2017 - List of Keywords (linac)

Paper	Title	Other Keywords	Page
MOXAA1	Commissioning of the European XFEL Accelerator	operation, electron, undulator, emittance	1
	W. Decking, H. Weise DESY, Hamburg, Germany
	The European XFEL uses the world's largest superconducting RF installation to drive three independent SASE FELs. After eight years of construction the facility is now brought into operation. First experience with the superconducting accelerator as well as beam commissioning results will be presented. The path to the first user experiments will be laid down.
	Slides MOXAA1 [22.967 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOXAA1
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MOXBA1	Progress on the ESS Project Construction	target, controls, cryomodule, klystron	7
	R. Garoby ESS, Lund, Sweden
	The construction of the European Spallation Source (ESS) is advancing at a high pace with the support of many laboratories and institutions all over Europe. Prototyping and manufacturing for the accelerator are in full swing in more than 23 laboratories distributed over 12 European partner countries. The origin and goals of the ESS will be briefly outlined in this paper. The milestones achieved, both in Lund and at the partner labs will be described as well as the plans up to operations.
	Slides MOXBA1 [76.192 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOXBA1
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MOYCA1	Ultimate Field Gradient in Metallic Structures	klystron, collider, damping, linear-collider	24
	W. Wuensch CERN, Geneva, Switzerland
	Significant progress has been made over the past decade by studies of normal-conducting linear colliders, NLC/JLC (Next/Japanese Linear Collider) and CLIC (Compact Linear Collider), to raise achievable accelerating gradient from the range of 20-30 MV/m up to 100-120 MV/m. The gain has come through a greatly increased understanding of high-power rf phenomena, development of quantitative high-gradient rf design methods, refinements in cavity fabrication techniques and through development of high peak rf power sources. Recently accelerating gradients in excess of 100 MV/m, at very low breakdown rates, have been successfully achieved with new techniques of conditioning in numerous prototypes at different laboratories. The talk will report on the impact of these new results on the understanding of the physics of breakdown and of conditioning, and on the ultimate gradients that can be expected in metallic RF structures.
	Slides MOYCA1 [52.087 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOYCA1
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MOPAB016	Beam Diagnostic and Control Systems for AREAL 50 MeV Linac	controls, electron, emittance, diagnostics	114
	V. Sahakyan, G.A. Amatuni, A. Azatyan, B. Grigoryan, N. Martirosyan, A. Sargsyan, V.M. Tsakanov, G.S. Zanyan CANDLE SRI, Yerevan, Armenia
	Advanced Research Electron Accelerator Laboratory (AREAL) is an electron linear accelerator project with a laser driven RF gun that has been constructed at CANDLE Synchrotron Research Institute. After the completion of the first phase, which implies the operation of a 5 MeV gun section, the second phase of facility development (energy enhancement up to 50 MeV) is in progress. In the present paper the description of corresponding upgrades for diagnostic and control systems is given.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB016
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MOPAB021	Performance of OTR and Scintillator View Screens for the ARIEL Electron Linac	target, optics, radiation, scattering	117
	D.W. Storey, J.M. Abernathy, D. Karlen, M.O. Pfleger, P.R. Poffenberger Victoria University, Victoria, B.C., Canada P.S. Birney, P.E. Dirksen, S.R. Koscielniak, M. Lenckowski TRIUMF, Vancouver, Canada
	The ARIEL electron linac is a 0.3 MW CW accelerator, extensible to 0.5 MW, being installed at TRIUMF for radioactive beam production. To date, 17 view screen monitors have been installed along the beamline and have proven to be essential tools in the commissioning of e-linac systems. These are populated by two types of beam targets: P46 scintillator screens which provide diagnostics for low duty factor operation, while at locations with beam energies at and above 10 MeV, OTR foils using either Pyrolytic Graphite or Niobium foils are included to provide coverage up to 100's of μA average beam current. The design of the view screen is described including the image acquisition system and beam target selection. The performance thus far of the OTR foils under low duty factor commissioning is presented including quantification of the OTR emission distribution, thermal studies, and transmission of the beam through the linac after intercepting a foil.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB021
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MOPAB022	Fabrication Studies of a 650 MHz Superconducting RF Deflecting Mode Cavity for the ARIEL Electron Linac	cavity, niobium, electron, impedance	120
	D.W. Storey, R.E. Laxdal, B. Matheson, N. Muller TRIUMF, Vancouver, Canada D.W. Storey Victoria University, Victoria, B.C., Canada
	A 650 MHz RF deflecting mode cavity is required for the ARIEL electron Linac to separate interleaved beams bound for either rare isotope production or a recirculation loop containing a Free Electron Laser. An RF separator will allow both modes to run simultaneously by imparting opposite transverse deflection to adjacent bunches at 1.3 GHz. The SRF cavity has been designed to provide up to 0.6 MV transverse voltage for operation with up to a 50 MeV CW electron beam. The design was optimised for compact geometry with high shunt impedance. Due to the low dissipated power, the cavity will operate at 4 K and allows for investigations into low cost fabrication techniques. The cavity is being machined from bulk reactor grade ingot Niobium and welds will be performed using TIG welding in an ultra-pure Argon chamber. Results of fabrication studies will be presented as well as measurements performed on a copper prototype cavity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB022
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MOPAB024	Proposal to Observe Half-Bare Electrons on a 40-MeV LINAC	electron, radiation, experiment, laser	126
	N. Delerue, S. Jenzer, V. Khodnevych, A. Migayron LAL, Orsay, France N.F. Shul'ga NSC/KIPT, Kharkov, Ukraine S. Trofymenko KhNU, Kharkov, Ukraine
	Funding: CNRS/IN2P3 and Joint Laboratory France-Ukraine IDEATE In different processes of relativistic electron interaction with substance and external fields, the electron loses part of its Coulomb field and becomes half-bare. Such state of electron significantly modifies the characteristics of its electromagnetic radiation during further interaction of the particle with substance. We propose to study the influence of the half-bare state of electron upon its transition radiation (TR). The existence of such influence for the case of electron undressing at its scattering was theoretically predicted. We intend to obtain the electrons in half-bare state in the result of their crossing of a conducting screen such as a TR screen. We propose to investigate the influence of the half-bare state of electron in this process upon TR generated by such electron on a downstream TR screen situated on some distance from the upstream screen which undresses the particle. Calculations are presented for the case of a 45-MeV linac and the distance between the screens in the region between 100 mm and 300 mm. The proposed experiment is expected to reveal new features of TR signal in such process comparing to previous measurements. N.F. Shul'ga, S.V. Trofymenko, V.V. Syshchenko, JETP Lett. 93 (2011) 1. Y. Shibata, K. Ishi, T. Tokahashi et al., Phys. Rev. E 49 (1994) 785.
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MOPAB025	Measurement of the Polarisation of Coherent Smith-Purcell Radiation in the SOLEIL Linac	radiation, polarization, detector, experiment	129
	N. Delerue, S. Jenzer, V. Khodnevych LAL, Orsay, France N. Hubert, M. Labat, J.-P. Pollina, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	Funding: CNRS/IN2P3, Université Paris-Sud and ANR (contract ANR-12-JS05-0003-01) SPESO is an experiment installed in the Linac of Synchrotron SOLEIL to study the Coherent Smith-Purcell radiation produced when a grating is approached from the beam. The detectors used to measure this radiation are mounted on 3-translation axis and 2 rotation axis. This allows measurements of the radiation emission map around the grating. In addition a polarizer has been added in 2016 allowing to study the two polarization components of the radiation in this map. Preliminary results of this mapping will be presented.
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MOPAB033	Optics Development and Trajectory Tuning of BERLinPro at Low Energies	gun, booster, diagnostics, SRF	153
	B.C. Kuske, M. Abo-Bakr HZB, Berlin, Germany
	Funding: Work supported by the German Bundesministerium fr Bildung und Forschung, Land Berlin and grants of the Helmholtz Association The Berlin Energy Recovery Linac project has taken shape during the past year. The magnets have been set up in the newly constructed subterraneous hall; first electrons are expected in the SRF-gun test laboratory in June 2017. Starting in February 2018 the complete gun module will be transferred to the accelerator hall for the commissioning of BERLinPro. For the first months, operation is planned without further accelerating structures (booster and linac), due to delays in their fabrication. Several modes of operation are applicable at this early stage [1]. The available hardware is displayed and the adapted optics at 2.7 MeV and at 6.5 MeV (including the booster) are presented. The trajectory distortions under the influence of the earth magnetic field are studied. The concept for trajectory correction is outlined.
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MOPAB048	Simulation of fs Bunch Length Determination with the 3-Phase Method and THz Dielectric Loaded Waveguides	injection, space-charge, simulation, electron	199
	T. Vinatier, R.W. Aßmann, U. Dorda, B. Marchetti DESY, Hamburg, Germany
	In this paper, we investigate with ASTRA simulations the capability of the 3-phase method to reconstruct the length of a fs electron bunch. We show that a standard 3 GHz travelling wave accelerating structure is not suited for this purpose, because of the too important effect of the space-charge forces and of the too small variations of the induced energy spread with the bunch injection phase. Our simulations demonstrate that the use of dielectric-loaded waveguides driven by THz pulses would allow overcoming these two limitations and possibly achieving an ultimate resolution better than 5% for the determination of a 6.25 fs rms bunch length at 100 MeV energy and 1 pC charge. The next steps of the study to better evaluate, in simulations and experiments, the possible sources of degradation of the 3-phase method resolution are also mentioned.
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MOPAB049	Development of a Focusing System for the AXSIS Project	solenoid, quadrupole, plasma, focusing	203
	T. Vinatier, R.W. Aßmann, U. Dorda, B. Marchetti DESY, Hamburg, Germany
	In this paper, we investigate with ASTRA simulations the achievable performances for several focusing systems considered in the AXSIS project. We focus our attention on the requirements in terms of position of the focal point and bunch transverse size at this point. We show that they cannot be fulfilled with a solenoid resistive electro-magnet, but that it is possible when using a solenoid permanent magnet. The use of a quadrupole doublet proves to be adequate to fulfil the requirement on the position of the focal point and be very close to the one on the bunch transverse size, which could possibly be achieved by a further optimization of the parameters of the doublet. Finally, we also investigate the possibility to use an active plasma lens, showing that it could easily fulfil the requirements but that several points must be carefully studied before considering its implementation.
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MOPAB057	Analysis and Correction of Geometrical Non-Linearities of ELI-NP BPMs on Position and Current Measurements	electron, laser, photon, instrumentation	235
	G. Franzini, F. Cioeta, O. Coiro, V.L. Lollo, D. Pellegrini, S. Pioli, A. Stella, A. Variola INFN/LNF, Frascati (Roma), Italy M. Marongiu INFN-Roma, Roma, Italy A. Mostacci University of Rome La Sapienza, Rome, Italy A.A. Nosych ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain L. Sabato U. Sannio, Benevento, Italy
	The advanced source of Gamma-ray photons will be soon built near Bucharest (Romania) by an European consortium (EurogammaS) led by INFN, as part of the ELI-NP (Extreme Light Infrastructure-Nuclear Physics). It will generate photons by Compton back-scattering in the collision between a multi-bunch electron beam, at a maximum energy of 720 MeV, and a high intensity recirculated laser pulse. An S-Band photo-injector and the following C-band Linac, which are under construction, will operate at 100Hz repetition rate with macro pulses of 32 electron bunches, separated by 16ns and with 250pC nominal charge. Stripline and cavity BPMs will be installed along the linac, in order to measure both the position and charge of the electron beam. Stripline BPM response can be considered linear within a limited area around the BPM origin. In order to use the full BPM acceptance area, without accuracy losses due to non-linearities, we plan to use correction algorithms, developed on the basis of simulations and measurements of BPMs response. In particular, suitable high-order surface polynomials will be used.
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MOPAB058	Optical Issues for the Diagnostic Stations for the ELI-NP Compton Gamma Source	target, diagnostics, electron, laser	238
	M. Marongiu, D. Cortis INFN-Roma, Roma, Italy E. Chiadroni, F. Cioeta, G. Di Pirro, G. Franzini, V. Shpakov, A. Stella, A. Variola INFN/LNF, Frascati (Roma), Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy A. Mostacci, L. Palumbo University of Rome La Sapienza, Rome, Italy L. Sabato U. Sannio, Benevento, Italy
	A high brightness electron Linac is being built in the Compton Gamma Source at the ELI Nuclear Physics facility in Romania. To achieve the design luminosity, a train of 32 bunches, 16 ns spaced, with a nominal charge of 250 pC will collide with the laser beam in the interaction point. Electron beam spot size is measured with optical transition radiation (OTR) profile monitors. In order to measure the beam properties, the optical radiation detecting system must have the necessary accuracy and resolution. This paper deals with the studies of different optic configurations to achieve the magnification, resolution and accuracy in order to measure very small beam (below 30 um) or to study the angular distribution of the OTR and therefore the energy of the beam. Several configurations of the optical detection line will be studied both with simulation tools (e.g. Zemax) and experimentally. The paper will deal also with the sensibility of optic system (in terms of depth of field, magnification and resolution) to systematic errors.
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MOPAB059	Energy Chirp Measurements by Means of an RF Deflector: a Case Study the Gamma Beam Source LINAC at ELI-NP	electron, brightness, detector, simulation	242
	L. Sabato U. Sannio, Benevento, Italy P. Arpaia, A. Liccardo Naples University Federico II, Science and Technology Pole, Napoli, Italy A. Mostacci, L. Palumbo University of Rome La Sapienza, Rome, Italy A. Variola INFN/LNF, Frascati (Roma), Italy
	RF Deflector (RFD) based measurements are widely used in high–brightness electron LINAC around the world in order to measure the ultra–short electron bunch length. The RFD provides a vertical kick to the particles of the electron bunch according to their longitudinal positions. In this paper, a measurement technique for the bunch length and other bunch proprieties, based on the usage of an RFD, is proposed. The basic idea is to obtain information about the bunch length, energy chirp, and energy spread from vertical spot size measurements varying the RFD phase, because they add contributions on this quantity. The case study is the Gamma Beam System (GBS), the Compton Source being built in the Extreme Light Infrastructure–Nuclear Physics (ELI–NP) facility. The ELEctron Generation ANd Tracking (ELEGANT) code is used for tracking the particles from RFD to the measurement screen.
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MOPAB061	DAΦNE BTF Improvements of the Transverse Beam Diagnostics	software, detector, timing, positron	250
	P. Valente INFN-Roma, Roma, Italy B. Buonomo, D.G.C. Di Giulio, L.G. Foggetta INFN/LNF, Frascati (Roma), Italy
	The DAΦNE BTF (beam-test facility) can provide electrons and positrons, tuning at runtime different beam parameters: energy (from about 50 MeV up to 750 MeV for e^- and 540 MeV for e+), intensity (from single particle up to 10¹⁰/bunch) and pulse length (in the range 1.5-40 ns) up to 49 Hz, depending on the operations of the DAΦNE collider. The beam spot and divergence can be adjusted, down to sub-mm sizes and 2 mrad (downstream of the vacuum beam-pipe exit window), matching the user needs. We describe of the BTF beam transverse monitor systems based on FitPIX detectors, operating in bus synchronization mode externally timed to the BTF beam. We also describe our custom software allowing the acquisition and synchronization of the beam diagnostics with the users data, using TCP/IP calls to MEMCACHED. The performance of the system in a variety of beam intensity, energy and focusing conditions is reported.
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MOPAB067	Response of Scintillating Screens to High Charge Density Electron Beam	electron, quadrupole, diagnostics, experiment	268
	F. Miyahara, S. Kishimoto, M. Satoh, Y. Seimiya, T. Suwada KEK, Ibaraki, Japan M. Koshimizu Tohoku University, School of Science, Sendai, Japan
	Inorganic scintillating screens are very useful tool to measure transverse profile of charged particle beams. The cerium-doped yttrium:aluminum:garnet (YAG:Ce) crystal scintillator is used in many accelerating facilities. The scintillating screen shows good resolution comparable to that of OTR screen. However, response to high charge density electron beam, more than 10 nC per square millimeter, has not been clarified. In KEK e⁺/e⁻ injector linac, the charge areal density (σ) will exceed 25 nC per square mm. Thus, beam tests has been performed on YAG:Ce, LYSO, and BGO crystals for 1.5 GeV, 1 nC/bunch electron beam at the linac. Saturation of the luminescence which causes degradation of the resolution has been observed above 1 nC per square mm in those crystals. We will report the response of the scintillating screens to high charge density electron beam and discuss the degradation of the resolution due to the saturation of the light yield.
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MOPAB070	Beam Position Measurement During Multi-Turn Painting Injection at the J-PARC RCS	injection, operation, proton, synchrotron	277
	N. Hayashi, A. Miura, P.K. Saha, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	Multi-turn painting injection scheme is important for high intensity proton accelerators. At the J-PARC RCS, a transverse painting scheme was adapted by adding vertical painting magnets to the beam transport line before the injection point, with horizontal painting being performed by a set of dedicated pulse magnets in the ring. To establish a transverse painting condition, it is usual to base on the pulse magnet current pattern. However, it is more desirable to directly measure the beam orbit time variation for evaluation. A linac beam was chopped to match the ring RF bucket. We thought that it would be difficult to measure the position for each pulse; however, the average position could be extracted by introducing a particular device. For the beam injected into the ring, because the linac RF frequency component was diminished due to debunching quickly, one could determine its position in the beginning of the injection period. However, due to rebunching effect the position determination becomes difficult. This problem needs to be resolved.
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MOPAB071	A Beam Position Monitor for the Diagnostic Line in MEBT2 of J-PARC Linac	diagnostics, pick-up, impedance, operation	281
	A. Miura, Y. Kawane, J. Tamura JAEA/J-PARC, Tokai-mura, Japan T. Miyao KEK, Ibaraki, Japan
	In the linac of the Japan Proton Accelerator Research Complex (J-PARC), the neutral hydrogen (H⁰) generation from the negative hydrogen ion (H⁻) beam is one of key issues to mitigate the beam loss. In order to diagnose the H⁰ particles, we installed the bump magnets to make a chicane orbit of the H⁻ beam. To evaluate the horizontal shifts of the beam orbit, a beam position monitor (BPM) is fabricated. The BPM measures the shift-positions with various driving currents of the bump magnets. We employed the WSM to measure the H⁻ beam profile. It also help us to compare the shift-positions measured by BPM. In this paper, the design and the performance of the BPM is described. In addition, we describe how to compare the shift position.
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MOPAB074	Low Intensity Electron Beam Controlling and Monitoring	electron, detector, controls, experiment	292
	L. Yu, Y. Li, Y.F. Sui, J.H. Yue IHEP, Beijing, People's Republic of China
	To calibrating a cosmic-ray detector, a low beam current accelerator has been built to generate ultra low intensity electron beams at Institute of High Energy Physics (IHEP). The minimum beam charge obtained was estimated to be about one electron/pulse. Beam commissioning has been carried out. The key technologies for achieving such low intensity electron beams are to control the beam using 8 movable slits and to measure the intensity of the beam using 9 movable current monitors based on scintillator. In this paper, principal of operation, instrumentation and programming of the movable slits and movable current monitors are discussed. Some results of beam commissioning are also presented.
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MOPAB088	A Differential Beam Intensity Monitoring for the CIADS LINAC	monitoring, simulation, instrumentation, pick-up	325
	Z.P. Xie Hohai University, Nanjing, People's Republic of China Y. He, R. Huang, Z.J. Wang IMP/CAS, Lanzhou, People's Republic of China
	Funding: Work supported by the National Natural Science Foundation of China (Grant No. 91026001) and the Fundamental Research Funds for the Chinese Central Universities The high power Linac places many crucial requirements on the beam diagnostics for the China initiative accelerator driven subcritical(CIADS) facility. Measuring the beam loss is essential for the purpose of machine protections for the facility. A beam position pickup based differential beam current monitoring (BPDBCM) scheme has been proposed for the MEBT section at CIADS. Discussions of the principles for the scheme and the realtionship between beam intensity measurement and the pulse length are presented. Simulations are performed and they demonstrate that the proposed system can be effective at the low enery section for the CIADS beam. This paper describes the proposed implementation that will have the capability of detecting both the instantaneous and chronicle loss in real time.
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MOPAB098	Coronagraph Based Beam Halo Monitor Development for BERLinPro	background, electron, dipole, scattering	355
	J.G. Hwang Kyungpook National University, Daegu, Republic of Korea J. Kuszynski HZB, Berlin, Germany
	For linac based high power electron machines, beam halo induced by nonlinear space charge force and scattering of trapped ions is one of the critical issues on a machine protection system. It causes additional radiation which can be a heat source on a cryogenic system as a result of uncontrolled beam losses. During the last decades, several instruments have been newly developed for measuring the beam halo distribution. The conceptual design and optimization of the coronagraph based halo monitor were performed to measure the beam halo which has ~ 10^-3 contrast to the beam core.
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MOPAB099	Design Study of Drift Tube Linac for BNCT Accelerator	DTL, quadrupole, simulation, rfq	359
	Y. Lee, S.W. Jang, E.-S. Kim Korea University Sejong Campus, Sejong, Republic of Korea B.H. Choi IBS, Daejeon, Republic of Korea D.S. Kim Dawonsys, Siheung-City, Republic of Korea Z. Li SCU, Chengdu, People's Republic of China
	A-BNCT accelerator is being developed as a proton accelerator with a high beam current of 50 mA for effective cancer therapy. Drift tube linac (DTL) with the length of 4.5 m is composed of 1 tank and 48 drift tubes (DTs). Proton beam is accelerated from 3 MeV to 10 MeV. Electromagnetic quadrupoles (EMQs) are inserted into every DT for transverse focusing. Slug tuners and post couplers (PCs) are used for accelerating field stabilization and resonant frequency tuning, respectively. The beam dynamics and engineering design for the DTL are performed for effective beam acceleration, and the design results are in detail presented.
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MOPAB120	Beam Instrumentation for the CERN LINAC4 and PSB Half Sector Test	instrumentation, laser, emittance, proton	408
	F. Roncarolo, J.C. Allica Santamaria, M. Bozzolan, C. Bracco, S. Burger, G.J. Focker, G. Guidoboni, L.K. Jensen, B. Mikulec, A. Navarro Fernandez, U. Raich, J.B. Ruiz, L. Søby, J. Tan, W. Viganò, C. Vuitton, C. Zamantzas CERN, Geneva, Switzerland T. Hofmann Royal Holloway, University of London, Surrey, United Kingdom
	The construction, installation and initial commissioning of CERN's LINAC4 was completed in 2016 with H⁻ ions successfully accelerated to its top energy of 160 MeV. The accelerator is equipped with a large number of beam diagnostic systems that are essential to monitor, control and optimize the beam parameters. A general overview of the installed systems and their functional specifications will be followed by a summary of the most relevant results. This includes transverse profile monitors (wire scanners, wire grids and a laser profile monitor), beam position and phase monitors (whose ToF measurements were essential for adjusting RF cavity parameters), beam loss monitors, beam current transformers and longitudinal beam shape monitors. This contribution will also cover the beam instrumentation for the so-called PSB Half Sector Test, which has been temporarily installed in the LINAC4 transfer line to study H⁻ stripping efficiency. At this facility it was possible to test the new H⁰/H⁻ beam current monitor, designed to monitor the stripping efficiency and an essential element of the beam interlock system when the LINAC4 is connected to the PSB in 2019.
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MOPAB149	Design of LCLS-II ATCA BPM System	network, undulator, FEL, controls	477
	A. Young, R. Claus, J.M. D'Ewart, J.C. Frisch, G. Haller, R.T. Herbst, S. L. Hoobler, U. Legat, J.J. Olsen, R. Ruckman, L. Sapozhnikov, S.R. Smith, T. Straumann, J.A. Vásquez, M. Weaver, E. Williams, C. Xu SLAC, Menlo Park, California, USA
	Funding: Work supported by U.S. Department of Energy under Contract Numbers DE-AC02-06CH11357 SLAC's LCLS-II is a next generation X-ray FEL that will use a CW 4 GeV superconducting linac with nominal bunch spacing of 1us will deliver both soft and hard x-ray FEL to users. In order to achieve the required performance, the SLAC Technical Innovation Directorate has developed a common hardware and firmware platform for beam instrumentation based on the ATCA crate format. We have designed a stripline and cavity BPM system based on this platform that is capable of measuring the beam position at full beam rate. The system will have a dynamic range between 1 pC to 300 pC. This paper will discuss the design of the BPM electronics, overall architecture and performance on LCLS-I.
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MOPIK016	Sub-Picosecond Beam Production for External Injection Into Plasma Experiments	gun, plasma, electron, simulation	531
	O. Mete Apsimon, R. Apsimon, G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom G.X. Xia UMAN, Manchester, United Kingdom
	Funding: This work has been funded by STFC. Applications of plasmas in accelerators benefit from short probe bunches comparable to plasma wavelength due to currently achievable plasma wake profiles. In plasma acceleration case, high capture efficiency within a narrow energy spectrum can be achieved when a sub-picosecond to femtosecond witness bunch injected behind the driver pulse at the high electric field region. A start-to-end simulation study was performed for parametric optimisation of an rf photoinjector to provide a short witness bunch for plasma applications in accelerators. An rf photoinjector is a laser-driven, high brightness and robust electron source that can provide stability and flexibility provided by today's advanced laser and rf technologies.
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MOPIK029	Energy Deposition and Activation Studies of the ESSnuSB Horn Station	target, proton, hadron, neutron	561
	E. Bouquerel, E. Baussan, M. Dracos IPHC, Strasbourg Cedex 2, France N. Vassilopoulos IHEP, Beijing, People's Republic of China
	Funding: This project is now supported by the COST Action CA15139 Combining forces for a novel European facility for neutrino-antineutrino symmetry-violation discovery (EuroNuNet). The ESS'SB project foresees the production of a very intense neutrino beam to enable the discovery of leptonic CP violation. In addition to the neutrinos, a copious number of muons that could be used by a future Neutrino Factory and a muon collider will also be produced at the same time. This facility will use the world's most intense pulsed spallation neutron source, the European Spallation Source (ESS) in Lund. Its LINAC is expected to be operational by 2023, producing 2 GeV protons with a power of 5 MW. The primary proton beam line completing the linear accelerator will consist of one or several accumulator rings and a proton beam switchyard. The secondary beam line producing neutrinos and muons will consist of a four-horn target station, a decay tunnel and a beam dump. To detect the produced neutrinos a far megaton scale Water Cherenkov detector will be placed at a baseline of about 500 km in one of the existing active mines in Sweden. The estimation of the energy deposited and the activation within this secondary beam line are discussed in this paper.
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MOPIK040	Value Engineering of an Accelerator Design During Construction	cavity, cryomodule, neutron, proton	592
	E. Bargalló, M. Eshraqi, M. Lindroos, S. Molloy, D.C. Plostinar, A. Sunesson ESS, Lund, Sweden F. Gerigk CERN, Geneva, Switzerland
	Value engineering is an important part of the process of designing and realising large-scale installations such as high power accelerators. This typically occurs during the later part of the design stage of the system, however such exercises may also be requested by funding bodies at later stages in order to manage project contingency. Naturally, the later this is done, the more challenging it becomes. In this paper we report on a recently concluded Value Engineering effort at the European Spallation Source. The challenges presented by the initiation of such an exercise during the construction phase are discussed. In addition, we present and discuss the various options that we examined, and indicate the philosophy and figures of merit used to narrow down these options. The final conclusion will be presented.
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MOPIK041	Commissioning of the Stripping Foil Units for the Upgrade of the PSB H⁻ Injection System	injection, controls, electron, vacuum	595
	C. Bracco, S. Burger, V. Forte, B. Goddard, G. Guidoboni, L.O. Jorat, B. Mikulec, A. Navarro Fernandez, R. Noulibos, F. Roncarolo, P. Van Trappen, W.J.M. Weterings CERN, Geneva, Switzerland
	The PSB will be extensively upgraded during the next long shutdown of the CERN accelerator complex, to double the brightness of the stored beams. The existing multi-turn injection will be replaced by a charge exchange system designed for the 160 MeV hydrogen ions provided by Linac4. Part of the injection equipment has been temporarily installed along the Linac4-to-PSB transfer line and tested with beam. This allowed to gain experience with the system, test the related diagnostics and benchmark calculations with measurements. An additional permanent stripping foil test stand is also installed right after the Linac and will be used to characterise new foils for possible future applications. The main outcomes, issues and applied or planned mitigations are presented for both installations.
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MOPIK047	Commissioning and Results of the Half-Sector Test Installation with 160 MeV H⁻ beam from Linac4	injection, operation, proton, vacuum	619
	B. Mikulec, D. Aguglia, J.C. Allica Santamaria, C. Baud, C. Bracco, S. Burger, G. Guidoboni, L.O. Jorat, C. Martin, A. Navarro Fernandez, R. Noulibos, F. Roncarolo, J.L. Sanchez Alvarez, J. Tan, T. Todorcevic, P. Van Trappen, W.J.M. Weterings, C. Zamantzas CERN, Geneva, Switzerland
	During the Long Shutdown 2 (LS2) at CERN in 2019/20, the Proton Synchrotron Booster (PSB) will undergo a profound upgrade in the framework of the LHC Injector Upgrade (LIU) project involving also the connection to the new Linac4 injector. The 160 MeV Linac4 H' injection entails a complete replacement of the PSB injection section, including a stripping foil system, injection chicane, an H⁰/H' dump and novel beam instrumentation. The equivalent of half of this new injection chicane was temporarily installed in the Linac4 transfer line to evaluate the performance of the equipment and prepare controls, interlocks and applications for the connection. Outcomes of this so-called Half-Sector Test (HST) are presented in this paper.
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MOPIK057	Strategy of Beam Tuning Implementation for the SARAF MEBT and SC Linac	solenoid, quadrupole, focusing, simulation	652
	P.A.P. Nghiem, D. Uriot CEA/DSM/IRFU, France B. Dalena, J. Dumas, N. Pichoff CEA/IRFU, Gif-sur-Yvette, France
	Beam dynamics of the MEBT and Superconducting Linac in the SARAF accelerator are being finalized. A strategy for beam tuning implementation is applied to this section, leading to specifying the complete set of error tolerances / beam measurements / correctors. A systematic and precise methodology in several steps is applied, leading to fairly distributing the error budget, from which correction schemes are studied, allowing to determine the necessary beam measurements and correctors.
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MOPIK058	Beam Dynamic Studies for the SARAF MEBT and SC Linac	quadrupole, cavity, rfq, simulation	655
	J. Dumas, N. Pichoff, D. Uriot CEA/IRFU, Gif-sur-Yvette, France P.A.P. Nghiem CEA/DSM/IRFU, France
	The SARAF MEBT and Super Conducting Linac (SCL) transport and accelerate deuterons or protons from the RFQ to the final energy. In this report, beam dynamics studies for this section are described. A rational distribution of the different roles of the MEBT leads to defining its necessary quadrupole/rebuncher composition. This allows easy beam re-tuning following changes from the RFQ or the SC Linac. After observing evidences of beam losses mainly due to phase unhooking, efforts have been dedicated to enlarge the SCL longitudinal acceptance. A combination of cavity field phases is found so that the required final beam energy is also fulfilled.
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MOPIK068	Beam Dynamics Design Parameters for KONUS Lattices	lattice, acceleration, cavity, emittance	683
	R. Tiede, H. Hähnel, U. Ratzinger IAP, Frankfurt am Main, Germany
	The 'Combined Zero-Degree Structure' ('Kombinierte Null Grad Struktur - KONUS') beam dynamics concept has been successfully applied on several linacs, some of them in routine operation since decades. However, the KONUS lattice parameters optimization is often done in a results-oriented approach, depending on the designers' experience. This paper focuses on the description of the longitudinal beam motion along one KONUS lattice period. A test lattice is used for demonstrating the potential of KONUS lattices with respect to stable, periodic beam motion with emittance growth rates similar to those of conventional designs. The main objective of this ongoing work is to derive more general rules for the parametrization of KONUS lattices.
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MOPIK095	Implementation Issues and First Results of the ESS Beam Current Monitor System	electronics, interface, ion-source, FPGA	745
	H. Hassanzadegan, M.D. Donna, A. Jansson, H. Kocevar, T.J. Shea ESS, Lund, Sweden M. Werner DESY, Hamburg, Germany
	The BCM system of the European Spallation Source needs to measure several beam parameters including pulse profile, charge, current, pulse width and repetition frequency. Moreover, it will measure differential beam currents using several ACCT pairs along the linac. This is particularly important at low beam energies where BLMs cannot be used for measuring beam losses. Due to the ESS-specific requirements, the BCM software and firmware will be customized. Also, parts of the electronics may need to be customized to be consistent with the ESS standard electronics platform, hence facilitate maintenance and maximize synergy with other systems. Technical challenges include maintaining signal integrity and a fast response despite large variations in the sensor cable length and ambient temperature, as well as minimizing the effect of the ground voltage fluctuations. This paper gives a general overview of the design and focuses on a few technical issues that are particularly important for satisfying the performance requirements. Also, BCM test results in laboratory conditions as well as preliminary results with the ESS ion source will be presented.
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MOPIK115	A Design for 10 GeV, High Peak-Current, Tightly Focused Electron Beams at FACET-II	emittance, electron, simulation, acceleration	807
	G.R. White SLAC, Menlo Park, California, USA
	Funding: This work was sponsored by the Department of Energy under Contract Number: DE-AC02-76SF00515 FACET-II will be a new test facility, starting construction in 2018 within the main SLAC Linac. Its purpose is to build on the decades-long experience developed conducting accelerator R&D at SLAC in the areas of advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. The design consists of a 135-MeV high-brightness photo-injector constructed in an off-axis injection line in Sector 10 of the SLAC Linac, two new 4-bend chicane bunch compressors installed in Sectors 11 and 14, with a third compression stage provided by the existing FACET W Chicane in Sector 20. We develop a design to deliver peak currents more than 160 kA to the Sector 20 interaction region at 10 GeV, with 10 'm-rad emittances at 2 nC bunch charge and 1.4 % rms energy spread. The Sector 20 bunch compressor is re-designed for maximum peak current throughput and minimal emittance degradation via CSR, and the FACET-II compression scheme is optimized. We present 6D start-end beam tracking simulations using Lucretia including ISR, CSR, wakefields and space charge effects.
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MOPIK117	On the Computation of Phase and Energy Gain for a Thin-Lens RF Gap Using a General Field Profile	simulation, factory, acceleration, cavity	810
	C.K. Allen ORNL, Oak Ridge, Tennessee, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract number DE-AC05-00OR22725. The thin-lens representation for an RF accelerating gap has been well developed and is documented by Lapostolle [5], Weiss [6], Wangler [14], and others [9], [10]. These models assume that the axial electric field is both centered and symmetric so it has a cosine expansion. Presented here is a model that considers general axial fields. Both the cosine and sine transit time factors are required plus their Hilbert transforms. The combination yields a complex Hamiltonian rotating in the complex plane with the synchronous phase. The phase and energy gains are computed in the pre-gap and post-gap regions then aligned with asymptotic values of wave number. Derivations are outlined, examples are shown, and simulations presented.
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MOPIK118	Model Based Optics Studies in the MEBT Section of SNS	emittance, lattice, simulation, rfq	814
	A.P. Shishlo, A.V. Aleksandrov, A.P. Zhukov ORNL, Oak Ridge, Tennessee, USA Y. Liu KEK/JAEA, Ibaraki-Ken, Japan
	Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC0500OR22725 with the U.S. Department of Energy. The paper presents the beam dynamics studies for the Medium Energy Beam Transport (MEBT) section of the Spallation Neutron Source (SNS) accelerator. The analysis of measurements is based on the PyORBIT linac model. The diagnostics data includes wire scanners' profiles, slit-harp and slit-slit transverse emittances, MEBT re-bunchers calibration data, and bunch length measurements. The MEBT is a matching section between RFQ and a Drift Tube Linac (DTL). It is also a place for beam halo scraping which helps to reduce beam loss in downstream linac sections. The linac simulation code was benchmarked against the diagnostics data.
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MOPVA005	Status of the Berlin Energy Recovery Linac Project BERLinPro	gun, SRF, booster, cavity	855
	M. Abo-Bakr, W. Anders, K.B. Bürkmann-Gehrlein, A.B. Büchel, P. Echevarria, A. Frahm, H.-W. Glock, F. Glöckner, F. Göbel, B.D.S. Hall, S. Heling, H.-G. Hoberg, A. Jankowiak, C. Kalus, T. Kamps, G. Klemz, J. Knedel, J. Knobloch, J. Kolbe, G. Kourkafas, J. Kühn, B.C. Kuske, J. Kuszynski, D. Malyutin, A.N. Matveenko, M. McAteer, A. Meseck, C.J. Metzger-Kraus, R. Müller, A. Neumann, N. Ohm, K. Ott, E. Panofski, F. Pflocksch, J. Rahn, M. Schmeißer, O. Schüler, M. Schuster, J. Ullrich, A. Ushakov, J. Völker HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association. The Helmholtz-Zentrum Berlin is constructing the Energy Recovery Linac Prototype BERLinPro, a demonstration facility for the science and technology of ERLs for future light source applications. BERLinPro is designed to accelerate a high current (100 mA, 50 MeV), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. We report on the project status. This includes the completion of the building and the installation of the first accelerator components as well as the assembly of the SRF gun and GunLab beam diagnostics, which are now ready for commissioning.
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MOPVA008	Commissioning Considerations for BERLinPro	laser, diagnostics, gun, target	862
	M. McAteer, M. Abo-Bakr, T. Kamps, G. Klemz, J. Kuszynski HZB, Berlin, Germany I. Will MBI, Berlin, Germany
	BERLinPro is an energy recovery linac project whose goal is to establish the accelerator physics knowledge and technology needed to produce 50 MeV beams with high current, low normalized emittance, and low losses. The machine will be commissioned in phases beginning in 2018, and extensive planning is underway for start-up of the machine and to prepare for measurements to verify the achievement of target beam parameters. This paper outlines the planned phases for the commissioning of the machine, details the operational modes, and gives an overview of the diagnostics available for beam-based measurements to verify the achievement of performance goals.
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MOPVA012	The Dedicated Accelerator R&D Facility Sinbad at DESY	electron, laser, experiment, acceleration	869
	U. Dorda, R.W. Aßmann, K. Galaydych, W. Kuropka, B. Marchetti, D. Marx, F. Mayet, G. Vashchenko, T. Vinatier, P.A. Walker, J. Zhu DESY, Hamburg, Germany A. Fallahi, F.X. Kärtner, N.H. Matlis CFEL, Hamburg, Germany
	We present an overview of the dedicated R\&D facility SINBAD which is currently under construction at DESY. The facility will host multiple independent experiments on the acceleration of ultra-short electron bunches and advanced acceleration schemes. In its initial phase, SINBAD will host two experiments: AXSIS and ARES. The AXSIS collaboration aims to accelerate fs-electron bunches to 15 MeV in a THz driven dielectric structure and subsequently create X-rays by inverse Compton scattering. The first stage of the ARES experiment is to set up a 100 MeV S-band electron linac to produce ultra-short electron bunches with excellent beam arrival time stability. Once this is achieved, the electrons will be ideally suited to be injected into experiments for testing advanced accelerator concepts e.g. DLA experiments in the context of the ACHIP collaboration. In the long term, external injection into a laser driven plasma acceleration stage is targeted as well.
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MOPVA013	Application of Non-Isochronous Beam Dynamics in ERLs for Improving Energy Spread and Beam Stability	electron, acceleration, operation, recirculation	873
	F. Hug IKP, Mainz, Germany
	Funding: Work supported by DFG through the PRISMA cluster of excellence EXC 1098/2014 and Research Training Group GRK 2128 Non-isochronous recirculation is the common operation mode for synchrotrons or microtrons. In such a non-isochronous recirculation scheme the recirculation paths provide a non-zero longitudinal dispersion while the accelerating field is operated at a certain phase off-crest with respect to the maximum. In few turn linacs like ERLs and in microtrons non-isochronous beam dynamics can be used to reduce the energy spread by cancelling out any rf-jitters coming from the linac cavities. To do so the longitudinal phase advance needs to be tuned to a half-integer number of oscillations in longitudinal phase space. Then the total energy spread after main linac acceleration conserves the value at injection. In addition to the improved energy spread the beam stability of few-turn recirculators can be increased as well using such a system. Such concept provides an inherent beam stability and has been introduced many years ago [] and proven to work successfully in a few-turn recirculator already []. We will present beam dynamics calculations for the application of nonisochronous beam dynamics in single- and multi-turn energy recovery linacs at different longitudinal working points. [] H. Herminghaus, NIM. A 314 (1992) 209. [**] F. Hug et al., Proc. of LINAC '12 (2012) 531.
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MOPVA014	Injector Linac Stability Requirements for High Precision Experiments at MESA	experiment, electron, operation, acceleration	876
	F. Hug, R.G. Heine IKP, Mainz, Germany
	Funding: Work supported by DFG through the PRISMA cluster of excellence EXC 1098/2014 and Research Training Group GRK 2128 MESA is a recirculating superconducting accelerator under construction at Johannes Gutenberg-Universität Mainz. It will be used for high precision particle physics experiments in two different operation modes: external beam (EB) mode and energy recovery (ERL) mode. The operating beam current and energy in EB mode is 0.15 mA with polarized electrons at 155 MeV. In ERL mode an unpolarized beam of 1 mA at 10⁵ MeV will be available. In a later construction stage of MESA the beam current in ERL-mode shall be upgraded to 10 mA. In order to achieve high beam stability and low energy spread in recirculating operation the acceleration in the main linac sections will be done on edge of the accelerating field while the return arcs provide longitudinal dispersion. On certain longitudinal working points this can result in a setting where rf jitters from main linac do not contribute to the resulting energy spread of the final beam at all [,]. Then the resulting energy spread is only determined by the energy spread provided by the inector linac. Within this contribution we will investigate the requirements on the stability of the MESA injector linac MAMBO for achieving the experimental goals. [] H. Herminghaus, NIM. A 314 (1992) 209. [**] F. Hug et al., Proc. of LINAC '12 (2012) 531.
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MOPVA016	ELI-NP GBS Status	laser, electron, gun, collimation	880
	A. Giribono, M. Marongiu, A. Mostacci, V. Pettinacci INFN-Roma, Roma, Italy S. Albergo INFN-CT, Catania, Italy D. Alesini, M. Bellaveglia, B. Buonomo, F. Cioeta, E. Di Pasquale, G. Di Pirro, A. Esposito, A. Falone, G. Franzini, O. Frasciello, A. Gallo, S. Guiducci, S. Incremona, F. Iungo, V.L. Lollo, L. Pellegrino, L. Piersanti, S. Pioli, R. Ricci, U. Rotundo, L. Sabbatini, A. Stella, S. Tomassini, C. Vaccarezza, A. Variola INFN/LNF, Frascati (Roma), Italy A. Bacci, C. Curatolo, I. Drebot, V. Petrillo, A.R. Rossi, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy N. Bliss, C. Hill STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom G. Campogiani Rome University La Sapienza, Roma, Italy P. Cardarelli, M. Gambaccini INFN-Ferrara, Ferrara, Italy F. Cardelli, A. Mostacci, L. Palumbo, A. Vannozzi University of Rome La Sapienza, Rome, Italy F. Cardelli, L. Palumbo INFN-Roma1, Rome, Italy K. Cassou, K. Dupraz, A. Martens, C.F. Ndiaye, Z.F. Zomer LAL, Orsay, France G. D'Auria Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy L. Sabato U. Sannio, Benevento, Italy M. Veltri INFN-FI, Sesto Fiorentino, Italy
