IPAC2017 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOXAA1	Commissioning of the European XFEL Accelerator	linac, operation, electron, undulator	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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MOYAA1	Approaching the Nominal Performance at the LHC	luminosity, operation, experiment, injection	13
	J. Wenninger CERN, Geneva, Switzerland
	In 2015 the Large Hadron Collider (LHC) restarted for Run 2 after an almost two year long shutdown to consolidate the machine for operation at nominal beam energy. Following a month of recommissioning and training of the magnet system, the LHC operated for the first time at an energy of 6.5 TeV. The aim of this first year was to master operation at the higher energy and with beams of 25 ns spacing. In 2016 the performance could be pushed based on the experience of 2015, culminating with a luminosity 40% above the design value of 10³⁴ cm^-2s⁻¹. The status of the machine operation, performance and prospects for the rest of Run 2 and Run 3 will be discussed.
	Slides MOYAA1 [4.639 MB]
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MOZA1	Electron Cloud Effects at the LHC and LHC Injectors	electron, operation, simulation, dipole	30
	G. Rumolo, H. Bartosik, E. Belli, P. Dijkstal, G. Iadarola, K.S.B. Li, L. Mether, A. Romano, M. Schenk, F. Zimmermann CERN, Geneva, Switzerland E. Belli University of Rome La Sapienza, Rome, Italy P. Dijkstal TU Darmstadt, Darmstadt, Germany M. Schenk EPFL, Lausanne, Switzerland
	Electron cloud effects are one of the main limitations of the performance of the LHC and its injectors. Enormous progress has been done in the simulation of the electron cloud build-up and of the effects on beam stability while mitigation measures have been identified and implemented (scrubbing, low secondary electron yield coatings, etc.). The above has allowed reaching nominal beam parameters in the LHC during Run 2. A review of the studies and results obtained and the strategy and expected performance for the High Luminosity operation of the LHC will be presented.
	Slides MOZA1 [12.855 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOZA1
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MOPAB014	Generating Low Beta Regions With Quadrupoles for Final Muon Cooling	quadrupole, simulation, collider, betatron	107
	J.G. Acosta, L.M. Cremaldi, T.L. Hart, S.J. Oliveros, D.J. Summers UMiss, University, Mississippi, USA D.V. Neuffer Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359 Muon beams and colliders are rich sources of new physics, if muons can be cooled. A normalized rms transverse muon emittance of 280 microns has been achieved in simulation with short solenoids and a betatron function of 3 cm. Here we use ICOOL, G4beamline, and MAD-X to explore using a 400 MeV/c muon beam and strong focusing quadrupoles to approach a normalized transverse emittance of 100 microns and finish 6D muon cooling. The low beta regions produced by the quadrupoles are occupied by dense, low Z absorbers, such as lithium hydride or beryllium, that cool the beam. Equilibrium transverse emittance is linearly proportional to the beta function. Reverse emittance exchange with septa and/or wedges is then used to decrease transverse emittance from 100 to 25 microns at the expense of longitudinal emittance for a high energy lepton collider. Work remains to be done on chromaticity correction.
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MOPAB016	Beam Diagnostic and Control Systems for AREAL 50 MeV Linac	controls, electron, diagnostics, linac	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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MOPAB023	ESS Emittance Measurements at INFN CATANIA	ion, ion-source, simulation, proton	123
	O. Tuske, P. Daniel-Thomas, J.F. Denis, Y. Gauthier, T.J. Joannem, N. Misiara, V. Nadot, G. Perreu, F. Senée, V. Silva CEA/IRFU, Gif-sur-Yvette, France L. Celona, L. Neri INFN/LNS, Catania, Italy B. Cheymol, T.J. Shea ESS, Lund, Sweden I. Chu, M. Monteremand CEA LITEN, CEA Grenoble, Grenoble, France Ø. Midttun University of Bergen, Bergen, Norway T.V. Vacher CEA/DSM/IRFU, France
	Beam characteristics at low energy are an absolute necessity for an acceptable injection in the next stage of a linear accelerator, and are also necessary to reduce beam loss and radiation inside the machine. CEA is taking part of ESS linac construction, by designing Emittance Measurement Units (EMU) for the Low Energy Beam Transport (LEBT). The EMU are designed to qualify the proton beam produced by the INFN Catania ion source. This measurement has been decided to be time resolved, allowing to follow the beam emittance reduction, during the pulse length. A 1Mhz acquisition board controlled by EPICS save raw datas to an archiver in order to be able to post process the measurements for time resolution. The design corresponds to an Allison's scanner, using entrance and exit slits, electrostatic plates and a faraday cup. The beamstopper protects the device and can be removable to fit to beam power. It has been manufactured by the CEA/LITEN with copper tungsten HIP technique. This article report the first measurements on the ESS injector at INFN CATANIA.
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MOPAB041	Quadrupole Scan Measurements in the Beam Transport Line between DESY II and PETRA III	quadrupole, focusing, synchrotron, beam-transport	174
	J. Keil, H. Ehrlichmann, G.K. Sahoo, R. Wanzenberg DESY, Hamburg, Germany
	PETRA III is a 6 GeV third generation synchrotron light source in Hamburg, Germany. The storage ring is operated with a typical beam current of 100 mA and is running in top-up mode. The beam delivered to PETRA III is accelerated by a fast cycling booster synchrotron (DESY II), extracted in a 203 m long beam transport line (E-Weg) and injected afterwards into PETRA III. In the framework of PETRA IV upgrade scenarios the potential for decreasing the extracted emittance from DESY II has been investigated which can be achieved by lowering the extraction energy to 5 GeV and increasing the focusing in DESY II. In addition measuring the emittance of the extracted beam from DESY II and the optics in the beam transport line can help to better understand and improve the injection efficiency of PETRA III. By changing the quadrupole strength and measuring the beam size downstream on a screen monitor in the E-Weg the emittance of DESY II and the Twiss functions at the quadrupole in the E-Weg have been determined. Measurements at different energies and tunes of DESY II will be shown and compared with calculations.
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MOPAB042	Two-Dimensional Synchrotron Radiation Interferometry at PETRA III	synchrotron, radiation, synchrotron-radiation, operation	177
	A.I. Novokshonov, A. Potylitsyn TPU, Tomsk, Russia G. Kube DESY, Hamburg, Germany
	Synchrotron radiation interferometry is widely used at modern 3rd generation light sources in order to measure transverse electron beam sizes. The technique is based on probing of the spatial coherency of synchrotron radiation in the visible spectral region. The light source PETRA III at DESY (Hamburg, Germany) is using this type of interferometer since several years in order to resolve vertical emittances of about 10 pm.rad. In order to overcome some inherent disadvantages in this setup, a new optical diagnostics beamline was recently commissioned with a two-dimensional interferometer, thus allowing to measure beam sizes in both transverse planes simultaneously. This contribution summarizes the status of the interferometer with first operational experience and describes systematical studies concerning the stability and possibilities to increase the sensitivity on small beam sizes using an intensity imbalance technique.
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MOPAB047	Electron Beam Phase Space Tomography at the European XFEL Injector	electron, quadrupole, FEL, optics	196
	M. Scholz, B. Beutner DESY, Hamburg, Germany
	The FEL process is determined by the 6D phase space distribution of relativistic electron bunches. Experimental reconstructions of these distributions are therefore a step foreward to understand the beam dynamics and to optimize FEL operation. The reconstructions of the transverse phase spaces can be acieved with tomographic methods. In the injector of the European XFEL, measurements for the reconstruction of the phase spaces were carried out using phase advance scans with multiple quadrupoles. The beam sizes were kept optimized at the measurement screen. A transversely deflecting cavity (TDS) was used to streak the beam vertically. That allows to do longitudinally slice resolved measurements of the horizontal phase space. The horizontal streak required for the slice measurements in the vertical plane was achieved with a correlated linear energy spread and dispersion. In this paper, we present measurement results showing longitudinal slice resolved reconstructions of the transverse phase spaces taken in the European XFEL injector.
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MOPAB051	Progress in FLASH Optics Consolidation	optics, undulator, gun, laser	211
	J. Zemella, M. Vogt DESY, Hamburg, Germany
	FLASH is the superconducting soft X-ray Free Electron Laser in Hamburg at DESY, Germany. A precise knowledge of the beam optics is a key aspect of the operation of a SASE FEL. A campaign of optics consolidation has started in 2013 when the second beam line FLASH2 was installed downstream of the FLASH linac. We give an update on progress of this effort and on recent results.
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MOPAB052	A Transverse Deflection Structure with Dielectric-Lined Waveguides in the Sub-THz Regime	electron, simulation, impedance, laser	215
	F. Lemery University of Hamburg, Hamburg, Germany R.W. Aßmann, K. Flöttmann, T. Vinatier DESY, Hamburg, Germany
	Longitudinal bunch measurements are typically done with rf-powered transverse deflection structures with operating frequencies 1-12~GHz. We explore the use of mm-scale, THz-driven, dielectric-lined cylindrical waveguides as transverse deflectors by driving the fundamental deflecting mode of the structure, the HEM₁₁. We give a brief overview of the physics, history, and provide an example with a 5~MeV beam using {\sc astra} and {\sc CST-MWS}. This work was supported by the European Research Council (ERC) under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant agreement no. 609920
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MOPAB064	Photoinjector Emittance Measurement at STAR	gun, electron, solenoid, simulation	257
	A. Bacci, C. Curatolo, I. Drebot, L. Serafini, V. Torri Istituto Nazionale di Fisica Nucleare, Milano, Italy R.G. Agostino, R. Barberi, V. Formoso, M. Ghedini, F. Martire, C. Pace UNICAL, Arcavacata di Rende, Italy D. Alesini, M. Bellaveglia, J.J. Beltrano, F.G. Bisesto, G. Borgese, B. Buonomo, G. Di Pirro, G. Di Raddo, A. Esposito, A. Gallo, A. Ghigo, F. Iungo, A. Papa, L. Pellegrino, A. Stella, C. Vaccarezza, S. Vescovi INFN/LNF, Frascati (Roma), Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy G. D'Auria, A. Fabris, M. Marazzi Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy V. Petrillo Universita' degli Studi di Milano, Milano, Italy A. Policicchio UniCal & INFN CS, Arcavacata di Rende (CS), Italy E. Puppin Politecnico/Milano, Milano, Italy M. Rossetti Conti Universita' degli Studi di Milano & INFN, Milano, Italy
	STAR is an advanced Thomson source of monochromatic and tunable, ps-long, polarised X-ray beams in the 40-140 keV range. The commissioning has started at the Univ. of Calabria (Italy). The light source is driven by a high-brightness, low-emittance electron beam produced in a LINAC allowing for the source tunability and spectral density. This note reports on an emittance measurement schema based on the insertion of a slit mask in the vacuum chamber dedicated to the photocathode laser entrance. Results of the simulation of the measurement technique are reported, and the use of the data for the optimisation of the accelerator performance are detailed. The experimental setup and the application developed in EPICS for image recording and analysis are also described.
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MOPAB107	A Method for Determining the Roll Angle of the CLIC Accelerating Structures From the Beam Shape Downstream of the Structure	octupole, collider, simulation, experiment	368
	J. Ögren, V.G. Ziemann Uppsala University, Uppsala, Sweden W. Farabolini CEA/DSM/IRFU, France
	The Compact Linear Collider (CLIC) accelerating structures have a four-fold symmetry from the radial waveguides for damping higher order modes. This symmetry allows for an octupole component of the rf fields to co-propagate with the main accelerating field. The effect of this octupole mode has been observed at the CLIC test facility 3. In CLIC the accelerating structures are mounted together on a moveable girders. There are four vertical and four horizontal actuators on the girder, which allows for 5D control in a limited range and for instance we can roll the girder. By observing the beam shape perturbed by the octupole field on a screen downstream from the structure we can determine the roll angle and thus align the structure azimuthally. Here we discuss a possible method and show some preliminary results.
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MOPAB109	Operational Experience with Luminosity Scans for Beam Size Estimation in 2016 LHC Proton Physics Operation	luminosity, operation, proton, simulation	374
	M. Hostettler LHEP, Bern, Switzerland K. Fuchsberger, G. Papotti CERN, Geneva, Switzerland
	Luminosity scans were regularly performed at the CERN Large Hadron Collider (LHC) as of 2015 as a complementary method for measuring the beam size. The CMS experiment provides bunch-by-bunch luminosities at sufficient rates to allow evaluation of bunch-by-bunch beam sizes, and the scans are performed in the horizontal and vertical plane separately. Closed orbit differences between bunches can also be derived by this analysis. During 2016 LHC operation, these scans were also done in an automated manner on a regular basis, and the analysis was improved to significantly reduce the systematic uncertainty, especially in the crossing plane. This contribution first highlights the recent improvements to the analysis and elaborates on their impact. The measured beam sizes during 2016 proton physics operation are then shown and compared to measurements from synchrotron light telescopes and estimates based on the absolute luminosities of the LHC experiments.
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MOPAB110	Comparison of Transverse Emittance Measurements in the LHC	luminosity, experiment, detector, operation	377
	M. Hostettler, R. Alemany-Fernández, F. Alessio, M. Ferro-Luzzi, K. Fuchsberger, G. Iadarola, R. Matev, S. Papadopoulou, Y. Papaphilippou, G. Papotti, G. Trad CERN, Geneva, Switzerland F. Antoniou The University of Liverpool, Liverpool, United Kingdom G.R. Coombs University of Glasgow, Glasgow, United Kingdom T.B. Hadavizadeh Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	Transverse emittance measurement in a collider is of crucial importance for understanding beam dynamics observations and evaluating the machine performance. Devices measuring the beam emittance face the challenge of dealing with considerable systematic errors that can compromise the quality of the measurement. Having different instruments or techniques that provide beam size estimations in order to compare the outcome and give an unbiased value of the emittance is very important in a collider. The comparison of the different results is as well very useful to identify possible problems in a given equipment which could remain unnoticed if such device is the only source of emittance reconstruction. In the LHC several of these instruments and techniques are available; wire scanners, synchrotron light monitors, emittance reconstruction from transverse convolved beam sizes extracted from luminosity scans at the LHC collision points and from beam-gas imaging in the vertex detector of the LHCb experiment. Those systems are briefly presented in this paper together with the comparison of the emittances reconstructed by each of them during physics production over the 2016 LHC run.
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MOPAB115	Transverse Beam Phase-Space Measurement Experience at CTF3	quadrupole, optics, collider, linear-collider	393
	D. Gamba, B. Constance, R. Corsini, S. Döbert, L. Malina, T. Persson, J. Roberts, A.P. Rollings, P.K. Skowroński, F. Tecker CERN, Geneva, Switzerland L. Martin JAI, Oxford, United Kingdom A.L. Peirson Serratosa Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	One of the objective of the CLIC Test Facility (CTF3) at CERN is to demonstrate the CLIC Drive Beam Recombination concept. An accurate control of the transverse beam parameters is necessary in order to succeed in preserving the beam quality after the recombination. During the activity of the facility we improved our tools and technique for characterising the transverse phase space of the beam before and after recombination. The common quadrupole scan technique was improved by performing constant-beam-size measurement and it was enriched by a tomographic reconstruction of the phase-space. Moreover studies have been performed in order to estimate and subtract the impact of dispersion on such a measurements. An overview of these techniques will be presented with actual measurements performed over the last year of operations of the facility.
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MOPAB120	Beam Instrumentation for the CERN LINAC4 and PSB Half Sector Test	linac, instrumentation, laser, 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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MOPAB127	A New Method for Emittance Reconstruction Using a Scraper in a Dispersive Region of a Low Energy Storage Ring	simulation, storage-ring, antiproton, closed-orbit	429
	J.R. Hunt, J. Resta-López, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom C. Carli CERN, Geneva, Switzerland J.R. Hunt, J. Resta-López, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Science and Technology Funding Council, UK CERN Beam scraping is a standard method for beam emittance measurements at low energies and will be applied at the Extra Low ENergy Antimatter (ELENA) ring. However, in ELENA, as in many other low energy storage rings, the scraper is located in a position of finite dispersion which poses a unique challenge when reconstructing the emittance from beam intensity data. A new algorithm for ELENA and other machines that use a scraper in a dispersive region has been developed. It combines data obtained by scraping the beam from opposite sides with information on the storage ring lattice. In this contribution, the new algorithm is presented, tested using simulations and compared with alternate methods for emittance reconstruction.
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MOPAB130	Cross-Calibration of the LHC Transverse Beam-Profile Monitors	optics, luminosity, proton, experiment	437
	R. Alemany-Fernández, F. Alessio, A. Alexopoulos, C. Barschel, F.S. Carlier, J.M. Coello de Portugal, M. Ferro-Luzzi, A. Garcia-Tabares, M. Hostettler, O. Karacheban, E.H. Maclean, R. Matev, T. Persson, P.K. Skowroński, R. Tomás, G. Trad, S. Vlachos, B. Würkner CERN, Geneva, Switzerland G.R. Coombs EPFL, Lausanne, Switzerland T.B. Hadavizadeh Oxford University, Physics Department, Oxford, Oxon, United Kingdom M. Hofer TU Vienna, Wien, Austria L. van Riesen-Haupt University of Oxford, Oxford, United Kingdom
	Calibration of a transverse beam profile monitor is of fundamental importance to guarantee the best possible accuracy and reliability of the instrument over time. In LHC the calibration standard for transverse-profile measurements are the wire scanners. Other profile monitors such as beam synchrotron light telescopes and interferometers are calibrated with respect to them. Additional information about single-bunch sizes can be obtained from beam-gas imaging in the LHCb vertex detector, from the transverse convolved beam sizes extracted from luminosity scans at the collision points, and from the evolution of the luminous-region parameters as reconstructed by ATLAS and CMS inner tracker detectors during such scans. For the first time in LHC, a dedicated cross-calibration of all the above-mentioned systems was carried out with beam in 2016. Additionally, dedicated optics measurements were also performed in order to determine with the highest possible accuracy the amplitude function at the interaction points and at the position of the profile monitors. Results of these measurements are presented in this paper.
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MOPAB131	Transverse Emittance Measurements Using LHCb's Beam-Gas Interactions	detector, real-time, experiment, operation	441
	T.B. Hadavizadeh Oxford University, Physics Department, Oxford, Oxon, United Kingdom R. Alemany-Fernández, F. Alessio, C. Barschel, G.R. Coombs, M. Ferro-Luzzi, R. Matev CERN, Geneva, Switzerland
	Measurements of the transverse beam emittance are of great importance at particle accelerators such as the LHC in order to monitor, understand and improve the performance of the machine. A number of profile monitors at the LHC are capable of measuring the transverse emittance from a range of different processes including wire scanners and beam synchrotron light monitors, each having advantages and shortcomings. It is possible additionally to measure the beam profiles using interaction vertices reconstructed in LHCb's vertex locator (Velo). Interactions between colliding beam particles and between beam particles and residual gas nuclei are used to build up a picture of the beam profiles. To guarantee the reliability and quality of the different emittance measurements, a dedicated cross-calibration was performed during a machine development period in October 2016. The results obtained with the LHCb Velo during this cross-calibration are presented here.
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MOPAB132	Beam Size Measurement Using High Aspect Ratio LIGA Apertures in an X-Ray Pinhole Camera	electron, radiation, synchrotron, status	445
	L.M. Bobb, G. Rehm DLS, Oxfordshire, United Kingdom
	For optimal brilliance third generation light sources operate at a low emittance and low coupling. Commonly, transverse beam profile measurements are provided by direct imaging of the electron beam using X-ray pinhole cameras. From these beam size measurements and given knowledge of the lattice parameters the emittance, coupling and energy spread are calculated. Ideally, the pinhole aperture should be formed in an infinitely thin screen. However, due to the penetration of X-rays in the keV spectral range, stacked tungsten blades are often used to form the pinhole aperture. In this arrangement the absolute size of the pinhole aperture is unknown and cannot be directly measured, which affects the spatial resolution of the imaging system. Here we investigate the use of X-ray Lithography, Electroplating and Moulding (commonly known as LIGA) to fabricate high aspect ratio pinhole apertures in a gold screen of approximately 1 mm thickness.
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MOPAB137	Validation of a Novel Emittance Diagnostic Method for Beams with Significant Space Charge	space-charge, focusing, quadrupole, simulation	451
	R.B. Fiorito, C.P. Welsch, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom M.E. Conde, N.R. Neveu, J.F. Power ANL, Argonne, Illinois, USA O. Mete Apsimon Cockcroft Institute, Lancaster University, Lancaster, United Kingdom A.G. Shkvarunets UMD, College Park, Maryland, USA
	Funding: Work supported by the EU under grant agreement 624890, the STFC Cockcroft Institute Core Grant No. ST/G008248/1. Exact knowledge of beam emittance is of central importance for essentially every accelerator. However, there are only few methods to determine it when the beam has significant space charge. We report on our progress to validate a novel diagnostic method that has been proposed to determine the RMS emittance of an electron beam with space charge. This method uses RMS divergence and beam size data measured at a screen placed in a free drift region for selected values of magnetic focusing strength. A novel algorithm is then used to determine the cross correlation term and consequently the RMS emittance of the beam. Simulations, quadrupole scans, phase space tomography and optical diffraction-dielectric foil radiation interferometry are currently being employed to determine and compare the horizontal (x) and vertical (y) emittances of the 14 MeV witness electron beam at Argonne National Laboratory's Wakefield Accelerator. The results of simulations and current measurements are presented and the advantages of the new technique are discussed.
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MOPAB141	Instrumentation and Its Interaction With the Secondary Beam for the Fermilab Muon Campus	ion, experiment, simulation, vacuum	466
	D. Stratakis, B.E. Drendel, M.J. Syphers Fermilab, Batavia, Illinois, USA M.J. Syphers Northern Illinois University, DeKalb, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy. The Fermilab Muon Campus will host the Muon g-2 experiment - a world class experiment dedicated to the search for signals of new physics. Strict demands are placed on the beam diagnostics in order to ensure delivery of high quality beams to the storage ring with minimal losses. In this study, we briefly describe the available secondary beam diagnostics for the Fermilab Muon Campus. Then, with the aid of numerical simulations we detail their interaction with the secondary beam. Finally, we compare our results against theoretical findings.
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MOPAB146	Electron Beam Diagnosis Using K-edge Absorption of Laser-Compton Photons	electron, laser, photon, scattering	473
	Y. Hwang, T. Tajima UCI, Irvine, California, USA C.P.J. Barty, D.J. Gibson, R.A. Marsh LLNL, Livermore, California, USA
	Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. The mean energy, energy spread and divergence of the electron beam can be deduced from laser-Compton scattered X-rays filtered by a material whose K-edge is near the energy of the X-rays. This technique, combined with a spot size measurement of the beam, can be used to measure the emittance of electron bunches, and can be especially useful in LWFA experiments where conventional methods are unavailable. The effects of the electron beam parameters on X-ray absorption images are discussed, along with experimental demonstrations of the technique using the Compact Laser-Compton X-ray Source at LLNL.
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MOPAB150	Imaging the Spatial Modulation of a Relativistic Electron Beam	electron, experiment, scattering, quadrupole	480
	C. Zhang, W.S. Graves, L.E. Malin, J. Spence Arizona State University, Tempe, USA D.B. Cesar, J.M. Maxson, P. Musumeci, A. Urbanowicz UCLA, Los Angeles, USA C. Limborg, E.A. Nanni SLAC, Menlo Park, California, USA
	Funding: Work supported by NSF awards 1632780, 1415583, 1231306 and DOE award de-sc0009914 We describe Bragg diffraction of relativistic electron beams through a patterned Si crystal consisting of alternating thick and thin strips to produce nanometer scale electron density modulations. Multi-slice simulations show that a two-beam situation can be set up where, for a particular thickness of Si, nearly 100% of the electron beam is diffracted. Plans are underway to carry out experiments showing this effect in UCLA's ultrafast electron microscopy lab with 3.5 MeV electrons. We will select either the diffracted beam or the primary beam with a small aperture in the diffraction plane of a magnetic lens, and so record either the dark or bright field magnified image of the strips. Our first goal is to observe the nanopatterned beam at the image plane. We will then investigate various crystal thickness and sample orientations to maximize the contrast in the pattern and explore tuning the period of the modulation through varying magnification.
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MOPAB154	Measurement of Proton Transverse Emittance in the Brookhaven AGS	dipole, injection, flattop, proton	494
	H. Huang, L. Ahrens, C.W. Dawson, C.E. Harper, C. Liu, F. Méot, M.G. Minty, V. Schoefer, S. Tepikian, K. Zeno BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. High luminosity and high polarization in RHIC require good control and measurement of emittance in its injector, the Brookhaven AGS. In the past, the AGS emittance has been measured by using an ion collecting IPM during the whole cycle. The beam profiles from this IPM are distorted by space charge forces at higher energy, which makes the emittance determination very hard. The effect has been measured with IPM measurement at different energies with RF off to mitigate the space charge effect. In addition, helical snake magnets and near integer vertical tune for polarized proton operation distort the lattice in the AGS and introduce large beta beating. For more precise measurements of the emittance, we need turn-by-turn (TBT) measurements near injection and beta function measurements at the IPM. The AGS has also been modeled to get the beta functions at the locations of IPM. A new type of electron collecting IPM has been installed and tested in the AGS with proton beam. The vertical beta functions at the IPM locations have been measured with a local corrector near the IPM. This paper summarizes our current understanding of AGS emittances and plans for the further improvements.
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MOPIK017	Simultaneous Generation of Drive and Witness Beam for Collinear Wakefield Acceleration	wakefield, acceleration, controls, quadrupole	535
	G. Ha POSTECH, Pohang, Kyungbuk, Republic of Korea M.E. Conde, D.S. Doran, W. Gai, J.G. Power ANL, Argonne, Illinois, USA
	Funding: This work is supported by Department of Energy, Office of High Energy Physics, under Contract No. DE-AC02-06CH11357. Generating the drive and witness bunch for collinear wakefield acceleration (CWFA) requires precise control of the longitudinal bunch shape for each bunch as well as the controlling their separation. The emittance exchange (EEX) beamline and a transverse mask can be used to achieve all of these requirements. First, this EEX-based method can independently control the longitudinal bunch shape of each bunches so that the drive bunch is shaped to generate a high transformer ratio while witness bunch is shaped to suppress its energy spread. Second, the timing jitter between the drive and witness bunch poses a serious limitation to the CWFA scheme but the EEX-based method eliminates this since both bunches are generated at the same time and share the exactly same beamline so there are no relative errors. In this paper, we confirm the feasibility of this EEX-based method for simultaneous generation with simulation for CWFA in a dielectric structure.
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MOPIK022	Experimental Investigation of Field-Emission From Silicon Nano-Cone Cathodes	cathode, electron, vacuum, ion	548
	A. Lueangaramwong, C. Buzzard, V. Korampally, O. Mohsen, P. Piot Northern Illinois University, DeKalb, Illinois, USA S. Chattopadhyay Northern Illinois Univerity, DeKalb, Illinois, USA R. Divan Argonne National Laboratory, Argonne, Illinois, USA P. Piot Fermilab, Batavia, Illinois, USA
	Funding: This work is supported by the NSF grant PHY-1535401 with Northern Illinois University Field emission cathode are capable of forming electron beam with extreme brightness via strong-field excitation from applied electrostatic, or electromagnetic (radiofrequency and laser) fields. Our group, in collaboration with the Argonne Center for Nanoscale Material, has recently developed nanocone cathode. The present paper reports on the experimental characterization of these cathodes both configured as a single-cone emitter or as large arrays of tightly-packed emitter. The tests carried in a diode setup are capable of measuring IV characteristic curves and beam distributions.
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MOPIK030	Design of a Beamline From a TR24 Cyclotron for Biological Tissues Irradiation	cyclotron, proton, quadrupole, dipole	564
	E. Bouquerel, T. Adam, G. Heitz, C. Maazouzi, C. Matthieu, M. Pellicioli, M. Rousseau, C. Ruescas, J. Schuler, E.K. Traykov IPHC, Strasbourg Cedex 2, France
	Funding: The PRECy project is supported by the Contrat de Projet Etat-Région (CPER) Alsace Champagne-Ardenne Lorraine. The PRECy project foresees the use of a 16-25 MeV energy proton beam produced by the recently installed TR24 cyclotron, CYRCé, at the Institut Pluridisciplinaire Hubert Curien (IPHC) of Strasbourg for biological tissues irradiation. One of the exit ports of the cyclotron will be used for this application along with a combination magnet. The platform will consist of up to 3 or 5 experimental stations linked to beamlines in a dedicated area next to the cyclotron vault. One of the beamlines will receive proton beams of a few cm diameter at intensities up to 100 nA. The status of the design of this first beam line is presented.
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MOPIK042	Beam-Based Kicker Waveform Measurements Using Long Bunches	kicker, flattop, injection, proton	599
	V. Forte, W. Bartmann, J.C.C.M. Borburgh, M.A. Fraser, L. Sermeus CERN, Geneva, Switzerland
	The increased bunch length demanded by the LHC Injectors Upgrade (LIU) project to mitigate emittance growth from space-charge on the PS injection plateau puts strong constraints on the rise-times of the recombination kickers in the transfer lines between the CERN Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS). A beam-based technique has been developed to validate the waveforms of the recombination kickers. In this paper high-resolution measurements are presented by extracting the intra-bunch deflection along bunches with lengths comparable to or longer than the rise-time of the kicker being probed. The methodology has been successfully applied to the three vertical recombination kickers named BT1. KFA10, BT4. KFA10 and BT2. KFA20, and benchmarked with direct measurements of the kicker field made using a magnetic field probe. This paper describes the beam-based technique, summarises the main characteristics of the measured waveforms, such as rise-time and flat-top ripple, and estimates their impact on beam brightness.
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MOPIK054	Towards the Low Emittance CANDLE Storage Ring	lattice, wiggler, storage-ring, synchrotron	641
	A. Sargsyan, G.A. Amatuni, V. Sahakyan, V.M. Tsakanov, G.S. Zanyan CANDLE SRI, Yerevan, Armenia
	Stimulated by the recent approaches and developments in low emittance lattice design and magnet technology a continuous process of CANDLE storage ring lattice improvement has been launched aiming to keep the project competitive in the field. The main goal of the upgrade program is to bring the beam emittances down to sub-nm level, having the condition of cost and performance efficiency. This paper summarizes the results obtained in the above-mentioned direction. The main design characteristics and linear/nonlinear beam dynamics aspects of the obtained new lattices are presented.
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MOPIK056	On the Ariel Pre-Separator	dipole, target, ion, optics	648
	S. Saminathan, R.A. Baartman TRIUMF, Vancouver, Canada
	Funding: Funded under a contribution agreement with NRC (National Research Council Canada) and Capital funding from CFI (Canada Foundation for Innovation). Two new independent target ion sources with dedicated pre-separators will be built in the ARIEL facility to triple the radioactive ion beam production at TRIUMF. A compact Nier-Johnson type of pre-separator has been designed to achieve a mass resolving power of 300 in order to minimize the undesired radioactive species contaminating the downstream beamlines. It consists of a 112 degree magnetic and a 90 degree toroidal electrostatic dipole with deflection in opposite direction. It also contains electrostatic quadrupole elements in between the dipoles. The electrostatic dipole compensates the energy dispersion of the magnetic dipole. This allows an achromatic mode of operation resulting in a high mass resolving power downstream to the electrostatic deflector even for beams with a high energy spread. We present the result of beam optics calculations for the ARIEL pre-separator.
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MOPIK059	Linear and Nonlinear Optimizations of Combined 7BA-6BA Lattices for the Future Upgrade of SOLEIL	lattice, injection, dipole, sextupole	659
	A. Loulergue, P. Brunelle, H.C. Chao, A. Nadji, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	Previous MBA studies converged to a combination of 7BA and 6BA structures, in terms of the target horizontal emittance of below 300 pm-rad, where the effect of anti-bends, dipole field values, and straight section lengths were investigated. Inspired by the successful lattice designs elsewhere adopting the interleaved sextupole scheme with dispersion bumps originally developed at the ESRF, the 7BA-6BA structures adopting this scheme are studied in details in parallel to those without it. The former aims at the horizontal emittance in the 200-300 pm-rad range with on and off-momentum dynamic acceptances sufficiently large for off-axis injection and good Touschek lifetime. The latter pursues the lower bound of the reachable horizontal emittance with quadrupole and sextupole strengths in the feasible range with maximum dynamic acceptance. The option of non-standard on-axis injection such as displacing the injected beam longitudinally is envisaged for the latter solutions. In both lattices, the numerical search using MOGA-based codes is employed extensively. The studies focus on the impact of linear optics and straight section lengths on the off-momentum and nonlinear properties.
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MOPIK060	Applying MOGA to Search Linear Lattice in Soleil Upgrade Project	lattice, sextupole, synchrotron, quadrupole	662
	H.C. Chao, P. Brunelle, R. Nagaoka SOLEIL, Gif-sur-Yvette, France
	In the community of synchrotron radiation facilities, multi-bend structure becomes the trend of the storage ring design toward lower emittance. For SOLEIL upgrade project, the 7BA-6BA hybrid structure is one of the current options. This paper puts the focus on the 7BA section. There are many degrees of freedom to tweak and many constraints to follow. Here, the idea is to search and build the linear lattice utilizing Multi-Objective Genetic Algorithm (MOGA), which is efficient dealing with higher dimension optimization problems. Within MOGA, subsidiary matchings are performed to ensure certain criteria when the new generation is bred. Delicate designs and manipulations of the objective functions are needed, in order to have a better convergence without being trapped in a local minimum. The results will be shown and discussed.
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MOPIK068	Beam Dynamics Design Parameters for KONUS Lattices	lattice, linac, acceleration, cavity	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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MOPIK070	Notes on Relations between Slice and Projected Beam Parameters	FEL, betatron	689
	V. Balandin, N. Golubeva DESY, Hamburg, Germany
	We consider some aspects of the relations between slice and projected beam parameters.
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MOPIK071	Dispersion and Beam Optic Parameter Measurements in the Transport Line (E-Weg) from DESY II to PETRA III	optics, quadrupole, injection, synchrotron	692
	G.K. Sahoo, K. Balewski, H. Ehrlichmann, J. Keil, R. Wanzenberg DESY, Hamburg, Germany
	The transport line E-Weg extends from the extraction septum in DESY II to the injection septum in PETRA III, and transports electrons at a beam energy of 6.0 GeV. It consists of 3 parts. The first part is in DESY tunnel, the second part is a long drift space in a slanted tube and the third part is in PETRA III tunnel. The vertical plane difference between the tunnels is 1.28 m. The optics was derived from initial values at Transfer Point (UGP) from a previous optics. The total length of the transfer line is about 203 m. Ten screen monitors are used to estimate the profiles of the beam spot for the optics measurements, while 8 BPMs, mostly adjacent to the screens, are used to compare and control the orbits. Two scrapers are installed on either side of the long drift space to trim the beam dimensions in transverse plane. Two FCTs are used to measure the beam current and transfer efficiency. The transverse dispersion and beta functions are measured by extracting the beam from DESY at different energies and analysing the beam profiles at the screen as well as positions at BPMs. The details of such measurements are reported in this paper.
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MOPIK088	Vertical Emittance Reduction in the SSRF Phase II Project	coupling, quadrupole, alignment, sextupole	733
	C.L. Li, B.C. Jiang, Z.B. Li, M.Z. Zhang, Q.L. Zhang, W.Z. Zhang SINAP, Shanghai, People's Republic of China
