IPAC2017 - List of Keywords (operation)

Paper	Title	Other Keywords	Page
MOXAA1	Commissioning of the European XFEL Accelerator	linac, electron, undulator, emittance	1
	W. Decking, H. Weise DESY, Hamburg, Germany
	The European XFEL uses the world's largest superconducting RF installation to drive three independent SASE FELs. After eight years of construction the facility is now brought into operation. First experience with the superconducting accelerator as well as beam commissioning results will be presented. The path to the first user experiments will be laid down.
	Slides MOXAA1 [22.967 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOXAA1
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MOYAA1	Approaching the Nominal Performance at the LHC	luminosity, emittance, 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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOYAA1
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MOZA1	Electron Cloud Effects at the LHC and LHC Injectors	electron, simulation, emittance, 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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MOOCA3	Amorphous Carbon Thin Film Coating of the SPS Beamline: Evaluation of the First Coating Implementation	vacuum, electron, cathode, proton	44
	M. Van Gompel, P. Chiggiato, P. Costa Pinto, P. Cruikshank, C. Pasquino, J. Perez Espinos, A. Sapountzis, M. Taborelli, W. Vollenberg CERN, Geneva, Switzerland
	As part of the LHC Injector Upgrade (LIU) project, the Super Proton Synchrotron (SPS) must be upgraded in order to inject in the LHC 25 ns bunch spaced beams of higher intensity. To mitigate the Electron Multipacting (EM) phenomenon in the SPS, CERN developed thin film carbon coatings with a low Secondary Electron Yield (SEY). The development went from coating small samples, up to coating of 6 m long vacuum chambers directly installed in the magnets. To deposit the low SEY amorphous carbon (aC) film on the vacuum chamber inner wall of SPS ring components, a modular hollow cathode train was designed. The minimization of the logistical impact requires a strategy combining in-situ and ex-situ coating, depending on the type of components. To validate the implementation strategy of the aC thin films and the in-situ coating process along the 7 km long SPS beamline, approximately 2 cells of B-type bending dipoles and 9 focussing quadrupoles are foreseen to be treated with the aC coating during the Extended Year End Technical Stop (EYETS) 2016-2017. We will discuss the coating technique and evaluate both the implementation process and the resulting coating performance.
	Slides MOOCA3 [71.421 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOOCA3
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MOOCB2	Laser System Design and Operation for SNS H⁻ Beam Laser Stripping	laser, experiment, ion, neutron	57
	Y. Liu, A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, A.A. Menshov, A. Webster ORNL, Oak Ridge, Tennessee, USA A. Rakhman ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: This work has been partially supported by U.S. DOE grant DE-FG02-13ER41967. ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. Recently, a high-efficiency laser assisted hydrogen ion (H⁻) beam stripping was successfully carried out in the Spallation Neutron Source (SNS) accelerator. The experiment was not only an important step toward foil-less H⁻ stripping for charge exchange injection, it also served as a first example of using megawatt ultraviolet (UV) laser in an operational high power proton accelerator facility. This talk reports the design, implementation, and commissioning results of the macropulse laser system, laser transport line, and laser operation for the laser stripping experiment. The macropulse laser consists of a mode-locked picosecond pulsed seed laser and a burst-mode Nd:YAG laser amplifier. The general design concept can be adapted to any temporal beam structures in most accelerators. We have achieved UV pulses with the pulse widths varying between 34 to 54 ps and a maximum peak power over 3.5 MW. A laser transport line is installed to deliver the UV beam to the laser stripping chamber at a transmission efficiency of 70%. Laser operation including remote control and monitor of laser parameters will be described.
	Slides MOOCB2 [11.306 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOOCB2
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MOPAB004	Improved Protection of the Warm Magnets of the LHC Betatron Cleaning Insertion	shielding, radiation, luminosity, collimation	72
	C. Bahamonde Castro, F. Cerutti, P. Fessia, A. Lechner, A. Mereghetti, D. Mirarchi, S. Redaelli, E. Skordis CERN, Geneva, Switzerland E. Skordis The University of Liverpool, Liverpool, United Kingdom
	After the High Luminosity (HL) upgrade in 2024-2026, the LHC is anticipated to increase its integrated luminosity by a factor of 10 beyond its original design value of 300 fb-1. In preparation for this, several improvements to the equipment will already be implemented during the next Long Shutdown (LS2) starting in 2019. In the betatron cleaning insertion, the debris leaking out of several collimators will deposit energy in the downstream warm magnets, causing long-term radiation damage. A new layout has been proposed in which the most exposed magnet of each assembly is removed, reducing the assembly from 6 to 5 magnet units and gaining 2 spare magnets. New absorbers are therefore required to enhance the shielding of the remaining magnet string. In this paper, we present an evaluation of the dose to the warm magnets for post-LS2 operation, and we quantify the achievable reduction of the long-term radiation damage for different absorber configurations. A solution for an improved magnet protection that fulfills the HL-LHC requirements is proposed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB004
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MOPAB032	Status of a Double Slit Interferometer for Transverse Beam Size Measurements at BESSY II	diagnostics, storage-ring, synchrotron, radiation	149
	M. Koopmans, P. Goslawski, J.G. Hwang, M. Ries, M. Ruprecht, A. Schälicke HZB, Berlin, Germany
	Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of Helmholtz Association The upgrade of the BESSY II storage ring to BESSY VSR* demands additional beam diagnostics for machine commissioning and development. Especially bunch resolved measurements are needed. Currently, transverse beam size measurements are done with X-ray pinhole monitor systems, which cannot provide bunch resolved information. Alternative methods to measure the transverse beam size using synchrotron radiation in the visible spectrum are interferometric techniques, which could also be upgraded to bunch resolved systems. For that purpose a double slit interferometer has been constructed. Commissioning of the system has started and experimental results are discussed and compared with the existing pinhole system. * A. Jankowiak et al., eds., ''BESSY VSR - Technical Design Study'', Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany, June 2015.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB032
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MOPAB039	Development of a Control System Based on Experimental Data for Space Charge Lenses	electron, plasma, ion, space-charge	166
	S. Klaproth, C. Beberweil, M. Droba, O. Meusel, H. Podlech, B.E.J. Scheible, K. Schulte, K.I. Thoma, C. Wagner IAP, Frankfurt am Main, Germany
	Space charge lenses use a confined electron cloud for the focusing of ion beams. The electron density gives the focusing strength whereas the density distribution influences the mapping quality of the space charge lens and is related to the confinement. The major role of the electron density with respect to the focusing quality has been pointed out many times in the past ,. With an automated measurement system the radial light density profile, plasma stability and mean value of the electron density have been measured in respect to the confining fields and the pressure. The results are summarized in 3D-maps. The theoretical model approximations for space charge lenses predicts high electron densities then measured. With the automated system the realistic 3D-maps can be considered instead of an approximation of a theoretical density including knowledge of the most stable electron cloud achievable within the parameter range of the lens. The experimental results of the automated measurement system will be presented here and a concept of a control system for this type of space charge lenses will be explained. O. Meusel, 'Focussing and transport of ion beams using space charge lenses', PhD thesis, 2006
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB039
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MOPAB040	Linear and Nonlinear Optics Measurements With Multiturn Data at PETRA III	optics, kicker, diagnostics, injection	170
	I.V. Agapov, M. Bieler, H. Ehrlichmann, J. Keil, J. Klute, G. Kube, G.K. Sahoo, F. Schmidt-Föhre, R. Wanzenberg DESY, Hamburg, Germany R. Tomás, A. Wegscheider CERN, Geneva, Switzerland
	At Petra III measuring multiturn beam response to pulsed and continuous excitations allows linear and nonlinear (e.g. frequency maps) optics parameter determination. We describe the measurement setup, approaches to optics parameter determination, and the measurement results for Petra III.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB040
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MOPAB042	Two-Dimensional Synchrotron Radiation Interferometry at PETRA III	synchrotron, radiation, emittance, synchrotron-radiation	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB042
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MOPAB043	Very First Experience with the Standard Diagnostics at the European XFEL	diagnostics, electron, cavity, electronics	180
	D. Lipka DESY, Hamburg, Germany
	The whole European XFEL becomes in operation this year. Dedicated standard diagnostics systems are installed and almost all types are tested at the injector before. Now the standard diagnostics are used to commission the facility. In this contribution the very first results and the operation experiences of the standard beam diagnostics of the entire European XFEL are reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB043
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MOPAB070	Beam Position Measurement During Multi-Turn Painting Injection at the J-PARC RCS	injection, linac, proton, synchrotron	277
	N. Hayashi, A. Miura, P.K. Saha, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	Multi-turn painting injection scheme is important for high intensity proton accelerators. At the J-PARC RCS, a transverse painting scheme was adapted by adding vertical painting magnets to the beam transport line before the injection point, with horizontal painting being performed by a set of dedicated pulse magnets in the ring. To establish a transverse painting condition, it is usual to base on the pulse magnet current pattern. However, it is more desirable to directly measure the beam orbit time variation for evaluation. A linac beam was chopped to match the ring RF bucket. We thought that it would be difficult to measure the position for each pulse; however, the average position could be extracted by introducing a particular device. For the beam injected into the ring, because the linac RF frequency component was diminished due to debunching quickly, one could determine its position in the beginning of the injection period. However, due to rebunching effect the position determination becomes difficult. This problem needs to be resolved.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB070
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MOPAB071	A Beam Position Monitor for the Diagnostic Line in MEBT2 of J-PARC Linac	diagnostics, linac, pick-up, impedance	281
	A. Miura, Y. Kawane, J. Tamura JAEA/J-PARC, Tokai-mura, Japan T. Miyao KEK, Ibaraki, Japan
	In the linac of the Japan Proton Accelerator Research Complex (J-PARC), the neutral hydrogen (H⁰) generation from the negative hydrogen ion (H⁻) beam is one of key issues to mitigate the beam loss. In order to diagnose the H⁰ particles, we installed the bump magnets to make a chicane orbit of the H⁻ beam. To evaluate the horizontal shifts of the beam orbit, a beam position monitor (BPM) is fabricated. The BPM measures the shift-positions with various driving currents of the bump magnets. We employed the WSM to measure the H⁻ beam profile. It also help us to compare the shift-positions measured by BPM. In this paper, the design and the performance of the BPM is described. In addition, we describe how to compare the shift position.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB071
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MOPAB084	Online Measurement of Electrode Gains for Stripline Beam Position Monitor in the HLS II Storage Ring	storage-ring, quadrupole, site, radiation	316
	F.F. Wu, L. Lin, X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, J.G. Wang, J.H. Wei, Y.L. Yang, T.Y. Zhou, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Supported by the National Key Research and Development Program of China(No. 2016YFA0402000) and the National Science Foundation of China (11575181, 11605202) Three axially symmetric stripline beam position monitors were installed in the HLS II storage ring and each stripline BPM was machined with button BPM together. Due to mechanical errors of stripline BPM, differences in electrode gains will lead to measurement error for beam position and mutual coupling between beam horizontal position and vertical position. So it is very important to calibrate electrode gains for axially symmetric BPM. A method was proposed to calibrate electrode gains of this kind of BPM. This method is suitable for all axially symmetric BPMs, whether stripline BPM or button BPM. The online calibrated gains were compared with offline calibrated gains and the results have shown that online and offline calibrated electrode gains were basically consistent.
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MOPAB096	Universal Digital Aggregator for in-Line Signal Processing	hardware, software, target, PLC	352
	M.P. Kopeć, L.J. Dudek, A. Kisiel, M.A. Knafel, A.I. Wawrzyniak, M. Zając Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland
	Universal digital aggregator is a device for general signal processing with around 100kHz bandwidth. It contains of 4 inputs and 4 open-drain outputs - all of which are fully programmable. When the number of controlling digital signals exceeds the number of input ports of a device there is a need to either multiplex those signals or process them before the target device. The aggregator can be powered from the target device so no additional cabling is needed, especially considering its low power consumption. This straightforward, complex and portable device can be easily applied where PLC solutions are difficult to implement.
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MOPAB100	The Development of Button Type BPM Electronics for RAON	electronics, pick-up, ion, FPGA	362
	S.W. Jang, E.-S. Kim, Y. Lee Korea University Sejong Campus, Sejong, Republic of Korea Y.S. Chung, G.D. Kim, H.J. Woo IBS, Daejeon, Republic of Korea J.W. Kwon Korea University, Seoul, Republic of Korea
	RAON is a heavy ion accelerator for the Rare Isotope Science Project in Korea. The main goals of RAON is to accelerate various stable ions from ECR ion source and rare isotopes ions from ISOL beam line. For the stable beam operation, the beam diagnostics equipment is very important. Recently, we developed a digital board electronics for the button type beam position monitor (BPM) to measure the position of ion beams. In this presentation, design of electronics, beam signal simulation results, and RF measurement test results with a developed button BPM will be described.
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MOPAB109	Operational Experience with Luminosity Scans for Beam Size Estimation in 2016 LHC Proton Physics Operation	emittance, luminosity, 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	emittance, luminosity, experiment, detector	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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MOPAB113	Usage of the Transverse Damper Observation Box for High Sampling Rate Transverse Position Data in the LHC	injection, diagnostics, impedance, pick-up	389
	L.R. Carver, X. Buffat, A.C. Butterworth, W. Höfle, G. Iadarola, G. Kotzian, K.S.B. Li, E. Métral, M. Ojeda Sandonís, M.E. Söderén, D. Valuch CERN, Geneva, Switzerland
	The transverse damper observation box (ADTObsBox) is a device that makes accessible the bunch-by-bunch turn-by-turn data recorded from the pickups of the LHC transverse damper. This device can provide online transient analysis of different beam dynamics effects (tunes and damping times at injection, for example), while also under development is an online coherent instability triggering system. This paper will provide an overview of the current setup and plans for future upgrades, as well as detailing how it deals with the large volume of data being generated. The results of some analysis that rely on the ADTObsBox will also be shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB113
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MOPAB117	Online Bunch by Bunch Transverse Instability Detection in LHC	pick-up, network, feedback, injection	397
	M.E. Söderén, G. Kotzian, M. Ojeda Sandonís, D. Valuch CERN, Geneva, Switzerland
	Reliable detection of developing transverse instabilities in the Large Hadron Collider is one of the main operational challenges of the LHC's high intensity proton run. A full machine snapshot provided from the moment of instability is a crucial input to develop and fine tune instability models. The transverse feedback system (ADT) is the only instrument in LHC, where a full rate bunch by bunch transverse position information is available. Together with a sub-micron resolution it makes it a perfect place to detect transverse beam motion. Very large amounts of data, at very high data rates (8 Gb/s) need to be processed on the fly to detect onset of transverse instability. A very powerful computer system (so called ADTObsBox) was developed and put into operation by the CERN RF group, which is capable of processing the full rate data streams from ADT and perform an on the fly instability detection. The output of this system is a timing event with a list of all bunches developing instability, which is then sent to the LHC-wide instability trigger network to freeze other observation instruments. The device also provides buffers with raw position data for offline analysis.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB117
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MOPAB122	Fast Bunch by Bunch Tune Measurements at the CERN PS	injection, betatron, proton, synchrotron	415
	P. Zisopoulos, M. Gąsior, M. Serluca, G. Sterbini CERN, Geneva, Switzerland
	The CERN Proton Synchrotron (PS) is a crucial component of the Large Hadron Collider (LHC) injector complex. The PS role is to provide beams of high brightness and with the required time structure. In this paper, we present the results of bunch-by-bunch tune measurements by using turn-by-turn transverse beam position monitors (BPMs). The data from different BPMs are combined together to allow fast and accurate tune measurements for each bunch. The obtained results are compared with the present PS tune-meter system and the specific advantages and limits of this technique are commented and exemplified.
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MOPAB124	A Fast Gain Calibration Algorithm for Beam Position Monitoring at Taiwan Photon Source	pick-up, storage-ring, electron, target	419
	J.Y. Chen, C.H. Chen, M.-S. Chiu, P.C. Chiu, P.J. Chou, S. Fann, K.H. Hu, C.S. Huang, C.-C. Kuo, T.Y. Lee, C.C. Liang, Y.-C. Liu, G.-H. Luo, H.-J. Tsai, F.H. Tseng NSRRC, Hsinchu, Taiwan
	A stable, reliable and well-calibrated beam position monitor (BPM) system is essential for the operation of accelerators. At newly constructed Taiwan Photon Source (TPS), it not only helps us to determine the accelerator parameters, such as Twiss parameters and tune, but also to avoid the damage on accelerator instruments caused by high-energy particle beams or radiation. In this study, we demonstrate a new BPM calibration scheme at TPS storage ring. To excite the electron beams inside accelerator beam pipe by one horizontal or vertical corrector magnet, we measure the response of analog-to-digital converter (ADC) of each BPM pick-up electrodes with different lateral positions and beam currents. Depending on the measured ADC responses, we calibrated the beam position monitor system. Simultaneously, because of limited preparation time after every long shutdown, we are looking for a fast algorithm to ensure the measurement could be done easily and finished as quickly as possible.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB124
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MOPAB125	Post-Mortem System for the Taiwan Photon Source	kicker, timing, photon, data-acquisition	422
	C.Y. Liao, Y.-S. Cheng, K.T. Hsu, K.H. Hu, C.H. Huang, C.Y. Wu NSRRC, Hsinchu, Taiwan
	The Taiwan Photon Source (TPS), a 3-GeV third-generation synchrotron light source located in Hsinchu, is available to users since 2016. During operation, it will inevitably encounter system trips caused by beam losses. Thus, a post-mortem (PM) system is an important tool to analyze the cause of such events. Main functions of the PM system are: (i) PM trigger will be generated when the stored beam is suddenly lost abnormally; (ii) storage of relevant signals when the server receives such a trigger; (iii) PM Viewer to analyze each event and understand the cause and effect of a beam trip event. The post-mortem system architecture, plans and implementation will be discussed in this report.
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MOPAB131	Transverse Emittance Measurements Using LHCb's Beam-Gas Interactions	detector, emittance, real-time, experiment	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB131
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MOPAB151	Techniques for Transparent Lattice Measurement and Correction	lattice, feedback, betatron, storage-ring	483
	W.X. Cheng, K. Ha, Y. Li BNL, Upton, Long Island, New York, USA
	Funding: Work supported by DOE contract No: DE-SC0012704 NSLS-II storage ring started top off operation since Oct 2015. It has been noticed during the user operation that machine lattice was affected by insertion devices (ID). The storage ring coupling, emittance and lifetime vary when ID gap changes. Lattice characterization was typically carried out with dedicated machine study time with low storage current. Due to collective effect, the lattice at high operation current is different. To characterize the machine lattice during normal user operation with little disturbance, a small portion of beam (~1%) filled in the ion gap can be excited by the bunch by bunch feedback system near betatron frequency. Recent development on BPM electronics enables the gate function to detect partial beam motion in the ring. With the gated BPM turn by turn data from excited bunches, storage ring lattice can be measured and corrected with the well-developed tools. We present in the paper preliminary test results with these tools to characterize the lattice and how it improves the machine performance during user operation.
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MOPIK004	Demonstration of an All-Optically Driven Sub-keV THz Gun	electron, gun, acceleration, laser	503
	W.R. Huang, K.-H. Hong, F.X. Kärtner, E.A. Nanni, KR. Ravi MIT, Cambridge, Massachusetts, USA A-L. Calendron, H. Cankaya, A. Fallahi, F.X. Kärtner, X. Wu CFEL, Hamburg, Germany D. Zhang DESY, Hamburg, Germany
	Funding: European Research Council under the European Union Seventh Framework Program (FP/2007-2013)/ERC Grant Agreement no. 609920 Intense ultrashort THz and optical pulses with single-cycle pulse duration became possible after the recent advances in ultrafast technologies. Using such ultrashort pulses for electron acceleration offers advantages in terms of higher thresholds for material breakdown which opens up a promising path towards increased acceleration gradients. In addition, using optically generated THz pulses enable inherently synchronized acceleration schemes, since accelerating field and particle injecting field are excited by a single seed laser. In this contribution, we present the first experimental demonstration of laser-driven THz acceleration of electrons initially at rest. It is shown that strong-field, single-cycle THz fields accelerate electrons with peak energies of up to 0.8 keV in an ultracompact THz gun with bunch charge of 40 fC. The achieved energy spreads are as low as 5.8%.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK004
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MOPIK026	Commissioning and Operation of an Ultrafast Electron Diffraction Facility as Part of the ATF-II Upgrade at Brookhaven National Laboratory	electron, laser, photon, experiment	554
	M.G. Fedurin, M. Babzien, C. Folz, M. Fulkerson, K. Kusche, J.J. Li, R. Malone, M.A. Palmer, T.V. Shaftan, J. Skaritka, L. Snydstrup, C. Swinson, F.J. Willeke BNL, Upton, Long Island, New York, USA
	Funding: Work supported by the US DOE under contract DE-SC0012704. The Accelerator Test Facility (ATF) at Brookhaven National Laboratory (BNL) is presently carrying out an upgrade, ATF-II, which will provide significantly expanded experimental space and capabilities for its users. One of the new capabilities being integrated into the ATF-II program is an Ultrafast Electron Diffraction (UED) beam line, which was originally deployed in the BNL Source Development Laboratory. Inclusion of the UED in the ATF-II research portfolio will enable ongoing development and extension of the UED capabilities for use in materials research. We describe the design, operation and future plans for the UED beam line at the ATF-II.
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MOPIK032	Commissioning of the AISHa Ion Source at INFN-LNS	ion, ion-source, plasma, injection	570
	L. Celona, G. Castro, F. Chines, G. Costa, S. Gammino, O. Leonardi, S. Marletta, D. Mascali, A. Maugeri, L. Neri, F. Noto, S. Passarello, G. Pastore, A. Seminara, G. Torrisi, S. Vinciguerra INFN/LNS, Catania, Italy S. Di Martino, P. Nicotra Si.A.Tel SRL, Catania, Italy
	At INFN-LNS the commissioning of the AISHa superconducting ECRIS started in November 2016. Highly charged ion beams with low ripple, high stability and high reproducibility are the most important features for the ongoing commissioning. In this work, we will show the preliminary results of a parametric study on the extracted current/beam in order to minimize the emittance and increase the brightness taking advantage by its hybrid magnetic system and by a fine frequency tuning system.
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MOPIK033	The Development of a New Low Field Septum Magnet System for Fast Extraction in Main Ring of J-PARC	septum, feedback, extraction, power-supply	573
	T. Shibata, K. Ishii, H. Matsumoto, N. Matsumoto, T. Sugimoto KEK, Ibaraki, Japan K.J. Kuanjun HUST, Wuhan, People's Republic of China
	The J-PARC Main Ring (MR) is being upgraded to improve its beam power to the design goal of 750 kW. One important way is to reduce the repetition period from 2.48 s to 1.3 s so that the beam power can be nearly doubled. We need to improve the septum magnets for fast extraction. We are improving the magnets and their power supplies. The present magnets which is conventional type have problem in durability of septum coil by its vibration, and large leakage field. The new magnets are eddy current type. The eddy current type does not have septum coil, but has a thin plate. We expect that there is no problem in durability, we can construct the thin septum plate, the leakage field can be reduced. The output of the present power supply are pattern current which of flat top is 10 ms width, the new one is short pulse which of one is 10 us. The short pulse consists of 1st and 3rd higher harmonic. We can expect that the flatness and reproducibility of flat top current can be improved. The calorific power can be also reduced. This paper will report the field measurement results with the eddy septum magnet systems.
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MOPIK034	The New High Field Injection Septum Magnet System for Main Ring of J-PARC	septum, injection, power-supply, flattop	576
	T. Shibata, K. Ishii, H. Matsumoto, N. Matsumoto, T. Sugimoto KEK, Ibaraki, Japan K. Fan HUST, Wuhan, People's Republic of China
	We are improving the Main Ring (MR) for beam power of 750 kw which is the first goal of J-PARC. The repetition period of the fast extraction must be short to 1.3 second from the current period of 2.48 second for the improvement of the beam power. We exchanged a injection septum magnet which are located at the injection line from RCS to MR and its power supply in summer of 2016. It was necessary to exchange, because the previous injection septum system can not be operated with 1.3 second repetition. The development of the new injection septum magnet and its power supply in which the maximum repetition are 1Hz and the order od the leakage field are 10^-4 of the gap field were completed in 2016. In this presentation, we will report the final results of its performance, e.g. the magnetic fields and stability of the output current and field, and the beam performance after installation in MR with the new injection magnet.