	New generation of Compton sources are developing in different countries to take advantage of the photon energy amplification given by the Compton backscattering effect. In this framework the Eurogammas international collaboration is producing a very high brilliance gamma source for the Nuclear Pillar of the Exterme Light Infrastructure program (ELI). At present there is a lot of effort in the mass production of all the components and in the developments and tests of the different high technology devices that will operate in the gammas beam source, like the optical recirculator and the high gradient - high average current warm C band accelerating sections. In this paper we will provide a general overview of the GBS status and of the perspectives for the future integration phase.
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MOPVA017	Electrostatic Pickup in the CNAO Injection Line	ion, pick-up, detector, proton	884
	A. Parravicini, G.M.A. Calvi, E. Rojatti, C. Viviani CNAO Foundation, Pavia, Italy
	The paper concerns the electrostatic pickup (PUB) installed in the injection line of the CNAO, the Italian facility for Oncological Hadrontherapy. The PUB has been designed with the purpose of having a continuous and non-interceptive measurement of the beam transverse position short upstream the injection in the synchrotron. Detector commissioning has not been immediate since a number of primary ions and secondary electrons fall on the PUB electrodes in many configurations, resulting in a significantly distorted signal. After the identification, and consequent rejection, of a few circumstances where the PUB cannot work properly, the commissioning proceeded on a twofold way, designing a mechanical shield to stop ions before hitting the electrodes and developing an advanced data-analysis algorithm to go beyond the signal distortion. The use of the new algorithm was sufficient to make the PUB successfully working and, after a proper calibration with upstream and downstream profile monitors, the PUB started to provide the expected results. The PUB is working as a watch-dog since January 2016. Details on the data-analysis algorithm and first year measurements are discussed in the paper.
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MOPVA019	60 pC Bunch Charge Operation of the Compact ERL at KEK	operation, emittance, laser, cavity	890
	T. Miyajima, K. Harada, Y. Honda, E. Kako, R. Kato, T. Miura, N. Nakamura, T. Obina, M. Shimada, R. Takai, K. Umemori, M. Yamamoto KEK, Ibaraki, Japan R. Hajima, R. Nagai QST, Tokai, Japan T. Hotei Sokendai, Ibaraki, Japan N. Nishimori Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	The compact ERL (cERL) at KEK was operated in March 2017 to demonstrate generation, acceleration and transportation of the target bunch charge of 60 pC without energy recovery. However, the maximum bunch charge was limited to 40 pC due to the limitation of the excitation laser power. For the bunch charge of 40 pC, the bunch length and the normalized emittance were measured in the injector diagnostic line. The results of the bunch length measurement gave good agreement with the values that had been obtained by model simulation. The measured normalized rms emittances for 40 pC were 0.9 to 2.4 mm mrad, and they were lager than the design value of 0.6 mm mrad. To achieve the design emittance, we have studied the source of the emittance growth for the bunch charge of 40 pC.
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MOPVA020	S2E Simulation of an ERL-Based High-Power EUV-FEL Source for Lithography	FEL, electron, simulation, injection	894
	N. Nakamura, R. Kato, T. Miyajima, M. Shimada KEK, Ibaraki, Japan R. Hajima QST, Tokai, Japan T. Hotei Sokendai, Ibaraki, Japan
	An energy recovery linac(ERL)-based free electron laser(FEL) is a possible candidate of a high-power EUV source for lithography. The ERL can provide a high-current and high-quality electron beam for the high-power FEL and also greatly reduce the dumped beam power and activation compared to ordinary linacs. An ERL-based EUV-FEL source has been designed using available technologies and resources. For this design, we perform Start-to-End(S2E) simulation from the electron gun to the exit of the decelerating main linac to track the electron beam parameters and to evaluate the FEL performance. The electron bunches from the injector are off-crest accelerated to 800 MeV and compressed in the 1st arc and/or chicane to obtain a high-peak current for high FEL output. After the undulator section for SASE FEL, they are decompressed in the 2nd arc and then decelerated in the main linac to optimize the energy spread or the energy recovery efficiency. This paper will present the S2E simulation for the designed EUV-FEL source. N. Nakamura et al., Proc. of ERL2015, Stony Brook, NY, USA, pp.4-9.
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MOPVA033	A Compact Thermionic RF Injector with RF Bunch Compression fed by a Quadrupole-Free Mode Launcher	gun, cathode, electron, undulator	924
	F. Toufexis, V.A. Dolgashev, C. Limborg-Deprey, S.G. Tantawi SLAC, Menlo Park, California, USA
	Funding: This project was funded by U.S. Department of Energy under Contract No. DE-AC02-76SF00515, and the National Science Foundation under Contract No. PHY-1415437. We present a design for a compact X-Band RF thermionic injector consisting of two iris-loaded accelerator structures. Both structures are fed by a single quadrupole-free TM01 mode launcher. In the first structure the electron bunches are extracted from a thermionic cathode. The second structure creates an energy chirp in the bunch for its further ballistic compression. This injector can produce short electron bunches without the need for a magnetic bunch compressor. We are developing this injector as part of a linac-based 91.392 GHz RF power source, which further comprises a booster linac and a mm-wave decelerator structure that extracts 91.392 GHz RF power from the electron beam. This source will be used to power a short-period RF undulator with 1.75 mm period. F. Toufexis and S.G. Tantawi, A 1.75 mm Period RF-Driven Undulator, these proceedings.
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MOPVA037	Development and Commissioning of the Doppler-Shift Unit for the Measurement of the Ion Species Fractions and Beam Energy of the ESS Proton Source	proton, coupling, software, optics	936
	C.A. Thomas, T.J. Shea ESS, Lund, Sweden J. Fils GSI, Darmstadt, Germany Y. Lussignol, P. Mattei CEA/DSM/IRFU, France Ø. Midttun University of Bergen, Bergen, Norway L. Neri INFN/LNS, Catania, Italy F. Senée, O. Tuske CEA/IRFU, Gif-sur-Yvette, France
	ESS proton source is in going to be soon delivered to the ESS project. In order to qualify the source, a series of beam instrumentation diagnostics have been designed and produced. In particular, a specific spectrograph dedicated to the fraction species measurement is currently commissioned. This instrument not only is capable of measuring the fraction species produced by the source, but also it can measure their energy and energy spread, the mass of the different species, and additional spectral rays coming from the gas species in presence in the vacuum chamber. We present in this paper the commissioning of this instrument, the Doppler Shift unit, dedicated to the measurement of the fraction species.
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MOPVA038	Manufacturing Status of the IFMIF LIPAc SRF Linac	cryomodule, vacuum, SRF, cavity	939
	N. Bazin, P. Carbonnier, P. Contrepois, J. Plouin, B. Renard CEA/DSM/IRFU, France C. Boulch, A. Bruniquel, J.K. Chambrillon, G. Devanz, P. Hardy, H. Jenhani, N. N'Doye, O. Piquet, A. Riquelme, D. Roudier CEA/DRF/IRFU, Gif-sur-Yvette, France P. Charon, S. Chel, G. Disset, J. Relland CEA/IRFU, Gif-sur-Yvette, France D. Regidor, F. Toral CIEMAT, Madrid, Spain
	This paper gives the fabrication status of the IFMIF cryomodule. This cryomodule will be part of the Linear IFMIF Prototype Accelerator (LIPAc) whose construction is ongoing at Rokkasho, Japan. It is a full scale of one of the IFMIF accelerator, from the injector to the first cryomodule. The cryomodule contains all the necessary equipment to transport and accelerate a 125 mA deuteron beam from an input energy of 5 MeV up to the output energy of 9 MeV. It consists of a horizontal vacuum tank of around 6 m long, 3 m high and 2.0 m wide, which includes 8 superconducting HWRs for beam acceleration, working at 175 MHz and at 4.45 K, 8 Power Couplers to provide RF power to cavities up to 70 kW CW in LIPAc case and 200 kW CW in IFMIF case, and 8 Solenoid Packages as focusing elements.
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MOPVA041	Vertical Test Results on ESS Medium and High Beta Elliptical Cavity Prototypes Equipped with Helium Tank	cavity, radiation, cryomodule, background	948
	E. Cenni CEA/IRFU, Gif-sur-Yvette, France P. Bosland, G. Devanz, F. Éozénou, X. Hanus, L. Maurice, F. Peauger, J. Plouin, D. Roudier, C. Servouin CEA/DSM/IRFU, France G. Costanza Lund University, Lund, Sweden C. Darve ESS, Lund, Sweden
	The ESS elliptical superconducting Linac consists of two types of 704.42 MHz cavities, medium and high beta, to accelerate the beam from 216 MeV (spoke cavity Linac) up to the final energy at 2 GeV. The last Linac optimization, called Optimus+, has been carried out taking into account the limitations of SRF cavity performance (field emission). The medium and high-beta parts of the Linac are composed of 36 and 84 elliptical cavities, with geometrical beta values of 0.67 and 0.86 respectively. This work presents the latest vertical test results on ESS medium and high beta elliptical cavity prototypes equipped with helium tank. We describe the cavity preparation procedure from buffer chemical polishing to vertical test.
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MOPVA046	120kW RF Power Input Couplers for BERLinPro	booster, cavity, coupling, SRF	960
	B.D.S. Hall, V. Dürr, F. Göbel, J. Knobloch, A. Neumann HZB, Berlin, Germany
	The 50-MeV, 100-mA energy-recovery-linac (ERL) demonstration facility BERLinPro is currently undergoing construction at HZB. The high power injection system, that will deliver a beam at 6.5MeV, is split into a 1.4 cell SRF Photo injector and three Cornell-style 2-cell boosters. The injector and two of the booster cavities will provide about 2MeV each and must handle up to 220 kW of beam loading. New, cERL-based 115-kW high power couplers needed for the cavities' twin coupler system have begun manufacture. The design, optimization and manufacturing considerations of these couplers are presented.
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MOPVA049	First Commissioning of an SRF Photo-Injector Module for BERLinPro	cavity, cathode, SRF, solenoid	971
	A. Neumann, A. Burrill, D. Böhlick, A.B. Büchel, M. Bürger, P. Echevarria, A. Frahm, H.-W. Glock, F. Göbel, S. Heling, K. Janke, T. Kamps, S. Keckert, S. Klauke, G. Klemz, J. Knobloch, G. Kourkafas, J. Kühn, O. Kugeler, N. Ohm, E. Panofski, H. Plötz, S. Rotterdam, M. Schenk, M.A.H. Schmeißer, M. Schuster, H. Stein, Y. Tamashevich, J. Ullrich, A. Ushakov, J. Völker HZB, Berlin, Germany A. Matheisen, M. Schmökel DESY, Hamburg, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association. Helmholtz-Zentrum Berlin (HZB) is currently building an high average current superconducting ERL to demonstrate ERL operation with low normalized beam emittance of 1 mm·mrad at 100mA and short pulses of about 2 ps. For the injector section a series of SRF photoinjector cavities is being developed. The medium power prototype presented here features a 1.4 x λ/2 cell SRF cavity with a normal-conducting, high quantum efficiency CsK2Sb cathode, implementing a modified HZDR-style cathode insert. This injector potentially allows for 6 mA beam current at up to 3.5 MeV kinetic energy. In this contribution, the first RF commissioning results of the photo-injector module will be presented and compared to the level of performance during the cavity production and string assembly process.
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MOPVA054	High Power RF Coupler for the CW-Linac Demonstrator at GSI	cavity, Windows, simulation, ion	990
	M. Heilmann, W.A. Barth, S. Yaramyshev GSI, Darmstadt, Germany M. Amberg, M. Basten, R. Blank, M. Busch, F.D. Dziuba, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany K. Aulenbacher IKP, Mainz, Germany K. Aulenbacher, W.A. Barth, V. Gettmann, M. Miski-Oglu HIM, Mainz, Germany W.A. Barth, S. Yaramyshev MEPhI, Moscow, Russia
	The planned super-heavy element (SHE) research project investigates heavy ions near the coulomb barrier in future experiments. A superconducting (sc) continuous wave (cw) CH-Linac Demonstrator was developed and installed behind the High Charge State Injector (HLI) at GSI Darmstadt, Germany. In future the advanced cw-LINAC setup, with several CH-cavities, will accelerates the heavy ion beam from HLI with an energy of 1.4 MeV/u up to 3.5 - 7.3 MeV/u. The RF power of several kW will be coupled capacitively into the CH-cavities with minimal reflection at an operation frequency of 217 MHz. Two ceramic windows (Al2O3) are installed inside the RF coupler, to reduce the premature contamination of the cavity and as an additional vacuum barrier. The CH-cavity will be operated at cryogenic temperature (4 K) and will be increased to room temperature along the RF coupler. The optimally adapted RF coupler design, providing minimal RF losses and simultaneously maximal performance, was optimized by electromagnetic simulations. An RF coupler design with a reflection-free RF adaptor as well as the temperature distribution along the coupler will be presented.
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MOPVA058	Commissioning and Operation Experience of the 3.9 GHz System in the EXFEL Linac	cavity, operation, LLRF, klystron	999
	C.G. Maiano, J. Branlard, M. Hüning, M. Omet, P. Pierini, E. Vogel DESY, Hamburg, Germany A. Bosotti, R. Paparella, P. Pierini, D. Sertore INFN/LASA, Segrate (MI), Italy
	The European X-ray Free Electron Laser (EXFEL) injector linac hosts a 3.9~GHz module (AH1) for beam longitudinal phase space manipulation after the first acceleration stage, in order for the linac to deliver the high current beams with sufficiently low emittance for the production of 1 Angstrom FEL light to the experimental users. The module was technically commissioned in December 2015 and operated well above its nominal performances during the Injector Run from January to July 2016. Its operation has restarted in January 2017 with the startup of the whole facility, and the system met the design beam specifications after the bunch compression stages. A brief review of the commissioning and first operation experience of the RF system are presented here.
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MOPVA066	Limits for the Operation of the European XFEL 3.9 GHz System in CW Mode	cavity, operation, cryomodule, laser	1023
	P. Pierini, A. Bosotti, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy J. Branlard, D. Kostin, C.G. Maiano, W.-D. Möller, P. Pierini, D. Reschke, J.K. Sekutowicz, E. Vogel DESY, Hamburg, Germany
	Future upgrades of the European XFEL (EXFEL) facility may require driving the linac at higher duty factor, possibly extending to CW mode at reduced gradients. A preliminary analysis for the accelerator modules has been presented in the EXFEL TDR, but no precise assessment has been performed so far for the present 3.9 GHz system design. By making use of data collected during the commissioning and operation phase of the EXFEL injector system, we discuss here an estimate for the limits of CW operation of the present system and a plan for its possible experimental verification with existing available cavities and the EXFEL spare module.
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MOPVA074	Fabrication of Superconducting QWR at MHI-MS	cavity, SRF, superconducting-RF, niobium	1037
	N. Shigeoka, H. Hara, A. Miyamoto, K. Sennyu, T. Yanagisawa MHI-MS, Kobe, Japan O. Kamigaito, K. Ozeki, N. Sakamoto, K. Suda, Y. Watanabe, K. Yamada RIKEN Nishina Center, Wako, Japan
	Mitsubishi Heavy Industries Mechatronics Systems, Ltd. (MHI-MS), a subsidiary campany of MHI, took over MHI's accelerator business on October 1, 2015, and has been developing the business. MHI-MS is manufacturing the prototype Superconducting QWR for RIKEN Superconducting linac project. MHI-MS has dedicated surface treatment facilities for superconducting cavities, the QWR will be treated using this facilities. In this presentation, recent progress will be reported.
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MOPVA087	Low Betta Superconducting Cavity for the New Injector Linac for Nuclotron-NICA	cavity, simulation, multipactoring, accelerating-gradient	1058
	M. Gusarova, T.A. Bakhareva, M.V. Lalayan, S.V. Matsievskiy, N.P. Sobenin, D.V. Surkov, K.V. Taletskiy, V. Zvyagintsev MEPhI, Moscow, Russia A.A. Bakinowskaya, V.S. Petrakovsky, A.I. Pokrovsky, D.A. Shparla Physical-Technical Institute of the National Academy of Sciences of Belarus, Minsk, Belarus A.V. Butenko, G.V. Trubnikov JINR/VBLHEP, Dubna, Moscow region, Russia V. Zvyagintsev TRIUMF, Vancouver, Canada
	The results of the RF, mechanical and multipactor discharge simulations of the 162 MHz quarter wave resonator (QWR) for New Superconducting Injector Linac for Nuclotron-NICA are presented. Cavity design in conjunction with manufacturing features is discussed.
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MOPVA088	Medium Betta Superconducting Cavity for the New Injector Linac for Nuclotron-NICA	cavity, simulation, multipactoring, accelerating-gradient	1061
	M. Gusarova, M.V. Lalayan, N.P. Sobenin, D.V. Surkov, K.V. Taletskiy MEPhI, Moscow, Russia A.A. Bakinowskaya, V.S. Petrakovsky, A.I. Pokrovsky, D.A. Shparla Physical-Technical Institute of the National Academy of Sciences of Belarus, Minsk, Belarus A.V. Butenko, G.V. Trubnikov JINR/VBLHEP, Dubna, Moscow region, Russia
	The results of the electrodynamical and multipactor discharge simulations of the medium betta superconducting cavity for New Superconducting Injector Linac for Nuclotron-NICA are presented. Different designs of CH and Spoke cavities are compared and the optimal one is chosen.
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MOPVA090	ESS Superconducting RF Collaboration	cryomodule, cavity, SRF, proton	1068
	C. Darve, H. Danared, N. Elias, N.F. Hakansson, M. Lindroos, C.G. Maiano, F. Schlander ESS, Lund, Sweden F. Ardellier, P. Bosland CEA/DRF/IRFU, Gif-sur-Yvette, France S. Bousson, G. Olry IPN, Orsay, France M. Ellis, A.E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom L. Hermansson, R.J.M.Y. Ruber Uppsala University, Uppsala, Sweden P. Michelato, D. Sertore INFN/LASA, Segrate (MI), Italy
	The European Spallation Source (ESS) project is a neutron-scattering facility, currently under construction by a partnership of at least 17 European countries, with Sweden and Denmark as host nations. The ESS was designated a European Research Infrastructure Consortium, or ERIC, by the European Commission in October of 2015. Scientists and engineers from 50 different countries are members of the workforce in Lund who participate in the design and construction of the European Spallation Source. In complement to the local workforce, the superconducting RF linear accelerator is being prototyped and will be constructed based on a collaboration with European institutions: CEA-Saclay, CNRS-IPN Orsay, INFN-LASA, STFC-Daresbury, Uppsala and Lund Universities. After a description of the ESS collaborative project and its in-kind model for the SRF linac, this article will introduce the linac component first results.
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MOPVA106	Experimental Studies of Asymmetric Dual Axis Cavity for Energy Recovery LINAC	cavity, electron, luminosity, radiation	1105
	I.V. Konoplev, A.J. Lancaster, K. Metodiev, A. Seryi JAI, Oxford, United Kingdom R. Ainsworth Fermilab, Batavia, Illinois, USA G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	Funding: The Leverhulme Trust via International Network Grant (IN-2015-012). Increasing the beam charge and repetition rate leads to appearance of beam break-up instabilities in conventional ERLs. At this stage the highest current, from the SRF ERL, is around 300mA. A single turn, dual axis, compact Asymmetric Energy Recovery LINAC (AERL) was proposed. The concept assumes the use of electron beams with energies up to 300 MeV and peak currents >1A, enabling the generation of high flux EUV/X-rays and THz radiation using conventional approaches. System allows beam to be transported through each stage i.e. the acceleration, interaction and deceleration only once partially removing the feedback thus increasing the instability start current. This further improved by tuning the individual cells allowing only operating mode to be uniform inside the cavity. We present the studies of 7 cells, aluminium alloy prototype of the cavity and discuss the experimental results. We show that HOMs excited on the different axis have different R/Q factors and show the field structures of operating mode and HOMs. The experimental results observed are in good agreement with theoretical predictions and the full scale copper prototype is demonstrated.
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MOPVA115	Status and Challenges of Vertical Electro-Polishing R&D at Cornell	cathode, cavity, niobium, SRF	1115
	F. Furuta, M. Ge, T. Gruber, D.L. Hall, J.J. Kaufman, M. Liepe, R.D. Porter, J. Sears Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi MGH, Hyogo-ken, Japan T.D. Hall, M.E. Inman, R. Radhakrishnan, S.T. Snyder, E.J. Taylor Faraday Technology, Inc., Clayton, Ohio, USA H. Hayano, S. Kato, T. Saeki KEK, Ibaraki, Japan
	Advanced Vertical Electro-Polishing (VEP) R&D for SRF Niobium cavities continues at Cornell's SRF group. One focus of this work is new EP cathode development in collaboration with KEK and Marui Galvanizing Co. Ltd (Marui) in Japan, and another focus is on HF free or acid free VEP protocols in collaboration with Faraday Technology Inc. The outcomes of these activities could be a significant cost reduction and an environmentally-friendlier VEP, which would be a breakthrough for future large scale EP applications on SRF cavities. Here we give a status update and report latest results from these R&D activities.
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MOPVA122	Microphonics Studies of the CBETA Linac Cryomodules	cavity, cryomodule, operation, SRF	1138
	N. Banerjee, J. Dobbins, F. Furuta, D.L. Hall, G.H. Hoffstaetter, M. Liepe, P. Quigley, E.N. Smith, V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work was performed through the support of NYSERDA (New York State Energy Research and Development Agency). The Cornell BNL ERL Test Accelerator (CBETA) incorporates two SRF linacs; one for its injector and another for the energy recovery loop. Microphonics in both the cryomodules play a crucial role in determining the energy stability of the electron beam in high current operation. We have measured vibrations and frequency detuning of the SRF cavities and determined that the cryogenic system is the major source of microphonics in both cryomodules. In this paper we discuss these measurements and demonstrate an Active Microphonics Compensation system implemented using fast piezo-electric tuners which we incorporated in our Low Level RF control system to be used in routine operation.
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MOPVA124	Effectiveness of Chemical Treatments for Reducing the Surface Roughness of Nb3Sn	niobium, SRF, klystron, cavity	1145
	R.D. Porter, F. Furuta, D.L. Hall, M. Liepe, J.T. Maniscalco Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: DOE DE-SC008431, NSF-PHY 1549132, NSF DMR-1120296 Current Niobium-3 Tin (Nb3Sn) superconducting radio-frequency (SRF) accelerator cavities have rougher surfaces than conventional electropolished Niobium accelerator cavities. The surface roughness can cause enhancement of the surface magnetic field, pushing it beyond the critical field. If this occurs over a large enough area it can cause the cavity to quench. The surface roughness may cause other effects that negatively impact cavity quality factor (Q) performance. Reducing surface roughness of Nb3Sn cavities may be necessary to achieve higher gradient with high Q. Current chemical treatments for reducing the surface roughness of Niobium are challenging for Nb3Sn: the Nb3Sn layer is only ~2 um thick while it is difficult to remove less than 1 mu uniformly with most chemical treatments. This paper presents measurements of the surface roughness before and after Buffered Chemical Polish, Electropolishing and oxipolishing.
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MOPVA127	Vertical Test Results for the LCLS-II 1.3 GHz First Article Cavities	cavity, cryomodule, SRF, FEL	1152
	A. Burrill, D. Gonnella, M.C. Ross SLAC, Menlo Park, California, USA G.K. Davis, A.D. Palczewski, L. Zhao JLab, Newport News, Virginia, USA A. Grassellino, O.S. Melnychuk Fermilab, Batavia, Illinois, USA
	The LCLS-II project requires 35 1.3 GHz cryomodules to be installed in the accelerator in order to deliver a 4 GeV electron beam to the undulators hall. These 35 cryomodules will consist of 8 1.3 GHz TESLA style SRF cavities, a design most recently used for the XFEL project in Hamburg, Germany. The cavity design has remained largely unchanged, but the cavity treatment has been modified to utilize the nitrogen doping process to allow for Quality factors in excess of 3x10¹⁰ at 16 MV/m, the designed operating gradient of the cavities in the CM. Two industrialized vendors are producing most of the SRF cavities for these cryomodules; and the performance of the first article cavities, 16 from each vendor, will be reported on in this paper.
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MOPVA131	Status of the LCLS-II Accelerating Cavity Production	cavity, status, controls, target	1164
	F. Marhauser, E. Daly, J.A. Fitzpatrick, A.D. Palczewski, J.P. Preble, K.M. Wilson JLab, Newport News, Virginia, USA A. Burrill, D. Gonnella SLAC, Menlo Park, California, USA C.J. Grimm Fermilab, Batavia, Illinois, USA
	Funding: Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 with supplemental funding from the LCLS-II Project U.S. DOE Contract No. DE-AC02-76SF00515. Cavity serial production for the LCLS-II 4 GeV CM SRF linac has started. A quantity of 266 accelerating cavities has been ordered from two industrial vendors. Jefferson Laboratory leads the cavity procurement activities for the project and has successfully transferred the Nitrogen-Doping process to the industrial partners in the initial phase, which is now being applied for the production cavities. We report on the results from vendor qualification and the status of the cavity production for LCLS-II.
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MOPVA133	Optimization of the RF Cavity Heat Load and Trip Rates for CEBAF at 12 GeV	cavity, operation, electron, SRF	1170
	H. Zhang, A. Freyberger, G.A. Krafft, Y. Roblin JLab, Newport News, Virginia, USA B. Terzić ODU, Norfolk, Virginia, USA
	Funding: Work supported by the Department of Energy under Contract No. DE-AC05-06OR23177 The Continuous Electron Beam Accelerator Facility at JLab has 200 RF cavities in the north linac and the south linac respectively after the 12 GeV upgrade. The purpose of this work is to simultaneously optimize the heat load and the trip rate for the cavities and to reconstruct the pareto-optimal front in a timely manner when some of the cavities are turned down. By choosing an efficient optimizer and strategically creating the initial gradients, the pareto-optimal front for no more than 15 cavities down can be re-established within 20 seconds.
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TUYA1	Linac4: From Initial Design to Final Commissioning	quadrupole, proton, emittance, DTL	1217
	A.M. Lombardi CERN, Geneva, Switzerland
	This talk reviews the design, construction, and commissioning effort of CERN's new proton linear accelerator, Linac4, which has recently been commissioned and which is presently undergoing a reliability run. Linac4 will be connected to the LHC proton injector chain during the next long LHC shut down (LS2) and will then replace the ageing Linac2.
	Slides TUYA1 [30.159 MB]
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TUOBA1	Beam Commissioning Results of the CSNS Linac	DTL, rfq, cavity, quadrupole	1223
	J. Peng, Y.W. An, S. Fu, L. Huang, M.Y. Huang, Y. Li, Z.P. Li, S. Wang, S.Y. Xu, Y. Yuan IHEP, Beijing, People's Republic of China M.T. Li, Y.D. Liu CSNS, Guangdong Province, People's Republic of China
	The China Spallation Neutron Source(CSNS) accelera-tor systems is designed to deliver a 1.6GeV, 100kW pro-ton beam to a solid metal target for neutron scattering research. It consists of a 50keV H⁻ Ion Source, a 3MeV Radio Frequency Quadrupole (RFQ), an 80MeV Drift Tube Linac (DTL), and a 1.6GeV Rapid-cycling Synchro-tron (RCS). The beam commissioning has been started since April 2015. The Front End and three of the four DTL tanks have been commissioned, while the last tank and the RCS will be commissioned at the autumn this year. At the end of the DTL3, beam has been accelerated to 61MeV with nearly 100% transmission, other parame-ters such as peak current, transverse emittance and beam orbit have reached the design goal. Results and status of the beam commissioning program will be presented. This work is supported by National Natural Science Foundation of China (11505101). *E-mail:pengjun@ihep.ac.cn
	Slides TUOBA1 [4.272 MB]
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TUOBB1	Experimental Demonstration of Energy-Chirp Reduction by a Plasma Dechirper	plasma, electron, laser, experiment	1258
	Y.P. Wu, Z. Cheng, Y.-C. Du, J.F. Hua, W. Lu, C.H. Pai, J. Zhang, S.Y. Zhou, Z. Zhou TUB, Beijing, People's Republic of China
	The first experimental study is presented using a low density plasma dechirper to reduce a correlated energy chirp from the 41.5-MeV, 500-fs (RMS) beam at the linac in Tsinghua University. The plasma dechirper operates through the interaction of the electron bunch with its near linear self-wake to dechirp itself, leading to a reduction in energy spread. The experimental results demonstrate that the projected FWHM energy spread of the beam can be reduced from 1.2% to 0.9% with a 12 mm long plasma dechirper, which are in good agreement with full 3D PIC simulations. Theoretical analyses and simulations indicate that by optimizing the plasma density and length, the plasma dechirper can also be used to completely remove the characteristic energy chirp of the ultra-short high-current bunch generated from plasma based accelerator, such that its energy spread can be reduced from one percent level to 0.1 percent level[]. Application of such a simple and effective method can significantly improve the beam quality and provide the path to realize the future compact free electron lasers and colliders driven by plasma based accelerators. [] Y. P. Wu. A plasma dechirper for electron and positron beams in plasma-based accelerators, to be submitted to Scientific Reports
	Slides TUOBB1 [10.555 MB]
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TUZB1	Final Results From the Clic Test Facility (CTF3)	operation, acceleration, emittance, beam-loading	1269
	R. Corsini CERN, Geneva, Switzerland
	The unique CLIC TEST Facility (CTF3) has been built more than a decade ago to demonstrate the feasibility of the CLIC two beam acceleration scheme. The emphasis was one the high current drive beam generation using a fully loaded highly efficient linac and a complex combination scheme to increase beam current and bunch repetition frequency. This drive beam has been used for deceleration experiments and two beam acceleration. A wealth of relevant results for accelerator physics even beyond CLIC has been obtained and will be presented. The rf to beam efficiency of the linac exceeds 95%, after combination the 28 A drive beam with 12 GHz bunch repetition rate has been used to extract more than 50% of its energy producing 1.3 GW of 12 GHz power as well as performing two beam acceleration at 12 GHz with gradients up to 150 MV/m.
	Slides TUZB1 [23.702 MB]
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TUOCB3	CBETA - Cornell University Brookhaven National Laboratory Electron Energy Recovery Test Accelerator	electron, permanent-magnet, acceleration, gun	1285
	D. Trbojevic, S. Bellavia, J.S. Berg, M. Blaskiewicz, S.J. Brooks, K.A. Brown, W. Fischer, F.X. Karl, C. Liu, G.J. Mahler, F. Méot, R.J. Michnoff, M.G. Minty, S. Peggs, V. Ptitsyn, T. Roser, P. Thieberger, N. Tsoupas, J.E. Tuozzolo, F.J. Willeke, H. Witte BNL, Upton, Long Island, New York, USA N. Banerjee, J. Barley, A.C. Bartnik, I.V. Bazarov, D.C. Burke, J.A. Crittenden, L. Cultrera, J. Dobbins, B.M. Dunham, R.G. Eichhorn, S.J. Full, F. Furuta, R.E. Gallagher, M. Ge, B.K. Heltsley, G.H. Hoffstaetter, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, W. Lou, C.E. Mayes, J.R. Patterson, P. Quigley, D.M. Sabol, D. Sagan, J. Sears, C.H. Shore, E.N. Smith, K.W. Smolenski, V. Veshcherevich, D. Widger Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA D. Douglas JLab, Newport News, Virginia, USA D. Jusic, J.R. Patterson Cornell University, Ithaca, New York, USA
	Funding: New York State Energy Research and Development Authority (NYSERDA) Cornell's Lab of Accelerator-based Sciences and Education (CLASSE) and the Collider Accelerator Department (BNL-CAD) are developing the first SRF multi-turn energy recovery linac with Non-Scaling Fixed Field Alternating Gradient (NS-FFAG) racetrack. The existing injector and superconducting linac at Cornell University are installed together with a single NS-FFAG arcs and straight section at the opposite side of the the linac to form an Electron Energy Recovery (ERL) system. Electron beam from the 6 MeV injector is injected into the 36 MeV superconducting linac, and accelerated by four successive passes: from 42 MeV up to 150 MeV using the same NS-FFAG structure made of permanent magnets. After the maximum energy of 150 MeV is reached, the electron beam is brought back to the linac with opposite Radio Frequency (RF) phase. Energy is recovered and reduced to the initial value of 6 MeV with 4 additional passes. There are many novelties: a single NS-FFAG structure, made of permanent magnets, brings electrons with four different energies back to the linac. A new adiabatic NS-FFAG arc-to-straight section merges 4 separated orbits into a single orbit in the straight section.
	Slides TUOCB3 [41.888 MB]
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TUPAB004	Progress of 7-GeV SuperKEKB Injector Linac Upgrade and Commissioning	positron, gun, injection, electron	1300
	K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, H. Ego, A. Enomoto, Y. Enomoto, S. Fukuda, Y. Funahashi, T. Higo, H. Honma, N. Iida, M. Ikeda, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, M. Kawamura, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, H. Nakajima, K. Nakao, T. Natsui, M. Nishida, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, I. Satake, D. Satoh, M. Satoh, Y. Seimiya, A. Shirakawa, H. Sugimoto, H. Sugimura, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, N. Toge, Y. Yano, K. Yokoyama, M. Yoshida, R. Zhang, X. Zhou KEK, Ibaraki, Japan
	KEK injector linac has delivered electrons and positrons for particle physics and photon science experiments for more than 30 years. It is being upgraded for the SuperKEKB project, which aims at a 40-fold increase in luminosity over the previous project KEKB, in order to increase our understanding of new physics beyond the standard model of elementary particle physics. SuperKEKB asymmetric electron and positron collider with its extremely high luminosity requires a high current, low emittance and low energy spread injection beam from the injector. Electron beams will be generated by a new type of RF gun, that will provide a much higher beam current to correspond to a large stored beam current and a short lifetime in the ring. The positron source is another major challenge that enhances the positron bunch intensity from 1 to 4 nC by increasing the positron capture efficiency, and the positron beam emittance is reduced from 2000 micron to 20 micron in the vertical plane by introducing a damping ring, followed by the bunch compressor and energy compressor. The recent status of the upgrade and beam commissioning is reported.
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TUPAB005	Investigation of Beam Variation and Emittance Growth Simulation With Both Misalignments and the Beam Jitter for SuperKEKB Injector Linac	emittance, electron, simulation, quadrupole	1304
	Y. Seimiya, K. Furukawa, T. Higo, F. Miyahara, M. Satoh, T. Suwada KEK, Ibaraki, Japan
	Funding: This work was supported by JSPS KAKENHI Grant Number 16K17545. The SuperKEKB is e⁺/e⁻ circular collider for high luminosity, 8Â¥times10³⁵ as a target value. For the high luminosity, the injector linac is required to transport low emittance high-charged electron beam and positron beam to the ring. A charged beam with an offset from a center of cavity is affected by the wakefield depending on both the offset size in the cavity and longitudinal particle position in the beam. The wakefield causes emittance growth. This growth can be suppressed by appropriate orbit control so as to cancel the wakefield effect of the cavities in total. On the other hands, the beam variation in 6-dimensional phase space also induces the emittance growth. Emittance growth by both misalignments and 6-dimensional beam jitter was evaluated by particle tracking simulation. Investigation of beam jitter and drift was also performed by correlation analysis between beam position and measured parameter, charge or temperature.
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TUPAB008	CEPC Linac Design and Beam Dynamics	positron, electron, target, quadrupole	1315
	C. Meng, Y.L. Chi, X.P. Li, G. Pei, S. Pei, D. Wang, J.R. Zhang IHEP, Beijing, People's Republic of China
	Circular Electron-Positron Collider (CEPC) is a 100 km ring e⁺ e⁻ collider for a Higgs factory, which is organized and led by the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences (CAS) in collaboration with a number of institutions from various countries. The linac of CEPC is a normal con-ducting S-band linac with frequency in 2856.75 MHz and provide electron and positron beam at an energy up to 10 GeV with bunch charge in 1.0 nC and repetition frequency in 100 Hz. The linac scheme will be detailed discussed in this paper, including electron bunching system, positron source design, and main linac. Positrons are generated using a 4 GeV electron beam with bunch charge 10 nC hit tungsten target and the positron source design are presented. The beam dynamic results with longitudinal short Wakefield, transverse Wakefield and errors are presented.
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TUPAB009	Design Study on CEPC Positron Damping Ring and Bunch Compressor	damping, positron, emittance, injection	1318
	D. Wang, Y.L. Chi, J. Gao, X.P. Li, C. Meng, J.R. Zhang IHEP, Beijing, People's Republic of China G. Pei Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	The primary purpose of CEPC damping ring is to reduce the transverse phase spaces of positron beam to suitably small value at the beginning of Linac and also adjust the time structure of positron beam for reinjection into the Linac. Longitudinal bunch length control was provided to minimize wake field effects in the Linac by a bunch compressor system after the damping ring. Both designs for damping ring and bunch compressor were discussed in this paper.
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TUPAB010	High-Gradient Breakdown Studies of X-Band Choke-Mode Structures	cavity, operation, collider, linear-collider	1322
	X.W. Wu, H.B. Chen, J. Shi, H. Zha TUB, Beijing, People's Republic of China T. Abe, T. Higo, S. Matsumoto KEK, Ibaraki, Japan
	As an alternative design for Compact Linear Collider (CLIC) main accelerating structures, X-band choke-mode damped structures had been studied for several years. However, the performance of choke-mode cavity under high power is still in lack of research. Two standing-wave single-cell choke-mode damped accelerating structures working at 11.424 GHz and one reference structure without choke were designed, manufactured, low-power measured, and tuned by accelerator group at Tsinghua University. High-power test had been done on them to study the breakdown phenomenon in high gradient and how the choke affects high-gradient properties. A max gradient of 75 MV/m were achieved by the choke-mode structure and the choke breakdown limited further increasing of the gradient. Inner surface inspection of the choke-mode structures indicates that the axial part of the choke limits the performance of the structure. Based on this observation, three new choke-mode structures were designed and being manufactured.
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TUPAB011	Beam Dynamics Simulation in Two Versions of New Photogun for FCC-ee Electron Injector Linac	injection, simulation, electron, beam-loading	1326
	S.M. Polozov, T.V. Bondarenko MEPhI, Moscow, Russia
	New high-energy frontier project FCC is now under development at CERN. The project includes three modes: ee, hh and eh interactions for FCC. New injection system for FCC-ee is planned to consist of new ~ 2-14 GeV electron linac and electron-positron converter. Injector linac should provide two regimes: ~250 pC bunches for injection and ~6 nC bunches for e⁻/e⁺ conversion. Two possible schemes of photogun are comprised and results of beam dynamics simulation in both FCC-ee injection linac photoguns are discussed.
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TUPAB012	Comparison of Prismatic and Circular Biperiodical Accelerating Structures of 27 GHz Operating Frequency	coupling, simulation, impedance, alignment	1330
	Yu.D. Kliuchevskaia, S.M. Polozov MEPhI, Moscow, Russia
	As known a biperiodical accelerating structure (BAS) represents as a system based on disk loaded waveguide (DLW) operating on Pi/2 mode and is widely used for the compact electron linacs. Earlier such structure with operating frequency of 27 GHz was proposed for medical application and beam dynamics simulations and electrodynamics modeling were done [1-2]. It was shown that such structure manufacturing should have very high accuracy and can be manufactured using electro erosive technology only. It is very complex for axi-symmetrical geometry to use such technology. Interesting option will to use a prismatic geometry BAS. In this report the design of a prismatic and disk-loaded BAS will discus, simulation results and analysis will presented.
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TUPAB013	Beam Dynamics Study and Electrodynamics Simulations for the CW RFQ	rfq, cavity, simulation, Windows	1333
	S.M. Polozov, W.A. Barth, T. Kulevoy, Y. Lozeev, S. Yaramyshev MEPhI, Moscow, Russia W.A. Barth, S. Yaramyshev GSI, Darmstadt, Germany W.A. Barth HIM, Mainz, Germany T. Kulevoy, S.M. Polozov ITEP, Moscow, Russia
	A compact university scale CW research proton accelerator, as well as driver linac with three branches of experimental beam lines, delivering beam energy of 3, 30 and 100 MeV for experiments, are recently under development in Russia. First results of the beam dynamics simulations for such a linac were already shown in . The recently developed advanced RFQ cavity design is presented. The low energy beam transport line (LEBT), dedicated to transport proton beam from an ECR ion source, as well as to match beam emittance to the RFQ acceptance, was investigated. The results of beam dynamics simulations for LEBT are discussed. W.Barth, T.Kulevoy, S.Polozov, S.Yaramyshev, Proc. of HB-2016, 188-190.
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TUPAB014	Preliminary Design of FCC-ee Pre-Injector Complex	emittance, damping, positron, booster	1337
	S. Ogur, Y. Papaphilippou, F. Zimmermann CERN, Geneva, Switzerland A.M. Barnyakov, A.E. Levichev, D.A. Nikiforov BINP SB RAS, Novosibirsk, Russia K. Furukawa, N. Iida, F. Miyahara, K. Oide KEK, Ibaraki, Japan
	The design of a 100 km circular e⁺e⁻ collider with extremely high luminosity is an important component of the global Future Circular Collider (FCC) study hosted by CERN. FCC-ee is being designed to serve as Z, W, H and top factory, covering beam energies from 45.6 to 175 GeV. For the injectors, the Z-operation is the most challenging mode, due to the high total charge and low equilibrium emittance in the collider at this energy. Thus, fulfilling the Z-mode will also meet the demands for all other modes of FCC-ee. This goal can be achieved by using a 6 GeV NC linac with an S-band RF frequency of 2.856 GHz and a repetition rate of 100 Hz. This linac will accelerate two bunches per RF pulse, each with a charge of 6.5 nC. Positrons will be generated by sending 4.46 GeV e^- onto a hybrid target so that the e⁺ created can still be accelerated to 1.54 GeV in the remaining part of the same linac. The emittance of the e⁺ beam will then shrink to the nm level in a 1.54 GeV damping ring. After damping, the e⁺ will be reinjected into the linac and accelerated to 6 GeV. The e^- and e⁺ will then be accelerated alternately to 45.6 GeV in the booster, before they are injected into the collider.
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TUPAB016	The CLIC Main Linac Module Updated Design	alignment, klystron, operation, luminosity	1345
	C. Rossi, M. Aicheler, N. Catalán Lasheras, R. Corsini, S. Döbert, A. Grudiev, A. Latina, H. Mainaud Durand, M. Modena, H. Schmickler, D. Schulte, S. Stapnes, I. Syratchev, A.L. Vamvakas, W. Wuensch CERN, Geneva, Switzerland M. Aicheler HIP, University of Helsinki, Finland
	In 2016, CLIC implementation working groups have started their reflection on how to finalize the CLIC design work in the different areas of the project, aiming for a technical design and an overall implementation plan for CLIC being available for the next European Strategy Update around 2019. One of the working groups has focused its attention on the Main Linac hardware, which has brought together the different competences of the study with the aim of producing an advanced set of specifications for the design, installation and operation of the CLIC module. As the fundamental unit for the construction of the Main Beam linac, the CLIC module needs to move from the existing prototypes exploring its performance into an advanced and functional unit where the full life cycle of the module is considered. The progress of the working group activity is summarized in this paper, with considerations on the requirements for the design of the next-phase CLIC module.
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TUPAB017	Results of the Beam-Loading Breakdown Rate Experiment at the CLIC Test Facility CTF3	beam-loading, experiment, operation, klystron	1348
	E. Senes, T. Argyropoulos, N. Catalán Lasheras, R. Corsini, D. Gamba, J. Giner Navarro, A. Grudiev, G. McMonagle, R. Rajamaki, X.F.D. Stragier, I. Syratchev, F. Tecker, W. Wuensch CERN, Geneva, Switzerland J. Giner Navarro IFIC, Valencia, Spain R. Rajamaki Aalto University, School of Science and Technology, Aalto, Finland E. Senes Torino University, Torino, Italy
	The RF breakdown rate is crucial for the luminosity performance of the CLIC linear collider. The required breakdown rate at the design gradient of 100 MV/m has been demonstrated, without beam presence, in a number of 12 GHz CLIC prototype structures. Nevertheless, the beam-loading at CLIC significantly changes the field profile inside the structures, and the behaviour with beam needs to be understood. A dedicated experiment in the CLIC Test Facility CTF3 to determine the effect of beam on the breakdown rate has been collecting breakdown data throughout the year 2016. The complete results of the experiment and the effect of the beam-loading on the breakdown rate are presented.
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TUPAB022	TRIUMF ARIEL e-Linac Ready for 30 MeV	cavity, cryomodule, TRIUMF, electron	1361
	S.R. Koscielniak, Z.T. Ang, K. Fong, J.J. Keir, O.K. Kester, M.P. Laverty, R.E. Laxdal, Y. Ma, A.K. Mitra, T. Planche, D.W. Storey, E. Thoeng, B.S. Waraich, Z.Y. Yao, V. Zvyagintsev TRIUMF, Vancouver, Canada
	Funding: TRIUMF is funded under a contribution agreement with the National Research Council of Canada. The ARIEL electron linac (e-linac) in its present configuration has a 10 mA electron gun and a single-cavity 10 MeV injector cryomodule followed by the accelerator cryomodule intended to house two 10-MeV-capable SRF cavities. There are momentum analysis stations at 10 MeV and 30 MeV. In October 2014, using a total of two cavities, the e-linac demonstrated 22.9 MeV acceleration. In 2017 an additional SRF cavity was installed in the accelerator cryomodule, thereby completing its design specification; and leading to 30 MeV acceleration capability. The 9-cell 1.3 GHz cavities are a variant of the TESLA type, modified for c.w. operation and recirculation. An unusual feature of the module is the power feed of two cavities by one klystron through a wave-guide type power divider, and closed loop control of the combined voltage from the cavities. Initial operation of the two-cavity control, including power and phase balancing, is reported.
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Paper

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MOXAA1

Commissioning of the European XFEL Accelerator

operation, electron, undulator, emittance

1

W. Decking, H. Weise
DESY, Hamburg, Germany

The European XFEL uses the world's largest superconducting RF installation to drive three independent SASE FELs. After eight years of construction the facility is now brought into operation. First experience with the superconducting accelerator as well as beam commissioning results will be presented. The path to the first user experiments will be laid down.