	The Shanghai Synchrotron Radiation Facility (SSRF) Phase II beamline project (SSRF Phase II) will implement the new lattice with dual-canted insertion devices, superbends and superconducting wiggler. The emittance coupling is one of the most important parameters for the high brightness storage ring light sources. It is often less than 1% in the third-generation storage ring light sources. In this paper, the sensitivity of emittance coupling to magnetic alignment errors in the SSRF Phase II is presented. Sixty skew quadrupole magnets are utilized to correct the emittance coupling with gradient descent algorithm. The emittance coupling obtained in the SSRF Phase II lattice is below 0.3%.
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MOPIK096	Predictability of the Beam Quality During RFQ Voltage Tuning	rfq, simulation, distributed, quadrupole	748
	A. Ponton ESS, Lund, Sweden A.C. France CEA/IRFU, Gif-sur-Yvette, France
	It has previously been demonstrated that certain spatial harmonics of the dipolar and quadrupolar components of the RFQ voltage have stronger effects on the beam quality than others. The study suggested that, during the tuning process to compensate for manufacturing errors, some harmonic contents (other than the first ones) should be minimized. The analysis presented in this paper looks at how we can predict the beam quality knowing the content of each voltage harmonics. We propose also a strategy to minimize the impacts of the voltage errors on the output beam phase space during the tuning phase. A. Ponton, A.C. France, Y.I. Levinsen, O. Piquet, B. Pottin, and E. Sargsyan, Voltage Error Studies in the ESS RFQ, in Proc. 7th International Particle Accelerator Conference (IPAC'16), Busan, Korea, May 2016, paper THPMB039, pp. 3320-3323, ISBN: 978-3-95450-147-2
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MOPIK097	Vertical Dispersion and Betatron Coupling Correction for FCC-ee	quadrupole, sextupole, coupling, collider	752
	S. Aumon, B.J. Holzer CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	The FCC-ee project foresees to build a 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁵ cm^-2s^-1. To reach such performances, an extreme focusing of the beam is required in the interaction regions with a low vertical beta function of 2~mm at the IPs. Moreover, the FCC-ee physics program requires very low emittances never achieved in a collider with 1~nm for ε_x and 2~pm for ε_y, bringing down the coupling ratio to 2/1000. Thus, coupling and vertical dispersion sources have to be controlled carefully. This paper describes the tolerance of the machine to magnet alignment errors as well as the optics correction methods that were implemented, such as the Orbit Dispersion Free Steering, in order to bring the vertical dispersion to reasonable values. The correction of the betatron coupling, being also a very important source of emittance growth, has been integrated to a challenging correction scheme to keep the vertical emittance as low as possible.
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MOPIK103	Operation with Carbon Stripping Foils at ISIS	injection, electron, operation, synchrotron	771
	H.V. Cavanagh, B. Jones STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS facility at the Rutherford Appleton Laboratory is a pulsed neutron and muon source for physical and life science research. Up to 3·10¹³ protons per pulse are accelerated to 800 MeV in the 50 Hz rapid cycling synchrotron that serves two spallation neutron targets. Charge exchange injection of 70 MeV H' ions into the synchrotron takes place over 130 turns. For over 30 years ISIS has used 40×120 mm aluminium oxide stripping foils, produced in-house [1]. Recently, foil preparation and installation processes have been simplified with the use of commercially available 40×60 mm carbon stripping foils. This paper summarises operational experiences with diamond-like-carbon (DLC) and graphene foils. Radiological analysis, atomic force microscope (AFM) imaging of foils and off-line irradiation with a 1.5 keV electron gun are also discussed.
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MOPIK111	Initial Performance Measurements of Multi-GHz Electron Bunch Trains	electron, laser, gun, cathode	795
	D.J. Gibson, R.A. Marsh LLNL, Livermore, California, USA Y. Hwang UCI, Irvine, California, USA
	Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL's compact laser-Compton based x-ray source is currently producing up to 35 keV photons, with the capability to upgrade to 250 keV. Increasing the average brightness of such sources requires increasing the electron beam current. To avoid degradation of the narrow-bandwidth performance of the source, the per-bunch charge shouldn't increase; the effective repetition rate of the electron beams must be raised. It has been proposed* to generate bunch trains of several hundred pulses spaced by the period of X-band RF (~87 ps), which raises questions about beam-loading effects on the energy uniformity of the bunches and wakefield effects degrading the emittance of later bunches, compromising the x-ray quality. As a first test of this concept, we have installed into the electron-generating laser of our system optical pulse-stacking hardware to allow generation of 16-electron-bunch trains. Here we present the current status of our x-ray source, along with initial results using this new multi-bunch train. This includes characterization of collective electron beam energy spread and emittance growth. * D.J. Gibson, et al., IPAC2012.
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MOPIK112	High Average Power Deuteron Beam Dynamics	neutron, target, quadrupole, diagnostics	798
	R.A. Marsh, G.G. Anderson, S.G. Anderson, D.L. Bleuel, M.L. Crank, P. Fitsos, D.J. Gibson, M. Hall, M.S. Johnson, B. Rusnak, J.D. Sain, R. Souza, A. Wiedrick LLNL, Livermore, California, USA
	Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 Lawrence Livermore National Lab (LLNL) is developing an intense, high-brightness fast neutron source to create sub-mm-scale resolution neutron radiographs and images. A pulsed 7MeV, 300μA average-current commercial deuteron accelerator will produce an intense source (10¹¹ n/s/sr at 0 deg) of fast neutrons (10MeV) using a novel neutron target with a small (1.5mm diameter) beam spot size to achieve high resolution. A highly flexible multi-accelerator beamline has been developed allowing for the use of both 4MeV and 7MeV RFQ/DTL deuteron accelerators. TRACE3D has been used to model the beam transport and design the quadrupole lattice and results will be presented including iterated design within beamline mechanical constraints, sensitivities, and multiple use of the magnets. Because of the high power density of such a tightly focused, modest-energy ion beam, intercepting beam diagnostics are extremely challenging, motivating novel concepts and extensions of current techniques to higher average power densities. Full duty factor beamline diagnostics will be discussed including charge, position, emittance via beam-induced fluorescence, and a full power beam dump and Faraday cup.
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MOPIK113	Beam Phase Space Tomography for FXR LIA	space-charge, simulation, solenoid, electron	801
	Y.H. Wu, Y.-J. Chen LLNL, Livermore, California, USA
	Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Knowing the initial beam parameters entering an accelerator or a downstream beamline allows us to select transport tunes optimized for a desired accelerator performance. In this study, we report unfolding LLNL's FXR [1] beam parameters by using the tomography technique [2, 3] to construct the beam phase space along the accelerator's downstream beamline. The unfolded phase spaces from tomography and simulations are consistent.
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MOPIK114	End-to-End Energy Variation Study for Induction Radiography Accelerator	target, beam-transport, solenoid, simulation	804
	Y.H. Wu, Y.-J. Chen LLNL, Livermore, California, USA
	Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Energy variation study for beam transport from the entrance of a conceptual induction radiography accelerator to the x-ray target has been reported previously [1]. In this report, we have extended the study upstream to the injector. To achieve minimum emittance growth and to obtain a desired final beam size, we have developed three optimal tunes. Among them, one optimal tune, capable of supressing beam break-up instability and producing acceptable corkscrew motions, is used to study the energy variation effects on radiography performance. The study shows that ±3% energy variation is acceptable.
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MOPIK115	A Design for 10 GeV, High Peak-Current, Tightly Focused Electron Beams at FACET-II	linac, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK115
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MOPIK118	Model Based Optics Studies in the MEBT Section of SNS	linac, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK118
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MOPVA001	Coherent X-Ray Radiation From Electron Beam Processed by Channeling and Emittance Exchange	electron, photon, radiation, laser	845
	I. Lobach, A.I. Benediktovitch BSU, Minsk, Belarus
	Presented contribution theoretically studies a novel scheme of compact intense x-ray radiation source. In the scheme, longitudinally modulated electron beam emits x-rays by Inverse Compton Scattering (ICS). The setup's feature is the way how longitudinal density modulation in angstrom scale is created. There are three stages of processing of initial beam of relativistic electrons: 1. First, the electrons cross a crystal plate in channeling regime. It is shown that upon leaving the crystal, the electron beam acquires discernible transverse modulation in angstrom scale. It is taken into account that not all electrons are captured in channeling mode and that some of those that do may leave it as they travel through the crystal slab. 2. Further, the beam is transported to Emittance Exchange (EEX) line, in which the direction of modulation is tilted and the beam becomes longitudinally modulated. The scale of modulation remains the same. 3. Finally, intense quasi-coherent x-ray radiation is emitted by ICS. Numerical estimations show that coherent contribution to intensity is considerable for feasible parameters of used beam, components of EEX line and laser producing photons for ICS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA001
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MOPVA010	Setup and Status of an SRF Photoinjector for Energy-Recovery Linac Applications	gun, SRF, laser, cathode	865
	T. Kamps, D. Böhlick, A.B. Büchel, M. Bürger, P. Echevarria, A. Frahm, F. Göbel, S. Heling, A. Jankowiak, S. Keckert, H. Kirschner, G. Klemz, J. Knobloch, G. Kourkafas, J. Kühn, O. Kugeler, A.N. Matveenko, A. Neumann, N. Ohm-Krafft, E. Panofski, F. Pfloksch, S. Rotterdam, M.A.H. Schmeißer, M. Schuster, H. Stein, J. Ullrich, A. Ushakov, J. Völker HZB, Berlin, Germany I. Will MBI, Berlin, Germany
	Funding: The work is funded by the Helmholtz-Association, BMBF, the state of Berlin and HZB. The Superconducting RF (SRF) photoinjector programme for the energy-recovery linac (ERL) test facility BERLinPro sets out to push the brightness and average current limits for ERL electron sources by tackling the main challenges related to beam dynamics of SRF photoinjectors, the incorporation of high quantum efficiency (QE) photocathodes, and suppression of unwanted beam generation. The paper details the experimental layout of the SRF photoinjector and the gun test facility GunLab at Helmholtz-Zentrum Berlin.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA010
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MOPVA018	Resonant Coherent Diffraction Radiation System at ERL Test Accelerator in KEK	cavity, radiation, resonance, experiment	887
	Y. Honda, A. Aryshev, R. Kato, T. Miyajima, T. Obina, M. Shimada, R. Takai, N. Yamamoto KEK, Ibaraki, Japan
	Funding: This work was supported by JSPS KAKENHI Grant Number 16H05991 An Energy Recovery Linac can produce a low emittance and short bunch beam at a high repetition rate. A test accelerator, compact-ERL, has been operating in KEK for development works of technologies related to ERL and CW-Superconducting accelerators. In a special beam operation mode of bunch compression, a short bunch beam of ~150 fs at the repetition rate of CW 1.3 GHz can be realized in the return-loop. One of the promising applications of such a short bunch beam is a high power THz radiation source produced by a coherent radiation. When a charged particle beam passes close to a conductive target, a radiation called diffraction radiation is produced. If the target mirrors form an optical cavity which fundamental frequency matches the repetition frequency of the beam, the radiation resonates in the cavity, resulting in extracting a huge radiation power determined by the loss of the cavity. We plan to perform an experiment of the resonant coherent diffraction mechanism in the return-loop of the compact-ERL to test the feasibility to be a wide band high power THz source. We report the design of the experimental setup to be installed in the summer of 2017.
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MOPVA019	60 pC Bunch Charge Operation of the Compact ERL at KEK	operation, laser, cavity, linac	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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MOPVA026	Effects of Insertion Devices on Stored Electron Beam of High Energy Photon Source	undulator, photon, insertion, brilliance	911
	X.Y. Li, Z. Duan, D. Ji, Y. Jiao, Y.F. Yang IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS) is a 4th generation, 6-Gev, ultralow-emittance, photon source project in China. High brightness hard X-ray beams at the energy particularly above 10kev are provided by insertion devices installed in straight sections of the storage ring. Brightness tuning curves of 14 ID beamlines planned in HEPS first stage are obtained after designing their parameters. However the presence of these insertion devices produce several effects on the beam performances including betatron tunes, betatron amplitude functions, closed orbit, emittance and dynamic aperture etc. It is found that the vertical octupole effect due to the fourteen IDs under the present schemes produce the most significant effect on the vertical dynamic aperture reduction. The ID field error effects on close orbit can be completely compensated by two correctors adjacent the ID at the both side. The horizontal emittance reduces to 36pm.rad due to the damping wiggler effect of IDs with field error after the orbit correction is also obtained.
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MOPVA029	Conceptual Design of a Pre-Booster Ring for the FCC e⁺e⁻ Injector	booster, extraction, damping, injection	917
	O. Etisken, A.K. Çiftçi Ankara University, Faculty of Sciences, Ankara, Turkey Y. Papaphilippou CERN, Geneva, Switzerland
	The FCC-ee injector complex needs to produce and to transport a high-intensity e⁺/e⁻ beam at a fast repetition rate of about 0.1 Hz for topping up the collider at its collision energy. A basic parameter set exists for all the collider energies, assuming a 10 GeV linac operating with a large number of bunches being accumulated in the existing SPS, which serves as pre-accelerator and damping ring before the bunches are transferred to the high-energy booster. The purpose of this study is to provide the conceptual design of an alternative accelerator ring, replacing the SPS in the present scheme. This ring will have injection energy of around 5 GeV and extraction energy of around 20 GeV. Apart from establishing the basic parameters of the ring, the study work will include the optics design and layout, single particle linear and non-linear dynamics optimization, including magnetic and alignment error tolerances. The study will also contain some basic estimation of collective effects and address the issue of synchrotron radiation handling.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA029
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MOPVA031	Low Energy Compact Storage Ring Design for Compton Gamma-Ray Light Source	electron, laser, storage-ring, scattering	921
	Z. Pan, J.M. Byrd, C. Sun LBNL, Berkeley, USA H. Hao, Y.K. Wu FEL/Duke University, Durham, North Carolina, USA W.-H. Huang, C.-X. Tang TUB, Beijing, People's Republic of China
	Gamma-ray sources with high flux and spectral densities are highly demanded by many nuclear experiments. We design a low energy compact storage ring to produce gamma-ray with energy in the range of 4-20 MeV based on Compton backscattering technique. The storage ring energy is 500-800 MeV with the circumference of about 59 m and natural emittance of about 3 nmrad at 500 MeV. In this paper, we present the storage ring lattice design and propose two collision configurations for Compton gamma-ray generation. Intrabeam scattering has been investigated which can increase emittance from 3 nmrad to 6 nmrad horizontally for 500 MeV ring. We also discuss how Compton scattering affects longitudinal and transverse beam dynamics by tracking macro particles using our parallel simulation code. Based on this study, we can further optimize our storage ring lattice design for the higher gamma-ray flux production.
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TUXA1	Towards Diffraction Limited Storage Ring Based Light Sources	storage-ring, lattice, undulator, electron	1203
	L. Liu, H. Westfahl Jr. LNLS, Campinas, Brazil
	Experimental x-ray techniques that benefit from the great increase in brightness and coherent flux provided by the fourth generation of synchrotron light sources, based on recent advances in accelerator design and technology, are widely expanding nowadays. The basic ingredient to higher brightness is a further reduction of the electron beam emittance in storage rings dedicated to light sources. However, to fully explore the potential of these new sources, it is necessary to optimize other variables as well, such as the proper matching of electrons and photons phase-space and the possibility of using new kinds of insertion devices. Equally important is to try new ways to improve the integration between the light source capabilities and the experiment needs. In this work, recent progress of low emittance rings will be reviewed and the efforts to improve transverse coherent flux and source-to-beamline integration at the Brazilian Sirius project will be described.
	Slides TUXA1 [11.984 MB]
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TUYA1	Linac4: From Initial Design to Final Commissioning	linac, quadrupole, proton, 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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUYA1
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TUOBA2	Commissioning of the MYRRHA Low Energy Beam Transport Line and Space Charge Compensation Experiments	rfq, solenoid, proton, injection	1226
	F. Bouly, M.A. Baylac, D. Bondoux LPSC, Grenoble Cedex, France J. Belmans, D. Vandeplassche Studiecentrum voor Kernenergie - Centre d'Étude de l'énergie Nucléaire (SCK•CEN), Mol, Belgium N. Chauvin, F. Gérardin CEA/IRFU, Gif-sur-Yvette, France
	Funding: This work is supported by the European Atomic Energy Community's (EURATOM) H2020 Programme under grant agreement n°662186 (MYRTE project). The MYRRHA project aims at the construction of a new research reactor in Mol (Belgium) to demonstrate the nuclear waste transmutation feasibility with an Accelerator Driven System (ADS). In its subcritical configuration, the MYRRHA facility requires a proton beam with a maximum power of 2.4 MW (600 MeV - 4 mA). Such a continuous wave beam will be delivered by a superconducting linear accelerator (linac) which must fulfil very stringent reliability requirements to ensure the safe ADS operation with a high level of availability. The linac injector will be composed of: a proton source, a low energy beam transport line (LEBT), a 176 MHz RFQ and CH-DTL cavities. The LEBT prototype has been built and is presently installed and operated at LPSC Grenoble (France). An experimental program, to optimise the tuning of the line, the beam transport, and to study the space charge compensation mechanism, is in progress. We here review the main achievements of the LEBT commissioning. Experimental results will be presented and discussed, in particular the influence of the residual gas (type and pressure) on the beam dynamics.
	Slides TUOBA2 [3.929 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUOBA2
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TUZB1	Final Results From the Clic Test Facility (CTF3)	linac, operation, acceleration, 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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUZB1
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TUZB2	Commissioning Status of High Luminosity Collider Rings for SuperKEKB	electron, solenoid, quadrupole, positron	1275
	H. Koiso KEK, Ibaraki, Japan
	SuperKEKB project aims to obtain the world's highest luminosity of 8x10³⁵/cm/s, in order to discover new particle physics beyond the Standard Model. Key technologies for the high luminosity are nano-beam scheme at the collision point and high positron and electron stored current with low emittance, which require the significant upgrade of both the injector and the collider rings. Recently commissioning of the renewal collider rings has been performed without final focus magnets and the Belle II detector (Phase 1). This talk gives results of the Phase 1 commissioning and construction status toward the first beam collisions (Phase 2).
	Slides TUZB2 [64.509 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUZB2
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TUOCB1	Progress in the Design of Beam Optics for FCC-ee Collider Ring*	quadrupole, collider, optics, sextupole	1281
	K. Oide, K. Ohmi KEK, Ibaraki, Japan M. Benedikt, H. Burkhardt, B.J. Holzer, A. Milanese, J. Wenninger, F. Zimmermann CERN, Geneva, Switzerland A.P. Blondel, M. Koratzinos DPNC, Genève, Switzerland A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov BINP SB RAS, Novosibirsk, Russia M. Boscolo INFN/LNF, Frascati (Roma), Italy
	The beam optics for the FCC-ee collider has been updated: (a) the layout is adjusted to a new footprint of FCC-hh, (b) the design around the interaction point is refined considering a number of machine-detecor interface issues, (c) the arc lattice is refined taking realistic magnet designs into account, (d) the β^* and betatron tunes are re-optimized according to recent results of the beam-beam simulations, and more. These changes make the collider design more realistic without performance degradation.
	Slides TUOCB1 [4.891 MB]
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TUPAB005	Investigation of Beam Variation and Emittance Growth Simulation With Both Misalignments and the Beam Jitter for SuperKEKB Injector Linac	linac, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB005
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TUPAB009	Design Study on CEPC Positron Damping Ring and Bunch Compressor	damping, linac, positron, 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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TUPAB014	Preliminary Design of FCC-ee Pre-Injector Complex	linac, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB014
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TUPAB015	Pulsed Beam Tests at the SANAEM RFQ Beamline	rfq, proton, cavity, plasma	1341
	G. Turemen, Y. Akgun, A. Alacakir, I. Kilic, B. Yasatekin TAEK - SANAEM, Ankara, Turkey F. Ahiska EPROM Electronic Project & Microwave Ind. and Trade Ltd. Co., Ankara, Turkey E. Cicek Gazi University, Faculty of Arts and Sciences, Teknikokullar, Ankara, Turkey E. Ergenlik, S. Ogur, E. Sunar, V. Yildiz Bogazici University, Bebek / Istanbul, Turkey G. Unel UCI, Irvine, California, USA
	Funding: Turkish Atomic Energy Authority A proton beamline consisting of an inductively coupled plasma (ICP) source, two solenoid magnets, two steerer magnets and a radio frequency quadrupole (RFQ) is developed at the Turkish Atomic Energy Authority's (TAEA) Saraykoy Nuclear Research and Training Center (SNRTC-SANAEM) in Ankara. In Q4 of the 2016 the RFQ was installed in the beamline. The high power tests of the RF power supply and the RF transmission line were done successfully. The high power RF conditioning of the RFQ was performed recently. The 13.56 MHz ICP source was tested in two different conditions, CW and pulsed. The characterization of the proton beam was done with ACCTs, Faraday cups and a pepper-pot emittance meter. Beam transverse emittance was measured in between the two solenoids of the LEBT. The measured beam is then reconstructed at the entrance of the RFQ by using computer simulations to determine the optimum solenoid currents for acceptance matching of the beam. This paper will introduce the pulsed beam test results at the SANAEM RFQ beamline. In addition, the high power RF conditioning of the RFQ will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB015
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TUPAB020	AREAL 50 MeV Electron Accelerator Project for THz and Middle IR FEL	radiation, electron, gun, FEL	1355
	G.A. Amatuni, Z.G. Amirkhanyan, V.S. Avagyan, A. Azatyan, V. Danielyan, H. Davtyan, S.G. Dekhtiarov, N. Ghazaryan, B. Grigoryan, L. Hakobyan, M. Ivanyan, V.G. Khachatryan, E.M. Laziev, T. Markosyan, N. Martirosyan, Sh.A. Mehrabyan, T. Melkumyan, T.H. Mkrtchyan, V.H. Petrosyan, V. Sahakyan, A. Sargsyan, A.S. Simonyan, A.V. Tsakanian, V.M. Tsakanov, A. Vardanyan, Ta.S. Vardanyan, T.L. Vardanyan, V. V. Vardanyan, A.S. Yeremyan, G.S. Zanyan CANDLE SRI, Yerevan, Armenia P.S. Manukyan SEUA, Yerevan, Armenia A.V. Tsakanian HZB, Berlin, Germany
	Advanced Research Electron Accelerator Laboratory (AREAL) is an electron accelerator project based on photo cathode RF gun. First phase of the facility is a 5 MeV energy RF photogun, which is currently under operation. The facility development implies energy upgrade to 50 MeV with further delivery of the electron beam to the undulator sections for Free Electron Laser and coherent undulator radiation generation in MIR and THz frequency ranges respectively. In this report the design study of AREAL 50 MeV facility main systems along with the beam dynamics and characteristics of expected radiation are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB020
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TUPAB028	Measuring the Spectral Response of Cs-K-Sb Photocathodes for BERLinPro	SRF, cathode, electron, linac	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB028
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TUPAB033	Design of a Stripline Kicker for the ELBE Accelerator	kicker, electron, neutron, laser	1393
	Ch. Schneider, A. Arnold, J. Hauser, P. Michel, G.S. Staats HZDR, Dresden, Germany
	ELBE is a linac based cw electron accelerator serving different secondary beams one at a time. Depending on the user demand the bunch repetition rate may vary from single pulse up to 13 MHz. For the future different end stations should be served simultaneously, hence specific bunch patterns have to be kicked to other beam-lines. To use e.g. one bunch out of the bunch train very short kicking durations have to be realized. The variability of the bunch pattern and the frequency resp. switching time are one of the main arguments for a stripline-kicker combined with HV-switches as basic concept. A nearly homogenous field in the kicker has to be realized for uniform deflection of the electron bunch and emittance grow of the bunch has to be kept as low as possible. Furthermore the fast switching ability of the kicker demands for a fast decay of the HV-pulse resp. its reflections in the structure implying a specific design of the kicker elements. For this reason a design with two tapered active electrodes and two ground fenders was optimized in time and frequency domain with the software package CST. Additionally a first prototype was manufactured for laboratory and first beam-line tests.
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TUPAB035	Field Quality of 1.5 m Long Conduction Cooled Superconducting Undulator Coils with 20 mm Period Length	undulator, multipole, photon, synchrotron	1395
	S. Casalbuoni, N. Glamann, A.W. Grau, T. Holubek, D. Saez de Jauregui KIT, Eggenstein-Leopoldshafen, Germany C. Boffo, T.A. Gerhard, M. Turenne, W. Walter Babcock Noell GmbH, Wuerzburg, Germany
	The Institute for Beam Physics and Technology (IBPT) at the Karlsruhe Institute of Technology (KIT) and the industrial partner Babcock Noell GmbH (BNG) are col-laborating since 2007 on the development of superconducting undulators both for ANKA and low emittance light sources. The first full length device with 15 mm period length has been successfully tested in the ANKA storage ring for one year. The next superconducting undulator has 20 mm period length (SCU20) and is also planned to be installed in the accelerator test facility and synchrotron light source ANKA. The SCU20 1.5 m long coils have been characterized in a conduction cooled horizontal test facility developed at KIT IBPT. Here we present the local magnetic field and field integral measurements, as well as their analysis including the expected photon spectrum. S. Casalbuoni et al., Characterization and long term operation of a novel superconducting undulator with 15 mm period length in a synchrotron light source, Phys. Rev. ST Accel. Beams, vol. 19, p.110702, Nov. 2016.
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TUPAB047	Design of a Low Emittance High Current Photocathode RF Gun for the IPM Linear Accelerator	cavity, gun, focusing, simulation	1431
	M. Dayyani Kelisani, H. Shaker CERN, Geneva, Switzerland H. Shaker IPM, Tehran, Iran
	The IPM accelerator project is developing a 50 MeV linear accelerator as an injector for a terahertz source or an IR FEL. The design specifications require a laser driven photocathode located in one end of a high gradient RF cavity operated at 3 GHz frequency and a solenoid channel for the beam transport. In this work, we report on the RF design of an special photocathode RF gun and its associated focusing channel for the emittance compensation process along the whole injector.
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TUPAB055	Development of compact magnetic field measurement system available for in-vacuum undulators	undulator, brightness, vacuum, photon	1449
	M. Adachi, R. Kato, T. Shioya, K. Tsuchiya KEK, Ibaraki, Japan
	A low-emittance 3-GeV KEK-LS* ring has been designed at KEK. KEK-LS's undulators can produce extremely high brightness light ranging from VUV to X-ray. Brightness of undulator light strongly depends on the phase error of its periodic magnetic field. Then a precise magnetic field adjustment is required in order to prevent the reduction of the brightness performance. Generally, the adjustment is performed by the conventional field measurement system equipped with hole-probes on a huge stone table. But, for the in-vacuum undulator, the measurement must be performed without the vacuum chamber. The additional phase error caused by reattaching the chamber is not negligible for the low emittance rings. Therefore, some groups have developed measurement systems available for the direct field measurement inside the chamber,. We have started to develop a compact measurement system. Our system is compacted and stabilized by utilizing the rigid metal beam of the undulator frame instead of the stone table. In the conference, we will report the detail of the system and the present status of the development. KEK-LS HP, http://kekls.kek.jp/ T. Tanaka, et al., Physical Review ST-AB, vol.12, p.120702 (2009). * M. Musardo, et al., Proceedings of IPAC2015, Richmond, VA, USA, p.1693 (2015).
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TUPAB065	The Progress of HEPS Booster Design	booster, lattice, storage-ring, injection	1472
	Y.M. Peng, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, S.K. Tian, G. Xu IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS), a kilometre-scale, ultralow-emittance storage ring light source, is to be built in Beijing, China. For HEPS, a full energy booster synchrotron operating at a frequency of 2Hz is considered. In this paper, we will report the progress of the lattice design and physics studies on HEPS booster, containing the injection consideration, ramping process, error studies, and so on.
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TUPAB074	Measurements of Thermal Emittance for Cesium Telluride Photocathodes in an L-Band RF Gun	laser, gun, electron, cathode	1491
	L.M. Zheng, W. Gai, C.-X. Tang TUB, Beijing, People's Republic of China W. Gai, C.-J. Jing, W. Liu, N.R. Neveu, J.G. Power, J.H. Shao, E.E. Wisniewski ANL, Argonne, Illinois, USA W. Liu Euclid TechLabs, LLC, Solon, Ohio, USA
	The thermal emittance is a major contributor to the final emittance of an electron beam in a photocathode RF gun. In this paper we present measurement results of thermal emittance for the cesium telluride photocathode at the Argonne Wakefield Accelerator (AWA) facility using the quadrupole scan method. Measurements of the thermal emittance vs. the laser spot size are presented.
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TUPAB076	Design of an X-Band Photocathode for Tsinghua Thomson Scattering X-Ray Source	gun, laser, solenoid, cathode	1497
	L.Y. Zhou, H.B. Chen, Y.-C. Du, W. Gai, W.-H. Huang, J. Shi, C.-X. Tang, D. Wang, Z. Zhang, Z. Zhou TUB, Beijing, People's Republic of China
	Compared with S-band and C-band accelerating structures, X-band structures can run at a higher accelerating gradient and are more compact in size. In order to obtain higher electron energy in a limited space, a new X-band photo-injector operating at 11.424GHz has been designed at the Accelerator Laboratory of Tsinghua University. The structural design of the X-band photo-cathode RF gun and the accelerating structures as well as the beam dynamics simulation are presented in this paper, followed by the optimization of the structure based on the dispersed optimization experiment method(DOE). The results show that the design satisfies the working requirements with a small space occupied and a high beam quality.
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TUPAB077	A Combined THz/X-ray Source Based on Brake-applied Velocity Bunching and Magnetic Compression	electron, radiation, bunching, laser	1500
	R. Huang, Z.G. He, Q.K. Jia, B. Li, W.W. Li, L. Wang, S.C. Zhang USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Work supported by Chinese Universities Scientific Fund under Contracts WK2310000063 and WK2310000047 Ultrashort electron beam can be realized by the process of velocity bunching and magnetic compression. Velocity bunching technique is able to compress the bunch at relatively low energy, which presents peculiar challenges when approaching a very high current and a low transverse emittance in photoinjectors. A brake-applied velocity bunching scheme was proposed, so that the transverse emittance of the beam could be almost compensated even if the compression factor was extremely high. By adding a magnetic compressor, one could obtain a shorter beam and achieve the coherent synchrotron radiation in THz range. Meanwhile, when making the final compressed beam collide with the laser, one could acquire high energy X-ray pulses. This opens the possibility for some interesting combinations of pump-and-probe experiments.
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TUPAB083	Commissioning Experience and Beam Optimization for DCLS Linac	linac, gun, 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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TUPAB086	Design Study of a High-Intensity, Low-Energy Electron Gun	gun, electron, simulation, FEL	1517
	Q. Zhang, K. Fan, T. Hu, K.F. Liu, Z.Y. Mei HUST, Wuhan, People's Republic of China
	An independently-tunable-cells thermionic RF gun (ITC-RF gun) is adopted in a compact FEL-THz facility due to its compactness, low-cost and high intensity. An electron gun is required to generate maximum beam current of 3.2 A at low energy of 15keV for the ITC-RF gun, which creates difficulties for the design of electron gun because of the strong space charge effect. A double-anode gridded gun structure is adopted that controls the beam current easily while maintains the energy dispersion less than 0.5%, with high perveance and high compression ratio. CST code has been used extensively for design optimization, which includes electrode shape, influences of grid, installation errors. A measurement scheme is also proposed for key parameters verification. Beam current, emittance and energy dispersion can be measured.
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TUPAB094	Emittance Improvements in the MAX IV Photocathode Injector	linac, 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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TUPAB095	The New MAX IV Gun Test Stand	gun, laser, cathode, operation	1537
	J. Andersson, F. Curbis, M. Kotur, D. Kumbaro, F. Lindau, E. Mansten, S. Thorin, S. Werin MAX IV Laboratory, Lund University, Lund, Sweden
	The gun test stand from MAX-Lab has been upgraded and moved to a new facility at the MAX IV Laboratory. The new test stand will reuse parts of the equipment from the old test stand but a number of improvements to the setup are be made. In this paper we report on the design of the new gun test stand, research plans in the near future as well as planned and possible future research topics.
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TUPAB096	Pulse Shaping at the MAX IV Photoelectron Gun Laser	laser, gun, electron, cathode	1541
	M. Kotur, J. Andersson, M. Brandin, F. Curbis, L. Isaksson, D. Kumbaro, F. Lindau, E. Mansten, D. Olsson, R. Svärd, S. Thorin, S. Werin MAX IV Laboratory, Lund University, Lund, Sweden J. Björklund Svensson Lund University, Lund, Sweden
	A motivation for the development of a versatile, programmable source of shaped picosecond pulses for use in photocathode electron gun preinjectors is presented. We present the experimental setup for arbitrary longitudinal pusle shaping of the MAX IV photocathode gun laser. The setup consists of a grating-based Fourier-domain shaper capable of stretching the pulses directly in the UV domain. Preliminary results are presented and discussed.
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TUPAB110	Possible Limits of Plasma Linear Colliders	plasma, electron, scattering, collider	1576
	F. Zimmermann CERN, Geneva, Switzerland
	Plasma linear colliders have been proposed as next or next-next generation energy-frontier machines for high-energy physics. I investigate possible fundamental limits on energy and luminosity of such type of colliders, considering acceleration, multiple scattering off plasma ions, intrabeam scattering, bremsstrahlung, and betatron radiation. The question of energy efficiency will also be addressed.
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TUPAB111	Energy Distribution and Work Function Measurements for Metal Photocathodes with Measured Levels of Surface Roughness	electron, FEL, detector, plasma	1580
	L.B. Jones, T.S. Beaver, B.L. Militsyn, T.C.Q. Noakes, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S. Mistry STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom S. Mistry Loughborough University, Leicestershre, United Kingdom
	Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 312453. The minimum achievable emittance in an electron accelerator depends strongly on the intrinsic emittance of the photocathode electron source which is measureable as the mean longitudinal and transverse energy spreads in the photoemitted electrons. Reducing emittance in an accelerator driving a Free Electron Laser (FEL) delivers significant reduction in the saturation length for an x-ray FEL, reducing machine cost and increasing x-ray beam brightness. There are many parameters which affect the intrinsic emittance of a photocathode. Surface roughness is a significant factor, and consequently the development of techniques to manufacture low roughness photocathodes with optimum emission properties is a priority for the electron source community. In this work, we present transverse energy distribution and work function measurements made using our TESS facility* for electrons emitted from copper and molybdenum photocathodes with differing levels of measured surface roughness. * Proc. FEL '06, THPPH013, 583-586 ** Proc. FEL '13, TUPPS033, 290-293
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TUPAB126	Multi-objective Genetic Optimization of Single Shot Ultrafast Electron Diffraction Beamlines	gun, electron, cathode, cavity	1615
	C.M. Gulliford, A.C. Bartnik, I.V. Bazarov Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.M. Maxson UCLA, Los Angeles, California, USA
	We present the results of multi-objective genetic algorithm optimizations of two single-shot ultrafast electron diffraction (UED) beam lines. The first is based on a 225 kV dc gun featuring a novel cryocooled photocathode system and buncher cavity. The second uses a 100 MV/m 1.6 cell normal conducting rf (NCRF) gun, as well as a 9 cell 2 Pi/3 bunching cavity placed between two solenoids. Optimizations of the transverse projected emittance as a function of bunch charge are presented and discussed in terms of the scaling laws derived in the charge saturation limit. Additionally, optimization of the transverse coherence length as a function of final rms bunch length at the sample location have been performed. These results demonstrate the viability of the approaches taken for both beamlines studied as well as the use of using genetic algorithms in the design and operation of UED beamlines.
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Paper