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MOPIK035	New Injection Scheme of J-PARC Rapid Cycling Synchrotron	injection, proton, synchrotron, shielding	579
	K. Yamamoto, H. Harada, H. Hotchi, J. Kamiya, P.K. Saha, T. Takayanagi, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan N. Miki, O. Takeda Nippon Advanced Technology Co., Ltd., Tokai, Japan
	The 3-GeV Rapid Cycling Synchrotron (RCS) of Japan Proton Accelerator Research Complex (J-PARC) aims to deliver 1-MW proton beam to the neutron target and Main Ring synchrotron (MR). Present beam power of RCS is up to 500-kW and the higher radiation doses were concentrated in the injection area. These activations were caused by the interaction between the foil and the beam. To reduce the worker dose near the injection point, we have studied new design of the injection scheme to secure enough space for radiation shielding and bellows. In the new system, two of four injection pulse bump magnets are replaced and we are able to ensure the additional 500 mm space at the injection foil .
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MOPIK038	Initial Operation of the Low-Flux Proton Beamline at the KOMAC 100 MeV Linac	proton, target, octupole, vacuum	585
	S.P. Yun, C.R. Kim, D.I. Kim, H.S. Kim, H.-J. Kwon, S.G. Lee, Y.G. Song Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea
	Funding: This work was supported by the Ministry of Science, ICT and Future Planning of the Korean Government Korea multi-purpose Accelerator Complex (KOMAC) has been operating 20 MeV and 100 MeV proton beamlines to provide proton beams to users since 2013. The new beamline and target irradiation facility, which is proposed applicable to development of the detector and simulation of the space radiation, have being constructed for low-flux proton utilization at this year. The new beam lines have the 100 MeV of maximum beam energy and 10 nA of maximum beam current. The new beam line was designed to operate with maximum duty 8%, the flux density of proton beam can be reduced to the 1/10,000 by the graphite collimator. The extracted proton beam energy can be adjustable by the double wedge type energy degrader and also, the beam energy can be selected by dipole magnet. In addition to the two sets of the octupole magnets were prepared for uniform beam irradiation with the ± 5% uniformity. In this paper, the initial operation results of the constructed new beam line is be described.
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MOPIK047	Commissioning and Results of the Half-Sector Test Installation with 160 MeV H⁻ beam from Linac4	injection, linac, proton, vacuum	619
	B. Mikulec, D. Aguglia, J.C. Allica Santamaria, C. Baud, C. Bracco, S. Burger, G. Guidoboni, L.O. Jorat, C. Martin, A. Navarro Fernandez, R. Noulibos, F. Roncarolo, J.L. Sanchez Alvarez, J. Tan, T. Todorcevic, P. Van Trappen, W.J.M. Weterings, C. Zamantzas CERN, Geneva, Switzerland
	During the Long Shutdown 2 (LS2) at CERN in 2019/20, the Proton Synchrotron Booster (PSB) will undergo a profound upgrade in the framework of the LHC Injector Upgrade (LIU) project involving also the connection to the new Linac4 injector. The 160 MeV Linac4 H' injection entails a complete replacement of the PSB injection section, including a stripping foil system, injection chicane, an H⁰/H' dump and novel beam instrumentation. The equivalent of half of this new injection chicane was temporarily installed in the Linac4 transfer line to evaluate the performance of the equipment and prepare controls, interlocks and applications for the connection. Outcomes of this so-called Half-Sector Test (HST) are presented in this paper.
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MOPIK065	Status of the Development of a BE-Model-Based Program for Orbit Correction at the Electron Storage Ring DELTA	storage-ring, closed-orbit, hardware, synchrotron	673
	S. Koetter, B. Riemann, T. Weis DELTA, Dortmund, Germany
	A new program for orbit correction is currently being developed at the electron storage ring DELTA. Based upon the standard approach of utilizing the linear response of a closed orbit to dipole-field-strength variations, proposed features include a live-updated orbit-response-matrix model and the integration of the Closed-Orbit-Bilinear-Exponential-Analysis algorithm (COBEA) to clean measured orbit-response matrices from noise. This work focuses on the current status of development of the aforementioned program. After an assessment of the situation at DELTA, first measurements are shown along with numerical convergence studies.
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MOPIK085	Linear Optics Calibration at the HLS-II Storage Ring Using Model Independent Analysis	storage-ring, optics, lattice, experiment	727
	G. Liu, L. Wang, F.F. Wu, K. Xuan USTC/NSRL, Hefei, Anhui, People's Republic of China
	Linear optics are the main lattice parameters characterizing the linear properties of storage rings. Especially for beta function and phase advance, they are the basic lattice functions which must be accurately calibrated to ensure high quality operation of the machine. Model Independent Analysis (MIA), which adopts mathematical statistical methods to extract the effective lattice information of storage rings by directly analyzing the turn-by-turn beam-position-monitor (BPM) measurements, has been applied at HLS-II to calibrate the linear optics model of the storage ring. The measurements of the turn-by-turn BPM data with all of the 32 BPMs are reported in this paper. The calibration results of the beta function using MIA are presented.
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MOPIK098	Techniques for Achieving High Reliability Operation of the Spallation Neutron Source High Power Radio-Frequency System	klystron, cathode, cavity, neutron	756
	J. Moss, M.S. Champion ORNL, Oak Ridge, Tennessee, USA
	Funding: *ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This research was supported by the DOE Office of Science, Basic Energy Science, Scientific User Facilities. The Spallation Neutron Source (SNS) high power radiofrequency (HPRF) system operates with high reliability to support the goals of the SNS user program. In recent operational periods the availability of the HPRF System has exceeded 97 percent while the neutron source availability overall is typically greater than 90 percent. SNS has a unique set of 92 HPRF stations that operate at either 402.5 MHz or 805 MHz with peak output power ranging from 550 kW to 5 MW and average power ranging from 49.5 kW to 450 kW. The HPRF transmitters consist of chassis-mounted power supplies, solid-state amplifiers and other equipment that support the operation of the klystrons that ultimately provide the RF power to the accelerating structures. Management of the operation and maintenance of the HPRF system has increasingly focused on reliability and sustainability in recent years. Techniques for klystron lifetime preservation and optimization of transmitter reliability have been developed and will be described.
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MOPIK102	Beam Dynamics Studies of the HIE-ISOLDE Transfer Lines in the Presence of Magnetic Stray Fields	quadrupole, experiment, shielding, solenoid	768
	J. Mertens, J. Bauche, M.A. Fraser, B. Goddard, R. Ostojić, J.S. Schmidt CERN, Geneva, Switzerland
	The ISOLDE facility at CERN produces radioactive isotopes far from stability for fundamental nuclear physics research. The radioactive beams are accelerated to high-energy using a post-accelerator before being transferred for study in different experiments at the end of a network of High Energy Beam Transfer (HEBT) lines. In the framework of the HIE-ISOLDE project, the energy of post-accelerated beams is to be increased to over 10 MeV/u and new experimental detectors are being proposed for installation to exploit the new energy regime. The stray magnetic fields associated with many of the new detectors will distort the beam trajectories in the HEBT, potentially affecting the transmission of the low intensity beams delivered to the experiments. In this contribution, the influence on the HEBT of the stray field of the proposed ISOL Solenoidal Spectrometer is discussed, correction schemes described and shielding options assessed.
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MOPIK103	Operation with Carbon Stripping Foils at ISIS	injection, electron, synchrotron, emittance	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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MOPIK126	Establishing a Project Management Office for the Large Scale Multi Project FAIR	project-management, site, controls, interface	835
	F. Becker, S. Deveaux, A. Fröhlich, G. Hickler, M. Lautenschläger, M. Raponi, B. Schoenfelder, M. Strangmann, N. Winters GSI, Darmstadt, Germany J.R. Regler, D. Urner FAIR, Darmstadt, Germany
	The Facility for Antiproton and Ion Research (FAIR) is a large scale multi project comprising 10 subprojects in the field of accelerators (pLINAC, SIS100, SuperFRS, p-bar Separator, Collector Ring, High Energy Storage Ring), experiments (CBM, APPA, NUSTAR, PANDA) and civil construction. This contribution describes an integrated approach how a controlling type project management office (PMO) was established, meeting the overall requirements for project steering and specific requirements of the subprojects and international partners involved. Major responsibilities of the PMO are project planning, integrated reporting, cost and budget control, risk management, in-kind coordination & procurement, quality assurance & configuration management. Core processes, roles and responsibilities, methodology and interfaces internally and towards the project pillars are presented.
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MOPVA013	Application of Non-Isochronous Beam Dynamics in ERLs for Improving Energy Spread and Beam Stability	linac, electron, acceleration, recirculation	873
	F. Hug IKP, Mainz, Germany
	Funding: Work supported by DFG through the PRISMA cluster of excellence EXC 1098/2014 and Research Training Group GRK 2128 Non-isochronous recirculation is the common operation mode for synchrotrons or microtrons. In such a non-isochronous recirculation scheme the recirculation paths provide a non-zero longitudinal dispersion while the accelerating field is operated at a certain phase off-crest with respect to the maximum. In few turn linacs like ERLs and in microtrons non-isochronous beam dynamics can be used to reduce the energy spread by cancelling out any rf-jitters coming from the linac cavities. To do so the longitudinal phase advance needs to be tuned to a half-integer number of oscillations in longitudinal phase space. Then the total energy spread after main linac acceleration conserves the value at injection. In addition to the improved energy spread the beam stability of few-turn recirculators can be increased as well using such a system. Such concept provides an inherent beam stability and has been introduced many years ago [] and proven to work successfully in a few-turn recirculator already []. We will present beam dynamics calculations for the application of nonisochronous beam dynamics in single- and multi-turn energy recovery linacs at different longitudinal working points. [] H. Herminghaus, NIM. A 314 (1992) 209. [**] F. Hug et al., Proc. of LINAC '12 (2012) 531.
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MOPVA014	Injector Linac Stability Requirements for High Precision Experiments at MESA	experiment, linac, electron, acceleration	876
	F. Hug, R.G. Heine IKP, Mainz, Germany
	Funding: Work supported by DFG through the PRISMA cluster of excellence EXC 1098/2014 and Research Training Group GRK 2128 MESA is a recirculating superconducting accelerator under construction at Johannes Gutenberg-Universität Mainz. It will be used for high precision particle physics experiments in two different operation modes: external beam (EB) mode and energy recovery (ERL) mode. The operating beam current and energy in EB mode is 0.15 mA with polarized electrons at 155 MeV. In ERL mode an unpolarized beam of 1 mA at 10⁵ MeV will be available. In a later construction stage of MESA the beam current in ERL-mode shall be upgraded to 10 mA. In order to achieve high beam stability and low energy spread in recirculating operation the acceleration in the main linac sections will be done on edge of the accelerating field while the return arcs provide longitudinal dispersion. On certain longitudinal working points this can result in a setting where rf jitters from main linac do not contribute to the resulting energy spread of the final beam at all [,]. Then the resulting energy spread is only determined by the energy spread provided by the inector linac. Within this contribution we will investigate the requirements on the stability of the MESA injector linac MAMBO for achieving the experimental goals. [] H. Herminghaus, NIM. A 314 (1992) 209. [**] F. Hug et al., Proc. of LINAC '12 (2012) 531.
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MOPVA019	60 pC Bunch Charge Operation of the Compact ERL at KEK	emittance, 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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MOPVA021	Optics Design of the Compact ERL Injector for 60 pC Bunch Charge Operation	optics, cathode, laser, gun	898
	T. Hotei Sokendai, Ibaraki, Japan R. Kato, T. Miyajima, N. Nakamura, M. Shimada KEK, Ibaraki, Japan
	EUV-FEL light source based on ERL has been designed at KEK for EUV lithography light source. The advantage of ERL is to accelerate high average current beam due to CW operation, and it is possible to drive high average power FEL. To generate the target EUV-FEL power, which is 10 kW, the bunch charge of 60 pC, the beam energy of 10.5 MeV and the bunch length of 1 ps are required at the end of the EUV-FEL injector. In order to demonstrate the target beam performance for the EUV-FEL accelerator, a high charge beam test was carried out at the cERL in KEK. We designed a new optics of the cERL injector prior to the high charge beam operation. To calculate beam dynamics more accurately, accelerator models corrected according to the condition of the actual cERL injector is used for the optics design. From results of the optics design that minimized the emittance and bunch length using the corrected accelerator models, the emittance and bunch length at the end of injector are 0.8 mm-mrad and 3.4 ps. Furthermore, based on the design optics, we carried out high bunch charge beam operation.
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MOPVA039	Manufacturing and Validation Tests of IFMIF Low-Beta HWRs	cavity, cryomodule, SRF, simulation	942
	G. Devanz, F. Éozénou, L. Maurice, P. Sahuquet, C. Servouin CEA/DSM/IRFU, France N. Bazin, P. Carbonnier, P. Charon, G. Disset, P. Hardy, E. Jacques, O. Piquet, D. Roudier CEA/IRFU, Gif-sur-Yvette, France J.K. Chambrillon, T. Percerou CEA/DRF/IRFU, Gif-sur-Yvette, France
	The IFMIF accelerator aims to provide an accelerator-based D-Li neutron source to produce high intensity high energy neutron flux to test samples as possible candidate materials to a full lifetime of fusion energy reactors. A prototype of the low energy part of the accelerator is under construction at Rokkasho in Japan. It includes one cryomodule containing 8 half-wave resonators (HWR) operating at 175 MHz .The first manufactured HWR has passed low power tests at 4.2K in vertical cryostat succesfully and exceeds the specifications. It has also been tested in the dedicated horizontal Sathori cryostat equiped with its cold tuning system. The serial production and qualification tests of the 8 cavities which will eventually equip the cryomodule are carried out in parallel. In this paper, we focus on the HWR preparation and test results and give a status of the manufacturing activities.
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MOPVA048	Simulation of the Thermoelectrically Generated Magnetic Field in a SC Nine-Cell Cavity	cavity, simulation, SRF, superconducting-RF	968
	J.M. Köszegi, J. Knobloch, O. Kugeler HZB, Berlin, Germany
	Several studies showed that thermocurrents generate a magnetic field in a horizontal cavity test assembly or cryomodul, which may get trapped during the supercon-ducting phase transition. The trapped flux causes additional dissipation in the order of 1 to 10 n' during operation and can therefore significantly degrade the quality factor in a TESLA cavity. We simulated the distribution of the generated magnetic field over the whole cavity-tank system for an asymmetric temperature distribution. The asymmetry allows the field to penetrate the RF surface which would be field free in the symmetric case. The calculated results complemented a direct measurement of trapped magnetic flux inside the cavity with a small number of field probes. Finally, the obtained data was combined with RF measurements in three passband modes to determine the overall distribution of trapped magnetic flux due to thermocurrents.
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MOPVA051	Design of the High Power 1.5 GHz Input Couplers for BESSY VSR	coupling, cavity, simulation, HOM	978
	E. Sharples, M. Dirsat, J. Knobloch, A.V. Vélez HZB, Berlin, Germany
	The Variable pulse length Storage Ring (BESSY VSR) upgrade to BESSY II at Helmholtz-Zentrum Berlin (HZB) requires an upgrade on the RF systems in the form of high-voltage longitudinally focusing super conducting RF cavities of 1.5 GHz ad 1.75 GHz. For operation, coaxial RF power couplers capable of handling 13 kW peak power at standing wave operation are required for both the 1.5 GHz and 1.75 GHz cavities. The coupler is based on a design by Cornell University with modifications to suit frequency and coupling requirements. The coupler is intended to provide variable coupling with a range of Qext from 6x10⁶ to 6x10⁷ to allow flexibility to adjust to operating conditions of BESSY VSR. Here we present the RF design of the high-power coaxial coupler for BESSY VSR along with the design of the test stand for conditioning a pair of couplers.
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MOPVA052	Study on HOM Power Levels in the BESSY VSR Module	HOM, cavity, SRF, resonance	982
	A.V. Tsakanian, H.-W. Glock, J. Knobloch, A.V. Vélez HZB, Berlin, Germany
	The BESSY VSR upgrade of the BESSY II light source represents a novel approach to simultaneously store of long (ca. 15ps) and short (ca. 1.5ps) bunches in the storage ring with the 'standard' user optics. This challenging goal requires installation of four new SRF cavities (2x1.5GHz and 2x1.75GHz) in a single module to minimize space requirements. These cavities are equipped with strong waveguide and beam tube HOM dampers necessary for stable operation. The expected HOM power and spectrum has been analyzed for the complete module. This study is performed for various BESSY VSR bunch filling patterns with 300 mA beam current. In the module different cavity arrangements are analyzed to reach the optimal operation conditions with equally distributed power portions in warm HOM loads and tolerable beam coupling impedance.
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MOPVA055	Upgrade of the Capture Section of the S-DALINAC Injector	cavity, SRF, electron, accelerating-gradient	993
	D.B. Bazyl, H. De Gersem, W.F.O. Müller TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: This work is supported by the DFG through GRK 2128. In order to reduce the energy spread of the recirculated beam, the injector of the S-DALINAC needs to be optimized, because the non-isochronous recirculation cannot correct for errors originating from the injector linac. For the S-DALINAC, spatial restrictions suggest the use of SRF technology for the capture section. In this work, we consider various SRF cavities with an operating frequency of 3 GHz for a possible upgrade of the capture section of the S-DALINAC. The first results of the RF and beam dynamics simulations for the proposed options are presented in this paper.
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MOPVA058	Commissioning and Operation Experience of the 3.9 GHz System in the EXFEL Linac	cavity, LLRF, linac, klystron	999
	C.G. Maiano, J. Branlard, M. Hüning, M. Omet, P. Pierini, E. Vogel DESY, Hamburg, Germany A. Bosotti, R. Paparella, P. Pierini, D. Sertore INFN/LASA, Segrate (MI), Italy
	The European X-ray Free Electron Laser (EXFEL) injector linac hosts a 3.9~GHz module (AH1) for beam longitudinal phase space manipulation after the first acceleration stage, in order for the linac to deliver the high current beams with sufficiently low emittance for the production of 1 Angstrom FEL light to the experimental users. The module was technically commissioned in December 2015 and operated well above its nominal performances during the Injector Run from January to July 2016. Its operation has restarted in January 2017 with the startup of the whole facility, and the system met the design beam specifications after the bunch compression stages. A brief review of the commissioning and first operation experience of the RF system are presented here.
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MOPVA060	Fabrication and Treatment of the ESS Medium Beta Prototype Cavities	cavity, controls, feedback, vacuum	1003
	L. Monaco, A. Bellandi, M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, P. Michelato, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy S. Pirani ESS, Lund, Sweden
	In view of the Medium Beta series cavities production at the industry for the European Spallation Source project, INFN Milano - LASA design prototypes have been fully produced at Ettore Zanon S.p.A. with our supervision. Based on our experience on the production of 1.3 GHz and 3.9 GHz E-XFEL series cavities, we set-up and applied an external quality control activity of the overall production of the prototype cavity, starting from the row materials to the ready to be tested cavity. In this paper, we report the strategy we have adopted on the overall production, mechanical and surface treatments, frequency measurement of subcomponents and cavities and the obtained results.
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MOPVA063	Vertical Tests of ESS Medium Beta Prototype Cavities at LASA	cavity, vacuum, radiation, accelerating-gradient	1015
	A. Bosotti, A. Bellandi, M. Bertucci, A. Bignami, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, R. Paparella, P. Pierini, D. Sertore INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy S. Pirani ESS, Lund, Sweden
	In the framework of the INFN activity related to the European Spallation Source collaboration, the LASA infrastructure has been renewed to allow the qualification, in its vertical cryostat, of the 704 MHz medium beta cavity prototypes. A new cryogenic insert has been realized, fully equipped with dedicated mechanical supports, vacuum, thermal sensors and quench diagnostic systems. The RF test station has been upgraded as well with a new PLL electronics rack. The first beta 0.67 cavity prototype designed and produced by INFN Milano has been successfully cold tested at 2.0 K temperature, outperforming the ESS specifications. The technical features of LASA infrastructure, the design of novel components and the experimental results of cavities cold-tests are thoroughly described in this paper.
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MOPVA066	Limits for the Operation of the European XFEL 3.9 GHz System in CW Mode	cavity, cryomodule, linac, laser	1023
	P. Pierini, A. Bosotti, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy J. Branlard, D. Kostin, C.G. Maiano, W.-D. Möller, P. Pierini, D. Reschke, J.K. Sekutowicz, E. Vogel DESY, Hamburg, Germany
	Future upgrades of the European XFEL (EXFEL) facility may require driving the linac at higher duty factor, possibly extending to CW mode at reduced gradients. A preliminary analysis for the accelerator modules has been presented in the EXFEL TDR, but no precise assessment has been performed so far for the present 3.9 GHz system design. By making use of data collected during the commissioning and operation phase of the EXFEL injector system, we discuss here an estimate for the limits of CW operation of the present system and a plan for its possible experimental verification with existing available cavities and the EXFEL spare module.
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MOPVA068	Experience on Design, Fabrication and Testing of a Large Grain ESS Medium Beta Prototype Cavity	cavity, radiation, niobium, cryogenics	1027
	D. Sertore, A. Bellandi, M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, R. Paparella, P. Pierini INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy S. Pirani ESS, Lund, Sweden
	We report on the design, fabrication and testing of an ESS Medium Beta prototype cavity made with Large Grain Niobium sheets sliced from an ingot provided by CBMM. The peculiar choices during the fabrication process related to the Large Grain Niobium material are described. We present also the results of the cavity test at cryogenic temperature and the dedicated quench diagnostic.
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MOPVA073	Development of Peak Hold Module for Electron Emission in STF-Type Power Coupler for the ILC	electron, vacuum, cryomodule, monitoring	1034
	Y. Yamamoto, E. Kako, T. Shishido KEK, Ibaraki, Japan
	In STF, the RF conditioning for power coupler is done in several steps from 10 to 1650 μs as specified in TDR for the ILC. The most important signals during the RF conditioning are vacuum level, and electron emission by multipacting. The vacuum level changes continuously, and electron emission has pulse-like behavior, which has much faster response. Therefore, it was necessary to develop the peak hold and isolation modules to evaluate electron emission in short pulse width. This module has two kinds of feature. One is pulse height detection, and the other is total charge detection (integrated signal). During the RF conditioning for power couplers in STF-2 cryomodule, this module perfectly worked, and detected different trend between the pulse height and the total charge. In this paper, the detailed result for the peak hold module will be presented.
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MOPVA075	Development of High Sensitive X-Ray Mapping for SC Cavities	cavity, survey, interface, cryogenics	1040
	H. Tongu, H. Hokonohara, Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan R.L. Geng, A.D. Palczewski JLab, Newport News, Virginia, USA H. Hayano, T. Kubo, T. Saeki, Y. Yamamoto KEK, Ibaraki, Japan H. Oikawa Utsunomiya University, Utsunomiya, Japan
	We developed an X-ray mapping system sX-map for superconducting cavities. The sensors are inserted under the stiffener rings between cavity cells, whose locations are close to the iris areas. The whole circuits are im-mersed in liquid He and the multiplexed signals reduces the number of cables to the room temperature region. sX-map has the advantages in its compact size, low cost and simple setup for nondestructive inspections. The sX-map system detected X-rays from field emissions in vertical RF tests of ILC 9-cell cavities at Jefferson Lab (JLab) and KEK. sX-map showed an excellent performance in the meas-urement test at JLab, it exhibited a high sensitivity com-pared with an the fixed diode rings colocated at irises and ion chamber located out side of the vertical test cryostat.
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MOPVA078	The Window Replacement and Q Recovery of BEPCII Storage Ring SCC	cavity, vacuum, positron, radiation	1046
	T.M. Huang, J.P. Dai, R. Ge, S.P. Li, Z.Q. Li, H.Y. Lin, Q. Ma, W.M. Pan, Y. Sun, G.W. Wang IHEP, Beijing, People's Republic of China P. Sha Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	The storage ring RF system for the upgrade of the Beijing Electron Positron Collider (BEPCII) adopted two 500 MHz superconducting cavities: west for the positron ring (BPR); east for the electron ring (BER). The excessive heating of the west window was observed in Nov.2013, and not cured thoroughly. After two years operation, the window cracked suddenly on Nov.18th, 2015. The replacement of the window was subsequently implemented in tunnel. However, the quality factor (Q) of the cavity decayed a lot after the window replacement. 90 degrees Celsius N2 gas baking of the outer surface of the cavity was carried out in situ and the Q recovered in a short time. This paper will present the process of the window replacement and the cavity Q recovery in detail. Tong-ming Huang et al., Chinese Physics C Vol. 40, No. 6 (2016) 067001
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MOPVA091	Investigation of HOM Frequency Shifts Induced by Mechanical Tolerances	cavity, HOM, simulation, cryogenics	1071
	S. Pirani, M. Eshraqi, M. Lindroos ESS, Lund, Sweden A. Bosotti, J.F. Chen, P. Michelato, C. Pagani, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy T.P.Å. Åkesson Lund University, Department of Physics, Lund, Sweden
	We present Higher Order Mode (HOM) studies on ESS Medium-Beta cavity of INFN-LASA design, including both simulation and measurement results. Mechanical tolerances of the fabrication process might shift HOMs frequencies toward harmonics of the bunch frequency. Both simulation and measurements at room and cryogenic temperature show that INFN LASA cavity is fully compatible with ESS requirements.