Slides MOXAA1 [22.967 MB]

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MOXBA1

Progress on the ESS Project Construction

target, controls, cryomodule, klystron

7

R. Garoby
ESS, Lund, Sweden

The construction of the European Spallation Source (ESS) is advancing at a high pace with the support of many laboratories and institutions all over Europe. Prototyping and manufacturing for the accelerator are in full swing in more than 23 laboratories distributed over 12 European partner countries. The origin and goals of the ESS will be briefly outlined in this paper. The milestones achieved, both in Lund and at the partner labs will be described as well as the plans up to operations.

Slides MOXBA1 [76.192 MB]

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MOYCA1

Ultimate Field Gradient in Metallic Structures

klystron, collider, damping, linear-collider

24

W. Wuensch
CERN, Geneva, Switzerland

Significant progress has been made over the past decade by studies of normal-conducting linear colliders, NLC/JLC (Next/Japanese Linear Collider) and CLIC (Compact Linear Collider), to raise achievable accelerating gradient from the range of 20-30 MV/m up to 100-120 MV/m. The gain has come through a greatly increased understanding of high-power rf phenomena, development of quantitative high-gradient rf design methods, refinements in cavity fabrication techniques and through development of high peak rf power sources. Recently accelerating gradients in excess of 100 MV/m, at very low breakdown rates, have been successfully achieved with new techniques of conditioning in numerous prototypes at different laboratories. The talk will report on the impact of these new results on the understanding of the physics of breakdown and of conditioning, and on the ultimate gradients that can be expected in metallic RF structures.

Slides MOYCA1 [52.087 MB]

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MOPAB016

Beam Diagnostic and Control Systems for AREAL 50 MeV Linac

controls, electron, emittance, diagnostics

114

V. Sahakyan, G.A. Amatuni, A. Azatyan, B. Grigoryan, N. Martirosyan, A. Sargsyan, V.M. Tsakanov, G.S. Zanyan
CANDLE SRI, Yerevan, Armenia

Advanced Research Electron Accelerator Laboratory (AREAL) is an electron linear accelerator project with a laser driven RF gun that has been constructed at CANDLE Synchrotron Research Institute. After the completion of the first phase, which implies the operation of a 5 MeV gun section, the second phase of facility development (energy enhancement up to 50 MeV) is in progress. In the present paper the description of corresponding upgrades for diagnostic and control systems is given.

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MOPAB021

Performance of OTR and Scintillator View Screens for the ARIEL Electron Linac

target, optics, radiation, scattering

117

D.W. Storey, J.M. Abernathy, D. Karlen, M.O. Pfleger, P.R. Poffenberger
Victoria University, Victoria, B.C., Canada
P.S. Birney, P.E. Dirksen, S.R. Koscielniak, M. Lenckowski
TRIUMF, Vancouver, Canada

The ARIEL electron linac is a 0.3 MW CW accelerator, extensible to 0.5 MW, being installed at TRIUMF for radioactive beam production. To date, 17 view screen monitors have been installed along the beamline and have proven to be essential tools in the commissioning of e-linac systems. These are populated by two types of beam targets: P46 scintillator screens which provide diagnostics for low duty factor operation, while at locations with beam energies at and above 10 MeV, OTR foils using either Pyrolytic Graphite or Niobium foils are included to provide coverage up to 100's of μA average beam current. The design of the view screen is described including the image acquisition system and beam target selection. The performance thus far of the OTR foils under low duty factor commissioning is presented including quantification of the OTR emission distribution, thermal studies, and transmission of the beam through the linac after intercepting a foil.

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MOPAB022

Fabrication Studies of a 650 MHz Superconducting RF Deflecting Mode Cavity for the ARIEL Electron Linac

cavity, niobium, electron, impedance

120

D.W. Storey, R.E. Laxdal, B. Matheson, N. Muller
TRIUMF, Vancouver, Canada
D.W. Storey
Victoria University, Victoria, B.C., Canada

A 650 MHz RF deflecting mode cavity is required for the ARIEL electron Linac to separate interleaved beams bound for either rare isotope production or a recirculation loop containing a Free Electron Laser. An RF separator will allow both modes to run simultaneously by imparting opposite transverse deflection to adjacent bunches at 1.3 GHz. The SRF cavity has been designed to provide up to 0.6 MV transverse voltage for operation with up to a 50 MeV CW electron beam. The design was optimised for compact geometry with high shunt impedance. Due to the low dissipated power, the cavity will operate at 4 K and allows for investigations into low cost fabrication techniques. The cavity is being machined from bulk reactor grade ingot Niobium and welds will be performed using TIG welding in an ultra-pure Argon chamber. Results of fabrication studies will be presented as well as measurements performed on a copper prototype cavity.

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MOPAB024

Proposal to Observe Half-Bare Electrons on a 40-MeV LINAC

electron, radiation, experiment, laser

126

N. Delerue, S. Jenzer, V. Khodnevych, A. Migayron
LAL, Orsay, France
N.F. Shul'ga
NSC/KIPT, Kharkov, Ukraine
S. Trofymenko
KhNU, Kharkov, Ukraine

Funding: CNRS/IN2P3 and Joint Laboratory France-Ukraine IDEATE
In different processes of relativistic electron interaction with substance and external fields, the electron loses part of its Coulomb field and becomes half-bare. Such state of electron significantly modifies the characteristics of its electromagnetic radiation during further interaction of the particle with substance. We propose to study the influence of the half-bare state of electron upon its transition radiation (TR). The existence of such influence for the case of electron undressing at its scattering was theoretically predicted. We intend to obtain the electrons in half-bare state in the result of their crossing of a conducting screen such as a TR screen. We propose to investigate the influence of the half-bare state of electron in this process upon TR generated by such electron on a downstream TR screen situated on some distance from the upstream screen which undresses the particle. Calculations are presented for the case of a 45-MeV linac and the distance between the screens in the region between 100 mm and 300 mm. The proposed experiment is expected to reveal new features of TR signal in such process comparing to previous measurements.
N.F. Shul'ga, S.V. Trofymenko, V.V. Syshchenko, JETP Lett. 93 (2011) 1.
Y. Shibata, K. Ishi, T. Tokahashi et al., Phys. Rev. E 49 (1994) 785.

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MOPAB025

Measurement of the Polarisation of Coherent Smith-Purcell Radiation in the SOLEIL Linac

radiation, polarization, detector, experiment

129

N. Delerue, S. Jenzer, V. Khodnevych
LAL, Orsay, France
N. Hubert, M. Labat, J.-P. Pollina, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

Funding: CNRS/IN2P3, Université Paris-Sud and ANR (contract ANR-12-JS05-0003-01)
SPESO is an experiment installed in the Linac of Synchrotron SOLEIL to study the Coherent Smith-Purcell radiation produced when a grating is approached from the beam. The detectors used to measure this radiation are mounted on 3-translation axis and 2 rotation axis. This allows measurements of the radiation emission map around the grating. In addition a polarizer has been added in 2016 allowing to study the two polarization components of the radiation in this map. Preliminary results of this mapping will be presented.

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MOPAB033

Optics Development and Trajectory Tuning of BERLinPro at Low Energies

gun, booster, diagnostics, SRF

153

B.C. Kuske, M. Abo-Bakr
HZB, Berlin, Germany

Funding: Work supported by the German Bundesministerium fr Bildung und Forschung, Land Berlin and grants of the Helmholtz Association
The Berlin Energy Recovery Linac project has taken shape during the past year. The magnets have been set up in the newly constructed subterraneous hall; first electrons are expected in the SRF-gun test laboratory in June 2017. Starting in February 2018 the complete gun module will be transferred to the accelerator hall for the commissioning of BERLinPro. For the first months, operation is planned without further accelerating structures (booster and linac), due to delays in their fabrication. Several modes of operation are applicable at this early stage [1]. The available hardware is displayed and the adapted optics at 2.7 MeV and at 6.5 MeV (including the booster) are presented. The trajectory distortions under the influence of the earth magnetic field are studied. The concept for trajectory correction is outlined.

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MOPAB048

Simulation of fs Bunch Length Determination with the 3-Phase Method and THz Dielectric Loaded Waveguides

injection, space-charge, simulation, electron

199

T. Vinatier, R.W. Aßmann, U. Dorda, B. Marchetti
DESY, Hamburg, Germany

In this paper, we investigate with ASTRA simulations the capability of the 3-phase method to reconstruct the length of a fs electron bunch. We show that a standard 3 GHz travelling wave accelerating structure is not suited for this purpose, because of the too important effect of the space-charge forces and of the too small variations of the induced energy spread with the bunch injection phase. Our simulations demonstrate that the use of dielectric-loaded waveguides driven by THz pulses would allow overcoming these two limitations and possibly achieving an ultimate resolution better than 5% for the determination of a 6.25 fs rms bunch length at 100 MeV energy and 1 pC charge. The next steps of the study to better evaluate, in simulations and experiments, the possible sources of degradation of the 3-phase method resolution are also mentioned.

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MOPAB049

Development of a Focusing System for the AXSIS Project

solenoid, quadrupole, plasma, focusing

203

T. Vinatier, R.W. Aßmann, U. Dorda, B. Marchetti
DESY, Hamburg, Germany

In this paper, we investigate with ASTRA simulations the achievable performances for several focusing systems considered in the AXSIS project. We focus our attention on the requirements in terms of position of the focal point and bunch transverse size at this point. We show that they cannot be fulfilled with a solenoid resistive electro-magnet, but that it is possible when using a solenoid permanent magnet. The use of a quadrupole doublet proves to be adequate to fulfil the requirement on the position of the focal point and be very close to the one on the bunch transverse size, which could possibly be achieved by a further optimization of the parameters of the doublet. Finally, we also investigate the possibility to use an active plasma lens, showing that it could easily fulfil the requirements but that several points must be carefully studied before considering its implementation.

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MOPAB057

Analysis and Correction of Geometrical Non-Linearities of ELI-NP BPMs on Position and Current Measurements

electron, laser, photon, instrumentation

235

G. Franzini, F. Cioeta, O. Coiro, V.L. Lollo, D. Pellegrini, S. Pioli, A. Stella, A. Variola
INFN/LNF, Frascati (Roma), Italy
M. Marongiu
INFN-Roma, Roma, Italy
A. Mostacci
University of Rome La Sapienza, Rome, Italy
A.A. Nosych
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
L. Sabato
U. Sannio, Benevento, Italy

The advanced source of Gamma-ray photons will be soon built near Bucharest (Romania) by an European consortium (EurogammaS) led by INFN, as part of the ELI-NP (Extreme Light Infrastructure-Nuclear Physics). It will generate photons by Compton back-scattering in the collision between a multi-bunch electron beam, at a maximum energy of 720 MeV, and a high intensity recirculated laser pulse. An S-Band photo-injector and the following C-band Linac, which are under construction, will operate at 100Hz repetition rate with macro pulses of 32 electron bunches, separated by 16ns and with 250pC nominal charge. Stripline and cavity BPMs will be installed along the linac, in order to measure both the position and charge of the electron beam. Stripline BPM response can be considered linear within a limited area around the BPM origin. In order to use the full BPM acceptance area, without accuracy losses due to non-linearities, we plan to use correction algorithms, developed on the basis of simulations and measurements of BPMs response. In particular, suitable high-order surface polynomials will be used.

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MOPAB058

Optical Issues for the Diagnostic Stations for the ELI-NP Compton Gamma Source

target, diagnostics, electron, laser

238

M. Marongiu, D. Cortis
INFN-Roma, Roma, Italy
E. Chiadroni, F. Cioeta, G. Di Pirro, G. Franzini, V. Shpakov, A. Stella, A. Variola
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
A. Mostacci, L. Palumbo
University of Rome La Sapienza, Rome, Italy
L. Sabato
U. Sannio, Benevento, Italy

A high brightness electron Linac is being built in the Compton Gamma Source at the ELI Nuclear Physics facility in Romania. To achieve the design luminosity, a train of 32 bunches, 16 ns spaced, with a nominal charge of 250 pC will collide with the laser beam in the interaction point. Electron beam spot size is measured with optical transition radiation (OTR) profile monitors. In order to measure the beam properties, the optical radiation detecting system must have the necessary accuracy and resolution. This paper deals with the studies of different optic configurations to achieve the magnification, resolution and accuracy in order to measure very small beam (below 30 um) or to study the angular distribution of the OTR and therefore the energy of the beam. Several configurations of the optical detection line will be studied both with simulation tools (e.g. Zemax) and experimentally. The paper will deal also with the sensibility of optic system (in terms of depth of field, magnification and resolution) to systematic errors.

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MOPAB059

Energy Chirp Measurements by Means of an RF Deflector: a Case Study the Gamma Beam Source LINAC at ELI-NP

electron, brightness, detector, simulation

242

L. Sabato
U. Sannio, Benevento, Italy
P. Arpaia, A. Liccardo
Naples University Federico II, Science and Technology Pole, Napoli, Italy
A. Mostacci, L. Palumbo
University of Rome La Sapienza, Rome, Italy
A. Variola
INFN/LNF, Frascati (Roma), Italy

RF Deflector (RFD) based measurements are widely used in high–brightness electron LINAC around the world in order to measure the ultra–short electron bunch length. The RFD provides a vertical kick to the particles of the electron bunch according to their longitudinal positions. In this paper, a measurement technique for the bunch length and other bunch proprieties, based on the usage of an RFD, is proposed. The basic idea is to obtain information about the bunch length, energy chirp, and energy spread from vertical spot size measurements varying the RFD phase, because they add contributions on this quantity. The case study is the Gamma Beam System (GBS), the Compton Source being built in the Extreme Light Infrastructure–Nuclear Physics (ELI–NP) facility. The ELEctron Generation ANd Tracking (ELEGANT) code is used for tracking the particles from RFD to the measurement screen.

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MOPAB061

DAΦNE BTF Improvements of the Transverse Beam Diagnostics

software, detector, timing, positron

250

P. Valente
INFN-Roma, Roma, Italy
B. Buonomo, D.G.C. Di Giulio, L.G. Foggetta
INFN/LNF, Frascati (Roma), Italy

The DAΦNE BTF (beam-test facility) can provide electrons and positrons, tuning at runtime different beam parameters: energy (from about 50 MeV up to 750 MeV for e^- and 540 MeV for e+), intensity (from single particle up to 10¹⁰/bunch) and pulse length (in the range 1.5-40 ns) up to 49 Hz, depending on the operations of the DAΦNE collider. The beam spot and divergence can be adjusted, down to sub-mm sizes and 2 mrad (downstream of the vacuum beam-pipe exit window), matching the user needs. We describe of the BTF beam transverse monitor systems based on FitPIX detectors, operating in bus synchronization mode externally timed to the BTF beam. We also describe our custom software allowing the acquisition and synchronization of the beam diagnostics with the users data, using TCP/IP calls to MEMCACHED. The performance of the system in a variety of beam intensity, energy and focusing conditions is reported.

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MOPAB067

Response of Scintillating Screens to High Charge Density Electron Beam

electron, quadrupole, diagnostics, experiment

268

F. Miyahara, S. Kishimoto, M. Satoh, Y. Seimiya, T. Suwada
KEK, Ibaraki, Japan
M. Koshimizu
Tohoku University, School of Science, Sendai, Japan

Inorganic scintillating screens are very useful tool to measure transverse profile of charged particle beams. The cerium-doped yttrium:aluminum:garnet (YAG:Ce) crystal scintillator is used in many accelerating facilities. The scintillating screen shows good resolution comparable to that of OTR screen. However, response to high charge density electron beam, more than 10 nC per square millimeter, has not been clarified. In KEK e⁺/e⁻ injector linac, the charge areal density (σ) will exceed 25 nC per square mm. Thus, beam tests has been performed on YAG:Ce, LYSO, and BGO crystals for 1.5 GeV, 1 nC/bunch electron beam at the linac. Saturation of the luminescence which causes degradation of the resolution has been observed above 1 nC per square mm in those crystals. We will report the response of the scintillating screens to high charge density electron beam and discuss the degradation of the resolution due to the saturation of the light yield.

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MOPAB070

Beam Position Measurement During Multi-Turn Painting Injection at the J-PARC RCS

injection, operation, proton, synchrotron

277

N. Hayashi, A. Miura, P.K. Saha, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

Multi-turn painting injection scheme is important for high intensity proton accelerators. At the J-PARC RCS, a transverse painting scheme was adapted by adding vertical painting magnets to the beam transport line before the injection point, with horizontal painting being performed by a set of dedicated pulse magnets in the ring. To establish a transverse painting condition, it is usual to base on the pulse magnet current pattern. However, it is more desirable to directly measure the beam orbit time variation for evaluation. A linac beam was chopped to match the ring RF bucket. We thought that it would be difficult to measure the position for each pulse; however, the average position could be extracted by introducing a particular device. For the beam injected into the ring, because the linac RF frequency component was diminished due to debunching quickly, one could determine its position in the beginning of the injection period. However, due to rebunching effect the position determination becomes difficult. This problem needs to be resolved.

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MOPAB071

A Beam Position Monitor for the Diagnostic Line in MEBT2 of J-PARC Linac

diagnostics, pick-up, impedance, operation

281

A. Miura, Y. Kawane, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan
T. Miyao
KEK, Ibaraki, Japan

In the linac of the Japan Proton Accelerator Research Complex (J-PARC), the neutral hydrogen (H⁰) generation from the negative hydrogen ion (H⁻) beam is one of key issues to mitigate the beam loss. In order to diagnose the H⁰ particles, we installed the bump magnets to make a chicane orbit of the H⁻ beam. To evaluate the horizontal shifts of the beam orbit, a beam position monitor (BPM) is fabricated. The BPM measures the shift-positions with various driving currents of the bump magnets. We employed the WSM to measure the H⁻ beam profile. It also help us to compare the shift-positions measured by BPM. In this paper, the design and the performance of the BPM is described. In addition, we describe how to compare the shift position.

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MOPAB074

Low Intensity Electron Beam Controlling and Monitoring

electron, detector, controls, experiment

292

L. Yu, Y. Li, Y.F. Sui, J.H. Yue
IHEP, Beijing, People's Republic of China

To calibrating a cosmic-ray detector, a low beam current accelerator has been built to generate ultra low intensity electron beams at Institute of High Energy Physics (IHEP). The minimum beam charge obtained was estimated to be about one electron/pulse. Beam commissioning has been carried out. The key technologies for achieving such low intensity electron beams are to control the beam using 8 movable slits and to measure the intensity of the beam using 9 movable current monitors based on scintillator. In this paper, principal of operation, instrumentation and programming of the movable slits and movable current monitors are discussed. Some results of beam commissioning are also presented.

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MOPAB088

A Differential Beam Intensity Monitoring for the CIADS LINAC

monitoring, simulation, instrumentation, pick-up

325

Z.P. Xie
Hohai University, Nanjing, People's Republic of China
Y. He, R. Huang, Z.J. Wang
IMP/CAS, Lanzhou, People's Republic of China

Funding: Work supported by the National Natural Science Foundation of China (Grant No. 91026001) and the Fundamental Research Funds for the Chinese Central Universities
The high power Linac places many crucial requirements on the beam diagnostics for the China initiative accelerator driven subcritical(CIADS) facility. Measuring the beam loss is essential for the purpose of machine protections for the facility. A beam position pickup based differential beam current monitoring (BPDBCM) scheme has been proposed for the MEBT section at CIADS. Discussions of the principles for the scheme and the realtionship between beam intensity measurement and the pulse length are presented. Simulations are performed and they demonstrate that the proposed system can be effective at the low enery section for the CIADS beam. This paper describes the proposed implementation that will have the capability of detecting both the instantaneous and chronicle loss in real time.

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MOPAB098

Coronagraph Based Beam Halo Monitor Development for BERLinPro

background, electron, dipole, scattering

355

J.G. Hwang
Kyungpook National University, Daegu, Republic of Korea
J. Kuszynski
HZB, Berlin, Germany

For linac based high power electron machines, beam halo induced by nonlinear space charge force and scattering of trapped ions is one of the critical issues on a machine protection system. It causes additional radiation which can be a heat source on a cryogenic system as a result of uncontrolled beam losses. During the last decades, several instruments have been newly developed for measuring the beam halo distribution. The conceptual design and optimization of the coronagraph based halo monitor were performed to measure the beam halo which has ~ 10^-3 contrast to the beam core.

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MOPAB099

Design Study of Drift Tube Linac for BNCT Accelerator

DTL, quadrupole, simulation, rfq

359

Y. Lee, S.W. Jang, E.-S. Kim
Korea University Sejong Campus, Sejong, Republic of Korea
B.H. Choi
IBS, Daejeon, Republic of Korea
D.S. Kim
Dawonsys, Siheung-City, Republic of Korea
Z. Li
SCU, Chengdu, People's Republic of China

A-BNCT accelerator is being developed as a proton accelerator with a high beam current of 50 mA for effective cancer therapy. Drift tube linac (DTL) with the length of 4.5 m is composed of 1 tank and 48 drift tubes (DTs). Proton beam is accelerated from 3 MeV to 10 MeV. Electromagnetic quadrupoles (EMQs) are inserted into every DT for transverse focusing. Slug tuners and post couplers (PCs) are used for accelerating field stabilization and resonant frequency tuning, respectively. The beam dynamics and engineering design for the DTL are performed for effective beam acceleration, and the design results are in detail presented.

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MOPAB120

Beam Instrumentation for the CERN LINAC4 and PSB Half Sector Test

instrumentation, laser, emittance, proton

408

F. Roncarolo, J.C. Allica Santamaria, M. Bozzolan, C. Bracco, S. Burger, G.J. Focker, G. Guidoboni, L.K. Jensen, B. Mikulec, A. Navarro Fernandez, U. Raich, J.B. Ruiz, L. Søby, J. Tan, W. Viganò, C. Vuitton, C. Zamantzas
CERN, Geneva, Switzerland
T. Hofmann
Royal Holloway, University of London, Surrey, United Kingdom

The construction, installation and initial commissioning of CERN's LINAC4 was completed in 2016 with H⁻ ions successfully accelerated to its top energy of 160 MeV. The accelerator is equipped with a large number of beam diagnostic systems that are essential to monitor, control and optimize the beam parameters. A general overview of the installed systems and their functional specifications will be followed by a summary of the most relevant results. This includes transverse profile monitors (wire scanners, wire grids and a laser profile monitor), beam position and phase monitors (whose ToF measurements were essential for adjusting RF cavity parameters), beam loss monitors, beam current transformers and longitudinal beam shape monitors. This contribution will also cover the beam instrumentation for the so-called PSB Half Sector Test, which has been temporarily installed in the LINAC4 transfer line to study H⁻ stripping efficiency. At this facility it was possible to test the new H⁰/H⁻ beam current monitor, designed to monitor the stripping efficiency and an essential element of the beam interlock system when the LINAC4 is connected to the PSB in 2019.

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MOPAB149

Design of LCLS-II ATCA BPM System

network, undulator, FEL, controls

477

A. Young, R. Claus, J.M. D'Ewart, J.C. Frisch, G. Haller, R.T. Herbst, S. L. Hoobler, U. Legat, J.J. Olsen, R. Ruckman, L. Sapozhnikov, S.R. Smith, T. Straumann, J.A. Vásquez, M. Weaver, E. Williams, C. Xu
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S. Department of Energy under Contract Numbers DE-AC02-06CH11357
SLAC's LCLS-II is a next generation X-ray FEL that will use a CW 4 GeV superconducting linac with nominal bunch spacing of 1us will deliver both soft and hard x-ray FEL to users. In order to achieve the required performance, the SLAC Technical Innovation Directorate has developed a common hardware and firmware platform for beam instrumentation based on the ATCA crate format. We have designed a stripline and cavity BPM system based on this platform that is capable of measuring the beam position at full beam rate. The system will have a dynamic range between 1 pC to 300 pC. This paper will discuss the design of the BPM electronics, overall architecture and performance on LCLS-I.

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MOPIK016

Sub-Picosecond Beam Production for External Injection Into Plasma Experiments

gun, plasma, electron, simulation

531

O. Mete Apsimon, R. Apsimon, G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
G.X. Xia
UMAN, Manchester, United Kingdom

Funding: This work has been funded by STFC.
Applications of plasmas in accelerators benefit from short probe bunches comparable to plasma wavelength due to currently achievable plasma wake profiles. In plasma acceleration case, high capture efficiency within a narrow energy spectrum can be achieved when a sub-picosecond to femtosecond witness bunch injected behind the driver pulse at the high electric field region. A start-to-end simulation study was performed for parametric optimisation of an rf photoinjector to provide a short witness bunch for plasma applications in accelerators. An rf photoinjector is a laser-driven, high brightness and robust electron source that can provide stability and flexibility provided by today's advanced laser and rf technologies.

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MOPIK029

Energy Deposition and Activation Studies of the ESSnuSB Horn Station

target, proton, hadron, neutron

561

E. Bouquerel, E. Baussan, M. Dracos
IPHC, Strasbourg Cedex 2, France
N. Vassilopoulos
IHEP, Beijing, People's Republic of China

Funding: This project is now supported by the COST Action CA15139 Combining forces for a novel European facility for neutrino-antineutrino symmetry-violation discovery (EuroNuNet).
The ESS'SB project foresees the production of a very intense neutrino beam to enable the discovery of leptonic CP violation. In addition to the neutrinos, a copious number of muons that could be used by a future Neutrino Factory and a muon collider will also be produced at the same time. This facility will use the world's most intense pulsed spallation neutron source, the European Spallation Source (ESS) in Lund. Its LINAC is expected to be operational by 2023, producing 2 GeV protons with a power of 5 MW. The primary proton beam line completing the linear accelerator will consist of one or several accumulator rings and a proton beam switchyard. The secondary beam line producing neutrinos and muons will consist of a four-horn target station, a decay tunnel and a beam dump. To detect the produced neutrinos a far megaton scale Water Cherenkov detector will be placed at a baseline of about 500 km in one of the existing active mines in Sweden. The estimation of the energy deposited and the activation within this secondary beam line are discussed in this paper.

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MOPIK040

Value Engineering of an Accelerator Design During Construction

cavity, cryomodule, neutron, proton

592

E. Bargalló, M. Eshraqi, M. Lindroos, S. Molloy, D.C. Plostinar, A. Sunesson
ESS, Lund, Sweden
F. Gerigk
CERN, Geneva, Switzerland

Value engineering is an important part of the process of designing and realising large-scale installations such as high power accelerators. This typically occurs during the later part of the design stage of the system, however such exercises may also be requested by funding bodies at later stages in order to manage project contingency. Naturally, the later this is done, the more challenging it becomes. In this paper we report on a recently concluded Value Engineering effort at the European Spallation Source. The challenges presented by the initiation of such an exercise during the construction phase are discussed. In addition, we present and discuss the various options that we examined, and indicate the philosophy and figures of merit used to narrow down these options. The final conclusion will be presented.

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MOPIK041

Commissioning of the Stripping Foil Units for the Upgrade of the PSB H⁻ Injection System

injection, controls, electron, vacuum

595

C. Bracco, S. Burger, V. Forte, B. Goddard, G. Guidoboni, L.O. Jorat, B. Mikulec, A. Navarro Fernandez, R. Noulibos, F. Roncarolo, P. Van Trappen, W.J.M. Weterings
CERN, Geneva, Switzerland

The PSB will be extensively upgraded during the next long shutdown of the CERN accelerator complex, to double the brightness of the stored beams. The existing multi-turn injection will be replaced by a charge exchange system designed for the 160 MeV hydrogen ions provided by Linac4. Part of the injection equipment has been temporarily installed along the Linac4-to-PSB transfer line and tested with beam. This allowed to gain experience with the system, test the related diagnostics and benchmark calculations with measurements. An additional permanent stripping foil test stand is also installed right after the Linac and will be used to characterise new foils for possible future applications. The main outcomes, issues and applied or planned mitigations are presented for both installations.

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MOPIK047

Commissioning and Results of the Half-Sector Test Installation with 160 MeV H⁻ beam from Linac4

injection, operation, proton, vacuum

619

B. Mikulec, D. Aguglia, J.C. Allica Santamaria, C. Baud, C. Bracco, S. Burger, G. Guidoboni, L.O. Jorat, C. Martin, A. Navarro Fernandez, R. Noulibos, F. Roncarolo, J.L. Sanchez Alvarez, J. Tan, T. Todorcevic, P. Van Trappen, W.J.M. Weterings, C. Zamantzas
CERN, Geneva, Switzerland

During the Long Shutdown 2 (LS2) at CERN in 2019/20, the Proton Synchrotron Booster (PSB) will undergo a profound upgrade in the framework of the LHC Injector Upgrade (LIU) project involving also the connection to the new Linac4 injector. The 160 MeV Linac4 H' injection entails a complete replacement of the PSB injection section, including a stripping foil system, injection chicane, an H⁰/H' dump and novel beam instrumentation. The equivalent of half of this new injection chicane was temporarily installed in the Linac4 transfer line to evaluate the performance of the equipment and prepare controls, interlocks and applications for the connection. Outcomes of this so-called Half-Sector Test (HST) are presented in this paper.

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MOPIK057

Strategy of Beam Tuning Implementation for the SARAF MEBT and SC Linac

solenoid, quadrupole, focusing, simulation

652

P.A.P. Nghiem, D. Uriot
CEA/DSM/IRFU, France
B. Dalena, J. Dumas, N. Pichoff
CEA/IRFU, Gif-sur-Yvette, France

Beam dynamics of the MEBT and Superconducting Linac in the SARAF accelerator are being finalized. A strategy for beam tuning implementation is applied to this section, leading to specifying the complete set of error tolerances / beam measurements / correctors. A systematic and precise methodology in several steps is applied, leading to fairly distributing the error budget, from which correction schemes are studied, allowing to determine the necessary beam measurements and correctors.

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MOPIK058

Beam Dynamic Studies for the SARAF MEBT and SC Linac

quadrupole, cavity, rfq, simulation

655

J. Dumas, N. Pichoff, D. Uriot
CEA/IRFU, Gif-sur-Yvette, France
P.A.P. Nghiem
CEA/DSM/IRFU, France

The SARAF MEBT and Super Conducting Linac (SCL) transport and accelerate deuterons or protons from the RFQ to the final energy. In this report, beam dynamics studies for this section are described. A rational distribution of the different roles of the MEBT leads to defining its necessary quadrupole/rebuncher composition. This allows easy beam re-tuning following changes from the RFQ or the SC Linac. After observing evidences of beam losses mainly due to phase unhooking, efforts have been dedicated to enlarge the SCL longitudinal acceptance. A combination of cavity field phases is found so that the required final beam energy is also fulfilled.

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MOPIK068

Beam Dynamics Design Parameters for KONUS Lattices

lattice, acceleration, cavity, emittance

683

R. Tiede, H. Hähnel, U. Ratzinger
IAP, Frankfurt am Main, Germany

The 'Combined Zero-Degree Structure' ('Kombinierte Null Grad Struktur - KONUS') beam dynamics concept has been successfully applied on several linacs, some of them in routine operation since decades. However, the KONUS lattice parameters optimization is often done in a results-oriented approach, depending on the designers' experience. This paper focuses on the description of the longitudinal beam motion along one KONUS lattice period. A test lattice is used for demonstrating the potential of KONUS lattices with respect to stable, periodic beam motion with emittance growth rates similar to those of conventional designs. The main objective of this ongoing work is to derive more general rules for the parametrization of KONUS lattices.

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MOPIK095

Implementation Issues and First Results of the ESS Beam Current Monitor System

electronics, interface, ion-source, FPGA

745

H. Hassanzadegan, M.D. Donna, A. Jansson, H. Kocevar, T.J. Shea
ESS, Lund, Sweden
M. Werner
DESY, Hamburg, Germany

The BCM system of the European Spallation Source needs to measure several beam parameters including pulse profile, charge, current, pulse width and repetition frequency. Moreover, it will measure differential beam currents using several ACCT pairs along the linac. This is particularly important at low beam energies where BLMs cannot be used for measuring beam losses. Due to the ESS-specific requirements, the BCM software and firmware will be customized. Also, parts of the electronics may need to be customized to be consistent with the ESS standard electronics platform, hence facilitate maintenance and maximize synergy with other systems. Technical challenges include maintaining signal integrity and a fast response despite large variations in the sensor cable length and ambient temperature, as well as minimizing the effect of the ground voltage fluctuations. This paper gives a general overview of the design and focuses on a few technical issues that are particularly important for satisfying the performance requirements. Also, BCM test results in laboratory conditions as well as preliminary results with the ESS ion source will be presented.

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MOPIK115

A Design for 10 GeV, High Peak-Current, Tightly Focused Electron Beams at FACET-II

emittance, electron, simulation, acceleration

807

G.R. White
SLAC, Menlo Park, California, USA

Funding: This work was sponsored by the Department of Energy under Contract Number: DE-AC02-76SF00515
FACET-II will be a new test facility, starting construction in 2018 within the main SLAC Linac. Its purpose is to build on the decades-long experience developed conducting accelerator R&D at SLAC in the areas of advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. The design consists of a 135-MeV high-brightness photo-injector constructed in an off-axis injection line in Sector 10 of the SLAC Linac, two new 4-bend chicane bunch compressors installed in Sectors 11 and 14, with a third compression stage provided by the existing FACET W Chicane in Sector 20. We develop a design to deliver peak currents more than 160 kA to the Sector 20 interaction region at 10 GeV, with 10 'm-rad emittances at 2 nC bunch charge and 1.4 % rms energy spread. The Sector 20 bunch compressor is re-designed for maximum peak current throughput and minimal emittance degradation via CSR, and the FACET-II compression scheme is optimized. We present 6D start-end beam tracking simulations using Lucretia including ISR, CSR, wakefields and space charge effects.

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MOPIK117

On the Computation of Phase and Energy Gain for a Thin-Lens RF Gap Using a General Field Profile

simulation, factory, acceleration, cavity

810

C.K. Allen
ORNL, Oak Ridge, Tennessee, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract number DE-AC05-00OR22725.
The thin-lens representation for an RF accelerating gap has been well developed and is documented by Lapostolle [5], Weiss [6], Wangler [14], and others [9], [10]. These models assume that the axial electric field is both centered and symmetric so it has a cosine expansion. Presented here is a model that considers general axial fields. Both the cosine and sine transit time factors are required plus their Hilbert transforms. The combination yields a complex Hamiltonian rotating in the complex plane with the synchronous phase. The phase and energy gains are computed in the pre-gap and post-gap regions then aligned with asymptotic values of wave number. Derivations are outlined, examples are shown, and simulations presented.

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MOPIK118

Model Based Optics Studies in the MEBT Section of SNS

emittance, lattice, simulation, rfq

814

A.P. Shishlo, A.V. Aleksandrov, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA
Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan

Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC0500OR22725 with the U.S. Department of Energy.
The paper presents the beam dynamics studies for the Medium Energy Beam Transport (MEBT) section of the Spallation Neutron Source (SNS) accelerator. The analysis of measurements is based on the PyORBIT linac model. The diagnostics data includes wire scanners' profiles, slit-harp and slit-slit transverse emittances, MEBT re-bunchers calibration data, and bunch length measurements. The MEBT is a matching section between RFQ and a Drift Tube Linac (DTL). It is also a place for beam halo scraping which helps to reduce beam loss in downstream linac sections. The linac simulation code was benchmarked against the diagnostics data.

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MOPVA005

Status of the Berlin Energy Recovery Linac Project BERLinPro

gun, SRF, booster, cavity

855

M. Abo-Bakr, W. Anders, K.B. Bürkmann-Gehrlein, A.B. Büchel, P. Echevarria, A. Frahm, H.-W. Glock, F. Glöckner, F. Göbel, B.D.S. Hall, S. Heling, H.-G. Hoberg, A. Jankowiak, C. Kalus, T. Kamps, G. Klemz, J. Knedel, J. Knobloch, J. Kolbe, G. Kourkafas, J. Kühn, B.C. Kuske, J. Kuszynski, D. Malyutin, A.N. Matveenko, M. McAteer, A. Meseck, C.J. Metzger-Kraus, R. Müller, A. Neumann, N. Ohm, K. Ott, E. Panofski, F. Pflocksch, J. Rahn, M. Schmeißer, O. Schüler, M. Schuster, J. Ullrich, A. Ushakov, J. Völker
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association.
The Helmholtz-Zentrum Berlin is constructing the Energy Recovery Linac Prototype BERLinPro, a demonstration facility for the science and technology of ERLs for future light source applications. BERLinPro is designed to accelerate a high current (100 mA, 50 MeV), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. We report on the project status. This includes the completion of the building and the installation of the first accelerator components as well as the assembly of the SRF gun and GunLab beam diagnostics, which are now ready for commissioning.

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MOPVA008

Commissioning Considerations for BERLinPro

laser, diagnostics, gun, target

862

M. McAteer, M. Abo-Bakr, T. Kamps, G. Klemz, J. Kuszynski
HZB, Berlin, Germany
I. Will
MBI, Berlin, Germany

BERLinPro is an energy recovery linac project whose goal is to establish the accelerator physics knowledge and technology needed to produce 50 MeV beams with high current, low normalized emittance, and low losses. The machine will be commissioned in phases beginning in 2018, and extensive planning is underway for start-up of the machine and to prepare for measurements to verify the achievement of target beam parameters. This paper outlines the planned phases for the commissioning of the machine, details the operational modes, and gives an overview of the diagnostics available for beam-based measurements to verify the achievement of performance goals.

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MOPVA012

The Dedicated Accelerator R&D Facility Sinbad at DESY

electron, laser, experiment, acceleration

869

U. Dorda, R.W. Aßmann, K. Galaydych, W. Kuropka, B. Marchetti, D. Marx, F. Mayet, G. Vashchenko, T. Vinatier, P.A. Walker, J. Zhu
DESY, Hamburg, Germany
A. Fallahi, F.X. Kärtner, N.H. Matlis
CFEL, Hamburg, Germany

We present an overview of the dedicated R\&D facility SINBAD which is currently under construction at DESY. The facility will host multiple independent experiments on the acceleration of ultra-short electron bunches and advanced acceleration schemes. In its initial phase, SINBAD will host two experiments: AXSIS and ARES. The AXSIS collaboration aims to accelerate fs-electron bunches to 15 MeV in a THz driven dielectric structure and subsequently create X-rays by inverse Compton scattering. The first stage of the ARES experiment is to set up a 100 MeV S-band electron linac to produce ultra-short electron bunches with excellent beam arrival time stability. Once this is achieved, the electrons will be ideally suited to be injected into experiments for testing advanced accelerator concepts e.g. DLA experiments in the context of the ACHIP collaboration. In the long term, external injection into a laser driven plasma acceleration stage is targeted as well.

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MOPVA013

Application of Non-Isochronous Beam Dynamics in ERLs for Improving Energy Spread and Beam Stability

electron, acceleration, operation, recirculation

873

F. Hug
IKP, Mainz, Germany

Funding: Work supported by DFG through the PRISMA cluster of excellence EXC 1098/2014 and Research Training Group GRK 2128
Non-isochronous recirculation is the common operation mode for synchrotrons or microtrons. In such a non-isochronous recirculation scheme the recirculation paths provide a non-zero longitudinal dispersion while the accelerating field is operated at a certain phase off-crest with respect to the maximum. In few turn linacs like ERLs and in microtrons non-isochronous beam dynamics can be used to reduce the energy spread by cancelling out any rf-jitters coming from the linac cavities. To do so the longitudinal phase advance needs to be tuned to a half-integer number of oscillations in longitudinal phase space. Then the total energy spread after main linac acceleration conserves the value at injection. In addition to the improved energy spread the beam stability of few-turn recirculators can be increased as well using such a system. Such concept provides an inherent beam stability and has been introduced many years ago [*] and proven to work successfully in a few-turn recirculator already [**]. We will present beam dynamics calculations for the application of nonisochronous beam dynamics in single- and multi-turn energy recovery linacs at different longitudinal working points.
[*] H. Herminghaus, NIM. A 314 (1992) 209.
[**] F. Hug et al., Proc. of LINAC '12 (2012) 531.

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MOPVA014

Injector Linac Stability Requirements for High Precision Experiments at MESA

experiment, electron, operation, acceleration

876

F. Hug, R.G. Heine
IKP, Mainz, Germany

Funding: Work supported by DFG through the PRISMA cluster of excellence EXC 1098/2014 and Research Training Group GRK 2128
MESA is a recirculating superconducting accelerator under construction at Johannes Gutenberg-Universität Mainz. It will be used for high precision particle physics experiments in two different operation modes: external beam (EB) mode and energy recovery (ERL) mode. The operating beam current and energy in EB mode is 0.15 mA with polarized electrons at 155 MeV. In ERL mode an unpolarized beam of 1 mA at 10⁵ MeV will be available. In a later construction stage of MESA the beam current in ERL-mode shall be upgraded to 10 mA. In order to achieve high beam stability and low energy spread in recirculating operation the acceleration in the main linac sections will be done on edge of the accelerating field while the return arcs provide longitudinal dispersion. On certain longitudinal working points this can result in a setting where rf jitters from main linac do not contribute to the resulting energy spread of the final beam at all [*,**]. Then the resulting energy spread is only determined by the energy spread provided by the inector linac. Within this contribution we will investigate the requirements on the stability of the MESA injector linac MAMBO for achieving the experimental goals.
[*] H. Herminghaus, NIM. A 314 (1992) 209.
[**] F. Hug et al., Proc. of LINAC '12 (2012) 531.