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MOXAA1

Commissioning of the European XFEL Accelerator

linac, operation, electron, undulator

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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MOYAA1

Approaching the Nominal Performance at the LHC

luminosity, operation, experiment, injection

13

J. Wenninger
CERN, Geneva, Switzerland

In 2015 the Large Hadron Collider (LHC) restarted for Run 2 after an almost two year long shutdown to consolidate the machine for operation at nominal beam energy. Following a month of recommissioning and training of the magnet system, the LHC operated for the first time at an energy of 6.5 TeV. The aim of this first year was to master operation at the higher energy and with beams of 25 ns spacing. In 2016 the performance could be pushed based on the experience of 2015, culminating with a luminosity 40% above the design value of 10³⁴ cm^-2s⁻¹. The status of the machine operation, performance and prospects for the rest of Run 2 and Run 3 will be discussed.

Slides MOYAA1 [4.639 MB]

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MOZA1

Electron Cloud Effects at the LHC and LHC Injectors

electron, operation, simulation, dipole

30

G. Rumolo, H. Bartosik, E. Belli, P. Dijkstal, G. Iadarola, K.S.B. Li, L. Mether, A. Romano, M. Schenk, F. Zimmermann
CERN, Geneva, Switzerland
E. Belli
University of Rome La Sapienza, Rome, Italy
P. Dijkstal
TU Darmstadt, Darmstadt, Germany
M. Schenk
EPFL, Lausanne, Switzerland

Electron cloud effects are one of the main limitations of the performance of the LHC and its injectors. Enormous progress has been done in the simulation of the electron cloud build-up and of the effects on beam stability while mitigation measures have been identified and implemented (scrubbing, low secondary electron yield coatings, etc.). The above has allowed reaching nominal beam parameters in the LHC during Run 2. A review of the studies and results obtained and the strategy and expected performance for the High Luminosity operation of the LHC will be presented.

Slides MOZA1 [12.855 MB]

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MOPAB014

Generating Low Beta Regions With Quadrupoles for Final Muon Cooling

quadrupole, simulation, collider, betatron

107

J.G. Acosta, L.M. Cremaldi, T.L. Hart, S.J. Oliveros, D.J. Summers
UMiss, University, Mississippi, USA
D.V. Neuffer
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359
Muon beams and colliders are rich sources of new physics, if muons can be cooled. A normalized rms transverse muon emittance of 280 microns has been achieved in simulation with short solenoids and a betatron function of 3 cm. Here we use ICOOL, G4beamline, and MAD-X to explore using a 400 MeV/c muon beam and strong focusing quadrupoles to approach a normalized transverse emittance of 100 microns and finish 6D muon cooling. The low beta regions produced by the quadrupoles are occupied by dense, low Z absorbers, such as lithium hydride or beryllium, that cool the beam. Equilibrium transverse emittance is linearly proportional to the beta function. Reverse emittance exchange with septa and/or wedges is then used to decrease transverse emittance from 100 to 25 microns at the expense of longitudinal emittance for a high energy lepton collider. Work remains to be done on chromaticity correction.

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MOPAB016

Beam Diagnostic and Control Systems for AREAL 50 MeV Linac

controls, electron, diagnostics, linac

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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MOPAB023

ESS Emittance Measurements at INFN CATANIA

ion, ion-source, simulation, proton

123

O. Tuske, P. Daniel-Thomas, J.F. Denis, Y. Gauthier, T.J. Joannem, N. Misiara, V. Nadot, G. Perreu, F. Senée, V. Silva
CEA/IRFU, Gif-sur-Yvette, France
L. Celona, L. Neri
INFN/LNS, Catania, Italy
B. Cheymol, T.J. Shea
ESS, Lund, Sweden
I. Chu, M. Monteremand
CEA LITEN, CEA Grenoble, Grenoble, France
Ø. Midttun
University of Bergen, Bergen, Norway
T.V. Vacher
CEA/DSM/IRFU, France

Beam characteristics at low energy are an absolute necessity for an acceptable injection in the next stage of a linear accelerator, and are also necessary to reduce beam loss and radiation inside the machine. CEA is taking part of ESS linac construction, by designing Emittance Measurement Units (EMU) for the Low Energy Beam Transport (LEBT). The EMU are designed to qualify the proton beam produced by the INFN Catania ion source. This measurement has been decided to be time resolved, allowing to follow the beam emittance reduction, during the pulse length. A 1Mhz acquisition board controlled by EPICS save raw datas to an archiver in order to be able to post process the measurements for time resolution. The design corresponds to an Allison's scanner, using entrance and exit slits, electrostatic plates and a faraday cup. The beamstopper protects the device and can be removable to fit to beam power. It has been manufactured by the CEA/LITEN with copper tungsten HIP technique. This article report the first measurements on the ESS injector at INFN CATANIA.

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MOPAB041

Quadrupole Scan Measurements in the Beam Transport Line between DESY II and PETRA III

quadrupole, focusing, synchrotron, beam-transport

174

J. Keil, H. Ehrlichmann, G.K. Sahoo, R. Wanzenberg
DESY, Hamburg, Germany

PETRA III is a 6 GeV third generation synchrotron light source in Hamburg, Germany. The storage ring is operated with a typical beam current of 100 mA and is running in top-up mode. The beam delivered to PETRA III is accelerated by a fast cycling booster synchrotron (DESY II), extracted in a 203 m long beam transport line (E-Weg) and injected afterwards into PETRA III. In the framework of PETRA IV upgrade scenarios the potential for decreasing the extracted emittance from DESY II has been investigated which can be achieved by lowering the extraction energy to 5 GeV and increasing the focusing in DESY II. In addition measuring the emittance of the extracted beam from DESY II and the optics in the beam transport line can help to better understand and improve the injection efficiency of PETRA III. By changing the quadrupole strength and measuring the beam size downstream on a screen monitor in the E-Weg the emittance of DESY II and the Twiss functions at the quadrupole in the E-Weg have been determined. Measurements at different energies and tunes of DESY II will be shown and compared with calculations.

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MOPAB042

Two-Dimensional Synchrotron Radiation Interferometry at PETRA III

synchrotron, radiation, synchrotron-radiation, operation

177

A.I. Novokshonov, A. Potylitsyn
TPU, Tomsk, Russia
G. Kube
DESY, Hamburg, Germany

Synchrotron radiation interferometry is widely used at modern 3rd generation light sources in order to measure transverse electron beam sizes. The technique is based on probing of the spatial coherency of synchrotron radiation in the visible spectral region. The light source PETRA III at DESY (Hamburg, Germany) is using this type of interferometer since several years in order to resolve vertical emittances of about 10 pm.rad. In order to overcome some inherent disadvantages in this setup, a new optical diagnostics beamline was recently commissioned with a two-dimensional interferometer, thus allowing to measure beam sizes in both transverse planes simultaneously. This contribution summarizes the status of the interferometer with first operational experience and describes systematical studies concerning the stability and possibilities to increase the sensitivity on small beam sizes using an intensity imbalance technique.

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MOPAB047

Electron Beam Phase Space Tomography at the European XFEL Injector

electron, quadrupole, FEL, optics

196

M. Scholz, B. Beutner
DESY, Hamburg, Germany

The FEL process is determined by the 6D phase space distribution of relativistic electron bunches. Experimental reconstructions of these distributions are therefore a step foreward to understand the beam dynamics and to optimize FEL operation. The reconstructions of the transverse phase spaces can be acieved with tomographic methods. In the injector of the European XFEL, measurements for the reconstruction of the phase spaces were carried out using phase advance scans with multiple quadrupoles. The beam sizes were kept optimized at the measurement screen. A transversely deflecting cavity (TDS) was used to streak the beam vertically. That allows to do longitudinally slice resolved measurements of the horizontal phase space. The horizontal streak required for the slice measurements in the vertical plane was achieved with a correlated linear energy spread and dispersion. In this paper, we present measurement results showing longitudinal slice resolved reconstructions of the transverse phase spaces taken in the European XFEL injector.

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MOPAB051

Progress in FLASH Optics Consolidation

optics, undulator, gun, laser

211

J. Zemella, M. Vogt
DESY, Hamburg, Germany

FLASH is the superconducting soft X-ray Free Electron Laser in Hamburg at DESY, Germany. A precise knowledge of the beam optics is a key aspect of the operation of a SASE FEL. A campaign of optics consolidation has started in 2013 when the second beam line FLASH2 was installed downstream of the FLASH linac. We give an update on progress of this effort and on recent results.

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MOPAB052

A Transverse Deflection Structure with Dielectric-Lined Waveguides in the Sub-THz Regime

electron, simulation, impedance, laser

215

F. Lemery
University of Hamburg, Hamburg, Germany
R.W. Aßmann, K. Flöttmann, T. Vinatier
DESY, Hamburg, Germany

Longitudinal bunch measurements are typically done with rf-powered transverse deflection structures with operating frequencies 1-12~GHz. We explore the use of mm-scale, THz-driven, dielectric-lined cylindrical waveguides as transverse deflectors by driving the fundamental deflecting mode of the structure, the HEM₁₁. We give a brief overview of the physics, history, and provide an example with a 5~MeV beam using {\sc astra} and {\sc CST-MWS}.
This work was supported by the European Research Council (ERC) under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant agreement no. 609920

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MOPAB064

Photoinjector Emittance Measurement at STAR

gun, electron, solenoid, simulation

257

A. Bacci, C. Curatolo, I. Drebot, L. Serafini, V. Torri
Istituto Nazionale di Fisica Nucleare, Milano, Italy
R.G. Agostino, R. Barberi, V. Formoso, M. Ghedini, F. Martire, C. Pace
UNICAL, Arcavacata di Rende, Italy
D. Alesini, M. Bellaveglia, J.J. Beltrano, F.G. Bisesto, G. Borgese, B. Buonomo, G. Di Pirro, G. Di Raddo, A. Esposito, A. Gallo, A. Ghigo, F. Iungo, A. Papa, L. Pellegrino, A. Stella, C. Vaccarezza, S. Vescovi
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
G. D'Auria, A. Fabris, M. Marazzi
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
V. Petrillo
Universita' degli Studi di Milano, Milano, Italy
A. Policicchio
UniCal & INFN CS, Arcavacata di Rende (CS), Italy
E. Puppin
Politecnico/Milano, Milano, Italy
M. Rossetti Conti
Universita' degli Studi di Milano & INFN, Milano, Italy

STAR is an advanced Thomson source of monochromatic and tunable, ps-long, polarised X-ray beams in the 40-140 keV range. The commissioning has started at the Univ. of Calabria (Italy). The light source is driven by a high-brightness, low-emittance electron beam produced in a LINAC allowing for the source tunability and spectral density. This note reports on an emittance measurement schema based on the insertion of a slit mask in the vacuum chamber dedicated to the photocathode laser entrance. Results of the simulation of the measurement technique are reported, and the use of the data for the optimisation of the accelerator performance are detailed. The experimental setup and the application developed in EPICS for image recording and analysis are also described.

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MOPAB107

A Method for Determining the Roll Angle of the CLIC Accelerating Structures From the Beam Shape Downstream of the Structure

octupole, collider, simulation, experiment

368

J. Ögren, V.G. Ziemann
Uppsala University, Uppsala, Sweden
W. Farabolini
CEA/DSM/IRFU, France

The Compact Linear Collider (CLIC) accelerating structures have a four-fold symmetry from the radial waveguides for damping higher order modes. This symmetry allows for an octupole component of the rf fields to co-propagate with the main accelerating field. The effect of this octupole mode has been observed at the CLIC test facility 3. In CLIC the accelerating structures are mounted together on a moveable girders. There are four vertical and four horizontal actuators on the girder, which allows for 5D control in a limited range and for instance we can roll the girder. By observing the beam shape perturbed by the octupole field on a screen downstream from the structure we can determine the roll angle and thus align the structure azimuthally. Here we discuss a possible method and show some preliminary results.

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MOPAB109

Operational Experience with Luminosity Scans for Beam Size Estimation in 2016 LHC Proton Physics Operation

luminosity, operation, proton, simulation

374

M. Hostettler
LHEP, Bern, Switzerland
K. Fuchsberger, G. Papotti
CERN, Geneva, Switzerland

Luminosity scans were regularly performed at the CERN Large Hadron Collider (LHC) as of 2015 as a complementary method for measuring the beam size. The CMS experiment provides bunch-by-bunch luminosities at sufficient rates to allow evaluation of bunch-by-bunch beam sizes, and the scans are performed in the horizontal and vertical plane separately. Closed orbit differences between bunches can also be derived by this analysis. During 2016 LHC operation, these scans were also done in an automated manner on a regular basis, and the analysis was improved to significantly reduce the systematic uncertainty, especially in the crossing plane. This contribution first highlights the recent improvements to the analysis and elaborates on their impact. The measured beam sizes during 2016 proton physics operation are then shown and compared to measurements from synchrotron light telescopes and estimates based on the absolute luminosities of the LHC experiments.

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MOPAB110

Comparison of Transverse Emittance Measurements in the LHC

luminosity, experiment, detector, operation

377

M. Hostettler, R. Alemany-Fernández, F. Alessio, M. Ferro-Luzzi, K. Fuchsberger, G. Iadarola, R. Matev, S. Papadopoulou, Y. Papaphilippou, G. Papotti, G. Trad
CERN, Geneva, Switzerland
F. Antoniou
The University of Liverpool, Liverpool, United Kingdom
G.R. Coombs
University of Glasgow, Glasgow, United Kingdom
T.B. Hadavizadeh
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

Transverse emittance measurement in a collider is of crucial importance for understanding beam dynamics observations and evaluating the machine performance. Devices measuring the beam emittance face the challenge of dealing with considerable systematic errors that can compromise the quality of the measurement. Having different instruments or techniques that provide beam size estimations in order to compare the outcome and give an unbiased value of the emittance is very important in a collider. The comparison of the different results is as well very useful to identify possible problems in a given equipment which could remain unnoticed if such device is the only source of emittance reconstruction. In the LHC several of these instruments and techniques are available; wire scanners, synchrotron light monitors, emittance reconstruction from transverse convolved beam sizes extracted from luminosity scans at the LHC collision points and from beam-gas imaging in the vertex detector of the LHCb experiment. Those systems are briefly presented in this paper together with the comparison of the emittances reconstructed by each of them during physics production over the 2016 LHC run.

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MOPAB115

Transverse Beam Phase-Space Measurement Experience at CTF3

quadrupole, optics, collider, linear-collider

393

D. Gamba, B. Constance, R. Corsini, S. Döbert, L. Malina, T. Persson, J. Roberts, A.P. Rollings, P.K. Skowroński, F. Tecker
CERN, Geneva, Switzerland
L. Martin
JAI, Oxford, United Kingdom
A.L. Peirson Serratosa
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

One of the objective of the CLIC Test Facility (CTF3) at CERN is to demonstrate the CLIC Drive Beam Recombination concept. An accurate control of the transverse beam parameters is necessary in order to succeed in preserving the beam quality after the recombination. During the activity of the facility we improved our tools and technique for characterising the transverse phase space of the beam before and after recombination. The common quadrupole scan technique was improved by performing constant-beam-size measurement and it was enriched by a tomographic reconstruction of the phase-space. Moreover studies have been performed in order to estimate and subtract the impact of dispersion on such a measurements. An overview of these techniques will be presented with actual measurements performed over the last year of operations of the facility.

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MOPAB120

Beam Instrumentation for the CERN LINAC4 and PSB Half Sector Test

linac, instrumentation, laser, 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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MOPAB127

A New Method for Emittance Reconstruction Using a Scraper in a Dispersive Region of a Low Energy Storage Ring

simulation, storage-ring, antiproton, closed-orbit

429

J.R. Hunt, J. Resta-López, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
C. Carli
CERN, Geneva, Switzerland
J.R. Hunt, J. Resta-López, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Science and Technology Funding Council, UK CERN
Beam scraping is a standard method for beam emittance measurements at low energies and will be applied at the Extra Low ENergy Antimatter (ELENA) ring. However, in ELENA, as in many other low energy storage rings, the scraper is located in a position of finite dispersion which poses a unique challenge when reconstructing the emittance from beam intensity data. A new algorithm for ELENA and other machines that use a scraper in a dispersive region has been developed. It combines data obtained by scraping the beam from opposite sides with information on the storage ring lattice. In this contribution, the new algorithm is presented, tested using simulations and compared with alternate methods for emittance reconstruction.

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MOPAB130

Cross-Calibration of the LHC Transverse Beam-Profile Monitors

optics, luminosity, proton, experiment

437

R. Alemany-Fernández, F. Alessio, A. Alexopoulos, C. Barschel, F.S. Carlier, J.M. Coello de Portugal, M. Ferro-Luzzi, A. Garcia-Tabares, M. Hostettler, O. Karacheban, E.H. Maclean, R. Matev, T. Persson, P.K. Skowroński, R. Tomás, G. Trad, S. Vlachos, B. Würkner
CERN, Geneva, Switzerland
G.R. Coombs
EPFL, Lausanne, Switzerland
T.B. Hadavizadeh
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
M. Hofer
TU Vienna, Wien, Austria
L. van Riesen-Haupt
University of Oxford, Oxford, United Kingdom

Calibration of a transverse beam profile monitor is of fundamental importance to guarantee the best possible accuracy and reliability of the instrument over time. In LHC the calibration standard for transverse-profile measurements are the wire scanners. Other profile monitors such as beam synchrotron light telescopes and interferometers are calibrated with respect to them. Additional information about single-bunch sizes can be obtained from beam-gas imaging in the LHCb vertex detector, from the transverse convolved beam sizes extracted from luminosity scans at the collision points, and from the evolution of the luminous-region parameters as reconstructed by ATLAS and CMS inner tracker detectors during such scans. For the first time in LHC, a dedicated cross-calibration of all the above-mentioned systems was carried out with beam in 2016. Additionally, dedicated optics measurements were also performed in order to determine with the highest possible accuracy the amplitude function at the interaction points and at the position of the profile monitors. Results of these measurements are presented in this paper.

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MOPAB131

Transverse Emittance Measurements Using LHCb's Beam-Gas Interactions

detector, real-time, experiment, operation

441

T.B. Hadavizadeh
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
R. Alemany-Fernández, F. Alessio, C. Barschel, G.R. Coombs, M. Ferro-Luzzi, R. Matev
CERN, Geneva, Switzerland

Measurements of the transverse beam emittance are of great importance at particle accelerators such as the LHC in order to monitor, understand and improve the performance of the machine. A number of profile monitors at the LHC are capable of measuring the transverse emittance from a range of different processes including wire scanners and beam synchrotron light monitors, each having advantages and shortcomings. It is possible additionally to measure the beam profiles using interaction vertices reconstructed in LHCb's vertex locator (Velo). Interactions between colliding beam particles and between beam particles and residual gas nuclei are used to build up a picture of the beam profiles. To guarantee the reliability and quality of the different emittance measurements, a dedicated cross-calibration was performed during a machine development period in October 2016. The results obtained with the LHCb Velo during this cross-calibration are presented here.

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MOPAB132

Beam Size Measurement Using High Aspect Ratio LIGA Apertures in an X-Ray Pinhole Camera

electron, radiation, synchrotron, status

445

L.M. Bobb, G. Rehm
DLS, Oxfordshire, United Kingdom

For optimal brilliance third generation light sources operate at a low emittance and low coupling. Commonly, transverse beam profile measurements are provided by direct imaging of the electron beam using X-ray pinhole cameras. From these beam size measurements and given knowledge of the lattice parameters the emittance, coupling and energy spread are calculated. Ideally, the pinhole aperture should be formed in an infinitely thin screen. However, due to the penetration of X-rays in the keV spectral range, stacked tungsten blades are often used to form the pinhole aperture. In this arrangement the absolute size of the pinhole aperture is unknown and cannot be directly measured, which affects the spatial resolution of the imaging system. Here we investigate the use of X-ray Lithography, Electroplating and Moulding (commonly known as LIGA) to fabricate high aspect ratio pinhole apertures in a gold screen of approximately 1 mm thickness.

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MOPAB137

Validation of a Novel Emittance Diagnostic Method for Beams with Significant Space Charge

space-charge, focusing, quadrupole, simulation

451

R.B. Fiorito, C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M.E. Conde, N.R. Neveu, J.F. Power
ANL, Argonne, Illinois, USA
O. Mete Apsimon
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
A.G. Shkvarunets
UMD, College Park, Maryland, USA

Funding: Work supported by the EU under grant agreement 624890, the STFC Cockcroft Institute Core Grant No. ST/G008248/1.
Exact knowledge of beam emittance is of central importance for essentially every accelerator. However, there are only few methods to determine it when the beam has significant space charge. We report on our progress to validate a novel diagnostic method that has been proposed to determine the RMS emittance of an electron beam with space charge. This method uses RMS divergence and beam size data measured at a screen placed in a free drift region for selected values of magnetic focusing strength. A novel algorithm is then used to determine the cross correlation term and consequently the RMS emittance of the beam. Simulations, quadrupole scans, phase space tomography and optical diffraction-dielectric foil radiation interferometry are currently being employed to determine and compare the horizontal (x) and vertical (y) emittances of the 14 MeV witness electron beam at Argonne National Laboratory's Wakefield Accelerator. The results of simulations and current measurements are presented and the advantages of the new technique are discussed.

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MOPAB141

Instrumentation and Its Interaction With the Secondary Beam for the Fermilab Muon Campus

ion, experiment, simulation, vacuum

466

D. Stratakis, B.E. Drendel, M.J. Syphers
Fermilab, Batavia, Illinois, USA
M.J. Syphers
Northern Illinois University, DeKalb, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
The Fermilab Muon Campus will host the Muon g-2 experiment - a world class experiment dedicated to the search for signals of new physics. Strict demands are placed on the beam diagnostics in order to ensure delivery of high quality beams to the storage ring with minimal losses. In this study, we briefly describe the available secondary beam diagnostics for the Fermilab Muon Campus. Then, with the aid of numerical simulations we detail their interaction with the secondary beam. Finally, we compare our results against theoretical findings.

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MOPAB146

Electron Beam Diagnosis Using K-edge Absorption of Laser-Compton Photons

electron, laser, photon, scattering

473

Y. Hwang, T. Tajima
UCI, Irvine, California, USA
C.P.J. Barty, D.J. Gibson, R.A. Marsh
LLNL, Livermore, California, USA

Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
The mean energy, energy spread and divergence of the electron beam can be deduced from laser-Compton scattered X-rays filtered by a material whose K-edge is near the energy of the X-rays. This technique, combined with a spot size measurement of the beam, can be used to measure the emittance of electron bunches, and can be especially useful in LWFA experiments where conventional methods are unavailable. The effects of the electron beam parameters on X-ray absorption images are discussed, along with experimental demonstrations of the technique using the Compact Laser-Compton X-ray Source at LLNL.

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MOPAB150

Imaging the Spatial Modulation of a Relativistic Electron Beam

electron, experiment, scattering, quadrupole

480

C. Zhang, W.S. Graves, L.E. Malin, J. Spence
Arizona State University, Tempe, USA
D.B. Cesar, J.M. Maxson, P. Musumeci, A. Urbanowicz
UCLA, Los Angeles, USA
C. Limborg, E.A. Nanni
SLAC, Menlo Park, California, USA

Funding: Work supported by NSF awards 1632780, 1415583, 1231306 and DOE award de-sc0009914
We describe Bragg diffraction of relativistic electron beams through a patterned Si crystal consisting of alternating thick and thin strips to produce nanometer scale electron density modulations. Multi-slice simulations show that a two-beam situation can be set up where, for a particular thickness of Si, nearly 100% of the electron beam is diffracted. Plans are underway to carry out experiments showing this effect in UCLA's ultrafast electron microscopy lab with 3.5 MeV electrons. We will select either the diffracted beam or the primary beam with a small aperture in the diffraction plane of a magnetic lens, and so record either the dark or bright field magnified image of the strips. Our first goal is to observe the nanopatterned beam at the image plane. We will then investigate various crystal thickness and sample orientations to maximize the contrast in the pattern and explore tuning the period of the modulation through varying magnification.

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MOPAB154

Measurement of Proton Transverse Emittance in the Brookhaven AGS

dipole, injection, flattop, proton

494

H. Huang, L. Ahrens, C.W. Dawson, C.E. Harper, C. Liu, F. Méot, M.G. Minty, V. Schoefer, S. Tepikian, K. Zeno
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
High luminosity and high polarization in RHIC require good control and measurement of emittance in its injector, the Brookhaven AGS. In the past, the AGS emittance has been measured by using an ion collecting IPM during the whole cycle. The beam profiles from this IPM are distorted by space charge forces at higher energy, which makes the emittance determination very hard. The effect has been measured with IPM measurement at different energies with RF off to mitigate the space charge effect. In addition, helical snake magnets and near integer vertical tune for polarized proton operation distort the lattice in the AGS and introduce large beta beating. For more precise measurements of the emittance, we need turn-by-turn (TBT) measurements near injection and beta function measurements at the IPM. The AGS has also been modeled to get the beta functions at the locations of IPM. A new type of electron collecting IPM has been installed and tested in the AGS with proton beam. The vertical beta functions at the IPM locations have been measured with a local corrector near the IPM. This paper summarizes our current understanding of AGS emittances and plans for the further improvements.

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MOPIK017

Simultaneous Generation of Drive and Witness Beam for Collinear Wakefield Acceleration

wakefield, acceleration, controls, quadrupole

535

G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
M.E. Conde, D.S. Doran, W. Gai, J.G. Power
ANL, Argonne, Illinois, USA

Funding: This work is supported by Department of Energy, Office of High Energy Physics, under Contract No. DE-AC02-06CH11357.
Generating the drive and witness bunch for collinear wakefield acceleration (CWFA) requires precise control of the longitudinal bunch shape for each bunch as well as the controlling their separation. The emittance exchange (EEX) beamline and a transverse mask can be used to achieve all of these requirements. First, this EEX-based method can independently control the longitudinal bunch shape of each bunches so that the drive bunch is shaped to generate a high transformer ratio while witness bunch is shaped to suppress its energy spread. Second, the timing jitter between the drive and witness bunch poses a serious limitation to the CWFA scheme but the EEX-based method eliminates this since both bunches are generated at the same time and share the exactly same beamline so there are no relative errors. In this paper, we confirm the feasibility of this EEX-based method for simultaneous generation with simulation for CWFA in a dielectric structure.

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MOPIK022

Experimental Investigation of Field-Emission From Silicon Nano-Cone Cathodes

cathode, electron, vacuum, ion

548

A. Lueangaramwong, C. Buzzard, V. Korampally, O. Mohsen, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
S. Chattopadhyay
Northern Illinois Univerity, DeKalb, Illinois, USA
R. Divan
Argonne National Laboratory, Argonne, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Funding: This work is supported by the NSF grant PHY-1535401 with Northern Illinois University
Field emission cathode are capable of forming electron beam with extreme brightness via strong-field excitation from applied electrostatic, or electromagnetic (radiofrequency and laser) fields. Our group, in collaboration with the Argonne Center for Nanoscale Material, has recently developed nanocone cathode. The present paper reports on the experimental characterization of these cathodes both configured as a single-cone emitter or as large arrays of tightly-packed emitter. The tests carried in a diode setup are capable of measuring IV characteristic curves and beam distributions.

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MOPIK030

Design of a Beamline From a TR24 Cyclotron for Biological Tissues Irradiation

cyclotron, proton, quadrupole, dipole

564

E. Bouquerel, T. Adam, G. Heitz, C. Maazouzi, C. Matthieu, M. Pellicioli, M. Rousseau, C. Ruescas, J. Schuler, E.K. Traykov
IPHC, Strasbourg Cedex 2, France

Funding: The PRECy project is supported by the Contrat de Projet Etat-Région (CPER) Alsace Champagne-Ardenne Lorraine.
The PRECy project foresees the use of a 16-25 MeV energy proton beam produced by the recently installed TR24 cyclotron, CYRCé, at the Institut Pluridisciplinaire Hubert Curien (IPHC) of Strasbourg for biological tissues irradiation. One of the exit ports of the cyclotron will be used for this application along with a combination magnet. The platform will consist of up to 3 or 5 experimental stations linked to beamlines in a dedicated area next to the cyclotron vault. One of the beamlines will receive proton beams of a few cm diameter at intensities up to 100 nA. The status of the design of this first beam line is presented.

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MOPIK042

Beam-Based Kicker Waveform Measurements Using Long Bunches

kicker, flattop, injection, proton

599

V. Forte, W. Bartmann, J.C.C.M. Borburgh, M.A. Fraser, L. Sermeus
CERN, Geneva, Switzerland

The increased bunch length demanded by the LHC Injectors Upgrade (LIU) project to mitigate emittance growth from space-charge on the PS injection plateau puts strong constraints on the rise-times of the recombination kickers in the transfer lines between the CERN Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS). A beam-based technique has been developed to validate the waveforms of the recombination kickers. In this paper high-resolution measurements are presented by extracting the intra-bunch deflection along bunches with lengths comparable to or longer than the rise-time of the kicker being probed. The methodology has been successfully applied to the three vertical recombination kickers named BT1. KFA10, BT4. KFA10 and BT2. KFA20, and benchmarked with direct measurements of the kicker field made using a magnetic field probe. This paper describes the beam-based technique, summarises the main characteristics of the measured waveforms, such as rise-time and flat-top ripple, and estimates their impact on beam brightness.

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MOPIK054

Towards the Low Emittance CANDLE Storage Ring

lattice, wiggler, storage-ring, synchrotron

641

A. Sargsyan, G.A. Amatuni, V. Sahakyan, V.M. Tsakanov, G.S. Zanyan
CANDLE SRI, Yerevan, Armenia

Stimulated by the recent approaches and developments in low emittance lattice design and magnet technology a continuous process of CANDLE storage ring lattice improvement has been launched aiming to keep the project competitive in the field. The main goal of the upgrade program is to bring the beam emittances down to sub-nm level, having the condition of cost and performance efficiency. This paper summarizes the results obtained in the above-mentioned direction. The main design characteristics and linear/nonlinear beam dynamics aspects of the obtained new lattices are presented.