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MOPVA095	First RF Performance Results for the DQW Crab Cavities to be Tested in the CERN SPS	cavity, SRF, monitoring, cryomodule	1077
	A. Castilla, R. Calaga, O. Capatina, K.M. Dr. Schirm, K.G. Hernández-Chahín, A. Macpherson, N.C. Shipman, K. Turaj CERN, Geneva, Switzerland I. Ben-Zvi BNL, Upton, Long Island, New York, USA G. Burt, J.A. Mitchell Lancaster University, Lancaster, United Kingdom K.G. Hernández-Chahín DCI-UG, León, Mexico N.C. Shipman Cockcroft Institute, Lancaster University, Lancaster, United Kingdom N.C. Shipman UMAN, Manchester, United Kingdom
	As part of the High Luminosity LHC (HL-LHC) project strategy, crab cavity correctors shall be installed around CMS and ATLAS experiments of the LHC. To accommodate the different crossing angle planes, two distinct cavity designs have been selected: the RF Dipole (RFD) and the Double Quarter Wave resonator (DQW). CERN has fabricated two double quarter wave resonators (DQW_SPS), for validation with a proton beam at the CERN SPS accelerator. Standard superconducting rf surface preparation protocols have been applied to the two bulk niobium cavities, followed by cryogenic testing in a vertical cryostat at CERN's SM18 facility. The performance results obtained after the first bare cavity tests for cavities DQW_SPS₀01 and DQW_SPS₀02 are shown in this paper, and include Q0 vs Vt curves, Lorentz Force Detuning (LFD) analyses and pressure sensitivity of a higher order mode.
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MOPVA098	Strategy Towards Non-Interrupted Operation of Superconducting Radio Frequency Modules at NSRRC	SRF, vacuum, cryogenics, cavity	1088
	Ch. Wang, F.Y. Chang, L.-H. Chang, M.H. Chang, J. Chen, L.J. Chen, F.-T. Chung, M.-C. Lin, Z.K. Liu, C.H. Lo, C.L. Tsai, M.-S. Yeh, T.-C. Yu NSRRC, Hsinchu, Taiwan
	Two modern 3rd generation light sources, the well-developed 1.5-GeV Taiwan Light Source (TLS) and the new constructed 3-GeV Taiwan Photon Source (TPS), are now in routine operation. Both storage rings are powered by the superconducting RF (cavity) modules, one CESR-type SRF module for the TLS since 2005 and two KEKB-type SRF modules for the TPS since 2014. Thanks to continuous efforts, the operational reliability of SRF modules at NSRRC is now compatible or better in comparison with the best operation record of room temperature cavities ever achieved at TLS (1992-2004). How to improve the long term availability but hold the achieved reliability of SRF modules such as to maximize the available annual user beam time, especially, under requirements on high RF power operation, become a new operational challenge, especially for the SRF modules at TPS which is now routinely operated with a forward RF power around 150-kW individually and expected to push to 300-kW in the coming future. Here we report our strategy and achievement to minimize long term interrupt of SRF operation owing to regular full-thermal cycling and annual maintenance of cryogenic plant.
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MOPVA099	The Study of Electromagnet Compensated High Power Ferrite Circulator Operation With Superconducting RF Cavity	cavity, SRF, klystron, vacuum	1091
	T.-C. Yu, F.Y. Chang, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Z.K. Liu, C.H. Lo, C.L. Tsai, M.H. Tsai, Ch. Wang, M.-S. Yeh NSRRC, Hsinchu, Taiwan
	In a high power RF system for accelerator application, the circulator is very important for protecting klystron or IOT from damage due to high reflection power from the cavity. When there is no beam current passing through the superconducting RF cavity of the accelerator, almost 100% RF power will be reflected from the cavity even the cavity is on resonance. The circulator shall be able to forward the reflected power to the load and remain good matching and isolation condition between ports at klystron and the cavity. However, for a ferrite material based circulator, the magnetic field within circulator would be temperature dependent which would cause the variation of input return loss and isolation between ports. Additional DC current driving electromagnet field is thus re-quired for compensating the temperature variation. Even with the compensating DC current, the circulator is still not ideal for practical operation especially when the performance of the circulator is strongly phase dependent. The phenomenon observed in actual operation with one set of SRF systems in NSRRC is thus reported in this article.
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MOPVA118	Impact of Trapped Magnetic Flux and Thermal Gradients on the Performance of Nb3Sn Cavities	cavity, niobium, site, target	1127
	D.L. Hall, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA D. Liarte, J.P. Sethna Cornell University, Ithaca, New York, USA
	Trapped magnetic flux is known to degrade the quality factor of superconducting cavities by increasing the surface losses ascribed to the residual resistance. In Nb3Sn cavities, which consist of a thin layer of Nb3Sn coated on a bulk niobium substrate, the bimetallic interface results in a thermal current being generated in the presence of a thermal gradient, which will in turn generate flux that can be trapped. In this paper we quantify the impact of trapped flux, from either ambient fields or thermal gradients, on the performance of the cavity. We discover that the sensitivity to trapped flux, a measure of the increase in residual resistance as a function of the amount of flux trapped, is a function of the accelerating gradient. A theoretical framework to explain this phenomenon is proposed, and the impact on the requirements for operating a Nb3Sn cavity in a cryomodule are considered.
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MOPVA122	Microphonics Studies of the CBETA Linac Cryomodules	cavity, cryomodule, linac, SRF	1138
	N. Banerjee, J. Dobbins, F. Furuta, D.L. Hall, G.H. Hoffstaetter, M. Liepe, P. Quigley, E.N. Smith, V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work was performed through the support of NYSERDA (New York State Energy Research and Development Agency). The Cornell BNL ERL Test Accelerator (CBETA) incorporates two SRF linacs; one for its injector and another for the energy recovery loop. Microphonics in both the cryomodules play a crucial role in determining the energy stability of the electron beam in high current operation. We have measured vibrations and frequency detuning of the SRF cavities and determined that the cryogenic system is the major source of microphonics in both cryomodules. In this paper we discuss these measurements and demonstrate an Active Microphonics Compensation system implemented using fast piezo-electric tuners which we incorporated in our Low Level RF control system to be used in routine operation.
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MOPVA123	Cornell Sample Host Cavity: Recent Results	cavity, niobium, SRF, electron	1142
	J.T. Maniscalco, D.L. Hall, M. Liepe, R.D. Porter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V.M. Arrieta, S.R. McNeal, W.E. Williams Ultramet, Pacoima, California, USA
	Funding: NSF-PHY 1416318 NSF-PHY 1549132 The Cornell sample host cavity is a 3.9~GHz testing system for RF analysis of novel superconducting surfaces. The cavity applies fields up to 100~mT on a removable and replaceable 5-inch sample plate in order to measure the surface resistance of the material under investigation. The cavity also includes a temperature-mapping system for localization of quench events and surface defects. In this paper, we present recent experimental results from the host cavity of niobium deposited onto molybdenum and copper substrates using chemical vapor deposition, in collaboration with industry partner Ultramet. The results indicate low BCS resistance and good adhesion but also areas of high residual resistance due to chemical and morphological defects.
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MOPVA128	RF Performance of Nitrogen-Doped Production SRF Cavities for LCLS-II	cavity, SRF, niobium, accelerating-gradient	1156
	D. Gonnella, A. Burrill, M.C. Ross SLAC, Menlo Park, California, USA S. Aderhold, A. Grassellino, C.J. Grimm, T.N. Khabiboulline, O.S. Melnychuk, S. Posen, D.A. Sergatskov Fermilab, Batavia, Illinois, USA E. Daly, G.K. Davis, F. Marhauser, K.M. Wilson JLab, Newport News, Virginia, USA
	Funding: DOE and the LCLS-II Project The Linac Coherent Light Source II (LCLS-II) requires 280 9-cell superconducting RF cavities for operation in continuous wave mode. Two vendors have previously been selected to produce the cavities, Research Instruments GmbH and Ettore Zanon S.p.a. Here we present results from manufacturing and cavity preparation for the cavities constructed at these two vendors for LCLS-II. We show how the cavity preparation method has been changed mid-production in order to improve flux expulsion in the cavities and maintain high performance in realistic magnetic field environments (~5 mG). Additionally, we show that the nitrogen-doping process has been carried out successfully and repeatedly on over 70 cavities.
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MOPVA133	Optimization of the RF Cavity Heat Load and Trip Rates for CEBAF at 12 GeV	linac, cavity, electron, SRF	1170
	H. Zhang, A. Freyberger, G.A. Krafft, Y. Roblin JLab, Newport News, Virginia, USA B. Terzić ODU, Norfolk, Virginia, USA
	Funding: Work supported by the Department of Energy under Contract No. DE-AC05-06OR23177 The Continuous Electron Beam Accelerator Facility at JLab has 200 RF cavities in the north linac and the south linac respectively after the 12 GeV upgrade. The purpose of this work is to simultaneously optimize the heat load and the trip rate for the cavities and to reconstruct the pareto-optimal front in a timely manner when some of the cavities are turned down. By choosing an efficient optimizer and strategically creating the initial gradients, the pareto-optimal front for no more than 15 cavities down can be re-established within 20 seconds.
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MOPVA143	Trim Tuning of SPS-Series DQW Crab Cavity Prototypes	cavity, target, simulation, controls	1187
	S. Verdú-Andrés, J. Skaritka, Q. Wu BNL, Upton, Long Island, New York, USA S. Baurac, C.H. Boulware, T.L. Grimm, J.A. Yancey Niowave, Inc., Lansing, Michigan, USA W.A. Clemens, E.A. McEwen, H. Park JLab, Newport News, Virginia, USA H. Park ODU, Norfolk, Virginia, USA A. Ratti LBNL, Berkeley, California, USA A. Ratti SLAC, Menlo Park, California, USA
	Funding: Work partially supported by US DOE via BSA LLC contract No.DE-AC02-98CH10886 and by the US LARP program. The final steps in the manufacturing of a superconducting RF cavity involve careful tuning before the final welds to match the target frequency as fabrication tolerances may introduce some frequency deviations. The target frequency is chosen based on analysis of the shifts induced by remaining processing steps including acid etching and cool down. The baseline fabrication of a DQW crab cavity for the High Luminosity LHC (HL-LHC) envisages a first tuning before the cavity subassemblies are welded together. To produce a very accurate final result, subassemblies are trimmed to frequency in the last machining steps, using a clamped cavity assembly for RF measurements. This paper will describe the trim tuning of one of the SPS prototype DQW crab cavities fabricated by Niowave.
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TUOAB3	Development of Wide Dynamic Range Beam Loss Monitor System for the J-PARC Main Ring	detector, beam-losses, injection, extraction	1248
	K. Satou, N. Kamikubota, T. Toyama, S. Yamada J-PARC, KEK & JAEA, Ibaraki-ken, Japan S.Y. Yoshida Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan
	The new beam loss monitor (BLM) system now in operation at the main ring of J-PARC consists of an isolated front-end current to voltage converter, a VME-based 24 bit ADC system. A dual detector system employs a proportional-type gas chamber (PBLM) and an air-filled ionization chamber (AIC). The system shows a wide dynamic range of 160 dB. It can detect the low level signal that would arise in the case of the detection of residual dose in the ring itself after the beam has been turned off as well as an event such as high level beam loss at the collimators. The signal rise time of the waveform obtained is 17 us which fast enough to meet the speed requirement of the Machine Protection System (MPS); which is that the MPS should dump the beam within 100 us when the beam loss signal exceeds the reference levels set in the ADC system.
	Slides TUOAB3 [2.692 MB]
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TUZB1	Final Results From the Clic Test Facility (CTF3)	linac, acceleration, emittance, beam-loading	1269
	R. Corsini CERN, Geneva, Switzerland
	The unique CLIC TEST Facility (CTF3) has been built more than a decade ago to demonstrate the feasibility of the CLIC two beam acceleration scheme. The emphasis was one the high current drive beam generation using a fully loaded highly efficient linac and a complex combination scheme to increase beam current and bunch repetition frequency. This drive beam has been used for deceleration experiments and two beam acceleration. A wealth of relevant results for accelerator physics even beyond CLIC has been obtained and will be presented. The rf to beam efficiency of the linac exceeds 95%, after combination the 28 A drive beam with 12 GHz bunch repetition rate has been used to extract more than 50% of its energy producing 1.3 GW of 12 GHz power as well as performing two beam acceleration at 12 GHz with gradients up to 150 MV/m.
	Slides TUZB1 [23.702 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUZB1
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TUPAB002	Material Tests for the ILC Positron Source	target, positron, electron, photon	1293
	A. Ushakov, G.A. Moortgat-Pick University of Hamburg, Hamburg, Germany K. Aulenbacher, Th. Beiser, P. Heil, V. Tioukine IKP, Mainz, Germany A. Ignatenko, S. Riemann DESY Zeuthen, Zeuthen, Germany A.L. Prudnikava, Y. Tamashevich University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	The positron source is a vital system of the ILC. The conversion target that yields 10¹⁴ positrons per second will undergo high peak and cyclic load during ILC operation. In order to ensure stable long term operation of the positron source the candidate material for the conversion target has to be tested. The intense electron beam at the Mainz Microtron (MAMI) provides a good opportunity for such tests. The first results for Ti6Al4V are presented which is the candidate material for the positron conversion target as well as for the exit window to the photon beam absorber.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB002
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TUPAB006	Achievement of Stable Pulsed Operation at 31 MV/m in the STF-2 Cryomodule for the ILC	cavity, cryomodule, radiation, accelerating-gradient	1308
	Y. Yamamoto, T. Dohmae, M. Egi, K. Hara, T. Honma, E. Kako, Y. Kojima, T. Konomi, N. Kota, T. Kubo, T. Matsumoto, T. Miura, H. Nakai, K. Nakanishi, G.-T. Park, T. Saeki, H. Shimizu, T. Shishido, T. Takenaka, K. Umemori KEK, Ibaraki, Japan
	In the Superconducting RF Test Facility (STF) in KEK, the cooldown test for the STF-2 cryomodule with 12 cavities has been done totally three times since 2014. In 2016, the 3rd cooldown test for the STF-2 cryomodule including the capture cryomodule with 2 cavities, which was used for Quantum Beam Project in 2012, was successfully done. The main purpose is the vector-sum operation with 8 cavities at average accelerating gradient of 31 MV/m as the ILC specification, and the others are the measurement for Lorenz Force Detuning (LFD) and unloaded Q value, and Low Level RF (LLRF) study, etc. During 8 cavities operation, piezo actuators were used for the compensation of LFD, and the feed-forward and vector-sum control system by LLRF worked perfectly for keeping the lowest forward power and the stable flat-top of accelerating gradient. In this paper, the result for the STF-2 cryomodule in the 3rd cooldown test will be presented in detail.
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TUPAB007	Analysis of the Dependability of the LHC Quench Detection System During LHC Run 2 and Further System Evolution	radiation, software, electronics, superconducting-magnet	1311
	T. Podzorny, D.O. Calcoen, R. Denz, A.P. Siemko, J. Spasic, J. Steckert CERN, Geneva, Switzerland
	The quench detection system (QDS) of the LHC superconducting circuits is an essential part of the LHC machine protection and ensures the integrity of key elements of the accelerator. The large amount of hardwired and software interlock channels of the QDS requires a very high system dependability in order to reduce the risk of affecting the successful operation of the LHC. This contribution will present methods and tools for systematic fault tracking and analysis, and will discuss recent results obtained during the LHC production run in 2016. Measures for maintaining and further improving of the system performance will be explained. An overview of the further evolution of the LHC QDS also in view of the upcoming High Luminosity Upgrade of the LHC will be given.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB007
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TUPAB010	High-Gradient Breakdown Studies of X-Band Choke-Mode Structures	cavity, linac, collider, linear-collider	1322
	X.W. Wu, H.B. Chen, J. Shi, H. Zha TUB, Beijing, People's Republic of China T. Abe, T. Higo, S. Matsumoto KEK, Ibaraki, Japan
	As an alternative design for Compact Linear Collider (CLIC) main accelerating structures, X-band choke-mode damped structures had been studied for several years. However, the performance of choke-mode cavity under high power is still in lack of research. Two standing-wave single-cell choke-mode damped accelerating structures working at 11.424 GHz and one reference structure without choke were designed, manufactured, low-power measured, and tuned by accelerator group at Tsinghua University. High-power test had been done on them to study the breakdown phenomenon in high gradient and how the choke affects high-gradient properties. A max gradient of 75 MV/m were achieved by the choke-mode structure and the choke breakdown limited further increasing of the gradient. Inner surface inspection of the choke-mode structures indicates that the axial part of the choke limits the performance of the structure. Based on this observation, three new choke-mode structures were designed and being manufactured.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB010
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TUPAB016	The CLIC Main Linac Module Updated Design	alignment, linac, klystron, luminosity	1345
	C. Rossi, M. Aicheler, N. Catalán Lasheras, R. Corsini, S. Döbert, A. Grudiev, A. Latina, H. Mainaud Durand, M. Modena, H. Schmickler, D. Schulte, S. Stapnes, I. Syratchev, A.L. Vamvakas, W. Wuensch CERN, Geneva, Switzerland M. Aicheler HIP, University of Helsinki, Finland
	In 2016, CLIC implementation working groups have started their reflection on how to finalize the CLIC design work in the different areas of the project, aiming for a technical design and an overall implementation plan for CLIC being available for the next European Strategy Update around 2019. One of the working groups has focused its attention on the Main Linac hardware, which has brought together the different competences of the study with the aim of producing an advanced set of specifications for the design, installation and operation of the CLIC module. As the fundamental unit for the construction of the Main Beam linac, the CLIC module needs to move from the existing prototypes exploring its performance into an advanced and functional unit where the full life cycle of the module is considered. The progress of the working group activity is summarized in this paper, with considerations on the requirements for the design of the next-phase CLIC module.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB016
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TUPAB017	Results of the Beam-Loading Breakdown Rate Experiment at the CLIC Test Facility CTF3	beam-loading, experiment, klystron, linac	1348
	E. Senes, T. Argyropoulos, N. Catalán Lasheras, R. Corsini, D. Gamba, J. Giner Navarro, A. Grudiev, G. McMonagle, R. Rajamaki, X.F.D. Stragier, I. Syratchev, F. Tecker, W. Wuensch CERN, Geneva, Switzerland J. Giner Navarro IFIC, Valencia, Spain R. Rajamaki Aalto University, School of Science and Technology, Aalto, Finland E. Senes Torino University, Torino, Italy
	The RF breakdown rate is crucial for the luminosity performance of the CLIC linear collider. The required breakdown rate at the design gradient of 100 MV/m has been demonstrated, without beam presence, in a number of 12 GHz CLIC prototype structures. Nevertheless, the beam-loading at CLIC significantly changes the field profile inside the structures, and the behaviour with beam needs to be understood. A dedicated experiment in the CLIC Test Facility CTF3 to determine the effect of beam on the breakdown rate has been collecting breakdown data throughout the year 2016. The complete results of the experiment and the effect of the beam-loading on the breakdown rate are presented.
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TUPAB030	Construction and Status of the Thrice Recirculating S-DALINAC	alignment, recirculation, lattice, dipole	1384
	M. Arnold, R. Grewe, J. Pforr, N. Pietralla TU Darmstadt, Darmstadt, Germany C. Eschelbach, M. Lösler Frankfurt University of Applied Sciences, Frankfurt am Main, Germany F. Hug IKP, Mainz, Germany T. Kürzeder HIM, Mainz, Germany
	Funding: Work supported by DFG through RTG 2128 and CRC 634. From 1991 until 2015 the S-DALINAC (Superconducting-DArmstadt-LINear-ACcelerator) was operated as a twice recirculating electron accelerator. Its design energy of 130 MeV in cw-operation was not reached so far due to a lower quality factor of the SRF cavities and thus a higher dissipated power to the helium bath. In 2015/2016 a third recirculation has been built. Enabling a fourth passage through the main linac, the accelerating gradients can be reduced to fit the resulting dissipated power to the available cooling power for running at design energy. The upgrade to a thrice recirculating accelerator required the reconstruction of main parts of the existing lattice as well as an installation of a new beam line. All magnets had to be aligned carefully in position and orientation using high-precision metrology sensors. This contribution will present an overview of the construction and the alignment process. A latest status of the commissioning will be given.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB030
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TUPAB044	SIMULATION, MEASUREMENT AND TUNING OF A PROTOTYPE DISK LOADED RF CAVITY	electron, simulation, cavity, linac	1424
	S. Ahmadiannamin ILSF, Tehran, Iran F. Abbasi, F. Ghasemi Shahid Beheshti University, Tehran, Iran M. Lamehi, M. Shirshekan IPM, Tehran, Iran
	Constant impedance accelerator RF cavities are constructed from similar resonator cells that stacked to each other. Best operation condition is achieved when all of cells resonate in one resonance frequency with similar quality factors. So, measurement and tuning of RF cavities is the critical step for final best operation of linear accelerators. In this paper, the electromagnetic computer simulations, RF measurement and final tuning of a nine cell periodic accelerator structure was represented. All of cavities tuned in one resonant frequency and according to theoretical concepts we obtain nine resonant modes from RF measurements by vector network analyzer.
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TUPAB056	New Achievements of the Laser System for RF-Gun at SuperKEKB Injector	laser, gun, electron, experiment	1452
	R. Zhang, T. Natsui, Y. Ogawa, M. Yoshida, X. Zhou KEK, Ibaraki, Japan
	For realizing high charge and low emittance electron and positron beams in SuperKEKB, we have been making improvements in current laser system for RF-gun. In order to realize more excellent thermal management in current laser system at high repetition rate operation, novel soldering Yb:YAG thin disk and copper tungsten heat sink laser head is manufactured via gold tin solder. Comparing with old design, less residual stress is introduced and more efficient thermal removal can be obtained. These new soldering laser heads are placed into a compact vacuum chamber and cooled by Peltier plates directly. This design can realize higher gain and amplification factor in regenerative amplifier and multi-pass amplifier. In addition, the compact and simple cooling method can achieve excellent thermal management for the purpose of realize laser operation at high repetition rate for following phases of SuperKEKB project. A perspective towards the next step experiment is also presented in this paper.
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TUPAB095	The New MAX IV Gun Test Stand	gun, laser, emittance, cathode	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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TUPAB103	Orbit Correction With Path Length Compensation Based on Rf Frequency Adjusments in TPS	electron, feedback, site, photon	1553
	P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Huang, C.-C. Kuo, C.C. Liang, Y.-C. Liu, H.-J. Tsai, F.H. Tseng NSRRC, Hsinchu, Taiwan
	The 3 GeV Taiwan Photon Source has been routinely operated for public users since September 2016. Orbit reproducibility and stability are critical for the quality of user experiments. Ambient temperature variations and earth tides can cause a change in circumference, changing in turn the beam energy, and orbit drift. Therefore both, orbit correction and rf frequency adjustments are necessary to keep the ring circumference constant. A Fast Orbit Feedback (FOFB) system combined with rf frequency correction deduced from the fast corrector strengths is applied to the FOFB routine. The correlation between the measured frequency variation with ambient temperature and earth tides is also reported in this article.
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TUPAB108	Upgrade of BTS Control System for the Taiwan Light Source	controls, EPICS, interface, GUI	1570
	Y.-S. Cheng, J. Chen, K.T. Hsu, K.H. Hu, C.H. Huang, D. Lee, C.Y. Liao, C.Y. Wu NSRRC, Hsinchu, Taiwan
	The Taiwan Light Source (TLS) is a third generation of synchrotron light source, and it has been operated since 1993. The TLS control system is a proprietary design. It was performed minor upgrade several times to avoid obsolete of some system components and keep up-to-date during last two decades. The control system of BTS (Booster-to-Storage ring) transport line includes control interfaces of power supplies, screen monitors, vacuum and temperature. The cPCI (CompactPCI) based EPICS IOC (Input Output Controller) has been adopted for renewing TLS BTS control system to replace the existed VME based ILC (Intelligent Local Controller) to be as an easy-to-maintain control environment. Moreover, each TLS control console supports not only the existing control software interfaces, but also the newly developed EPICS graphical user interfaces. Upgraded TLS BTS control system had been successfully commissioning in February 2017. Compare new system with old system, new system provides more functionality, fast response, and highly reliability. The efforts are summarized at this paper.
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TUPAB109	Study on Injection with Pulsed Multipole Magnet for SPS Storage Ring	injection, multipole, kicker, storage-ring	1573
	T. Pulampong, P. Klysubun, P. Sudmuang, P. Sunwong SLRI, Nakhon Ratchasima, Thailand
	Pulsed multipole magnet (PM) has zero magnetic field at the centre, therefore it introduces no perturbation to the stored beam. It has been demonstrated that this injection scheme is able to minimise the oscillation of the stored beam, and thus make it suitable for top-up operation. To investigate the suitability of employing this injection method at Siam Photon Source, PM was modelled and optimised for best performance using particle tracking based method. This work presents injection optimisation process with PM considering various constraints such as position of injected beam, injection conditions, and effects of installed IDs.
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TUPAB130	Status of the LCLS-II Superconducting RF Linac	cryomodule, cavity, linac, FEL	1630
	A. Burrill SLAC, Menlo Park, California, USA
	The LCLS-II project requires the assembly and installation of 37 cryomodules in order to deliver a 4 GeV electron beam to the undulators to produce both soft and hard x-ray pulses at a repetition rate up to 1 MHz. All of the cryomodules will operate in continuous wave mode, with 35 operating at 1.3 GHz for acceleration and 2 operating at 3.9 GHz to linearize the longitudinal beam profile. The assembly and testing of the 1.3 GHz cryomodules is well underway and the 3.9 GHz cryomodule work is entering into the pre-cryomodule testing and component validation phase. Both of these efforts will be reported on in this paper.
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TUPAB132	A Novel Dual-Mode Dual-Frequency Linac Design	impedance, cavity, network, distributed	1634