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MOPVA016

ELI-NP GBS Status

laser, electron, gun, collimation

880

A. Giribono, M. Marongiu, A. Mostacci, V. Pettinacci
INFN-Roma, Roma, Italy
S. Albergo
INFN-CT, Catania, Italy
D. Alesini, M. Bellaveglia, B. Buonomo, F. Cioeta, E. Di Pasquale, G. Di Pirro, A. Esposito, A. Falone, G. Franzini, O. Frasciello, A. Gallo, S. Guiducci, S. Incremona, F. Iungo, V.L. Lollo, L. Pellegrino, L. Piersanti, S. Pioli, R. Ricci, U. Rotundo, L. Sabbatini, A. Stella, S. Tomassini, C. Vaccarezza, A. Variola
INFN/LNF, Frascati (Roma), Italy
A. Bacci, C. Curatolo, I. Drebot, V. Petrillo, A.R. Rossi, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
N. Bliss, C. Hill
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
G. Campogiani
Rome University La Sapienza, Roma, Italy
P. Cardarelli, M. Gambaccini
INFN-Ferrara, Ferrara, Italy
F. Cardelli, A. Mostacci, L. Palumbo, A. Vannozzi
University of Rome La Sapienza, Rome, Italy
F. Cardelli, L. Palumbo
INFN-Roma1, Rome, Italy
K. Cassou, K. Dupraz, A. Martens, C.F. Ndiaye, Z.F. Zomer
LAL, Orsay, France
G. D'Auria
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
L. Sabato
U. Sannio, Benevento, Italy
M. Veltri
INFN-FI, Sesto Fiorentino, Italy

New generation of Compton sources are developing in different countries to take advantage of the photon energy amplification given by the Compton backscattering effect. In this framework the Eurogammas international collaboration is producing a very high brilliance gamma source for the Nuclear Pillar of the Exterme Light Infrastructure program (ELI). At present there is a lot of effort in the mass production of all the components and in the developments and tests of the different high technology devices that will operate in the gammas beam source, like the optical recirculator and the high gradient - high average current warm C band accelerating sections. In this paper we will provide a general overview of the GBS status and of the perspectives for the future integration phase.

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MOPVA017

Electrostatic Pickup in the CNAO Injection Line

ion, pick-up, detector, proton

884

A. Parravicini, G.M.A. Calvi, E. Rojatti, C. Viviani
CNAO Foundation, Pavia, Italy

The paper concerns the electrostatic pickup (PUB) installed in the injection line of the CNAO, the Italian facility for Oncological Hadrontherapy. The PUB has been designed with the purpose of having a continuous and non-interceptive measurement of the beam transverse position short upstream the injection in the synchrotron. Detector commissioning has not been immediate since a number of primary ions and secondary electrons fall on the PUB electrodes in many configurations, resulting in a significantly distorted signal. After the identification, and consequent rejection, of a few circumstances where the PUB cannot work properly, the commissioning proceeded on a twofold way, designing a mechanical shield to stop ions before hitting the electrodes and developing an advanced data-analysis algorithm to go beyond the signal distortion. The use of the new algorithm was sufficient to make the PUB successfully working and, after a proper calibration with upstream and downstream profile monitors, the PUB started to provide the expected results. The PUB is working as a watch-dog since January 2016. Details on the data-analysis algorithm and first year measurements are discussed in the paper.

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MOPVA019

60 pC Bunch Charge Operation of the Compact ERL at KEK

operation, emittance, laser, cavity

890

T. Miyajima, K. Harada, Y. Honda, E. Kako, R. Kato, T. Miura, N. Nakamura, T. Obina, M. Shimada, R. Takai, K. Umemori, M. Yamamoto
KEK, Ibaraki, Japan
R. Hajima, R. Nagai
QST, Tokai, Japan
T. Hotei
Sokendai, Ibaraki, Japan
N. Nishimori
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

The compact ERL (cERL) at KEK was operated in March 2017 to demonstrate generation, acceleration and transportation of the target bunch charge of 60 pC without energy recovery. However, the maximum bunch charge was limited to 40 pC due to the limitation of the excitation laser power. For the bunch charge of 40 pC, the bunch length and the normalized emittance were measured in the injector diagnostic line. The results of the bunch length measurement gave good agreement with the values that had been obtained by model simulation. The measured normalized rms emittances for 40 pC were 0.9 to 2.4 mm mrad, and they were lager than the design value of 0.6 mm mrad. To achieve the design emittance, we have studied the source of the emittance growth for the bunch charge of 40 pC.

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MOPVA020

S2E Simulation of an ERL-Based High-Power EUV-FEL Source for Lithography

FEL, electron, simulation, injection

894

N. Nakamura, R. Kato, T. Miyajima, M. Shimada
KEK, Ibaraki, Japan
R. Hajima
QST, Tokai, Japan
T. Hotei
Sokendai, Ibaraki, Japan

An energy recovery linac(ERL)-based free electron laser(FEL) is a possible candidate of a high-power EUV source for lithography. The ERL can provide a high-current and high-quality electron beam for the high-power FEL and also greatly reduce the dumped beam power and activation compared to ordinary linacs. An ERL-based EUV-FEL source has been designed using available technologies and resources*. For this design, we perform Start-to-End(S2E) simulation from the electron gun to the exit of the decelerating main linac to track the electron beam parameters and to evaluate the FEL performance. The electron bunches from the injector are off-crest accelerated to 800 MeV and compressed in the 1st arc and/or chicane to obtain a high-peak current for high FEL output. After the undulator section for SASE FEL, they are decompressed in the 2nd arc and then decelerated in the main linac to optimize the energy spread or the energy recovery efficiency. This paper will present the S2E simulation for the designed EUV-FEL source.
* N. Nakamura et al., Proc. of ERL2015, Stony Brook, NY, USA, pp.4-9.

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MOPVA033

A Compact Thermionic RF Injector with RF Bunch Compression fed by a Quadrupole-Free Mode Launcher

gun, cathode, electron, undulator

924

F. Toufexis, V.A. Dolgashev, C. Limborg-Deprey, S.G. Tantawi
SLAC, Menlo Park, California, USA

Funding: This project was funded by U.S. Department of Energy under Contract No. DE-AC02-76SF00515, and the National Science Foundation under Contract No. PHY-1415437.
We present a design for a compact X-Band RF thermionic injector consisting of two iris-loaded accelerator structures. Both structures are fed by a single quadrupole-free TM01 mode launcher. In the first structure the electron bunches are extracted from a thermionic cathode. The second structure creates an energy chirp in the bunch for its further ballistic compression. This injector can produce short electron bunches without the need for a magnetic bunch compressor. We are developing this injector as part of a linac-based 91.392 GHz RF power source, which further comprises a booster linac and a mm-wave decelerator structure that extracts 91.392 GHz RF power from the electron beam. This source will be used to power a short-period RF undulator with 1.75 mm period*.
* F. Toufexis and S.G. Tantawi, A 1.75 mm Period RF-Driven Undulator, these proceedings.

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MOPVA037

Development and Commissioning of the Doppler-Shift Unit for the Measurement of the Ion Species Fractions and Beam Energy of the ESS Proton Source

proton, coupling, software, optics

936

C.A. Thomas, T.J. Shea
ESS, Lund, Sweden
J. Fils
GSI, Darmstadt, Germany
Y. Lussignol, P. Mattei
CEA/DSM/IRFU, France
Ø. Midttun
University of Bergen, Bergen, Norway
L. Neri
INFN/LNS, Catania, Italy
F. Senée, O. Tuske
CEA/IRFU, Gif-sur-Yvette, France

ESS proton source is in going to be soon delivered to the ESS project. In order to qualify the source, a series of beam instrumentation diagnostics have been designed and produced. In particular, a specific spectrograph dedicated to the fraction species measurement is currently commissioned. This instrument not only is capable of measuring the fraction species produced by the source, but also it can measure their energy and energy spread, the mass of the different species, and additional spectral rays coming from the gas species in presence in the vacuum chamber. We present in this paper the commissioning of this instrument, the Doppler Shift unit, dedicated to the measurement of the fraction species.

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MOPVA038

Manufacturing Status of the IFMIF LIPAc SRF Linac

cryomodule, vacuum, SRF, cavity

939

N. Bazin, P. Carbonnier, P. Contrepois, J. Plouin, B. Renard
CEA/DSM/IRFU, France
C. Boulch, A. Bruniquel, J.K. Chambrillon, G. Devanz, P. Hardy, H. Jenhani, N. N'Doye, O. Piquet, A. Riquelme, D. Roudier
CEA/DRF/IRFU, Gif-sur-Yvette, France
P. Charon, S. Chel, G. Disset, J. Relland
CEA/IRFU, Gif-sur-Yvette, France
D. Regidor, F. Toral
CIEMAT, Madrid, Spain

This paper gives the fabrication status of the IFMIF cryomodule. This cryomodule will be part of the Linear IFMIF Prototype Accelerator (LIPAc) whose construction is ongoing at Rokkasho, Japan. It is a full scale of one of the IFMIF accelerator, from the injector to the first cryomodule. The cryomodule contains all the necessary equipment to transport and accelerate a 125 mA deuteron beam from an input energy of 5 MeV up to the output energy of 9 MeV. It consists of a horizontal vacuum tank of around 6 m long, 3 m high and 2.0 m wide, which includes 8 superconducting HWRs for beam acceleration, working at 175 MHz and at 4.45 K, 8 Power Couplers to provide RF power to cavities up to 70 kW CW in LIPAc case and 200 kW CW in IFMIF case, and 8 Solenoid Packages as focusing elements.

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MOPVA041

Vertical Test Results on ESS Medium and High Beta Elliptical Cavity Prototypes Equipped with Helium Tank

cavity, radiation, cryomodule, background

948

E. Cenni
CEA/IRFU, Gif-sur-Yvette, France
P. Bosland, G. Devanz, F. Éozénou, X. Hanus, L. Maurice, F. Peauger, J. Plouin, D. Roudier, C. Servouin
CEA/DSM/IRFU, France
G. Costanza
Lund University, Lund, Sweden
C. Darve
ESS, Lund, Sweden

The ESS elliptical superconducting Linac consists of two types of 704.42 MHz cavities, medium and high beta, to accelerate the beam from 216 MeV (spoke cavity Linac) up to the final energy at 2 GeV. The last Linac optimization, called Optimus+, has been carried out taking into account the limitations of SRF cavity performance (field emission). The medium and high-beta parts of the Linac are composed of 36 and 84 elliptical cavities, with geometrical beta values of 0.67 and 0.86 respectively. This work presents the latest vertical test results on ESS medium and high beta elliptical cavity prototypes equipped with helium tank. We describe the cavity preparation procedure from buffer chemical polishing to vertical test.

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MOPVA046

120kW RF Power Input Couplers for BERLinPro

booster, cavity, coupling, SRF

960

B.D.S. Hall, V. Dürr, F. Göbel, J. Knobloch, A. Neumann
HZB, Berlin, Germany

The 50-MeV, 100-mA energy-recovery-linac (ERL) demonstration facility BERLinPro is currently undergoing construction at HZB. The high power injection system, that will deliver a beam at 6.5MeV, is split into a 1.4 cell SRF Photo injector and three Cornell-style 2-cell boosters. The injector and two of the booster cavities will provide about 2MeV each and must handle up to 220 kW of beam loading. New, cERL-based 115-kW high power couplers needed for the cavities' twin coupler system have begun manufacture. The design, optimization and manufacturing considerations of these couplers are presented.

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MOPVA049

First Commissioning of an SRF Photo-Injector Module for BERLinPro

cavity, cathode, SRF, solenoid

971

A. Neumann, A. Burrill, D. Böhlick, A.B. Büchel, M. Bürger, P. Echevarria, A. Frahm, H.-W. Glock, F. Göbel, S. Heling, K. Janke, T. Kamps, S. Keckert, S. Klauke, G. Klemz, J. Knobloch, G. Kourkafas, J. Kühn, O. Kugeler, N. Ohm, E. Panofski, H. Plötz, S. Rotterdam, M. Schenk, M.A.H. Schmeißer, M. Schuster, H. Stein, Y. Tamashevich, J. Ullrich, A. Ushakov, J. Völker
HZB, Berlin, Germany
A. Matheisen, M. Schmökel
DESY, Hamburg, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association.
Helmholtz-Zentrum Berlin (HZB) is currently building an high average current superconducting ERL to demonstrate ERL operation with low normalized beam emittance of 1 mm·mrad at 100mA and short pulses of about 2 ps. For the injector section a series of SRF photoinjector cavities is being developed. The medium power prototype presented here features a 1.4 x λ/2 cell SRF cavity with a normal-conducting, high quantum efficiency CsK2Sb cathode, implementing a modified HZDR-style cathode insert. This injector potentially allows for 6 mA beam current at up to 3.5 MeV kinetic energy. In this contribution, the first RF commissioning results of the photo-injector module will be presented and compared to the level of performance during the cavity production and string assembly process.

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MOPVA054

High Power RF Coupler for the CW-Linac Demonstrator at GSI

cavity, Windows, simulation, ion

990

M. Heilmann, W.A. Barth, S. Yaramyshev
GSI, Darmstadt, Germany
M. Amberg, M. Basten, R. Blank, M. Busch, F.D. Dziuba, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany
K. Aulenbacher
IKP, Mainz, Germany
K. Aulenbacher, W.A. Barth, V. Gettmann, M. Miski-Oglu
HIM, Mainz, Germany
W.A. Barth, S. Yaramyshev
MEPhI, Moscow, Russia

The planned super-heavy element (SHE) research project investigates heavy ions near the coulomb barrier in future experiments. A superconducting (sc) continuous wave (cw) CH-Linac Demonstrator was developed and installed behind the High Charge State Injector (HLI) at GSI Darmstadt, Germany. In future the advanced cw-LINAC setup, with several CH-cavities, will accelerates the heavy ion beam from HLI with an energy of 1.4 MeV/u up to 3.5 - 7.3 MeV/u. The RF power of several kW will be coupled capacitively into the CH-cavities with minimal reflection at an operation frequency of 217 MHz. Two ceramic windows (Al2O3) are installed inside the RF coupler, to reduce the premature contamination of the cavity and as an additional vacuum barrier. The CH-cavity will be operated at cryogenic temperature (4 K) and will be increased to room temperature along the RF coupler. The optimally adapted RF coupler design, providing minimal RF losses and simultaneously maximal performance, was optimized by electromagnetic simulations. An RF coupler design with a reflection-free RF adaptor as well as the temperature distribution along the coupler will be presented.

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MOPVA058

Commissioning and Operation Experience of the 3.9 GHz System in the EXFEL Linac

cavity, operation, LLRF, klystron

999

C.G. Maiano, J. Branlard, M. Hüning, M. Omet, P. Pierini, E. Vogel
DESY, Hamburg, Germany
A. Bosotti, R. Paparella, P. Pierini, D. Sertore
INFN/LASA, Segrate (MI), Italy

The European X-ray Free Electron Laser (EXFEL) injector linac hosts a 3.9~GHz module (AH1) for beam longitudinal phase space manipulation after the first acceleration stage, in order for the linac to deliver the high current beams with sufficiently low emittance for the production of 1 Angstrom FEL light to the experimental users. The module was technically commissioned in December 2015 and operated well above its nominal performances during the Injector Run from January to July 2016. Its operation has restarted in January 2017 with the startup of the whole facility, and the system met the design beam specifications after the bunch compression stages. A brief review of the commissioning and first operation experience of the RF system are presented here.

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MOPVA066

Limits for the Operation of the European XFEL 3.9 GHz System in CW Mode

cavity, operation, cryomodule, laser

1023

P. Pierini, A. Bosotti, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
J. Branlard, D. Kostin, C.G. Maiano, W.-D. Möller, P. Pierini, D. Reschke, J.K. Sekutowicz, E. Vogel
DESY, Hamburg, Germany

Future upgrades of the European XFEL (EXFEL) facility may require driving the linac at higher duty factor, possibly extending to CW mode at reduced gradients. A preliminary analysis for the accelerator modules has been presented in the EXFEL TDR, but no precise assessment has been performed so far for the present 3.9 GHz system design. By making use of data collected during the commissioning and operation phase of the EXFEL injector system, we discuss here an estimate for the limits of CW operation of the present system and a plan for its possible experimental verification with existing available cavities and the EXFEL spare module.

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MOPVA074

Fabrication of Superconducting QWR at MHI-MS

cavity, SRF, superconducting-RF, niobium

1037

N. Shigeoka, H. Hara, A. Miyamoto, K. Sennyu, T. Yanagisawa
MHI-MS, Kobe, Japan
O. Kamigaito, K. Ozeki, N. Sakamoto, K. Suda, Y. Watanabe, K. Yamada
RIKEN Nishina Center, Wako, Japan

Mitsubishi Heavy Industries Mechatronics Systems, Ltd. (MHI-MS), a subsidiary campany of MHI, took over MHI's accelerator business on October 1, 2015, and has been developing the business. MHI-MS is manufacturing the prototype Superconducting QWR for RIKEN Superconducting linac project. MHI-MS has dedicated surface treatment facilities for superconducting cavities, the QWR will be treated using this facilities. In this presentation, recent progress will be reported.

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MOPVA087

Low Betta Superconducting Cavity for the New Injector Linac for Nuclotron-NICA

cavity, simulation, multipactoring, accelerating-gradient

1058

M. Gusarova, T.A. Bakhareva, M.V. Lalayan, S.V. Matsievskiy, N.P. Sobenin, D.V. Surkov, K.V. Taletskiy, V. Zvyagintsev
MEPhI, Moscow, Russia
A.A. Bakinowskaya, V.S. Petrakovsky, A.I. Pokrovsky, D.A. Shparla
Physical-Technical Institute of the National Academy of Sciences of Belarus, Minsk, Belarus
A.V. Butenko, G.V. Trubnikov
JINR/VBLHEP, Dubna, Moscow region, Russia
V. Zvyagintsev
TRIUMF, Vancouver, Canada

The results of the RF, mechanical and multipactor discharge simulations of the 162 MHz quarter wave resonator (QWR) for New Superconducting Injector Linac for Nuclotron-NICA are presented. Cavity design in conjunction with manufacturing features is discussed.

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MOPVA088

Medium Betta Superconducting Cavity for the New Injector Linac for Nuclotron-NICA

cavity, simulation, multipactoring, accelerating-gradient

1061

M. Gusarova, M.V. Lalayan, N.P. Sobenin, D.V. Surkov, K.V. Taletskiy
MEPhI, Moscow, Russia
A.A. Bakinowskaya, V.S. Petrakovsky, A.I. Pokrovsky, D.A. Shparla
Physical-Technical Institute of the National Academy of Sciences of Belarus, Minsk, Belarus
A.V. Butenko, G.V. Trubnikov
JINR/VBLHEP, Dubna, Moscow region, Russia

The results of the electrodynamical and multipactor discharge simulations of the medium betta superconducting cavity for New Superconducting Injector Linac for Nuclotron-NICA are presented. Different designs of CH and Spoke cavities are compared and the optimal one is chosen.

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MOPVA090

ESS Superconducting RF Collaboration

cryomodule, cavity, SRF, proton

1068

C. Darve, H. Danared, N. Elias, N.F. Hakansson, M. Lindroos, C.G. Maiano, F. Schlander
ESS, Lund, Sweden
F. Ardellier, P. Bosland
CEA/DRF/IRFU, Gif-sur-Yvette, France
S. Bousson, G. Olry
IPN, Orsay, France
M. Ellis, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
L. Hermansson, R.J.M.Y. Ruber
Uppsala University, Uppsala, Sweden
P. Michelato, D. Sertore
INFN/LASA, Segrate (MI), Italy

The European Spallation Source (ESS) project is a neutron-scattering facility, currently under construction by a partnership of at least 17 European countries, with Sweden and Denmark as host nations. The ESS was designated a European Research Infrastructure Consortium, or ERIC, by the European Commission in October of 2015. Scientists and engineers from 50 different countries are members of the workforce in Lund who participate in the design and construction of the European Spallation Source. In complement to the local workforce, the superconducting RF linear accelerator is being prototyped and will be constructed based on a collaboration with European institutions: CEA-Saclay, CNRS-IPN Orsay, INFN-LASA, STFC-Daresbury, Uppsala and Lund Universities. After a description of the ESS collaborative project and its in-kind model for the SRF linac, this article will introduce the linac component first results.

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MOPVA106

Experimental Studies of Asymmetric Dual Axis Cavity for Energy Recovery LINAC

cavity, electron, luminosity, radiation

1105

I.V. Konoplev, A.J. Lancaster, K. Metodiev, A. Seryi
JAI, Oxford, United Kingdom
R. Ainsworth
Fermilab, Batavia, Illinois, USA
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

Funding: The Leverhulme Trust via International Network Grant (IN-2015-012).
Increasing the beam charge and repetition rate leads to appearance of beam break-up instabilities in conventional ERLs. At this stage the highest current, from the SRF ERL, is around 300mA. A single turn, dual axis, compact Asymmetric Energy Recovery LINAC (AERL) was proposed. The concept assumes the use of electron beams with energies up to 300 MeV and peak currents >1A, enabling the generation of high flux EUV/X-rays and THz radiation using conventional approaches. System allows beam to be transported through each stage i.e. the acceleration, interaction and deceleration only once partially removing the feedback thus increasing the instability start current. This further improved by tuning the individual cells allowing only operating mode to be uniform inside the cavity. We present the studies of 7 cells, aluminium alloy prototype of the cavity and discuss the experimental results. We show that HOMs excited on the different axis have different R/Q factors and show the field structures of operating mode and HOMs. The experimental results observed are in good agreement with theoretical predictions and the full scale copper prototype is demonstrated.

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MOPVA115

Status and Challenges of Vertical Electro-Polishing R&D at Cornell

cathode, cavity, niobium, SRF

1115

F. Furuta, M. Ge, T. Gruber, D.L. Hall, J.J. Kaufman, M. Liepe, R.D. Porter, J. Sears
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi
MGH, Hyogo-ken, Japan
T.D. Hall, M.E. Inman, R. Radhakrishnan, S.T. Snyder, E.J. Taylor
Faraday Technology, Inc., Clayton, Ohio, USA
H. Hayano, S. Kato, T. Saeki
KEK, Ibaraki, Japan

Advanced Vertical Electro-Polishing (VEP) R&D for SRF Niobium cavities continues at Cornell's SRF group. One focus of this work is new EP cathode development in collaboration with KEK and Marui Galvanizing Co. Ltd (Marui) in Japan, and another focus is on HF free or acid free VEP protocols in collaboration with Faraday Technology Inc. The outcomes of these activities could be a significant cost reduction and an environmentally-friendlier VEP, which would be a breakthrough for future large scale EP applications on SRF cavities. Here we give a status update and report latest results from these R&D activities.

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MOPVA122

Microphonics Studies of the CBETA Linac Cryomodules

cavity, cryomodule, operation, SRF

1138

N. Banerjee, J. Dobbins, F. Furuta, D.L. Hall, G.H. Hoffstaetter, M. Liepe, P. Quigley, E.N. Smith, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work was performed through the support of NYSERDA (New York State Energy Research and Development Agency).
The Cornell BNL ERL Test Accelerator (CBETA) incorporates two SRF linacs; one for its injector and another for the energy recovery loop. Microphonics in both the cryomodules play a crucial role in determining the energy stability of the electron beam in high current operation. We have measured vibrations and frequency detuning of the SRF cavities and determined that the cryogenic system is the major source of microphonics in both cryomodules. In this paper we discuss these measurements and demonstrate an Active Microphonics Compensation system implemented using fast piezo-electric tuners which we incorporated in our Low Level RF control system to be used in routine operation.

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MOPVA124

Effectiveness of Chemical Treatments for Reducing the Surface Roughness of Nb3Sn

niobium, SRF, klystron, cavity

1145

R.D. Porter, F. Furuta, D.L. Hall, M. Liepe, J.T. Maniscalco
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: DOE DE-SC008431, NSF-PHY 1549132, NSF DMR-1120296
Current Niobium-3 Tin (Nb3Sn) superconducting radio-frequency (SRF) accelerator cavities have rougher surfaces than conventional electropolished Niobium accelerator cavities. The surface roughness can cause enhancement of the surface magnetic field, pushing it beyond the critical field. If this occurs over a large enough area it can cause the cavity to quench. The surface roughness may cause other effects that negatively impact cavity quality factor (Q) performance. Reducing surface roughness of Nb3Sn cavities may be necessary to achieve higher gradient with high Q. Current chemical treatments for reducing the surface roughness of Niobium are challenging for Nb3Sn: the Nb3Sn layer is only ~2 um thick while it is difficult to remove less than 1 mu uniformly with most chemical treatments. This paper presents measurements of the surface roughness before and after Buffered Chemical Polish, Electropolishing and oxipolishing.

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MOPVA127

Vertical Test Results for the LCLS-II 1.3 GHz First Article Cavities

cavity, cryomodule, SRF, FEL

1152

A. Burrill, D. Gonnella, M.C. Ross
SLAC, Menlo Park, California, USA
G.K. Davis, A.D. Palczewski, L. Zhao
JLab, Newport News, Virginia, USA
A. Grassellino, O.S. Melnychuk
Fermilab, Batavia, Illinois, USA

The LCLS-II project requires 35 1.3 GHz cryomodules to be installed in the accelerator in order to deliver a 4 GeV electron beam to the undulators hall. These 35 cryomodules will consist of 8 1.3 GHz TESLA style SRF cavities, a design most recently used for the XFEL project in Hamburg, Germany. The cavity design has remained largely unchanged, but the cavity treatment has been modified to utilize the nitrogen doping process to allow for Quality factors in excess of 3x10¹⁰ at 16 MV/m, the designed operating gradient of the cavities in the CM. Two industrialized vendors are producing most of the SRF cavities for these cryomodules; and the performance of the first article cavities, 16 from each vendor, will be reported on in this paper.

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MOPVA131

Status of the LCLS-II Accelerating Cavity Production

cavity, status, controls, target

1164

F. Marhauser, E. Daly, J.A. Fitzpatrick, A.D. Palczewski, J.P. Preble, K.M. Wilson
JLab, Newport News, Virginia, USA
A. Burrill, D. Gonnella
SLAC, Menlo Park, California, USA
C.J. Grimm
Fermilab, Batavia, Illinois, USA

Funding: Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 with supplemental funding from the LCLS-II Project U.S. DOE Contract No. DE-AC02-76SF00515.
Cavity serial production for the LCLS-II 4 GeV CM SRF linac has started. A quantity of 266 accelerating cavities has been ordered from two industrial vendors. Jefferson Laboratory leads the cavity procurement activities for the project and has successfully transferred the Nitrogen-Doping process to the industrial partners in the initial phase, which is now being applied for the production cavities. We report on the results from vendor qualification and the status of the cavity production for LCLS-II.

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MOPVA133

Optimization of the RF Cavity Heat Load and Trip Rates for CEBAF at 12 GeV

cavity, operation, electron, SRF

1170

H. Zhang, A. Freyberger, G.A. Krafft, Y. Roblin
JLab, Newport News, Virginia, USA
B. Terzić
ODU, Norfolk, Virginia, USA

Funding: Work supported by the Department of Energy under Contract No. DE-AC05-06OR23177
The Continuous Electron Beam Accelerator Facility at JLab has 200 RF cavities in the north linac and the south linac respectively after the 12 GeV upgrade. The purpose of this work is to simultaneously optimize the heat load and the trip rate for the cavities and to reconstruct the pareto-optimal front in a timely manner when some of the cavities are turned down. By choosing an efficient optimizer and strategically creating the initial gradients, the pareto-optimal front for no more than 15 cavities down can be re-established within 20 seconds.

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TUYA1

Linac4: From Initial Design to Final Commissioning

quadrupole, proton, emittance, DTL

1217

A.M. Lombardi
CERN, Geneva, Switzerland

This talk reviews the design, construction, and commissioning effort of CERN's new proton linear accelerator, Linac4, which has recently been commissioned and which is presently undergoing a reliability run. Linac4 will be connected to the LHC proton injector chain during the next long LHC shut down (LS2) and will then replace the ageing Linac2.

Slides TUYA1 [30.159 MB]

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TUOBA1

Beam Commissioning Results of the CSNS Linac

DTL, rfq, cavity, quadrupole

1223

J. Peng, Y.W. An, S. Fu, L. Huang, M.Y. Huang, Y. Li, Z.P. Li, S. Wang, S.Y. Xu, Y. Yuan
IHEP, Beijing, People's Republic of China
M.T. Li, Y.D. Liu
CSNS, Guangdong Province, People's Republic of China

The China Spallation Neutron Source(CSNS) accelera-tor systems is designed to deliver a 1.6GeV, 100kW pro-ton beam to a solid metal target for neutron scattering research. It consists of a 50keV H⁻ Ion Source, a 3MeV Radio Frequency Quadrupole (RFQ), an 80MeV Drift Tube Linac (DTL), and a 1.6GeV Rapid-cycling Synchro-tron (RCS). The beam commissioning has been started since April 2015. The Front End and three of the four DTL tanks have been commissioned, while the last tank and the RCS will be commissioned at the autumn this year. At the end of the DTL3, beam has been accelerated to 61MeV with nearly 100% transmission, other parame-ters such as peak current, transverse emittance and beam orbit have reached the design goal. Results and status of the beam commissioning program will be presented.
*This work is supported by National Natural Science Foundation of China (11505101).
**E-mail:pengjun@ihep.ac.cn

Slides TUOBA1 [4.272 MB]

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TUOBB1

Experimental Demonstration of Energy-Chirp Reduction by a Plasma Dechirper

plasma, electron, laser, experiment

1258

Y.P. Wu, Z. Cheng, Y.-C. Du, J.F. Hua, W. Lu, C.H. Pai, J. Zhang, S.Y. Zhou, Z. Zhou
TUB, Beijing, People's Republic of China

The first experimental study is presented using a low density plasma dechirper to reduce a correlated energy chirp from the 41.5-MeV, 500-fs (RMS) beam at the linac in Tsinghua University. The plasma dechirper operates through the interaction of the electron bunch with its near linear self-wake to dechirp itself, leading to a reduction in energy spread. The experimental results demonstrate that the projected FWHM energy spread of the beam can be reduced from 1.2% to 0.9% with a 12 mm long plasma dechirper, which are in good agreement with full 3D PIC simulations. Theoretical analyses and simulations indicate that by optimizing the plasma density and length, the plasma dechirper can also be used to completely remove the characteristic energy chirp of the ultra-short high-current bunch generated from plasma based accelerator, such that its energy spread can be reduced from one percent level to 0.1 percent level[*]. Application of such a simple and effective method can significantly improve the beam quality and provide the path to realize the future compact free electron lasers and colliders driven by plasma based accelerators.
[*] Y. P. Wu. A plasma dechirper for electron and positron beams in plasma-based accelerators, to be submitted to Scientific Reports

Slides TUOBB1 [10.555 MB]

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TUZB1

Final Results From the Clic Test Facility (CTF3)

operation, acceleration, emittance, beam-loading

1269

R. Corsini
CERN, Geneva, Switzerland

The unique CLIC TEST Facility (CTF3) has been built more than a decade ago to demonstrate the feasibility of the CLIC two beam acceleration scheme. The emphasis was one the high current drive beam generation using a fully loaded highly efficient linac and a complex combination scheme to increase beam current and bunch repetition frequency. This drive beam has been used for deceleration experiments and two beam acceleration. A wealth of relevant results for accelerator physics even beyond CLIC has been obtained and will be presented. The rf to beam efficiency of the linac exceeds 95%, after combination the 28 A drive beam with 12 GHz bunch repetition rate has been used to extract more than 50% of its energy producing 1.3 GW of 12 GHz power as well as performing two beam acceleration at 12 GHz with gradients up to 150 MV/m.

Slides TUZB1 [23.702 MB]

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TUOCB3

CBETA - Cornell University Brookhaven National Laboratory Electron Energy Recovery Test Accelerator

electron, permanent-magnet, acceleration, gun

1285

D. Trbojevic, S. Bellavia, J.S. Berg, M. Blaskiewicz, S.J. Brooks, K.A. Brown, W. Fischer, F.X. Karl, C. Liu, G.J. Mahler, F. Méot, R.J. Michnoff, M.G. Minty, S. Peggs, V. Ptitsyn, T. Roser, P. Thieberger, N. Tsoupas, J.E. Tuozzolo, F.J. Willeke, H. Witte
BNL, Upton, Long Island, New York, USA
N. Banerjee, J. Barley, A.C. Bartnik, I.V. Bazarov, D.C. Burke, J.A. Crittenden, L. Cultrera, J. Dobbins, B.M. Dunham, R.G. Eichhorn, S.J. Full, F. Furuta, R.E. Gallagher, M. Ge, B.K. Heltsley, G.H. Hoffstaetter, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, W. Lou, C.E. Mayes, J.R. Patterson, P. Quigley, D.M. Sabol, D. Sagan, J. Sears, C.H. Shore, E.N. Smith, K.W. Smolenski, V. Veshcherevich, D. Widger
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
D. Douglas
JLab, Newport News, Virginia, USA
D. Jusic, J.R. Patterson
Cornell University, Ithaca, New York, USA

Funding: New York State Energy Research and Development Authority (NYSERDA)
Cornell's Lab of Accelerator-based Sciences and Education (CLASSE) and the Collider Accelerator Department (BNL-CAD) are developing the first SRF multi-turn energy recovery linac with Non-Scaling Fixed Field Alternating Gradient (NS-FFAG) racetrack. The existing injector and superconducting linac at Cornell University are installed together with a single NS-FFAG arcs and straight section at the opposite side of the the linac to form an Electron Energy Recovery (ERL) system. Electron beam from the 6 MeV injector is injected into the 36 MeV superconducting linac, and accelerated by four successive passes: from 42 MeV up to 150 MeV using the same NS-FFAG structure made of permanent magnets. After the maximum energy of 150 MeV is reached, the electron beam is brought back to the linac with opposite Radio Frequency (RF) phase. Energy is recovered and reduced to the initial value of 6 MeV with 4 additional passes. There are many novelties: a single NS-FFAG structure, made of permanent magnets, brings electrons with four different energies back to the linac. A new adiabatic NS-FFAG arc-to-straight section merges 4 separated orbits into a single orbit in the straight section.

Slides TUOCB3 [41.888 MB]

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TUPAB004

Progress of 7-GeV SuperKEKB Injector Linac Upgrade and Commissioning

positron, gun, injection, electron

1300

K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, H. Ego, A. Enomoto, Y. Enomoto, S. Fukuda, Y. Funahashi, T. Higo, H. Honma, N. Iida, M. Ikeda, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, M. Kawamura, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, H. Nakajima, K. Nakao, T. Natsui, M. Nishida, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, I. Satake, D. Satoh, M. Satoh, Y. Seimiya, A. Shirakawa, H. Sugimoto, H. Sugimura, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, N. Toge, Y. Yano, K. Yokoyama, M. Yoshida, R. Zhang, X. Zhou
KEK, Ibaraki, Japan

KEK injector linac has delivered electrons and positrons for particle physics and photon science experiments for more than 30 years. It is being upgraded for the SuperKEKB project, which aims at a 40-fold increase in luminosity over the previous project KEKB, in order to increase our understanding of new physics beyond the standard model of elementary particle physics. SuperKEKB asymmetric electron and positron collider with its extremely high luminosity requires a high current, low emittance and low energy spread injection beam from the injector. Electron beams will be generated by a new type of RF gun, that will provide a much higher beam current to correspond to a large stored beam current and a short lifetime in the ring. The positron source is another major challenge that enhances the positron bunch intensity from 1 to 4 nC by increasing the positron capture efficiency, and the positron beam emittance is reduced from 2000 micron to 20 micron in the vertical plane by introducing a damping ring, followed by the bunch compressor and energy compressor. The recent status of the upgrade and beam commissioning is reported.

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TUPAB005

Investigation of Beam Variation and Emittance Growth Simulation With Both Misalignments and the Beam Jitter for SuperKEKB Injector Linac

emittance, electron, simulation, quadrupole

1304

Y. Seimiya, K. Furukawa, T. Higo, F. Miyahara, M. Satoh, T. Suwada
KEK, Ibaraki, Japan

Funding: This work was supported by JSPS KAKENHI Grant Number 16K17545.
The SuperKEKB is e⁺/e⁻ circular collider for high luminosity, 8Â¥times10³⁵ as a target value. For the high luminosity, the injector linac is required to transport low emittance high-charged electron beam and positron beam to the ring. A charged beam with an offset from a center of cavity is affected by the wakefield depending on both the offset size in the cavity and longitudinal particle position in the beam. The wakefield causes emittance growth. This growth can be suppressed by appropriate orbit control so as to cancel the wakefield effect of the cavities in total. On the other hands, the beam variation in 6-dimensional phase space also induces the emittance growth. Emittance growth by both misalignments and 6-dimensional beam jitter was evaluated by particle tracking simulation. Investigation of beam jitter and drift was also performed by correlation analysis between beam position and measured parameter, charge or temperature.

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TUPAB008

CEPC Linac Design and Beam Dynamics

positron, electron, target, quadrupole

1315

C. Meng, Y.L. Chi, X.P. Li, G. Pei, S. Pei, D. Wang, J.R. Zhang
IHEP, Beijing, People's Republic of China

Circular Electron-Positron Collider (CEPC) is a 100 km ring e⁺ e⁻ collider for a Higgs factory, which is organized and led by the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences (CAS) in collaboration with a number of institutions from various countries. The linac of CEPC is a normal con-ducting S-band linac with frequency in 2856.75 MHz and provide electron and positron beam at an energy up to 10 GeV with bunch charge in 1.0 nC and repetition frequency in 100 Hz. The linac scheme will be detailed discussed in this paper, including electron bunching system, positron source design, and main linac. Positrons are generated using a 4 GeV electron beam with bunch charge 10 nC hit tungsten target and the positron source design are presented. The beam dynamic results with longitudinal short Wakefield, transverse Wakefield and errors are presented.

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TUPAB009

Design Study on CEPC Positron Damping Ring and Bunch Compressor

damping, positron, emittance, injection

1318

D. Wang, Y.L. Chi, J. Gao, X.P. Li, C. Meng, J.R. Zhang
IHEP, Beijing, People's Republic of China
G. Pei
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

The primary purpose of CEPC damping ring is to reduce the transverse phase spaces of positron beam to suitably small value at the beginning of Linac and also adjust the time structure of positron beam for reinjection into the Linac. Longitudinal bunch length control was provided to minimize wake field effects in the Linac by a bunch compressor system after the damping ring. Both designs for damping ring and bunch compressor were discussed in this paper.

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TUPAB010

High-Gradient Breakdown Studies of X-Band Choke-Mode Structures

cavity, operation, collider, linear-collider

1322

X.W. Wu, H.B. Chen, J. Shi, H. Zha
TUB, Beijing, People's Republic of China
T. Abe, T. Higo, S. Matsumoto
KEK, Ibaraki, Japan

As an alternative design for Compact Linear Collider (CLIC) main accelerating structures, X-band choke-mode damped structures had been studied for several years. However, the performance of choke-mode cavity under high power is still in lack of research. Two standing-wave single-cell choke-mode damped accelerating structures working at 11.424 GHz and one reference structure without choke were designed, manufactured, low-power measured, and tuned by accelerator group at Tsinghua University. High-power test had been done on them to study the breakdown phenomenon in high gradient and how the choke affects high-gradient properties. A max gradient of 75 MV/m were achieved by the choke-mode structure and the choke breakdown limited further increasing of the gradient. Inner surface inspection of the choke-mode structures indicates that the axial part of the choke limits the performance of the structure. Based on this observation, three new choke-mode structures were designed and being manufactured.

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TUPAB011

Beam Dynamics Simulation in Two Versions of New Photogun for FCC-ee Electron Injector Linac

injection, simulation, electron, beam-loading

1326

S.M. Polozov, T.V. Bondarenko
MEPhI, Moscow, Russia

New high-energy frontier project FCC is now under development at CERN. The project includes three modes: ee, hh and eh interactions for FCC. New injection system for FCC-ee is planned to consist of new ~ 2-14 GeV electron linac and electron-positron converter. Injector linac should provide two regimes: ~250 pC bunches for injection and ~6 nC bunches for e⁻/e⁺ conversion. Two possible schemes of photogun are comprised and results of beam dynamics simulation in both FCC-ee injection linac photoguns are discussed.

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TUPAB012

Comparison of Prismatic and Circular Biperiodical Accelerating Structures of 27 GHz Operating Frequency

coupling, simulation, impedance, alignment

1330

Yu.D. Kliuchevskaia, S.M. Polozov
MEPhI, Moscow, Russia

As known a biperiodical accelerating structure (BAS) represents as a system based on disk loaded waveguide (DLW) operating on Pi/2 mode and is widely used for the compact electron linacs. Earlier such structure with operating frequency of 27 GHz was proposed for medical application and beam dynamics simulations and electrodynamics modeling were done [1-2]. It was shown that such structure manufacturing should have very high accuracy and can be manufactured using electro erosive technology only. It is very complex for axi-symmetrical geometry to use such technology. Interesting option will to use a prismatic geometry BAS. In this report the design of a prismatic and disk-loaded BAS will discus, simulation results and analysis will presented.

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TUPAB013

Beam Dynamics Study and Electrodynamics Simulations for the CW RFQ

rfq, cavity, simulation, Windows

1333

S.M. Polozov, W.A. Barth, T. Kulevoy, Y. Lozeev, S. Yaramyshev
MEPhI, Moscow, Russia
W.A. Barth, S. Yaramyshev
GSI, Darmstadt, Germany
W.A. Barth
HIM, Mainz, Germany
T. Kulevoy, S.M. Polozov
ITEP, Moscow, Russia

A compact university scale CW research proton accelerator, as well as driver linac with three branches of experimental beam lines, delivering beam energy of 3, 30 and 100 MeV for experiments, are recently under development in Russia. First results of the beam dynamics simulations for such a linac were already shown in *. The recently developed advanced RFQ cavity design is presented. The low energy beam transport line (LEBT), dedicated to transport proton beam from an ECR ion source, as well as to match beam emittance to the RFQ acceptance, was investigated. The results of beam dynamics simulations for LEBT are discussed.
* W.Barth, T.Kulevoy, S.Polozov, S.Yaramyshev, Proc. of HB-2016, 188-190.

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TUPAB014

Preliminary Design of FCC-ee Pre-Injector Complex

emittance, damping, positron, booster

1337

S. Ogur, Y. Papaphilippou, F. Zimmermann
CERN, Geneva, Switzerland
A.M. Barnyakov, A.E. Levichev, D.A. Nikiforov
BINP SB RAS, Novosibirsk, Russia
K. Furukawa, N. Iida, F. Miyahara, K. Oide
KEK, Ibaraki, Japan

The design of a 100 km circular e⁺e⁻ collider with extremely high luminosity is an important component of the global Future Circular Collider (FCC) study hosted by CERN. FCC-ee is being designed to serve as Z, W, H and top factory, covering beam energies from 45.6 to 175 GeV. For the injectors, the Z-operation is the most challenging mode, due to the high total charge and low equilibrium emittance in the collider at this energy. Thus, fulfilling the Z-mode will also meet the demands for all other modes of FCC-ee. This goal can be achieved by using a 6 GeV NC linac with an S-band RF frequency of 2.856 GHz and a repetition rate of 100 Hz. This linac will accelerate two bunches per RF pulse, each with a charge of 6.5 nC. Positrons will be generated by sending 4.46 GeV e^- onto a hybrid target so that the e⁺ created can still be accelerated to 1.54 GeV in the remaining part of the same linac. The emittance of the e⁺ beam will then shrink to the nm level in a 1.54 GeV damping ring. After damping, the e⁺ will be reinjected into the linac and accelerated to 6 GeV. The e^- and e⁺ will then be accelerated alternately to 45.6 GeV in the booster, before they are injected into the collider.

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TUPAB016

The CLIC Main Linac Module Updated Design

alignment, klystron, operation, luminosity

1345

C. Rossi, M. Aicheler, N. Catalán Lasheras, R. Corsini, S. Döbert, A. Grudiev, A. Latina, H. Mainaud Durand, M. Modena, H. Schmickler, D. Schulte, S. Stapnes, I. Syratchev, A.L. Vamvakas, W. Wuensch
CERN, Geneva, Switzerland
M. Aicheler
HIP, University of Helsinki, Finland

In 2016, CLIC implementation working groups have started their reflection on how to finalize the CLIC design work in the different areas of the project, aiming for a technical design and an overall implementation plan for CLIC being available for the next European Strategy Update around 2019. One of the working groups has focused its attention on the Main Linac hardware, which has brought together the different competences of the study with the aim of producing an advanced set of specifications for the design, installation and operation of the CLIC module. As the fundamental unit for the construction of the Main Beam linac, the CLIC module needs to move from the existing prototypes exploring its performance into an advanced and functional unit where the full life cycle of the module is considered. The progress of the working group activity is summarized in this paper, with considerations on the requirements for the design of the next-phase CLIC module.