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MOPIK056

On the Ariel Pre-Separator

dipole, target, ion, optics

648

S. Saminathan, R.A. Baartman
TRIUMF, Vancouver, Canada

Funding: Funded under a contribution agreement with NRC (National Research Council Canada) and Capital funding from CFI (Canada Foundation for Innovation).
Two new independent target ion sources with dedicated pre-separators will be built in the ARIEL facility to triple the radioactive ion beam production at TRIUMF. A compact Nier-Johnson type of pre-separator has been designed to achieve a mass resolving power of 300 in order to minimize the undesired radioactive species contaminating the downstream beamlines. It consists of a 112 degree magnetic and a 90 degree toroidal electrostatic dipole with deflection in opposite direction. It also contains electrostatic quadrupole elements in between the dipoles. The electrostatic dipole compensates the energy dispersion of the magnetic dipole. This allows an achromatic mode of operation resulting in a high mass resolving power downstream to the electrostatic deflector even for beams with a high energy spread. We present the result of beam optics calculations for the ARIEL pre-separator.

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MOPIK059

Linear and Nonlinear Optimizations of Combined 7BA-6BA Lattices for the Future Upgrade of SOLEIL

lattice, injection, dipole, sextupole

659

A. Loulergue, P. Brunelle, H.C. Chao, A. Nadji, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

Previous MBA studies converged to a combination of 7BA and 6BA structures, in terms of the target horizontal emittance of below 300 pm-rad, where the effect of anti-bends, dipole field values, and straight section lengths were investigated. Inspired by the successful lattice designs elsewhere adopting the interleaved sextupole scheme with dispersion bumps originally developed at the ESRF, the 7BA-6BA structures adopting this scheme are studied in details in parallel to those without it. The former aims at the horizontal emittance in the 200-300 pm-rad range with on and off-momentum dynamic acceptances sufficiently large for off-axis injection and good Touschek lifetime. The latter pursues the lower bound of the reachable horizontal emittance with quadrupole and sextupole strengths in the feasible range with maximum dynamic acceptance. The option of non-standard on-axis injection such as displacing the injected beam longitudinally is envisaged for the latter solutions. In both lattices, the numerical search using MOGA-based codes is employed extensively. The studies focus on the impact of linear optics and straight section lengths on the off-momentum and nonlinear properties.

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MOPIK060

Applying MOGA to Search Linear Lattice in Soleil Upgrade Project

lattice, sextupole, synchrotron, quadrupole

662

H.C. Chao, P. Brunelle, R. Nagaoka
SOLEIL, Gif-sur-Yvette, France

In the community of synchrotron radiation facilities, multi-bend structure becomes the trend of the storage ring design toward lower emittance. For SOLEIL upgrade project, the 7BA-6BA hybrid structure is one of the current options. This paper puts the focus on the 7BA section. There are many degrees of freedom to tweak and many constraints to follow. Here, the idea is to search and build the linear lattice utilizing Multi-Objective Genetic Algorithm (MOGA), which is efficient dealing with higher dimension optimization problems. Within MOGA, subsidiary matchings are performed to ensure certain criteria when the new generation is bred. Delicate designs and manipulations of the objective functions are needed, in order to have a better convergence without being trapped in a local minimum. The results will be shown and discussed.

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MOPIK068

Beam Dynamics Design Parameters for KONUS Lattices

lattice, linac, acceleration, cavity

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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MOPIK070

Notes on Relations between Slice and Projected Beam Parameters

FEL, betatron

689

V. Balandin, N. Golubeva
DESY, Hamburg, Germany

We consider some aspects of the relations between slice and projected beam parameters.

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MOPIK071

Dispersion and Beam Optic Parameter Measurements in the Transport Line (E-Weg) from DESY II to PETRA III

optics, quadrupole, injection, synchrotron

692

G.K. Sahoo, K. Balewski, H. Ehrlichmann, J. Keil, R. Wanzenberg
DESY, Hamburg, Germany

The transport line E-Weg extends from the extraction septum in DESY II to the injection septum in PETRA III, and transports electrons at a beam energy of 6.0 GeV. It consists of 3 parts. The first part is in DESY tunnel, the second part is a long drift space in a slanted tube and the third part is in PETRA III tunnel. The vertical plane difference between the tunnels is 1.28 m. The optics was derived from initial values at Transfer Point (UGP) from a previous optics. The total length of the transfer line is about 203 m. Ten screen monitors are used to estimate the profiles of the beam spot for the optics measurements, while 8 BPMs, mostly adjacent to the screens, are used to compare and control the orbits. Two scrapers are installed on either side of the long drift space to trim the beam dimensions in transverse plane. Two FCTs are used to measure the beam current and transfer efficiency. The transverse dispersion and beta functions are measured by extracting the beam from DESY at different energies and analysing the beam profiles at the screen as well as positions at BPMs. The details of such measurements are reported in this paper.

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MOPIK088

Vertical Emittance Reduction in the SSRF Phase II Project

coupling, quadrupole, alignment, sextupole

733

C.L. Li, B.C. Jiang, Z.B. Li, M.Z. Zhang, Q.L. Zhang, W.Z. Zhang
SINAP, Shanghai, People's Republic of China

The Shanghai Synchrotron Radiation Facility (SSRF) Phase II beamline project (SSRF Phase II) will implement the new lattice with dual-canted insertion devices, superbends and superconducting wiggler. The emittance coupling is one of the most important parameters for the high brightness storage ring light sources. It is often less than 1% in the third-generation storage ring light sources. In this paper, the sensitivity of emittance coupling to magnetic alignment errors in the SSRF Phase II is presented. Sixty skew quadrupole magnets are utilized to correct the emittance coupling with gradient descent algorithm. The emittance coupling obtained in the SSRF Phase II lattice is below 0.3%.

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MOPIK096

Predictability of the Beam Quality During RFQ Voltage Tuning

rfq, simulation, distributed, quadrupole

748

A. Ponton
ESS, Lund, Sweden
A.C. France
CEA/IRFU, Gif-sur-Yvette, France

It has previously been demonstrated that certain spatial harmonics of the dipolar and quadrupolar components of the RFQ voltage have stronger effects on the beam quality than others*. The study suggested that, during the tuning process to compensate for manufacturing errors, some harmonic contents (other than the first ones) should be minimized. The analysis presented in this paper looks at how we can predict the beam quality knowing the content of each voltage harmonics. We propose also a strategy to minimize the impacts of the voltage errors on the output beam phase space during the tuning phase.
* A. Ponton, A.C. France, Y.I. Levinsen, O. Piquet, B. Pottin, and E. Sargsyan, Voltage Error Studies in the ESS RFQ, in Proc. 7th International Particle Accelerator Conference (IPAC'16), Busan, Korea, May 2016, paper THPMB039, pp. 3320-3323, ISBN: 978-3-95450-147-2

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MOPIK097

Vertical Dispersion and Betatron Coupling Correction for FCC-ee

quadrupole, sextupole, coupling, collider

752

S. Aumon, B.J. Holzer
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

The FCC-ee project foresees to build a 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁵ cm^-2s^-1. To reach such performances, an extreme focusing of the beam is required in the interaction regions with a low vertical beta function of 2~mm at the IPs. Moreover, the FCC-ee physics program requires very low emittances never achieved in a collider with 1~nm for ε_x and 2~pm for ε_y, bringing down the coupling ratio to 2/1000. Thus, coupling and vertical dispersion sources have to be controlled carefully. This paper describes the tolerance of the machine to magnet alignment errors as well as the optics correction methods that were implemented, such as the Orbit Dispersion Free Steering, in order to bring the vertical dispersion to reasonable values. The correction of the betatron coupling, being also a very important source of emittance growth, has been integrated to a challenging correction scheme to keep the vertical emittance as low as possible.

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MOPIK103

Operation with Carbon Stripping Foils at ISIS

injection, electron, operation, synchrotron

771

H.V. Cavanagh, B. Jones
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS facility at the Rutherford Appleton Laboratory is a pulsed neutron and muon source for physical and life science research. Up to 3·10¹³ protons per pulse are accelerated to 800 MeV in the 50 Hz rapid cycling synchrotron that serves two spallation neutron targets. Charge exchange injection of 70 MeV H' ions into the synchrotron takes place over 130 turns. For over 30 years ISIS has used 40×120 mm aluminium oxide stripping foils, produced in-house [1]. Recently, foil preparation and installation processes have been simplified with the use of commercially available 40×60 mm carbon stripping foils. This paper summarises operational experiences with diamond-like-carbon (DLC) and graphene foils. Radiological analysis, atomic force microscope (AFM) imaging of foils and off-line irradiation with a 1.5 keV electron gun are also discussed.

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MOPIK111

Initial Performance Measurements of Multi-GHz Electron Bunch Trains

electron, laser, gun, cathode

795

D.J. Gibson, R.A. Marsh
LLNL, Livermore, California, USA
Y. Hwang
UCI, Irvine, California, USA

Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
LLNL's compact laser-Compton based x-ray source is currently producing up to 35 keV photons, with the capability to upgrade to 250 keV. Increasing the average brightness of such sources requires increasing the electron beam current. To avoid degradation of the narrow-bandwidth performance of the source, the per-bunch charge shouldn't increase; the effective repetition rate of the electron beams must be raised. It has been proposed* to generate bunch trains of several hundred pulses spaced by the period of X-band RF (~87 ps), which raises questions about beam-loading effects on the energy uniformity of the bunches and wakefield effects degrading the emittance of later bunches, compromising the x-ray quality. As a first test of this concept, we have installed into the electron-generating laser of our system optical pulse-stacking hardware to allow generation of 16-electron-bunch trains. Here we present the current status of our x-ray source, along with initial results using this new multi-bunch train. This includes characterization of collective electron beam energy spread and emittance growth.
* D.J. Gibson, et al., IPAC2012.

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MOPIK112

High Average Power Deuteron Beam Dynamics

neutron, target, quadrupole, diagnostics

798

R.A. Marsh, G.G. Anderson, S.G. Anderson, D.L. Bleuel, M.L. Crank, P. Fitsos, D.J. Gibson, M. Hall, M.S. Johnson, B. Rusnak, J.D. Sain, R. Souza, A. Wiedrick
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
Lawrence Livermore National Lab (LLNL) is developing an intense, high-brightness fast neutron source to create sub-mm-scale resolution neutron radiographs and images. A pulsed 7MeV, 300μA average-current commercial deuteron accelerator will produce an intense source (10¹¹ n/s/sr at 0 deg) of fast neutrons (10MeV) using a novel neutron target with a small (1.5mm diameter) beam spot size to achieve high resolution. A highly flexible multi-accelerator beamline has been developed allowing for the use of both 4MeV and 7MeV RFQ/DTL deuteron accelerators. TRACE3D has been used to model the beam transport and design the quadrupole lattice and results will be presented including iterated design within beamline mechanical constraints, sensitivities, and multiple use of the magnets. Because of the high power density of such a tightly focused, modest-energy ion beam, intercepting beam diagnostics are extremely challenging, motivating novel concepts and extensions of current techniques to higher average power densities. Full duty factor beamline diagnostics will be discussed including charge, position, emittance via beam-induced fluorescence, and a full power beam dump and Faraday cup.

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MOPIK113

Beam Phase Space Tomography for FXR LIA

space-charge, simulation, solenoid, electron

801

Y.H. Wu, Y.-J. Chen
LLNL, Livermore, California, USA

Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Knowing the initial beam parameters entering an accelerator or a downstream beamline allows us to select transport tunes optimized for a desired accelerator performance. In this study, we report unfolding LLNL's FXR [1] beam parameters by using the tomography technique [2, 3] to construct the beam phase space along the accelerator's downstream beamline. The unfolded phase spaces from tomography and simulations are consistent.

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MOPIK114

End-to-End Energy Variation Study for Induction Radiography Accelerator

target, beam-transport, solenoid, simulation

804

Y.H. Wu, Y.-J. Chen
LLNL, Livermore, California, USA

Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Energy variation study for beam transport from the entrance of a conceptual induction radiography accelerator to the x-ray target has been reported previously [1]. In this report, we have extended the study upstream to the injector. To achieve minimum emittance growth and to obtain a desired final beam size, we have developed three optimal tunes. Among them, one optimal tune, capable of supressing beam break-up instability and producing acceptable corkscrew motions, is used to study the energy variation effects on radiography performance. The study shows that ±3% energy variation is acceptable.

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MOPIK115

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

linac, 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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MOPIK118

Model Based Optics Studies in the MEBT Section of SNS

linac, 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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MOPVA001

Coherent X-Ray Radiation From Electron Beam Processed by Channeling and Emittance Exchange

electron, photon, radiation, laser

845

I. Lobach, A.I. Benediktovitch
BSU, Minsk, Belarus

Presented contribution theoretically studies a novel scheme of compact intense x-ray radiation source. In the scheme, longitudinally modulated electron beam emits x-rays by Inverse Compton Scattering (ICS). The setup's feature is the way how longitudinal density modulation in angstrom scale is created. There are three stages of processing of initial beam of relativistic electrons: 1. First, the electrons cross a crystal plate in channeling regime. It is shown that upon leaving the crystal, the electron beam acquires discernible transverse modulation in angstrom scale. It is taken into account that not all electrons are captured in channeling mode and that some of those that do may leave it as they travel through the crystal slab. 2. Further, the beam is transported to Emittance Exchange (EEX) line, in which the direction of modulation is tilted and the beam becomes longitudinally modulated. The scale of modulation remains the same. 3. Finally, intense quasi-coherent x-ray radiation is emitted by ICS. Numerical estimations show that coherent contribution to intensity is considerable for feasible parameters of used beam, components of EEX line and laser producing photons for ICS.

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MOPVA010

Setup and Status of an SRF Photoinjector for Energy-Recovery Linac Applications

gun, SRF, laser, cathode

865

T. Kamps, D. Böhlick, A.B. Büchel, M. Bürger, P. Echevarria, A. Frahm, F. Göbel, S. Heling, A. Jankowiak, S. Keckert, H. Kirschner, G. Klemz, J. Knobloch, G. Kourkafas, J. Kühn, O. Kugeler, A.N. Matveenko, A. Neumann, N. Ohm-Krafft, E. Panofski, F. Pfloksch, S. Rotterdam, M.A.H. Schmeißer, M. Schuster, H. Stein, J. Ullrich, A. Ushakov, J. Völker
HZB, Berlin, Germany
I. Will
MBI, Berlin, Germany

Funding: The work is funded by the Helmholtz-Association, BMBF, the state of Berlin and HZB.
The Superconducting RF (SRF) photoinjector programme for the energy-recovery linac (ERL) test facility BERLinPro sets out to push the brightness and average current limits for ERL electron sources by tackling the main challenges related to beam dynamics of SRF photoinjectors, the incorporation of high quantum efficiency (QE) photocathodes, and suppression of unwanted beam generation. The paper details the experimental layout of the SRF photoinjector and the gun test facility GunLab at Helmholtz-Zentrum Berlin.

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MOPVA018

Resonant Coherent Diffraction Radiation System at ERL Test Accelerator in KEK

cavity, radiation, resonance, experiment

887

Y. Honda, A. Aryshev, R. Kato, T. Miyajima, T. Obina, M. Shimada, R. Takai, N. Yamamoto
KEK, Ibaraki, Japan

Funding: This work was supported by JSPS KAKENHI Grant Number 16H05991
An Energy Recovery Linac can produce a low emittance and short bunch beam at a high repetition rate. A test accelerator, compact-ERL, has been operating in KEK for development works of technologies related to ERL and CW-Superconducting accelerators. In a special beam operation mode of bunch compression, a short bunch beam of ~150 fs at the repetition rate of CW 1.3 GHz can be realized in the return-loop. One of the promising applications of such a short bunch beam is a high power THz radiation source produced by a coherent radiation. When a charged particle beam passes close to a conductive target, a radiation called diffraction radiation is produced. If the target mirrors form an optical cavity which fundamental frequency matches the repetition frequency of the beam, the radiation resonates in the cavity, resulting in extracting a huge radiation power determined by the loss of the cavity. We plan to perform an experiment of the resonant coherent diffraction mechanism in the return-loop of the compact-ERL to test the feasibility to be a wide band high power THz source. We report the design of the experimental setup to be installed in the summer of 2017.

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MOPVA019

60 pC Bunch Charge Operation of the Compact ERL at KEK

operation, laser, cavity, linac

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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MOPVA026

Effects of Insertion Devices on Stored Electron Beam of High Energy Photon Source

undulator, photon, insertion, brilliance

911

X.Y. Li, Z. Duan, D. Ji, Y. Jiao, Y.F. Yang
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS) is a 4th generation, 6-Gev, ultralow-emittance, photon source project in China. High brightness hard X-ray beams at the energy particularly above 10kev are provided by insertion devices installed in straight sections of the storage ring. Brightness tuning curves of 14 ID beamlines planned in HEPS first stage are obtained after designing their parameters. However the presence of these insertion devices produce several effects on the beam performances including betatron tunes, betatron amplitude functions, closed orbit, emittance and dynamic aperture etc. It is found that the vertical octupole effect due to the fourteen IDs under the present schemes produce the most significant effect on the vertical dynamic aperture reduction. The ID field error effects on close orbit can be completely compensated by two correctors adjacent the ID at the both side. The horizontal emittance reduces to 36pm.rad due to the damping wiggler effect of IDs with field error after the orbit correction is also obtained.

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MOPVA029

Conceptual Design of a Pre-Booster Ring for the FCC e⁺e⁻ Injector

booster, extraction, damping, injection

917

O. Etisken, A.K. Çiftçi
Ankara University, Faculty of Sciences, Ankara, Turkey
Y. Papaphilippou
CERN, Geneva, Switzerland

The FCC-ee injector complex needs to produce and to transport a high-intensity e⁺/e⁻ beam at a fast repetition rate of about 0.1 Hz for topping up the collider at its collision energy. A basic parameter set exists for all the collider energies, assuming a 10 GeV linac operating with a large number of bunches being accumulated in the existing SPS, which serves as pre-accelerator and damping ring before the bunches are transferred to the high-energy booster. The purpose of this study is to provide the conceptual design of an alternative accelerator ring, replacing the SPS in the present scheme. This ring will have injection energy of around 5 GeV and extraction energy of around 20 GeV. Apart from establishing the basic parameters of the ring, the study work will include the optics design and layout, single particle linear and non-linear dynamics optimization, including magnetic and alignment error tolerances. The study will also contain some basic estimation of collective effects and address the issue of synchrotron radiation handling.

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MOPVA031

Low Energy Compact Storage Ring Design for Compton Gamma-Ray Light Source

electron, laser, storage-ring, scattering

921

Z. Pan, J.M. Byrd, C. Sun
LBNL, Berkeley, USA
H. Hao, Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA
W.-H. Huang, C.-X. Tang
TUB, Beijing, People's Republic of China

Gamma-ray sources with high flux and spectral densities are highly demanded by many nuclear experiments. We design a low energy compact storage ring to produce gamma-ray with energy in the range of 4-20 MeV based on Compton backscattering technique. The storage ring energy is 500-800 MeV with the circumference of about 59 m and natural emittance of about 3 nmrad at 500 MeV. In this paper, we present the storage ring lattice design and propose two collision configurations for Compton gamma-ray generation. Intrabeam scattering has been investigated which can increase emittance from 3 nmrad to 6 nmrad horizontally for 500 MeV ring. We also discuss how Compton scattering affects longitudinal and transverse beam dynamics by tracking macro particles using our parallel simulation code. Based on this study, we can further optimize our storage ring lattice design for the higher gamma-ray flux production.

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TUXA1

Towards Diffraction Limited Storage Ring Based Light Sources

storage-ring, lattice, undulator, electron

1203

L. Liu, H. Westfahl Jr.
LNLS, Campinas, Brazil

Experimental x-ray techniques that benefit from the great increase in brightness and coherent flux provided by the fourth generation of synchrotron light sources, based on recent advances in accelerator design and technology, are widely expanding nowadays. The basic ingredient to higher brightness is a further reduction of the electron beam emittance in storage rings dedicated to light sources. However, to fully explore the potential of these new sources, it is necessary to optimize other variables as well, such as the proper matching of electrons and photons phase-space and the possibility of using new kinds of insertion devices. Equally important is to try new ways to improve the integration between the light source capabilities and the experiment needs. In this work, recent progress of low emittance rings will be reviewed and the efforts to improve transverse coherent flux and source-to-beamline integration at the Brazilian Sirius project will be described.

Slides TUXA1 [11.984 MB]

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TUYA1

Linac4: From Initial Design to Final Commissioning

linac, quadrupole, proton, 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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TUOBA2

Commissioning of the MYRRHA Low Energy Beam Transport Line and Space Charge Compensation Experiments

rfq, solenoid, proton, injection

1226

F. Bouly, M.A. Baylac, D. Bondoux
LPSC, Grenoble Cedex, France
J. Belmans, D. Vandeplassche
Studiecentrum voor Kernenergie - Centre d'Étude de l'énergie Nucléaire (SCK•CEN), Mol, Belgium
N. Chauvin, F. Gérardin
CEA/IRFU, Gif-sur-Yvette, France

Funding: This work is supported by the European Atomic Energy Community's (EURATOM) H2020 Programme under grant agreement n°662186 (MYRTE project).
The MYRRHA project aims at the construction of a new research reactor in Mol (Belgium) to demonstrate the nuclear waste transmutation feasibility with an Accelerator Driven System (ADS). In its subcritical configuration, the MYRRHA facility requires a proton beam with a maximum power of 2.4 MW (600 MeV - 4 mA). Such a continuous wave beam will be delivered by a superconducting linear accelerator (linac) which must fulfil very stringent reliability requirements to ensure the safe ADS operation with a high level of availability. The linac injector will be composed of: a proton source, a low energy beam transport line (LEBT), a 176 MHz RFQ and CH-DTL cavities. The LEBT prototype has been built and is presently installed and operated at LPSC Grenoble (France). An experimental program, to optimise the tuning of the line, the beam transport, and to study the space charge compensation mechanism, is in progress. We here review the main achievements of the LEBT commissioning. Experimental results will be presented and discussed, in particular the influence of the residual gas (type and pressure) on the beam dynamics.

Slides TUOBA2 [3.929 MB]

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TUZB1

Final Results From the Clic Test Facility (CTF3)

linac, operation, acceleration, 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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TUZB2

Commissioning Status of High Luminosity Collider Rings for SuperKEKB

electron, solenoid, quadrupole, positron

1275

H. Koiso
KEK, Ibaraki, Japan

SuperKEKB project aims to obtain the world's highest luminosity of 8x10³⁵/cm/s, in order to discover new particle physics beyond the Standard Model. Key technologies for the high luminosity are nano-beam scheme at the collision point and high positron and electron stored current with low emittance, which require the significant upgrade of both the injector and the collider rings. Recently commissioning of the renewal collider rings has been performed without final focus magnets and the Belle II detector (Phase 1). This talk gives results of the Phase 1 commissioning and construction status toward the first beam collisions (Phase 2).

Slides TUZB2 [64.509 MB]

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TUOCB1

Progress in the Design of Beam Optics for FCC-ee Collider Ring*

quadrupole, collider, optics, sextupole

1281

K. Oide, K. Ohmi
KEK, Ibaraki, Japan
M. Benedikt, H. Burkhardt, B.J. Holzer, A. Milanese, J. Wenninger, F. Zimmermann
CERN, Geneva, Switzerland
A.P. Blondel, M. Koratzinos
DPNC, Genève, Switzerland
A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia
M. Boscolo
INFN/LNF, Frascati (Roma), Italy

The beam optics for the FCC-ee collider has been updated: (a) the layout is adjusted to a new footprint of FCC-hh, (b) the design around the interaction point is refined considering a number of machine-detecor interface issues, (c) the arc lattice is refined taking realistic magnet designs into account, (d) the β^* and betatron tunes are re-optimized according to recent results of the beam-beam simulations, and more. These changes make the collider design more realistic without performance degradation.

Slides TUOCB1 [4.891 MB]

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TUPAB005

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

linac, 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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TUPAB009

Design Study on CEPC Positron Damping Ring and Bunch Compressor

damping, linac, positron, 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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TUPAB014

Preliminary Design of FCC-ee Pre-Injector Complex

linac, 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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TUPAB015

Pulsed Beam Tests at the SANAEM RFQ Beamline

rfq, proton, cavity, plasma

1341

G. Turemen, Y. Akgun, A. Alacakir, I. Kilic, B. Yasatekin
TAEK - SANAEM, Ankara, Turkey
F. Ahiska
EPROM Electronic Project & Microwave Ind. and Trade Ltd. Co., Ankara, Turkey
E. Cicek
Gazi University, Faculty of Arts and Sciences, Teknikokullar, Ankara, Turkey
E. Ergenlik, S. Ogur, E. Sunar, V. Yildiz
Bogazici University, Bebek / Istanbul, Turkey
G. Unel
UCI, Irvine, California, USA

Funding: Turkish Atomic Energy Authority
A proton beamline consisting of an inductively coupled plasma (ICP) source, two solenoid magnets, two steerer magnets and a radio frequency quadrupole (RFQ) is developed at the Turkish Atomic Energy Authority's (TAEA) Saraykoy Nuclear Research and Training Center (SNRTC-SANAEM) in Ankara. In Q4 of the 2016 the RFQ was installed in the beamline. The high power tests of the RF power supply and the RF transmission line were done successfully. The high power RF conditioning of the RFQ was performed recently. The 13.56 MHz ICP source was tested in two different conditions, CW and pulsed. The characterization of the proton beam was done with ACCTs, Faraday cups and a pepper-pot emittance meter. Beam transverse emittance was measured in between the two solenoids of the LEBT. The measured beam is then reconstructed at the entrance of the RFQ by using computer simulations to determine the optimum solenoid currents for acceptance matching of the beam. This paper will introduce the pulsed beam test results at the SANAEM RFQ beamline. In addition, the high power RF conditioning of the RFQ will be discussed.

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TUPAB020

AREAL 50 MeV Electron Accelerator Project for THz and Middle IR FEL

radiation, electron, gun, FEL

1355

G.A. Amatuni, Z.G. Amirkhanyan, V.S. Avagyan, A. Azatyan, V. Danielyan, H. Davtyan, S.G. Dekhtiarov, N. Ghazaryan, B. Grigoryan, L. Hakobyan, M. Ivanyan, V.G. Khachatryan, E.M. Laziev, T. Markosyan, N. Martirosyan, Sh.A. Mehrabyan, T. Melkumyan, T.H. Mkrtchyan, V.H. Petrosyan, V. Sahakyan, A. Sargsyan, A.S. Simonyan, A.V. Tsakanian, V.M. Tsakanov, A. Vardanyan, Ta.S. Vardanyan, T.L. Vardanyan, V. V. Vardanyan, A.S. Yeremyan, G.S. Zanyan
CANDLE SRI, Yerevan, Armenia
P.S. Manukyan
SEUA, Yerevan, Armenia
A.V. Tsakanian
HZB, Berlin, Germany

Advanced Research Electron Accelerator Laboratory (AREAL) is an electron accelerator project based on photo cathode RF gun. First phase of the facility is a 5 MeV energy RF photogun, which is currently under operation. The facility development implies energy upgrade to 50 MeV with further delivery of the electron beam to the undulator sections for Free Electron Laser and coherent undulator radiation generation in MIR and THz frequency ranges respectively. In this report the design study of AREAL 50 MeV facility main systems along with the beam dynamics and characteristics of expected radiation are presented.

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TUPAB028

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

SRF, cathode, electron, linac

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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TUPAB033

Design of a Stripline Kicker for the ELBE Accelerator

kicker, electron, neutron, laser

1393

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

ELBE is a linac based cw electron accelerator serving different secondary beams one at a time. Depending on the user demand the bunch repetition rate may vary from single pulse up to 13 MHz. For the future different end stations should be served simultaneously, hence specific bunch patterns have to be kicked to other beam-lines. To use e.g. one bunch out of the bunch train very short kicking durations have to be realized. The variability of the bunch pattern and the frequency resp. switching time are one of the main arguments for a stripline-kicker combined with HV-switches as basic concept. A nearly homogenous field in the kicker has to be realized for uniform deflection of the electron bunch and emittance grow of the bunch has to be kept as low as possible. Furthermore the fast switching ability of the kicker demands for a fast decay of the HV-pulse resp. its reflections in the structure implying a specific design of the kicker elements. For this reason a design with two tapered active electrodes and two ground fenders was optimized in time and frequency domain with the software package CST. Additionally a first prototype was manufactured for laboratory and first beam-line tests.

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TUPAB035

Field Quality of 1.5 m Long Conduction Cooled Superconducting Undulator Coils with 20 mm Period Length

undulator, multipole, photon, synchrotron

1395

S. Casalbuoni, N. Glamann, A.W. Grau, T. Holubek, D. Saez de Jauregui
KIT, Eggenstein-Leopoldshafen, Germany
C. Boffo, T.A. Gerhard, M. Turenne, W. Walter
Babcock Noell GmbH, Wuerzburg, Germany

The Institute for Beam Physics and Technology (IBPT) at the Karlsruhe Institute of Technology (KIT) and the industrial partner Babcock Noell GmbH (BNG) are col-laborating since 2007 on the development of superconducting undulators both for ANKA and low emittance light sources. The first full length device with 15 mm period length has been successfully tested in the ANKA storage ring for one year*. The next superconducting undulator has 20 mm period length (SCU20) and is also planned to be installed in the accelerator test facility and synchrotron light source ANKA. The SCU20 1.5 m long coils have been characterized in a conduction cooled horizontal test facility developed at KIT IBPT. Here we present the local magnetic field and field integral measurements, as well as their analysis including the expected photon spectrum.
*S. Casalbuoni et al., Characterization and long term operation of a novel superconducting undulator with 15 mm period length in a synchrotron light source, Phys. Rev. ST Accel. Beams, vol. 19, p.110702, Nov. 2016.

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TUPAB047

Design of a Low Emittance High Current Photocathode RF Gun for the IPM Linear Accelerator

cavity, gun, focusing, simulation

1431

M. Dayyani Kelisani, H. Shaker
CERN, Geneva, Switzerland
H. Shaker
IPM, Tehran, Iran

The IPM accelerator project is developing a 50 MeV linear accelerator as an injector for a terahertz source or an IR FEL. The design specifications require a laser driven photocathode located in one end of a high gradient RF cavity operated at 3 GHz frequency and a solenoid channel for the beam transport. In this work, we report on the RF design of an special photocathode RF gun and its associated focusing channel for the emittance compensation process along the whole injector.

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TUPAB055

Development of compact magnetic field measurement system available for in-vacuum undulators

undulator, brightness, vacuum, photon

1449

M. Adachi, R. Kato, T. Shioya, K. Tsuchiya
KEK, Ibaraki, Japan

A low-emittance 3-GeV KEK-LS* ring has been designed at KEK. KEK-LS's undulators can produce extremely high brightness light ranging from VUV to X-ray. Brightness of undulator light strongly depends on the phase error of its periodic magnetic field. Then a precise magnetic field adjustment is required in order to prevent the reduction of the brightness performance. Generally, the adjustment is performed by the conventional field measurement system equipped with hole-probes on a huge stone table. But, for the in-vacuum undulator, the measurement must be performed without the vacuum chamber. The additional phase error caused by reattaching the chamber is not negligible for the low emittance rings. Therefore, some groups have developed measurement systems available for the direct field measurement inside the chamber**,***. We have started to develop a compact measurement system. Our system is compacted and stabilized by utilizing the rigid metal beam of the undulator frame instead of the stone table. In the conference, we will report the detail of the system and the present status of the development.
* KEK-LS HP, http://kekls.kek.jp/
** T. Tanaka, et al., Physical Review ST-AB, vol.12, p.120702 (2009).
*** M. Musardo, et al., Proceedings of IPAC2015, Richmond, VA, USA, p.1693 (2015).

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TUPAB065

The Progress of HEPS Booster Design

booster, lattice, storage-ring, injection

1472

Y.M. Peng, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, S.K. Tian, G. Xu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS), a kilometre-scale, ultralow-emittance storage ring light source, is to be built in Beijing, China. For HEPS, a full energy booster synchrotron operating at a frequency of 2Hz is considered. In this paper, we will report the progress of the lattice design and physics studies on HEPS booster, containing the injection consideration, ramping process, error studies, and so on.

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TUPAB074

Measurements of Thermal Emittance for Cesium Telluride Photocathodes in an L-Band RF Gun

laser, gun, electron, cathode

1491

L.M. Zheng, W. Gai, C.-X. Tang
TUB, Beijing, People's Republic of China
W. Gai, C.-J. Jing, W. Liu, N.R. Neveu, J.G. Power, J.H. Shao, E.E. Wisniewski
ANL, Argonne, Illinois, USA
W. Liu
Euclid TechLabs, LLC, Solon, Ohio, USA

The thermal emittance is a major contributor to the final emittance of an electron beam in a photocathode RF gun. In this paper we present measurement results of thermal emittance for the cesium telluride photocathode at the Argonne Wakefield Accelerator (AWA) facility using the quadrupole scan method. Measurements of the thermal emittance vs. the laser spot size are presented.

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TUPAB076

Design of an X-Band Photocathode for Tsinghua Thomson Scattering X-Ray Source

gun, laser, solenoid, cathode

1497

L.Y. Zhou, H.B. Chen, Y.-C. Du, W. Gai, W.-H. Huang, J. Shi, C.-X. Tang, D. Wang, Z. Zhang, Z. Zhou
TUB, Beijing, People's Republic of China

Compared with S-band and C-band accelerating structures, X-band structures can run at a higher accelerating gradient and are more compact in size. In order to obtain higher electron energy in a limited space, a new X-band photo-injector operating at 11.424GHz has been designed at the Accelerator Laboratory of Tsinghua University. The structural design of the X-band photo-cathode RF gun and the accelerating structures as well as the beam dynamics simulation are presented in this paper, followed by the optimization of the structure based on the dispersed optimization experiment method(DOE). The results show that the design satisfies the working requirements with a small space occupied and a high beam quality.