Paper

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MOXAA1

Commissioning of the European XFEL Accelerator

linac, electron, undulator, emittance

1

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

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

Slides MOXAA1 [22.967 MB]

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MOYAA1

Approaching the Nominal Performance at the LHC

luminosity, emittance, 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, simulation, emittance, 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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MOOCA3

Amorphous Carbon Thin Film Coating of the SPS Beamline: Evaluation of the First Coating Implementation

vacuum, electron, cathode, proton

44

M. Van Gompel, P. Chiggiato, P. Costa Pinto, P. Cruikshank, C. Pasquino, J. Perez Espinos, A. Sapountzis, M. Taborelli, W. Vollenberg
CERN, Geneva, Switzerland

As part of the LHC Injector Upgrade (LIU) project, the Super Proton Synchrotron (SPS) must be upgraded in order to inject in the LHC 25 ns bunch spaced beams of higher intensity. To mitigate the Electron Multipacting (EM) phenomenon in the SPS, CERN developed thin film carbon coatings with a low Secondary Electron Yield (SEY). The development went from coating small samples, up to coating of 6 m long vacuum chambers directly installed in the magnets. To deposit the low SEY amorphous carbon (aC) film on the vacuum chamber inner wall of SPS ring components, a modular hollow cathode train was designed. The minimization of the logistical impact requires a strategy combining in-situ and ex-situ coating, depending on the type of components. To validate the implementation strategy of the aC thin films and the in-situ coating process along the 7 km long SPS beamline, approximately 2 cells of B-type bending dipoles and 9 focussing quadrupoles are foreseen to be treated with the aC coating during the Extended Year End Technical Stop (EYETS) 2016-2017. We will discuss the coating technique and evaluate both the implementation process and the resulting coating performance.

Slides MOOCA3 [71.421 MB]

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MOOCB2

Laser System Design and Operation for SNS H⁻ Beam Laser Stripping

laser, experiment, ion, neutron

57

Y. Liu, A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, A.A. Menshov, A. Webster
ORNL, Oak Ridge, Tennessee, USA
A. Rakhman
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This work has been partially supported by U.S. DOE grant DE-FG02-13ER41967. ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
Recently, a high-efficiency laser assisted hydrogen ion (H⁻) beam stripping was successfully carried out in the Spallation Neutron Source (SNS) accelerator. The experiment was not only an important step toward foil-less H⁻ stripping for charge exchange injection, it also served as a first example of using megawatt ultraviolet (UV) laser in an operational high power proton accelerator facility. This talk reports the design, implementation, and commissioning results of the macropulse laser system, laser transport line, and laser operation for the laser stripping experiment. The macropulse laser consists of a mode-locked picosecond pulsed seed laser and a burst-mode Nd:YAG laser amplifier. The general design concept can be adapted to any temporal beam structures in most accelerators. We have achieved UV pulses with the pulse widths varying between 34 to 54 ps and a maximum peak power over 3.5 MW. A laser transport line is installed to deliver the UV beam to the laser stripping chamber at a transmission efficiency of 70%. Laser operation including remote control and monitor of laser parameters will be described.

Slides MOOCB2 [11.306 MB]

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MOPAB004

Improved Protection of the Warm Magnets of the LHC Betatron Cleaning Insertion

shielding, radiation, luminosity, collimation

72

C. Bahamonde Castro, F. Cerutti, P. Fessia, A. Lechner, A. Mereghetti, D. Mirarchi, S. Redaelli, E. Skordis
CERN, Geneva, Switzerland
E. Skordis
The University of Liverpool, Liverpool, United Kingdom

After the High Luminosity (HL) upgrade in 2024-2026, the LHC is anticipated to increase its integrated luminosity by a factor of 10 beyond its original design value of 300 fb-1. In preparation for this, several improvements to the equipment will already be implemented during the next Long Shutdown (LS2) starting in 2019. In the betatron cleaning insertion, the debris leaking out of several collimators will deposit energy in the downstream warm magnets, causing long-term radiation damage. A new layout has been proposed in which the most exposed magnet of each assembly is removed, reducing the assembly from 6 to 5 magnet units and gaining 2 spare magnets. New absorbers are therefore required to enhance the shielding of the remaining magnet string. In this paper, we present an evaluation of the dose to the warm magnets for post-LS2 operation, and we quantify the achievable reduction of the long-term radiation damage for different absorber configurations. A solution for an improved magnet protection that fulfills the HL-LHC requirements is proposed.

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MOPAB032

Status of a Double Slit Interferometer for Transverse Beam Size Measurements at BESSY II

diagnostics, storage-ring, synchrotron, radiation

149

M. Koopmans, P. Goslawski, J.G. Hwang, M. Ries, M. Ruprecht, A. Schälicke
HZB, Berlin, Germany

Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of Helmholtz Association
The upgrade of the BESSY II storage ring to BESSY VSR* demands additional beam diagnostics for machine commissioning and development. Especially bunch resolved measurements are needed. Currently, transverse beam size measurements are done with X-ray pinhole monitor systems, which cannot provide bunch resolved information. Alternative methods to measure the transverse beam size using synchrotron radiation in the visible spectrum are interferometric techniques, which could also be upgraded to bunch resolved systems. For that purpose a double slit interferometer has been constructed. Commissioning of the system has started and experimental results are discussed and compared with the existing pinhole system.
* A. Jankowiak et al., eds., ''BESSY VSR - Technical Design Study'', Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany, June 2015.

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MOPAB039

Development of a Control System Based on Experimental Data for Space Charge Lenses

electron, plasma, ion, space-charge

166

S. Klaproth, C. Beberweil, M. Droba, O. Meusel, H. Podlech, B.E.J. Scheible, K. Schulte, K.I. Thoma, C. Wagner
IAP, Frankfurt am Main, Germany

Space charge lenses use a confined electron cloud for the focusing of ion beams. The electron density gives the focusing strength whereas the density distribution influences the mapping quality of the space charge lens and is related to the confinement. The major role of the electron density with respect to the focusing quality has been pointed out many times in the past *,**. With an automated measurement system the radial light density profile, plasma stability and mean value of the electron density have been measured in respect to the confining fields and the pressure. The results are summarized in 3D-maps. The theoretical model approximations for space charge lenses predicts high electron densities then measured. With the automated system the realistic 3D-maps can be considered instead of an approximation of a theoretical density including knowledge of the most stable electron cloud achievable within the parameter range of the lens. The experimental results of the automated measurement system will be presented here and a concept of a control system for this type of space charge lenses will be explained.
* O. Meusel, 'Focussing and transport of ion beams using space charge lenses', PhD thesis, 2006

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MOPAB040

Linear and Nonlinear Optics Measurements With Multiturn Data at PETRA III

optics, kicker, diagnostics, injection

170

I.V. Agapov, M. Bieler, H. Ehrlichmann, J. Keil, J. Klute, G. Kube, G.K. Sahoo, F. Schmidt-Föhre, R. Wanzenberg
DESY, Hamburg, Germany
R. Tomás, A. Wegscheider
CERN, Geneva, Switzerland

At Petra III measuring multiturn beam response to pulsed and continuous excitations allows linear and nonlinear (e.g. frequency maps) optics parameter determination. We describe the measurement setup, approaches to optics parameter determination, and the measurement results for Petra III.

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MOPAB042

Two-Dimensional Synchrotron Radiation Interferometry at PETRA III

synchrotron, radiation, emittance, synchrotron-radiation

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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MOPAB043

Very First Experience with the Standard Diagnostics at the European XFEL

diagnostics, electron, cavity, electronics

180

D. Lipka
DESY, Hamburg, Germany

The whole European XFEL becomes in operation this year. Dedicated standard diagnostics systems are installed and almost all types are tested at the injector before. Now the standard diagnostics are used to commission the facility. In this contribution the very first results and the operation experiences of the standard beam diagnostics of the entire European XFEL are reported.