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TUPAB017

Results of the Beam-Loading Breakdown Rate Experiment at the CLIC Test Facility CTF3

beam-loading, experiment, operation, klystron

1348

E. Senes, T. Argyropoulos, N. Catalán Lasheras, R. Corsini, D. Gamba, J. Giner Navarro, A. Grudiev, G. McMonagle, R. Rajamaki, X.F.D. Stragier, I. Syratchev, F. Tecker, W. Wuensch
CERN, Geneva, Switzerland
J. Giner Navarro
IFIC, Valencia, Spain
R. Rajamaki
Aalto University, School of Science and Technology, Aalto, Finland
E. Senes
Torino University, Torino, Italy

The RF breakdown rate is crucial for the luminosity performance of the CLIC linear collider. The required breakdown rate at the design gradient of 100 MV/m has been demonstrated, without beam presence, in a number of 12 GHz CLIC prototype structures. Nevertheless, the beam-loading at CLIC significantly changes the field profile inside the structures, and the behaviour with beam needs to be understood. A dedicated experiment in the CLIC Test Facility CTF3 to determine the effect of beam on the breakdown rate has been collecting breakdown data throughout the year 2016. The complete results of the experiment and the effect of the beam-loading on the breakdown rate are presented.

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TUPAB022

TRIUMF ARIEL e-Linac Ready for 30 MeV

cavity, cryomodule, TRIUMF, electron

1361

S.R. Koscielniak, Z.T. Ang, K. Fong, J.J. Keir, O.K. Kester, M.P. Laverty, R.E. Laxdal, Y. Ma, A.K. Mitra, T. Planche, D.W. Storey, E. Thoeng, B.S. Waraich, Z.Y. Yao, V. Zvyagintsev
TRIUMF, Vancouver, Canada

Funding: TRIUMF is funded under a contribution agreement with the National Research Council of Canada.
The ARIEL electron linac (e-linac) in its present configuration has a 10 mA electron gun and a single-cavity 10 MeV injector cryomodule followed by the accelerator cryomodule intended to house two 10-MeV-capable SRF cavities. There are momentum analysis stations at 10 MeV and 30 MeV. In October 2014, using a total of two cavities, the e-linac demonstrated 22.9 MeV acceleration. In 2017 an additional SRF cavity was installed in the accelerator cryomodule, thereby completing its design specification; and leading to 30 MeV acceleration capability. The 9-cell 1.3 GHz cavities are a variant of the TESLA type, modified for c.w. operation and recirculation. An unusual feature of the module is the power feed of two cavities by one klystron through a wave-guide type power divider, and closed loop control of the combined voltage from the cavities. Initial operation of the two-cavity control, including power and phase balancing, is reported.

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TUPAB023

Commissioning of the 10MeV Electron Injector Cryomodule for VECC at TRIUMF

cavity, cryomodule, TRIUMF, electron

1365

R.E. Laxdal, Y. Ma, R.R. Nagimov, D.W. Storey, E. Thoeng, Z.Y. Yao, V. Zvyagintsev
TRIUMF, Vancouver, Canada
U. Bhunia, A. Chakrabarti, S. Dechoudhury, V. Naik
VECC, Kolkata, India

TRIUMF (Vancouver) and VECC (Kolkata) have been engaged in a collaboration on superconducting electron linacs since 2008. The motivation for the collaboration was to support initiatives at both labs, ARIEL at TRIUMF and ANURIB at VECC, to augment the respective radioactive ion beam (RIB) programs with the addition of a high intensity electron linac driver to produce RIBs through photo-fission. The common linac architecture is based on five 1.3GHz nine-cell SRF cavities housed in three cryomodules; a single cavity injector (ICM) and a pair of two cavity accelerating modules (ACM). Final design goals are 50MeV and 10mA/3mA at TRIUMF/VECC respectively. A ARIEL e-linac demonstrator with two cold cavities in two modules successfully accelerated beam to 20MeV. Recently the VECC 10MeV injector cryomodule was commissioned with beam. A summary of the ICM design and results of the commissioning will be presented.

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TUPAB028

Measuring the Spectral Response of Cs-K-Sb Photocathodes for BERLinPro

SRF, cathode, electron, emittance

1378

H. Kirschner, A. Jankowiak, T. Kamps, J. Kühn, M.A.H. Schmeißer
HZB, Berlin, Germany

A spectral response setup was commissioned at the Cs-K-Sb photocathode preparation and analysis system developed for the BERLinPro project. The setup is designed to measure the spectral quantum efficiency from 370 to 700 nm and to monitor the photocurrent during the photocathode growth process and the photocathode lifetime at 515 nm.

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TUPAB040

Status Update of the SINBAD-ARES Linac Under Construction at DESY

electron, diagnostics, laser, acceleration

1412

B. Marchetti, R.W. Aßmann, S. Baark, U. Dorda, C. Engling, K. Flöttmann, I. Hartl, J. Hauser, J. Herrmann, M. Hüning, M. Körfer, B. Krause, G. Kube, J. Kuhlmann, S. Lederer, F. Ludwig, D. Marx, F. Mayet, M. Pelzer, I. Peperkorn, A. Petrov, S. Pfeiffer, S. Pumpe, J. Rothenburg, H. Schlarb, M. Titberidze, S. Vilcins, M. Werner, Ch. Wiebers, L. Winkelmann, K. Wittenburg, J. Zhu
DESY, Hamburg, Germany

ARES (Accelerator Research Experiment at Sinbad) is a linear accelerator for the production of low charge (from few pC to sub-pC) electron bunches with 100 MeV energy, fs and sub-fs duration and excellent arrival time stability. This experiment is currently under construction at DESY Hamburg and it is foreseen to start operation by the beginning of 2018 with the commissioning of the RF-gun. After an initial beam characterization phase, ARES will provide high temporal resolution probes for testing novel acceleration techniques, such as Laser driven plasma Wake-Field Acceleration (LWFA), Dielectric Laser Acceleration (DLA) and THz driven acceleration. In this work we present an overview of the present design of the linac with a special focus on 3D integration and planned installation phases of the beamline.

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TUPAB042

Current Status of IPM Linac Control System

controls, EPICS, PLC, electron

1418

S. Haghtalab, F. Abbasi
Shahid Beheshti University, Tehran, Iran
S. Ahmadiannamin
ILSF, Tehran, Iran
F. Ghasemi, M. Lamehi
IPM, Tehran, Iran

This paper reports the progress of the control system for IPM 10 MeV accelerator. As an electron linac, it consists of beam injection acceleration tube, radio frequency production and transmission, target, diagnostics and control and safety. In support of this source, an EPICS-based integrated control system has been designed and being implemented from scratch to provide access to the critical control points and continues to grow to simplify operation of the system. In addition to a PLC-based machine protection component and IO interface, a CSS-based suite of control GUI monitors systems including Modulator and RF, Vacuum, Magnets, and electron gun. An overview of this system is presented in this article.

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TUPAB044

SIMULATION, MEASUREMENT AND TUNING OF A PROTOTYPE DISK LOADED RF CAVITY

electron, simulation, cavity, operation

1424

S. Ahmadiannamin
ILSF, Tehran, Iran
F. Abbasi, F. Ghasemi
Shahid Beheshti University, Tehran, Iran
M. Lamehi, M. Shirshekan
IPM, Tehran, Iran

Constant impedance accelerator RF cavities are constructed from similar resonator cells that stacked to each other. Best operation condition is achieved when all of cells resonate in one resonance frequency with similar quality factors. So, measurement and tuning of RF cavities is the critical step for final best operation of linear accelerators. In this paper, the electromagnetic computer simulations, RF measurement and final tuning of a nine cell periodic accelerator structure was represented. All of cavities tuned in one resonant frequency and according to theoretical concepts we obtain nine resonant modes from RF measurements by vector network analyzer.

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TUPAB045

Design and Construction of a Pre-Buncher for Iranian Low Energy Linear Accelerator

cavity, electron, simulation, coupling

1428

S. Ahmadiannamin
ILSF, Tehran, Iran
M. Bahrami, M.R. Khalvati, M. Lamehi, H. Shaker, M. Shirshekan
IPM, Tehran, Iran

Iranian IPM low energy linear accelerator project (e-Linac) is in its final steps for commissioning. Beam dynamic simulations with and without Pre-buncher prior to buncher was done. The results represent improvement in capturing efficiency better than 25% by application of Pre-buncher cavity. In this paper, we present the simulation, construction, RF measurements and vacuum test results. After construction, we measured RF reflection coefficient better than -33 dB in the nominal frequency of 2997.9 MHz with quality factor of 4500.

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TUPAB048

Long Beam Pulses With SLED Compression in DAΦNE LINAC

gun, electron, klystron, flattop

1434

P. Valente
INFN-Roma, Roma, Italy
M. Belli, B. Buonomo, R. Ceccarelli, A. Cecchinelli, R. Clementi, D.G.C. Di Giulio, L.G. Foggetta, G. Piermarini, L.A. Rossi, S. Strabioli, R. Zarlenga
INFN/LNF, Frascati (Roma), Italy

The DAΦNE LINAC is a ~60 m long, S-band (2856 MHz) linear accelerator, made up by four 45 MW klystrons with SLED compression, and by 15 travelling-wave, 2/3p, SLAC-type, 3 m long accelerating sections. It serves as injector of the DAΦNE e⁺ e⁻ collider, with 510 MeV, 10 ns long, electron and positron pulses, and the Beam-Test Facility extraction line, with variable beam energy and intensity and with pulses from 1.5 to 40 ns. A new pulsing system for the gun allows longer beam pulses, but the shape of the accelerating field in the sections due to the SLED compression has to be taken into account. We describe the tuning of the RF power, phase and delays in the pre-buncher, buncher and following accelerating sections, and the results of the tests performed in order to reach >200 ns 500 MeV electron pulses and the characterization of the quality of the beam in terms of energy spread, time distribution, etc.

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TUPAB049

Development of the High Power Terahertz Light Sources at LEBRA Linac in Nihon University

target, electron, radiation, FEL

1437

T. Sakai, K. Hayakawa, Y. Hayakawa, K. Nogami, T. Tanaka
LEBRA, Funabashi, Japan
H. Ogawa, N. Sei
AIST, Tsukuba, Ibaraki, Japan

Funding: This work was supported by JSPS KAKENHI (Grant-in-Aid for Young Scientists (B)) Grant Number JP16K17539.
Development of a THz light source has been underway at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University in collaboration with National Institute of Advanced Industrial Science and Technology (AIST) since 2011. Basic research on coherent transition radiation (CTR) in the THz region has been carried out using the Parametric X-ray Radiation (PXR)-beam line of LEBRA. Since fiscal year 2016, the THz transport line has been constructed on the same axis as the PXR beam line taking the construction cost and simultaneous use of the two beams into account. Basic measurement and intensity upgrading test have been carried out for the THz lights generated on the PXR-generating electron beam line. The average intensity of the THz lights obtained at the output port in the accelerator room has been 5 mW. Construction of the THz transport beam line and the property of the THz lights is discussed in the report.

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TUPAB070

S-Band Accelerating Structure for High-Gradient Upgrade of TTX

electron, impedance, simulation, accelerating-gradient

1485

D.Z. Cao, H.B. Chen, Y.-C. Du, W. Gai, W.-H. Huang, X.C. Meng, J. Shi, C.-X. Tang, X.W. Wu, H. Zha
TUB, Beijing, People's Republic of China

Thomson scattering x-ray source is an indispensable scientific X-ray imaging tool in various research fields. The 3-meter S-band linac in Tsinghua Thomson scatter-ing X-ray source (TTX) has been running at an accelerat-ing gradient of 15 MV/m so far. The gradient will be upgraded to 30MV/m by replacing the old structure with a shorter linac. Detailed optimization of the RF design of the new S-band linac structure is presented in this paper. Finally, further research on energy upgrade with X-band structures are also discussed.

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TUPAB083

Commissioning Experience and Beam Optimization for DCLS Linac

gun, emittance, FEL, cathode

1509

M. Zhang, D. Gu, Q. Gu, D. Huang, Z. Wang
SINAP, Shanghai, People's Republic of China

Dalian Coherent Light Source (DCLS), which will focus on the Physical Chemistry with time-resolved pump-probe experiments and EUV absorption spectroscopy techniques, is the first high gain FEL user facility in China. The 300MeV linac consists of a laser-driven rf-gun followed by 7 Sband accelerating tubes. A magnetic chicane is adopted to get the desired 300A peak current. After 5 months component installation, first photoelectrons were generated on 17 August 2016. In this paper, we give a summary of the commissioning experience and the beam parameters measurements. In addition, beam jitter sources are studied based on real machine performances.

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TUPAB084

Beam Stability Modeling and Jitter Control for SXFEL Linac

FEL, controls, quadrupole, klystron

1513

M. Zhang, R.B. Deng, D. Gu, Q. Gu, D. Huang, Z. Wang
SINAP, Shanghai, People's Republic of China

FEL operations foresee stringent requirements for the stability of the global linac output parameters and this requirement is particularly stringent for the successful operation of an externally seeded FEL. In order to understand the sensitivity of these parameters to jitters of various error sources along the SXFEL linac, studies have been performed based on analytical methods and tracking code simulations. Using the tolerance budget as guidance, beam jitter control techniques are discussed on the view of the beam dynamics.

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TUPAB092

MYRRHA Control System Development

controls, proton, framework, target

1527

D. Vandeplassche
SCK•CEN, Mol, Belgium
J. Belmans, W. De Cock
Studiecentrum voor Kernenergie - Centre d'Étude de l'énergie Nucléaire (SCK•CEN), Mol, Belgium
R. Modic, K. Strniša, K. Žagar
Cosylab, Ljubljana, Slovenia

The approach to the MYRRHA Control System (CS) development will be described. The effort, time and resources needed to develop the control systems are often underestimated by a significant factor. This brings unnecessary setbacks to the projects. Understanding CS requirements at an early machine conception stage is paramount for adequate CS design. Awareness of sheer project size and interdisciplinary complexity is imperative for successful project execution. In the first part of the paper the MYRRHA roadmap, milestones, status and its future needs will be presented with an emphasis on the phased approach leading to the 100 MeV program. The second part of the paper will give the status of the MYRRHA CS development within this phased approach. Best practices for coherent integration will be discussed. The CS should provide a flexible framework for the integration of devices. Interfaces and services need to be defined early in the integration process, and the number of different interfaces and platforms should be kept to a minimum. The implications of the choice of technologies and of SW development processes on the overall reliability and availability have to be established.

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TUPAB093

Race-Track Microtron with Pulse-to-Pulse Beam Energy Switch

electron, microtron, extraction, focusing

1530

Yu.A. Kubyshin
UPC, Barcelona, Spain
V.I. Shvedunov, I.Yu. Vladimirov
LEA MSU, Moscow, Russia
V.I. Shvedunov
SINP MSU, Moscow, Russia

A race-track microtron with a few beam orbits can be an alternative to a standard electron linear accelerator in a number of applications in which high beam power is not needed, like radiation therapy, industrial radiography or cargo inspection. In these cases the advantages of race-track microtrons are low RF power consumption, and consequently low cost of the RF system, and a possibility of beam energy switch in a wide range by extracting the beam from different orbits. In the present work we describe the concept of a race-track microtron with pulse-to-pulse beam energy switch in the range from 3 MeV to 9 MeV. Special attention is given to the optimization of the end magnets of a new type which provide both the accelerating structure bypass and vertical beam focusing.

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TUPAB094

Emittance Improvements in the MAX IV Photocathode Injector

emittance, gun, quadrupole, laser

1533

J. Andersson, F. Curbis, M. Kotur, F. Lindau, S. Thorin, S. Werin
MAX IV Laboratory, Lund University, Lund, Sweden

The MAX IV injector design predicts a beam with 100 pC of charge and an emittance lower than 1 mm mrad. The photocathode pre-injector is based on the now close to standard 1.6-cell gun adapted to 2.9985 GHz, in combination with a Ti:Sapphire laser system. This system reaches the requirements of the injector operation for the SPF, but can be tuned beyond specifications to open up new operation modes. During 2016 and 2017 several aspects where investigated to improve the emittance from the current gun, the goal was to meet the SPF specifications. In this paper we report on the progress, discuss the steps taken leading to a final emittance of ~ 1 mm mrad and beyond.

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TUPAB097

MAXIV Photocathode Gun Laser System Specification and Diagnostics

laser, gun, diagnostics, cathode

1544

F. Lindau, J. Andersson, J. Björklund Svensson, M. Brandin, F. Curbis, L. Isaksson, M. Kotur, D. Kumbaro, E. Mansten, D. Olsson, R. Svärd, S. Thorin, S. Werin
MAX IV Laboratory, Lund University, Lund, Sweden
J. Björklund Svensson
Lund University, Division of Atomic Physics, Lund, Sweden

The MAXIV injector has two guns - a thermionic used for ring injections, and a photocathode used for short pulse facility operation. A commercial Ti:sapphire laser from KMLabs drives the copper based photocathode gun. It has been running without major issues for more than 3 years. The laser delivers up to §I{500}{\textmu J} on the cathode at the third harmonic, §I{263}{nm}, via a vacuum laser transport system. To achieve the desired pulse duration of 2–§I10{ps} the laser pulses, originally ~§I{100}{fs} long, are stretched with a prism pair and the resulting §I{1.5}{ps} pulses stacked by a series of birefringent \textalpha -BBO crystals. Diagnostics consist of photodiodes, spectrometers, and cameras. Longitudinal pulse characterization is done with a cross correlator and a UV FROG.

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TUPAB099

Status of MAX IV Linac Beam Commissioning and Performance

gun, storage-ring, injection, sextupole

1547

S. Thorin, J. Andersson, M. Brandin, F. Curbis, L. Isaksson, M. Kotur, D. Kumbaro, F. Lindau, E. Mansten, D. Olsson, R. Svärd, S. Werin
MAX IV Laboratory, Lund University, Lund, Sweden
J. Björklund Svensson
Lund University, Division of Atomic Physics, Lund, Sweden

The MAX IV linac is used both for full energy injection into two storage rings at 3 GeV and 1.5 GeV, and as a high brightness driver for a Short Pulse Facility (SPF). The linac has also been designed to handle the high demands of an FEL injector. The linac is now routinely injecting into the two storage rings, and commissioning work is focused towards delivering high brightness pulses to the SPF. In this paper we present results from characterisation of the linac in ring injection mode, as well as results from measurements of key parameters for the SPF such as bunch length and emittance.

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TUPAB123

Hard X-Ray and Soft X-Ray Undulator Segments for the Linear Coherent Light Source Upgrade (LCLS-II) Project

undulator, photon, FEL, electron

1605

M. Leitner, D. Arbelaez, A.J. Band, D. Bianculli, A.P. Brown, J.N. Corlett, A.J. DeMello, J.R. Dougherty, L. Garcia Fajardo, K. Hanzel, M. Hoyt, D.E. Humphries, D. Jacobs, C. Joiner, J.-Y. Jung, D. Leitner, S. Marks, K.A. McCombs, D.V. Munson, K.L. Ray, D.A. Sadlier, J.J. Savino, D. Schlueter, E.J. Wallén, V. Waring, A. Zikmund
LBNL, Berkeley, California, USA
C.J. Andrews, D.E. Bruch, A.L. Callen, G. Janša, S. Jansson, K.R. Lauer, Yu.I. Levashov, D.S. Martinez-Galarce, B.D. McKee, H.-D. Nuhn, Â. Oven, M. Rowen, Z.R. Wolf
SLAC, Menlo Park, California, USA

Funding: Work supported by the Director Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Stanford Linear Accelerator Laboratory is currently constructing the Linear Coherent Light Source II (LCLS-II), a free-electron laser (FEL) which will deliver x-rays at an energy range between 0.2 keV and 5 keV at high repetition rate of up to ~1 MHz using a new 4 GeV superconducting RF linac, and at and an energy range between 1 keV and 25 keV when driven by an existing copper linac at up to 120 Hz repetition rate. To cover the full photon energy range, LCLS-II includes two variable-gap, hybrid-permanent-magnet undulator lines: A soft x-ray undulator (SXR) line with 21 undulator segments optimized for a photon energy range from 0.2 keV to 1.3 keV plus a hard x-ray undulator (HXR) line with 32 undulator segments designed for a photon energy range from 1.0 keV to 25.0 keV. Lawrence Berkeley National Laboratory is responsible for fabricating the 53 undulator segments. This paper summarizes the main parameters and design attributes for both LCLS-II undulator segment types.

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TUPAB125

Magnetic Field Measurements at LBNL on Soft X-Ray and Hard X-Ray Undulator Segments for the Linear Coherent Light Source Upgrade (LCLS-II) Project

undulator, photon, software, alignment

1612

E.J. Wallén, D. Arbelaez, J.N. Corlett, L. Fajrado, H.W. Kim, M. Leitner, S. Marks, D. Schlueter, A. Zikmund
LBNL, Berkeley, California, USA
Yu.I. Levashov, H.-D. Nuhn, Z.R. Wolf
SLAC, Menlo Park, California, USA

Funding: Work supported by the Director, O'ce of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Stanford Linear Accelerator Laboratory is currently constructing the Linear Coherent Light Source II (LCLS-II), a FEL which will deliver x-rays at an energy range 0.2-5 keV at high repetition rate of up to 1 MHz using a new 4 GeV superconducting linac, and at an energy range 1-25 keV when using the existing copper linac at up to 120 Hz. To cover the full photon energy range, LCLS-II includes two variable-gap, hybrid-type permanent magnet undulator lines: A soft x-ray undulator (SXR) line with 21 undulator segments for the photon energy range 0.2-1.3 keV plus a hard x-ray undulator (HXR) line with 32 undulator segments designed for a photon energy range from 1-5 keV when using the superconducting linac. The HXR line is also designed to support 25 keV and higher photon energies when using the existing copper linac. Lawrence Berkeley National Laboratory (LBNL) is responsible for fabricating the undulators and tuning 23 of the HXR undulators. This paper summarizes the magnetic field measurements carried out on the pre-production undulators and describes the plans at LBNL for the magnetic measurements on the HXR undulators in series production.

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TUPAB130

Status of the LCLS-II Superconducting RF Linac

cryomodule, cavity, operation, FEL

1630

A. Burrill
SLAC, Menlo Park, California, USA

The LCLS-II project requires the assembly and installation of 37 cryomodules in order to deliver a 4 GeV electron beam to the undulators to produce both soft and hard x-ray pulses at a repetition rate up to 1 MHz. All of the cryomodules will operate in continuous wave mode, with 35 operating at 1.3 GHz for acceleration and 2 operating at 3.9 GHz to linearize the longitudinal beam profile. The assembly and testing of the 1.3 GHz cryomodules is well underway and the 3.9 GHz cryomodule work is entering into the pre-cryomodule testing and component validation phase. Both of these efforts will be reported on in this paper.

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TUPIK031

Driver-Witness-Bunches for Plasma-Wakefield Acceleration at the MAX IV Linear Accelerator

plasma, electron, wakefield, simulation

1743

J. Björklund Svensson, H.E. Ekerfelt, O. Lundh
Lund University, Lund, Sweden
J. Andersson, F. Curbis, M. Kotur, F. Lindau, E. Mansten, S. Thorin, S. Werin
MAX IV Laboratory, Lund University, Lund, Sweden

Beam-driven plasma-wakefield acceleration is an acceleration scheme promising accelerating fields of at least two to three orders of magnitude higher than in conventional radiofrequency accelerating structures. The scheme relies on using a charged particle bunch (driver) to drive a non-linear plasma wake, into which a second bunch (witness) can be injected at an appropriate distance behind the first, yielding a substantial energy gain of the witness bunch particles. This puts very special demands on the machine providing the particle beam. In this article, we use simulations to show that, if driver-witness-bunches can be generated in the photo-cathode electron gun, the MAX IV Linear Accelerator could be used for plasma-wakefield acceleration.

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TUPIK055

Target Investigation Driven by a 10 MeV Electron Linac for Bremsstrahlung Production

target, electron, radiation, photon

1819

M. Yarmohammadi Satri, M. Lamehi, H. Shaker
IPM, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran

IPM E-Linac is a 10 MeV electron linear accelerator presently under construction at Institute for Research in Fundamental Sciences (IPM). It will accelerate electron from 45 keV to 10 MeV along the 160 cm accelerating tube. One of the beam energy measurement devices is designed based on the production of bremsstrahlung radiation. Target of the electron linac presents a key role in the production of bremsstrahlung. In this paper, we present the simulation results for an investigation on the bremsstrahlung radiation production based on target thickness, radius and atomic number, Z. We have applied Fluka Monte Carlo code for collecting the dose equiva-lent of generated bremsstrahlung along the target central axis at 30cm located downstream the target.

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TUPIK076

Pre-Alignment Techniques Developments and Measurement Results of the Electromagnetic Center of Warm High-Gradient Accelerating Structures

simulation, alignment, wakefield, target

1868

N. Galindo Munoz, N. Catalán Lasheras
CERN, Geneva, Switzerland
V.E. Boria
DCOM-iTEAM-UPV, Valencia, Spain
A. Faus-Golfe
IFIC, Valencia, Spain

Funding: PACMAN is founded under the European Union's 7th Framework Program Marie Curie Actions, grant PITN-GA-2013-606839
In the framework of the PACMAN project we have developed a test set-up to measure the electromagnetic centre of high gradient accelerating structures for alignment purposes. We have demonstrated with previous simulation studies that a resolution of 1 m is possible. The improvements applied on the technique and on the set-up, calibrations and the equipment instrumentation allows the measurement of the electromagnetic centre, with a final precision of 1.09 m in the horizontal plane and 0.58 m in the vertical plane. The experimental measurements and the simulation studies as a support to justify the numbers obtained are presented and discussed.

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TUPIK079

Development and Status of Protection Functions for the Normal Conducting LINAC at ESS

vacuum, proton, timing, monitoring

1880

R. Andersson, E. Bargalló, S. Kövecses, A. Nordt, M. Zaera-Sanz
ESS, Lund, Sweden
C. Hilbes, M. Rejzek
ZHAW, Winterthur, Switzerland

The European Spallation Source faces a great challenge in succeeding with its ambitious availability goals. The aim is to construct a machine that allows for 95% availability for neutron beam production. This goal requires a robust protection system that allows for high availability by continuously monitoring and acting on the machine states, in order to avoid long facility downtimes and optimize the operation at any stage. The normal conducting section consists of the first 48 meters of the machine, and performs the initial acceleration, bunching, steering, and focusing of the beam, which sets it up for optimal transition into the superconducting section. Through a fit-for-purpose risk management process, a set of protection functions has been identified. The risk identification, analysis, and treatment were done in compliance with modern safety and ISO standards. This ensures that the risks, in this case downtime and equipment damage, are properly prevented and mitigated. This paper describes this process of defining the protection functions for the normal conducting linac at ESS.

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TUPIK080

Accelerator Personnel Safety Systems for European Spallation Source

radiation, PLC, proton, controls

1884

M. Mansouri, S.L. Birch, A. Nordt, D. Paulic, Y.K. Sin, A. Toral Diez
ESS, Lund, Sweden

The European Spallation Source (ESS) is a collabora-tion of 17 European countries to build the world's most powerful neutron source for research. ESS is under con-struction since 2014 and it will produce first neutrons in 2019. The linear proton accelerator is composed of nor-mal conducting sections plus the superconducting linac. When operational, such facilities include various hazards, such as ionizing radiation, high voltage and oxygen defi-ciency. The accelerator Personal Safety System (PSS) limits exposure to them and ensures personnel safety in the accelerator tunnel. It will be developed in accordance with IEC 61508 standard (Functional Safety of Electri-cal/Electronic/Programmable Electronic Safety-related Systems), which has become a good practice in similar facilities to develop safety related systems. This paper gives an overview of the accelerator PSS and its subsys-tems. The progress of the accelerator PSS design and the selected software and hardware technologies will also be described.

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TUPIK098

Micrometric Propagation of Error Using Overlapping Streched Wires for the CLIC Pre-Alignment

simulation, network, alignment, collider

1935

H. Mainaud Durand
CERN, Geneva, Switzerland
J. Pfingstner
University of Oslo, Oslo, Norway
V. Rude
ESGT-CNAM, Le Mans, France

The geodetic network for the Compact LInear collider (CLIC) will consist of a combination of overlapping wires stretched in parallel and Wire Positioning Sensors (WPS). Such a configuration will limit the propagation of errors (maximum deviation w.r.t. a fit line) below 10 micrometres over 200 metres. These first results were obtained through simulations in 2009, with hypotheses remaining to be validated. New experimental results have been obtained allowing to reconsider the precision and accuracy of WPS sensors and the knowledge of stretched wires. This paper presents the experimental results obtained on dedicated calibration benches and on a facility made of three overlapping stretched wires over a length of 140 metres including WPS sensors measurements. It confirms the possibility to have a propagation of error below 10 micrometres using overlapping stretched wires combined with WPS sensors.

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TUPIK100

Methodology Applied for Dependability Studies on the Compact Linear Collider

simulation, operation, quadrupole, collider

1943

O. Rey Orozko, A. Apollonio, M. Jonker
CERN, Geneva, Switzerland

The Compact Linear Collider (CLIC) scheme presents several challenges in terms of reliability and availability. The goal of the study is to demonstrate the requirements for availability and reliability by identifying the key factors on failure effects and analysing possible operational scenarios and designs. Hence, a good knowledge on CLIC system structures, failure modes and failure effects is needed. This paper reports about the set-up of the studies from the definition of the CLIC failure catalogue to the implementation of the models and analysis of the results. It will present in detail the steps that need to be followed when performing such a study. Finally, the CLIC Drive Beam Quadrupoles powering system will be presented as a use-case.

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TUPIK103

Development of Automatic Turn-on Systems for TPS Machine

operation, injection, controls, booster

1954

T.Y. Lee, B.Y. Chen, C.H. Chen, J.Y. Chen, M.-S. Chiu, S. Fann, C.S. Huang, C.C. Liang, W.Y. Lin, Y.-C. Liu, H.-J. Tsai, F.H. Tseng
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) has been successfully commissioned and has reached now stable operation. Now, the machine must be turned off routinely for week-ly maintenance. While following standard machine turn-on procedures for now, we have developed an automatic turn-on program to accelerate operation, for automatic system status checks and to prevent human errors. The turn-on program process flow includes: turn-on of the LTB (linac to booster transport line), the BTS (booster to storage ring transport line), the SR (storage ring), the BR (booster ring) power supplies and BR&SR pulsers as well as degaussing magnets, turning on the BR&SR RF sys-tems, activating the linac electron source, opening all insertion device (ID) gaps to their parking positions, set-ting all ID phases to zero, controlling all front ends (FEs) and loading the desired machine lattice. Individual pro-cedures can be executed alone depending on the desired practical situation. Experience so far shows, that it takes about 30 minutes to proceed from tunnel safety search to the injection ready state of the light source, including a 20 minute period for magnet degaussing.

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TUPIK104

Effects of Non-axisymmetric Solenoid Field on Beam Quality in Velocity Bunching

solenoid, electron, emittance, alignment

1958

Y.H. Wen
NTHU, Hsinchu, Taiwan
C.H. Chen, N.Y. Huang, W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan

Space-charge effect is not negligible during the early stage of beam acceleration in a photoinjector rf linac that is operated for generation of short electron pulses by velocity bunching. A solenoid with iron shield can be used to provide the required axis-symmetric magnetic field to balance the radial space-charge force of the beam. However, the iron shield cannot be perfectly symmetric because openings are reserved for feeding water pipes and electrical cables to the coils. In addition, alignment errors of the solenoid may also spoil the symmetry of the focusing field. In this study, simulation is carried out to investigate how does the non-axisymmetric solenoid field of different origins influence beam properties, such as beam size, transverse emittance during the rf bunch compression.

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TUPVA052

The SARAF-LINAC Project 2017 Status

cryomodule, diagnostics, status, controls

2194

N. Pichoff, N. Bazin, D. Chirpaz-Cerbat, R. Cubizolles, J. Dumas, R.D. Duperrier, G. Ferrand, B. Gastineau, P. Gastinel, F. Gougnaud, M. Jacquemet, C. Madec, L. Napoly, P.A.P. Nghiem, F. Senée, D. Uriot
CEA/IRFU, Gif-sur-Yvette, France
D. Berkovits
Soreq NRC, Yavne, Israel
M. Di Giacomo
GANIL, Caen, France

SNRC and CEA collaborate to the upgrade of the SARAF accelerator to 5 mA CW 40 MeV deuteron and proton beams (Phase 2). CEA is in charge of the design, construction and commissioning of the superconducting linac (SARAF-LINAC Project). This paper presents to the accelerator community the status at March 2017 of the SARAF-LINAC Project.

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TUPVA055

Further Investigations for a Superconducting cw-LINAC at GSI

cavity, ion, heavy-ion, solenoid

2197

W.A. Barth, M. Heilmann, S. Yaramyshev
GSI, Darmstadt, Germany
K. Aulenbacher
IKP, Mainz, Germany
K. Aulenbacher, F.D. Dziuba, V. Gettmann, M. Miski-Oglu
HIM, Mainz, Germany
M. Basten, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany
S. Yaramyshev
MEPhI, Moscow, Russia

For superconducting (sc) accelerator sections operating at low and medium beam energies very compact accelerating-focusing structures are strongly required, as well as short focusing periods, high accelerating gradients and very short drift spaces. The Facility for Antiproton and Ion Research (FAIR) is going to use heavy ion beams with extremely high peak current from UNiversal Linear ACcelerator (UNILAC) and the synchrotron SIS18 as an injector for the SIS100. To keep the GSI-Super Heavy Element program competitive on a high level and even beyond, a standalone sc continuous wave LINAC in combination with the upgraded GSI High Charge State injector is envisaged. In preparation for this, testing of the first LINAC section (financed by HIM and GSI) as a demonstration of the capability of 216 MHz multi gap Crossbar H-structures (CH) is still ongoing, while an accelerating gradient of 9.6 MV/m (4K) at a sufficient quality factor has been already reached in a horizontal cryostat. As a final R&D step towards an entire LINAC three advanced cryo modules, each comprising two short CH cavities, should be built until 2019, serving for first user experiments at the coulomb barrier.

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TUPVA058

Status of the FAIR pLinac

proton, rfq, diagnostics, cavity

2208

C.M. Kleffner, R. Berezov, D. Daehn, J. Fils, P. Forck, L. Groening, M. Kaiser, K. Knie, C. Mühle, S. Puetz, A. Schnase, G. Schreiber, T. Sieber, J. Trüller, W. Vinzenz, C. Will
GSI, Darmstadt, Germany
U. Ratzinger
IAP, Frankfurt am Main, Germany

This paper describes the development progress of the 70 MeV, 70 mA proton injector for the FAIR facility. The injector comprises an ECR-type high current proton source followed by a ladder 4-rod RFQ and six normal conduction CH-DTL accelerating cavities. This unique design allows for a compact structure. The design work of the cavities has been mostly completed by our collaberation partners at IAP Frankfurt. The design of the buncher cavities, the mechanical integration as well as beam diagnostic devices are currently under development. The construction of a new modulator for the pLinac rf-system has been started on site. The proton source and the LEBT as well as the subsequent chopper are currently assembled at CEA/Saclay. Beam commissioning of the source at Saclay will start at the beginning of 2017. An overview of the pLinac main parameters and design choices is given, and the overall status reported.

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TUPVA061

Beam Dynamics Study for the HIM&GSI Heavy Ion SC CW-LINAC

cavity, ion, acceleration, simulation

2217

S. Yaramyshev, W.A. Barth, M. Heilmann
GSI, Darmstadt, Germany
K. Aulenbacher
IKP, Mainz, Germany
K. Aulenbacher, W.A. Barth, V. Gettmann, M. Miski-Oglu
HIM, Mainz, Germany
W.A. Barth, S. Yaramyshev
MEPhI, Moscow, Russia
M. Basten, M. Busch, F.D. Dziuba, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany

A sc cw-linac with variable output energy from 3.7 to 7.5 MeV/u for ions with mass to charge ratio of A/Z<6 is recently under development at HIM and GSI. Following the results of the latest RF-tests with the newly constructed sc CH-DTL cavity, even heavier ions up to Uranium 28+ could be potentially accelerated with the already reached higher RF-voltage. Also the possibility for an up to 10 MeV/u increased output energy, using the same 13 independent cavities, is under consideration. All these options require an advanced beam dynamics layout, as well as a versatile procedure for transverse and longitudinal beam matching along the entire linac. The proposed algorithms are discussed and the obtained simulation results are presented.

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TUPVA062

Construction of the MYRRHA Injector

quadrupole, cavity, diagnostics, beam-diagnostic

2221

D. Mäder, H. Höltermann, H. Hähnel, D. Koser, K. Kümpel, U. Ratzinger, W. Schweizer
BEVATECH, Frankfurt, Germany
C. Angulo, J. Belmans, L. Medeiros Romão, D. Vandeplassche
Studiecentrum voor Kernenergie - Centre d'Étude de l'énergie Nucléaire (SCK•CEN), Mol, Belgium
M. Busch, H. Podlech
IAP, Frankfurt am Main, Germany

A collaboration of SCK•CEN, IAP and BEVATECH GmbH is currently constructing the room temperature CH section of the 16.6 MeV CW proton injector for the MYRRHA project. The elaboration of all the construction readiness files for the construction of the accelerating cavities of the first CH section (1.5 to 5.9 MeV) is ongoing. In parallel, the planning, development and fabrication of all further components of this accelerator section is in progress, while the full study for the remaining section is under preparation. This contribution is documenting the most recent status.

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TUPVA064

Updated Cavities Design for the FAIR p-Linac

cavity, proton, quadrupole, coupling

2227

A. Almomani, M. Busch, F.D. Dziuba, U. Ratzinger, R. Tiede
IAP, Frankfurt am Main, Germany
F.D. Dziuba, C.M. Kleffner
GSI, Darmstadt, Germany

The research program of antiproton beams for the FAIR facility requires a dedicated 68 MeV, 70 mA proton injector. This injector will consist of an RFQ followed by six room temperature Crossbar H-type CH-cavities operated at 325 MHz. The beam dynamics had been revised by IAP Frankfurt in collaboration with GSI-FAIR in Darmstadt to further optimize the design. This step was followed by cavity RF design. The detailed mechanical cavity design will begin in 2017, while the quadrupole lenses are under production already. In this paper, besides an overview the RF design of the coupled cavities with integrated focusing triplets will be a main focus.

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TUPVA067

The KONUS IH-DTL Proposal for the GSI UNILAC Poststripper Linac Replacement

emittance, quadrupole, DTL, ion

2230

H. Hähnel, U. Ratzinger, R. Tiede
IAP, Frankfurt am Main, Germany

Funding: BMBF 05P15RFRBA
The GSI UNILAC will serve as the main injector for the upcoming FAIR project. Since the existing Alvarez DTL is in operation for more than 40 years, it has to be replaced to ensure reliable operation in the future. To this purpose a compact and efficient linac design based on IH-type cavities and KONUS beam dynamics has been designed at IAP Frankfurt*. It consists of five 10⁸ MHz IH-type cavities that can be operated by the existing UNILAC RF amplifier structure. The transversal focusing scheme is based on magnetic quadrupole triplet lenses. The optimized design provides full transmission and low emittance growth for the design current of 15 emA U²⁸⁺ accelerating the beam from 1.4 MeV/u to 11.4 MeV/u. Extensive error studies were performed to define tolerances and verify the stability of the design with respect to misalignment and injection parameters. The design provides a compact and cost efficient alternative to a new Alvarez linac. With a total length of just 22.8 meters it will leave room for future energy upgrades in the UNILAC tunnel.
* H. Hähnel, U. Ratzinger, R. Tiede, Efficient Heavy Ion Acceleration with IH-Type Cavities for High Current Machines in the Energy Range up to 11.4 MeV/u, in Proc. LINAC2016, paper TUPLR070

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TUPVA071

The MYRRHA-RFQ - Status and First Measurements

rfq, proton, dipole, ECR

2243

H. Podlech, K. Kümpel, C. Lorey, N.F. Petry, A. Schempp, P.P. Schneider
IAP, Frankfurt am Main, Germany
A. Bechtold
NTG, Gelnhausen, Germany
C. Zhang
GSI, Darmstadt, Germany

Funding: H2020, European Commission, grant agreement number 662186 (MYRTE)
The MYRRHA project requires a proton linac with an energy of 600 MeV with a beam current of 4 mA in cw operation. As first RF structure a 176 MHz 4-Rod RFQ has been chosen because of tuning possibilities, maintenance, lower capital costs and technological risk compared to a 4-Vane-RFQ. The aim of beam dynamics design was to preserve excellent beam quality and to avoid the creation of halo particles especially in the longitudinal plane. Using the NFSP (New Four-Section Procedure) with a soft and symmetric pre-bunching with full 360° acceptance it was possible to reach the requirements. The simulated transmission of the 4 m long RFQ is close to 100%. The electrode voltage has been chosen to 44 kV which gives enough transverse focusing but limits the required RF losses to about 25 kW/m. The cooling has been optimized for reliable operation and a new method of dipole compensation has been applied. The RFQ has been built and tuned with respect to field flatness. The paper describes the status of the RFQ and first measurements.

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TUPVA072

Conceptual Injector Design for an Electron-Ion-Collider Front-End

ion, rfq, heavy-ion, cavity

2246

H. Podlech, M. Busch, M. Schwarz
IAP, Frankfurt am Main, Germany
R.C. York
NSCL, East Lansing, Michigan, USA
C. Zhang
GSI, Darmstadt, Germany

An electron-hadron collider (EIC) could be the next large-scale nuclear physics facility in the United States. A hadron linac with a final energy of 40 AMeV (heavy ions) and up to 130 MeV for protons with an upgrade path to higher energies is required as the first step of the hadron accelerator chain. From a cost point of view superconducting technology seems to be the better choice above an energy of about 5 AMeV compared to a room temperature (rt) solution. This paper describes the conceptual design of a rt front-end up to an energy of 5 AMeV appropriate as initial element of the EIC hadron linac. It consists of two separate injectors based on efficient H-mode cavities, one optimized for heavy ions (Pb³⁰⁺) and the other optimized for protons and deuterons. Beam dynamics and first RF simulations are presented.

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TUPVA074

Status of the modulated 3 MeV 325 MHz Ladder-RFQ

rfq, simulation, operation, dipole

2249

M. Schütt, M.A. Obermayer, U. Ratzinger, M. Syha
IAP, Frankfurt am Main, Germany

Funding: BMBF 05P12RFRB9
Based on the positive results of the unmodulated 325 MHz Ladder-RFQ from 2013 to 2016, we develop a modulated 3.3 m Ladder-RFQ. The unmodulated Ladder-RFQ features a very constant voltage along the axis. It could withstand more than 3 times the operating power of which is needed in operation at a pulse length of 200μseconds. That corresponds to a Kilpatrick factor of 3. The 325 MHz RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the p-linac at FAIR. This particularly high frequency for a 4-Rod-type RFQ creates difficulties, which are challenging in developing an adequate cavity. The results of the unmodulated prototype have shown, that the Ladder-RFQ is a suitable candidate for that frequency. Inspired by the successful rf power test, the nominal vane-vane voltage was increased from 80 kV to 96 kV. The basic design and tendering of the RFQ has been successfully completed in 2016. EM simulations of a modulated full structure, especially in terms of field-flatness and frequency tuning, will be shown. Furthermore, the mechanical design including a direct cooling of the structure for duty cycles up to about 5% will be discussed.