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TUPAB077

A Combined THz/X-ray Source Based on Brake-applied Velocity Bunching and Magnetic Compression

electron, radiation, bunching, laser

1500

R. Huang, Z.G. He, Q.K. Jia, B. Li, W.W. Li, L. Wang, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by Chinese Universities Scientific Fund under Contracts WK2310000063 and WK2310000047
Ultrashort electron beam can be realized by the process of velocity bunching and magnetic compression. Velocity bunching technique is able to compress the bunch at relatively low energy, which presents peculiar challenges when approaching a very high current and a low transverse emittance in photoinjectors. A brake-applied velocity bunching scheme was proposed, so that the transverse emittance of the beam could be almost compensated even if the compression factor was extremely high. By adding a magnetic compressor, one could obtain a shorter beam and achieve the coherent synchrotron radiation in THz range. Meanwhile, when making the final compressed beam collide with the laser, one could acquire high energy X-ray pulses. This opens the possibility for some interesting combinations of pump-and-probe experiments.

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TUPAB083

Commissioning Experience and Beam Optimization for DCLS Linac

linac, gun, 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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TUPAB086

Design Study of a High-Intensity, Low-Energy Electron Gun

gun, electron, simulation, FEL

1517

Q. Zhang, K. Fan, T. Hu, K.F. Liu, Z.Y. Mei
HUST, Wuhan, People's Republic of China

An independently-tunable-cells thermionic RF gun (ITC-RF gun) is adopted in a compact FEL-THz facility due to its compactness, low-cost and high intensity. An electron gun is required to generate maximum beam current of 3.2 A at low energy of 15keV for the ITC-RF gun, which creates difficulties for the design of electron gun because of the strong space charge effect. A double-anode gridded gun structure is adopted that controls the beam current easily while maintains the energy dispersion less than 0.5%, with high perveance and high compression ratio. CST code has been used extensively for design optimization, which includes electrode shape, influences of grid, installation errors. A measurement scheme is also proposed for key parameters verification. Beam current, emittance and energy dispersion can be measured.

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TUPAB094

Emittance Improvements in the MAX IV Photocathode Injector

linac, 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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TUPAB095

The New MAX IV Gun Test Stand

gun, laser, cathode, operation

1537

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

The gun test stand from MAX-Lab has been upgraded and moved to a new facility at the MAX IV Laboratory. The new test stand will reuse parts of the equipment from the old test stand but a number of improvements to the setup are be made. In this paper we report on the design of the new gun test stand, research plans in the near future as well as planned and possible future research topics.

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TUPAB096

Pulse Shaping at the MAX IV Photoelectron Gun Laser

laser, gun, electron, cathode

1541

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

A motivation for the development of a versatile, programmable source of shaped picosecond pulses for use in photocathode electron gun preinjectors is presented. We present the experimental setup for arbitrary longitudinal pusle shaping of the MAX IV photocathode gun laser. The setup consists of a grating-based Fourier-domain shaper capable of stretching the pulses directly in the UV domain. Preliminary results are presented and discussed.

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TUPAB110

Possible Limits of Plasma Linear Colliders

plasma, electron, scattering, collider

1576

F. Zimmermann
CERN, Geneva, Switzerland

Plasma linear colliders have been proposed as next or next-next generation energy-frontier machines for high-energy physics. I investigate possible fundamental limits on energy and luminosity of such type of colliders, considering acceleration, multiple scattering off plasma ions, intrabeam scattering, bremsstrahlung, and betatron radiation. The question of energy efficiency will also be addressed.

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TUPAB111

Energy Distribution and Work Function Measurements for Metal Photocathodes with Measured Levels of Surface Roughness

electron, FEL, detector, plasma

1580

L.B. Jones, T.S. Beaver, B.L. Militsyn, T.C.Q. Noakes, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S. Mistry
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
S. Mistry
Loughborough University, Leicestershre, United Kingdom

Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 312453.
The minimum achievable emittance in an electron accelerator depends strongly on the intrinsic emittance of the photocathode electron source which is measureable as the mean longitudinal and transverse energy spreads in the photoemitted electrons. Reducing emittance in an accelerator driving a Free Electron Laser (FEL) delivers significant reduction in the saturation length for an x-ray FEL, reducing machine cost and increasing x-ray beam brightness. There are many parameters which affect the intrinsic emittance of a photocathode. Surface roughness is a significant factor*, and consequently the development of techniques to manufacture low roughness photocathodes with optimum emission properties is a priority for the electron source community. In this work, we present transverse energy distribution and work function measurements made using our TESS facility** for electrons emitted from copper and molybdenum photocathodes with differing levels of measured surface roughness.
* Proc. FEL '06, THPPH013, 583-586
** Proc. FEL '13, TUPPS033, 290-293

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TUPAB126

Multi-objective Genetic Optimization of Single Shot Ultrafast Electron Diffraction Beamlines

gun, electron, cathode, cavity

1615

C.M. Gulliford, A.C. Bartnik, I.V. Bazarov
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.M. Maxson
UCLA, Los Angeles, California, USA

We present the results of multi-objective genetic algorithm optimizations of two single-shot ultrafast electron diffraction (UED) beam lines. The first is based on a 225 kV dc gun featuring a novel cryocooled photocathode system and buncher cavity. The second uses a 100 MV/m 1.6 cell normal conducting rf (NCRF) gun, as well as a 9 cell 2 Pi/3 bunching cavity placed between two solenoids. Optimizations of the transverse projected emittance as a function of bunch charge are presented and discussed in terms of the scaling laws derived in the charge saturation limit. Additionally, optimization of the transverse coherence length as a function of final rms bunch length at the sample location have been performed. These results demonstrate the viability of the approaches taken for both beamlines studied as well as the use of using genetic algorithms in the design and operation of UED beamlines.

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TUPAB128

Single Photoemitter Tips in a DC Gun: Limiting Aberration-induced Emittance

electron, cathode, laser, cryogenics

1622

I.V. Bazarov, L. Cultrera, C.M. Gulliford, H. Lee
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
H.K. Fung
Cornell University, Ithaca, New York, USA
J.M. Maxson
UCLA, Los Angeles, California, USA

Ultrafast electron diffraction (UED) offers unique advantages over x-ray diffraction, like stronger scattering cross-section, versatility in sample types and ability to offer smaller apparatus foot print. There is a growing need to increase brightness of electron beams especially for single-shot UED applications. We explore the utilization of field enhancement from a micron-scale single tip inside a DC gun to obtain brighter sub-pC electron beams using a nominal cathode electric field of several MV/m. The additional field enhancement can place moderate voltage sources on par with the highest gradient devices and allow improved performance presently not possible in the existing photoemission guns.

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TUPAB129

Optimization of Beam Dynamics for an S-Band Ultra-High Gradient Photoinjector

brightness, gun, electron, cathode

1626

A.D. Cahill, A. Fukasawa, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
C. Limborg, W. Qin
SLAC, Menlo Park, California, USA

Funding: Work Supported by DOE/SU Contract DE-AC02-76-SF00515, US NSF Award PHY-1549132, the Center for Bright Beams, and DOE SCGSR Fellowship. Travel to IPAC'17 supported by the Div. of Phys. of the US NSF (Accel. Sci. Prog.) and the Div. of Beam Phys. of the APS
New electron sources with improved brightness are desired to enhance the capabilities of FELs, making them more compact and fully coherent. Improvements in electron source brightness can be achieved by increasing electric fields on the cathode of photo-emitted electron guns. Recent developments in pulsed RF accelerator structures show that very high gradient fields can be sustained with low breakdown rates by operating at cryo-temperatures, which when applied to photoguns will lead to a large increase in the electron beam brightness. In particular, our simulations show that when operating with a peak gradient field of 240 MV/m on the cathode of an S-band, electron beam brightness of 80~nC/(mm· mrad)²/mm can be achieved with 100~pC bunches. In this paper, we present the design and optimization of an 1.x cell S-Band RF photoinjector, where the x varies from 4-6. The optimization in brightness has been obtained by using a multi-objective genetic algorithm on the solutions calculated with the ASTRA code. We calculate the optimum length of the rf gun, position of accelerating structure, and laser pulse dimensions for a variety of charges.

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TUPAB137

Evaluation of FEL Performance with a Longer Injector Drive Laser Pulse at the LCLS

laser, FEL, electron, simulation

1651

F. Zhou, Y. Ding, J.P. Duris, S. Gilevich, P. Hering, S. Vetter
SLAC, Menlo Park, California, USA

Funding: US DOE under grant No. DE-AC02-76SF00515.
It is known that the X-ray Free Electron Laser (FEL) performance strongly depends on the beam emittance and peak current. Lengthening injector laser pulse can improve the injector emittance but the injector peak current is notably compromised, in comparison to nominal laser pulse. With this longer laser pulse, a stronger bunch compression through downstream bunch compressors is thus required to keep same final peak current as the nominal laser pulse mode. This process may cause stronger micro-bunching effect. At the LCLS, we perform preliminary experiments with doubling injector laser pulse. In this paper, we present the experimental results of the injector emittance, microbunching effects and FEL performance with the longer drive laser pulse.

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TUPAB138

LCLS-II Injector Physics Design and Beam Tuning

laser, gun, solenoid, cavity

1655

F. Zhou, D. Dowell, P. Emma, J.F. Schmerge
SLAC, Menlo Park, California, USA
C.E. Mitchell, F. Sannibale
LBNL, Berkeley, California, USA

Funding: US DOE under grant No. DE-AC02-76SF00515.
LCLS-II is a proposed high-repetition rate (up to 1 MHz) Free Electron Laser X-ray light source, based on a CW normal conducting (NC) RF gun injector and a CW 4-GeV superconducting (SC) linac, under construction at SLAC. LCLS-II CW injector consists of a 186 MHz NC RF gun, two solenoids, two BPMs, 1.3 GHz NC RF buncher, and 1.3 GHz SC standard 8-cavity cryomodule to boost the beam energy >95 MeV, and 5 pairs of steering correctors. In this paper, we describe the injector physics design including the beam optimization and low level RF requirement, and also present the studies of beam performance with any one SC cavity failure. The beam tuning procedure is developed with the correctors and two BPMs. The simulations of the phase/amplitude calibration for the gun and buncher and beam based alignment for cathode, two solenoids, and RF buncher with the limited diagnostics, will be presented.

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TUPIK013

Improved Electron Beam Quality from External Injection in Laser-Driven Plasma Acceleration at SINBAD

plasma, laser, electron, acceleration

1707

M.K. Weikum, R.W. Aßmann, U. Dorda, A. Ferran Pousa, T. Heinemann, B. Marchetti, E.N. Svystun, P.A. Walker
DESY, Hamburg, Germany
T. Heinemann, F.Y. Li, Z.M. Sheng, M.K. Weikum
USTRAT/SUPA, Glasgow, United Kingdom
T. Heinemann
University of Hamburg, Hamburg, Germany
Z.M. Sheng
Shanghai Jiao Tong University, Shanghai, People's Republic of China

External injection into laser wakefield accelerators is one of the possible routes towards high energy, high quality electron beams through plasma acceleration. Among other reasons this is due to the increased control over the electron beam parameters and overall experimental setup when compared to other plasma schemes, such as controlled self-injection. At the future SINBAD (Short INnovative Bunches and Accelerators at DESY) facility at DESY this technique is planned to be tested experimentally through injection and acceleration of a sub-femtosecond electron beam, produced from a conventional RF-injector, with a charge of around 0.7 pC and initial mean energy of 100 MeV at the plasma entrance. A summary of optimisation steps for the potential experimental setup is presented in this paper, including considerations regarding effects of electron beam self-fields and matching of the beam into the plasma stage. The discussion is complemented by first start-to-end simulations of the plasma accelerator setup based on these findings.

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TUPIK022

Innovative Single-Shot Diagnostics for Electrons From Laser Wakefield Acceleration at FLAME

laser, electron, target, acceleration

1727

F.G. Bisesto, M.P. Anania, E. Chiadroni, A. Curcio, M. Ferrario, R. Pompili
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
A. Zigler
The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel

Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10-100 GV/m), enabling acceleration of electrons to GeV energy in few centimeters. Here we present all the plasma related activities currently underway at SPARC_LAB exploiting the high power laser FLAME. In particular, we will give an overview of the single shot diagnostics employed: Electro Optic Sampling (EOS) for temporal measurement and optical transition radiation (OTR) for an innovative one shot emittance measurements. In detail, the EOS technique has been employed to measure for the first time the longitudinal profile of electric field of fast electrons escaping from a solid target, driving the ions and protons acceleration, and to study the impact of using different target shapes. Moreover, a novel scheme for one shot emittance measurements based on OTR, developed and tested at SPARC_LAB LINAC, used in an experiment on electrons from laser wakefield acceleration still undergoing, will be shown.

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TUPIK026

Simulations of Positron Capture and Acceleration in the Linear Wakefield of Plasma

wakefield, positron, plasma, laser

1737

M.M. Peng, W. Gai
TUB, Beijing, People's Republic of China

We present the study of positrons capturing dynamics in the wakefield of plasma generated either by a laser or electron beam. Only simplified linear wakefield models were used as first order approximation. By analysing the phase space and beam dynamics, we show that phase space for capturing is rather small, only high brightness beam with very short pulse length can be captured with reasonable rate for wakefields of 1 - 10 GeV/m and wave-length of 100 micron.

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TUPIK035

Solenoidal Focussing Internal Target Ring

target, proton, solenoid, dipole

1757

C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

FFAGs have been considered for a high power proton source for a neutron target by means of an internal target. In an internal target type ring, protons are repeatedly passed through a thin foil, producing neutrons and other secondary particles. This technique has the potential to produce higher secondary particle fluxes with modest beam currents and energies. Scattering of the protons causes emittance growth in the beam, but this can be partially offset by energy lost through ionisation of the foil, which causes ionisation cooling. The resultant beams typically have large position and momentum spread, with transverse emittances of order mm. In this paper, the design of a solenoid-focussing ring is studied which may enable containment of large emittance beams.

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TUPIK036

Use of Laser Wakefield Accelerators as Injectors for Compact Storage Rings

laser, electron, storage-ring, injection

1760

K.A. Dewhurst, H.L. Owen
UMAN, Manchester, United Kingdom
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
B.D. Muratori
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work is funded by the STFC (Science and Technology Facilities Council).
Compact storage rings require a compact acceleration solution. We propose the use of a laser wakefield accelerator (LWFA) as an injector for compact electron storage rings to produce synchrotron radiation. In particular, we study the injection of 0.7 GeV and 3 GeV electrons into the DIAMOND storage ring and consider implications for future storage ring design. Whilst laser-based acceleration is well-known as a driver for future electron-positron colliders and future free-electron lasers, here we propose it is also advantageous to provide electrons for 3rd-generation storage rings. The electron beams produced by LWFAs have a naturally very small emittance around 1 nm and moderate energy spread of a few percent. Combining these beam parameters with the compact size of a LWFA makes them highly favourable compared to traditional linac or booster synchrotron injector chains.chains.

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TUPIK099

Beam-Based Alignment for the Rebaselining of CLIC RTML

sextupole, coupling, quadrupole, alignment

1939

Y. Han, L. Ma
SDU, Shandong, People's Republic of China
A. Latina, D. Schulte
CERN, Geneva, Switzerland

The first stage of the CLIC is proposed to be at 380 GeV. So the Ring To Main Linac (RTML), which transport the beams from the damping ring to main linac with minimal emittance growth, should be restudied due to the new beam properties. In this paper the two bunch compressors in the RTML are redesigned. Then a complete study of the static beam-based alignment techniques along RTML is presented. The beam-based correction includes one-to-one and dispersion-free steering, then a global correction using tuning bumps is applied to reduce the final emittance and mitigate the effects of coupling. The results showed that the emittance growth budgets can be met both in the horizontal and vertical planes.

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TUPIK104

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

solenoid, linac, electron, 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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TUPVA005

Impact of the Crossing Angle on Luminosity Asymmetries at the LHC in 2016 Proton Physics Operation

luminosity, experiment, operation, proton

2035

M. Hostettler
LHEP, Bern, Switzerland
F. Antoniou, I. Efthymiopoulos, K. Fuchsberger, G. Iadarola, N. Karastathis, M. Lamont, Y. Papaphilippou, G. Papotti, J. Wenninger
CERN, Geneva, Switzerland

During 2016 proton physics operation at the CERN Large Hadron Collider (LHC), an asymmetry of up to 10% was observed between the luminosities measured by the ATLAS and CMS experiments. As the same bunch pairs collide in both experiments, a difference in luminosities must be of either geometric or instrumental origin. This paper quantifies the impact of the crossing angle on this asymmetry. As the beams cross in different planes in the two experiments, non-round beams are expected to yield an asymmetry due to the crossing angle. Results from crossing angle measurements at both experiments are also shown and the impact on the luminosities is evaluated.

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TUPVA007

Impact of LHC and SPS Injection Kicker Rise Times on Lhc Filling Schemes and Luminosity Reach

injection, kicker, luminosity, timing

2043

W. Bartmann, M.J. Barnes, J. Boyd, E. Carlier, A. Chmielinska, B. Goddard, G. Kotzian, C. Schwick, L.S. Stoel, D. Valuch, F.M. Velotti, V. Vlachodimitropoulos, C. Wiesner
CERN, Geneva, Switzerland

The 2016 LHC proton filling schemes generally used a spacing between injections of batches of bunches into SPS and LHC corresponding to the design report specification for the SPS and LHC injection kicker rise times, respectively. A reduction of the batch spacing can be directly used to increase luminosity without detrimental effects on beam stability, and with no increase in the number of events per crossing seen by the experiments. Measurements and simulations were performed in SPS and LHC to understand if a shorter injection kicker rise time and associated tighter batch spacing would lead to increased injection oscillations of the first and last bunches of a bunch train and eventually also a systematic growth of the transverse emittance. The results were used to define the minimum possible batch spacing for an acceptable emittance growth in LHC, with gains of reductions of about 10% possible in both machines. The results are discussed, including the potential improvement of the LHC luminosity for different filling schemes.

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TUPVA009

Multiparametric Response of the LHC Dynamic Aperture in Presence of Beam-Beam Effects

simulation, luminosity, optics, octupole

2051

D. Pellegrini, F. Antoniou, S.D. Fartoukh, G. Iadarola, Y. Papaphilippou
CERN, Geneva, Switzerland

We performed extended simulations of LHC dynamic aperture (DA) in the presence of beam-beam effects in the weak-strong approximation, evaluating the contributions of parameters such as: tunes, optics, bunch intensity, crossing angle, emittance, chromaticity and current in the Landau octupoles. Here we present a summary of these studies, giving an overview of the amplitude of the LHC operational space and pointing out the remaining margins for mitigation of instabilities. These studies supported the actions deployed during the 2016 run of the LHC, which aimed at maximising its performances. Examples of such actions are the switch to lower emittance beams, the reduction of crossing angle and tune trims. More recently, DA scans have been used to help the definition of the operational scenarios for the 2017 run. Additional room for improvements, for instance by deploying crossing angle levelling, will be explained.

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TUPVA010

Multiparametric Response of the HL-LHC Dynamic Aperture in Presence of Beam-Beam Effects

luminosity, octupole, simulation, beam-beam-effects

2055

D. Pellegrini, S.D. Fartoukh, N. Karastathis, Y. Papaphilippou
CERN, Geneva, Switzerland

We performed extended simulations of HL-LHC dynamic aperture in the presence of beam-beam effects in the weak- strong approximation, evaluating the contributions of param- eters such as: bunch intensity, crossing angle, chromaticity, current in the Landau octupoles and multipole errors. From the beam dynamics point of view, the main differ- ence between the LHC (until 2017) and the HL-LHC is the deployment of the achromatic telescopic squeezing (ATS) optics, allowing not only for a smaller '' reach, but also modifying the phase advances between the lattice correctors (sextupoles, octupoles) and the main IPs, and increasing the peak ' functions in the arcs. These correctors become therefore more efficient for the chromatic correction, but also a mitigation of the beam-beam long range interactions using the Landau octupoles is enabled, resulting in a possible reduction of the normalised crossing angle. The limits have been investigated in a tracking simulation campaign aimed at exploring the operational space for the HL-LHC and two possible options for luminosity levelling.

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TUPVA029

Observations of Emittance Growth in the Presence of External Noise in the LHC

simulation, damping, brightness, experiment

2117

X. Buffat, C. Tambasco, D. Valuch
CERN, Geneva, Switzerland
J. Barranco García, T. Pieloni, C. Tambasco
EPFL, Lausanne, Switzerland

Dedicated experiments were perfomed in the LHC to study the impact of noise on colliding high brightness beams. The results are compared to theoretical models and multiparticle tracking simulations. The impacts on the LHC operation and the HL-LHC project are discussed.

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TUPVA030

Measurement of Beta-Beating Due to Strong Head-on Beam-Beam Interactions in the LHC

dipole, optics, simulation, injection

2121

P. Gonçalves Jorge, J. Barranco García, T. Pieloni
EPFL, Lausanne, Switzerland
X. Buffat, F.S. Carlier, J.M. Coello de Portugal, E. Fol, L.E. Medina Medrano, R. Tomás, A. Wegscheider
CERN, Geneva, Switzerland

The LHC operation relies on a good knowledge of the optics, usually corrected in absence of beam-beam interactions. In a near future, both the LHC and the HL-LHC will need to cope with large head-on beam-beam parameters, the impact on the optics needs to be understood and, if necessary, corrected. The results of a dedicated experiment performed at injection energy are discussed in this paper.

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TUPVA034

SPS Studies in Preparation for the Crab Cavity Experiment

experiment, luminosity, cavity, simulation

2133

A. Alekou, A. Alekou, F. Antoniou, F. Antoniou, G. Arduini, G. Arduini, H. Bartosik, H. Bartosik, R. Calaga, R. Calaga, Y. Papaphilippou, Y. Papaphilippou, Y. Papaphilippou
CERN, Geneva, Switzerland
A. Alekou, R.B. Appleby, R.B. Appleby
UMAN, Manchester, United Kingdom
R.B. Appleby, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

A local Crab Cavity (CC) scheme will recover head-on collisions at the Interaction Points (IPs) of the High Luminosity LHC (HL-LHC), which aims to increase the LHC luminosity by a factor of 3-10. The first time that CC will ever be tested with proton beams will be in 2018 in the SPS machine. The available dedicated Machine Development (MD) time after the installation of the cavities will be limited and therefore good preparation is essential in order to ensure that the MDs are as efficient as possible. This paper presents the simulations and experimental studies performed in preparation for the future MDs and discusses the next steps.

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TUPVA044

Modelling and Measurements of Bunch Profiles at the LHC

synchrotron, radiation, luminosity, scattering

2167

S. Papadopoulou, F. Antoniou, T. Argyropoulos, M. Hostettler, Y. Papaphilippou
CERN, Geneva, Switzerland
M. Fitterer
Fermilab, Batavia, Illinois, USA

The bunch profiles in the LHC are often observed to be non-Gaussian, both at Flat Bottom (FB) and Flat Top (FT) energies. Especially at FT, an evolution of the tail population in time is observed. In this respect, the Monte-Carlo Software for IBS and Radiation effects (SIRE) is used to track different types of beam distributions. The impact of the distribution shape on the evolution of bunch characteristics is studied. The results are compared with observations from the LHC Run 2 data.

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TUPVA046

Beam Energy Scan With Asymmetric Collision at RHIC

cavity, operation, booster, kicker

2175

C. Liu, J.G. Alessi, E.N. Beebe, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, J.J. Butler, R. Connolly, T. D'Ottavio, K.A. Drees, W. Fischer, C.J. Gardner, D.M. Gassner, X. Gu, Y. Hao, M. Harvey, T. Hayes, H. Huang, R.L. Hulsart, P.F. Ingrassia, J.P. Jamilkowski, J.S. Laster, V. Litvinenko, Y. Luo, M. Mapes, G.J. Marr, A. Marusic, G.T. McIntyre, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, C. Naylor, S. Nemesure, I. Pinayev, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, T. Roser, P. Sampson, J. Sandberg, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, S. Tepikian, R. Than, P. Thieberger, J.E. Tuozzolo, G. Wang, Q. Wu, A. Zaltsman, K. Zeno, S.Y. Zhang, W. Zhang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A beam energy scan of deuteron-gold collision, with center-of-mass energy at 19.6, 39, 62.4 and 200.7 GeV/n, was performed at the Relativistic Heavy Ion Collider in 2016 to study the threshold for quark-gluon plasma (QGP) production. The lattice, RF, stochastic cooling and other subsystems were in different configurations for the various energies. The operational challenges changed with every new energy. The operational experience at each energy, the operation performance, highlights and lessons of the beam energy scan are reviewed in this report.

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TUPVA047

IBS Simulation with Different RF Configurations in RHIC

simulation, cavity, proton, injection

2178

C. Liu, A.V. Fedotov, M.G. Minty, V. Ptitsyn
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
This report focuses on three dimensional emittance growth of polarized proton beam due to Intra-Beam Scattering (IBS) at RHIC. Simulations are presented which give guidance on the configuration of the RF systems to mitigate IBS-induced emittance growth. In addition, simulated growth rates are compared with measured emittance evolution at injection, which shows better agreement in longitudinal than transverse dimension. The results in this report will help us better understand the emittance evolution for current RHIC operations and for future operations (eRHIC).

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TUPVA067

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

linac, 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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TUPVA068

The New Injector Design for MYRRHA

cavity, simulation, impedance, rfq

2234

K. Kümpel, P. Müller, D. Mäder, N.F. Petry, H. Podlech
IAP, Frankfurt am Main, Germany

The MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) Project is a planned accelerator driven system (ADS) for the transmutation of long-living radioactive waste. A critical passage for the beam quality and especially for the emittance is the injector. Therefore, a new injector design with improved beam dynamics has been developed, featuring low emittance growth rates while using only room temperature structures. The previous design consisted of a 4-Rod RFQ, 7 room temperature and 5 superconducting CH-DTL cavities and 2 rebuncher cavities, whereas the superconducting cavities in the new design have been replaced by 8 room temperature CHs and an additional rebuncher. The main challenge during the development is achieving the required reliability to reduce the thermal stress inside the planned reactor. Therefore, simulations with CST MICROWAVE STUDIO have been made to compare several cooling concepts and to optimize the cavities, especially in terms of the shunt impedance.

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TUPVA075

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

rfq, linac, 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, simulation, linac, 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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TUPVA094

Beam Dynamics Design of the Muon Linac High-Beta Section

linac, simulation, 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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TUPVA098

Beam Commissioning of Transport Line LRBT of CSNS

linac, cavity, 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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TUPVA101

Study of Different Models on DTL for CSNS

DTL, linac, 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, simulation, neutron, linac

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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TUPVA128

Performance of the CERN Injector Complex and Transmission Studies into the LHC during the Second Proton-Lead Run

ion, injection, proton, extraction

2395

R. Alemany-Fernández, S.C.P. Albright, M.E. Angoletta, J. Axensalva, W. Bartmann, H. Bartosik, P. Baudrenghien, G. Bellodi, A. Blas, T. Bohl, E. Carlier, S. Cettour-Cave, K. Cornelis, H. Damerau, A. Findlay, S.S. Gilardoni, S. Hancock, A. Huschauer, M.A. Jebramcik, S. Jensen, J.M. Jowett, V. Kain, D. Küchler, A.M. Lombardi, D. Manglunki, T. Mertens, M. O'Neil, S. Pasinelli, A. Saá Hernández, M. Schaumann, R. Scrivens, R. Steerenberg, H. Timko, V. Toivanen, G. Tranquille, F.M. Velotti, F.J.C. Wenander, J. Wenninger
CERN, Geneva, Switzerland

The LHC performance during the proton-lead run in 2016 fully relied on a permanent monitoring and systematic improvement of the beam quality in all the injectors. The beam production and characteristics are explained in this paper, together with the improvements realized during the run from the source up to the flat top of the LHC. Transmission studies from one accelerator to the next as well as beam quality evolution studies during the cycle at each accelerator, have been carried out and are summarized in this paper. In 2016, the LHC had to deliver the beams to the experiments at two different energies, 4 Z TeV and 6.5 Z TeV. The properties of the beams at these two energies are also presented

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TUPVA133

Thin Internal Target Studies in a Compact FFAG

target, simulation, scattering, proton

2411

D. Bruton, R.J. Barlow, T.R. Edgecock
University of Huddersfield, Huddersfield, United Kingdom
C. Johnstone
PAC, Batavia, Illinois, USA

The production of radioisotopes using a thin internal target and recycled beam within a compact FFAG design has been studied. Radioisotopes have a wide range of uses in medicine, and recent disruption to the supply chain has seen a renewed effort to find alternative isotopes and production methods. The FFAG design features separate sector magnets with non-scaling, non-linear field gradients which are optimized with magnet geometry to achieve isochronisity at the level of 0.3%, sufficient for Continuous Wave (CW) operation. Simulations have demonstrated that beam currents of up to 10mA can comfortably be achieved with this design. To further improve production efficiency a thin internal target, where the beam passes through the target and is recirculated, may be used. This setup ensures that production takes place within a narrow energy range, potentially increasing production rates and reducing impurities.

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TUPVA136

Using Sloppy Models for Constrained Emittance Minimization at the Cornell Electron Storage Ring (CESR)

lattice, storage-ring, simulation, coupling

2418

W.F. Bergan, A.C. Bartnik, I.V. Bazarov, H. He, D. L. Rubin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.P. Sethna
Cornell University, Ithaca, New York, USA

Funding: DOE DE-SC0013571 NSF DGE-1144153
In order to minimize the emittance at the Cornell Electron Storage Ring (CESR), we measure and correct the orbit, dispersion, and transverse coupling of the beam.* However, this method is limited by finite measurement resolution of the dispersion, and so a new procedure must be used to further reduce the emittance due to dispersion. In order to achieve this, we use a method based upon the theory of sloppy models.** We use a model of the accelerator to create the Hessian matrix which encodes the effects of various corrector magnets on the vertical emittance. A singular value decomposition of this matrix yields the magnet combinations which have the greatest effect on the emittance. We can then adjust these magnet ‘‘knobs'' sequentially in order to decrease the dispersion and the emittance. We present here comparisons of the effectiveness of this procedure in both experiment and simulation using a variety of CESR lattices. We also discuss techniques to minimize changes to parameters we have already corrected.
* J. Shanks, D.L. Rubin, and D. Sagan, Phys. Rev. ST Accel. Beams 17, 044003 (2014).
** K.S. Brown and J.P. Sethna, Phys. Rev. E 68, 021904 (2003).

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TUPVA139

Characterization of the Beam from the RFQ of the PIP-II Injector Test

rfq, quadrupole, ion, ion-source

2425

A.V. Shemyakin, J.-P. Carneiro, B.M. Hanna, L.R. Prost, A. Saini, V.E. Scarpine, V.L. Sista, J. Steimel
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
A 2.1 MeV, 10 mA CW RFQ has been installed and commissioned at the Fermilab's test accelerator known as PIP-II Injector Test. This report describes the measurements of the beam properties after acceleration in the RFQ, including the energy and emittance.

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TUPVA143

Reduction of Beam Losses in LANSCE Isotope Production Facility

proton, beam-losses, DTL, target

2432

Y.K. Batygin
LANL, Los Alamos, New Mexico, USA

The LANSCE Isotope Production Facility (IPF) utilizes a 100-MeV proton beam with average power of 23 kW for isotope production in the fields of medicine, nuclear physics, national security, environmental science and industry. Typical tolerable fractional beam loss in the 100-MeV beamline is approximately 4 x10^-3. During 2015-2016 operation cycle, several improvements were made to minimize the beam losses. Adjustments to the ion source's extraction voltage resulted in the removal of tails in phase space. Beam based steering in low-energy and high-energy beamlines led to the reduction of beam emittance growth. Readjustment of the 100-MeV quadrupole transport resulted in the elimination of excessive beam envelope oscillations and removed significant parts of the beam halo at the target. Careful beam matching in the drift tube linac (DTL) provided high beam capture (75% - 80%) and minimized beam emittance growth in the DTL. After improvements, beam losses in the 100-MeV beamline were reduced by an order of magnitude and reached the fractional level of 5 x10-4.

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TUPVA144

Beam Based Steering in LANSCE Proton Low Energy Beam Transport

quadrupole, proton, beam-transport, alignment

2435

Y.K. Batygin
LANL, Los Alamos, New Mexico, USA

Beam based steering is an important procedure to minimize beam emittance growth. Low energy 750 keV LANSCE proton beam transport line before injection into Drift Tube Linac (DTL) has a length of 10 m and uses 22 quadrupoles, 6 steering magnets, 2 bending magnets, combination of prebuncher and main buncher, beam deflector, and collimators. Matching of the beam with the structure includes providing beam waists at the entrance of RF cavities, and matched beam Twiss parameters at the entrance to DTL. Typical beam emittance growth was at the level of 2-2.5. Beam based steering procedure was implemented to minimize emittance growth in the beamline. It includes determination of beam offset and beam angle entering group of quadrupoles and subsequent correction of beam angle to minimize beam offset in quadrupoles. Implementation of the procedure resulted in significant reduction of emittance growth at the level of 10%.

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TUPVA145

Commissioning of the New SNS RFQ and 2.5MeV Beam Test Facility

rfq, target, ion, ion-source

2438

A.V. Aleksandrov, S.M. Cousineau, M.T. Crofford, B. Han, Y.W. Kang, A.A. Menshov, A. Webster, R.F. Welton, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA
B.L. Cathey, C.C. Peters
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
SNS injector uses a four-vane 402.5MHz RFQ for accelerating the H⁻ beam with 38mA peak current and 7% duty factor to 2.5MeV. The original RFQ, commissioned in 2002, has been able to support SNS operation up to the design average beam power of 1.4MW. However, several problems have developed over almost fifteen years of operation. A new RFQ with design changes addressing the known problems has been built and commissioned up to the design beam power at the new SNS Beam Test Facility (BTF). The BTF consists of a 65 keV H⁻ ion source, a 2.5MeV RFQ, a beam line with advanced transverse and longitudinal beam diagnostics and a 6 kW beam dump. This presentation provides results of the RFQ commissioning and the BTF beam instrumentation commissioning. We also discuss progress of the ongoing multidimensional phase space characterization experiment and future beam dynamics study planned at the SNS BTF.