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MOPAB070

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

injection, linac, proton, synchrotron

277

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

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

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MOPAB071

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

diagnostics, linac, pick-up, impedance

281

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

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

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MOPAB084

Online Measurement of Electrode Gains for Stripline Beam Position Monitor in the HLS II Storage Ring

storage-ring, quadrupole, site, radiation

316

F.F. Wu, L. Lin, X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, J.G. Wang, J.H. Wei, Y.L. Yang, T.Y. Zhou, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Supported by the National Key Research and Development Program of China(No. 2016YFA0402000) and the National Science Foundation of China (11575181, 11605202)
Three axially symmetric stripline beam position monitors were installed in the HLS II storage ring and each stripline BPM was machined with button BPM together. Due to mechanical errors of stripline BPM, differences in electrode gains will lead to measurement error for beam position and mutual coupling between beam horizontal position and vertical position. So it is very important to calibrate electrode gains for axially symmetric BPM. A method was proposed to calibrate electrode gains of this kind of BPM. This method is suitable for all axially symmetric BPMs, whether stripline BPM or button BPM. The online calibrated gains were compared with offline calibrated gains and the results have shown that online and offline calibrated electrode gains were basically consistent.

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MOPAB096

Universal Digital Aggregator for in-Line Signal Processing

hardware, software, target, PLC

352

M.P. Kopeć, L.J. Dudek, A. Kisiel, M.A. Knafel, A.I. Wawrzyniak, M. Zając
Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland

Universal digital aggregator is a device for general signal processing with around 100kHz bandwidth. It contains of 4 inputs and 4 open-drain outputs - all of which are fully programmable. When the number of controlling digital signals exceeds the number of input ports of a device there is a need to either multiplex those signals or process them before the target device. The aggregator can be powered from the target device so no additional cabling is needed, especially considering its low power consumption. This straightforward, complex and portable device can be easily applied where PLC solutions are difficult to implement.

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MOPAB100

The Development of Button Type BPM Electronics for RAON

electronics, pick-up, ion, FPGA

362

S.W. Jang, E.-S. Kim, Y. Lee
Korea University Sejong Campus, Sejong, Republic of Korea
Y.S. Chung, G.D. Kim, H.J. Woo
IBS, Daejeon, Republic of Korea
J.W. Kwon
Korea University, Seoul, Republic of Korea

RAON is a heavy ion accelerator for the Rare Isotope Science Project in Korea. The main goals of RAON is to accelerate various stable ions from ECR ion source and rare isotopes ions from ISOL beam line. For the stable beam operation, the beam diagnostics equipment is very important. Recently, we developed a digital board electronics for the button type beam position monitor (BPM) to measure the position of ion beams. In this presentation, design of electronics, beam signal simulation results, and RF measurement test results with a developed button BPM will be described.

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MOPAB109

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

emittance, luminosity, 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

emittance, luminosity, experiment, detector

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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MOPAB113

Usage of the Transverse Damper Observation Box for High Sampling Rate Transverse Position Data in the LHC

injection, diagnostics, impedance, pick-up

389

L.R. Carver, X. Buffat, A.C. Butterworth, W. Höfle, G. Iadarola, G. Kotzian, K.S.B. Li, E. Métral, M. Ojeda Sandonís, M.E. Söderén, D. Valuch
CERN, Geneva, Switzerland

The transverse damper observation box (ADTObsBox) is a device that makes accessible the bunch-by-bunch turn-by-turn data recorded from the pickups of the LHC transverse damper. This device can provide online transient analysis of different beam dynamics effects (tunes and damping times at injection, for example), while also under development is an online coherent instability triggering system. This paper will provide an overview of the current setup and plans for future upgrades, as well as detailing how it deals with the large volume of data being generated. The results of some analysis that rely on the ADTObsBox will also be shown.

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MOPAB117

Online Bunch by Bunch Transverse Instability Detection in LHC

pick-up, network, feedback, injection

397

M.E. Söderén, G. Kotzian, M. Ojeda Sandonís, D. Valuch
CERN, Geneva, Switzerland

Reliable detection of developing transverse instabilities in the Large Hadron Collider is one of the main operational challenges of the LHC's high intensity proton run. A full machine snapshot provided from the moment of instability is a crucial input to develop and fine tune instability models. The transverse feedback system (ADT) is the only instrument in LHC, where a full rate bunch by bunch transverse position information is available. Together with a sub-micron resolution it makes it a perfect place to detect transverse beam motion. Very large amounts of data, at very high data rates (8 Gb/s) need to be processed on the fly to detect onset of transverse instability. A very powerful computer system (so called ADTObsBox) was developed and put into operation by the CERN RF group, which is capable of processing the full rate data streams from ADT and perform an on the fly instability detection. The output of this system is a timing event with a list of all bunches developing instability, which is then sent to the LHC-wide instability trigger network to freeze other observation instruments. The device also provides buffers with raw position data for offline analysis.

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MOPAB122

Fast Bunch by Bunch Tune Measurements at the CERN PS

injection, betatron, proton, synchrotron

415

P. Zisopoulos, M. Gąsior, M. Serluca, G. Sterbini
CERN, Geneva, Switzerland

The CERN Proton Synchrotron (PS) is a crucial component of the Large Hadron Collider (LHC) injector complex. The PS role is to provide beams of high brightness and with the required time structure. In this paper, we present the results of bunch-by-bunch tune measurements by using turn-by-turn transverse beam position monitors (BPMs). The data from different BPMs are combined together to allow fast and accurate tune measurements for each bunch. The obtained results are compared with the present PS tune-meter system and the specific advantages and limits of this technique are commented and exemplified.

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MOPAB124

A Fast Gain Calibration Algorithm for Beam Position Monitoring at Taiwan Photon Source

pick-up, storage-ring, electron, target

419

J.Y. Chen, C.H. Chen, M.-S. Chiu, P.C. Chiu, P.J. Chou, S. Fann, K.H. Hu, C.S. Huang, C.-C. Kuo, T.Y. Lee, C.C. Liang, Y.-C. Liu, G.-H. Luo, H.-J. Tsai, F.H. Tseng
NSRRC, Hsinchu, Taiwan

A stable, reliable and well-calibrated beam position monitor (BPM) system is essential for the operation of accelerators. At newly constructed Taiwan Photon Source (TPS), it not only helps us to determine the accelerator parameters, such as Twiss parameters and tune, but also to avoid the damage on accelerator instruments caused by high-energy particle beams or radiation. In this study, we demonstrate a new BPM calibration scheme at TPS storage ring. To excite the electron beams inside accelerator beam pipe by one horizontal or vertical corrector magnet, we measure the response of analog-to-digital converter (ADC) of each BPM pick-up electrodes with different lateral positions and beam currents. Depending on the measured ADC responses, we calibrated the beam position monitor system. Simultaneously, because of limited preparation time after every long shutdown, we are looking for a fast algorithm to ensure the measurement could be done easily and finished as quickly as possible.

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MOPAB125

Post-Mortem System for the Taiwan Photon Source

kicker, timing, photon, data-acquisition

422

C.Y. Liao, Y.-S. Cheng, K.T. Hsu, K.H. Hu, C.H. Huang, C.Y. Wu
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS), a 3-GeV third-generation synchrotron light source located in Hsinchu, is available to users since 2016. During operation, it will inevitably encounter system trips caused by beam losses. Thus, a post-mortem (PM) system is an important tool to analyze the cause of such events. Main functions of the PM system are: (i) PM trigger will be generated when the stored beam is suddenly lost abnormally; (ii) storage of relevant signals when the server receives such a trigger; (iii) PM Viewer to analyze each event and understand the cause and effect of a beam trip event. The post-mortem system architecture, plans and implementation will be discussed in this report.

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MOPAB131

Transverse Emittance Measurements Using LHCb's Beam-Gas Interactions

detector, emittance, real-time, experiment

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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MOPAB151

Techniques for Transparent Lattice Measurement and Correction

lattice, feedback, betatron, storage-ring

483

W.X. Cheng, K. Ha, Y. Li
BNL, Upton, Long Island, New York, USA

Funding: Work supported by DOE contract No: DE-SC0012704
NSLS-II storage ring started top off operation since Oct 2015. It has been noticed during the user operation that machine lattice was affected by insertion devices (ID). The storage ring coupling, emittance and lifetime vary when ID gap changes. Lattice characterization was typically carried out with dedicated machine study time with low storage current. Due to collective effect, the lattice at high operation current is different. To characterize the machine lattice during normal user operation with little disturbance, a small portion of beam (~1%) filled in the ion gap can be excited by the bunch by bunch feedback system near betatron frequency. Recent development on BPM electronics enables the gate function to detect partial beam motion in the ring. With the gated BPM turn by turn data from excited bunches, storage ring lattice can be measured and corrected with the well-developed tools. We present in the paper preliminary test results with these tools to characterize the lattice and how it improves the machine performance during user operation.

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MOPIK004

Demonstration of an All-Optically Driven Sub-keV THz Gun

electron, gun, acceleration, laser

503

W.R. Huang, K.-H. Hong, F.X. Kärtner, E.A. Nanni, KR. Ravi
MIT, Cambridge, Massachusetts, USA
A-L. Calendron, H. Cankaya, A. Fallahi, F.X. Kärtner, X. Wu
CFEL, Hamburg, Germany
D. Zhang
DESY, Hamburg, Germany

Funding: European Research Council under the European Union Seventh Framework Program (FP/2007-2013)/ERC Grant Agreement no. 609920
Intense ultrashort THz and optical pulses with single-cycle pulse duration became possible after the recent advances in ultrafast technologies. Using such ultrashort pulses for electron acceleration offers advantages in terms of higher thresholds for material breakdown which opens up a promising path towards increased acceleration gradients. In addition, using optically generated THz pulses enable inherently synchronized acceleration schemes, since accelerating field and particle injecting field are excited by a single seed laser. In this contribution, we present the first experimental demonstration of laser-driven THz acceleration of electrons initially at rest. It is shown that strong-field, single-cycle THz fields accelerate electrons with peak energies of up to 0.8 keV in an ultracompact THz gun with bunch charge of 40 fC. The achieved energy spreads are as low as 5.8%.

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MOPIK026

Commissioning and Operation of an Ultrafast Electron Diffraction Facility as Part of the ATF-II Upgrade at Brookhaven National Laboratory

electron, laser, photon, experiment

554

M.G. Fedurin, M. Babzien, C. Folz, M. Fulkerson, K. Kusche, J.J. Li, R. Malone, M.A. Palmer, T.V. Shaftan, J. Skaritka, L. Snydstrup, C. Swinson, F.J. Willeke
BNL, Upton, Long Island, New York, USA

Funding: Work supported by the US DOE under contract DE-SC0012704.
The Accelerator Test Facility (ATF) at Brookhaven National Laboratory (BNL) is presently carrying out an upgrade, ATF-II, which will provide significantly expanded experimental space and capabilities for its users. One of the new capabilities being integrated into the ATF-II program is an Ultrafast Electron Diffraction (UED) beam line, which was originally deployed in the BNL Source Development Laboratory. Inclusion of the UED in the ATF-II research portfolio will enable ongoing development and extension of the UED capabilities for use in materials research. We describe the design, operation and future plans for the UED beam line at the ATF-II.

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MOPIK032

Commissioning of the AISHa Ion Source at INFN-LNS

ion, ion-source, plasma, injection

570

L. Celona, G. Castro, F. Chines, G. Costa, S. Gammino, O. Leonardi, S. Marletta, D. Mascali, A. Maugeri, L. Neri, F. Noto, S. Passarello, G. Pastore, A. Seminara, G. Torrisi, S. Vinciguerra
INFN/LNS, Catania, Italy
S. Di Martino, P. Nicotra
Si.A.Tel SRL, Catania, Italy

At INFN-LNS the commissioning of the AISHa superconducting ECRIS started in November 2016. Highly charged ion beams with low ripple, high stability and high reproducibility are the most important features for the ongoing commissioning. In this work, we will show the preliminary results of a parametric study on the extracted current/beam in order to minimize the emittance and increase the brightness taking advantage by its hybrid magnetic system and by a fine frequency tuning system.

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MOPIK033

The Development of a New Low Field Septum Magnet System for Fast Extraction in Main Ring of J-PARC

septum, feedback, extraction, power-supply

573

T. Shibata, K. Ishii, H. Matsumoto, N. Matsumoto, T. Sugimoto
KEK, Ibaraki, Japan
K.J. Kuanjun
HUST, Wuhan, People's Republic of China

The J-PARC Main Ring (MR) is being upgraded to improve its beam power to the design goal of 750 kW. One important way is to reduce the repetition period from 2.48 s to 1.3 s so that the beam power can be nearly doubled. We need to improve the septum magnets for fast extraction. We are improving the magnets and their power supplies. The present magnets which is conventional type have problem in durability of septum coil by its vibration, and large leakage field. The new magnets are eddy current type. The eddy current type does not have septum coil, but has a thin plate. We expect that there is no problem in durability, we can construct the thin septum plate, the leakage field can be reduced. The output of the present power supply are pattern current which of flat top is 10 ms width, the new one is short pulse which of one is 10 us. The short pulse consists of 1st and 3rd higher harmonic. We can expect that the flatness and reproducibility of flat top current can be improved. The calorific power can be also reduced. This paper will report the field measurement results with the eddy septum magnet systems.

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MOPIK034

The New High Field Injection Septum Magnet System for Main Ring of J-PARC

septum, injection, power-supply, flattop

576

T. Shibata, K. Ishii, H. Matsumoto, N. Matsumoto, T. Sugimoto
KEK, Ibaraki, Japan
K. Fan
HUST, Wuhan, People's Republic of China

We are improving the Main Ring (MR) for beam power of 750 kw which is the first goal of J-PARC. The repetition period of the fast extraction must be short to 1.3 second from the current period of 2.48 second for the improvement of the beam power. We exchanged a injection septum magnet which are located at the injection line from RCS to MR and its power supply in summer of 2016. It was necessary to exchange, because the previous injection septum system can not be operated with 1.3 second repetition. The development of the new injection septum magnet and its power supply in which the maximum repetition are 1Hz and the order od the leakage field are 10^-4 of the gap field were completed in 2016. In this presentation, we will report the final results of its performance, e.g. the magnetic fields and stability of the output current and field, and the beam performance after installation in MR with the new injection magnet.

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MOPIK035

New Injection Scheme of J-PARC Rapid Cycling Synchrotron

injection, proton, synchrotron, shielding

579

K. Yamamoto, H. Harada, H. Hotchi, J. Kamiya, P.K. Saha, T. Takayanagi, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
N. Miki, O. Takeda
Nippon Advanced Technology Co., Ltd., Tokai, Japan

The 3-GeV Rapid Cycling Synchrotron (RCS) of Japan Proton Accelerator Research Complex (J-PARC) aims to deliver 1-MW proton beam to the neutron target and Main Ring synchrotron (MR). Present beam power of RCS is up to 500-kW and the higher radiation doses were concentrated in the injection area. These activations were caused by the interaction between the foil and the beam. To reduce the worker dose near the injection point, we have studied new design of the injection scheme to secure enough space for radiation shielding and bellows. In the new system, two of four injection pulse bump magnets are replaced and we are able to ensure the additional 500 mm space at the injection foil .

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MOPIK038

Initial Operation of the Low-Flux Proton Beamline at the KOMAC 100 MeV Linac

proton, target, octupole, vacuum

585

S.P. Yun, C.R. Kim, D.I. Kim, H.S. Kim, H.-J. Kwon, S.G. Lee, Y.G. Song
Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea

Funding: This work was supported by the Ministry of Science, ICT and Future Planning of the Korean Government
Korea multi-purpose Accelerator Complex (KOMAC) has been operating 20 MeV and 100 MeV proton beamlines to provide proton beams to users since 2013. The new beamline and target irradiation facility, which is proposed applicable to development of the detector and simulation of the space radiation, have being constructed for low-flux proton utilization at this year. The new beam lines have the 100 MeV of maximum beam energy and 10 nA of maximum beam current. The new beam line was designed to operate with maximum duty 8%, the flux density of proton beam can be reduced to the 1/10,000 by the graphite collimator. The extracted proton beam energy can be adjustable by the double wedge type energy degrader and also, the beam energy can be selected by dipole magnet. In addition to the two sets of the octupole magnets were prepared for uniform beam irradiation with the ± 5% uniformity. In this paper, the initial operation results of the constructed new beam line is be described.

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MOPIK047

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

injection, linac, proton, vacuum

619

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

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

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MOPIK065

Status of the Development of a BE-Model-Based Program for Orbit Correction at the Electron Storage Ring DELTA

storage-ring, closed-orbit, hardware, synchrotron

673

S. Koetter, B. Riemann, T. Weis
DELTA, Dortmund, Germany

A new program for orbit correction is currently being developed at the electron storage ring DELTA. Based upon the standard approach of utilizing the linear response of a closed orbit to dipole-field-strength variations, proposed features include a live-updated orbit-response-matrix model and the integration of the Closed-Orbit-Bilinear-Exponential-Analysis algorithm (COBEA) to clean measured orbit-response matrices from noise. This work focuses on the current status of development of the aforementioned program. After an assessment of the situation at DELTA, first measurements are shown along with numerical convergence studies.

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MOPIK085

Linear Optics Calibration at the HLS-II Storage Ring Using Model Independent Analysis

storage-ring, optics, lattice, experiment

727

G. Liu, L. Wang, F.F. Wu, K. Xuan
USTC/NSRL, Hefei, Anhui, People's Republic of China

Linear optics are the main lattice parameters characterizing the linear properties of storage rings. Especially for beta function and phase advance, they are the basic lattice functions which must be accurately calibrated to ensure high quality operation of the machine. Model Independent Analysis (MIA), which adopts mathematical statistical methods to extract the effective lattice information of storage rings by directly analyzing the turn-by-turn beam-position-monitor (BPM) measurements, has been applied at HLS-II to calibrate the linear optics model of the storage ring. The measurements of the turn-by-turn BPM data with all of the 32 BPMs are reported in this paper. The calibration results of the beta function using MIA are presented.

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MOPIK098

Techniques for Achieving High Reliability Operation of the Spallation Neutron Source High Power Radio-Frequency System

klystron, cathode, cavity, neutron

756

J. Moss, M.S. Champion
ORNL, Oak Ridge, Tennessee, USA

Funding: *ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This research was supported by the DOE Office of Science, Basic Energy Science, Scientific User Facilities.
The Spallation Neutron Source (SNS) high power radiofrequency (HPRF) system operates with high reliability to support the goals of the SNS user program. In recent operational periods the availability of the HPRF System has exceeded 97 percent while the neutron source availability overall is typically greater than 90 percent. SNS has a unique set of 92 HPRF stations that operate at either 402.5 MHz or 805 MHz with peak output power ranging from 550 kW to 5 MW and average power ranging from 49.5 kW to 450 kW. The HPRF transmitters consist of chassis-mounted power supplies, solid-state amplifiers and other equipment that support the operation of the klystrons that ultimately provide the RF power to the accelerating structures. Management of the operation and maintenance of the HPRF system has increasingly focused on reliability and sustainability in recent years. Techniques for klystron lifetime preservation and optimization of transmitter reliability have been developed and will be described.

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MOPIK102

Beam Dynamics Studies of the HIE-ISOLDE Transfer Lines in the Presence of Magnetic Stray Fields

quadrupole, experiment, shielding, solenoid

768

J. Mertens, J. Bauche, M.A. Fraser, B. Goddard, R. Ostojić, J.S. Schmidt
CERN, Geneva, Switzerland

The ISOLDE facility at CERN produces radioactive isotopes far from stability for fundamental nuclear physics research. The radioactive beams are accelerated to high-energy using a post-accelerator before being transferred for study in different experiments at the end of a network of High Energy Beam Transfer (HEBT) lines. In the framework of the HIE-ISOLDE project, the energy of post-accelerated beams is to be increased to over 10 MeV/u and new experimental detectors are being proposed for installation to exploit the new energy regime. The stray magnetic fields associated with many of the new detectors will distort the beam trajectories in the HEBT, potentially affecting the transmission of the low intensity beams delivered to the experiments. In this contribution, the influence on the HEBT of the stray field of the proposed ISOL Solenoidal Spectrometer is discussed, correction schemes described and shielding options assessed.

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MOPIK103

Operation with Carbon Stripping Foils at ISIS

injection, electron, synchrotron, emittance

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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MOPIK126

Establishing a Project Management Office for the Large Scale Multi Project FAIR

project-management, site, controls, interface

835

F. Becker, S. Deveaux, A. Fröhlich, G. Hickler, M. Lautenschläger, M. Raponi, B. Schoenfelder, M. Strangmann, N. Winters
GSI, Darmstadt, Germany
J.R. Regler, D. Urner
FAIR, Darmstadt, Germany

The Facility for Antiproton and Ion Research (FAIR) is a large scale multi project comprising 10 subprojects in the field of accelerators (pLINAC, SIS100, SuperFRS, p-bar Separator, Collector Ring, High Energy Storage Ring), experiments (CBM, APPA, NUSTAR, PANDA) and civil construction. This contribution describes an integrated approach how a controlling type project management office (PMO) was established, meeting the overall requirements for project steering and specific requirements of the subprojects and international partners involved. Major responsibilities of the PMO are project planning, integrated reporting, cost and budget control, risk management, in-kind coordination & procurement, quality assurance & configuration management. Core processes, roles and responsibilities, methodology and interfaces internally and towards the project pillars are presented.