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TUPVA075

Beam Dynamics for a High Current 3 MeV, 325 MHz Ladder-RFQ

emittance, rfq, proton, quadrupole

2252

M. Syha, M.A. Obermayer, U. Ratzinger, M. Schütt
IAP, Frankfurt am Main, Germany

Funding: BMBF 05P12RFRB9
After the successful measurements with a 0.8 m prototype (see Fig. 1), a 3.3 m Ladder-RFQ is under construction at IAP, Goethe University Frankfurt. It is designed to accelerate protons from 95 keV to 3 MeV according to the design parameters of the Proton Linac at FAIR. The development of an adequate beam dynamics design was done in close collaboration with the IAP resonator design team. A constant vane curvature radius and at the same time a flat voltage distribution along the RFQ was reached by implantation of the modulated vane geometry into CST Microwave Studio RF field simulations. Points of reference for the beam dynamics layout are the beam dynamics designs of C. Zhang* and A. Lombardi**. The Code RFQGen*** was used for the beam dynamics simulations. In order to increase the transmission and to reduce the longitudinal and transversal exit emittances, the evolution of the modulation parameter m within the first 90 cells was investigated in detail. This paper presents the simulation results of this study.
* Chuan Zhang, Beam Dynamics for the FAIR Proton-Linac RFQ, IPAC 2014, Dresden
** C. Rossi et al., The Radiofrequency Quadrupole Accelerator for the LINAC4, LINAC08, Victoria, BC, Canada
***L. Young, RFQGen User Guide, Los Alamos Scientific Lab., NM (USA), 2016.

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TUPVA089

Preliminary Design of a High-intensity Continuous-wave Deuteron RFQ

rfq, emittance, simulation, focusing

2287

X. Liu
RIKEN, Saitama, Japan
O. Kamigaito, N. Sakamoto, K. Yamada
RIKEN Nishina Center, Wako, Japan

Funding: This work has been funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan)
A high-intensity deuteron linear accelerator is currently beding studied as a promising candidate to treat high-level radioactive wastes through the nuclear transmutation process. This paper presents the study on a design of a 75.5 MHz, 400 mA, continuous-wave deuteron radio-frequency quadrupole (RFQ), which is proposed as the front-end of such a linear accelerator. The results of the beam dynamics simulation suggest that the designed RFQ can accelerate a 400-mA deuteron beam from 100 keV to 2.5 MeV with a transmission rate of 92 ~ 93.3%, depending on the assumed input transverse emittance.

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TUPVA090

Performance and Status of the J-PARC Accelerators

operation, klystron, ion-source, extraction

2290

K. Hasegawa, N. Hayashi, M. Kinsho, H. Oguri, K. Yamamoto, Y. Yamazaki
JAEA/J-PARC, Tokai-mura, Japan
Y. Hori, N. Yamamoto
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
T. Koseki, F. Naito
KEK, Tokai, Ibaraki, Japan

The J-PARC is a high intensity proton facility and the accelerator consists of a 400 MeV linac, a 3 GeV Rapid Cycling Synchrotron (RCS) and a Main Ring Synchrotron (MR). We have taken many hardware upgrades. The beam powers for the neutrino experiment and hadron experiment from the MR have been steadily increased by tuning and reducing beam losses. The designed 1 MW equivalent beam was demonstrated and user program was performed at 500 kW from the RCS to the neutron and muon experiments. We have experienced many failures and troubles, however, to impede full potential and high availability. In this report, operational performance and status of the J-PARC accelerators are presented.

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TUPVA094

Beam Dynamics Design of the Muon Linac High-Beta Section

simulation, emittance, impedance, target

2304

Y. Kondo, K. Hasegawa
JAEA/J-PARC, Tokai-mura, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan
T. Mibe, M. Otani, M. Yoshida
KEK, Tsukuba, Japan

Funding: This work was supported by JSPS KAKENHI Grant Number 16H03987.
A muon linac development for a new muon g-2 experiment is now going on at J-PARC. Muons from the muon beam line (H-line) at the J-PARC MLF are once stopped in an silica aerojel target and room temperature muoniums are evaporated from the aerogel. They are dissociated with laser (ultra slow muons), then accelerated up to 212 MeV using a linear accelerator. For the accelerating structure from 40 MeV, disk-loaded traveling-wave structure is applicable because the particle beta is more than 0.7. The structure itself is similar to that for electron linacs, however, the cell length should be harmonic to the increase of the particle velocity. In this paper, the beam dynamics design of this muon linac using the disk-loaded structure is described.

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TUPVA096

Detection of H⁰ Particles in MEBT2 Chicane of J-PARC Linac

vacuum, ion, diagnostics, detector

2308

J. Tamura, H. Ao, T. Maruta, A. Miura, T. Morishita, K. Okabe, M. Yoshimoto
JAEA/J-PARC, Tokai-mura, Japan
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
Y. Nemoto
Nippon Advanced Technology Co., Ltd., Tokai, Japan

In the Japan Proton Accelerator Research Complex (J-PARC), H⁰ particles generated by collisions of accelerated H⁻ beams with residual gases are considered as one of the key factors of the residual radiation in the high energy accelerating section of the linac. To diagnose the H⁰ particles, the new beam line for analyzing H⁰ and H⁻ particles was installed in the second medium energy beam transport (MEBT2), which is the matching section from the separated-type drift tube linac (SDTL) to the annular-ring coupled structure linac (ACS). The analysis line consists of four dipole magnets for giving the H⁻ beam chicane orbit, and a wire scanner monitor (WSM) for measuring the horizontal shift of the H⁻ beam. To detect the H⁰ particles, a carbon plate is installed to the WSM. In the beam commissioning, we detected the signals of H⁰ particles penetrating the plate and observed the transition of the signal with various vacuum condition in the SDTL section.

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TUPVA097

First Trial of the Muon Acceleration for J-Parc Muon g-2/edm Experiment

rfq, acceleration, diagnostics, target

2311

R. Kitamura
University of Tokyo, Tokyo, Japan
S. Bae, B. Kim
SNU, Seoul, Republic of Korea
Y. Fukao, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura
KEK, Tsukuba, Japan
K. Hasegawa, Y. Kondo
JAEA/J-PARC, Tokai-mura, Japan
H. Iinuma
Ibaraki University, Hitachi, Ibaraki, Japan
K. Ishida
RIKEN Nishina Center, Wako, Japan
G.P. Razuvaev
BINP SB RAS, Novosibirsk, Russia
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Funding: This work was supported by JSPS KAKENHI Grant Number 16H03987 and 16J07784.
J-PARC E34 experiment aims to measure the muon g-2 and EDM precisely with the unique approach. The muon acceleration is the one of the most critical technique to achieve the goal of the sensitivity. The world's first muon LINAC is planed toward the muon acceleration to 212 MeV in J-PARC. The first trial of the muon acceleration is planed in the early 2017 with the J-PARC prototype RFQ ahead of the construction of the actual muon LINAC. The slow muon source is required for the RFQ test, since the input energy of the RFQ is 5.6 keV. The slow muon produced by the deceleration using the thin aluminum foil was observed. The demonstration of the muon extraction with 7 keV by the electrostatic accelerator called SOA lens was also done. The low-energy muon beam profile monitor (muon BPM) for the measurement of the beam intensity and profile in order to estimate the beam emittance was tested using the surface muon beam. The simulation for the beam emittance measurement has been developed. In this paper, the latest preparation status for the RFQ and the prospects for the muon acceleration test in J-PARC will be presented.

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TUPVA098

Beam Commissioning of Transport Line LRBT of CSNS

cavity, emittance, DTL, beam-transport

2314

Z.P. Li, Y. Li, J. Peng, S. Wang
IHEP, Beijing, People's Republic of China

The linac to ring beam transport line (LRBT) connects the 80 MeV linac and the 1.6 GeV rapid cycling synchrotron (RCS) of the China spallation neutron source (CSNS). The linac and LRBT commissioning have been in progress in the past months and the H⁻ beam has been accelerated to the kinetic energy of 60MeV this April. The H⁻ beam in LRBT which was measured and commissioned transported through the long beam line with low loss. The beam commissioning process and results of LRBT are presented and discussed.

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TUPVA100

High Power Conditioning and First Beam Acceleration of the CSNS DTL-1

DTL, cavity, vacuum, acceleration

2320

Y. Wang, A.H. Li, B. Li, J. Peng, P.H. Qu, X.L. Wu
CSNS, Guangdong Province, People's Republic of China
Q. Chen, M.X. Fan, K.Y. Gong, H.C. Liu
IHEP, Beijing, People's Republic of China

The CSNS DTLs are divided into 4 cavities. The DTL-1 was transferred and installed in the CSNS Linac tunnel in August of 2015. The RF high power conditioning of DTL-1 started in December 2015 and ended in February 2016. At the end, we finished DTL-1 high power conditioning mission with peak power 1.5MW (1.1 times design value), 1.625% duty factor (650us, 25Hz). And the first beam has been successfully accelerated to the design value 21.6MeV with nearly 100% transmission efficiency. In this paper, the details of conditioning process were presented and one severe RF discharge breakdown was described specifically, which occurred during high power conditioning.

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TUPVA101

Study of Different Models on DTL for CSNS

DTL, emittance, alignment, simulation

2322

Y. Yuan, Z.P. Li, J. Peng
IHEP, Beijing, People's Republic of China

China Spallation Neutron Source (CSNS) is a high intensity accelerator based facility. Its accelerator consists of an H⁻ injector and a proton Rapid Cycling Synchrotron (RCS). The injector includes the front end and linac. The RFQ accelerates the beam to 3MeV, and then the Drift Tube Linac (DTL) accelerates it to 80MeV. A Medium Energy Beam Transport (MEBT) matches RFQ and DTL, and the DTL consists of four tanks (DTL1, 2, 3, 4). A Linac to Ring Beam Transport (LRBT) matches DTL and RCS, also decreases beam energy spread. Commissioning of the first three DTL tank and LRBT straight section have been almost accomplished in this run. This paper takes a beam dynamics simulation on beam transport in MEBT and DTL at different DTL accelerate models. Meanwhile, beam's central orbit deviation at DTL and LRBT straight section due to DTL mechanical cavity's alignment errors is studied with IMPACT-Z code.

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TUPVA103

Beam Dynamics Design of the 3MeV RFQ for BISOL Project

rfq, emittance, simulation, neutron

2328

H.P. Li, Q. Fu, P.P. Gan, Y.R. Lu, Z. Wang, K. Zhu
PKU, Beijing, People's Republic of China

The Beijing isotope separation online (BISOL) facility will be used to study the new physics and technologies at the limit of nuclear stability. The facility can be driven by a reactor or a deuteron accelerator. The driver accelerator for the BISOL facility aims to accelerate a 50 mA D⁺ beam to 40 MeV. As an injector for the downstream su-perconducting linac, a 4-vane RFQ operating at 162.5 MHz has been designed to accelerate the deuteron beam from 0.05 MeV to 3.0 MeV in CW mode. For the beam dynamics design of this high-intensity RFQ, a matched and equipartitioned design method is adopted in order to control beam loss. After the optimization, the simulated beam transmission efficiency is higher than 99%. The transverse normalized rms emittance growth is approxi-mately 12%. Detailed results of the beam dynamics as well as the error study of the RFQ are presented in this paper.

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TUPVA104

RF and Primary Beam Dynamics Design of a 325 MHz IH-DTL

DTL, cavity, proton, simulation

2332

Y. Lei, X. Guan, C.-X. Tang, R. Tang, X.W. Wang, Q.Z. Xing, S.X. Zheng
TUB, Beijing, People's Republic of China

An interdigital H-mode drift tube linac (IH-DTL), which is aimed at proton medical facilities, has been proposed and developing at Tsinghua University. Considering following 3 MeV RFQ in the platform of CPHS (Compact Pulse Hadron Source at Tsinghua University) and XiPAF (Xi‘an Proton Application Facility) project, the input energy of IH-DTL is 3 MeV and the RF frequency is 325 MHz. The proton beam can be accelerated from 3 MeV to 7 MeV and the peak current of the beam at the exit of the cavity is about 15 mA. In order to simplify the fabrication, A KONUS structure without focusing element in the cavity is chosen. The RF design of single CELL and the primary dynamics design is done. The co-iteration of dynamics simulation and RF calculation of whole cavity is undergoing.

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TUPVA105

Development Progress of the 7MeV Linac Injector for the 200MeV Synchrotron of Xi'an Proton Application Facility

rfq, DTL, ion, ion-source

2336

Q.Z. Xing, C.B. Bi, C. Cheng, D. Dan, C.T. Du, T.B. Du, X. Guan, Q.K. Guo, Y. Lei, K.D. Man, C.-X. Tang, R. Tang, D. Wang, X.W. Wang, H.Y. Zhang, S.X. Zheng
TUB, Beijing, People's Republic of China
W.Q. Guan, Y. He, J. Li
NUCTECH, Beijing, People's Republic of China
E.Y. Qu, B.C. Wang, Z.M. Wang, Y. Yang, C. Zhao
State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Shannxi, People's Republic of China

We present, in this paper, the development progress of the 7MeV Linac for the 200MeV synchrotron of the Xi'an Proton Application Facility (XiPAF). The 7 MeV linac injector is composed of the 50 keV negative hydrogen ion source, Low Energy Beam Transport line (LEBT), 3 MeV four-vane type Radio Frequency Quadrupole (RFQ) accelerator, 7 MeV Alvarez-type Drift Tube Linac (DTL), and the corresponding RF power source system. The 2.45 GHz microwave-driven Cesium-free Electron Cyclotron Resonance (ECR) source and LEBT will be commissioned in this year, and the peak current of the extracted H⁻ beam at the exit of the LEBT is expected to be 6 mA, with the output energy of 50 keV, maximum repetition rate of 0.5 Hz, beam pulse width of 10~40 microseconds and normalized RMS emittance of less than 0.2 PI mm mrad. Furthermore, the construction status of the RFQ accelerator and DTL accelerator will be presented in this paper.

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TUPVA116

Commissioning of the New Heavy Ion Linac at the NICA Project

rfq, ion, ion-source, heavy-ion

2362

A.V. Butenko, D.E. Donets, A.D. Kovalenko, K.A. Levterov, D.A. Lyuosev, A.A. Martynov, V.V. Mialkovskiy, D.O. Ponkin, K.V. Shevchenko, I.V. Shirikov, A.O. Sidorin
JINR/VBLHEP, Dubna, Moscow region, Russia
A.M. Bazanov, B.V. Golovenskiy, V. Kobets, V.A. Monchinsky, A.V. Smirnov
JINR, Dubna, Moscow Region, Russia
H. Höltermann, D. Mäder, H. Podlech, U. Ratzinger, A. Schempp
BEVATECH, Frankfurt, Germany

The new accelerator complex Nuclotron-based Ion Collider fAcility (NICA) is now under development and construction at JINR, Dubna. This complex is assumed to operate using two injectors: modernized old Alvarez-type linac LU-20 as the injector of light polarized ions and a new Heavy Ion Linear Accelerator HILAc - injector of heavy ions beams. The new heavy ion linac accelerate ions with q/A values above 0.16 to 3.2 MeV/u is under commissioning. The main components are 4-Rod-RFQ and two IH drift tube cavities is operated at 100.6 MHz. Main results of the HILAc commissioning with carbon beam from the laser ion source are discussed.

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TUPVA117

Commissioning of New Light Ion RFQ Linac and First Nuclotron Run with New Injector

rfq, ion, operation, proton

2366

A.V. Butenko, A.M. Bazanov, D.E. Donets, K.A. Levterov, D.A. Lyuosev, A.A. Martynov, V.V. Mialkovskiy, D.O. Ponkin, R.G. Pushkar, V.V. Seleznev, K.V. Shevchenko, I.V. Shirikov, A.O. Sidorin
JINR/VBLHEP, Dubna, Moscow region, Russia
S.V. Barabin, A.V. Kozlov, G. Kropachev, T. Kulevoy, V.G. Kuzmichev
ITEP, Moscow, Russia
A. Belov
RAS/INR, Moscow, Russia
V.V. Fimushkin, B.V. Golovenskiy, A. Govorov, V. Kobets, A.D. Kovalenko, V.A. Monchinsky, A.V. Smirnov, G.V. Trubnikov
JINR, Dubna, Moscow Region, Russia
S.M. Polozov
MEPhI, Moscow, Russia

The new accelerator complex Nuclotron-based Ion Collider fAcility (NICA) is now under development and construction at JINR, Dubna. This complex is assumed to operate using two injectors: the Alvarez-type linac LU-20 as injector of light ions, polarized protons and deuterons and a new linac HILAc - injector of heavy ions beams. Old DC for-injector of the LU-20, which operated from 1974, is replaced by the new RFQ accelerator, which was commissioned in spring 2016. The first Nuclotron technological run with new fore-injector was performed in June 2016. Beams of D⁺ and H²⁺ were successfully injected and accelerated in the Nuclotron ring. Main results of the RFQ commissioning and the first Nuclotron run with new for-injector is discussed in this paper.

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TUPVA121

Shielding Calculations for the Commissioning Beam Dump During the First Stage Beam Commissioning of the ESS Warm Linac

shielding, proton, neutron, DTL

2376

K. Batkov, L. Tchelidze
ESS, Lund, Sweden

Starting operations in 2019, the European Spallation Source will be a long pulsed neutron source powered by a 5 MW proton beam impinging on a rotating tungsten target. This study describes the results of shielding calculations performed to determine necessary shielding configuration during various steps of first stage beam commissioning of the ESS Linac. The first stage commissioning is divided in four steps with different beam energy, up to maximum 74 MeV. The commissioning beam dump shielding assessment is presented for each step of first stage commissioning and different beam parameters (energies, repetition rates, pulse lengths and currents).

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TUPVA125

LINAC5: A Quasi-Alvarez LINAC for BioLEIR

ion, rfq, DTL, quadrupole

2385

J.M. Garland, J.-B. Lallement, A.M. Lombardi
CERN, Geneva, Switzerland

LINAC5 is a new linac proposed for the acceleration of light ions with Q/A = 1/3 to 1/4 for medical applications within the BioLEIR (Low Energy Ion Ring) design study at CERN. We propose a novel quasi-Alvarez drift-tube linac (DTL) accelerating structure design for LINAC5, which can reduce the length of a more conventional DTL structure, yet allows better beam focussing control and flexibility than the inter-digital H (IH) structures typically used for modern ion acceleration. We present the main sections of the linac with total length 12 m, including a 202 MHz radio frequency quadrupole (RFQ) a matching medium energy beam transport (MEBT) and a 405 MHz quasi-Alvarez accelerating section with an output energy of 4.2 MeV/u. Permanent magnet quadrupoles are proposed for use in the quasi-Alvarez structure to improve the compactness of the design and increase the efficiency. Lattice design considerations, multi-particle beam dynamics simulations and RFQ and radio frequency (RF) cavity designs are presented.

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TUPVA131

Beam Commissioning Planning Updates for the ESS Linac

target, DTL, rfq, dipole

2407

D.C. Plostinar, M. Eshraqi, R. Miyamoto, M. Muñoz
ESS, Lund, Sweden

The European Spallation Source (ESS) is a flagship research facility currently under construction in Lund, Sweden. It is driven by a 2 GeV linac, accelerating a 62.5 mA proton beam at a 4% duty cycle. With an average beam power of 5 MW, when completed the ESS linac will become the world's most powerful. In this paper we summarise the latest beam commissioning plans from the ion source to the target, highlighting the individual phases, the beam dynamics challenges as well as the scheduling strategy.

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TUPVA138

Status of the Warm Front End of PIP-II Injector Test

rfq, kicker, ion, ion-source

2421

A.V. Shemyakin, M.L. Alvarez, R. Andrews, C.M. Baffes, J.-P. Carneiro, A.Z. Chen, P. Derwent, J.P. Edelen, D. Frolov, B.M. Hanna, L.R. Prost, G.W. Saewert, A. Saini, V.E. Scarpine, V.L. Sista, J. Steimel, D. Sun, A. Warner
Fermilab, Batavia, Illinois, USA
V.L. Sista
BARC, Mumbai, India

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DEAC02-07CH11359 with the United States Department of Energy
The Proton Improvement Plan II (PIP-II) at Fermilab is a program of upgrades to the injection complex. At its core is the design and construction of a CW-compatible, pulsed H⁻ SRF linac. To validate the concept of the front-end of such machine, a test accelerator known as PIP-II Injector Test is under construction. It includes a 10 mA DC, 30 keV H⁻ ion source, a 2 m-long Low Energy Beam Transport (LEBT), a 2.1 MeV CW RFQ, followed by a Medium Energy Beam Transport (MEBT) that feeds the first of 2 cryomodules increasing the beam energy to about 25 MeV, and a High Energy Beam Transport section (HEBT) that takes the beam to a dump. The ion source, LEBT, RFQ, and initial version of the MEBT have been built, installed, and commissioned. This report presents the overall status of the warm front end.

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TUPVA140

Space charge effects of catch-up collision in a CW double-pass proton linac

simulation, proton, cavity, space-charge

2429

Y. Tao, K. Hwang, J. Qiang
LBNL, Berkeley, California, USA

Recirculating superconducting proton linac has an advantage to reduce the number of cavities and the resulting accelerator construction/operation costs. Beam dynamics simulations were done recently in a double pass recirculating proton linac using a single bunch. For continuous wave (CW) operation, the high energy proton beam bunch during the second pass will catch up and collide with the low energy proton bunch at a number of locations inside the superconducting linac. In this paper, we report on the study of the space-charge effects during a collision on both beams through the rest of the linac.

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TUPVA147

Progress on the Proton Power Upgrade of the Spallation Neutron Source

target, cryomodule, klystron, proton

2445

M.S. Champion, R.A. Dean, J. Galambos, M.P. Howell, M.A. Plum, B.W. Riemer
ORNL, Oak Ridge, Tennessee, USA

Funding: Work performed at (or work supported by) Oak Ridge National Laboratory, which is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
The Proton Power Upgrade Project is underway at the Spallation Neutron Source at Oak Ridge National Laboratory and will double the proton beam power capability from 1.4 MW to 2.8 MW to provide increased neutron intensity at the first target station and to support future operation of the second target station. This will be accomplished by increasing the beam energy to 1.3 GeV and the beam current to 38 mA (average during the macro-pulse). Installation of 28 additional superconducting cavities and their associated technical systems will provide for the energy increase. Increased beam loading throughout the accelerator will be accommodated primarily through the use of existing margin in the RF systems and the installation of 700 kW klystrons to power the new superconducting cavities. Upgrades of a few existing RF stations may also be needed. The injection and extraction regions of the accumulator ring will be upgraded, a ring to second target station tunnel stub will be constructed, and a 2 MW target will be developed for the first target station. The project anticipates attainment of Critical Decision 1 in 2017 to ratify the project conceptual design and cost range.

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TUPVA153

Accelerator-Based Education Activities at JINR

vacuum, controls, electron, radiation

2455

M.A. Nozdrin, D. Belozerov, K. Gikal, V. Kobets, S. Pakuliak, V. Shabratov, G. Shirkov, D. Shvidkiy, K. Verlamov, A. Zhemchugov, D. Zlydenny
JINR, Dubna, Moscow Region, Russia

Professional practice is essential to train an engineer. However, many activities are impossible to run at high school, especially if they require sophisticated equipment such as accelerators. A series of practical engineering courses is being set up at the Joint Institute for Nuclear Research to overcome these difficulties while educating students from the JINR Member States. A dedicated 'training' beamline of the Linac-200 electron accelerator is being constructed to practice the beam management and diagnostics, including the operation of standard beamline elements such as a bending dipole, quadrupoles, a sextupole and steerers. Various types of particle detectors can be used in the beam area as well in order to study the passage of electrons and photons through matter and to learn about the detector operation and properties. The practice at the beam will be accompanied by a series of hands-on trainings on radiation protection, vacuum and RF technology, electronics and metrology.

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WEOAA1

Commissioning of SPIRAL2 CW RFQ and Linac

rfq, ion, proton, cryomodule

2462

R. Ferdinand, P.-E. Bernaudin, P. Bertrand, M. Di Giacomo, H. Franberg, A. Ghribi, O. Kamalou, J.-M. Lagniel, G. Normand, A. Savalle, F. Varenne
GANIL, Caen, France
D. Uriot
CEA/DRF/IRFU, Gif-sur-Yvette, France

The SPIRAL2 88 MHz CW RFQ is designed to accelerate light and heavy ions with A/Q from 1 to 3 at 0.73 MeV/A. The nominal beam intensities are up to 5 mA CW for both proton and deuteron beams and up to 1 mA CW for heavier ions. The design foresees almost 100% transmission for all ions at nominal beam current and emittance. Beam commissioning of the RFQ and linac cool down started already. The specifications have been achieved within the measurement precision for the different ions accelerated yet. This paper describes the beam commissioning strategy, the measurement results in both transverse and longitudinal planes and the success-fully first cryogenic tests of the linac.

Slides WEOAA1 [11.515 MB]

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WEOAA2

Status of Radioactive Ion Beam Post-Acceleration at CERN-ISOLDE

cryomodule, cryogenics, experiment, operation

2466

Y. Kadi, W. Andreazza, J. Bauche, A. Behrens, A.P. Bernardes, J.A. Ferreira Somoza, F. Formenti, M.A. Fraser, M.J. Garcia Borge, N. Guillotin, K. Johnston, G. Kautzmann, Y. Leclercq, M. Martino, A. Miyazaki, R. Mompo, A. Papageorgiou Koufidou, O. Pirotte, J.A. Rodriguez, S. Sadovich, E. Siesling, M. Therasse, D. Valuch, W. Venturini Delsolaro
CERN, Geneva, Switzerland

Funding: We acknowledge funding from the Belgian Big Science program of the FWO (Research Foundation Flanders) and the Research Council K.U. Leuven.
The HIE-ISOLDE project* (High Intensity and Energy ISOLDE) reached an important milestone in September 2016 when the first physics run was carried out with radioactive beams at 6 MV/m. This is the first stage in the upgrade of the REX post-accelerator, whereby the energy of the radioactive ion beams was increased from 3 to 5.5 MeV per nucleon. The facility will ultimately be equipped with four high-beta cryomodule that will accelerate the beams up to 10 MeV per nucleon for the heaviest isotopes available at ISOLDE. The first 2 cryomodules of the new linac, hosting each five superconducting cavities and one solenoid, were commissioned in August 2016. Besides demonstrating the experimental capabilities of the facility, this successful first run validated the technical choices of the HIE ISOLDE team and provided a fitting reward for eight years of rigorous R&D efforts. At the start of 2018, HIE-ISOLDE is expected to complete the energy upgrade, reaching 10 MeV/u and becoming an attractive facility for a wide variety of experiments. This contribution will focus on the results of the commissioning and on the main technical issues that were highlighted.
* M.J.G. Borge and K. Riisager (2016), HIE-ISOLDE, the project and the physics opportunities, European Physical Journal A 52: 334, DOI: 10.1140/epja/i2016-16334-4

Slides WEOAA2 [7.659 MB]

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WEPAB037

Two-Bunch Operation at the FERMI FEL Facility

wakefield, laser, FEL, electron

2663

G. Penco, E. Allaria, S. Bassanese, P. Cinquegrana, S. Cleva, M.B. Danailov, A.A. Demidovich, S. Di Mitri, M. Ferianis, G. Gaio, D. Gauthier, L. Giannessi, M. Predonzani, F. Rossi, E. Roussel, S. Spampinati, M. Trovò
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
L. Giannessi
ENEA C.R. Frascati, Frascati (Roma), Italy
E. Roussel
PhLAM/CERLA, Villeneuve d'Ascq, France

FERMI is a linac-driven free electron laser (FEL) based upon the High Gain Harmonic Generation (HGHG) scheme. In standard conditions a bunch of 700 pC of charge with sub mm-mrad emittances is accelerated to 1.2-1.5GeV in a normal conducting S-band linac and drives FEL-1 or FEL-2 undula-tor line, which lase respectively in the range 100-20nm or 20-4nm. A number of two-color schemes have been implemented at FERMI for pump/probe experiments, all consisting in making two portions of the same electron bunch lase at two different wavelengths, with a time-separation from 0 to few hundreds of fs. In order to increase the time separation to ns and tens of ns we have explored the acceleration of two inde-pendent electron bunches separated by multiple of the linac main radio-frequency period, i.e. 333ps. Measure-ments and characterization of this two-bunch mode oper-ation are presented, including trajectory control, impact of longitudinal and transverse wakefields on the trailing bunch and manipulation of the longitudinal phase space.

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WEPAB039

Development Perspectives at FERMI

FEL, laser, electron, experiment

2666

M. Svandrlik, E. Allaria, L. Badano, F. Bencivenga, C. Callegari, F. Capotondi, F. Cilento, P. Cinquegrana, M. Coreno, I. Cudin, G. D'Auria, M.B. Danailov, R. De Monte, G. De Ninno, P. Delgiusto, A.A. Demidovich, M. Di Fraia, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, P. Furlan Radivo, G. Gaio, D. Gauthier, F. Gelmetti, L. Giannessi, F. Iazzourene, S. Krecic, M. Lonza, N. Mahne, M. Malvestuto, C. Masciovecchio, M. Milloch, F. Parmigiani, G. Penco, A. Perucchi, L. Pivetta, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, P. Rebernik Ribič, F. Rossi, E. Roussel, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

FERMI is the seeded Free Electron Laser (FEL) user facility at the Elettra laboratory in Trieste, operating in the ultraviolet to soft X-rays spectral range; the radiation produced by the seeded FEL is characterized by a number of desirable properties, such as wavelength stability, low temporal jitter and longitudinal coherence. In this paper, after an overview of the FEL performances, we will present the development plans under consideration for the next 3 to 5 years. These include an upgrade of the linac and of the existing FEL lines, the possibility to perform multipulse experiments in different configurations and an Echo Enabled Harmonic Generation (EEHG) experiment on FEL-2, the FEL line extending to 4 nm (310 eV).

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WEPAB044

Construction and Commissioning of Direct Beam Transport Line for PF-AR

injection, beam-transport, vacuum, operation

2678

N. Higashi, S. Asaoka, K. Furukawa, K. Haga, K. Harada, T. Higo, T. Honda, H. Honma, N. Iida, H. Iwase, K. Kakihara, T. Kamitani, M. Kikuchi, Y. Kishimoto, Y. Kobayashi, K. Kodama, K. Kudo, T. Kume, K. Mikawa, T. Mimashi, F. Miyahara, H. Miyauchi, S. Nagahashi, H. Nakamura, N. Nakamura, T. Natsui, K.N. Nigorikawa, Y. Niwa, T. Nogami, T. Obina, Y. Ogawa, M. Ono, T. Ozaki, H. Sagehashi, T. Sanami, M. Sato, M. Satoh, T. Suwada, M. Tadano, T. Tahara, R. Takai, H. Takaki, S. Takasaki, M. Tanaka, Y. Tanimoto, M. Tawada, N. Toge, T. Uchiyama, A. Ueda, Y. Yamada, M. Yamamoto, M. Yoshida
KEK, Ibaraki, Japan

PF-AR was constructed as an accumulator ring for TRISTAN, and in the KEKB era it has been revitalized as a 6.5 GeV synchrotron radiation source. The injection energy was 3 GeV and the beam was accelerated to 6.5 GeV prior to the user run. The original beam transport line (BT) from the LINAC to the PF-AR shared its upstream part with the the BT line of KEKB High Energy Ring (HER). The injection-mode change from PF-AR to HER or vice versa needs about 10 minutes for the magnet cycling procedure of the shared part. In SuperKEKB, the upgrade of KEKB, the lifetime of HER is about 10 minutes. The mode-switch operation of the BT is, therefore, not allowed for maintaining the highest luminosity of the SuperKEKB. In order to avoid this problem, a new 6.5 GeV BT line dedicated to PF-AR has been constructed. This also enables the top-up injection for the user run. The commissioning of the new BT line has been completed in this March, and now the first user run has been operated successfully.

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WEPAB045

Development of Dedicated Linac and Booster for KEK PF

booster, operation, lattice, injection

2681

N. Higashi, K. Harada, Y. Kobayashi, S. Nagahashi, N. Nakamura, A. Ueda
KEK, Ibaraki, Japan

KEK Photon Factory (PF) is a major light source facility in Japan. The injector of PF is KEK LINAC and it is shared with other three rings; PF-AR, SuperKEKB HER (High Energy Ring) and LER (Low Energy Ring). Due to the large electricity consumption, all accelerators in KEK are shut down during every summer for about 3 months. In 2017, because of the LINAC upgrade for SuperKEKB Phase 2 operation, the summer shutdown will be extended to about 5 months. On the other hand, the PF users always strongly wish the shorter shutdown and longer operation. Especially the structural biology users require the ability for the measurement within about 2 weeks after the irregular sample manufacture throughout the year. In order to satisfy these requests, the independent injector system is required for the realization of such longer operation. The examined system consists of an about 100 MeV small linac and a booster ring in the present PF ring tunnel. We show the results of the feasibility study for the independent injector system for the PF ring.

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WEPAB058

Commissioning Status of the Dalian Cohernet Light Source

FEL, laser, electron, undulator

2709

G.L. Wang
DICP, Dalian, People's Republic of China

The Dalian Coherent Light Source (DCLS) is a seeded FEL user facility working at 50-150 nm, now under commissioning in Dalian, China. The facility consists of a 300 MeV normal-conducting S-band linear accelerator (LINAC) and two undulator beamlines. The first beam-line (FEL-1) will provide picosecond FEL radiation with the pulse energy up to several hundreds micro-joule, the second beam-line (FEL-2) will be a femtosecond and polarization FEL. The LINAC and FEL-1 beam-line construction was complete by the summer of 2016, the installation of FEL-2 is in preparation. High power RF conditioning of the LINAC started in August 2016 and the beam commissioning initiated 3 months later. This article describes the commissioning status of DCLS, reports on the goals achieved so far.

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WEPAB071

Single Bunch Bucket Selection Injection Modes in the ALBA Storage Ring

injection, operation, storage-ring, electron

2744

R. Muñoz Horta, G. Benedetti, D. Lanaia, J. Moldes, F. Pérez, M. Pont, L. Torino
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

The ALBA Synchrotron has been operating routinely in top-up mode since 2014, performing reinjections of multi-bunches every 20 minutes. Recently, the control of the timing has been upgraded to allow single bunches to be injected into any storage ring bucket and therefore to top up the stored current also in single bunch injector mode. In addition, by means of a specific algorithm, a new injection mode called Single Bunch Bucket Selection (SBBS) has been developed to provide any kind of filling pattern in the ALBA storage ring. This mode controls independently the amount of current injected into each bucket, and injects first into those buckets with lowest charge. When used in top-up mode, SBBS keeps the charge distribution of the filling pattern with a uniformity below 10%. The improved flexibility and stability of the filling pattern increases the scope of research for the ALBA experiments and for machine studies development. The implementation of the new injection modes and their performance are presented.

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WEPAB077

The Soft X-Ray Laser Project at MAX IV

laser, FEL, undulator, electron

2760

S. Werin, J. Andersen, F. Curbis, L. Isaksson, M. Kotur, F. Lindau, E. Mansten, D. Olsson, H. Tarawneh, P.F. Tavares, S. Thorin
MAX IV Laboratory, Lund University, Lund, Sweden
S. Bonetti, A. Nilsson
Stockholm University, Stockholm, Sweden
V.A. Goryashko
Uppsala University, Uppsala, Sweden
P. Johnsson
Lund University, Lund, Sweden
M. Larsson, P. Salén
FYSIKUM, AlbaNova, Stockholm University, Stockholm, Sweden
O. Tjernberg
KTH Physics, Stockholm, Sweden

A soft x-ray laser beamline utilising FEL technology is being designed for the Short Pulse Facility (SPF) at the MAX IV Laboratory. A conceptual design study has been started following on the scientific case already prepared in collaboration between several Swedish Universities and driven by a strong (Swedish) user demand [*]. The baseline goal of the SXL beamline is to generate intense and short pulses in the range 1-5 nm (1-0.2 keV). The system is building on the MAX IV linac system, already today providing 3 GeV and pulses compressed to 100 fs for other applications within the SPF. As a special feature we foresee a variety of pump-probe capabilities. We here describe design issues and solutions for the accelerator and FEL system.
* http://frielektronlaser.se/onewebmedia/SXL_science_case₁61102.pdf

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WEPAB087

TARLA: The First Facility of Turkish Accelerator Center (TAC)

electron, cavity, FEL, laser

2776

A.A. Aksoy, A.A. Aydin, C. Kaya
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
B. Ketenoğlu, O. Yavaş
Ankara University, Faculty of Engineering, Tandogan, Ankara, Turkey

Funding: Work supported by Ministry of Development of Turkey
Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) is proposed as first accelerator based infrastructure in Turkey as a first step Turkish Accelerator Center (TAC). The facility under construction at Institute of Accelerator Technologies of Ankara University since 2012. Based superconducting technology, TARLA accelerator will offer a multi-experiment facility providing various accelerator-based radiation sources for the users coming from different fields like physics, chemistry, biology, material sciences, medicine and nanotechnology. Two of the planed free-electron laser (FEL) beamlines of TARLA will provide Continuous Wave (CW) tunable radiation of high brightness in the mid- and far-infrared regime. In addition a Bremmstrahlung radiation station is proposed within current scope of TARLA. In this paper current status of facility is presented.

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WEPAB088

Dark Current Studies in the CLARA Front-End Injector

gun, solenoid, simulation, electron

2779

F. Jackson, I.R. Gessey, J.W. McKenzie, B.L. Militsyn, P.J. Tipping
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

At STFC Daresbury a new facility CLARA (Compact Linear Accelerator for Research and Applications) is being designed and constructed. The principal aim of CLARA is advanced Free Electron Laser research. Halo and dark current in CLARA is a concern for damage to the undulator, and other applications of the machine. Recently the front end (gun, diagnostics, first linac) of CLARA has been installed including some collimation to mitigate halo effects. Beam halo may arise from gun field emission or due to beam dynamics in the early stages of acceleration, which may achieve the same energy as the core beam and thus may be transported to the undulator. The code CST is used to study the gun field emission. The code ASTRA is used to study the transport of field emission through the front end, including the effectiveness of collimators. Machine measurements of dark current are compared against these simulations.

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WEPAB122

Experimental Demonstration of Ballistic Bunching with Dielectric-Lined Waveguides at Pitz

electron, experiment, bunching, wakefield

2857

F. Lemery
University of Hamburg, Hamburg, Germany
G.A. Amatuni, B. Grigoryan
CANDLE, Yerevan, Armenia
P. Boonpornprasert, Y. Chen, J.D. Good, M. Krasilnikov, O. Lishilin, G. Loisch, S. Philipp, H.J. Qian, Y. Renier, F. Stephan
DESY Zeuthen, Zeuthen, Germany
P. Piot
Fermilab, Batavia, Illinois, USA
P. Piot
Northern Illinois University, DeKalb, Illinois, USA

We report on the experimental demonstration of ballistic bunching of photoinjected, nC-scale electron bunches at the PITZ facility. In the experiment, electron bunches emanating from the photocathode were directly focused into a mm-scale dielectric-lined waveguide. The wakefield excited by the bunch acts back onto itself, leading to an energy modulation, which at a relatively low energy of 6~MeV, is converted into a density modulation before entering the linac ∼ 1~m downstream. We discuss the basic theory, experimental layout and results.

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WEPAB125

Crossbar H-Mode Drift-Tube Linac Design With Alternative Phase Focusing for Muon Linac

cavity, emittance, acceleration, dipole

2868

M. Otani, K. Futatsukawa
KEK, Tsukuba, Japan
K. Hasegawa, Y. Kondo
JAEA/J-PARC, Tokai-mura, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan
S.S. Kurennoy
LANL, Los Alamos, New Mexico, USA

Funding: This work was supported by JSPS KAKENHI Grant Number 15H03666.
A crossbar H-mode (CH) drift-tube linac (DTL) is one of alternatives for a low velocity part in a muon linac at the J-PARC E34 experiment. It will accelerate muons from v/c = 0.08 to 0.28 at an operational frequency of 324 MHz. In order to achieve higher acceleration efficiency and make cost lower, an alternative phase focusing (APF) scheme is adopted. In this poster, dynamics and cavity designs with computer calculations will be presented.

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WEPIK036

ERL Cryomodule Testing and Beam Capabilities

cavity, cryomodule, SRF, operation

3010

F. Furuta, N. Banerjee, J. Dobbins, R.G. Eichhorn, M. Ge, D.L. Hall, G.H. Hoffstaetter, M. Liepe, R.D. Porter, P. Quigley, D.M. Sabol, J. Sears, E.N. Smith, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

The main linac cryomodule (MLC) prototype is a key component for the Cornell-BNL ERL Test Accelerator (CBETA) project, which is a 4-turn FFAG ERL under construction at Cornell University. This novel cryomodule is the first SRF module ever to be fully optimized simul-taneously for high efficient SRF cavity operation and for supporting very high CW beam currents. Initial MLC testing has demonstrated that cavity performance and HOMs damping meet specification values. Recent, addi-tional tests have focused on RF field stability, and cavity microphonics. In this paper, we summarize the perfor-mance of this novel ERL cryomodule and evaluate its beam capabilities based on the measured performance.

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WEPIK084

Approximating Nonlinear Forces with Phase-Space Decoupling

simulation, octupole, proton, sextupole

3120

B.T. Folsom, E. Laface
ESS, Lund, Sweden

Beam tracking software for accelerators typically falls into two categories: fast envelope simulations limited to linear beam optics, and slower multiparticle simulations that can model nonlinear effects. To find a middle ground between these approaches, we introduce virtual coordinates in position and momentum which have a cross-dependency (i.e. p*=f(x) where x is an initial position and p* is a virtual projection of momentum onto the position axis).This technique approximates multiparticle simulations with a significant reduction in calculation cost.

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WEPVA004

Simulation of an Electromagnetic Field Excitation by a THz-pulse and Acceleration of an Electron Bunch in a Dielectric-loaded AXSIS Linac

electron, acceleration, injection, simulation

3253

K. Galaydych, R.W. Aßmann, U. Dorda, B. Marchetti, G. Vashchenko, I. Zagorodnov
DESY, Hamburg, Germany

Funding: The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 609920
The Attosecond X-ray Science: Imaging and Spectroscopy (AXSIS) experiment at DESY will use a dielectric loaded waveguide to accelerate electron bunches up to 15 MeV. Such a linac will be powered by a narrowband multicycle THz-pulse with a central frequency of 300 GHz. In this paper we focus on the reflection of the excited field at a pinhole, on the optimization of the bunch injection time and on the bunch dynamics in the acceleration process. The linac excitation by the THz-pulse and the bunch acceleration in the excited field are investigated using CST and ECHO simulations.

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WEPVA006

A Concept for Phase-Synchronous Acceleration of Microbunch Trains in DLA Structures at SINBAD

laser, electron, acceleration, simulation

3260

F. Mayet, R.W. Aßmann, J. Bödewadt, R. Brinkmann, U. Dorda, W. Kuropka, C. Lechner, B. Marchetti, J. Zhu
DESY, Hamburg, Germany
W. Kuropka, F. Mayet
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
J. Zhu
University of Hamburg, Hamburg, Germany

Funding: GBMF - Gordon and Betty Moore Foundation
The concept of dielectric laser accelerators (DLA) has gained increasing attention in accelerator research, because of the high achievable acceleration gradients (~GeV/m). This is due to the high damage threshold of dielectrics at optical frequencies. In the context of the Accelerator on a Chip International Program (ACHIP) we plan to inject electron bunches into a laser-illuminated dielectric grating structure. At a laser wavelength of 2 micro-meter the accelerating bucket is <1.5 fs. This requires both ultra-short bunches and highly stable laser to electron phase. We propose a scheme with intrinsic laser to electron synchronization and describe a possible implementation at the SINBAD facility (DESY). Prior to injection, the electron bunch is conditioned by interaction with an external laser field in an undulator. This generates a sinusoidal energy modulation that is transformed into periodic microbunches in a subsequent chicane. The phase synchronization is achieved by driving both the modulation process and the DLA with the same laser pulse. This allows scanning the electron bunch to laser phase and will show the dependence of the acceleration process on this delay.