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TUPVA149

AGS Polarized Proton Operation Experience in RHIC Run17

booster, timing, polarization, proton

2452

H. Huang, P. Adams, J. Beebe-Wang, M. Blaskiewicz, K.A. Brown, C.J. Gardner, C.E. Harper, C. Liu, F. Méot, J. Morris, A. Poblaguev, V.H. Ranjbar, D. Raparia, T. Roser, V. Schoefer, S. Tepikian, N. Tsoupas, K. Yip, A. Zelenski, K. Zeno
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Imperfection and vertical intrinsic depolarizing resonances have been overcome by the two partial Siberian snakes in the Alternating Gradient Synchrotron (AGS). The relatively weak but numerous horizontal resonances are overcome by a pair of horizontal tune jump quads. 70% proton polarization has been achieved for 2·10¹¹ intensity. Further gain can come from maintaining smaller transverse emittance with same beam intensity. The main efforts now are to reduce the transverse emittance in the AGS and Booster, as well as robust jump quads timing generation scheme. This paper summarizes the operation results in the injectors.

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WEOAA3

Realizing a High-Intensity Low-Emittance Beam in the J-PARC 3-GeV RCS

injection, sextupole, resonance, extraction

2470

H. Hotchi, H. Harada, S. Kato, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The J-PARC 3-GeV rapid cycling synchrotron (RCS) has two functions; one as a proton driver to produce pulsed muons and neutrons, and the other as an injector to the following 50-GeV main ring (MR). RCS is now intensively developing a high-intensity beam test to realize a high-intensity low-emittance beam with less beam halo required from MR. This paper presents the recent experimental results, together with detailed discussions for the emittance growth and its mitigation mechanisms.

Slides WEOAA3 [1.732 MB]

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WEOBA2

Hollow Electron Beam Collimation for HL-LHC - Effects on the Beam Core

electron, simulation, experiment, operation

2482

M. Fitterer, G. Stancari, A. Valishev
Fermilab, Batavia, Illinois, USA
R. Bruce, G. Papotti, S. Redaelli, D. Valuch, C. Xu
CERN, Geneva, Switzerland
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the US Department of Energy.
Collimation with hollow electron beams is currently one of the most promising concepts for active halo control in the High Luminosity Large Hadron Collider (HL-LHC). To ensure the successful operation of the hollow beam collimator the unwanted effects on the beam core, which might arise from the operation with a pulsed electron beam, must be minimized. This paper gives a summary of the effect of hollow electron lenses on the beam core in terms of sources, provides estimates for HL-LHC and discusses the possible mitigation methods.

Slides WEOBA2 [2.074 MB]

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WEOBA3

Studies of a Scheme for Low Emittance Muon Beam Production From Positrons on Target

target, positron, scattering, simulation

2486

M. Boscolo, M. Antonelli, M.E. Biagini, O.R. Blanco-García, A. Variola
INFN/LNF, Frascati (Roma), Italy
A. Bacci
Istituto Nazionale di Fisica Nucleare, Milano, Italy
I. Chaikovska, R. Chehab
LAL, Orsay, France
F. Collamati
INFN-Roma1, Rome, Italy
M. Iafrati
ENEA, Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile, Frascati, Italy
L. Keller
SLAC, Menlo Park, California, USA
S.M. Liuzzo, P. Raimondi
ESRF, Grenoble, France
P. Sievers
CERN, Geneva, Switzerland

We are studying a new scheme to produce very low emittance muon beams using a positron beam of about 45 GeV interacting on electrons on target. This is a challenging and innovative scheme that needs a full design study. One of the innovative topics to be investigated is the behaviour of the positron beam stored in a low emittance ring with a thin target, that is directly inserted in the ring chamber to produce muons. Muons will be immediately collected at the exit of the target and transported to two mu+ and mu- accumulator rings. We focus in this paper on the simulation of the e⁺ beam interacting with the target, its degradation in the 6-D phase space and the optimization of the e⁺ ring design mainly to maximize the energy acceptance. We will investigate the performances of this scheme, ring optics plus target system, comparing different multi-turn simulations.

Slides WEOBA3 [3.737 MB]

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WEXB1

Studies and Observations of Beam Dynamics Near a Sum Resonance

resonance, space-charge, synchrotron, simulation

2503

G. Franchetti
GSI, Darmstadt, Germany
S.S. Gilardoni, A. Huschauer, F. Schmidt, R. Wasef
CERN, Geneva, Switzerland

The effect of space charge on bunches stored for long term in a can be severe for beam survival. This may be the case in projects as SIS100 at GSI or LIU at CERN. In the past decade systematic simulation studies and experiments performed at CERN and GSI have highlighted the space charge induced periodic crossing of Â“one dimensionalÂ” resonances as the underlying mechanism of long term beam loss or emittance growth. However only in 2012, for the first time, the effect of space charge on a normal third order coupled resonance was investigated at the CERN-PS. The experimental results have highlighted an unprecedented asymmetric beam response where in the horizontal plane the beam exhibits a thick halo, whereas the vertical profile has only core growth. The quest for explaining these results requires a journey thorough the 4 dimensional dynamics of the coupled resonance investigating the fix-lines, and requires a detailed code-experiment benchmarking also including beam profile benchmarking. This study shows that the experimental results of the 2012 PS measurements can be explained by the dynamics the fixed lines also including the effect of the dispersion.

Slides WEXB1 [18.195 MB]

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WEYB1

Towards a Fully Integrated Accelerator on a Chip: Dielectric Laser Acceleration (DLA) From the Source to Relativistic Electrons

laser, electron, acceleration, simulation

2520

K.P. Wootton, R.J. England, S.G. Tantawi
SLAC, Menlo Park, California, USA
R.W. Aßmann, I. Hartl, W. Kuropka, F. Mayet, A. Rühl
DESY, Hamburg, Germany
D.S. Black, R.L. Byer, H. Deng, S. Fan, J.S. Harris, T.W. Hughes, N. Sapra, O. Solgaard, J. Vuckovic
Stanford University, Stanford, California, USA
B.M. Cowan
Tech-X, Boulder, Colorado, USA
T. Egenolf, U. Niedermayer
TEMF, TU Darmstadt, Darmstadt, Germany
P. Hommelhoff, A. Li, N. Schönenberger
University of Erlangen-Nuremberg, Erlangen, Germany
J. Illmer, J.C. McNeur, A.K. Mittelbach, A.D. Tafel
Friedrich-Alexander Universität Erlangen-Nuernberg, University Erlangen-Nuernberg LFTE, Erlangen, Germany
R. Ischebeck, L. Rivkin
PSI, Villigen PSI, Switzerland
F.X. Kärtner
MIT, Cambridge, Massachusetts, USA
F.X. Kärtner
CFEL, Hamburg, Germany
W. Kuropka, F. Mayet
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
Y.J. Lee, M. Qi
Purdue University, West Lafayette, Indiana, USA
P. Musumeci
UCLA, Los Angeles, California, USA
L. Rivkin
EPFL, Lausanne, Switzerland

Funding: This work was supported by the U.S. Department of Energy, Office of Science, under Contract no. DE-AC02-76SF00515, and by the Gordon and Betty Moore Foundation under grant GBMF4744 (Accelerator on a Chip).
Dielectric laser acceleration of electrons has recently been demonstrated with significantly higher accelerating gradients than other structure-based linear accelerators. Towards the development of an integrated 1 MeV electron accelerator based on dielectric laser accelerator technologies, development in several relevant technologies is needed. In this work, recent developments on electron sources, bunching, accelerating, focussing, deflecting and laser coupling structures are reported. With an eye to the near future, components required for a 1 MeV kinetic energy tabletop accelerator producing sub-femtosecond electron bunches are outlined.

Slides WEYB1 [12.774 MB]

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WEOBB2

Beam Commissioning of the High Intensity Proton Source Developed at INFN-LNS for the European Spallation Source

proton, ion, plasma, ion-source

2530

L. Neri, L. Allegra, A. Amato, G. Calabrese, A.C. Caruso, G. Castro, L. Celona, F. Chines, G. Gallo, S. Gammino, O. Leonardi, A. Longhitano, G. Manno, S. Marletta, D. Mascali, M. Mazzaglia, A. Miraglia, S. Passarello, G. Pastore, A. Seminara, A. Spartà, G. Torrisi, S. Vinciguerra
INFN/LNS, Catania, Italy

At the Istituto Nazionale di Fisica Nucleare Laboratori Nazionali del Sud (INFN-LNS) the beam commissioning of the high intensity Proton Source for the European Spallation Source (PS-ESS) started in November 2016. Beam stability at high current intensity is one of the most important parameter for the first steps of the ongoing commissioning. Promising results were obtained since the first source start with a 6 mm diameter extraction hole. The increase of the extraction hole to 8 mm allowed improving PS-ESS performances and obtaining the values required by the ESS accelerator. In this work, extracted beam current characteristics together with Doppler shift and emittance measurements are presented, as well as the description of the next phases before the installation at ESS in Lund.

Slides WEOBB2 [2.457 MB]

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WEPAB002

Pushing the MAX IV 3 GeV Storage Ring Brightness and Coherence Towards the Limit of its Magnetic Lattice

optics, lattice, storage-ring, brightness

2557

S.C. Leemann
MAX IV Laboratory, Lund University, Lund, Sweden
W.A. Wurtz
CLS, Saskatoon, Saskatchewan, Canada

The MAX IV 3 GeV storage ring is presently being commissioned and crucial parameters such as machine functions, emittance, and stored current have either already been reached or are approaching their design specifications*. Once the baseline performance has been achieved, a campaign will be launched to further improve the brightness and coherence of this storage ring for typical x-ray users. During recent years, several such improvements have been designed**. Common to these approaches is that they attempt to improve the storage ring performance using existing hardware provided for the baseline design. Such improvements therefore present more short-term upgrades. In this paper, however, we investigate medium-term improvements assuming power supplies can be exchanged in an attempt to push the brightness and coherence of the storage ring to the limit of what can be achieved without exchanging the magnetic lattice itself. We outline optics requirements, the optics optimization process, and summarize achievable parameters.
* WEPAB075 & WEPAB076 at IPAC17
** MOPHO05 at PAC2013, TUPRI026 at IPAC'4, PRAB 19 060701 (2016)

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WEPAB033

Experimental Optimization and Characterization of Electron Beams for Generating IR/THz SASE FEL Radiation with PITZ

electron, FEL, simulation, radiation

2650

P. Boonpornprasert, Y. Chen, J.D. Good, H. Huck, I.I. Isaev, D.K. Kalantaryan, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, Y. Renier, T. Rublack, F. Stephan
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
C. Saisa-ard
Chiang Mai University, Chiang Mai, Thailand
Q.T. Zhao
IMP/CAS, Lanzhou, People's Republic of China

The Photo Injector Test facility at DESY, Zeuthen site (PITZ), develops high brightness electron sources for modern linac-based Free Electron Lasers (FELs). The PITZ accelerator can also be considered as a suitable machine for the development of an IR/THz source prototype for pump-probe experiments at the European XFEL. One of the interesting options for the IR/THz generation with PITZ is to generate the radiation by means of a SASE FEL using an uncompressed electron beam with bunch length of a few 10 ps and a peak current of ~200 A. In this paper, results of experimental optimizations and characterizations, including transverse phase space, slice transverse emittance and longitudinal phase space, of electron beams with bunch charges of 4 nC are presented and discussed. The measurements were done with beam momenta of 15 MeV/c and 22 MeV/c. Results of IR/THz SASE FEL calculations by using the GENESIS1.3 code based on the measured beam parameters are also presented and discussed.

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WEPAB036

The Diffraction Limited Light Source Elettra 2.0

dipole, insertion-device, lattice, insertion

2660

E. Karantzoulis
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

Elettra 2.0 is the next generation to replace Elettra, the Italian third generation light source. The new machine will have an emittance of 0.25 nm-rad with coherent flux about two orders of magnitude higher than that of the present machine. In the paper the aspects of its feasibility are described and discussed.

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WEPAB040

Upgrade Plan of Synchrotron Radiation Source at Hiroshima Synchrotron Center, Hiroshima University

storage-ring, synchrotron, radiation, synchrotron-radiation

2670

K. Kawase, S. Matsuba
HSRC, Higashi-Hiroshima, Japan

Hiroshima Synchrotron Radiation Center belonging to Hiroshima University is a user facility of the synchrotron radiation with the wavelength of ultraviolet range for natural science especially including materials and biological sciences. The kely apparatus is an electron storage ring with energy of 700 MeV. This machine is a racetrack shape with large two bending magnets and the injection energy is 150 MeV. It is a very compact size with the circumstance of 30 m, but it has only 2 insertion section and the emittance is much larger than the modern synchrotron radiation sources. Therefore, all of users is eager to upgrade the radiation source with several straight sections and low emittance beam keeping compactness. To meet these requests, we are designing the storage ring based on MAX-III. In this conference, we show the present design of the storage ring and its injector.

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WEPAB043

DQBA Lattice Option for the KEK-LS Project

lattice, insertion-device, insertion, dynamic-aperture

2675

K. Harada, N. Higashi, S. Nagahashi, N. Nakamura, S. Sakanaka, A. Ueda
KEK, Ibaraki, Japan
S.M. Liuzzo
ESRF, Grenoble, France

KEK-LS is a fourth generation 3GeV light source and will be constructed in KEK Tsukuba campus. The lattice is 20 cells of ESRF type HMBA (Hybrid Multi Bend Achromat) with short straight section that enables to double the numbers of insertion device beam lines. The circumference is about 570m, and the horizontal natural emittance about 133pmrad. The conceptual design report (CDR) was published in October 2016. Adding two quadrupole magnets to the short straight section of the original lattice in CDR, the lattice design flexibility, emittance and dynamic apertures are improved. In this presentation, we show this new DQBA (Double Quadrupole Bend Achromat) lattice option for KEK-LS project.

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WEPAB046

New HMBA Lattice for PF-AR

lattice, injection, dynamic-aperture, optics

2684

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

Photon Factory Advanced Ring (PF-AR) has been operated for users about 30 years from 1987. The lattice and optics are not almost changed from the original one as the TRISTAN booster ring constructed in 1984. The lattice employs FODO structure and the horizontal emittance for the 6.5 GeV user run is about 300 nmrad. In order to improve the performance of PF-AR dramatically, the full replacement of the accelerator to the ESRF type HMBA (Hybrid multi bend achromat) lattice is examined. In order to geometrically fit the new lattice to the present PF-AR tunnel, the new ring consists of 12 cells with four long straight sections. The emittance is improved to about 500 pmrad at 3 GeV. With the present user experimental hall at the north half of the ring, at least eight undulator beam lines can be constructed. The simulated dynamic aperture is about 1.5 cm at the long straight section with reasonable magnetic errors and COD correction. The Touschek lifetime is about 6 hours. The beam injection with conventional injection system causes no problem and the beam lifetime is long enough.

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WEPAB047

Concept of a New Generation Synchrotron Radiation Facility KEK Light Source

lattice, undulator, cavity, brightness

2687

T. Honda
KEK, Ibaraki, Japan

KEK has proposed a new SR facility: KEK Light Source (KEK-LS) towards the completion of the first half of the 2020s. The energy and the natural horizontal emittance are 3 GeV and 0.13 nm rad, respectively. To mitigate the intra-beam scattering effect, we are planning to install third harmonic RF cavities. The extremely low emittance ring has been designed based on the Hybrid Multi-Bend Achromatic (HMBA) lattice, which was originally developed at the ESRF upgrade project. We have modified it to insert a short straight section at the center of the unit cell. The number of unit cells is 20, and the circumference is about 570 m. Except for an RF section and an injection section, the ring can accommodate 18 undulators in the long straight sections of 5.6 m, and the additional 20 short straight section of 1.2 m will be used for short-period narrow-gap undulators. If we assume an undulator of the magnetic period 20 mm, total length 5.0 m, and the smallest gap 4 mm, the SR brightness approaches 10²² Photons/mrad²/mm²/s/0.1%B.W. at the X-ray range. It has a high coherent fraction of about 20% at the diffraction limit wavelength 0.32 keV.

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WEPAB052

Progress of the Lattice Design and Physics Studies on the High Energy Photon Source

lattice, injection, booster, storage-ring

2697

Y. Jiao, X. Cui, Z. Duan, Y.Y. Guo, D. Ji, J.Y. Li, X.Y. Li, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, G. Xu, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao
IHEP, Beijing, People's Republic of China

Funding: Work supported by NSFC (11475202, 11405187, 11205171)
The High Energy Photon Source (HEPS) is a 6-GeV, kilometer-scale, ultralow-emittance storage ring light source to be built in Beijing, China. In this paper we will discuss the progress of the lattice design and related physics studies on HEPS, covering issues of storage ring design, booster design, injection design, collective effects, error study, insertion device effects, longitudinal dynamics, etc.

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WEPAB053

Candidate Lattice Design of the HEPS Booster Consisting of Combined-Function Dipoles

dipole, lattice, booster, sextupole

2700

Y. Jiao, Y.M. Peng, G. Xu
IHEP, Beijing, People's Republic of China

Funding: Work supported by NSFC (11475202, 11405187)
The High Energy Photon Source (HEPS) is a 6-GeV, ultralow-emittance, kilometer-scale storage ring light source to be built in China. It is planned to use a 300 MeV linac and a full energy booster as the injector. In this paper we present one of the candidate lattice designs for the HEPS booster, where most of the dipoles are combined with quadrupole and sextupole gradients. Global optimization of the lattice has been done, where the dependencies of the lattice performance on various parameters, including the minimum pole face field, damping partition number, number of dipoles, etc. are discussed.

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WEPAB054

Candidate HEPS Lattice Design With Emittances Approaching the Diffraction Limit of Hard X-Rays

lattice, dipole, storage-ring, brightness

2703

Y. Jiao, S.Y. Chen, G. Xu
IHEP, Beijing, People's Republic of China

Funding: Work supported by NSFC (11475202, 11405187)
The High Energy Photon Source is a 6-GeV, kilometre-scale storage ring light source to be built in Beijing. A lattice of the storage ring was proposed, consisting of 48 hybrid 7BAs, and having a natural emittance of 60 pm and a circumference of ~1.3 km. In this paper, we discuss the possibility of further reducing the emittance to approach the diffraction limit of hard X-ray with 'typical' wavelength of 1 Å. We introduce the considerations on the choice of lattice structure and circumference, and concrete lattice designs.

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WEPAB055

Characterizing the Nonlinear Performance of a DLSR With the Effective Acceptance of the Bare Lattice

lattice, resonance, sextupole, storage-ring

2706

Y. Jiao, Z. Duan, G. Xu
IHEP, Beijing, People's Republic of China

Funding: Work supported by NSFC (11475202, 11405187, 11605212)
In a diffraction-limited storage ring (DLSR) light source, associated with the strong focusing and sextu-poles, the detuning terms are large and integer and half integer resonances can be reached at small momentum deviation and transverse amplitudes. We propose to use the effective ring acceptances of the bare lattice to characterize the nonlinear performance of the actual ring, by considering the limiting effects of integer and half integer resonances on beam dynamics. Such a concept will be very useful in lattice design of a DLSR light source. In this paper, we will discuss the reasoning, verification, and application range of this definition.

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WEPAB060

Design Study for the First Version of the HALS Lattice

lattice, storage-ring, sextupole, quadrupole

2713

Z.H. Bai, W. Li, L. Wang, P.H. Yang
USTC/NSRL, Hefei, Anhui, People's Republic of China

The Hefei Advanced Light Source (HALS) was proposed as a future soft X-ray diffraction-limited storage ring at NSRL. Recently the first version lattice of the HALS storage ring has been studied using a new lattice design concept that we proposed for diffraction-limited storage rings. In this new concept, the beta functions of each cell are made to be locally symmetric. In this paper, an 8BA lattice and a 6BA lattice are designed for the HALS with the first and the second kind of the new concept, respectively. In their nonlinear optimization, good dynamic aperture and momentum aperture can be easily obtained. Especially the dynamic momentum aperture can be larger than 7% or even 10%, which enables long beam lifetime and implementation of longitudinal injection scheme. The studied 6BA lattice is at present considered as the nominal HALS lattice of the first version.

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WEPAB069

Possible Suppression of Head-Tail Instability by a Feedback Kicker for a Light Source Without Any Sextupole

sextupole, storage-ring, dynamic-aperture, resonance

2738

T.-Y. Lee, B.H. Oh
PAL, Pohang, Kyungbuk, Republic of Korea

As storage ring based light sources pursue as low emittance as possible down to the diffraction limited number by adopting as many bending magnets and quadrupoles in a cell, the number of sextupole magnets required to correct chromaticity and secure a sufficiently big dynamic aperture grows substantially. As a result, the circumference of a multi-bend achromatic lattice storage ring is typically very long. This paper discusses over a possible scheme to run a storage ring without sextupole magnets at all and suppress the head-tail instability by using a transverse feedback kicker.

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WEPAB073

First Measurements of Pulse Picking by Resonant Excitation (PPRE) at the MAX IV 3 GeV Storage Ring

storage-ring, diagnostics, timing, feedback

2750

T. Olsson, Å. Andersson
MAX IV Laboratory, Lund University, Lund, Sweden

At synchrotron light storage rings there is demand for serving high-brilliance users requesting multibunch operation while simultaneously serving timing users who require single-bunch operation. One method to accomplish this is PPRE developed and currently in user operation at BESSY-II. In the method, the transverse emittance of one of the bunches in the bunch train is increased by an incoherent betatron excitation. Part of the light from this bunch can then be separated from the multibunch light by an aperture in the beamline, resulting in single-bunch light for the experiment. Methods such as this expand the scope of storage rings without requiring special fill patterns. This is of growing interest due to the upgrade trend towards diffraction-limited storage rings where it becomes more challenging to operate with inhomogeneous fill patterns. Measurements of PPRE were performed at the MAX IV 3 GeV storage ring utilizing the bunch-by-bunch feedback system both for excitation and as a diagnostic. Furthermore, measurements involving direct beam imaging at the diagnostics beamline allowed quantifying the effect of this excitation on the horizontal and vertical emittance.

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WEPAB075

First Optics and Beam Dynamics Studies on the MAX IV 3 GeV Storage Ring

storage-ring, injection, optics, synchrotron

2756

S.C. Leemann, Å. Andersson, M. Sjöström
MAX IV Laboratory, Lund University, Lund, Sweden

We present results from beam commissioning of the MAX IV 3 GeV storage ring as well as a summary of the beam dynamics studies that have so for been carried out. We report on injection and accumulation using a single dipole kicker, top-up injection, slow orbit feedback, restoring the linear optics to design, effects of in-vacuum undulators with closed gaps, and adjusting nonlinear optics to achieve design chromaticity correction as well as dynamic aperture sufficient for high injection efficiency and good Touschek lifetime.

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WEPAB086

Design and Optimisation of SPS-II Storage Ring

lattice, dipole, dynamic-aperture, undulator

2773

P. Klysubun, T. Pulampong, P. Sudmuang
SLRI, Nakhon Ratchasima, Thailand

Siam Photon Source (SPS) in Thailand has been operating and providing synchrotron radiation to users for more than a decade, leading to growing user community in South East Asia region. This gives rise to the possibility of constructing a new 3 GeV light source which could provide synchrotron light with higher photon energy and higher brilliance than the existing 1.2 GeV machine. Hybrid multi-bend achromat (HMBA) lattice design providing small natural beam emittance is a promising choice. In this paper, the Double-Triple Bend Achromat (DTBA) design with extra straight section scaled from Diamond Light Source upgrade lattice [ref.] is presented. Lattice optimisation with simplified magnet specifications still allows natural emittance of about 900 pm'rad for a 321.3 m circumference ring with sufficient dynamic aperture.

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WEPAB095

Electron Beam Commissioning of the DDBA Modification to the Diamond Storage Ring

injection, dipole, storage-ring, lattice

2800

I.P.S. Martin, M. Apollonio, C.P. Bailey, R. Bartolini, C. Christou, R.T. Fielder, M.J. Furseman, E. Koukovini-Platia, T. Pulampong, G. Rehm, W.A.H. Rogers, B. Singh
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

The Diamond storage ring has been modified by replacing one of the existing double bend achromat (DBA) cells with a double-DBA (DDBA) cell*. This change represents the largest modification to the storage ring since it was first commissioned in 2006, and was installed and fully commissioned during a single 8 week shutdown in autumn 2016. In view of this tight schedule, the planned commissioning steps and all high-level software needed to be developed and thoroughly tested in advance. Electron beam commissioning occupied the final 2 weeks of the shutdown, during which the injected electrons were captured and accumulated, the correct linear lattice was established, the nonlinear beam dynamics were studied, IDs were closed and the target 300 mA was achieved. This paper presents an overview of these activities.
* R.P. Walker et al., 'The Double-Double Bend Achromat (DDBA) Lattice Modification for the Diamond Storage Ring', Proc. IPAC 2014, MOPRO103, (2014)

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WEPAB096

Diamond Light Source: A 10-year View of the Past and Vision of the Future

cavity, vacuum, operation, feedback

2804

R.P. Walker, R. Bartolini, C. Christou, P. Coll, M.P. Cox, M.T. Heron, J. Kay, V.C. Kempson, S. Milward, G. Rehm
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

Diamond Light Source has been in regular operation for users for 10 years and so it is an appropriate moment to review the successes and challenges of the past, and also consider the vision for the next 10 years.

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WEPAB103

On-Axis Swap-Out Injection R+D for ALS-U

kicker, injection, alignment, storage-ring

2821

C. Steier, A. Anders, S. De Santis, T.H. Luo, T. Oliver, G.C. Pappas, C. Sun, C.A. Swenson, W.L. Waldron
LBNL, Berkeley, California, USA

Funding: This work is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The ALS-U upgrade promises to deliver diffraction limited performance throughout the soft x-ray range by lowering the horizontal emittance by a factor of 40 compared to the current ALS. One of the consequences of producing a small emittance is a small dynamic aperture, although the momentum acceptance will remain large enough for acceptable beam lifetime. To overcome this challenge, ALS-U will use on-axis swap-out injection to exchange bunch trains between the storage ring and an accumulator ring. On-axis swapout injection requires special fast pulsers and state-of-the-art stripline kicker magnets. This paper reports on the results of the on-axis swap-out injection R&D program, including beam tests of a complete stripline kicker/pulser system on the current ALS and the development of methods to speed up beam based commissioning after the upgrade shutdown.

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WEPAB104

Status of the Conceptual Design of ALS-U

lattice, kicker, storage-ring, vacuum

2824

C. Steier, A.P. Allézy, A. Anders, K.M. Baptiste, J.M. Byrd, K. Chow, G.D. Cutler, S. De Santis, R.J. Donahue, R.M. Duarte, J.-Y. Jung, S.C. Leemann, M. Leitner, T.H. Luo, H. Nishimura, T. Oliver, O. Omolayo, J.R. Osborn, G.C. Pappas, S. Persichelli, M. Placidi, G.J. Portmann, S. Reyes, D. Robin, F. Sannibale, C. Sun, C.A. Swenson, M. Venturini, W.L. Waldron, E.J. Wallén, W. Wan
LBNL, Berkeley, California, USA

Funding: This work is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The ALS-U upgrade promises to deliver diffraction limited performance throughout the soft x-ray range by lowering the horizontal emittance to about 50~pm resulting in 2-3 orders of brightness increase for soft x-rays compared to the current ALS. The design utilizes a multi bend achromat lattice with on-axis swap-out injection and an accumulator ring. One central design goal is to install and commission ALS-U within a short dark period. This paper summarizes the status of the conceptual design of the accelerator, as well as some results of the R&D program that has been ongoing for the last 3 years.

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WEPAB105

Design of the ALS-U Storage Ring Lattice

lattice, quadrupole, storage-ring, focusing

2827

C. Sun, J.-Y. Jung, H. Nishimura, D. Robin, F. Sannibale, C. Steier, C.A. Swenson, M. Venturini, W. Wan
LBNL, Berkeley, California, USA

Funding: The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
The Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory is proposing the upgrade of its synchrotron light source to reach soft x-ray diffraction limits within the present ALS footprint. The storage ring lattice design and optimization of this light source is one of the challenging aspects for this proposed upgrade. The candidate upgrade lattice needs not only to fulfill the physics design requirements such as brightness, injection efficiency and beam lifetime, but also to meet engineering constraints such as space limitations, maximum magnet strength as well as beamline port locations. In this paper, we will present the lattice design goals and choices and discuss the optimization approaches for the proposed ALS upgrade.

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WEPAB114

Potential Performance Limit of Storage Rings

storage-ring, quadrupole, sextupole, optics

2836

X. Huang
SLAC, Menlo Park, California, USA

The next generation of storage ring light sources will have significantly higher performance as multi-bend achromat cell structures are made practical with strong quadrupole and sextupole magnets. In principle the natural emittance can be made ever smaller with stronger magnets and larger rings until it reaches the true diffraction limit for hard X-rays. By considering the scaling laws of linear optics and nonlinear beam dynamics of storage rings and technical challenges, we explore the potential performance limit of future storage rings. A similar discussion may be applicable to the limit of energy frontier heavy-ion storage ring colliders.

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WEPAB116

LCLS Injector Laser Shaping and Applications

laser, electron, FEL, cathode

2844

S. Li, S.C. Alverson, D.K. Bohler, A.B. Egger, A.R. Fry, S. Gilevich, Z. Huang, A. Miahnahri, D.F. Ratner, J. Robinson, F. Zhou
SLAC, Menlo Park, California, USA

In the Linear Coherent Light Source (LCLS) at SLAC, the injector laser plays an important role as the source of the electron beam for the Free Electron Laser (FEL). The beam emittance and FEL performance are highly related to the transverse shape of the injector laser. When the injector laser has hot spots and non-uniformities that can carry over to the electron beam and degrade electron emittance and FEL performance, it requires long hours of manual adjustment by laser engineers and strenuous machine tuneup. The injector laser shaping project at LCLS aims to have precise control of the driver laser transverse profile in order to produce arbitrary electron beam profiles, which will enable us to study effects of laser shape on beam emittance and FEL performances. We use a digital micromirror device (DMD) to manipulate the drive laser profile. In this paper, we briefly discuss the implementations of laser shaping at LCLS. We demonstrate two applications of laser shaping. We present results of using laser shaping to control the X-ray laser output via an online optimizer. We also show the photocathode quantum efficiency measurements across cathode surface using the DMD.

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WEPAB125

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

cavity, linac, 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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WEPAB129

Study of Ionization Cooling with the MICE Experiment

solenoid, experiment, optics, detector

2874

C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

The international Muon Ionization Cooling Experiment (MICE) will demonstrate the ionization cooling of muons; the only known technique that can provide high brightness muon beams suitable for applications such as a Neutrino Factory or Muon Collider. MICE is underway at the Rutherford Appleton Laboratory and has recently taken the data necessary to characterise the physical processes that underlie the ionization-cooling effect. Measurements of the change in normalised transverse amplitude are presented in two configurations. The measurements of the ionization-cooling effect are discussed.

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WEPAB130

First Results from MICE Step IV

scattering, detector, simulation, solenoid

2878

P. Franchini
University of Warwick, Coventry, United Kingdom

Funding: STFC, DOE, NSF, INFN, CHIPP and more
Muon beams of low emittance provide the basis for the intense, well characterised neutrino beams of the Neutrino Factory and for lepton-antilepton collisions at energies of up to several TeV at a Muon Collider. The international Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling - the technique by which it is proposed to reduce the phase-space volume occupied by the muon beam. MICE is being constructed in a series of Steps. The configuration currently in operation at the Rutherford Appleton Laboratory is optimised for the study the properties of liquid hydrogen and lithium hydride that affect cooling. The data taken in the present configuration have been partially analyzed and the available results will be described in detail.
submitted by the Speakers Bureau of the collaboration, in charge of
finding later a member to prepare and present the contribution

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WEPAB131

Layout of the MICE Demonstration of Muon Ionization Cooling

betatron, detector, lattice, solenoid

2881

C. Hunt, J.-B. Lagrange, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Funding: STFC, DOE, NSF, INFN, CHIPP and more
Muon beams of low emittance provide the basis for the intense, well-characterised neutrino beams necessary to elucidate the physics of flavour at the Neutrino Factory and to provide lepton-antilepton collisions up to several TeV at the Muon Collider. The international Muon Ionization Cooling Experiment (MICE) will demonstrate muon ionization cooling, the technique proposed to reduce the phase-space volume occupied by the muon beam at such facilities. In an ionization-cooling channel, the muon beam traverses a material (the absorber) loosing energy, which is replaced using RF cavities. The combined effect is to reduce the transverse emittance of the beam (transverse cooling). The configuration of MICE required to deliver the demonstration of ionization cooling is presently being prepared in parallel to the execution of a programme designed to measure the cooling properties of liquid-hydrogen and lithium hydride (Step IV). The design of this final cooling demonstration will be presented together with a summary of the performance of each of its components and the cooling performance of the experiment.
submitted by the Speakers Bureau of the collaboration, in charge of
finding later a member to prepare and present the contribution

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WEPAB132

Research Program and Recent Results at the Argonne Wakefield Accelerator Facility (AWA)

wakefield, experiment, electron, acceleration

2885

M.E. Conde, S.P. Antipov, D.S. Doran, W. Gai, Q. Gao, G. Ha, C.-J. Jing, W. Liu, N.R. Neveu, J.G. Power, J.Q. Qiu, J.H. Shao, Y.R. Wang, C. Whiteford, E.E. Wisniewski, L.M. Zheng
ANL, Argonne, Illinois, USA
S.P. Antipov, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
Q. Gao, L.M. Zheng
TUB, Beijing, People's Republic of China
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
N.R. Neveu
IIT, Chicago, Illinois, USA
Y.R. Wang
IMP/CAS, Lanzhou, People's Republic of China

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357
We give an overview of the research program at the Argonne Wakefield Accelerator Facility (AWA), including some highlights of recent experiments. The AWA facility is dedicated to the study of beam physics and the development of technology for future particle accelerators. Two independent electron linacs are used to study wakefield acceleration: 70 MeV high charge electron bunches of up to 100 nC are used to drive wakefields, which can be probed by bunches originating from the same linac or from the 15 MeV linac. Recent Two-Beam-Acceleration (TBA) experiments operating at 11.7 GHz reached accelerating gradients of up to 150 MV/m. No indication of witness beam quality degradation was observed, and bunch charge was preserved during the acceleration process. Two identical TBA setups were used in series in order to demonstrate staging capabilities. Dielectric loaded structures operating at 26 GHz are also used in TBA experiments. Another main thrust of the research program consists of exploring and developing techniques to manipulate the phase space of electron bunches. These efforts include bunch shaping and the exchange of emittances in the transverse and the longitudinal phase spaces

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WEPAB133

A Wedge Absorber Experiment at MICE

collider, experiment, optics, scattering

2888

D.V. Neuffer
Fermilab, Batavia, Illinois, USA
T.A. Mohayai
IIT, Chicago, Illinois, USA
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA
D.J. Summers
UMiss, University, Mississippi, USA

Emittance exchange mediated by wedge absorbers is required for longitudinal ionization cooling and for final transverse emittance minimization for a muon collider. A wedge absorber within the MICE beam line could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders, as well as configurations for low-energy muon sources. Parameters for this test are explored in simulation and possible experimental configurations with simulated results are presented.