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MOPVA013

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

linac, electron, acceleration, recirculation

873

F. Hug
IKP, Mainz, Germany

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

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MOPVA014

Injector Linac Stability Requirements for High Precision Experiments at MESA

experiment, linac, electron, acceleration

876

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

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

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MOPVA019

60 pC Bunch Charge Operation of the Compact ERL at KEK

emittance, 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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MOPVA021

Optics Design of the Compact ERL Injector for 60 pC Bunch Charge Operation

optics, cathode, laser, gun

898

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

EUV-FEL light source based on ERL has been designed at KEK for EUV lithography light source. The advantage of ERL is to accelerate high average current beam due to CW operation, and it is possible to drive high average power FEL. To generate the target EUV-FEL power, which is 10 kW, the bunch charge of 60 pC, the beam energy of 10.5 MeV and the bunch length of 1 ps are required at the end of the EUV-FEL injector. In order to demonstrate the target beam performance for the EUV-FEL accelerator, a high charge beam test was carried out at the cERL in KEK. We designed a new optics of the cERL injector prior to the high charge beam operation. To calculate beam dynamics more accurately, accelerator models corrected according to the condition of the actual cERL injector is used for the optics design. From results of the optics design that minimized the emittance and bunch length using the corrected accelerator models, the emittance and bunch length at the end of injector are 0.8 mm-mrad and 3.4 ps. Furthermore, based on the design optics, we carried out high bunch charge beam operation.

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MOPVA039

Manufacturing and Validation Tests of IFMIF Low-Beta HWRs

cavity, cryomodule, SRF, simulation

942

G. Devanz, F. Éozénou, L. Maurice, P. Sahuquet, C. Servouin
CEA/DSM/IRFU, France
N. Bazin, P. Carbonnier, P. Charon, G. Disset, P. Hardy, E. Jacques, O. Piquet, D. Roudier
CEA/IRFU, Gif-sur-Yvette, France
J.K. Chambrillon, T. Percerou
CEA/DRF/IRFU, Gif-sur-Yvette, France

The IFMIF accelerator aims to provide an accelerator-based D-Li neutron source to produce high intensity high energy neutron flux to test samples as possible candidate materials to a full lifetime of fusion energy reactors. A prototype of the low energy part of the accelerator is under construction at Rokkasho in Japan. It includes one cryomodule containing 8 half-wave resonators (HWR) operating at 175 MHz .The first manufactured HWR has passed low power tests at 4.2K in vertical cryostat succesfully and exceeds the specifications. It has also been tested in the dedicated horizontal Sathori cryostat equiped with its cold tuning system. The serial production and qualification tests of the 8 cavities which will eventually equip the cryomodule are carried out in parallel. In this paper, we focus on the HWR preparation and test results and give a status of the manufacturing activities.

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MOPVA048

Simulation of the Thermoelectrically Generated Magnetic Field in a SC Nine-Cell Cavity

cavity, simulation, SRF, superconducting-RF

968

J.M. Köszegi, J. Knobloch, O. Kugeler
HZB, Berlin, Germany

Several studies showed that thermocurrents generate a magnetic field in a horizontal cavity test assembly or cryomodul, which may get trapped during the supercon-ducting phase transition. The trapped flux causes additional dissipation in the order of 1 to 10 n' during operation and can therefore significantly degrade the quality factor in a TESLA cavity. We simulated the distribution of the generated magnetic field over the whole cavity-tank system for an asymmetric temperature distribution. The asymmetry allows the field to penetrate the RF surface which would be field free in the symmetric case. The calculated results complemented a direct measurement of trapped magnetic flux inside the cavity with a small number of field probes. Finally, the obtained data was combined with RF measurements in three passband modes to determine the overall distribution of trapped magnetic flux due to thermocurrents.

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MOPVA051

Design of the High Power 1.5 GHz Input Couplers for BESSY VSR

coupling, cavity, simulation, HOM

978

E. Sharples, M. Dirsat, J. Knobloch, A.V. Vélez
HZB, Berlin, Germany

The Variable pulse length Storage Ring (BESSY VSR) upgrade to BESSY II at Helmholtz-Zentrum Berlin (HZB) requires an upgrade on the RF systems in the form of high-voltage longitudinally focusing super conducting RF cavities of 1.5 GHz ad 1.75 GHz. For operation, coaxial RF power couplers capable of handling 13 kW peak power at standing wave operation are required for both the 1.5 GHz and 1.75 GHz cavities. The coupler is based on a design by Cornell University with modifications to suit frequency and coupling requirements. The coupler is intended to provide variable coupling with a range of Qext from 6x10⁶ to 6x10⁷ to allow flexibility to adjust to operating conditions of BESSY VSR. Here we present the RF design of the high-power coaxial coupler for BESSY VSR along with the design of the test stand for conditioning a pair of couplers.

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MOPVA052

Study on HOM Power Levels in the BESSY VSR Module

HOM, cavity, SRF, resonance

982

A.V. Tsakanian, H.-W. Glock, J. Knobloch, A.V. Vélez
HZB, Berlin, Germany

The BESSY VSR upgrade of the BESSY II light source represents a novel approach to simultaneously store of long (ca. 15ps) and short (ca. 1.5ps) bunches in the storage ring with the 'standard' user optics. This challenging goal requires installation of four new SRF cavities (2x1.5GHz and 2x1.75GHz) in a single module to minimize space requirements. These cavities are equipped with strong waveguide and beam tube HOM dampers necessary for stable operation. The expected HOM power and spectrum has been analyzed for the complete module. This study is performed for various BESSY VSR bunch filling patterns with 300 mA beam current. In the module different cavity arrangements are analyzed to reach the optimal operation conditions with equally distributed power portions in warm HOM loads and tolerable beam coupling impedance.

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MOPVA055

Upgrade of the Capture Section of the S-DALINAC Injector

cavity, SRF, electron, accelerating-gradient

993

D.B. Bazyl, H. De Gersem, W.F.O. Müller
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: This work is supported by the DFG through GRK 2128.
In order to reduce the energy spread of the recirculated beam, the injector of the S-DALINAC needs to be optimized, because the non-isochronous recirculation cannot correct for errors originating from the injector linac. For the S-DALINAC, spatial restrictions suggest the use of SRF technology for the capture section. In this work, we consider various SRF cavities with an operating frequency of 3 GHz for a possible upgrade of the capture section of the S-DALINAC. The first results of the RF and beam dynamics simulations for the proposed options are presented in this paper.

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MOPVA058

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

cavity, LLRF, linac, klystron

999

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

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

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MOPVA060

Fabrication and Treatment of the ESS Medium Beta Prototype Cavities

cavity, controls, feedback, vacuum

1003

L. Monaco, A. Bellandi, M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, P. Michelato, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
S. Pirani
ESS, Lund, Sweden

In view of the Medium Beta series cavities production at the industry for the European Spallation Source project, INFN Milano - LASA design prototypes have been fully produced at Ettore Zanon S.p.A. with our supervision. Based on our experience on the production of 1.3 GHz and 3.9 GHz E-XFEL series cavities, we set-up and applied an external quality control activity of the overall production of the prototype cavity, starting from the row materials to the ready to be tested cavity. In this paper, we report the strategy we have adopted on the overall production, mechanical and surface treatments, frequency measurement of subcomponents and cavities and the obtained results.

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MOPVA063

Vertical Tests of ESS Medium Beta Prototype Cavities at LASA

cavity, vacuum, radiation, accelerating-gradient

1015

A. Bosotti, A. Bellandi, M. Bertucci, A. Bignami, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, R. Paparella, P. Pierini, D. Sertore
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
S. Pirani
ESS, Lund, Sweden

In the framework of the INFN activity related to the European Spallation Source collaboration, the LASA infrastructure has been renewed to allow the qualification, in its vertical cryostat, of the 704 MHz medium beta cavity prototypes. A new cryogenic insert has been realized, fully equipped with dedicated mechanical supports, vacuum, thermal sensors and quench diagnostic systems. The RF test station has been upgraded as well with a new PLL electronics rack. The first beta 0.67 cavity prototype designed and produced by INFN Milano has been successfully cold tested at 2.0 K temperature, outperforming the ESS specifications. The technical features of LASA infrastructure, the design of novel components and the experimental results of cavities cold-tests are thoroughly described in this paper.

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MOPVA066

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

cavity, cryomodule, linac, laser

1023

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

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

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MOPVA068

Experience on Design, Fabrication and Testing of a Large Grain ESS Medium Beta Prototype Cavity

cavity, radiation, niobium, cryogenics

1027

D. Sertore, A. Bellandi, M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, R. Paparella, P. Pierini
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
S. Pirani
ESS, Lund, Sweden

We report on the design, fabrication and testing of an ESS Medium Beta prototype cavity made with Large Grain Niobium sheets sliced from an ingot provided by CBMM. The peculiar choices during the fabrication process related to the Large Grain Niobium material are described. We present also the results of the cavity test at cryogenic temperature and the dedicated quench diagnostic.

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MOPVA073

Development of Peak Hold Module for Electron Emission in STF-Type Power Coupler for the ILC

electron, vacuum, cryomodule, monitoring

1034

Y. Yamamoto, E. Kako, T. Shishido
KEK, Ibaraki, Japan

In STF, the RF conditioning for power coupler is done in several steps from 10 to 1650 μs as specified in TDR for the ILC. The most important signals during the RF conditioning are vacuum level, and electron emission by multipacting. The vacuum level changes continuously, and electron emission has pulse-like behavior, which has much faster response. Therefore, it was necessary to develop the peak hold and isolation modules to evaluate electron emission in short pulse width. This module has two kinds of feature. One is pulse height detection, and the other is total charge detection (integrated signal). During the RF conditioning for power couplers in STF-2 cryomodule, this module perfectly worked, and detected different trend between the pulse height and the total charge. In this paper, the detailed result for the peak hold module will be presented.

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MOPVA075

Development of High Sensitive X-Ray Mapping for SC Cavities

cavity, survey, interface, cryogenics

1040

H. Tongu, H. Hokonohara, Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
R.L. Geng, A.D. Palczewski
JLab, Newport News, Virginia, USA
H. Hayano, T. Kubo, T. Saeki, Y. Yamamoto
KEK, Ibaraki, Japan
H. Oikawa
Utsunomiya University, Utsunomiya, Japan

We developed an X-ray mapping system sX-map for superconducting cavities. The sensors are inserted under the stiffener rings between cavity cells, whose locations are close to the iris areas. The whole circuits are im-mersed in liquid He and the multiplexed signals reduces the number of cables to the room temperature region. sX-map has the advantages in its compact size, low cost and simple setup for nondestructive inspections. The sX-map system detected X-rays from field emissions in vertical RF tests of ILC 9-cell cavities at Jefferson Lab (JLab) and KEK. sX-map showed an excellent performance in the meas-urement test at JLab, it exhibited a high sensitivity com-pared with an the fixed diode rings colocated at irises and ion chamber located out side of the vertical test cryostat.

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MOPVA078

The Window Replacement and Q Recovery of BEPCII Storage Ring SCC

cavity, vacuum, positron, radiation

1046

T.M. Huang, J.P. Dai, R. Ge, S.P. Li, Z.Q. Li, H.Y. Lin, Q. Ma, W.M. Pan, Y. Sun, G.W. Wang
IHEP, Beijing, People's Republic of China
P. Sha
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

The storage ring RF system for the upgrade of the Beijing Electron Positron Collider (BEPCII) adopted two 500 MHz superconducting cavities: west for the positron ring (BPR); east for the electron ring (BER). The excessive heating of the west window was observed in Nov.2013, and not cured thoroughly*. After two years operation, the window cracked suddenly on Nov.18th, 2015. The replacement of the window was subsequently implemented in tunnel. However, the quality factor (Q) of the cavity decayed a lot after the window replacement. 90 degrees Celsius N2 gas baking of the outer surface of the cavity was carried out in situ and the Q recovered in a short time. This paper will present the process of the window replacement and the cavity Q recovery in detail.
* Tong-ming Huang et al., Chinese Physics C Vol. 40, No. 6 (2016) 067001

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MOPVA091

Investigation of HOM Frequency Shifts Induced by Mechanical Tolerances

cavity, HOM, simulation, cryogenics

1071

S. Pirani, M. Eshraqi, M. Lindroos
ESS, Lund, Sweden
A. Bosotti, J.F. Chen, P. Michelato, C. Pagani, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
T.P.Å. Åkesson
Lund University, Department of Physics, Lund, Sweden

We present Higher Order Mode (HOM) studies on ESS Medium-Beta cavity of INFN-LASA design, including both simulation and measurement results. Mechanical tolerances of the fabrication process might shift HOMs frequencies toward harmonics of the bunch frequency. Both simulation and measurements at room and cryogenic temperature show that INFN LASA cavity is fully compatible with ESS requirements.

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MOPVA095

First RF Performance Results for the DQW Crab Cavities to be Tested in the CERN SPS

cavity, SRF, monitoring, cryomodule

1077

A. Castilla, R. Calaga, O. Capatina, K.M. Dr. Schirm, K.G. Hernández-Chahín, A. Macpherson, N.C. Shipman, K. Turaj
CERN, Geneva, Switzerland
I. Ben-Zvi
BNL, Upton, Long Island, New York, USA
G. Burt, J.A. Mitchell
Lancaster University, Lancaster, United Kingdom
K.G. Hernández-Chahín
DCI-UG, León, Mexico
N.C. Shipman
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
N.C. Shipman
UMAN, Manchester, United Kingdom

As part of the High Luminosity LHC (HL-LHC) project strategy, crab cavity correctors shall be installed around CMS and ATLAS experiments of the LHC. To accommodate the different crossing angle planes, two distinct cavity designs have been selected: the RF Dipole (RFD) and the Double Quarter Wave resonator (DQW). CERN has fabricated two double quarter wave resonators (DQW_SPS), for validation with a proton beam at the CERN SPS accelerator. Standard superconducting rf surface preparation protocols have been applied to the two bulk niobium cavities, followed by cryogenic testing in a vertical cryostat at CERN's SM18 facility. The performance results obtained after the first bare cavity tests for cavities DQW_SPS₀01 and DQW_SPS₀02 are shown in this paper, and include Q0 vs Vt curves, Lorentz Force Detuning (LFD) analyses and pressure sensitivity of a higher order mode.

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MOPVA098

Strategy Towards Non-Interrupted Operation of Superconducting Radio Frequency Modules at NSRRC

SRF, vacuum, cryogenics, cavity

1088

Ch. Wang, F.Y. Chang, L.-H. Chang, M.H. Chang, J. Chen, L.J. Chen, F.-T. Chung, M.-C. Lin, Z.K. Liu, C.H. Lo, C.L. Tsai, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan

Two modern 3rd generation light sources, the well-developed 1.5-GeV Taiwan Light Source (TLS) and the new constructed 3-GeV Taiwan Photon Source (TPS), are now in routine operation. Both storage rings are powered by the superconducting RF (cavity) modules, one CESR-type SRF module for the TLS since 2005 and two KEKB-type SRF modules for the TPS since 2014. Thanks to continuous efforts, the operational reliability of SRF modules at NSRRC is now compatible or better in comparison with the best operation record of room temperature cavities ever achieved at TLS (1992-2004). How to improve the long term availability but hold the achieved reliability of SRF modules such as to maximize the available annual user beam time, especially, under requirements on high RF power operation, become a new operational challenge, especially for the SRF modules at TPS which is now routinely operated with a forward RF power around 150-kW individually and expected to push to 300-kW in the coming future. Here we report our strategy and achievement to minimize long term interrupt of SRF operation owing to regular full-thermal cycling and annual maintenance of cryogenic plant.

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MOPVA099

The Study of Electromagnet Compensated High Power Ferrite Circulator Operation With Superconducting RF Cavity

cavity, SRF, klystron, vacuum

1091

T.-C. Yu, F.Y. Chang, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Z.K. Liu, C.H. Lo, C.L. Tsai, M.H. Tsai, Ch. Wang, M.-S. Yeh
NSRRC, Hsinchu, Taiwan

In a high power RF system for accelerator application, the circulator is very important for protecting klystron or IOT from damage due to high reflection power from the cavity. When there is no beam current passing through the superconducting RF cavity of the accelerator, almost 100% RF power will be reflected from the cavity even the cavity is on resonance. The circulator shall be able to forward the reflected power to the load and remain good matching and isolation condition between ports at klystron and the cavity. However, for a ferrite material based circulator, the magnetic field within circulator would be temperature dependent which would cause the variation of input return loss and isolation between ports. Additional DC current driving electromagnet field is thus re-quired for compensating the temperature variation. Even with the compensating DC current, the circulator is still not ideal for practical operation especially when the performance of the circulator is strongly phase dependent. The phenomenon observed in actual operation with one set of SRF systems in NSRRC is thus reported in this article.

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MOPVA118

Impact of Trapped Magnetic Flux and Thermal Gradients on the Performance of Nb3Sn Cavities

cavity, niobium, site, target

1127

D.L. Hall, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
D. Liarte, J.P. Sethna
Cornell University, Ithaca, New York, USA

Trapped magnetic flux is known to degrade the quality factor of superconducting cavities by increasing the surface losses ascribed to the residual resistance. In Nb3Sn cavities, which consist of a thin layer of Nb3Sn coated on a bulk niobium substrate, the bimetallic interface results in a thermal current being generated in the presence of a thermal gradient, which will in turn generate flux that can be trapped. In this paper we quantify the impact of trapped flux, from either ambient fields or thermal gradients, on the performance of the cavity. We discover that the sensitivity to trapped flux, a measure of the increase in residual resistance as a function of the amount of flux trapped, is a function of the accelerating gradient. A theoretical framework to explain this phenomenon is proposed, and the impact on the requirements for operating a Nb3Sn cavity in a cryomodule are considered.

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MOPVA122

Microphonics Studies of the CBETA Linac Cryomodules

cavity, cryomodule, linac, SRF

1138

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

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

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MOPVA123

Cornell Sample Host Cavity: Recent Results

cavity, niobium, SRF, electron

1142

J.T. Maniscalco, D.L. Hall, M. Liepe, R.D. Porter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V.M. Arrieta, S.R. McNeal, W.E. Williams
Ultramet, Pacoima, California, USA

Funding: NSF-PHY 1416318 NSF-PHY 1549132
The Cornell sample host cavity is a 3.9~GHz testing system for RF analysis of novel superconducting surfaces. The cavity applies fields up to 100~mT on a removable and replaceable 5-inch sample plate in order to measure the surface resistance of the material under investigation. The cavity also includes a temperature-mapping system for localization of quench events and surface defects. In this paper, we present recent experimental results from the host cavity of niobium deposited onto molybdenum and copper substrates using chemical vapor deposition, in collaboration with industry partner Ultramet. The results indicate low BCS resistance and good adhesion but also areas of high residual resistance due to chemical and morphological defects.

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MOPVA128

RF Performance of Nitrogen-Doped Production SRF Cavities for LCLS-II

cavity, SRF, niobium, accelerating-gradient

1156

D. Gonnella, A. Burrill, M.C. Ross
SLAC, Menlo Park, California, USA
S. Aderhold, A. Grassellino, C.J. Grimm, T.N. Khabiboulline, O.S. Melnychuk, S. Posen, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA
E. Daly, G.K. Davis, F. Marhauser, K.M. Wilson
JLab, Newport News, Virginia, USA

Funding: DOE and the LCLS-II Project
The Linac Coherent Light Source II (LCLS-II) requires 280 9-cell superconducting RF cavities for operation in continuous wave mode. Two vendors have previously been selected to produce the cavities, Research Instruments GmbH and Ettore Zanon S.p.a. Here we present results from manufacturing and cavity preparation for the cavities constructed at these two vendors for LCLS-II. We show how the cavity preparation method has been changed mid-production in order to improve flux expulsion in the cavities and maintain high performance in realistic magnetic field environments (~5 mG). Additionally, we show that the nitrogen-doping process has been carried out successfully and repeatedly on over 70 cavities.