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WEPVA007

Simulations and Plans for a Dielectric Laser Acceleration Experiment at SINBAD

laser, experiment, electron, simulation

3264

F. Mayet, R.W. Aßmann, U. Dorda, W. Kuropka, B. Marchetti, J. Zhu
DESY, Hamburg, Germany
W. Kuropka, F. Mayet
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
J. Zhu
University of Hamburg, Hamburg, Germany

Funding: GBMF - Gordon and Betty Moore Foundation
In this work we present the outline of an experimental setup for dielectric laser acceleration of relativistic electron bunches produced by the ARES linac under construction at the SINBAD facility (DESY Hamburg). The experiment will be performed as part of the Accelerator on a Chip International Program (ACHIP), funded by the Gordon and Betty Moore Foundation. At SINBAD we plan to test the acceleration of already pre-accelerated relativistic electron bunches in a laser-illuminated dielectric grating structure. In addition to the conceptual layout of the experiment we present first start-to-end simulation results for different ARES working points. The simulations are performed using a combination of the well known particle tracking code ASTRA and the self-consistent particle in cell code VSim.

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WEPVA008

Beam Dynamics in THz Dielectric Loaded Waveguides for the AXSIS Project

gun, injection, emittance, electron

3268

T. Vinatier, R.W. Aßmann, U. Dorda, B. Marchetti
DESY, Hamburg, Germany
F. Lemery
CFEL, Hamburg, Germany

In this paper, we investigate with ASTRA simulations the beam dynamics in dielectric-loaded waveguides driven by THz pulses, used as linac structure for the AXSIS project. We show that the bunch properties at the linac exit are very sensitive to the phase velocity of the THz pulse and are limited by the strong phase slippage of the bunch respective to it. We also show that some margins for instabilities of the injection phase into the linac structure are allowed. We finally demonstrate that the bunch properties are optimized when low frequencies (< 300 GHz) are used inside the linac, and that the longitudinal focal point can be put several tens of cm away from the linac exit thanks to ballistic bunching. However, a strong asymmetry in the bunch transverse sizes remains for which a solution is still to be found.

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WEPVA014

Status of R&D on New Superconducting Injector Linac for Nuclotron-NICA

proton, ion, simulation, injection

3282

G.V. Trubnikov, A.V. Butenko, N. Emelianov, A.O. Sidorin, E. Syresin
JINR, Dubna, Moscow Region, Russia
T.A. Bakhareva, M. Gusarova, T. Kulevoy, S.V. Matsievskiy, S.M. Polozov, A.V. Samoshin, N.P. Sobenin, D.V. Surkov, K.V. Taletskiy, S.E. Toporkov, V. Zvyagintsev
MEPhI, Moscow, Russia
A.A. Bakinowskaya, A.A. Marysheva, V.S. Petrakovsky, I.L. Pobol, A.I. Pokrovsky, D.A. Shparla, S.V. Yurevich, V.G. Zaleski
Physical-Technical Institute of the National Academy of Sciences of Belarus, Minsk, Belarus
M.A. Baturitski, S.A. Maksimenko
INP BSU, Minsk, Belarus
S.E. Demyanov
Scientific-Practical Materials Research Centre of the National Academy of Sciences of Belarus, Minsk, Belarus
V.A. Karpovich
BSU, Minsk, Belarus
T. Kulevoy, S.M. Polozov
ITEP, Moscow, Russia
A.A. Kurayev, V.V. Matbeenko, A.O. Rak
Belarus State University of Informatics and Radioelectronics (BSUIR), Minsk, Belarus
V.N. Rodionova
Belarussian State University, Scientific Research Institute of Nuclear Problems, Minsk, Belarus
A.O. Sidorin
Saint Petersburg State University, Saint Petersburg, Russia
V. Zvyagintsev
TRIUMF, Vancouver, Canada

The new collaboration of JINR, NRNU MEPhI, INP BSU, PTI NASB, BSUIR and SPMRC NASB starts in 2015 the project of linac-injector design in 2015. The goal of new linac is to accelerate protons up to 25 MeV (and up to 50 MeV at the second stage) and light ions to ~7.5 MeV/u for Nuclotron-NICA injection. Current results of the linac general design and development, beam dynamics simulations, SC cavities design and SRF technology development are presented in this report.

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WEPVA035

The PSB Operational Scenario with Longitudinal Painting Injection in the Post-LIU Era

injection, target, simulation, controls

3331

V. Forte, S.C.P. Albright, M.E. Angoletta, P. Baudrenghien, E. Benedetto, A. Blas, C. Bracco, C. Carli, A. Findlay, R. Garoby, G. Hagmann, A.M. Lombardi, B. Mikulec, M.M. Paoluzzi, J.L. Sanchez Alvarez, R. Wegner
CERN, Geneva, Switzerland

Longitudinal painting has been presented as an elegant technique to fill the longitudinal phase space at injection to the CERN PSB once it is connected with the new Linac4. Painting brings several advantages related to a more controlled longitudinal filamentation, lower peak line density and beating reduction, resulting in a smaller space-charge tune spread. This could be an advantage especially for high intensity beams (> 6·10¹² protons per bunch) to limit losses on the transverse acceptance of the machine. This paper presents an overview on the possible advantages of the technique for operational and test beams, taking care of the hardware limitations and possible failure scenarios.

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WEPVA036

The LHC Injectors Upgrade (LIU) Project at CERN: Proton Injector Chain

cavity, injection, impedance, proton

3335

K. Hanke, J. Coupard, H. Damerau, A. Funken, B. Goddard, A.M. Lombardi, D. Manglunki, S. Mataguez, M. Meddahi, B. Mikulec, G. Rumolo, R. Scrivens, E.N. Shaposhnikova, M. Vretenar
CERN, Geneva, Switzerland

The LHC Injectors Upgrade (LIU) project at CERN aims at delivering high brightness beams required by the LHC in the high-luminosity LHC (HLLHC) era. The project comprises a new H⁻ Linac (Linac4) as well as a massive upgrade of the PS Booster, PS and SPS synchrotrons. This paper gives an update of the activities regarding the proton injector chain. We present the target beam parameters, a brief status of the upgrade work per machine and the outcome of the recent reviews. The planning for the implementation of the hardware upgrades and the re-commissioning of the complex will also be discussed.

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WEPVA051

Power Converters for the ESS Warm Magnets

quadrupole, beam-transport, dipole, neutron

3372

R. Visintini, M. Cautero
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
G. Göransson, C.A. Martins, P.J. Torri
ESS, Lund, Sweden

In the framework of the Italian In-Kind Contribution (IKC) to the construction of the European Spallation Source (ESS), Elettra Sincrotrone Trieste is in charge of providing some key equipment for the accelerator. Among them, there are the magnets and the associated power converters for the Linac Warm Units (LWU), the High Energy Beam Transport (HEBT) dogleg, the Dump Line (DmpL) and the Accelerator to Target (A2T) sections of the neutron source. Magnets and their power converters are complementary parts of common systems. Their design cannot be totally separated, requiring iterations for an optimal solution that should include also power cable standardization. This work will describe the power converters' solutions adopted for the magnets of the above-mentioned sections. They comprise 4-Quadrant power converters for the correctors, compact DC power converters for the small quadrupole magnets and more powerful DC power converters for the dipole and large quadrupole magnets.

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WEPVA052

The Infrastructure for the Elettra Sincrotrone Trieste

storage-ring, FEL, operation, laser

3375

D. Zangrando, D. Baron, A. Buonanno, A. Galimberti, A. Martinolli, M. Miculin, D. Morelli
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

Elettra - Sincrotrone Trieste S.C.p.A. is a multidisciplinary international laboratory, specialized in generating high quality synchrotron and free-electron laser light and applying it in materials science. The main assets of the research centre are two advanced light sources, the electron storage ring Elettra and the free-electron laser (FEL) FERMI, continuously (H24) operated supplying light of the selected colour and quality to more than 30 experimental stations. In this paper, we are giving an overview on the status of the infrastructure plants devoted to ensuring the operation of Elettra and FERMI machines. We will also analyse the systems that mostly have impacted on the performance of both accelerators and their downtime.

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WEPVA059

Construction of the New Septum Magnet Systems for PF-Advanced Ring

septum, injection, vacuum, storage-ring

3398

A. Ueda, S. Asaoka, T. Honda, S. Nagahashi, N. Nakamura, T. Nogami, H. Takaki, T. Uchiyama
KEK, Ibaraki, Japan

From July 2016 we are constructing a new beam transport (BT) line for the Photon Factory Advanced Ring (PF-AR). The new BT line was designed to transport the full energy 6.5-GeV beam directly from the LINAC, and the top up injection will be possible for the PF-AR. We designed and produced new pulsed septum magnet systems for this project. Two pulsed septum magnets are used for the injection of the 6.5-GeV beam. The septum magnets were constructed with a passive type magnet, a copper eddy current shield and a silicon steel magnetic shield. The magnetic fields of these magnets have been measured by the search coil method. We paid attention to evaluating eddy current losses of the SUS beam duct in the magnetic field measurement.

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WEPVA082

Technical Overview of the SOLARIS Low-Conductivity Water Cooling System

synchrotron, operation, storage-ring, klystron

3449

P. Czernecki, P. Bulira, P. Gębala, J. Janiga, P. Klimecki
Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland

National Synchrotron Radiation Centre Solaris started operation in May 2015. In order to receive heat deposited in various synchrotron devices during operation, a low-conductivity water (LCW) cooling system was installed. To fulfill all tasks of cooling system at an acceptable cost of investment and maintenance certain technical and economic conditions, i.e.:installation materials, LCW quality, hydraulic balancing system, automation, control and diagnostics, including the planned service intervals, have to be met. Within this presentation the design, construction and operation of the LCW cooling system will be discussed.

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WEPVA090

The Vacuum System of MAX IV Storage Rings: Installation and Conditioning

vacuum, storage-ring, ion, synchrotron

3468

E. Al-Dmour, M.J. Grabski
MAX IV Laboratory, Lund University, Lund, Sweden

The installation of the vacuum system of the 3 GeV storage ring was started in November 2014 and finished in May 2015. In August 2015 the commissioning of the storage ring started, the first stored beam has been achieved on the 15th of September 2015. The installation of the vacuum system of the 1.5 GeV storage ring was done from September 2015 and the main part finished in December 2015, the connection to the Linac with the transfer line has been done in August 2016. In September 2016 the commissioning of the 1.5 GeV storage ring started with the first stored beam achieved on the 30th of September 2016. The vacuum system conditioning for the two rings was successful; the average dynamic pressure reduction and the increase in the lifetime with the accumulated beam dose is a demonstration of the good performance of the vacuum system. The installation procedure and the results of the conditioning together with the latest developments are introduced here.

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WEPVA138

The RaDIATE High-Energy Proton Materials Irradiation Experiment at the Brookhaven Linac Isotope Producer Facility

target, proton, radiation, experiment

3593

K. Ammigan, P. Hurh, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
A. Amroussia, C.J. Boehlert
Michigan State University, East Lansing, Michigan, USA
M.S. Avilov, F. Pellemoine
FRIB, East Lansing, USA
M. Calviani, E. Fornasiere, A. Perillo-Marcone, C. Torregrosa
CERN, Geneva, Switzerland
A.M. Casella, D.J. Senor
PNNL, Richland, Washington, USA
C.J. Densham
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
T. Ishida, S. Makimura
KEK, Ibaraki, Japan
V.I. Kuksenko, S.G. Roberts
University of Oxford, Oxford, United Kingdom
Y. Lee, T.J. Shea, C.A. Thomas
ESS, Lund, Sweden
L.F. Mausner, D. Medvedev, N. Simos
BNL, Upton, Long Island, New York, USA
E. Wakai
KEK/JAEA, Ibaraki-Ken, Japan

Funding: Work supported by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The RaDIATE collaboration (Radiation Damage In Accelerator Target Environments) was founded in 2012 to bring together the high-energy accelerator target and nuclear materials communities to address the challenging issue of radiation damage effects in beam-intercepting materials. Success of current and future high intensity accelerator target facilities requires a fundamental understanding of these effects including measurement of materials property data. Toward this goal, the RaDIATE collaboration organized and carried out a materials irradiation run at the Brookhaven Linac Isotope Producer facility (BLIP). The experiment utilized a 181 MeV proton beam to irradiate several capsules, each containing many candidate material samples for various accelerator components. Materials included various grades/alloys of beryllium, graphite, silicon, iridium, titanium, TZM, CuCrZr, and aluminum. Attainable peak damage from an 8-week irradiation run ranges from 0.03 DPA (Be) to 7 DPA (Ir). Helium production is expected to range from 5 appm/DPA (Ir) to 3,000 appm/DPA (Be). The motivation, experimental parameters, as well as the post-irradiation examination plans of this experiment are described.

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THOAA2

Research on Compensation of Superconducting Cavity Failures in C-ADS Injector-I

FPGA, hardware, cavity, space-charge

3635

J.P. Dai, C. Meng, Y. Shao, Z. Xue, F. Yan
IHEP, Beijing, People's Republic of China

Funding: Work supported by Natural Science Foundation of China (11575216)
For the proton accelerators such as the China Accelerator Driven subcritical System(C-ADS), it is essential and difficult to achieve extremely high performance reliability requirement. In order to achieve this performance reliability requirement, in addition to hardware improvement, a failure tolerant design is mandatory. A compensation mechanism to cope with hardware failure, mainly RF failures of superconducting cavities, will be in place in order to maintain the high uptime, short recovery time and extremely low frequency of beam loss. This paper proposes an innovative and challenging way for compensation and rematch of cavity failure with the hardware implementation of the scheme using fast electronic devices and Field Programmable Gate Arrays (FPGAs). A method combined building an equivalent model for the FPGA with an improved genetic algorithm has been developed. Results based on the model and algorithm are compared with TRACEWIN simulation to show the precision and correctness of the mechanism.

Slides THOAA2 [2.414 MB]

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THOAA3

Installation and First Commissioning of the LLRF System for the European XFEL

LLRF, cavity, operation, cryomodule

3638

J. Branlard, G. Ayvazyan, V. Ayvazyan, L. Butkowski, M. Fenner, M.K. Grecki, M. Hierholzer, M. Hoffmann, M. Killenberg, D. Kostin, D. Kühn, F. Ludwig, D.R. Makowski, U. Mavrič, M. Omet, S. Pfeiffer, H. Pryschelski, K.P. Przygoda, A.T. Rosner, R. Rybaniec, H. Schlarb, Ch. Schmidt, N. Shehzad, B. Szczepanski, G. Varghese, H.C. Weddig, R. Wedel, M. Wiencek, B.Y. Yang
DESY, Hamburg, Germany
W. Cichalewski, F. Makowski, A. Mielczarek, P. Perek
TUL-DMCS, Łódź, Poland
K. Czuba, P.K. Jatczak, T.P. Leśniak, K. Oliwa, D. Sikora, M. Urbański, W. Wierba
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
A.S. Nawaz
TUHH, Hamburg, Germany

The installation phase of the European X-ray free laser electron laser (XFEL) is finished, leaving place for its commissioning phase. This contribution summarizes the low-level radio frequency (LLRF) installation steps, illustrated with examples of its challenges and how they were addressed. The commissioning phase is also presented, with a special emphasis on the effort placed into developing LLRF automation tools to support the commissioning of such a large scale accelerator. The first results of the LLRF commissioning of the XFEL injector and first RF stations in the main linac are also given.

Slides THOAA3 [15.800 MB]

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THYA1

New Scenarios of Microbunching Instability Control in Electron Linacs and Free Electron Lasers

FEL, electron, laser, controls

3642

E. Roussel, E. Allaria, M.B. Danailov, S. Di Mitri, E. Ferrari, D. Gauthier, L. Giannessi, G. Penco, M. Veronese
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

Laser-heater systems are essential tools to control and optimize high-gain free-electron lasers (FELs) working in the x-ray wavelength range. Indeed, these systems induce a controllable increase of the energy spread of the electron bunch. The heating suppresses longitudinal microbunching instability which otherwise would limit the FEL performance. We demonstrate that, through the action of the microbunching instability, a long-wavelength modulation of the electron beam induced by the laser heater at low energy can persist until the beam entrance into the undulators. This coherent longitudinal modulation is exploited to control the FEL spectral properties, in particular, multicolor extreme-ultraviolet FEL pulses can be generated through a frequency mixing of the modulations produced by the laser heater and the seed laser in the electron beam. We present an experimental demonstration of this novel configuration carried out at the FERMI FEL.
*E. Roussel et al., Phys. Rev. Lett. 115, 214801 (2015)

Slides THYA1 [14.837 MB]

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THOBA3

A Compact 335 MeV Positron Damping Ring Design for FACET-II

positron, damping, emittance, quadrupole

3652

G.R. White, Y. Cai, R.O. Hettel, M.A.G. Johansson, V. Yakimenko, G. Yocky
SLAC, Menlo Park, California, USA

Funding: This work was supported by the Department of Energy under Contract Number: DE-AC02-76SF00515.
FACET-II will be a new test facility, starting construction in 2018 within the main SLAC Linac. Its purpose is to build on the decades-long experience developed conducting accelerator R&D at SLAC in the areas of advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. The positron system design utilizes an existing W-Re target in Linac Sector 19, driven by 4 nC electrons bunches at 10 GeV. We present the design of a 335 MeV, 21.4 m circumference damping ring required to damp emittance from a modified positron return beamline by a factor of 500. The transverse emittance is calculated to be 6 um-rad, fully coupled, with a bunch length of 4 mm and energy spread 0.06 %, at a bunch charge of 1 nC. The arc magnets need to be especially compact due to tight space constraints (installation will be in the existing SLAC Linac tunnel, Sector 10, with 3 m width available) and were a key design challenge. We present a solution with combined function bend/quadrupole/sextupole magnets which have been modelled in 3D using Opera.

Slides THOBA3 [8.372 MB]

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THOBB3

ESS SRF Linear Accelerator Components Preliminary Results and Integration

cavity, SRF, cryomodule, accelerating-gradient

3666

C. Darve, N. Elias, C.G. Maiano, F. Schlander
ESS, Lund, Sweden
C. Arcambal, G. Devanz, F. Peauger
CEA/DRF/IRFU, Gif-sur-Yvette, France
E. Cenni
CEA/IRFU, Gif-sur-Yvette, France
G. Costanza
Lund University, Lund, Sweden
P. Duthil, G. Olry, D. Reynet
IPN, Orsay, France
L. Hermansson
Uppsala University, Uppsala, Sweden
P. Michelato, D. Sertore
INFN/LASA, Segrate (MI), Italy

The European Spallation Source (ESS) is a pan-European project and one of world's largest research infrastructures based on neutron sources. This collaborative project is funded by a collaboration of 17 European countries and is under construction in Lund, Sweden. The 5 MW, 2.86 ms long pulse proton accelerator has a repetition frequency of 14 Hz (4 % duty cycle), and a beam current of 62.5 mA. The Superconducting Radio-Frequency (SRF) linac is composed of three families of Superconducting Radio-Frequency (SRF) cavities, which are being prototyped, counting the spoke resonators with a geometric beta of 0.5, medium-beta elliptical cavities (beta_g=0.67) and high-beta elliptical cavities (beta_g=0.86). After a description of the ESS linear accelerator layout, this article will focus on the recent progress towards integration of the first test results of the main critical components to be assembled in cryomodules, then in the ESS tunnel.

Slides THOBB3 [25.611 MB]

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THPAB001

Microbunching Instability as a Caustic Phenomenon

electron, radiation, bunching, synchrotron

3676

T.K. Charles, D.M. Paganin
Monash University, Faculty of Science, Clayton, Victoria, Australia
M.J. Boland
The University of Melbourne, Melbourne, Victoria, Australia
M.J. Boland, R.T. Dowd
SLSA, Clayton, Australia

Microbunching instability if left alone, threatens to degrade the beam quality of high brightness electron beams in Free Electron Lasers. Recently, caustic formation in electron trajectories was identified as a mechanism describing current modulations in accelerated particle beams. Here we consider CSR-induced microbunching as a caustic phenomenon. This analysis reports on the influence of longitudinal dispersion, R56, on the microbunching process, as well as elucidating the influence of the second and third order longitudinal dispersion values, T566 and U5666.

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THPAB012

Beam Transport Optimization for Applying an SRF Gun at the ELBE Center

electron, gun, SRF, radiation

3712

P.N. Lu, A. Arnold, P. Murcek, J. Teichert, H. Vennekate, R. Xiang
HZDR, Dresden, Germany

An SRF gun at the ELBE center has been operated with a magnesium cathode. Electron beams were produced with a maximum bunch charge of 200 pC and an emit-tance of 7.7 μm. Simulations have been conducted with ASTRA and Elegant for applying the SRF gun to ELBE user experiments, including neutron beam generation, positron beam generation, THz radiation and Compton backscattering experiment. Beam transport has been optimized to solve the best beam performance for these user stations at the bunch charge of 200 pC. Simulation results indicate that the SRF gun is potential to benefit the high bunch charge applications at ELBE.

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THPAB016

Investigation on the Ion Motion Towards Clearing Electrodes in an Accelerator

ion, electron, simulation, software

3723

G. Pöplau
COMPAEC e.G., Rostock, Germany
A. Meseck
HZB, Berlin, Germany

High brightness beams provided by linac-based accelerators require several measures to preserve their high quality and to avoid instabilities, where the mitigation of the impact of residual ions is one of these measures, in particular if high repetition rates are aimed for. Over the last decade three ion-clearing strategies: clearing electrodes, bunch gaps and beam shaking have been applied to counteract the degrading impact of the ions on the electron beam. Currently, their merit as clearing strategies for next generation high brightness accelerators such as energy recovery linacs (ERLs) are under intensive investigations with both simulations and measurements. In this paper, we present numerical studies for the behavior of ions generated by electron bunch passages within the field of electrodes. The objective is to investigate the ion motion towards the electrodes and to study under which circumstances and up to which ratio, equilibrium between ion generation and ion-clearing is established. Hereby several ion species and shapes of electrodes are considered with typical parameters of future high current linacs.

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THPAB019

PSPA, a Web Platform for Simulation of Particle Accelerator

simulation, lattice, interface, positron

3730

M.E. Biagini, A. Variola
INFN/LNF, Frascati (Roma), Italy
L. Garnier, H. Guler, C. Helft, G. Le Meur, M. Nicolas, A. Pérus, F. Touze
LAL, Orsay, France

PSPA (Platform for Simulation of Particle Accelerators) is an original web-based interactive simulation platform for designing and modelling particle accelerators created at Laboratoire de l'Accélérateur Linéaire, Orsay. It aims at eventually containing all the tools to make a start-to-end simulation of an accelerator, and make it possible to run interactively several open source simulations codes available worldwide. At the moment, the focus is on electron/positron accelerators. PSPA will optimize the work of accelerator designers by factoring once and for all the tedious, time-consuming and error prone process of translating data formats between the various codes involved in the modelling of a machine, controlling the repeated execution of these models by easily varying some parameter and managing the associated data. Moreover, as a truly innovative feature, it will provide a convenient means for testing different physical models of a given part of a machine. The status of the project is described in this paper, and examples of its application to the ThomX compact Compton backscattering source at LAL are presented.

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THPAB031

Study of Beam Break Up in Irradiation Linacs

wakefield, electron, experiment, simulation

3767

X.C. Meng, H.B. Chen, W. Gai, J. Shi, S.X. Zheng
TUB, Beijing, People's Republic of China
G.H. Li, J.S. Liu, Y.H. Liu
NUCTECH, Beijing, People's Republic of China
F.H. de Sá
LNLS, Campinas, Brazil

Many recent experiments of the irradiation linacs produced at Tsinghua University indicate that beam power is limited by beam break up (BBU). Limits exist while the beam current or the pulse width is increased. In this paper, we illustrate the bream break up (BBU) phenomenon in the cases of both the 10MeV travelling-wave linac and 10MeV backward travelling-wave linac. The higher order modes in the linacs are analysed and the wake fields are calculated both with theoretical analysis and numerical simulation. Also, the beam dynamics is studied on the basis of the wakefield results to find a BBU threshold in these structures.

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THPAB038

DYNAC: Extensions, Updates, and Upgrades

simulation, lattice, operation, quadrupole

3784

S. Molloy, E. Tanke
ESS, Lund, Sweden

DYNAC is a multi-particle beamline simulation code suitable for modelling of the motion of protons, heavy ions, or electrons, moving through linear accelerators and beam transport lines. In this paper, we document extensions written in Python. It will be shown how these Python extensions add a considerable amount of flexibility to DYNAC, while maintaining the calculation speeds available from the core Fortran source. Real-world use-cases are discussed. In addition, some improvements that have been made to the DYNAC source are reported.

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THPAB039

Novel Manufacturing Concepts for 12 GHz High Gradient Accelerating Structures

vacuum, operation, alignment, damping

3787

A. Solodko, S. Atieh, N. Catalán Lasheras, A. Grudiev, S. Lebet, W. Wuensch
CERN, Geneva, Switzerland
H. Zha
TUB, Beijing, People's Republic of China

CLIC high gradient accelerating structures (AS) work-ing in X-band are made of copper ultra-high precision discs, requiring both milling and turning operations. Discs are then joint together by diffusion bonding. The rest of important technical systems, such as vacuum, cooling and manifolds, to house damping silicon carbide absorbers, are brazed to the bonded disc stack afterwards. This manufacturing technique has been successfully demonstrated but it is very challenging and needs an accurate assembly at every production step. Main issues concern vacuum-tightness, misalignment, deformations during different assembly operations, defects of braz-ing/bonding operations (gaps, a leak of brazing material) etc. Preparation and repairs are time and resource con-suming and increase the final price of the accelerating structure. This paper describes the novel manufacturing concepts for 12 GHz high gradient AS and focuses on new joining techniques as electron beam welding or brazing, new engineering solutions, as rectangular cells or structures made of halves are being considered.

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THPAB059

CSR and Space Charge Studies for the CLARA Phase 1 Beamline

dipole, electron, simulation, space-charge

3851

B.S. Kyle, R.B. Appleby
UMAN, Manchester, United Kingdom
J.K. Jones, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
M.J. de Loos, S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

The installation of Phase 1 of CLARA, the UK's new FEL test facility, is currently underway at Daresbury Laboratory. When completed, it will be able to deliver 45 MeV electron beams to the pre-existing VELA beamline, which runs parallel. Phase 1 consists of a 10 Hz photocathode gun, a 2 m long S-band travelling wave linac, a spectrometer line, and associated optics and diagnostics. A detailed study into the beam dynamics of the lattice is presented, with a focus towards the effects of space charge and coherent synchrotron radiation on the electron bunch. Simulations disagreed with predictions from a one-dimensional model of coherent radiation, and this disagreement is believed to be due to a violation of the Derbenev criterion.

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THPAB072

Application of Voronoi Diagram to Mask-Based Intercepting Phase-Space Measurements

emittance, electron, experiment, laser

3872

A. Halavanau, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
Q. Gao, J.G. Power, E.E. Wisniewski
ANL, Argonne, Illinois, USA
Q. Gao
TUB, Beijing, People's Republic of China
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
P. Piot
Fermilab, Batavia, Illinois, USA

Intercepting multi-aperture masks (e.g. pepper pot or multislit mask) combined with a downstream transverse-density diagnostics (e.g. based on optical transition radiation or employing scintillating media) are commonly used for characterizing the phase space of charged particle beams and the associated emittances. The required data analysis relies on precise calculation of the RMS sizes and positions of the beamlets originated from the mask which drifted up to the analyzing diagnostics. Voronoi diagram is an efficient method for splitting a plane into subsets according to the distances between given vortices. The application of the method to analyze data from pepper pot and multislit mask based measurement is validated via numerical simulation and applied to experimental data acquired at the Argonne Wakefield Accelerator facility. We also discuss the application of the Voronoi diagrams to quantify transversely-modulated beams distortion.

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THPAB099

Challenges of a Stable ERL Operation Concerning the Digital RF Control System of the S-DALINAC

controls, operation, HOM, beam-loading

3951

M. Steinhorst, M. Arnold, U. Bonnes, C. Burandt, N. Pietralla
TU Darmstadt, Darmstadt, Germany
T. Kürzeder
HIM, Mainz, Germany

Funding: Supported by the DFG through RTG 2128.
The superconducting recirculating electron linear accelerator S-DALINAC is the central large-scale research device of the institute for nuclear physics at the TU Darmstadt in Germany. In 2015/2016 the S-DALINAC received an upgrade to three recirculations. The new beam line enables in addition to higher maximum energies the possibility to operate the S-DALINAC as an Energy Recovery Linac (ERL). Therefore the current rf control system encounters new requirements for ERL operation. Since 2010 a digital rf control system is successfully used for the control of the superconducting cavities. This system was not built and optimized for the control of an ERL. This contribution is discussing the expected challenges of an ERL operation regarding the existing digital rf control system.

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THPAB113

Time Synchronization for Distant IOCs of the SuperKEKB Accelerators

timing, EPICS, operation, network

3982

H. Kaji, T. Naito, S. Sasaki
KEK, Ibaraki, Japan
Y. Iitsuka
EJIT, Hitachi, Ibaraki, Japan

The time synchronization for multi CPU system is always a problem to be worried. The control system of accelerator is no exception since it consists of a lot of CPUs located among large area distantly. The problem appears conspicuously when the beam is aborted. Usually, several hardware show abort signals in one beam abort event. However it is difficult to know which is the source of beam abort and which issues an abort signal under the influence of original failure. We introduce the time synchronization system of the SuperKEKB collider which choose EPICS as the control software. The system utilize Event Timing System and synchronizes the EPICS general time for I/O controllers located distantly. The accuracy of synchronization is around 10ns. It is the excellent performance in terms of synchronization of CPU time. The all abort channels of SuperKEKB are synchronized their issued time. Besides they synchronize with also the injector linac which is operated with the different control system in different network.

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THPAB118

Stabilization of Timing System Operation of J-PARC Linac and RCS

timing, operation, network, software

4000

H. Takahashi, N. Hayashi
JAEA/J-PARC, Tokai-mura, Japan
Y.I. Itoh
Total Support Systems Corporation, Tokai-mura, Naka-gun, Ibaraki, Japan
M. Kawase, Y. Sawabe
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

At the timing system for J-PARC Linac and Rapid Cycling Synchrotron (RCS), the distribution of timing information (beam tag, type, etc.) and the monitoring and control of timing system are performed via the reflective memory (RFM). The more 10 years elapsed after operation start of J-PARC. Therefore, it is concerned about the occurrence of malfunctions due to time-related deterioration of the devices of timing system. Especially, the malfunctions of a management computer to monitor and control the all timing devices and RFMs to configure the timing system data network have a significant impact. Then, the management computer was renewed and PCI-Express RFMs are installed instead of PCI RFMs. However, after renewal computer, the trouble by data corruption of RFM network was happened anew. In this paper, the contents and the results our cause investigation of data corruption and those of the measures employed for stabilizing the timing system operation are presented.

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THPAB127

Development of 1.3 GHz Cavity Combiner for 24 kW CW SSA

cavity, coupling, simulation, electromagnetic-fields

4020

W. Liu, B. Du, G. Huang, L. Lin, L. Shang, W.B. Song
USTC/NSRL, Hefei, Anhui, People's Republic of China

The 24KW CW SSA (Solid-State Amplifier) is being developed to drive the 1.3GHz SC Linac used in a THz light source. The SSA adopts the compact all-in-one combining method ' cavity combiner, which is proposed and developed in recent years. This paper reports the R&D of the cavity combiner. The cavity combiner resonates in TM010 mode, coupling with 24 coaxial-connected 1kW amplifier modules. The cavity's electromagnetic characteristic is calculated by CST, and the mechanical structure including the input and output coupler has been designed.

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THPAB140

MAX IV Online Linac Model

TANGO, GUI, simulation, controls

4047

L. Isaksson, E. Mansten, S. Thorin
MAX IV Laboratory, Lund University, Lund, Sweden

An online linac model has been developed at MAX IV in order to enable a calculation of the properties of the linac beam based on the actual settings of the magnetic elements. The model is based on the Elegant simulation code and uses the design linac lattice file. A set of Matlab scripts fetch the actual settings of all elements via the Tango control system, pass these values on to Elegant and run the simulation. The model includes an optimization option for yielding desired beta- and alpha-function values at various points along the linac by calculating optimal settings for chosen elements.

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THPAB155

Photoinjector Optimization Using a Derivative-Free, Model-Based Trust-Region Algorithm for the Argonne Wakefield Accelerator

gun, emittance, laser, simulation

4100

N.R. Neveu
IIT, Chicago, Illinois, USA
J.M. Larson, J.G. Power
ANL, Argonne, Illinois, USA
L.K. Spentzouris
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: DE-SC0015479, DE-AC02-06CH11357, DE-AC02-06CH11357
Model-based, trust-region, derivative-free algorithms are increasingly popular for optimizing computationally expensive numerical simulations. A strength of such methods is their efficient use of function evaluations. In this paper, we use one such algorithm to optimize the beam dynamics in two cases of interest at the Argonne Wakefield Accelerator (AWA) facility. First, we minimize the emittance of the electron bunch produced by the AWA drive rf photocathode gun alone by adjusting three parameters: rf gun phase, solenoid strength, and laser radius. The algorithm used converges to a set of parameters with an emittance of 1.08 mm-mrad. Second, we expand the number of optimization parameters to model the complete AWA rf photoinjector linac (the gun and six accelerating cavities). These results are used in a Pareto study of the trade-off between beam emittance and bunch length for the AWA linac.

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THPIK002

Development of a Range of High Peak Power Solid-State Amplifiers for Use in the Heavy Ion Linac at JINR, Dubna

cavity, ion, heavy-ion, impedance

4108

S.C. Dillon, J.L. Reid
Tomco Technologies, Stepney, South Australia, Australia
A.V. Butenko
JINR, Dubna, Moscow Region, Russia
H. Höltermann, H. Podlech, U. Ratzinger
BEVATECH, Frankfurt, Germany

A range of LDMOS based amplifiers rated for up to 340kW peak power and operating at 100.625MHz were developed for use as RF sources for driving cavities in the heavy ion LINAC (HILac) at JINR, Dubna. The final solution had to be compact and competitive while addressing technical challenges such as phase and amplitude stability, long term reliability, reflected power handling and serviceability. Design considerations and performance results are presented.

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THPIK017

Field Uniformity Preservation Strategies for the ESS DTL: Approach and Simulations

DTL, simulation, drift-tube-linac, coupling

4139

G.S. Mauro, F. Grespan, A. Palmieri, A. Pisent
INFN/LNL, Legnaro (PD), Italy
P. Mereu, M. Mezzano, C. Mingioni, M. Nenni
INFN-Torino, Torino, Italy

The Drift Tube Linac (DTL) of the European Spallation Source (ESS) is designed to operate at 352.2 MHz with a duty cycle of 4 % (3 ms pulse length, 14 Hz repetition period) and will accelerate a proton beam of 62.5 mA pulse peak current from 3.62 to 90 MeV. This paper presents the approach taken in order to preserve field flatness of DTL Tanks. This strategy required a set of simulations and consequent choices about RF design of DTL cells, RF coupler tuning and compensation, cooling of the DTL cells. Outcomes of these simulations and the experimental verifications of this approach are then explained.

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THPIK021

Structural Mechanical Analysis of 4-Rod RFQ Structures in View of a Newly Revised CW RFQ for the HLI at GSI

rfq, quadrupole, simulation, resonance

4142

D. Koser, H. Podlech
IAP, Frankfurt am Main, Germany
P. Gerhard, L. Groening
GSI, Darmstadt, Germany
O.K. Kester
TRIUMF, Vancouver, Canada

Funding: BMBF Contr. No. 05P15RFRBA
The High Charge State Injector (HLI) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, serves as one of the two injector linacs for the UNILAC as well as dedicated injector for the upcoming cw linac project for super heavy element research. As the front end of the HLI is planned to be upgraded for cw operation a newly revised cw capable RFQ structure with an operating frequency of 10⁸ MHz is required. The existent 4-rod structure, which was commissioned at the HLI in 2010, suffers from severe modulated rf power reflections originating from mechanical oscillations of the electrodes that both limit the achievable performance and impede stable operation*. Besides preceding vibration measurements that were done by GSI using a laser vibrometer**, the structural mechanical behavior of the 4-rod geometry was extensively analyzed using ANSYS Workbench. Thereby the crucial mechanical eigenmodes could be identified and their impact on the rf properties was investigated by simulations using CST MWS. A completely newly revised 4-rod RFQ design with optimized structural rigidity was developed of which a 6-stem prototype is currently being manufactured.
*P. Gerhard et al., Experience With a 4-Rod CW Radio Frequency Quadrupole, LINAC12, THPLB07
**P. Gerhard et al., In Situ Measurements of Mechanical Vibrations of a 4-Rod RFQ at GSI, LINAC14, TUPP057

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THPIK023

Concept of the High Power RF Systems for MESA

cavity, experiment, SRF, LLRF

4147

R.G. Heine, F. Fichtner
IKP, Mainz, Germany

Funding: work supported by DFG under the cluster od Excellence PRISMA, EXC 1098/2014
The Mainz Energy-recovering Superconducting Accelerator (MESA) is currently designed and built at the Institut für Kernphysik (KPH) at Johannes Gutenberg-Universität Mainz. The main accelerator incorporates four superconducting cavities of the TESLA type, while the preaccelerator MAMBO (Milliampere Booster) is a room temperature linac. The MESA high power RF-systems have to cover a vast power range starting at some 10kW per cavity for the main linac modules and more 50kW per cavity for MAMBO. In this paper we will present the concept of a unified high power RF system for both main accelerator and preaccelertor, based on solid state technology.

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THPIK027

Dynamic Behaviour of Fast-Pulsed Quadrupole Magnets for LINAC4 Transfer Line

quadrupole, flattop, target, sextupole

4150

S. Kasaei
IPM, Tehran, Iran
M.C.L. Buzio, L. Fiscarelli
CERN, Geneva, Switzerland

Linac4, recently built at CERN, is a linear normal conducting accelerator for negative hydrogen ions (H⁻). A new transfer line will link Linac4 to the Proton Synchrotron Booster. This transfer line includes 21 quadrupole magnets characterized by fast excitation cycles, which make accurate magnetic measurements challenging. This paper describes the method used for the measurement, which is a combination of techniques based on rotating and fixed search coils. We show how these instruments can be used in a complementary way to derive information on different aspects of the magnetic behaviour of these quadrupoles, such as the impact of hysteresis and dynamic eddy current effects.

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THPIK032

Installation and Low Power Test of IFMIF-EVEDA RFQ at Rokkasho Site

rfq, cavity, vacuum, dipole

4162

E. Fagotti, L. Antoniazzi, A. Baldo, A. Battistello, L. Bellan, P. Bottin, M. Comunian, A. Conte, L. Ferrari, M.G. Giacchini, F. Grespan, M. Montis, A. Palmieri, A. Pisent, D. Scarpa
INFN/LNL, Legnaro (PD), Italy
D. Agguiaro, A.G. Colombo
INFN- Sez. di Padova, Padova, Italy
F. Borotto Dalla Vecchia, G. Dughera, G. Giraudo, P. Mereu, R. Panero
INFN-Torino, Torino, Italy
P. Cara, R. Heidinger
Fusion for Energy, Garching, Germany
M. Furini, C. Gessi
INFN-Bologna, Bologna, Italy
D. Gex
F4E, Germany
R. Ichimiya, Y. Ikeda, A. Kasugai, K. Kondo, S. O'hira, K. Sakamoto, T. Shinya, M. Sugimoto
QST, Aomori, Japan
J. Knaster, A. Marqueta, G. Pruneri, F. Scantamburlo
IFMIF/EVEDA, Rokkasho, Japan

The IFMIF-EVEDA RFQ is composed of 18 modules for a total length of 9.8 m and is designed to accelerate the 125 mA D⁺ beam up to 5 MeV at the frequency of 175 MHz. The RFQ is subdivided into three Super-Modules of six modules each. The Super-Modules were shipped to Rokkasho (Japan) at the beginning of 2016, pre-assembled 3 m far from the final location and tuned to reach target field flatness requirements. Just after conclusion of injector commissioning, the tuned RFQ was disassembled, moved and reassembled in the final location. After confirmation that field flatness was not affected by this movement, high power couplers were installed and tuned and all the structure was baked. Assembling, tuning and coupling results will be presented.

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THPIK035

Rf Properties of a 175 MHz High-Q Load Circuit

rfq, operation, coupling, vacuum

4169

S. Maebara, M. Sugimoto
QST, Aomori, Japan

For an RF input coupler test, a 175MHz high-Q load circuit based on a 6 1/8 in. co-axial waveguide was developed. This circuit consists of the RF input coupler, a trombone-type phase shifter and a stub tuner. The coupler with a loop antenna and the stub tuner are located in edges of the circuit, the loop antenna and the tuner work for a short plate. When RF input power is injected into the circuit, a high-voltage standing wave is excited by adjusting the tuner. The power of standing wave required for the tests is also accumulated due to its low resistive loss. At the operation frequency of 175 MHz, the resistive loss of 0.046ohm is measured and an equivalent RF power of 200 kW is accumulated by the RF input power of 740 W. In this circuit, the bandwidth is narrow to be ±5 kHz in S11 parameter of less -20 dB, but the equivalent RF power of 200 kW-14 sec CW could be achieved after sufficient RF aging. Using this high-Q load circuit, all the fabricated 9 couplers were successfully tested for RF contact defects, unnecessary low-Q value and extraordinary outgassing. This article describes these RF properties in detail.

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THPIK039

Multipactor Problem of J-PARC SDTL

multipactoring, cavity, simulation, operation

4184

T. Ito, T. Morishita, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan
K. Nanmo, T. Sugimura
KEK, Ibaraki, Japan

We have suffered from multipactor problem of some SDTL after the Great East Japan Earthquake. As a designed operating rf power of the SDTL is in the multipactor region, we had to operate at higher power of the designed one. From the result of the simulation and the observation of the SDTL cavity, it became clear that the multipactor occurred on the inner surface of the cavity. We think that one of the cause of the maultipactor is the contamination on the inner surface of the cavity, we performed the cleaning of the inner surface of the cavity by using acetone. The cleaning was very effective and the multipactor region was reduced dramatically or disappeared. The multipactor problem has not occurred since then.

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THPIK043

Design and Optimization of a 2MeV X-Band Side Coupled Accelerating Structure

coupling, impedance, simulation, beam-loading

4193

H. Yuan
IHEP, Beijing, People's Republic of China

An X-band bi-period side-coupled accelerating structure has been designed in this paper. The structure's working frequency is 9.3GHz. '/2 mode is chosen for the structure's stability. There are 11 accelerating cells, the first 5 work as non-light velocity part while the other 6 work as light velocity part. After CST simulation, the coupling constant between accelerating cells and coupling cells is 5%, efficient shunt impedance is 142M'/m. For the beam dynamic analysis, the particle energy is selected to be 2 MeV and the peak current is 60 mA for the radiation dosage limits by national standard. After Pamela optimization, the particle's capture efficiency is more than 30%. To feed power into the structure, a coupler is designed in the middle of the structure and the coupling coefficient is 1.4. The structure is manufactured and the measurement result accords well with designing value.

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THPIK045

Design of a C-band Travelling-wave Accelerating Structure at IHEP

cavity, impedance, simulation, wakefield

4196

J.R. Zhang, Y.L. Chi, J. Lei, H. Wang, X. Wang
IHEP, Beijing, People's Republic of China
S. Shu
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

A C-band travelling wave accelerating structure has been developed at IHEP. The structure is a constant gra-dient type and operating with a 3'/4 mode. The total length of the structure is 1.8-meters long with 85 regular cells and two coupler cells. 2D program Superfish is used to optimize the cavity shape and the iris size. The wall cells are rounded for it can improved the Q value for about 10%. The cell irises have an elliptical profile to minimize the peak surface electric fields. In order to compatible with the compact of the short-range wake field on the beam dynamics, the average iris radius is 7.15 mm. The group velocity of the designed structure is from 2.8% to 1.4%. Between the rectangular waveguide and the accelerating structure, magnetic coupling is adopted. The coupled cavity is racetrack type in order to minimize the asymmetry in the coupler. Kyhl's method is used to match the input and output coupler.