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WEPAB134

Progress on Beam-Plasma Effect Simulations in Muon Ionization Cooling Lattices

plasma, simulation, scattering, electron

2891

J.S. Ellison
IIT, Chicago, Illinois, USA
P. Snopok
Fermilab, Batavia, Illinois, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: Work supported by the U.S. Department of Energy.
New computational tools are essential for accurate modeling and simulation of the next generation of muon-based accelerators. One of the crucial physics processes specific to muon accelerators that has not yet been simulated in detail is beam-induced plasma effect in liquid, solid, and gaseous absorbers. We report here on the progress of developing the required simulation tools and applying them to study the properties of plasma and its effects on the beam in muon ionization cooling channels.

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WEPAB135

Novel Implementation of Non-parametric Density Estimation in MICE

experiment, lattice, beam-cooling, solenoid

2895

T.A. Mohayai
IIT, Chicago, Illinois, USA
D.V. Neuffer, P. Snopok
Fermilab, Batavia, Illinois, USA
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC05-06OR23100.
Cooled muon beams are essential to enable future Neutrino Factory and Muon Collider facilities. The international Muon Ionization Cooling Experiment (MICE) aims to demonstrate muon beam cooling through ionization energy loss in material. A figure of merit for muon cooling in MICE is the transverse root-mean-square (RMS) emittance reduction and to measure this, the individual muon positions and momenta are reconstructed using two scintillating-fiber tracking detectors housed in spectrometer solenoid modules. The reconstructed positions and momenta before and after a low-Z absorbing material are then used for constructing the covariance matrix and measuring normalized transverse RMS emittance of MICE muon beam. In this study, the direct measurement of phase-space density and volume as measures of the efficacy of muon beam cooling in MICE, using the density estimation techniques is described.

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WEPIK006

Cancellation of the Leak Field from Lambertson Septum for the Beam Abort System in the SuperKEKB

quadrupole, coupling, sextupole, septum

2918

N. Iida, M. Kikuchi, K. Kodama, T. Mimashi, T. Mori, Y. Ohnishi, K. Oide, H. Sugimoto, M. Tawada
KEK, Ibaraki, Japan

The first commissioning of SuperKEKB, Phase 1, was performed from February 2016 for five months. A Lambertson septum magnet is utilized to vertically extract the aborted beam, kicked by the horizontal abort kickers upstream into a beam dump. This magnet creates unexpected leak field with a non-negligible skew quadrupole component to the stored beam. Two kinds of skew quadrupole magnets are installed on both sides of the Lambertson septum. One is additional skew windings on the sextupole magnet, and the other is a skew quadrupole magnet with permanent magnets. This paper will report that the cancellations of the leak fields was successful and useful for optics correction.

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WEPIK013

Electron Beam Injection Septum

injection, septum, electron, synchrotron

2943

T. Mori, N. Iida, M. Kikuchi, T. Mimashi, Y. Sakamoto, S. Takasaki, M. Tawada
KEK, Ibaraki, Japan

The SuperKEKB project is in progress toward the initial physics run in autumn 2018. It assumes the nano-beam scheme, in which the emittance of the colliding beams is 4.6 nm. To achieve such a low emittance, it is vitally important to preserve the emittance during the transport of the beam from the linac to the main ring. One of the most difficult sections is the injection system. Since the dynamic aperture is small for the low emittance, the allowed distances between the stored beam and the injected beam at the injection point are 7.8 mm for the betatron injection and 7.2 mm for the synchrotron injection. The new septum magnets has been constructed and installed in the beam line after the measurement of magnetic flux density and aging test. It has been also checked the septum magnets are capable of design orbit. The initial beam injection succeeded on schedule and they had been operated without any big troubles in the first beam run of Phase-1.

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WEPIK014

Coupled Bunch Instability and Its Cure at J-PARC RCS

impedance, kicker, space-charge, injection

2946

Y. Shobuda, H. Harada, H. Hotchi, P.K. Saha, T. Takayanagi, F. Tamura, N. Tani, T. Togashi, Y. Watanabe, K. Yamamoto, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y.H. Chin, Y. Irie, T. Toyama
KEK, Ibaraki, Japan

The RCS at J-PARC is a kicker-impedance dominant machine, which violates the impedance budget from a classical viewpoint. Nevertheless, we have recently succeeded to accelerate a 1-MW equivalent beam by making maximum use of the space charge effect on the beam instabilities. In this report, we explain the manipulation to suppress the beam instability, at first. Then, we discuss some issues to suppress the beam instabilities for beams with much smaller transverse emittance, as well as the present status of our efforts to reduce the kicker impedance toward the realization of the higher beam power at the RCS.

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WEPIK015

Optimized Monochromatization for Direct Higgs Production in Future Circular e⁺e⁻ Colliders

collider, luminosity, radiation, electron

2950

F. Zimmermann
CERN, Geneva, Switzerland
M.A. Valdivia García
DCI-UG, León, Mexico

Funding: This work was supported in part by the European Commission under the HORIZON2020 Integrating Activity project ARIES, grant agreement 730871, and by the Mexican CONACyT ‘‘BEAM'' Programme.
Direct s-channel Higgs production in e⁺e⁻ collisions is of interest if the centre-of-mass energy spread can be reduced to be comparable to the width of the standard model Higgs boson. A monochromatization scheme could be employed in order to achieve the desired reduction, by introducing a non-zero horizontal dispersion of opposite sign for the two colliding beams at the interaction point. In high-energy high-luminosity circular colliders, beamstrahlung may increase the energy spread and bunch length. The horizontal emittance blow up due to beamstrahlung, a new effect not present in past monochromatization proposals, may degrade the performance, especially the luminosity. We study, for the FCC-ee at 62.5 GeV beam energy, how we can optimize the IP optics parameters (betax*, Dx*) along with the number of particles per bunch so as to obtain maximum luminosity at a desired target value of the collision energy spread.

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WEPIK018

Optics Design for Cepc Double Ring Scheme

lattice, interaction-region, optics, sextupole

2962

Y. Wang, T.J. Bian, J. Gao, H. Geng, B. Sha, D. Wang, C.H. Yu, Y. Zhang
IHEP, Beijing, People's Republic of China
F. Su
Institute of High Energy Physics (IHEP), People's Republic of China

CEPC is a future Circular Electron and Positron Collider proposed by China to mainly study the Higgs boson. Its baseline scheme is double ring scheme and alternative scheme is partial double ring scheme. This paper will present the optics design for the main ring of double ring scheme. CEPC will also work as W and Z factories. Compatible optics design for W and Z mode will be presented as well.

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WEPIK031

Challenges and Status of the Rapid Cycling Top-Up Booster for FCC-ee

collider, booster, injection, synchrotron

2996

B. Härer, S. Aumon, B.J. Holzer, Y. Papaphilippou, T. Tydecks
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

FCC-ee is a 100 km e⁺ e⁻ collider, which is being designed within the Future Circular Collider Study (FCC) for precision studies and rare decay observations in the range of 90 to 350 GeV center-of- mass energy. The beam lifetime will be limited to less than one hour, because of radiative Bhaba scattering and beamstrahlung. In order to keep the luminosity on the high level of 10³⁵ cm^-2s^-1 continuous top-up injection is required. Therefore, besides the collider, that will operate at constant energy, a fast cycling booster synchrotron will be installed in the tunnel. The injection energy to the booster synchrotron will be around 6-20 GeV. Such a small energy together with the large bending radius not only creates an ultra-small beam emittance, but also requires very low magnetic fields close to the limit of technical feasibility. This paper will focus on the challenges and requirements for the top-up booster design arising from low magnetic fields and collective instabilities and present the status of the lattice design.

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WEPIK034

Progress in the FCC-ee Interaction Region Magnet Design

solenoid, detector, quadrupole, interaction-region

3003

M. Koratzinos, A.P. Blondel
DPNC, Genève, Switzerland
M. Benedikt, F. Zimmermann
CERN, Geneva, Switzerland
E.R. Bielert
University of Illinois at Urbana-Champaign, Illinois, USA
A.V. Bogomyagkov, S.V. Sinyatkin, P. Vobly
BINP SB RAS, Novosibirsk, Russia
M. Boscolo
INFN/LNF, Frascati (Roma), Italy
M. Dam
NBI, København, Denmark
K. Oide
KEK, Ibaraki, Japan

The design of the region close to the interaction point of the FCC-ee experiments is especially challenging. The beams collide at an angle (±15mrad) in a region where the detector solenoid magnetic field is large. Moreover, the very low vertical β^* of the machine necessitates that the final focusing quadrupoles are also inside this high field region. The beams should be screened from the effect of the detector solenoid field, and the emittance blow-up due to vertical dispersion in the interaction region should be minimized while leaving enough space for detector components. Crosstalk between the two final focus quadrupoles, only about 6 cm apart at the tip, should also be minimized. We present an update on the subject.

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WEPIK041

Update on the JLEIC Electron Collider Ring Design

sextupole, electron, lattice, ion

3018

Y.M. Nosochkov, Y. Cai, M.K. Sullivan
SLAC, Menlo Park, California, USA
Y.S. Derbenev, F. Lin, V.S. Morozov, F.C. Pilat, G.H. Wei, Y. Zhang
JLab, Newport News, Virginia, USA
M.-H. Wang
Self Employment, Private address, USA

Funding: Authored by Jefferson Science Associates, LLC under US DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported by the US DOE Contract DE-AC02-76SF00515.
We present an update on the lattice design of the electron ring of the Jefferson Lab Electron-Ion Collider (JLEIC). The electron and ion collider rings feature a unique figure-8 layout providing optimal conditions for preservation of beam polarization. The rings include two arcs and two intersecting long straight sections containing a low-beta interaction region (IR) with special optics for detector polarimetry, electron beam spin rotator sections, ion beam cooling sections, and RF-cavity sections. Recent development of the electron ring lattice has been focused on minimizing the beam emittance while providing an efficient non-linear chromaticity correction and large dynamic aperture. We describe and compare three lattice designs, from which we determine the best option.

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WEPIK043

Modeling Local Crabbing Dynamics in the JLEIC Ion Collider Ring

ion, lattice, cavity, luminosity

3022

S.I. Sosa Guitron, J.R. Delayen
ODU, Norfolk, Virginia, USA
V.S. Morozov
JLab, Newport News, Virginia, USA

The Jefferson Lab Electron-Ion Collider (JLEIC) design considers a 50 mrad crossing angle at the Interaction Point. Without appropriate compensation, this could geometrically reduce the luminosity by an order of magnitude. A local crabbing scheme is implemented to avoid the luminosity loss: crab cavities are placed at both sides of the interaction region to restore a head-on collision scenario. In this contribution, we report on the implementation of a local crabbing scheme in the JLEIC ion ring. The effects of this correction scheme on the stability of proton bunches are analyzed using the particle tracking software elegant.

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WEPIK050

Parameters for eRHIC

luminosity, electron, proton, synchrotron

3038

R.B. Palmer, C. Montag
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Requirements for the proposed BNL eRHIC Ring-Ring Electron Ion Collider (EIC) are discussed, together with the dependence of luminosity with the beam divergence and forward proton acceptance. Parameters are given for four cases. The first two use no cooling and could represent a first phase of operation. The next two use strong cooling and increased beam currents. In each case parameters are given that 1) meets the requirement for forward proton acceptance, and 2) has somewhat higher divergences giving somewhat higher luminosity.

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WEPIK065

Research Activities Towards a Conversion of PETRA III Into a Diffraction Limited Synchrotron Light Source

lattice, sextupole, synchrotron, photon

3077

R. Wanzenberg, I.V. Agapov, K. Balewski, M. Bieler, W. Brefeld, R. Brinkmann, M. Dohlus, H. Ehrlichmann, X.N. Gavaldà, J. Keil, M. Körfer, G.K. Sahoo, C.G. Schroer, E. Weckert
DESY, Hamburg, Germany
M. Eriksson
MAX IV Laboratory, Lund University, Lund, Sweden

At DESY the Synchrotron Light Source PETRA III offers scientists outstanding opportunities for experiments with hard X-rays of exceptionally high brilliance since 2009. Research activities have been started towards a future upgrade scenario of PETRA III which envisions the conversion of the PETRA ring into a ultra-low emittance hard X-ray radiation source: PETRA IV. The lattice design is aiming for a horizontal emittance in the range between 10 pm rad and 30 pm rad at a beam energy of 6 GeV. Two different approaches have been considered for the lattice design: a design based on a hybrid multibend achromat with an interleaved sextupole configuration based on the ESRF design, and a lattice with a non-interleaved sextupole configuration with a special phase space exchange configuration. We are reporting the current status of the design activities including studies related to the injector.

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WEPIK074

Twiss Parameter Measurement and Application to Space Charge Dynamics

resonance, betatron, space-charge, lattice

3101

K. Ohmi, S. Igarashi, T. Toyama
KEK, Ibaraki, Japan
H. Harada, S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan
N. Kuroo
UTTAC, Tsukuba, Ibaraki, Japan
Y. Sato
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
R. Tomás, A. Wegscheider
CERN, Geneva, Switzerland

We are looking for feasible and quantitative method to evaluate space charge induced beam loss in J-PARC MR. One possible way is space charge simulation and theory based on measured Twiss parameter. Twiss parameter measurement using turn-by-turn monitors is presented. Resonance strengths of lattice magnets and space charge force are estimated by the measured Twiss parameters. Emittance growth and beam loss under the resonance strengths are discussed.

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WEPIK077

Shielding of Beam Pipe on Rapidly Varying Magnetic Field

simulation, vacuum, shielding, feedback

3107

N. Wang, J. Chen, S.K. Chen, P. He, G. Xu
IHEP, Beijing, People's Republic of China

In low emittance rings, beam is quite sensitive to orbit oscillations. Fast correctors will be used to correct the beam orbit. The fast varying magnetic field will generate eddy current on the beam pipe, which will in turn change the phase and the amplitude of the magnetic field. The shielding effect of the beam pipe on a fast varying magnetic field is simulated for different frequencies. The results are also benchmarked with the measurements in the lab.

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WEPIK097

An Optimization Tool to Design a Coreless Non-Linear Injection Kicker Magnet

injection, kicker, target, sextupole

3170

B. MacDonald-de Neeve
ETH, Zurich, Switzerland
B. MacDonald-de Neeve, M. Paraliev, A. Saá Hernández
PSI, Villigen PSI, Switzerland

Top-up injection into low emittance light sources is challenging due to their inherent small dynamic apertures (DA). The use of a multipole-magnet injection kicker prevents disturbing the circulating beam. However, the injected bunch will be mismatched due to unwanted focusing (linear field profile) or even filamented (nonlinear field profile). Coreless nonlinear kicker magnets, using different configurations of straight conductors, can produce transverse step-like magnetic field distribution which prevent the mismatch. We explored an 8-conductor configuration and a multi-conductor approach like unipolar massless septum design. Maximizing the spatial derivative of the transverse field step function is crucial in order to kick the injected bunch inside the DA. Comparing the results of different designs a particular dependence between the smallest clear aperture and the maximum transverse field spatial derivative was observed. We have developed an optimization tool to generate arbitrary 2D magnetic fields and determine the associated current distribution. With it we obtained new design solutions for possible injection magnets that go beyond the limitations of the standard designs.

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WEPVA005

Simulation of a Many Period Dielectric Grating-based Electron Accelerator

laser, electron, simulation, acceleration

3256

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

Funding: GBMF - Gordon and Betty Moore Foundation
Dielectric laser driven particle accelerators have become a research area of major interest due to the high acceleration gradients achievable. Those are mainly attributed to the high damage thresholds of dielectrics at optical frequencies. Simulations of these structures are usually computed with Particle-In-Cell (PIC) codes. Their accuracy and self consistency comes with a major drawback of high computation costs. Computation of structures consistent of hundreds to thousands of periods are only viable with High Performance Computing clusters. In this proceeding a compromise of CST* PIC simulations combined with a transfer function model is presented to simulate relativistic electron accelerators for particle energies up to the GeV regime or higher. In addition a simplified example accelerator design is investigated and the required electron bunch parameters from a sub-relativistic source are computed.
*CST - Computer Simulation Technology, available from www.
cst.com.

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WEPVA008

Beam Dynamics in THz Dielectric Loaded Waveguides for the AXSIS Project

linac, gun, injection, 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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WEPVA021

Phase Space Manipulation of Sub-Picosecond Electron Bunches Using Dielectric Wakefield Structures

wakefield, FEL, simulation, electron

3302

T.H. Pacey, G.X. Xia
UMAN, Manchester, United Kingdom
D.J. Dunning, Y.M. Saveliev
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Dielectric lined waveguides have drawn interest due to their application as high gradient accelerating structures, in both externally driven and wakefield schemes. We present simulation studies of sub-picosecond electron bunches interacting with dielectric structures in the self-wake regime. The parameter space for a tunable, sub-millimeter aperture, terahertz frequency structure is investigated. The potential application as a longitudinal phase space dechirper is demonstrated, with specific application to CLARA at Daresbury Laboratory. The impact of transverse effects is considered and minimised. The resulting FEL output is simulated.

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WEPVA037

Machine Development Studies in the CERN PS Booster, in 2016

injection, extraction, booster, space-charge

3339

E. Benedetto, S.C.P. Albright, M.E. Angoletta, W. Bartmann, J.M. Belleman, A. Blas, M. Cieslak-Kowalska, G.P. Di Giovanni, A. Findlay, V. Forte, A. Garcia-Tabares, G. Guidoboni, S. Hancock, M. Jaussi, B. Mikulec, J.C. Molendijk, A. Oeftiger, T.L. Rijoff, F. Schmidt, P. Zisopoulos
CERN, Geneva, Switzerland
M. Cieslak-Kowalska
EPFL, Lausanne, Switzerland
P. Zisopoulos
Uppsala University, Uppsala, Sweden

The paper presents the outstanding studies performed in 2016 in preparation of the PS Booster upgrade, within the LHC Injector Upgrade project (LIU), to provide twice higher brightness and intensity to the High-Luminosity LHC. Major changes include the increase of injection and extraction energy, the implementation of a H⁻ charge-exchange injection system, the replacement of the present Main Power Supply and the deployment of a new RF system (and related Low-Level), based on the Finemet technology. Although the major improvements will be visible only after the upgrade, the present machine can already benefit of the work done, in terms of better brightness, transmission and improved reproducibility of the present operational beams. Studies address the space-charge limitations at low energy, for which a detailed optics model is needed and for which mitigation measurements are under study, and the blow-up reduction at injection in the downstream machine, for which the beams need careful preparation and transmission. Moreover they address the requirements and the reliability of new beam instrumentation and hardware that is being installed in view of LIU.

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WEPVA038

Tail Repopulation Measurements in the PSB

kicker, simulation, injection, experiment

3343

E. Benedetto, M. Cieslak-Kowalska, P. Zisopoulos
CERN, Geneva, Switzerland
M. Cieslak-Kowalska
EPFL, Lausanne, Switzerland

The PS Booster (PSB) is the first circular accelerator in the LHC injector chain providing protons for the full CERN complex. Each of its four rings provides beams in a range of intensities varying from 40 e11 p/cycle to 0.8 e13 p/cycle. Low intensity beams are produced by transverse shaving, that is by scraping the tails, in order to tailor the intensity and transverse emittances. Eventually, tails repopulate and the beam profile reshapes, under the effect of space charge, which is dominant at low energy in the PS Booster. This paper describes the results of the measurements after the shaving process, where the tails are scraped but finally re-appear in the transverse profile, and it provides a first benchmark with space-charge simulations. It highlights the challenges encountered and the lessons learned, to guide the future experiments. The final outcome of these studies is the characterisation of the halo creation mechanism and the determination of the diffusion speed, important for the design of the future PS Booster scraping system.

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WEPVA039

Transition Crossing in the Main Injector for PIP-II

simulation, lattice, booster, operation

3347

R. Ainsworth, S. Chaurize, I. Kourbanis, E.G. Stern
Fermilab, Batavia, Illinois, USA

Proton Improvement Plan-II (PIP-II) is Fermilab's plan for providing powerful, high-intensity proton beams to the laboratory's experiments. PIP II will include upgrades to the Booster, Recycler and Main Injector which will be required to accelerate 50% more beam as well as increasing the Booster repetition rate from 15 to 20 Hz. To accommodate the faster rate, the momentum separation of the slip stacking beams in the Recycler must increase which will result in in larger longitudinal emittance bunches in MI. In order to cross transition without losses, it is expected a gamma-t jump will be needed. Gamma-t jump schemes for the MI are investigated.

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WEPVA041

Rematching AGS Booster Synchrotron Injection Lattice for Smaller Transverse Beam Emittances

booster, injection, proton, quadrupole

3353

C. Liu, J. Beebe-Wang, K.A. Brown, C.J. Gardner, H. Huang, M.G. Minty, V. Schoefer, K. Zeno
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The polarized proton beam is injected into the booster via the charge-exchange (H⁻ to H⁺) scheme. The emittance growth due to scattering at the stripping foil is proportional to the beta functions at the foil. It was demonstrated that the current scheme of reducing the beta functions at the stripping foil preserves the emittance better, however the betatron tunes are above but very close to half integer. Due to concern of space charge and half integer in general, options of lattice designs aimed towards reducing the beta functions at the stripping foil with tunes at more favorable places are explored.

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WEPVA053

New Extraction Line for the Lns Cyclotron

extraction, cyclotron, ion, quadrupole

3378

L. Calabretta, A. Calanna, G. D'Agostino, D. Rifuggiato, A.D. Russo
INFN/LNS, Catania, Italy
G. D'Agostino
Universita Degli Studi Di Catania, Catania, Italy

The LNS Superconducting Cyclotron will be modified to allow the extraction by stripper of ion beams with power up to 10 kW. By choosing properly the position of the stripper foils and of the corrector magnetic channels, it is possible to convoy the trajectories of the selected representative ion beams across a new extraction channel. It is mandatory to design a new extraction line to transport these beams to the existing beam transport line. The extracted beams have an energy spread of about ±0.4%, so, the new extraction line has to compensate the correlation energy-position of the beam and to produce an achromatic waist of the beam at the common starting point of the existing transport lines. The main changes of the cyclotron will be briefly described and the performance and the features of the new extraction line will be presented too.

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WEPVA055

Pre Orbit Correction Based on Tunnel Level Measurement in SuperKEKB

alignment, optics, coupling, factory

3385

A. Morita, H. Koiso, Y. Ohnishi, H. Sugimoto
KEK, Ibaraki, Japan

The SuperKEKB accelerator tunnel has about 30mm displacement in the vertical direction. From the result of optics correction simulation with the tunnel displacement, it was decided that the beamline components align against the smoothed line of the measured tunnel level in order to save the alignment cost and time. In order to compensate the large tunnel displacement, the pre orbit correction based on the tunnel level measurement is applied at the beginning of the phase-1 commissioning, and the beam circulation is achieved with the small number of magnet adjustments. We report the result of the pre orbit correction.

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WEPVA120

Beam Dynamics Simulation for EPU200 in TPS

electron, storage-ring, undulator, simulation

3551

M.-S. Chiu, C.H. Chen, J.Y. Chen, P.J. Chou, T.Y. Chung, Y.-C. Liu, F.H. Tseng
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) is a low-emittance 3-GeV light source at Natioal Synchrotron Radiation Research Center (NSRRC). Five in-vacuum undulator beamlines were delivered to users on Sep. 22, 2016. To generate 10 ~ 500 eV photon with variuos polarizations, users proposed a new EPU : EPU200. In this paper, we present the preliminary results of beam dynamics simulation for EPU200.

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WEPVA147

Iron-Free Detector System for the Linear Collider with Multiple Return Solenoids

solenoid, detector, collider, linear-collider

3615

A.A. Mikhailichenko
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

We investigate the Iron-free magnetic system for implementation in a detector for future Linear Collider. One peculiarity is in usage of many small-diameter solenoids for the flux return. Machine-detector interface is discussed also.

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THOBA3

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

positron, damping, linac, 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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THPPA3

Hybrid Multi Bend Achromat: from SuperB to EBS

lattice, dipole, luminosity, synchrotron

3670

P. Raimondi
ESRF, Grenoble, France

The Hybrid Multi Bend Achromat: from SuperB to EBS. The motivations and rationale at the basis of the Hybrid Multi Bend Achromat (HMBA) lattice and its evolution through the years are presented. Its implementation in the ESRF Extremely Brilliant Source (EBS) upgrade is also shown.

Slides THPPA3 [24.610 MB]

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THPAB009

Multi-Objective Optimization of an SRF Photoinjector for ERL and UED Applications

gun, laser, electron, SRF

3704

E. Panofski, A. Jankowiak, T. Kamps, G. Kourkafas
HZB, Berlin, Germany
S. Eisebitt
MBI, Berlin, Germany

Superconducting RF photoinjectors, running in continuous-wave (cw) mode, are able to generate electron beams of high average brightness and ultra-short bunches. Therefore, they satisfy the requirements of future accelerator facilities, such as energy recovery linacs (ERL). Further, SRF guns are able to provide relativistic probe beams for ultrafast electron diffraction (UED). Choosing suitable values for the drive laser, cavity and solenoid settings poses a great challenge for the injector commissioning and operation. Using multi-objective optimization based on an evolutionary algorithm, optimum gun parameter settings are extracted from Pareto-optimum solutions. The development of a universal multi-objective optimization algorithm for SRF photoinjectors as well as first Pareto optimum results for an ERL and UED application of GunLab, the compact SRF gun test facility at Helmholtz-Zentrum Berlin, will be presented.

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THPAB017

Investigation of High Repetition Rate Femtosecond Electron Diffraction at PITZ

electron, laser, gun, experiment

3727

H.J. Qian, M. Groß, M. Krasilnikov, A. Oppelt, F. Stephan
DESY Zeuthen, Zeuthen, Germany

PITZ is a photoinjector test facility for FLASH and European XFEL, and it has been proposed to be a prototype machine to develop an accelerator based THz/IR source for European XFEL pump-probe experiment. In addition, the machine can also support femtosecond electron diffraction at the same beam repetition rate as European XFEL, which brings XFEL users more flexibility for different experiments. In this paper, a femtosecond electron diffraction scheme based on the PITZ accelerator setup is investigated.

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THPAB023

The Influence of Initial Current Density Distribution on the Emittance Reduction

cathode, gun, electron, flattop

3744

H. Yamashita, T. Kii, K. Masuda, K. Nagasaki, T. Nogi, H. Ohgaki, K. Torgasin, H. Zen
Kyoto University, Kyoto, Japan

In this study, the influence of current density distribu-tion on the cathode surface on the beam emittance evolution was investigated. The emittance evolution with different beam profiles (flat-top, peak and hollow distribution) have been compared. The modification of the current profile was shown to affect the axial distance of the point of minimal emittance over wide range. The hollow profile allows extending the axial distance of the point of emittance minimum keeping its value extremely low. Further the parameters of a peak profile, which give the smallest emittance were determined. This work demonstrates the significance of initial current density distribution for the emittance evolution.

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THPAB024

Emittance Growth at Charge-Exchanging Multi-Turn Injection in KURRI FFAG

injection, acceleration, scattering, simulation

3747

T. Uesugi, Y. Ishi, Y. Kuriyama, Y. Mori
Kyoto University, Research Reactor Institute, Osaka, Japan

In the fixed field alternating gradient (FFAG) synchrotron in Kyoto university research reactor institute (KURRI), rapid beam loss of factor 100 is observed right after the injection. In the synchrotron, charge-exchanging multi-turn injection is adopted with a stripping foil located on the closed orbit of the injection energy. No bump orbit system is used and the injected beams escape from the foil according to the closed-orbit shift by acceleration. The particles hit the foil many times and that is why the emittance grows up during the injection. In this paper, simulation studies are done to estimate the emittance growth and beam losses. The scattering effect at the foil is modeled by GEANT4.

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THPAB026

Feasibility Analysis of Emittance Preservation During Bunch Compression in the Presence of Coherent Synchrotron Radiation in an Arc

dipole, simulation, lattice, synchrotron

3753

X.Y. Huang, X. Cui, S. Gu, Y. Jiao, G. Xu
IHEP, Beijing, People's Republic of China

Electron beam with low transverse emittance, short bunch length and high peak current is the basic requirement in modern high-brightness light sources. However, coherent synchrotron radiation (CSR) will dilute the transverse emittance when the electron beams pass through a magnetic bunch compressor and degrade the performance of the machine. In this paper, based on our CSR point-kick analysis, arc compressors with high compression factor in the presence of CSR effect are studied, both periodic and aperiodic arcs are included. Through analytical and numerical research, an easy optics design technique is introduced to minimize the emittance dilution within these compressors. Taking practical considerations into account, the results of periodic and aperiodic arcs are compared.

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THPAB027

Symplectic Multi-Particle Tracking Using Cuda

GPU, space-charge, simulation, kicker

3756

Zh.C. Liu
IHEP, Beijing, People's Republic of China
J. Qiang
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and the Ministry of Science and Technology of China under Grant No.2014CB845501.
The symplectic tracking model can preserve phase space structure and reduce non-physical effects in long term simulation. Though this model is computationally expensive, it is very suitable for parallelization and can be accelerated significantly by using Graphic Processing Units (GPUs). Using a single GPU, the code achieves a speedup of more than 400 compared with the time on a single CPU core. It also shows good scalability on a GPU cluster at Oak Ridge Leadership Computing Facility. In this paper, we report on the GPU code implement, the performance test on both single-GPU and multi-GPU cluster, and an application of beam dynamics simulation.

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THPAB032

Estimates of Collective Effects in the HALS Storage Ring Having the First Version Lattice

impedance, coupling, storage-ring, lattice

3770

N. Hu, Z.H. Bai, W. Li, Q. Luo, L. Wang
USTC/NSRL, Hefei, Anhui, People's Republic of China

The Hefei Advanced Light Source (HALS) is a diffraction-limited storage ring with a beam energy of 2.0 GeV. Recently the first version lattice has been designed for the HALS storage ring, and the natural emittance is about 18 pm·rad. In this paper, we study the collective effects in this storage ring, including calculations of intra-beam scattering effect and Touschek lifetime, and estimates of the thresholds of some single-bunch and multi-bunch instabilities.

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THPAB042

Long-Range Beam-Beam Orbit Effects in LHC, Simulations and Observations From Machine Operation in 2016

luminosity, simulation, operation, closed-orbit

3799

A.A. Gorzawski, K. Fuchsberger, M. Hostettler, T. Pieloni, J. Wenninger
CERN, Geneva, Switzerland

To limit the number of head on collisions to only one at the interaction point in the Large Hadron Collider (LHC), two beams are colliding with a non zero crossing angle. Under the presence of such angle the closed orbits of the individual bunches in the bunch train varies due to the long-range beam-beam effects. These variations leave a signature as a non zero transverse offset at the collision points visible in the front and trail of the bunch train. When operation team aims for the optimised beam orbit and therefore maximised luminosity, those front and tail bunches due to the overall offset experience reduced luminosity. This paper describes an overview of the existing tool for simulating these effects and compares to operational data. The effects of different operational scenarios (i.e. beam brightness, reduced or asymmetric crossing angles between the interaction points etc.) are simulated and discussed.

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THPAB044

Development of Computational Tools for Noise Studies in the LHC

simulation, GPU, Windows, beam-beam-effects

3807

S. Kostoglou, N. Karastathis, Y. Papaphilippou, D. Pellegrini, P. Zisopoulos
CERN, Geneva, Switzerland
P. Zisopoulos
Uppsala University, Uppsala, Sweden

Noise can have a significant impact on the beam dynamics in the LHC, enhancing diffusion processes and leading to emittance blowup. In order to study the details of such effects with computer simulations, a new set of tools is being developed. In particular, a demonstrator GPU-based particle tracker has been built profiting from the technology provided by the NVRTC Cuda library. Its performances for short term beam dynamic simulations in presence of many macro particles are highly promising. In addition, the Numerical Analysis of Fundamental Frequencies (NAFF) algorithm has been thoroughly inspected. Several alternatives to its fundamental steps have been investigated in a modern C++ implementation. The method was also used to produce Frequency Maps and benchmark these tools with other simulations.