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MOPVA133

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

linac, cavity, electron, SRF

1170

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

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

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MOPVA143

Trim Tuning of SPS-Series DQW Crab Cavity Prototypes

cavity, target, simulation, controls

1187

S. Verdú-Andrés, J. Skaritka, Q. Wu
BNL, Upton, Long Island, New York, USA
S. Baurac, C.H. Boulware, T.L. Grimm, J.A. Yancey
Niowave, Inc., Lansing, Michigan, USA
W.A. Clemens, E.A. McEwen, H. Park
JLab, Newport News, Virginia, USA
H. Park
ODU, Norfolk, Virginia, USA
A. Ratti
LBNL, Berkeley, California, USA
A. Ratti
SLAC, Menlo Park, California, USA

Funding: Work partially supported by US DOE via BSA LLC contract No.DE-AC02-98CH10886 and by the US LARP program.
The final steps in the manufacturing of a superconducting RF cavity involve careful tuning before the final welds to match the target frequency as fabrication tolerances may introduce some frequency deviations. The target frequency is chosen based on analysis of the shifts induced by remaining processing steps including acid etching and cool down. The baseline fabrication of a DQW crab cavity for the High Luminosity LHC (HL-LHC) envisages a first tuning before the cavity subassemblies are welded together. To produce a very accurate final result, subassemblies are trimmed to frequency in the last machining steps, using a clamped cavity assembly for RF measurements. This paper will describe the trim tuning of one of the SPS prototype DQW crab cavities fabricated by Niowave.

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TUOAB3

Development of Wide Dynamic Range Beam Loss Monitor System for the J-PARC Main Ring

detector, beam-losses, injection, extraction

1248

K. Satou, N. Kamikubota, T. Toyama, S. Yamada
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
S.Y. Yoshida
Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan

The new beam loss monitor (BLM) system now in operation at the main ring of J-PARC consists of an isolated front-end current to voltage converter, a VME-based 24 bit ADC system. A dual detector system employs a proportional-type gas chamber (PBLM) and an air-filled ionization chamber (AIC). The system shows a wide dynamic range of 160 dB. It can detect the low level signal that would arise in the case of the detection of residual dose in the ring itself after the beam has been turned off as well as an event such as high level beam loss at the collimators. The signal rise time of the waveform obtained is 17 us which fast enough to meet the speed requirement of the Machine Protection System (MPS); which is that the MPS should dump the beam within 100 us when the beam loss signal exceeds the reference levels set in the ADC system.

Slides TUOAB3 [2.692 MB]

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TUZB1

Final Results From the Clic Test Facility (CTF3)

linac, acceleration, emittance, beam-loading

1269

R. Corsini
CERN, Geneva, Switzerland

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

Slides TUZB1 [23.702 MB]

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TUPAB002

Material Tests for the ILC Positron Source

target, positron, electron, photon

1293

A. Ushakov, G.A. Moortgat-Pick
University of Hamburg, Hamburg, Germany
K. Aulenbacher, Th. Beiser, P. Heil, V. Tioukine
IKP, Mainz, Germany
A. Ignatenko, S. Riemann
DESY Zeuthen, Zeuthen, Germany
A.L. Prudnikava, Y. Tamashevich
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

The positron source is a vital system of the ILC. The conversion target that yields 10¹⁴ positrons per second will undergo high peak and cyclic load during ILC operation. In order to ensure stable long term operation of the positron source the candidate material for the conversion target has to be tested. The intense electron beam at the Mainz Microtron (MAMI) provides a good opportunity for such tests. The first results for Ti6Al4V are presented which is the candidate material for the positron conversion target as well as for the exit window to the photon beam absorber.

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TUPAB006

Achievement of Stable Pulsed Operation at 31 MV/m in the STF-2 Cryomodule for the ILC

cavity, cryomodule, radiation, accelerating-gradient

1308

Y. Yamamoto, T. Dohmae, M. Egi, K. Hara, T. Honma, E. Kako, Y. Kojima, T. Konomi, N. Kota, T. Kubo, T. Matsumoto, T. Miura, H. Nakai, K. Nakanishi, G.-T. Park, T. Saeki, H. Shimizu, T. Shishido, T. Takenaka, K. Umemori
KEK, Ibaraki, Japan

In the Superconducting RF Test Facility (STF) in KEK, the cooldown test for the STF-2 cryomodule with 12 cavities has been done totally three times since 2014. In 2016, the 3rd cooldown test for the STF-2 cryomodule including the capture cryomodule with 2 cavities, which was used for Quantum Beam Project in 2012, was successfully done. The main purpose is the vector-sum operation with 8 cavities at average accelerating gradient of 31 MV/m as the ILC specification, and the others are the measurement for Lorenz Force Detuning (LFD) and unloaded Q value, and Low Level RF (LLRF) study, etc. During 8 cavities operation, piezo actuators were used for the compensation of LFD, and the feed-forward and vector-sum control system by LLRF worked perfectly for keeping the lowest forward power and the stable flat-top of accelerating gradient. In this paper, the result for the STF-2 cryomodule in the 3rd cooldown test will be presented in detail.

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TUPAB007

Analysis of the Dependability of the LHC Quench Detection System During LHC Run 2 and Further System Evolution

radiation, software, electronics, superconducting-magnet

1311

T. Podzorny, D.O. Calcoen, R. Denz, A.P. Siemko, J. Spasic, J. Steckert
CERN, Geneva, Switzerland

The quench detection system (QDS) of the LHC superconducting circuits is an essential part of the LHC machine protection and ensures the integrity of key elements of the accelerator. The large amount of hardwired and software interlock channels of the QDS requires a very high system dependability in order to reduce the risk of affecting the successful operation of the LHC. This contribution will present methods and tools for systematic fault tracking and analysis, and will discuss recent results obtained during the LHC production run in 2016. Measures for maintaining and further improving of the system performance will be explained. An overview of the further evolution of the LHC QDS also in view of the upcoming High Luminosity Upgrade of the LHC will be given.

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TUPAB010

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

cavity, linac, collider, linear-collider

1322

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

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

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TUPAB016

The CLIC Main Linac Module Updated Design

alignment, linac, klystron, luminosity

1345

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

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

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TUPAB017

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

beam-loading, experiment, klystron, linac

1348

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

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

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TUPAB030

Construction and Status of the Thrice Recirculating S-DALINAC

alignment, recirculation, lattice, dipole

1384

M. Arnold, R. Grewe, J. Pforr, N. Pietralla
TU Darmstadt, Darmstadt, Germany
C. Eschelbach, M. Lösler
Frankfurt University of Applied Sciences, Frankfurt am Main, Germany
F. Hug
IKP, Mainz, Germany
T. Kürzeder
HIM, Mainz, Germany

Funding: Work supported by DFG through RTG 2128 and CRC 634.
From 1991 until 2015 the S-DALINAC (Superconducting-DArmstadt-LINear-ACcelerator) was operated as a twice recirculating electron accelerator. Its design energy of 130 MeV in cw-operation was not reached so far due to a lower quality factor of the SRF cavities and thus a higher dissipated power to the helium bath. In 2015/2016 a third recirculation has been built. Enabling a fourth passage through the main linac, the accelerating gradients can be reduced to fit the resulting dissipated power to the available cooling power for running at design energy. The upgrade to a thrice recirculating accelerator required the reconstruction of main parts of the existing lattice as well as an installation of a new beam line. All magnets had to be aligned carefully in position and orientation using high-precision metrology sensors. This contribution will present an overview of the construction and the alignment process. A latest status of the commissioning will be given.

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TUPAB044

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

electron, simulation, cavity, linac

1424

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

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

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TUPAB056

New Achievements of the Laser System for RF-Gun at SuperKEKB Injector

laser, gun, electron, experiment

1452

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

For realizing high charge and low emittance electron and positron beams in SuperKEKB, we have been making improvements in current laser system for RF-gun. In order to realize more excellent thermal management in current laser system at high repetition rate operation, novel soldering Yb:YAG thin disk and copper tungsten heat sink laser head is manufactured via gold tin solder. Comparing with old design, less residual stress is introduced and more efficient thermal removal can be obtained. These new soldering laser heads are placed into a compact vacuum chamber and cooled by Peltier plates directly. This design can realize higher gain and amplification factor in regenerative amplifier and multi-pass amplifier. In addition, the compact and simple cooling method can achieve excellent thermal management for the purpose of realize laser operation at high repetition rate for following phases of SuperKEKB project. A perspective towards the next step experiment is also presented in this paper.

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TUPAB095

The New MAX IV Gun Test Stand

gun, laser, emittance, cathode

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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TUPAB103

Orbit Correction With Path Length Compensation Based on Rf Frequency Adjusments in TPS

electron, feedback, site, photon

1553

P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Huang, C.-C. Kuo, C.C. Liang, Y.-C. Liu, H.-J. Tsai, F.H. Tseng
NSRRC, Hsinchu, Taiwan

The 3 GeV Taiwan Photon Source has been routinely operated for public users since September 2016. Orbit reproducibility and stability are critical for the quality of user experiments. Ambient temperature variations and earth tides can cause a change in circumference, changing in turn the beam energy, and orbit drift. Therefore both, orbit correction and rf frequency adjustments are necessary to keep the ring circumference constant. A Fast Orbit Feedback (FOFB) system combined with rf frequency correction deduced from the fast corrector strengths is applied to the FOFB routine. The correlation between the measured frequency variation with ambient temperature and earth tides is also reported in this article.

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TUPAB108

Upgrade of BTS Control System for the Taiwan Light Source

controls, EPICS, interface, GUI

1570

Y.-S. Cheng, J. Chen, K.T. Hsu, K.H. Hu, C.H. Huang, D. Lee, C.Y. Liao, C.Y. Wu
NSRRC, Hsinchu, Taiwan

The Taiwan Light Source (TLS) is a third generation of synchrotron light source, and it has been operated since 1993. The TLS control system is a proprietary design. It was performed minor upgrade several times to avoid obsolete of some system components and keep up-to-date during last two decades. The control system of BTS (Booster-to-Storage ring) transport line includes control interfaces of power supplies, screen monitors, vacuum and temperature. The cPCI (CompactPCI) based EPICS IOC (Input Output Controller) has been adopted for renewing TLS BTS control system to replace the existed VME based ILC (Intelligent Local Controller) to be as an easy-to-maintain control environment. Moreover, each TLS control console supports not only the existing control software interfaces, but also the newly developed EPICS graphical user interfaces. Upgraded TLS BTS control system had been successfully commissioning in February 2017. Compare new system with old system, new system provides more functionality, fast response, and highly reliability. The efforts are summarized at this paper.

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TUPAB109

Study on Injection with Pulsed Multipole Magnet for SPS Storage Ring

injection, multipole, kicker, storage-ring

1573

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

Pulsed multipole magnet (PM) has zero magnetic field at the centre, therefore it introduces no perturbation to the stored beam. It has been demonstrated that this injection scheme is able to minimise the oscillation of the stored beam, and thus make it suitable for top-up operation. To investigate the suitability of employing this injection method at Siam Photon Source, PM was modelled and optimised for best performance using particle tracking based method. This work presents injection optimisation process with PM considering various constraints such as position of injected beam, injection conditions, and effects of installed IDs.

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TUPAB130

Status of the LCLS-II Superconducting RF Linac

cryomodule, cavity, linac, FEL

1630

A. Burrill
SLAC, Menlo Park, California, USA

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

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TUPAB132

A Novel Dual-Mode Dual-Frequency Linac Design

impedance, cavity, network, distributed

1634

M.H. Nasr, S.G. Tantawi
SLAC, Menlo Park, California, USA

In this paper we will present a new type of accelerator structure that operates simultaneously at two accelerating modes with two frequencies. The frequencies are not harmonically related, but rather have a common sub-harmonic. This design will use a recently developed parallel-feeding network that feeds every cavity cell independently using a distributed feeding network. This will overcome many of the practical complications of coupled cell structure. We will provide the theoretical background for our dual-mode design as well as present our optimized design that operates at C and X bands simultaneously and provides enhanced gradient and efficiency compared to single-mode designs.

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TUPIK034

NSC KIPT Neutron Source on the Base of Subcritical Assembly With Electron Linear Accelerator Driver

neutron, target, electron, shielding

1754

A.Y. Zelinsky, I.M. Karnaukhov, A. Mytsykov, I. Ushakov
NSC/KIPT, Kharkov, Ukraine
Y.L. Chi
IHEP, Beijing, People's Republic of China
Y. Gohar
ANL, Argonne, Illinois, USA

National Science Center Kharkov Institute of Physics & Technology (NSC KIPT) together with ANL, Chicago, USA developed up to date scientific facility that is Neutron Source on the base of subcritical assembly driven with 100 MeV/100 kW electron accelerator. During bombarding of the Tungsten or Uranium targets the electron beam generates the original neutrons that are multiplied in the facility core of low enriched uranium trough the fission process. The maximal value of the neutron multiplication factor is 0.98. So the total neutron flux output is increased as much as 50 times and is 2·10 13 n·cm^-2·c-1. The subcriticality of the system eliminates the possibility of self-sustained chain reaction existence that increases the nuclear safety of the facility drastically. The neutron source mentioned above is the first facility of such type in the world. The results that will be obtained at studies of neutron characteristics of the neutron source with low enriched uranium core and during optimization of the operation modes of the facility systems will became the scientific background for the further development of the safe, ecological nuclear energetics of the future.

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TUPIK047

FAIR Control Centre (FCC) - Concepts and Interim Options for the Existing GSI Main Control Room

controls, experiment, proton, ion

1791

M. Vossberg, K. Berkl, S. Reimann, P. Schütt, R.J. Steinhagen, G. Stephan
GSI, Darmstadt, Germany

The 'Facility for Anti-Proton and Ion Research' (FAIR) which is presently under construction, extends and supersedes the existing GSI. Present operation still largely relies on laborious manual tuning based on analogue signals routed directly to the existing control room. The substantial scope increase from 3 to more than 8 FAIR accelerators requires more intricate and precise control across longer accelerator chains, while providing a high degree of multi-user operation, with facility reconfiguration required on time-scales of a few times per week. A new FAIR Control Centre (FCC) is being planned to accommodate the required larger accelerator crews as well as accelerator-based experiments. While targeting a single control room for up to ~35 people, emphasis is put on ergonomics, operational processes, and minimising unnecessary strain on personnel already during the design stage. This contribution presents digital control room concepts, console layout, and beam-production-chain paradigms aimed at achieving good operational performances and that influence the new FCC design. Prior to FCC completion, interim upgrade options of the existing control room are being investigated.

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TUPIK051

Statistics on High Average Power Operation and Results from the Electron Beam Characterization at PITZ

gun, cathode, vacuum, Windows

1806

Y. Renier, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, T. Rublack, C. Saisa-ard, F. Stephan, Q.T. Zhao
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
M. Bousonville, S. Choroba, S. Lederer
DESY, Hamburg, Germany

The Photo Injector Test Facility at DESY in Zeuthen (PITZ) develops, tests and characterizes high brightness electron sources for FLASH and European XFEL. Since these FELs work with superconducting accelerators in pulsed mode, also the corresponding normal-conducting RF gun has to operate with long RF pulses. Generating high beam quality from the photo-cathode RF gun in addition requires a high accelerating gradient at the cathode. Therefore, the RF gun has to ensure stable and reliable operation at high average RF power, e.g. 6.5 MW peak power in the gun for 650 μs RF pulse length and 10 Hz repetition rate for the European XFEL. Several RF gun setups have been operated towards these goals over the last years. The latest gun setup is in operation since March 2016 and includes RF Gun 4.6 with an improved contact spring design. The RF input distribution consists of a coaxial coupler, a T-combiner and 2 RF windows from DESY production. In this contribution we will present statistics on the high average power operation and results from the characterization of the produced electron beam.

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TUPIK052

Fast Automatic Ramping of High Average Power Guns

cavity, gun, resonance, feedback

1809

Y. Renier
DESY Zeuthen, Zeuthen, Germany
M.K. Grecki, O. Hensler, S. Pfeiffer
DESY, Hamburg, Germany

The electron guns at PITZ, FLASH and European XFEL are standing wave structures which operate at high average power (>40 kW) to produce long trains of high quality beams. This amount of power heats the cavity surface enough to change signi'cantly the gun resonance frequency. As consequence, to keep the re'ection low, the RF power ramp must be enough slow to permit the water cooling system to keep the gun temperature close to the set-point. Also, as the temperature probe sits close to the surface of the iris, the required gun temperature set-point to maintain the gun on resonance is a function of the average power. The RF power ramping is a difficult process in which temperature and re'ection must be monitored to adjust accordingly the temperature set-point and the ramping speed of the RF power. An automatic software to adjust the RF frequency and the temperature set-point of the PITZ gun in parallel to the RF power ramping has been developed. The use of this software has signi'cantly reduced the time spent to start up the gun or to recover from interlocks, increasing the time spent at nominal parameters which would also be very important for user facilities.

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TUPIK054

The MAMI-C Accelerator: 25 Years of Operation and Strategies for the Next Decade

klystron, experiment, microtron, electron

1816

M. Dehn, K. Aulenbacher, F. Fichtner, R.G. Heine, P. Jennewein, W. Klag, H.-J. Kreidel, J.R. Röthgen, V. Tioukine
IKP, Mainz, Germany

Funding: Work supported by DFG (CRC 1044) and the German federal state of Rheinland-Pfalz
The Mainz Microtron Accelerator (MAMI-C) is a staged Race Tack Microtron (RTM) accelerator for 100μA polarised electrons up to 1.6 GeV energy. This report addresses the problems and our strategies to reliably operate the MAMI-C Accelerator for at least another ten years and what lessons have been learned for the new Mainz Energy recovering Superconducting Accelerator (MESA).

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TUPIK057

The Real-Time Waveform Mask Interlock System for the RF Gun Conditioning of the ELI-NP Gamma Beam System

gun, vacuum, real-time, software

1822

S. Pioli, D. Alesini, A. Gallo, L. Piersanti
INFN/LNF, Frascati (Roma), Italy
F. Cardelli, L. Palumbo
University of Rome La Sapienza, Rome, Italy
D.T. Palmer
Istituto Nazionale di Fisica Nucleare, Milano, Italy

The new Gamma Beam System (GBS), within the ELI-NP project, under installation in Magurele (RO) by INFN, as part of EuroGammas consortium, can provide gamma rays that open new possibilities for nuclear photonics and nuclear physics. ELI-GBS gamma rays are produced by Compton back-scattering to get monochromaticity (0,1% bandwidth), high flux (10¹³ photon/s the highest in the world), tunable directions and energies up to 19 MeV. Such gamma beam is obtained when a high-intensity laser collides a high-brightness electronbeam with energies up to 720 MeV. The RF-Gun, made with the novel clamping gasket technique, working in '-mode at 100 Hz with a max. RF input of 16 MW, RF peak field of 120 MV/m and filling time of 420 ns was fully tested and conditioned few month ago at ELSA. This paper will describe the real-time fast-interlock system based on waveform mask technique used during RF Gun conditioning in order to monitor on-line reflected RF signals for a faster pulse-to-pulse detection of breakdowns and to ensure the safety of Gun and modulator tripping such devices before next RF pulse.

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TUPIK058

The Machine Protection System for the ELI-NP Gamma Beam System

vacuum, electron, laser, gun

1824

S. Pioli, D. Alesini, D. Di Giovenale, G. Di Pirro, A. Gallo, L. Piersanti, A. Vannozzi, A. Variola
INFN/LNF, Frascati (Roma), Italy
F. Cardelli, L. Palumbo
University of Rome La Sapienza, Rome, Italy

The new Gamma Beam System (GBS), within the ELI-NP project, under installation in Magurele (RO) by INFN, as part of EuroGammas consortium, can provide gamma rays that open new possibilities for nuclear photonics and nuclear physics. ELI-GBS gamma rays are produced by Compton back-scattering to get monochromaticity (0,1% bandwidth), high flux (10¹³ photon/s the highest in the world), tunable directions and energies up to 19 MeV. Such gamma beam is obtained when a high-intensity laser collides a high-brightness electron beam with energies up to 720 MeV with a repetition rate of 100 Hz in multi-bunch mode with trains of 32 bunches. An advanced Machine Protection System was developed in order to ensure proper operation for this challenging facility. Such system operate on different layers of the control system to be interfaced with all sub-systems of the control system. It's equipped with different beam loss monitors based on Cherenkov optical fiber, hall probes, fast current transformer together with BPM and an embedded system based on FPGA with distributed I/O over EtherCAT to monitor vacuum and RF systems which requires fast response to be interlocked within the next RF pulse.

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TUPIK060

Human Factors in the Design of Control-Rooms for ESS

controls, factory, target, interface

1830

P. Le Darz, S.G. Collier, M. Rosenqvist
IFE, Halden, Norway

Funding: The Research Council of Norway [ForskningsrÃ¥det]
Norway contributes in kind to the building of ESS. Part of this work concerns the human factors aspects of the control-rooms for the operators of the machine. IFE is applying international standards on human factors (e.g., ISO 11064) to the design of the main control-room (MCR) and a local control-room (LCR). The work is also intended to satisfy regulatory requirements. So far, for the MCR, we have completed a concept design. User requirements clarification involved interviews with stakeholders and visits to similar facilities. Concept design for the MCR was iterative and involved a user reference-group set up for the project. During several workshops, alternatives for layout and workstations were discussed and modeled using 3D graphics. The chosen concept design and 3D model were then checked against standards. The resulting design was approved by the user-group and now goes forward to detailed design and realization. We have also completed detailed design of the LCR so that it is available for commissioning before the MCR is built. IFE also contributes to the human-machine interface design in other projects, such as for alarm system design and a logbook software application.