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THPIK049

High Power Conditioning of the DTL-1 for CSNS

DTL, cavity, vacuum, ion

4207

H.C. Liu, Q. Chen, K.Y. Gong
IHEP, Beijing, People's Republic of China
M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, Y. Wang, X.L. Wu
CSNS, Guangdong Province, People's Republic of China

The RF tuning of the first DTL tank for the China spalla-tion neutron source was finished leading to a stabilized-uniform accelerating field. After the installation of the DTL-1 in the linac tunnel, the high power conditioning was carried out deliberately. Consequently a peak RF power of 1.6MW with 25Hz repetition rate and 650'sec pulse width was put into the tank stably. A 3MeV H⁻ ion was injected into the DTL-1 and was successfully accel-erated to 21.6MeV with almost 100% transmission. Dur-ing the operation, The DTL-1 tank worked stable in the design power level. The conditioning details will be pre-sented in this paper.

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THPIK057

Development of a High-Power X-Band RF Rotary Joint

simulation, network, insertion, scattering

4224

J. Liu, H.B. Chen, J. Shi, X.W. Wu, H. Zha
TUB, Beijing, People's Republic of China

RF rotary joints allow the independent movement be-tween the RF power source and the accelerating tube of a linear accelerator (linac). In this paper, the design of a compact X-band (9.3 GHz) high-power RF rotary joint is presented. Simulation results illustrate that RF parameters (the scattering matrix) of this rotary joint keep stable in the arbitrary rotation angle. The maximum return loss is about -30 dB, the insert loss is less than 0.11 dB, and the variance of output phase shifts is below 1 degree while rotating the joint. RF measurement on the rotary joint using Vector-Network analyser is also conducted and presented in this paper.

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THPIK058

Development of a S-Band Pulse Compressor

cavity, klystron, coupling, laser

4227

P. Wang, H.B. Chen, C. Cheng, J. Shi, X.W. Wu, H. Zha
TUB, Beijing, People's Republic of China

We designed and fabricated a pulse compressor for S-band high power test stand at Tsinghua University. This pulse compressor is made up of a sphere resonant cavity with quality factor of 100000 and a rf polarizer. It has the ability of compressing a pulse from 3.6 us to 300 ns with the power gain of 7. A short description of the pulse compressor is presented, together with the RF design and low level RF measurement.

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THPIK067

A C-Band Compact Spherical RF Pulse Compressor for the SXFEL Linac Energy Upgrade

cavity, coupling, electron, simulation

4248

Z.B. Li, W. Fang, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

A new compact C-band (5712 MHz) spherical RF pulse compressor has been designed for Shanghai Soft X-ray Free Electron Laser (SXFEL) facility energy upgrading at Shanghai Institute of Applied Physics (SINAP), Chinese Academy of Sciences (CAS). This pulse compressor contains one high Q0 spherical RF resonant cavity which works on two TE113 modes and a novel coupler. As there is only one storage cavity, this pulse compressor can be much smaller than the traditional SLED. With the coupling coefficient 4.9, the average power gain can be as high as 3.8. In this paper, the scheme of the C-band spherical pulse compressor and RF design are presented.

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THPIK070

Localization of RF Breakdown Point in a Coaxially Loaded LINAC Cavity

cavity, electron, operation, accelerating-gradient

4254

Q.S. Chen, T. Hu, B. Qin
HUST, Wuhan, People's Republic of China
Y.J. Pei
USTC/NSRL, Hefei, Anhui, People's Republic of China

Here we report how the RF breakdown point (RFBP) can be localized in a coaxially loaded linac cavity with just the forward and the reflected power signal. The cavity uses 4 load cells instead of output coupler to absorb remanent power, so no transmitted power signal could be recorded. We propose two methods to analyze the measured signals and localize the RFBP. One method focuses on the time delay of the two signals while the other one focuses on the amplitude. Quantitative analysis showed the two methods were well consistent with each other and indicated the RFBP located at the end of the linac cavity.

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THPIK081

Design and Construction of a High-Gradient RF Lab at IFIC-Valencia

klystron, vacuum, diagnostics, network

4272

A. Vnuchenko, T. Argyropoulos, C. Blanch Gutiérrez, D. Esperante Pereira, A. Faus-Golfe, J. Giner Navarro
IFIC, Valencia, Spain
N. Catalán Lasheras, G. McMonagle, I. Syratchev, W. Wuensch
CERN, Geneva, Switzerland
A. Faus-Golfe
LAL, Orsay, France

The IFIC High-Gradient (HG) Radio Frequency (RF) laboratory is designed to host a high-power infrastructure for testing HG S-band normal-conducting RF accelerating structures and has been under construction since 2016. The main objective of the facility is to develop HG S-band accelerating structures and to contribute to the study of HG phenomena. A particular focus is RF structures for medical hadron therapy applications. The design of the laboratory has been made through collaboration between the IFIC and the CLIC RF group at CERN. The layout is inspired by the scheme of the Xbox-3 test facility at CERN, and it has been adapted to S-band frequency. In this paper we describe the design and construction status of such a facility.

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THPIK082

Quadrupole Magnet Design for the ESS MEBT

quadrupole, dipole, operation, magnet-design

4276

D. Fernandez-Cañoto, I. Bustinduy, G. Harper, J.L. Muñoz, I. Rueda, S. Varnasseri
ESS Bilbao, Zamudio, Spain

Funding: Consortium ESS Bilbao
ESS Bilbao is responsible for the design and fabrication of the ESS MEBT as an In-Kind contribution. The MEBT includes a focusing lattice with 11 quadrupole magnets with different operational gradients, but fabricated from the same model to simplify manufacturing and save costs. The magnet is designed with a 20.5 mm aperture radius to generate focusing fields of up to 2.74 T and also includes two additional steering coil systems assembled around yoke return arms to produce vertical and horizontal dipole fields up to 20 G·m. The magnet model, which fabrication starts in 2017, is here introduced. Magnetic, thermoelectric and dimensional studies are performed and results compared to specifications. Suitable transfer functions for magnet operation and magnetic fields for a doublet system with a BCM magnetically shielded placed between the two magnets are presented.

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THPIK083

Mechanical Fabrication of ESS-Bilbao RFQ

rfq, vacuum, cavity, software

4279

J.L. Muñoz, I. Bustinduy, J. Martin, A. Ortega, I. Rueda, A. Zugazaga
ESS Bilbao, Zamudio, Spain
M.A. Carrera, A. Garbayo
AVS, Elgoibar, Spain

The fabrication of the first segment of ESS-Bilbao's RFQ has started in 2016. The segment, of about 800 mm in length, is an assembly of 4 elements: two major vanes and two minor ones. The assembly will be done by making use of carefully-designed vacuum polymeric gaskets instead of brazing. Electron beam welding has been used during fabrication of the vanes. Apart from conventional CAD systems, a home-made tool for vane modulation solid generation has been successfully used. Machining process from copper blocks to final elements is described in detail. Also, the software tools created to assess the quality of the vanes by analyzing the metrology measurements, particularly of the modulation, are described in the paper. In order to test and validate the chosen vacuum strategy, an aluminum model using the same gaskets as the final model was built and tested. Results will also be presented. The fabrication of the first segment is expected to end up in early 2017, so assembly, segment alignment and vacuum tests with the real device will also be included in the paper.

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THPIK084

Results from the 704 MHz Klystron and Multi-beam IOT Prototypes for the European Spallation Source

klystron, factory, operation, electron

4282

M. Jensen, C. Marrelli
ESS, Lund, Sweden

The European Spallation Source, currently under construction in Lund, Sweden, will contain 155 RF sources for proton beam acceleration. Of these, 120 are at 704 MHz. Each cavity will be powered by individual RF sources. The nominal beam pulse width is 2.86 ms and the RF systems are being specified for a pulse width up to 3.5 ms to allow for ramping and time for regulation. The repetition frequency is 14 Hz which results in 5% duty. The 704 MHz linac is divided into two sections, the medium beta and the high beta cavities. For schedule reasons, the medium beta linac, 36 RF sources, will be based on 1.5 MW pulsed power klystrons and the high beta section, 84 RF sources, is planned to be operated with 1.2 MW multi-beam IOTs. ESS ordered three klystron prototypes designed for the ESS parameters from different supplies and two multi-beam IOT technology demonstrators under two different contracts. We present the specifications for the amplifiers and the results of the klystron prototypes and report the result of the first 1.2 MW multi-beam IOT prototypes.

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THPIK088

A Compact 10 kW Solid-State RF Power Amplifier at 352 MHz

operation, impedance, insertion, network

4292

D.S. Dancila, A. Rydberg
Uppsala University, Department of Engineering Sciences, Uppsala, Sweden
A.E.T. Hjort, L. Hoang Duc, M.H. Holmberg, M. Jobs, R.J.M.Y. Ruber
Uppsala University, Uppsala, Sweden

A compact 10 kW RF power amplifier at 352 MHz was developed at FREIA for the European Spallation Source, ESS. The specifications of ESS for the conception of amplifiers are related to its pulsed operation: 3.5 ms pulse length and a duty cycle of 5\%. The realized amplifier is composed of eight kilowatt level modules, combined using a planar Gysel 8-way combiner. The combiner has a low insertion loss of only 0.2 dB, measured at 10 kW peak power. Each module is built around a commercially available LDMOS transistor in a single-ended architecture. During the final measurements, a total output peak power of 10.5 kW was measured.

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THPIK090

352 MHz Tetrode RF Stations for Superconducting Spoke Cavities

site, controls, power-supply, operation

4296

M. Jobs, K.J. Gajewski, V.A. Goryashko, H. Li, R.J.M.Y. Ruber, R. Wedberg
Uppsala University, Uppsala, Sweden

Two 352 MHz tetrode based RF stations for pulsed operation have been developed at the FREIA Laboratory, Uppsala University to validate the design and performance as RF source for the Spoke cavities in the first superconductive stage of the European Spallation Source(ESS) linear accelerator. The stations use dual TH595 tetrodes rated at 210 kW peak-power to provide a total power of 400 kW with a maximum pulse duration of 3.5 ms at 14 Hz repetition rate. Each tetrode is fed by a 10 kW solid state amplifier and the station is monitored by an internal control system with complete remote access. Extensive measurements have been performed on the RF performance, the power supplies as well as on the interlock systems. To conform to the specifications, special attention must be given for the response time of the tetrode power-supplies to acquire good quality RF output pulses. For the interlock system any shut-down condition due to tube malfunctioning or other sources must switch off the station in a controlled manner with minimal damage to any internal circuitry or to the tube itself whilst at the same time provide a fast discharge and cut-off of all relevant power supplies.

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THPIK094

Linac4 PIMS Construction and First Operation

cavity, vacuum, alignment, operation

4307

R. Wegner, G. Favre, P. Françon, J.-M. Geisser, F. Gerigk, J.-M. Giguet, J. Hansen, J.-B. Lallement, A.M. Lombardi, S. Papadopoulos, M. Polini, M. Redondas Monteserin, T. Tardy, N. Thaus, M. Vretenar
CERN, Geneva, Switzerland
W. Behr, M. Pap
Forschungszentrum Jülich GmbH, Central Institute of Engineering, Electronics and Analytics, Jülich, Germany
G. Brzezinski, P. Krawczyk, L. Kujawinski, M. Marczenko
NCBJ, Świerk/Otwock, Poland

Linac4, CERN's new H⁻ injector Linac uses PI-Mode Structures (PIMS) for the energy range between 10³ and 160 MeV. 180 copper elements for 12 PIMS cavities have been fabricated in a collaboration between CERN, NCBJ and FZJ from 2011 to 2016. The cavities have been assembled, RF tuned and validated at CERN. This paper reports on the results as well as the experience with construction, installation, RF conditioning and first operation with beam.

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THPIK097

High Power Tests of a Prototype X-Band Accelerating Structure for CLIC

vacuum, klystron, electron, collider

4318

R. Zennaro, H. Blumer, M. Bopp, T. Garvey, L. Rivkin
PSI, Villigen PSI, Switzerland
T. Argyropoulos, D. Esperante Pereira
IFIC, Valencia, Spain
N. Catalán Lasheras, A. Grudiev, G. McMonagle, A. Solodko, I. Syratchev, R. Wegner, B.J. Woolley, W. Wuensch
CERN, Geneva, Switzerland
T.G. Lucas, M. Volpi
The University of Melbourne, Melbourne, Victoria, Australia

Funding: Partially funded by SNF FLARE grant 20FL20₁47463
We present the design, construction and high-power test of an X-band radio-frequency accelerating structure, built as a prototype for the CERN LInear Collider (CLIC) study. X-band structures have been attracting increasing attention in recent years with applications foreseen in the domains of compact free electron lasers, medical accelerators and as diagnostics for ultra-short (femtosecond) electron bunches (when used in deflecting mode). To date, the main motivation for developments in this field has been as accelerating structures for linear colliders such as CLIC. In the context of a CERN/PSI collaboration we have built a prototype structure based on an existing CERN design, but with some modification, and following, as closely as possible, the realization and vacuum brazing techniques employed in the production of the C-band structures for the Swiss Free Electron Laser, SwissFEL. We will present the basic design of the structure and describe the fabrication process. The results of high power conditioning of the structure at CERN on an X-box test stand, to assess conditioning times, accelerating field and measure breakdown rates, will also be presented.

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THPIK098

Bz Calculation of TPS Linac Focusing Coils and a Toolkit for Bz Optimization

toolkit, focusing, electron, operation

4321

H.H. Chen, H.-P. Chang, C.L. Chen, C.-S. Fann, K.-K. Lin, Y.K. Lin, K.L. Tsai
NSRRC, Hsinchu, Taiwan

A set of focusing coils is installed along TPS linac beam centerline at low energy region (< 10 MeV) in order to confine the beam radius within 5 mm. The longitudinal magnetic field calculation along the beam centerline has been carried out in this study. The estimated Bz is obtained based on Biot-Savart law calculation. Then, it is verified by field measurement using Gauss meter at specific centerline locations. Calibration process is performed by comparing the calculated and measured Bz fields at selected operation settings. The comparison result is presented in this report. The linac operation experience indicates that tuning of the coil settings is critical concerning beam property optimization. Consequently, a Bz calculation toolkit is developed to cope with the multi-knobs optimization process while tuning of numerous focusing coils installed in the system at various locations. The applications of the Bz calculation toolkit is briefly described.

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THPIK106

Low Power RF Characterisation of the 400 Hz Photoinjector for CLARA

cathode, cavity, simulation, vacuum

4342

L.S. Cowie, P. Goudket, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
T.J. Jones
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

The CLARA High Repetition Rate Photoinjector comprises an S-band dual feed cavity and will operate at a repetition rate of up to 400 Hz and is capable of reaching an electric field strength on the cathode of 120 MV/m. The cavity was brazed after tuning and arrived at Daresbury Laboratory in February 2016. Extensive low power RF testing has been performed including measurements of the quality factors and coupling, pass-band mode frequencies, on axis field and RF repeatability of replacement of cathode plug. The dual feed coupler has been tuned and a Magic Tee type splitter installed. The photoinjector is now installed on the VELA beam line for commissioning and characterisation.

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THPIK109

The RF Distribution System for the ESS

detector, cavity, neutron, insertion

4352

T.R. Edgecock, N. Turner
University of Huddersfield, Huddersfield, United Kingdom
P. Aden, D. Naeem, R. Smith
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
A. Sunesson, R.A. Yogi
ESS, Lund, Sweden

The RF distribution system for the European Spallation Source will be one of the largest systems ever built. It will distribute the power from 146 power sources to the two types of ESS cavity at two different frequencies and will use one line per cavity for resilience. It will consist of a total of around 3.5 km of waveguide and coaxial line and over 1500 hundred bends. It is designed to transport this RF power over a distance of up to 40m per line, while minimising losses, avoiding reflections and allowing the monitoring of performance. This contribution will give an overview of the design of the system and its status. Installation is due to start in September 2017.

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THPIK126

Design of a Field-Emission X-Band Gun Driven by Solid-State RF Source

electron, gun, cavity, experiment

4399

E.A. Nanni, V.A. Dolgashev, J. Neilson, S.G. Tantawi
SLAC, Menlo Park, California, USA
B.E. Carlsten, J.W. Lewellen, D.C. Nguyen
LANL, Los Alamos, New Mexico, USA
M. Othman
UCI, Irvine, California, USA

We present the design of a field-emission X-band gun designed to be powered using a solid-state RF source. The source of the electron beam is a field emission nano-tip array. The RF gun is intended to be a beam source for 1 MeV solid-state driven linac for deployment on a satellite to map magnetic fields in the magnetosphere. The gun has to satisfy strict requirements on both average and peak power consumption, as well as rapid turn on time. In order to achieve low power consumption, the RF gun operates at relatively low accelerating gradient of 2 MeV/m. The beam exit energy is ~20 keV for an RF power 1.5 kW. Each cell of the RF gun is separately powered by commercially available, GaN high electron mobility transistors. In proof of principle experiments we successfully powered a 9.3 GHz accelerating cavity with a 100 W transistor and a 1% duty cycle.

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THPVA009

Transverse Beam Dynamics of an 8 MeV Electron Linac

emittance, solenoid, focusing, electron

4432

S. Sanaye Hajari, M. Dayyani Kelisani, H. Shaker
IPM, Tehran, Iran
S. Haghtalab
Shahid Beheshti University, Tehran, Iran

The IPM Electron Linac is an 8 MeV (upgradable to 11 MeV) electron linear accelerator under development at the Institute for Research in Fundamental Science (IPM), Tehran, Iran. The linac is mainly regarded as a research project providing hands-on experience in the accelerator science and technology. However, it could serve as an x-ray source or play the injector role for a larger facility. The linac consists of a thermionic gun followed by a travelling wave buncher joined to two accelerating tubes. The transverse focusing is provided by the solenoid mag-nets over the buncher and the accelerating structures. Using the code ASTRA, the transverse beam dynamics is studied and optimized in order to limit the RF emittance. Particularly, the effect of coupler asymmetry is investigated, a beam dynamics design of the solenoid channel is presented, and the effect of the solenoid misalignment on the beam quality is examined.

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THPVA011

Beam Dynamics Studies on Low and Medium Energy Beam Transport With Intense H⁻ Ions for J-PARC Linac

rfq, ion, solenoid, emittance

4439

S. Artikova
JAEA/J-PARC, Tokai-mura, Japan
K. Ikegami, T. Shibata
KEK, Ibaraki, Japan
Y. Kondo
JAEA, Ibaraki-ken, Japan

Japan Proton Accelerator Research Complex (J-PARC) linac was intensity-upgraded up to pulse current of 50 mA of H⁻ beam by replacing the ion source and the Radio Frequency Quadrupole(RFQ). We measured beam properties at the end of low energy beam transport (LEBT) line test stand under several conditions to investigate the transverse halo and space charge effects of an intense H⁻ ions. The LEBT is composed of two solenoid magnets. Furthermore, space charge neutralization effects in the residual gas were considered into account to describe the behavior of the beam phase space evolution. LEBT transmission efficiency, beam losses were estimated and optimization for beam matching into acceptance of the RFQ is studied. Two-solenoid based LEBT section is connected to the RFQ which is followed by a medium energy beam transport (MEBT) line. In this paper, we discuss the outcomes of beam emittance measurements and the results from beam dynamics simulations throughout LEBT and the RFQ acceleration.

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THPVA020

Distribution and Extreme Loss Analysis in the ESS Linac: A Statistical Perspective

proton, simulation, DTL, alignment

4458

A.L. Pedersen
Lund Institute of Technology (LTH), Lund University, Lund, Sweden
D. Anevski
Lund University, Lund, Sweden
M. Eshraqi, R. Miyamoto
ESS, Lund, Sweden

The report takes a statistical approach in the study of distribution evolution of the proton beam within the ESS linac and reports a new technique of pinpointing the non-linear space-charge effect of the propagating proton beam. By using the test statistic from the nonparametric Kolmogorov-Smirnov test the author visualises the change in the normalised distributions by looking at the supremum distance between the cumulative distribution functions in comparison, and the propagation of the deviation throughout the ESS linac. This approach identifies changes in the distribution which may cause losses in the linac and highlights the parts where the space-charge has big impact on the beam distribution. Also, an Extreme Value Theory approach is adopted in order to quantify the effects of the non linear forces affecting the proton beam distribution.

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THPVA046

Thermo Mechanical Study of the ESS DTL

DTL, simulation, quadrupole, feedback

4537

P. Mereu, M. Mezzano, C. Mingioni, M. Nenni
INFN-Torino, Torino, Italy
F. Grespan, A. Palmieri, A. Pisent
INFN/LNL, Legnaro (PD), Italy

The Drift Tube Linac (DTL) of the European Spallation Source (ESS) is designed to operate at 352.2 MHz with a duty cycle of 4 % (3 ms pulse length, 14 Hz repetition period) and will accelerate a proton beam of 62.5 mA pulse peak current from 3.62 to 90 MeV. In this paper the main issues regarding the thermo-mechanical 3D details of the DTL are addressed and a Computational Fluid Dynamics (CFD) model is proposed and validated against the experimental data. The results of these simulations are used to properly design the DTL cooling system.

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THPVA057

The Primary Control Network of HLS II

network, controls, laser, synchrotron

4573

W. Wang, L. Lin, F.F. Wu, Q. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

To meet the accuracy requirement of alignment and installation of HLS', the high accuracy control network is necessary. The high accuracy primary control network will provides reliable reference to the local control network. After optimization design that using Monte-Carlo method, according to the structure characteristic of HLS', the primary control network is measured by several different instruments, such as: Laser tracker, Total station and plummet. The accuracy of actual primary control network meets the design requirements, it provides strong foundation for subsequent project.

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THPVA059

Development of a New High Power RF Window for S-band Linac

klystron, vacuum, cavity, high-voltage

4576

W.H. Hwang, J.Y. Choi, Y.D. Joo, S.H. Kim, B.-J. Lee
PAL, Pohang, Kyungbuk, Republic of Korea
S.J. Roh
Vitzrotech Co., Ltd., Ansan City, Kyunggi-Do, Republic of Korea

A prototype rf window was developed in collaboration with Pohang Accelerator Laboratory (PAL) and domestic companies. The PAL designed the S-band TE012 rf window and conducted the high power performance tests of single rf window to verify the operation characteristics for the application to the PLSII Linac. The test was performed in the in-situ facility consisting of a modulator, klystron, waveguide network, vacuum system, cooling system, and rf analyzing equipment. As the test results with SLED, no breakdown appeared up to 75 MW peak power with 4.5 micro-seconds rf pulse width at a repetition rate of 10 Hz. The test results with the current operation level of PLSII Linac confirms that the rf window well satisfies the criteria of PLS Linac operation.

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THPVA061

Study of the Cooling and Vacuum Systems of a Miniature 12 MeV Race-Track Microtron

vacuum, simulation, ion, microtron

4582

Yu.A. Kubyshin, X. Escaler, A. Viladomiu
UPC, Barcelona, Spain
V.I. Shvedunov
SINP MSU, Moscow, Russia

With the aim of optimization, numerical simulations of the cooling and vacuum systems of a compact 12 MeV race-track microtron (RTM) which is under construction at the Technical University of Catalonia have been carried out. The hydraulic and thermal performance of the cooling system for various flow rates has been studied using the Computational Fluid Dynamics (CFD) software. A CFD model, previously validated with experimental pressure loss results, has permitted to simulate the cooling fluid temperature, inner wall temperatures and heat trans-fer coefficients at different sections of the RTM accelerating structure. Conclusions concerning the current design and its possible optimization are discussed. Simulations of the RTM high vacuum conditions have been performed using the Monte-Carlo simulation package Molflow+. The pressure in the vacuum chamber, pumping tube conductance and maximum allowed throughput have been calculated. Also results of the vacuum chamber pumping out sessions are reported.

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THPVA065

Working Concept of 12.5 kW Tuning Dump at ESS

simulation, proton, target, neutron

4591

Y. Lee, M. Eshraqi, S. Ghatnekar Nilsson, Y.I. Levinsen, R. Miyamoto, S. Molloy, M. Möller, A. Olsson, T.J. Shea, C.A. Thomas, M. Wilborgsson
ESS, Lund, Sweden
F. Sordo
ESS Bilbao, Zamudio, Spain

The linac system at the European Spallation Source (ESS) will deliver 2~GeV protons at 5~MW beam power. The accelerated protons from the linac will be transported to the rotating tungsten target by two bending magnets. A tuning beam dump will be provided at the end of the linac, downstream of the first bending magnet. This tuning dump shall be able to handle at least 12.5 kW of beam power. In this paper, we present the working concept of the tuning dump. The impact of the proton beam induced material damage on the operational loads and service lifetime of the tuning dump is analysed. A number of particle transport and finite-element simulations are performed for the tuning beam modes.

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THPVA066

TPS LINAC Temperature Monitoring System

PLC, monitoring, EPICS, controls

4595

C.L. Chen, H.-P. Chang, C.-S. Fann, K.-K. Lin, K.L. Tsai
NSRRC, Hsinchu, Taiwan

TPS Linac has been providing with electron beams which conform to the specifications to the requirement since 2014. Firstly electrons are extracted from electron gun (e-gun), and they are accelerated and gained energy from 90 keV to 150 MeV in three linear accelerating sections. Then electron beams are successfully injected to the booster ring via Linac to Booster (LTB) transport line. Providing a stable and reliable operating system is next priority objective and so a temperature monitoring system is established. This temperature monitoring system is used to monitor the temperatures for each Linac sub-system and its surrounding environment. By using this temperature monitoring system, it helps to understand the relation between beam energy and working temperature for each sub-system, when Linac is under normal operation. This report will detail the temperature monitoring components, including thermalcouples, PLC thermal modules, PLC programming and graphic user interface (GUI). By integrating with EPICS, this monitoring system is becoming a complete solution for ensuring any possible influence due to thermal effects.

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THPVA071

A Method to Design Multi-Cell Accelerator Cavities

DTL, cavity, drift-tube-linac, focusing

4610

S.S. Kurennoy
LANL, Los Alamos, New Mexico, USA

An efficient method for designing multi-cell accelerator cavities has been developed. It is similar to the approach used by Superfish codes for drift-tube linacs (DTL), where a few single cells at representative beam velocities are tuned in 2D and their geometrical parameters are interpolated to cover the required beam-velocity range. The method is implemented using 3D electromagnetic (EM) modeling with CST MicroWave Studio, which allows its application for various types of resonators, e.g., for H-mode cavities. Interpolating results of 3D EM design of tuned representative single-cell cavities leads to a 3D multi-cell cavity model that can be finalized with just a few small adjustments. As a challenging application example, we design multi-cell resonators of three types - cross-bar (CH) and inter-digital (IH) H-mode, as well as DTL - for accelerating muons in the velocity range of v/c = 0.08-0.3, and compare their performance.

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THPVA086

Beam Dynamics Studies of an Accelerating Tube for 6 MeV Electron LINAC

emittance, electron, simulation, space-charge

4657

S. Zarei
Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran
F. Abbasi
Shahid Beheshti University, Tehran, Iran
S. Ahmadiannamin
ILSF, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran
M. Lamehi
IPM, Tehran, Iran

Side coupled standing wave accelerating tubes are widely used in a low energy linear accelerator because of relatively high accelerating gradient and low sensitivity to construction tolerances. The effective interaction of particles and electromagnetic fields is important for accelerate electrons to intended energy with the greatest efficiency and beam quality output. In this paper, we present the beam dynamics of a 6 MeV Side coupled standing wave accelerating tube using a space charge tracking algorithm (ASTRA). The designed accelerating tube that feeds by a maximum power of 2.6 MW resonant at frequency of 2998.5 MHz in pi/2 mode. 37.5 percent capture efficiency, 6.82 pi-mm-mrad horizontal emittance, 6.78 pi-mm-mrad vertical emittance, 2.24 mm horizontal and vertical beam size and 1079 keV energy spread of the output beam have been determined from the results of beam dynamics studies in ASTRA

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THPVA087

Thermal and Mechanical Analysis of 3 GHz Side Coupled RF Cavity for Medical Linacs

cavity, simulation, electron, operation

4660

M. Mohseni Kejani, F. Abbasi
Shahid Beheshti University, Tehran, Iran
S. Ahmadiannamin
ILSF, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran
S. Zarei
Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran

Medical linear accelerators have wide applications for cancer treatment in the world. Side coupled RF cavities was used in this accelerators for production of X-ray in range of energies between 4 to 25 MeV. Usually, the RF source is magnetron with lower cost in comparison to klystron in this type of applications. Side coupled cavity is a biperiodic structure with sensitive performance to operational thermal and mechanical conditions. In this paper, thermal and mechanical simulations for a period of the structure are presented.

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THPVA089

Optimization Study on Production of Mo-99 Using High Power Electron Accelerator Linac

target, electron, photon, neutron

4667

A. Taghibi Khotbeh-Sara, F. Rahmani
KNTU, Tehran, Iran
S. Ahmadiannamin
ILSF, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran

Molybdenum-99 is used for preparing 99mTc, which is the most widely used isotope in nuclear medicine. As a recent and now shortages in reactor-based supplies of 99Mo/99mTc and also some problems due to the time limitation in a direct production approach such as 100Mo(p, 2n)99mTc reaction by cyclotrons, many of developed countries have started the plan to produce this type of radioisotopes based on the production of non-reactor methods, especially by linac. In this study, the investigation on 99Mo production based on high power electron linac as an alternative approach has been performed, in which the use of 100Mo(gamma, n)99Mo (photoneutron production) has been proposed.

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THPVA090

The TOP-IMPLART Linac: Machine Status and Experimental Activity

proton, klystron, target, framework

4669

C. Ronsivalle, A. Ampollini, G. Bazzano, P. Nenzi, L. Picardi, V. Surrenti, E. Trinca, M. Vadrucci
ENEA C.R. Frascati, Frascati (Roma), Italy

Funding: Regione Lazio in the framework of the TOP-IMPLART Project
The TOP-IMPLART (Intensity Modulated Proton Therapy Linear Accelerator for Radiotherapy) linac is a 150 MeV pulsed proton linear accelerator for protontherapy applications under realization, installation and progressive commissioning at ENEA. It is the first linac running with 3GHz SCDTL (Side Coupled DTL) accelerating modules. These constitute the first two sections of the whole linac up to 71 MeV proton energy, while the accelerating structure of the following part of the accelerator is under definition. Each SCDTL section is powered by a 10 MW peak power klystron. The first section, consisting of 4 modules (7 to 35 MeV) has been completed and it is operational at low repetition rate (25 Hz). The second section, consisting of other 4 modules (up to 71 MeV), is currently under executive design. The output beam at each stage of the progressive commissioning is fully characterized. The beam is routinely employed in radiobiology experiments and detector evaluation. The paper presents the actual status of the machine, installation, beam characterization and an overview of the experimental activity results.

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THPVA091

Diagnostics Methods for the Medium Energy Proton Beam Extracted by the TOP IMPLART Linear Accelerator

proton, radiation, detector, diagnostics

4673

M. Vadrucci, A. Ampollini, P. Nenzi, L. Picardi, C. Ronsivalle, E. Trinca
ENEA C.R. Frascati, Frascati (Roma), Italy
E. Cisbani, F. Ghio
ISS, Rome, Italy
M. Marinelli, G. Prestopino, G. Verona Rinati
INFN - Roma Tor Vergata, Roma, Italy
C. Placido
University of Rome La Sapienza, Rome, Italy

Funding: This material is based upon work supported by the Regione Lazio/Italy
The Italian TOP IMPLART project aims to develop the first proton linear accelerator for cancer radiotherapy. A 150MeV proton LINAC is under construction at the ENEA Frascati research center: currently the machine is composed by a 7MeV injector operating at 425MHz and four 3GHz SCDTL modules producing a proton beam of 35MeV. Operational procedures for irradiation of samples need careful measurements of average beam current, transverse distribution and pulse charge by different monitor types placed along the beam line. The injected current in the high frequency segment of the accelerator is measured by a Fast Current Transformer (FCT) at the entrance of the SCDTL modules and the pulsed current of the accelerated beam is measured by a second FCT, placed in air, at the exit. The output proton beam shape and intensity are measured by an integral ionization chamber, a double (XY) multistrip ionization chamber, a synthetic single crystal diamond detector and a Faraday cup. In this work, the results of these multiple diagnostic tools applied to different operating conditions of the machine are presented.

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THPVA098

Development of a 3.95 Mev X-Band Linac-Driven X-Ray Combined Neutron Source

neutron, target, experiment, detector

4692

J.M. Bereder, K. Dobashi, Y. Mitsuya, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
M. Ishida, Y. Ohshima
PWRI, Ibaraki, Japan
J. Kusano
Accuthera Inc., Kawasaki, Kanagawa, Japan
Y. Takahashi
The University of Tokyo, Tokyo, Japan
Y. Tanaka
The University of Tokyo, Institute of Industrial Science, Tokyo, Japan

Funding: Council for Science, Technology and Innovation (CSTI), Cross-Ministrial Strategic Innovation Promo-tion Program (SIP), Japan Science and Technoogy Agency (JST)
The existing non-destructive inspection method employed for concrete structures uses high energy X-rays to detect internal flaws in concrete structures and iron reinforcing rods. In addition to this conventional method, the authors are developing an innovative inspection system that uses a mobile compact linac-driven neutron source that utilizes neutron backscattering, to measure the moisture content in concrete structures and estimate the corrosion probability distribution of iron reinforcing rods. By combining the knowledge of the moisture distribution in concrete structures with the information of its inner structure, the remaining life of concrete structures can be estimated. Further experiments will be conducted in the laboratory, and the moisture detection experiment in the real bridge is scheduled for 2017.

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THPVA102

Structural Analysis and Evaluation of Actual PC Bridge Using 950 keV/3.95 MeV X-Band Linacs

site, experiment, detector, target

4701

H. Takeuchi, R. Yano
The University of Tokyo, Tokyo, Japan
K. Dobashi, Y. Mitsuya, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
M. Ishida, Y. Ohshima
PWRI, Ibaraki, Japan
J. Kusano
Accuthera Inc., Kawasaki, Kanagawa, Japan
I. Ozawa
The University of Tokyo, The School of Engineering, Tokyo, Japan

Funding: This work was supported by Council for Science, Technology and Innovation(CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP) (Funding agency: JST).
In Japan, bridges constructed in the highly economic growth era are facing to aging problem and advanced maintenance methods have been strongly required recently. To meet this demand, we develop the on-site inspection system using 950 keV/3.95 MeV X-band (9.3 GHz) linac X-ray sources*. These systems can visualize in seconds the inner states of bridge, including cracks of concrete, location and state of tendons (wires) and other imperfections. We focused on the inspection for wires which are critical to the safety of bridge. At the on-site inspections, the X-ray inspection system exhibited sufficient accuracy to detect the wire's corrosion. We also evaluated the maximum thickness of concrete to which our system can be applied. Using the 950 keV system, we conducted on-site inspection for real bridges and performed structural analysis to evaluate the bearing capacity of the bridge using finite element method. We plan to apply the 3.95 MeV linac for actual bridge inspection to extend the applicable range in 2017. For accurate visualization, the parallel motion CT technique for bridge inspection is in progress.
* Mitsuru Ueaska et al, On-site nondestructive inspection by upgraded portable 950keV/3.95MeV X-band linac x-ray sources, J. Phys. B: At. Mol. Opt. Phys. 47(2014) 234008 (9pp)

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THPVA103

Design of Injector for Carbon Cancer Therapy

DTL, rfq, ion, ion-source

4704

A. Yamaguchi, K. Nakayama, K. Okaya, K. Sato, T. Takeuchi, J. Watanabe
Toshiba, Yokohama, Japan
N. Hayashizaki
RLNR, Tokyo, Japan

An Injector which consisted of a Radio Frequency Quadrupole (RFQ) and Drift Tube Linacs (DTLs) were designed for carbon cancer therapy system. An extraction energy of RFQ was 0.6 MeV/u, an extraction energy of DTLs was 4 MeV/u, frequency is 200MHz. To apply a compact solid-state power amplifier system, we designed one high-Q RFQ and two high-Q DTLs which had a triplet Quadrupole magnet between DTLs.

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THPVA105

A Novel Side Coupling Standing-Wave Accelerating Structure for a Medical Linac

cavity, coupling, electron, impedance

4710

Zh. X. Tang, Z.H. Bai, Y.J. Pei
USTC/NSRL, Hefei, Anhui, People's Republic of China

A novel side coupling standing-wave (SW) accelerat-ing tube for low energy medical linac has been designed that operating frequency is 2998 MHz, operating mode is ', final energy is 6 MeV and beam current is 130 mA. A novel bridge hole between an accelerating cavity and coupling cavity has been utilized to reduce the mutual effect between two cavities and improve the anti-jamming capability and the long term stability. The inner end plate of the inlet of the first accelerating cavity in-cludes the nose cone to realize self-focusing in transverse to improve the beam quality. The simulation of the elec-tromagnetic field of structure and beam dynamic has been carried out with the SUPERFISH, CST Microwave studio and Parmela, respectively.

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THPVA126

Monte Carlo Simulation of Electron Beam Irradiation System for Natural Rubber Vulcanization

electron, simulation, vacuum, target

4747

K. Kosaentor
IST, Chiang Mai, Thailand
E. Kongmon, S. Rimjaem, J. Saisut, C. Thongbai
Chiang Mai University, Chiang Mai, Thailand

This paper presents the results of Monte Carlo simulation of electron beam irradiation system for natural rubber vulcanization, which is underway at Chiang Mai University in Thailand. The accelerator system can produce electron beams with adjustable energy and current in the ranges of 0.5-4 MeV and 10-100 mA, respectively. The electron beam exits from vacuum environment in the accelerator to the atmospheric air through a titanium (Ti) window. The electron dose absorption in Ti window and air was calculated by using the program GEANT4. The simulation results show that 50 μm Ti foil causes the energy loss of 1 and 18% for the beam of 4.0 and 0.5 MeV, respectively. The air gap between vacuum window and rubber surface is adjustable from 180 mm to 540 mm. The total beam energy loss of around 8-17% and 1-3% from the initial energies of 0.5 and 4 MeV, respectively. The proper depth of the natural rubber for the vulcanization process is 0.13 to 1.68 cm with the surface dose of 5.32 kGy for 0.5 MeV electron beam and 3.34 kGy for 4.0 MeV electron beam at the pulse repetition rate of 200 Hz. Accordingly, the treatment time of around 10-15 second per irradiated point is required.

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THPVA134

Coupled Longitudinal and Transverse Beam Dynamics Studies for Hadron Therapy Linacs

simulation, proton, cyclotron, cavity

4772

R. Apsimon, G. Burt, S. Pitman
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
A.F. Green, H.L. Owen
UMAN, Manchester, United Kingdom

Precise proton therapy planning can be assisted by augmenting conventional medical imaging techniques with proton computed tomography (pCT). For adults this requires an incident proton energy up to at least 330 MeV, an energy not readily accessible using cyclotrons. We are presently constructing a prototype of the ProBE 54 MV/m 3GHz post-cyclotron booster linac as a compact method to achieve 330 MeV in the context of the Christie Hospital proton therapy centre, to be tested in the research room there. In this paper, we present beam dynamics studies and tracking simulations of proton beams through the booster region. The longitudinal and transverse particle transmission is calculated from tracking simulations and compared to theoretical models to help understand how best to optimise the optics design through the ProBE region.

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THPVA135

ProBE: Proton Boosting Extension for Imaging and Therapy

proton, cavity, cyclotron, booster

4776

S. Pitman, R. Apsimon, G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
A.F. Green, H.L. Owen
UMAN, Manchester, United Kingdom
A. Grudiev, A. Solodko, W. Wuensch
CERN, Geneva, Switzerland

Funding: This work was funded by STFC
The ProBE linac aims at accelerating protons from a particle therapy cyclotron to the c.330 MeV required for proton tomography. To obtain the c. 55 MV/m gradients required to achieve 100 MeV gain in a suitably short distance, we propose the use of a high-gradient S-band side-coupled standing-wave structure. In this paper we discuss the progress toward the testing of the prototype at the S-box facility at CERN.

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THPVA140

Superconducting Gantry Design for Proton Tomography

proton, dipole, quadrupole, optics

4795

E. Oponowicz, H.L. Owen
UMAN, Manchester, United Kingdom

Precise proton therapy planning can be assisted by augmenting conventional medical imaging techniques with proton computed tomography (pCT). For adults this requires an incident proton energy up to around 330 MeV, requiring superconducting magnets if an imaging gantry is to replace a conventional 230-250 MeV gantry in the same space. Here we present optics considerations for a superconducting gantry to deliver 330 MeV protons within the context of the future Christie Hospital proton therapy centre, where it is proposed to increase the proton energy in the future with a booster linac.

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THPVA146

Robust Linac Platform for Wide Replacement of Radioactive Sources

vacuum, impedance, simulation, coupling

4805

A.V. Smirnov, M.A. Harrison, A.Y. Murokh, A.Yu. Smirnov
RadiaBeam Systems, Santa Monica, California, USA
R.B. Agustsson, S. Boucher, T.J. Campese, J.J. Hartzell, K.J. Hoyt
RadiaBeam, Santa Monica, California, USA
E.A. Savin
MEPhI, Moscow, Russia

Funding: This work was supported by the U.S. Department of Energy (awards No. DE-SC-FOA-0011370).
To improve public security and prevent the diversion of radioactive material for Radiation Dispersion Devices, development of an inexpensive, portable, easy-to-manufacture linac system is very important. Tubular structure with parallel pairs of rods crossed at 90 degrees suggests as high as 36% inter-cell coupling due to inherent compensation along with still substantial shunt impedance. Simultaneously it offers simplified brazing process and may dramatically simplify tuning of the entire structure. A novel design of a multi-cell, single-section, X-band structure for replacement of Ir192 source is presented.

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THPVA147

KlyLac Conceptual Design for Borehole Logging

klystron, cavity, electron, vacuum

4808

A.V. Smirnov, S. Boucher, M.A. Harrison, A.Y. Murokh
RadiaBeam Systems, Santa Monica, California, USA
R.B. Agustsson, D. Chao, J.J. Hartzell, K.J. Hoyt, A.Yu. Smirnov
RadiaBeam, Santa Monica, California, USA
E.A. Savin
MEPhI, Moscow, Russia

Funding: This work was supported by the U.S. Department of Energy (award No. DE-SC0015721).
Linac-based system for borehole logging exploits KlyLac approach combing klystron and linac sharing the same electron beam, vacuum volume, and RF net-work. The conceptual design tailors delivering 3.5-4 MeV electrons within 3.5 inch borehole at ambient temperatures 150 degrees C to replace 137Cs, >1 Ci source used in borehole logging. The linac part is based on a very robust, high group velocity, cm-wave, standing wave accelerating structure. The design concept features i) self-oscillation analog feedback that automatically provides modal stability; ii) ferrite-free isolation of the klystron; and iii) long accelerating section with large (0.3%) frequency separation between adjacent modes; and iv) low-voltage klystron.

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FRXBA1

Compact and Efficient Accelerators for Radioisotope Production

cyclotron, target, electron, isotope-production

4824

C. Oliver
CIEMAT, Madrid, Spain

The production in an efficient way of radioisotopes for medical use is crucial. With the closing in the next ten years of nuclear reactors the problem of the production of some of them is being critical. New approaches of producing these radioisotopes via accelerators are being developed. In the other hand a big effort is being made for making the accelerators for the production of radioisotopes more compact, efficient and with an optimized cost. This paper describes the recent advances in this kind of accelerator techniques.

Slides FRXBA1 [2.797 MB]

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FRXCB1

The Energy Efficiency of High Intensity Proton Driver Concepts

proton, cavity, cyclotron, SRF

4842

V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
J. Grillenberger, M. Seidel
PSI, Villigen PSI, Switzerland
S.-H. Kim
ORNL, Oak Ridge, Tennessee, USA
M. Yoshii
KEK, Tokai, Ibaraki, Japan

For MW class proton driver accelerators the energy efficiency is an important aspect; the talk reviews the efficiency of different accelerator concepts including s.c./n.c. linac, rapid cycling synchrotron, cyclotron; the potential of these concepts for very high beam power is discussed.

Slides FRXCB1 [2.964 MB]

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