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THPAB055

Modelling of Curvilinear Electrostatic Multipoles in the Fermilab Muon g-2 Storage Ring

multipole, quadrupole, storage-ring, lattice

3837

A.T. Herrod, S. Jones, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
I.R. Bailey, A.T. Herrod, S. Jones, M. Korostelev, A. Wolski
Cockcroft Institute, Warrington, Cheshire, United Kingdom
I.R. Bailey, M. Korostelev
Lancaster University, Lancaster, United Kingdom

Funding: This research was funded by the STFC Cockcroft Institute Core grants no. ST/G008248/1 and ST/P002056/1.
The Fermilab Muon g-2 Experiment (E989) contains flat-plate electrostatic quadrupoles, curved with the reference trajectory as defined by the constant, uniform magnetic dipole field. To understand the beam behaviour at a sufficient level, we require fast, high-accuracy particle tracking methods for this layout. Standard multipole fits to numerically calculated 2D transverse electric field maps have provided a first approximation to the electric field within the main part of the quadrupole, but cannot model the longitudinal curvature or extended fringe fields of the electrostatic plates. Expressions for curvilinear multipoles can be fit to a 2D transverse slice taken from the central point of a numerically calculated 3D electric field map of the quadrupole, providing a curved-multipole description. Generalised gradients can be used to model the fringe field regions. We present the results of curvilinear multipole and generalised gradient fits to the curved quadrupole fields, and the differences in tracking using these fields over 200 turns of a model of the storage ring in BMAD.

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THPAB056

Dynamic Aperture Studies of the Long-Range Beam-Beam Interaction at the LHC

simulation, luminosity, dynamic-aperture, coupling

3840

M.P. Crouch, R.B. Appleby
UMAN, Manchester, United Kingdom
J. Barranco García, T. Pieloni, C. Tambasco
EPFL, Lausanne, Switzerland
X. Buffat, M. Giovannozzi, E.H. Maclean
CERN, Geneva, Switzerland
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Long-range beam-beam interactions dictate the choice of operational parameters for the LHC, such as the crossing angle and β^* and therefore the luminosity reach for the collider. These effects can lead to particle losses, closed orbit effects and emittance growth. Defining how these effects depend on the beam-beam separation will determine the minimum crossing angle and the β^* the LHC can operate. In this article, analysis from a dedicated machine study is presented in which the crossing angle was reduced in steps and the impact on beam intensity and luminosity lifetimes were observed. Based on the observations during the machine study, the intensity decays are compared to expectations from models. Estimates of the luminosity reach in the LHC are also computed.

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THPAB061

Limiting Effects in the Double EEX Beamline

shielding, timing, simulation, dipole

3858

G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
M.E. Conde, D.S. Doran, J.G. Power
ANL, Argonne, Illinois, USA

Funding: This work is supported by Department of Energy, Office of High Energy Physics, under Contract No. DE-AC02-06CH11357.
The double emittance exchange (EEX) beamline is suggested to overcome the large horizontal emittance and transverse jitter issues associated with the single EEX beamline while preserving its powerful phase-space manipulation capability. However, the double EEX beamline also has potential limitations due to coherent synchrotron radiation (CSR) and transverse jitter. The former limitation arises because double EEX uses twice as many bending magnets as single EEX which means stronger CSR effects degrading the beam quality. The latter limitation arises because a longitudinal jitter in front of the first EEX beamline is converted into a transverse jitter in the middle section (between the EEX beamlines) which can cause beam loss or beam degradation. In this paper, we numerically explore the effects of these two limitations on the emittance and beam transport.

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THPAB062

Preliminary Simulations on Chirpless Bunch Compression using Double-EEX Beamline

quadrupole, controls, simulation, dipole

3862

G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
M.E. Conde, D.S. Doran, W. Gai, J.G. Power
ANL, Argonne, Illinois, USA

Funding: This work is supported by Department of Energy, Office of High Energy Physics, under Contract No. DE-AC02-06CH11357.
An emittance exchange (EEX) beamline can be used to compress an electron bunch via its transverse-to-longitudinal exchange mechanism. We are investigating this as an alternative to the normal magnetic chicane bunch compressor. The chicane method requires a longitudinal chirp before the chicane (since it relies on the path length difference of different energies) which results in an unwanted chirp after the compressor. Alternatively, the EEX method uses quadrupole magnets to compress the bunch. In this paper, we present preliminary simulations in preparation for a demonstration of chirp-less bunch compression using an EEX beamline at the Argonne Wakefield Accelerator facility.

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THPAB065

A Tool for Small Longitudinal Beam Dynamics in Synchrotrons

impedance, synchrotron, simulation, longitudinal-dynamics

3865

J.-F. Ostiguy, V.A. Lebedev
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
A number of codes are available to simulate longitudinal dynamics in synchrotrons. The most established ones include TIBETAN, LONG1D, ORBIT, and ESME. While they embody a wealth of accumulated wisdom and experience, most of these codes were written decades ago and to some extent they reflect the constraints of their time. As a result, there is interest for updated tools taking better advantage of modern software and hardware capabilities. At Fermilab, the PIP-II project has provided the impetus for development of such a tool. In this contribution, we discuss design decisions and code architecture. A selection of test cases based on an initial prototype are presented.

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THPAB066

Modeling Cathode Roughness, Work Function, and Field Enhancement Effects on Electron Emission

electron, simulation, scattering, photon

3869

D.A. Dimitrov, G.I. Bell, D.N. Smithe, S.A. Veitzer
Tech-X, Boulder, Colorado, USA
I. Ben-Zvi, J. Smedley
BNL, Upton, Long Island, New York, USA
J. Feng, S.S. Karkare, H.A. Padmore
LBNL, Berkeley, California, USA

Funding: This work is supported by the US DOE Office of Science, department of Basic Energy Sciences under grant DE-SC0013190.
Recent developments in material design and growth have resulted in photocathodes that can deliver high quantum efficiency and are sufficiently robust to use in high electric field gradient photoinjectors and free electron lasers. The growth process usually produces photoemissive material layers with rough surface profiles that lead to transverse accelerating fields and possible work function variation resulting in emittance growth. To better understand the effects of surface roughness on emitted electron beams, we have developed realistic three-dimensional models for photocathode materials with grated surface structures. They include general modeling of electron excitation due to photon absorption, charge transport and emission from rough surfaces taking into account image charge and field enhancement effects. We implemented these models in the VSim particle-in-cell code. We report results from simulations using different photocathode materials with grated and flat surfaces to investigate how controlled roughness, work function variation, and field enhancement affect emission properties.

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THPAB072

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

electron, linac, 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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THPAB073

Magnetized and Flat Beam Experiment at FAST

electron, quadrupole, radiation, cathode

3876

A. Halavanau, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
J. Hyun
Sokendai, Ibaraki, Japan
D. Mihalcea, P. Piot, T. Sen, J.C.T. Thangaraj
Fermilab, Batavia, Illinois, USA

A photocathode, immersed in solenoidal magnetic field, can produce canonical-angular-momentum (CAM) dominated electron beams. Such beams have an application in electron cooling of hadron beams and can also be uncoupled to yield asymmetric-emittance (flat) beams. In the present paper we explore the possibilities of the flat beam generation at Fermilab's Accelerator Science and Technology (FAST) facility linear accelerator. We present optimization of the beam flatness and four-dimensional transverse emittance and investigate the mapping and its limitations of the produced eigen-emittances to conventional emittances using a skew-quadrupole channel. Possible application of flat beams at the FAST facility are also discussed.

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THPAB079

Terahertz Chirper for the Bunch Compression of Ultra-Low Emittance Beams

electron, coupling, dipole, laser

3899

A.R. Vrielink, A. Marinelli, E.A. Nanni
SLAC, Menlo Park, California, USA

Recent efforts have demonstrated the possibility of achieving ultralow transverse emittance beams for high brightness light sources and free electron lasers*. While these lower emittances should translate to improved lasing efficiency and higher peak brightness in FELs, these beams are commensurately more vulnerable to coherent synchrotron radiation (CSR) for the selfsame reasons. Conserving these ultralow emittances through the bunch compressors in an FEL given their increased propensity to emit CSR is particularly challenging. We investigate the possibility of imposing a large energy chirp at terahertz wavelengths to reduce the required magnetic fields in the compressor, counteracting the ultralow emittance in the generation of CSR. A second, higher frequency THz chirper would then be used to dechirp the beam after the chicane. Operation at THz as opposed to conventional radiofrequencies offers significantly larger chirp at similar input powers, yet still with wavelengths greater than typical FEL bunch lengths (several femtoseconds). Potential experimental schemes will be suggested in the context of LCLS and their feasibility evaluated.
* S. Bettoni, M. Pedrozzi and S. Reiche, Phys. Rev. ST Accel. Beams. 18, 123403 (December, 2015).

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THPAB081

The Effects of Space-Charge on the Dynamics of the Ion Booster in the Jefferson Lab EIC (JLEIC)

booster, space-charge, resonance, injection

3906

E.W. Nissen, S.A. Bogacz
JLab, Newport News, Virginia, USA

Funding: Notice: This manuscript has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy.
Optimization of the booster synchrotron design to operate in the extreme space-charge dominated regime is proposed. This study is motivated by the ultra-high luminosity promised by the JLEIC accelerator complex, which poses several beam dynamics and lattice design challenges for its individual components. We examine the effects of space charge on the dynamics of the booster synchrotron for the proposed JLEIC electron ion collider. This booster will inject and accumulate protons and heavy ions at an energy of 280 MeV and then engage in a process of acceleration and electron cooling to bring it to its extraction energy of 8 GeV. This would then be sent into the ion collider ring part of JLEIC. In order to examine the effects of space charge on the dynamics of this process we use the software SYNERGIA.

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THPAB082

The Beam-Beam Effect and Its Consequences for the Modeling of the Jefferson Lab EIC

electron, proton, beam-beam-effects, collider

3909

E.W. Nissen
JLab, Newport News, Virginia, USA

Funding: Notice: This manuscript has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy
In this work we address the effect of beam jitter on emittance growth as caused by the beam-beam effect on the Jefferson Lab Electron Ion Collider (JLEIC). This proposed collider would collide up to 100 GeV proton beams with up to 10 GeV electron beams. Due to the asymmetric rigidities of the beams and their non-linear lensing action on each other during a collision, collective effects can limit beam storage times. Using simulations we determined that one of JLEIC's synchronization concepts would require a new set of software tools to accurately understand phase space evolution.

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THPAB085

Simulations of Coherent Synchrotron Radiation on Parallel Hybrid GPU/CPU Platform

simulation, GPU, radiation, synchrotron

3915

B. Terzić, D. Duffin, A.L. Godunov
ODU, Norfolk, Virginia, USA
A. Arumugam, T. Islam, D. Ranjan, S. Sangam, M. Zubair
ODU CS, Norfolk, Virginia, USA

Funding: National Science Foundation 1535641
Coherent synchrotron radiation (CSR) is an effect of self-interaction of an electron bunch as it traverses a curved path. It can cause a significant emittance degradation, as well as fragmentation and microbunching. Numerical simulations of the 2D/3D CSR effects have been extremely challenging due to computational bottlenecks associated with calculating retarded potentials via integrating over the history of the bunch. We present a new high-performance 2D, particle-in-cell code which uses massively parallel multicore GPU/GPU platforms to alleviate computational bottlenecks. The code formulates the CSR problem from first principles by using the retarded scalar and vector potentials to compute the self-interaction fields. The speedup due to the parallel implementation on GPU/CPU platforms exceeds three oders of magnitude, thereby bringing a previously intractable problem within reach. The accuracy of the code is verified against analytic 1D solutions (rigid bunch) and semi-analytic 2D solutions for the chirped bunch. Finally, we use the new code in conjunction with a genetic algorithm to optimize the design of a fiducial chicane.

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THPAB087

Emittance Measurements and Simulations in 112 MHz Super-Conducting RF Electron Gun With CsK2Sb Photo-Cathode

gun, solenoid, electron, SRF

3921

K. Mihara
Stony Brook University, Stony Brook, USA
D. Kayran, V. Litvinenko, T.A. Miller, I. Pinayev
BNL, Upton, Long Island, New York, USA

The commissioning of the coherent electron cooling (CeC) proof of principle experiment is under way at Relativistic Heavy Ion Collider (RHIC).. A 112 MHz superconducting radio frequency photo-emission gun is used to generate the electron beam for this experiment. In this paper we report selected results of experimental emittance measurements and compare them with our simulations.

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THPAB088

Comparison of Theory, Simulation, and Experiment for Dynamical Extinction of Relativistic Electron Beams Diffracted Through a Si Crystal Membrane

electron, simulation, scattering, experiment

3924

L.E. Malin, W.S. Graves, J. Spence, C. Zhang
Arizona State University, Tempe, USA
R.K. Li, C. Limborg, E.A. Nanni, X. Shen, S.P. Weathersby
SLAC, Menlo Park, California, USA

Diffraction in the transmission geometry through a single-crystal silicon slab is exploited to control the intensity of a relativistic electron beam. The choice of crystal thickness and incidence angle can extinguish or maximize the transmitted beam intensity via coherent multiple Bragg scattering; thus, the crystal acts as a dynamical beam stop through the Pendel'sung effect, a well-known phenomenon in X-ray and electron diffraction. In an initial experiment, we have measured the ability of this method to transmit or extinguish the primary beam and diffract into a single Bragg peak. Using lithographic etching of patterns in the crystal we intend to use this method to nanopattern an electron beam for production of coherent x-rays. We compare the experimental results with simulations using the multislice method to model the diffraction pattern from a perfect silicon crystal of uniform thickness, considering multiple scattering, crystallographic orientation, temperature effects, and partial coherence from the momentum spread of the beam. The simulations are compared to data collected at the ASTA UED facility at SLAC for a 340 nm thick Si(100) wafer with a beam energy of 2.35 MeV.

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THPAB143

Operational Experience With the New Digital Low-Level RF System for CERN's PS Booster

LLRF, extraction, HLRF, booster

4058

M.E. Angoletta, S.C.P. Albright, A. Findlay, S. Hancock, M. Jaussi, J.C. Molendijk, J. Sanchez-Quesada
CERN, Geneva, Switzerland

The four rings of CERN's PS Booster have been equipped in 2014 with a new digital low-level RF (LLRF) system based upon a new, in-house developed LLRF family. This is a second-generation LLRF family that has been since then deployed on other synchrotrons. The paper provides an overview of the system's commissioning and first years of operation. In particular, an overview is given of the main system features and capabilities, such as beam loops and longitudinal beam blowup implementation. Operational improvements with respect to the previous, analogue digital LLRF are also mentioned, together with the planned system evolution to satisfy new requirements.

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THPAB155

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

gun, linac, 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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THPIK008

Beam Dynamics for the ThomX Linac

electron, gun, solenoid, focusing

4121

L. Garolfi, C. Bruni, M. El Khaldi, C. Vallerand
LAL, Orsay, France

We report the results of a recent beam dynamics study that has led to promising working points for the split ThomX photoinjector. ThomX is a back-scattering Thomson light source that will use S-band electron Linac with an energy of 50 MeV to produce 45 keV high X-rays flux (10¹¹ - 10¹³ ph/s), by means of collision between electron bunches and laser pulses, in the energy range from 45 keV to 90 keV. Since Thomx has been conceived to maximise the average X-rays flux in a fixed bandwidth, the high rate electron-photon collisions impose a linear accelerator combined with a storage ring. The high performances of the accelerator are largely affected by the high quality of the electron beam at the interaction point in the ring. Beam specifications should be achieved at the interaction point to the extent that 1 nC, 50 nA average current per bunch with normalised rms transverse emittance less than 5 mm and around 0.3% energy spread, at the end of the linac. The beam dynamics along the linac has been studied to demonstrate the capability of the accelerator to meet the requirements for the high brightness electron beam using an RF photoinjector configuration.

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THPIK037

Simulation Study of Normal-Conducting Double RF System for the 3-GeV KEK Light Source Project

cavity, beam-loading, storage-ring, simulation

4176

N. Yamamoto, S. Sakanaka, T. Takahashi
KEK, Ibaraki, Japan

For the proposed 3-GeV KEK Light Source (KEK-LS) project*, a double RF system using 500-MHz accelerating and 1.5-GHz third-harmonic cavities is under consideration. To mitigate intrabeam scattering due to ultra-low emittance, the bunch length will be elongated using the harmonic cavities which is based on the TM020 resonant mode. An accelerating cavity based on this mode was first proposed by Ego et al.**, and we found it very suitable for the harmonic cavities due to the following reasons: 1) it has high unloaded-Q and high stored electromagnetic energy which result in the reduction of transient beam-loading effect due to bunch gaps, and 2) efficient damping of higher (or lower) order modes is possible. Our investigations based on numerical simulations predicted the bunch elongation by a factor of 3.1 when realistic bunch-gaps were assumed. To improve the bunch elongation further, we also proposed to compensate the transient beam loading with two realistic measures: 1) compensation of rf voltages due to feedforward technique, and 2) compensation using a separate rf cavity. We will present our study on the double rf system based on numerical simulations.
* K. Harada et al., IPAC2016, THPMB012.
** H. Ego et al., Proceedings of the 11-th Annual Meeting of Particle Accelerator Society of Japan, Aug. 9-11, 2014, MOOL14 [in Japanese].

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THPIK064

Beam Lifetime Analysis of HLS-II Storage Ring

storage-ring, scattering, vacuum, operation

4242

K. Xuan, C. Li, J.Y. Li, G. Liu, G. Liu, J.G. Wang, L. Wang, W. Xu
USTC/NSRL, Hefei, Anhui, People's Republic of China

Beam lifetime is one of the important parameters of electron storage rings, which can describe the particle loss rate quantitatively and is restrict by quantum lifetime, beam-gas scattering and Touschek effect. The upgrade project of Hefei light source, named HLSII, has greatly improved the performance of the light source. The beam lifetime has been maintained at more than 5 hours. In this paper, a combined analysis method is derived by the analysis of the beam lifetime, and the method is applied to the HLSII storage ring. The experimental results show that this method is simple and reliable for the analysis of the Touschek lifetime and beam-gas scattering lifetime.

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THPIK073

Development of RFQ for BNCT Accelerator

rfq, cavity, operation, proton

4260

J. Bahng
Kyungpook National University, Daegu, Republic of Korea
B.H. Choi
IBS, Daejeon, Republic of Korea
B.H. Choi, D.S. Kim
DAWONSYS, Ansan-si, Republic of Korea
E.-S. Kim
Korea University Sejong Campus, Sejong, Republic of Korea

A accelerator for Boron Neutron Capture Therapy (BNCT) based on proton linac has been developed as a domestic project. The accelerator system consists of duo plasmatron as an ion source, low energy beam transport (LEBT), radio frequency quarupole (RFQ) accelerator, drift tube linac (DTL). In order to achieve beam power of 50 kW, the required beam intensity and energy are 50 mA and 10 MeV, respectively. Since high duty rate provides high efficient medical treatment, the design of the cw RFQ has been investigated to accelerate proton beam from 50 keV to 3 MeV with beam intensity of 60 mA. In this paper, beam dynamics and design of the RFQ are presented in detail.

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THPIK093

Blow-Up Due to Intra Beam Scattering during Deceleration in ELENA

simulation, scattering, electron, antiproton

4303

C. Carli, M. Martini
CERN, Geneva, Switzerland

Intra Beam Scattering (IBS) is expected to be the main performance limitation of the Extra Low Energy Antiproton ring (ELENA), a small synchrotron equipped with electron cooling under construction at CERN to decelerate antiprotons from 5.3 MeV to 100 keV. Thus, the duration of the ramps must not be too long to avoid excessive blow up due to IBS. On the other hand, the bending magnets are C-shaped and the vacuum chambers are without insulated junctions, which are difficult for fully baked machines; thus, the ramps must not be too short. The evolution of transverse and longitudinal emittances along the ramps have been estimated assuming that IBS is the main phenomenon leading to blow-up. The blow-up due to IBS found along the ramps have been found to be acceptable.

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THPVA002

Numerical Investigation of Beam Halo From Beam Gas Scattering in KEK-ATF

simulation, scattering, vacuum, damping

4410

R.J. Yang, P. Bambade
LAL, Orsay, France
K. Kubo, T. Okugi, N. Terunuma, D. Zhou
KEK, Ibaraki, Japan

To demonstrate the final focus schemes of the Future Linear Collider (FLC), the Accelerator Test Facility 2 (ATF2) at KEK is devoted to focus the beam to a RMS size of a few tens of nanometers (nm) vertically and to provide stability at the nm level at the virtual Interaction Point (IP). However, the loss of halo particles upstream will introduce background to the diagnostic instrument measuring the ultra-small beam, using a laser interferometer monitor. To help the realization of the above goals and beam operation, understanding and mitigation of beam halo are crucial. In this paper, we present the systematical simulation of beam halo formation from beam gas Coulomb scattering (BGS) in the ATF damping ring. The behavior of beam halo with various machine parameters is also discussed.

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THPVA003

Status of the Beam Dynamics Design of the New Post-Stripper DTL for GSI-FAIR

DTL, quadrupole, simulation, ion

4414

A. Rubin, X. Du, L. Groening, M. Kaiser, S. Mickat
GSI, Darmstadt, Germany

The GSI UNILAC has served as injector for all ion species since 40 years. Its 10⁸ MHz Alvarez DTL providing acceleration from 1.4 MeV/u to 11.4 MeV/u has suffered from material fatigue and has to be replaced by a new section. The design of the new post-stripper DTL is now under development in GSI. Five Alvarez tanks with four intertank sections provide 100% transmission and low emittance growth. The intertank sections allow for a matched solution and provide place for diagnostics. Simulations along the complete Alvarez DTL were done for 238U²⁸⁺ using the TraceWin code. The transversal zero current phase advance is 65' for all tanks. Results of beam dynamics simulations for six different scenarios as well as an error study for the FAIR nominal case are presented.

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THPVA007

Matching Space-charge Dominated Electron Bunches into the Plasma Accelerator at SINBAD

electron, plasma, simulation, focusing

4429

J. Zhu, R.W. Aßmann, U. Dorda, B. Marchetti
DESY, Hamburg, Germany

The SINBAD facility (Short and INnovative Bunches and Accelerators at DESY) is foreseen to provide sub-fs to tens of fs electron bunches for Laser Wake-Field Acceleration (LWFA) experiments. In order to avoid emittance growth in plasma cells with ultra-high accelerating gradients the injection and transport of electron bunches with beta functions of mm-size or even smaller are required. This kind of bunch is usually space-charged dominated since the energy is low (< 200 MeV) while the peak current is high for allowing the electron bunches to be used for Free Electron-Laser (FEL) generation. We present the beamline design and explore the possible beam parameters at the SINBAD linac by start-to-end simulations.

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THPVA009

Transverse Beam Dynamics of an 8 MeV Electron Linac

solenoid, focusing, linac, 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, linac

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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THPVA013

Benchmarking of the ESS LEBT in TraceWin and IBSimu

proton, ion, simulation, rfq

4445

Ø. Midttun
University of Bergen, Bergen, Norway
Y.I. Levinsen, R. Miyamoto, D.C. Plostinar
ESS, Lund, Sweden

The modeling of the proton beam in the ESS accelerator starts with a beam distribution as an input to the TraceWin code currently used as the simulation tool. This input is typically a Gaussian distribution, a distribution from other codes, or data from an emittance measurement. The starting point of these simulations is therefore located somewhere along the low energy beam transport (LEBT) close to the ion source. In this paper, we propose to use IBSimu to model the beam extraction from the ion source, which provides an input beam distribution to TraceWin. IBSimu is a computer simulation package for ion optics, plasma extraction, and space charge dominated ion beam transport. We also present a benchmarking of the beam tracking through the LEBT using both these tools, and propose a transition interface to handover the beam distribution from IBSimu to TraceWin.

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THPVA015

Application of Modified KV-Distributions to Study the Phase Portrait Transformation of Intense Bunches in Magnetic Fields

cyclotron, optics, electronics, multipole

4448

H.Y. Barminova
MEPhI, Moscow, Russia

Modified KV-distribution functions are applied to study the intense bunch behavior in transverse magnetic fields. The functions used allow to consider both the emittance-dominated and charge-dominated bunches in 2D and 3D approximations. Peculiarities of the bunch phase portrait transformation in magnetic fields of achromatic structures are discussed. Particular case is proved to exist characterized by the absence of the emittance transfer.

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THPVA019

Self-consistent Space Charge Tracking Method based on Lie Transform

space-charge, simulation, proton, sextupole

4454

E. Laface, J. F. Esteban Müller
ESS, Lund, Sweden

In this paper we propose to describe the self-force of a particles beam, known as space charge, as an Hamiltonan term dependent on the distribution of the particles' coordinates: H_sc = H_sc(ρ(x,y,z)). This Hamiltonian is then used, together with the kinetic component H_k in a Lie transform to generate a transport map by e^{-L:H_k +H_sc}: where the Lie operator :H_k + H_sc: is defined according to the Dragt's notation [1]. Then the Lie transform is used to transport directly the distribution function ρ(x, y, z) in a self-consistent iterative algorithm. The result of this proof-of-concept idea is verified on a drift space and on a FODO channel and compared with a traditional multi-particles simulation code.

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THPVA023

Studies of Longitudinal Beam Stability in CERN PS Booster After Upgrade

impedance, simulation, space-charge, injection

4469

D. Quartullo, S.C.P. Albright, E.N. Shaposhnikova
CERN, Geneva, Switzerland

The CERN PS Booster, comprised of four superposed rings, is the first synchrotron in the LHC proton injection chain. In 2021, after major upgrades, the injection and extraction beam energies, as well as the acceleration rate, will be increased. The required beam intensities should be a factor of two higher for nominal LHC and fixed-target beams, and the currently used narrow-band ferrite systems will be replaced by broad-band Finemet cavities in all four rings. Future beam stability was investigated using simulations with the Beam Longitudinal Dynamics (BLonD) code. The simulation results for existing situation were compared with beam measurements and gave a good agreement. An accurate impedance model, together with a careful estimation of the longitudinal space charge, was used in simulations of the future acceleration cycle in single and double RF, with phase and radial loops and controlled longitudinal emittance blow-up. Since the beam is not ultra-relativistic and fills the whole ring (h=1), the front and multi-turn back wakes were taken into account, as well as the RF feedbacks which reduce the effect of the Finemet impedance at the revolution frequency harmonics.

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THPVA024

Controlled Longitudinal Emittance Blow-Up Using Band-Limited Phase Noise in CERN PSB

simulation, impedance, synchrotron, injection

4473

D. Quartullo, E.N. Shaposhnikova, H. Timko
CERN, Geneva, Switzerland

Controlled longitudinal emittance blow-up (from 1 eVs to 1.4 eVs) for LHC beams in the CERN PS Booster is currently achievied using sinusoidal phase modulation of a dedicated high-harmonic RF system. In 2021, after the LHC injectors upgrade, 3 eVs should be extracted to the PS. Even if the current method may satisfy the new requirements, it relies on low-power level RF improvements. In this paper another method of blow-up was considered, that is the injection of band-limited phase noise in the main RF system (h=1), never tried in PSB but already used in CERN SPS and LHC, under different conditions (longer cycles). This technique, which lowers the peak line density and therefore the impact of intensity effects in the PSB and the PS, can also be complementary to the present method. The longitudinal space charge, dominant in the PSB, causes significant synchrotron frequency shifts with intensity, and its effect should be taken into account. Another complication arises from the interaction of the phase loop with the injected noise, since both act on the RF phase. All these elements were studied in simulations of the PSB cycle with the BLonD code, and the required blow-up was achieved.

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THPVA031

Beam Tests of Diamond-Like Carbon Coating for Mitigation of Electron Cloud

electron, proton, operation, extraction

4497

J.S. Eldred, M. Backfish, C.-Y. Tan, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
S. Kato
KEK, Ibaraki, Japan

Electron cloud beam instabilities are an important consideration in virtually all high-energy particle accelerators and could pose a formidable challenge to forthcoming high-intensity accelerator upgrades. Our results evaluate the efficacy of a diamond-like carbon (DLC) coating for the mitigation of electron in the Fermilab Main Injector. The interior surface of the beampipe conditions in response to electron bombardment from the electron cloud and we track the change in electron cloud flux over time in the DLC coated beampipe and uncoated stainless steel beampipe. The electron flux is measured by retarding field analyzers placed in a field-free region of the Main Injector. We find the DLC coating reduces the electron cloud signal to roughly 2\% of that measured in the uncoated stainless steel beampipe.

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THPVA047

Developing an Yb/Nd Doped Hybrid Solid Laser of RF Gun for SuperKEKB Phase II Commissioning

laser, gun, cavity, electron

4540

X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida, R. Zhang
KEK, Ibaraki, Japan

The electron beams with a charge of several nC and a normalized emittance of less than 10 'm are expected to be generated in the photocathode RF gun for injector linac of SuperKEKB accelerator project. By development of the Yb-doped laser system, more than 1.0 nC electron has been obtained in 25 Hz. The laser system is already for commissioning phase I. But, the 30 ps pulse width stretch limit the pulse energy of the amplifier laser system. As well-established laser material, Nd:YAG rods with high optical homogeneity and high damage threshold, simplify the design of high-pulse-energy amplifier. Therefore, a new Nd/Yb hybrid laser system is development to increase the pulse energy of the laser source. For phase II commissioning, more than 3 nC electron beam is expected. Also, a chirped pulse amplification (CPA) laser system is prepared for the phase III commissioning, both pulse energy and pulse shaping controller are expected.

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THPVA048

Design and Progress on Mechanical & Alignment System for HEPS-TF

alignment, controls, sextupole, quadrupole

4544

C. H. Li, S.J. Li, J. Liu, H. Wang, X.L. Wang, Z. Wang, L. Wu
IHEP, Beijing, People's Republic of China

HEPS is a new generation synchrotron facility with a stringent requirement of very low emmittance. The key technology difficulties are supposed be overcome during the HEPS-TF stage. There are two projects in progress for mechanical and alignment system. One is the development of precision auto-tuning magnet girder, to meet the requirement of beam based alignment in tunnel, the other is the study on vibrating-wire alignment technique to improve alignment accuracy of magnets on a girder. This paper will describe the design and progress of both projects.

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THPVA051

Vibration Study of Magnet Girder of the HEPS-TF

photon, experiment, factory, quadrupole

4554

Z. Wang, C. H. Li, H. Qu, H. Wang
IHEP, Beijing, People's Republic of China

Abstract: There are stringent requirements on beam stability in the High Energy Photon Source (HEPS). The stability of the magnet girder is an extremely important factor for the beam stability. This paper will discuss the influence of ground vibration to the beam stability. This influence will determine the scope of the vibration magnification of the magnet girder. By improving the stiffness of the magnet girder, the influence will be reduced and the beam stability shall be improved. Besides, the progress of the HEPS-TF girder prototype and the vibration test will be described.

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THPVA072

Travelling Laser Focus System for the Particles Acceleration

laser, acceleration, radiation, photon

4613

A.A. Mikhailichenko
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

We describe the result of the wake-fields calculation in a device for acceleration of particles in the micro-structures illuminated by the swept laser bust. Calculations carried with help of FlexPDE code.

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THPVA075

Beam Measurements in the MedAustron Synchrotron With Slow Extraction and Off-Momentum Operation

synchrotron, extraction, betatron, pick-up

4623

C. Kurfürst, A. De Franco, F. Farinon, M. Kronberger, S. Myalski, S. Nowak, F. Osmić, M.T.F. Pivi, C. Schmitzer, P. Urschütz, A. Wastl
EBG MedAustron, Wr. Neustadt, Austria
A. Garonna
TERA, Novara, Italy
T.K.D. Kulenkampff
CERN, Geneva, Switzerland
L.C. Penescu
Abstract Landscapes, Montpellier, France

The MedAustron Ion Therapy Center is a medical accelerator facility for hadron therapy cancer treatment using protons and carbon ions. The facility features 4 irradiation rooms, three of which are dedicated to clinical operation and a fourth one dedicated to non-clinical research. The latter was handed over to researchers in autumn 2016. A 7 MeV/n injector feeds a 77 m circumference synchrotron which provides beams for treatment and research. Routine verification measurements in the synchrotron involve beam emittance, dispersion as well as tunes and chromaticity. The horizontal and vertical emittance are measured using scraping plates and a direct current transformer. The dispersion function in the ring is determined by sweeping the synchrotron RF frequency while measuring the beam position in the shoe-box pick-ups. The horizontal and vertical betatron tune and chromaticity are measured with Direct Diode Detection electronics, developed at CERN, while changing the beam position with the RF radial loop. The beam is kept off-momentum, thus in dispersive regions the closed orbit is largely offset from the central orbit. Methods for beam measurements in the synchrotron are presented.

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THPVA084

Evaluation of Collective Effects in Iranian Light Source Facility (ILSF) Storage Ring

impedance, storage-ring, vacuum, scattering

4650

E. Ahmadi, S. Ahmadiannamin, J. Rahighi
ILSF, Tehran, Iran
S.M. Jazayeri
IUST, Narmac, Tehran, Iran

In this paper, we present the calculations of various collective effects in the storage ring of ILSF, a synchrotron light source under design in Iran. The ILSF storage ring is based on 5-BA lattice structure and emittance of 270 pm-rad which is optimized to provide high brightness and flux photons for the users. Because of design features, small radius vacuum pipe and small momentum compaction factor of lattice, it is expected that instabilities emerging from collective effects will affect significantly the beam quality and make it is challenging to reach maximum designed beam current. We will address the results of beam quality degradation and threshold calculations for different singlebunch and multibunch instabilities.

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THPVA086

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

electron, simulation, space-charge, linac

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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