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TUPIK063

The Configurable Software Interlock System for HLS-II

software, EPICS, controls, vacuum

1836

Y. Song, G. Liu, K. Xuan
USTC/NSRL, Hefei, Anhui, People's Republic of China

The interlock system is an essential component for an accelerator facility. A configurable software interlock system(SIS) is designed for Hefei Light Source II (HLS-II), which complements the hardware interlock system to ensure equipment and operators' safety. The system is developed using Python under the EPICS framework with the method of separating the configuration file from the interlock program. The interlock logic is completely determined by the configuration file and its nested tree structure is easy to expand. The test results indicate that the new software interlock system is reliable, flexible and convenient to operate. This paper will describe the design and the construction of HLS-II SIS.

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TUPIK070

Main Control System of the Linear Accelerator for the HUST THz-FEL

controls, gun, beam-diagnostic, diagnostics

1858

B. Tang, Q.S. Chen, T. Hu, J. Jiang, Y.Q. Xiong
HUST, Wuhan, People's Republic of China

A free-electron laser terahertz radiation source(THz-FEL) with a table-top scale is constructed in Huazhong University of Science & Technology. The whole facility is under joint-debugging currently, and main measured parameters have already matched with design targets. This paper describes the main control system of the Linac-based injector, especially auto-matching and auto-commissioning modules. The former occurs at the begin of daily operation, which contains one key pre-heating and searching the best electric parameters and RF parameters automatically based on last operation status. The later applies in beam commissioning for both Linac and transport line combining with beam diagnostic system, which could save operation time and improve commissioning efficiency. Moreover, real-time monitoring and controlling for water-cooling and vacuum states are inserted in the main control system to protect the accelerator.

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TUPIK078

Machine Protection Risk Management of the ESS Target System

target, proton, timing, cryogenics

1876

R. Andersson, E. Bargalló, L.S. Emås, J. Harborn, A. Lundgren, U. Odén, J. Ringnér, K. Sjögreen
ESS, Lund, Sweden

The European Spallation Source target system is, together with the proton linac, the main component in the spallation process. ESS will use a 4-ton, helium-cooled, rotating tungsten target for this purpose, and its protection and availability is paramount to the success of ESS. High demands are placed on all of the target equipment, including cooling, movement, rotation, and timing, in order to reach the facility-wide 95% availability goal for neutron production. Machine protection has defined a set of protection functions that are to be implemented for the target system. This paper describes the development of these protection functions through the use of classic HAZOPs combined with modern safety standard lifecycle management. The implementation of these functions is carried out through close collaboration between the target system owners and the machine protection group at ESS.

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TUPIK083

Methodology, Design and Physical Deployment of Highly Dependable PLC Based Interlock Systems for ESS

vacuum, PLC, interface, hardware

1887

M. Zaera-Sanz, S. Kövecses, A. Nordt
ESS, Lund, Sweden

Approximately 350 resistive magnets, 110 vacuum gate valves and 30 interceptive devices will be installed in the 600 m long linear accelerator at ESS, transporting the proton beam from the source to the target station. In order to protect this equipment from damage and to take the appropriate actions required to minimise recovery time, a dedicated set of PLC based interlock systems are being designed. The magnet powering interlock system will safely switch off a Power Converter (PC) upon the detection of an internal magnet or PC failure. The interceptive devices interlock system will protect Faraday cups, wire scanners, EMUs and LBMs from a beam mode that they cannot withstand by allowing/removing permission for movement. The vacuum gates interlock system will protect the gate valves in case of unexpected closing. The target interlock system will protect the target system by acting on motors, compressors, etc. These interlock systems will inform the beam interlock system to inhibit further beam operation by stopping beam if required. The methodology, design and physical deployment of the four interlock systems will be presented.

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TUPIK086

Modelling the Radioactivity Induced by Slow-Extraction Losses in the CERN SPS

extraction, proton, detector, radioactivity

1897

M.A. Fraser, D. Björkman, K. Cornelis, B. Goddard, V. Kain, P.M. Schicho, C. Theis, H. Vincke
CERN, Geneva, Switzerland

Resonant slow extraction is used to provide an intense quasi-DC flux of high-energy protons for the Fixed Target (FT) physics programme at the CERN Super Proton Synchrotron (SPS). The unavoidable beam loss intrinsic to the extraction process activates the extraction region and its equipment. Although the radiation dose to equipment has an impact on availability, the cool-down times required to limit dose to the personnel carrying-out maintenance of the accelerator also pose important restrictions, and ultimately limit the number of protons on target. In order to understand how the extracted proton flux affects the build-up and subsequent cool-down of the induced activation, a model based on a simple empirical relationship has been developed and shown to predict the measured radioactive decay at ionisation chambers located along the extraction region. In this contribution, the empirical model is described, its strengths and limitations discussed, and its application as a predictive tool for estimating cool-down times as a function of extracted proton flux demonstrated.

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TUPIK087

Phase Advance Interlocking Throughout the Whole LHC Cycle

quadrupole, optics, kicker, software

1901

K. Fuchsberger, A. Calia, M.A. Galilée, G.H. Hemelsoet, M. Hostettler, D. Jacquet, J. Makai, M. Schaumann
CERN, Geneva, Switzerland

Each beam of CERN's Large Hadron Collider (LHC) stores 360 MJ at design energy and design intensity. In the unlikely event of an asynchronous beam dump, not all particles would be extracted immediately. They would still take one turn around the ring, oscillating with potentially high amplitudes. In case the beam would hit one of the experimental detectors or the collimators close to the interaction points, severe damage could occur. In order to minimize the risk during such a scenario, a new interlock system was put in place in 2016. This system guarantees a phase advance of zero degrees (within tolerances) between the extraction kicker and the interaction point. This contribution describes the motivation for this new system as well as the technical implementation and the strategies used to derive appropriate tolerances to allow sufficient protection without risking false beam dump triggers.

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TUPIK089

Studies on Luminous Region, Pile-up and Performance for HL-LHC Scenarios

luminosity, simulation, optics, detector

1908

L.E. Medina Medrano, G. Arduini, R. Tomás
CERN, Geneva, Switzerland
L.E. Medina Medrano
UGTO, Leon, Mexico

Funding: Research supported by the HL-LHC project and the Beam project (CONACYT, Mexico).
Studies on luminous region and pile-up density are of great interest for the experiments at the future High Luminosity LHC (HL-LHC) in order to optimize the detector performance. The evolution of these parameters at the two main interaction points of the HL-LHC along optimum physics fills is studied for the baseline and alternative operational scenarios with the latest set of parameters, including a refined description of the longitudinal bunch profile. Results are discussed in terms of a new figure-of-merit, the effective pile-up density.

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TUPIK094

Transverse Feedback Parameter Extraction from Excitation Data

feedback, kicker, pick-up, damping

1920

G. Kotzian
CERN, Geneva, Switzerland

In this paper we present a simple and fast approach to extract essential parameters of a transverse feedback system such as phase advances between pick-ups and kickers, fractional tune, kicker delay, or per-bunch transverse activity from discrete-time samples of position signals. In this approach the beam is excited and subsequent beam oscillations are recorded. Given that any number of pick-ups can be evaluated at once with only a marginal increase of transverse beam size this method is suitable for regular health checks of a transverse feedback system, e.g., for every injection. The fundamental idea relies on the reconstruction of the transverse phase space by means of digital filters. We sketch a simple mathematical model to illustrate the underlying method. Examples are given together with a set of filter kernels for the fractional tunes of the LHC transverse feedback system.

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TUPIK100

Methodology Applied for Dependability Studies on the Compact Linear Collider

simulation, quadrupole, linac, collider

1943

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

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

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TUPIK102

Introduction of Operating Procedures at TPS

controls, injection, electron, vacuum

1951

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

The Taiwan Photon Source (TPS) is the latest generation of 3 GeV synchrotron light source which subsystem includes magnet, power supply, vacuum, RF system, insertion device, control system, etc. The operating procedures and checking items are complex. To speed up the machine start-up and shut-down procedures, check the system's status, and prevent misoperation, we summarize the procedures for routine operation and develop the integrated control interface, which concentrates most machine information and control functions into a single window. This interface clearly indicates the machine status and improves operational efficiency.

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TUPIK103

Development of Automatic Turn-on Systems for TPS Machine

injection, linac, controls, booster

1954

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

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

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TUPIK105

The Design Improvement of Horizontal Stripline Kicker in TPS Storage Ring

kicker, impedance, storage-ring, vacuum

1961

P.J. Chou, C.K. Chan, C.-C. Chang, K.T. Hsu, K.H. Hu, C.K. Kuan, I.C. Sheng
NSRRC, Hsinchu, Taiwan

We plan to replace the existing horizontal stripline kicker of the transverse feedback system with an improved design. Large reflected power was observed at the downstream port of stripline kicker driven by the feedback amplifier. A rapid surge of vacuum pressure was observed when we tested the high current operation in TPS storage ring in April 2016. A burned feedthrough of the horizontal stripline kicker was discovered during a maintenance shutdown. The improved design is targeted to reduce the reflection of driving power from feedback system and to reduce beam induced RF heating. This major modification of the design is described. The results of RF simulation performed with the electromagnetic code GdfidL are reported as well.

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TUPIK107

Upgrade of the Existing PID Controller and Oxygen Detection Alarm System for SRF Modules Operating in the Taiwan Light Source

SRF, controls, electronics, status

1968

F.-T. Chung, F.Y. Chang, L.-H. Chang, M.H. Chang, L.J. Chen, M.-C. Lin, Z.K. Liu, C.H. Lo, C.L. Tsai, Ch. Wang, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan

A Cornell-type superconducting RF cavity module was installed in the Taiwan Light Source (TLS) in 2004. New control electronics for the existing SRF modules have been designed, based on the original designs. In addition to the functions for operation, this SRF electronics system in the TLS also provides protection for the SRF modules and cryogenic system. This paper presents the SRF electronics modifications, which will enhance machine protection and make it easy to adjust and optimize operational parameters.

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TUPIK109

Accelerators and Their Ghosts

database, network, target, proton

1975

M. Reščič, R. Seviour
University of Huddersfield, Huddersfield, United Kingdom
W. Blokland
ORNL, Oak Ridge, Tennessee, USA

The issue of particle accelerator reliability is a problem that currently is not fully defined, understood nor addressed. Conventional approaches to reliability (e.g. RBDs) struggle due to a lack of data about specific component/system reliability and failure. There is a large body of beam current data retrievable from operating accelerators that contains detailed information about the accelerator behaviour, both before and after a machine trip has occurred. Analysing this data could provide insight and help develop a new approach to address accelerator reliability. In this paper, we propose a data-driven approach to detecting emergent behaviour in particle accelerators. Instead of attempting to identify every possible failure of a machine we propose an alternative approach based around a change in perspective, to knowing the normal default operational behaviour of a machine. Taking action when a ghost in the machine emerges that causes accelerator wide aberrant changes to normal machine behaviour.

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TUPVA005

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

luminosity, experiment, emittance, 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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TUPVA006

Lessons Learnt from the 2016 LHC Run and Prospects for HL-LHC Availability

luminosity, proton, target, radiation

2039

A. Apollonio, O. Rey Orozko, R. Schmidt, M. Valette, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland

The LHC exhibited unprecedented availability during the 2016 proton run, producing about 40 fb-1 of integrated luminosity, surpassing the sum of production during the 4 previous years. This was achieved while running steadily with a peak luminosity above the design target of 1034 cm- 2s⁻¹. Individual system performance and an increased experience operating the LHC were fundamental for these achievements, following the consolidations and improvements deployed during the Long Shutdown 1 and the Year End Technical Stop in 2015. The implications of this excellent performance in the context of the High Luminosity LHC are discussed in this paper, with the goal of defining the possible integrated luminosity reach of HL-LHC when considering the different operating conditions and the newly developed systems and technologies.

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TUPVA012

Beam Related Machine Protection of the Future Circular Collider

proton, collider, dipole, beam-losses

2063

Y.C. Nie, M. Jonker, R. Schmidt
CERN, Geneva, Switzerland

In the Future Circular Collider (FCC) study, each nominal proton beam at top particle energy of 50 TeV has an energy of 8500 MJ, which is more than 20 times the energy of today's Large Hadron Collider (LHC) beam. Machine protection of such a high-energy and high-energy density accelerator becomes very challenging. In this paper, preliminary considerations of beam related machine protection issues of the FCC will be reported. Based on the current optics design, a few major critical equipment failures that could potentially lead to very fast (within a few turns) beam losses have been studied. The serious failure scenarios that have been considered, typically occurring at locations with high beta functions, include powering failures of normal conducting magnets, quenches of superconducting magnets as well as critical RF failures. Some fundamental questions related to the beam interlock system, e.g., the need for additional particle free abort gaps to shorten the synchronization time before executing a beam dump, will be discussed.

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TUPVA014

The 2016 Proton-Nucleus Run of the LHC

luminosity, proton, experiment, ion

2071

J.M. Jowett, R. Alemany-Fernández, G. Baud, P. Baudrenghien, R. De Maria, R. De Maria, D. Jacquet, M.A. Jebramcik, A. Mereghetti, T. Mertens, M. Schaumann, H. Timko, M. Wendt, J. Wenninger
CERN, Geneva, Switzerland

For five of the LHC experiments the second p-Pb collision run planned in 2016 offered the opportunity to answer a range of important physics questions arising from the surprise discoveries (e.g., flow-like collective phenomena in small systems) made in earlier Pb-Pb, p-Pb and p-p runs. However the diversity of the physics and their respective capabilities led them to request very different operating conditions, in terms of collision energy, luminosity and pile-up. These appeared mutually incompatible within the available one month of operation. Nevertheless, a plan to satisfy most requirements was developed and implemented successfully. It exploited different beam lifetimes at two beam energies of 4 Z TeV and 6.5 Z TeV, a variety of luminosity sharing and bunch filling schemes, and varying beam directions. The outcome of this very complex strategy for repeated re-commissioning and operation of the LHC included the longest ever LHC fill with luminosity levelled for almost 38 h. The peak luminosity achieved exceeded the design value by a factor 7.8 and integrated luminosity substantially exceeded the experiments' requests.

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TUPVA015

Radiation Levels at the LHC: 2012, 2015 and 2016 Proton Physics Operations in View of HL-LHC requirements

luminosity, radiation, proton, insertion

2075

C. Martinella, M. Brugger, S. Danzeca, R. Garcia Alia, Y. Kadi, O. Stein, C. Xu
CERN, Geneva, Switzerland

The variety of beam losses produced in the Large Hadron Collider (LHC) creates a mixed and complex radiation field. During 2012, 2015 and 2016, Beam Loss Monitors and RadMons were used to monitor the inte-grated dose and the High Energy Hadrons fluence in order to anticipate the electronics degradation and inves-tigate the cause of failures. The annual radiation levels are compared; highlighting the mechanisms in the pro-duction of beam losses and the impact of the different squeeze and crossing angle. In addition, the increase of beam-gas interaction is discussed comparing operations at 25 ns and 50 ns bunch spacing. A strategy is presented to allow for a continuous respective evaluation during the upcoming LHC and future High Luminosity LHC (HL-LHC) operations.

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TUPVA016

Identification and Analysis of Prompt Dose Maxima in the Insertion Regions IR1 and IR5 of the Large Hadron Collider

radiation, luminosity, dipole, quadrupole

2078

O. Stein, M. Brugger, S. Danzeca, R. Garcia Alia, Y. Kadi, M. Kastriotou, C. Martinella, C. Xu
CERN, Geneva, Switzerland

During the operation of the LHC the continuous particle losses create a radiation field in the LHC tunnel and the adjacent caverns. Exposed electronics and accelerator components show dose dependent accelerated aging effects and stochastic Single Event Effects which can lead to faults and downtime of the LHC. In order to achieve an optimal life duration, the position of the equipment is chosen in dependency of the amplitude of the radiation fields. Therefore, it is crucial to monitor the prompt dose distributions along the whole LHC. By using the LHC beam loss monitor and RadMon systems, the prompt dose during the accelerator operation is continuously monitored. Measurements in the long straight sections and the dispersion suppressors in IR1 (ATLAS) and in IR5 (CMS) have shown that the radiation levels have localised maxima which exceed the base line by 1 to 2 orders of magnitude. The analysis of these radiation peaks will be presented and the underlying loss mechanisms will be discussed. The results will help to identify areas not suitable for radiation sensitive electronics. Implications on the expected radiation levels for High-Luminosity LHC are also discussed.

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TUPVA019

Impact and Mitigation of Electron Cloud Effects in the Operation of the Large Hadron Collider

electron, cryogenics, injection, impedance

2085

G. Iadarola, B. Bradu, P. Dijkstal, L. Mether, G. Rumolo
CERN, Geneva, Switzerland

In 2015 and in 2016 the Large Hadron Collider has been routinely operated with 25 ns bunch spacing. With this beam configuration electron clouds develop in a large fraction of the beam chambers, in spite of a very large electron dose accumulated on the surfaces. This posed several challenges to different aspects of the beam operation. In particular, the machine settings had to be optimized in order to mitigate coherent and incoherent effects of the electron cloud on the beam dynamics while a specifically designed feed-forward control had to be implemented and optimized in order to dynamically adapt the regulations of the cryogenic system to the strong heat load deposited by the electron cloud on the beam screens of the cryogenic magnets. At the same time, the data collected from the different accelerator subsystems (heat loads, vacuum pressures, evolution of the bunch by bunch beam parameters) allowed to significantly improve our models and understanding on these phenomena.

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TUPVA022

Requirements for Crab Cavity System Availability in HL-LHC

luminosity, cavity, optics, proton

2097

M. Valette, A. Apollonio, J.A. Uythoven, D. Wollmann
CERN, Geneva, Switzerland

Funding: Research supported by the HL-LHC project.
Crab Cavities will be installed in the High Luminosity LHC in order to increase the effective peak luminosity through a partial compensation of the geometric factor. This will allow extending the levelling time resulting in an increased production of integrated luminosity. Based on the availability of the LHC during 2016 operation, the expected yearly-integrated luminosity of the future HL-LHC was estimated using a Monte Carlo model. Crab cavity faults were added to the observed failure distribu-tions and their impact on integrated luminosity produc-tion as a function of fault time and fault frequency was studied. This allows identifying a breakeven point in luminosity production and defining minimum system availability requirements for the crab cavities to reach the design goal of 250 fb-1 of integrated luminosity per year.

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TUPVA046

Beam Energy Scan With Asymmetric Collision at RHIC

cavity, emittance, 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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TUPVA048

Calculation of Particle Loss Maps for 2016 RHIC Gold-Gold Run

simulation, detector, kicker, radiation

2181

Y. Luo, K.A. Drees, W. Fischer, X. Gu, A. Marusic, G. Robert-Demolaize, V. Schoefer
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.
In the 2016 RHIC 100~GeV gold-gold (Au-Au) run, 20~mm orbit bumps were installed in the arcs to protect the experimental detectors from abort kicker prefiring. Chronic particle losses were observed in the arcs with these orbit bumps. Those particle losses are mainly from the 78+Au197 and 79+Au196 particles generated from bound-free pair production (BFPP) and electromagnetic dissociation (EMD) associated with the Au-Au collision at the IPs. In this article, we present simulated particle losses of 78+Au197 and 79+Au196 and calculate the particle loss distribution in the ring. The calculated particle loss maps are compared with operational observations.

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TUPVA057

Design Study for a Prototype Alvarez-Cavity for the Upgraded Unilac

cavity, DTL, ion, quadrupole

2205

M. Heilmann, X. Du, P. Gerhard, L. Groening, M. Kaiser, S. Mickat, A. Rubin
GSI, Darmstadt, Germany
A. Seibel
IAP, Frankfurt am Main, Germany

The design study describes the prototype Alvarez-tank of the new post-stripper of the UNILAC. A prototype with 17 drift tubes (including quadrupole singulets) of 3 m of total length and 2 m of diameter will be manufactured. This cavity features new drift tube shape profiles to provide for high shunt impedance at a maximum electric surface field of 1 Ek. Additionally, it allows realization and high power testing of an optimized stem configuration for field stabilization. In case of successful tuning and long-term operation at high power level, it shall be used as a first of series cavity of the new UNILAC post-stripper DTL.

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TUPVA069

Test of a High Power Room Temperature CH DTL Cavity

cavity, coupling, impedance, DTL

2237

N.F. Petry, S. Huneck, K. Kümpel, H. Podlech, U. Ratzinger, M. Schwarz
IAP, Frankfurt am Main, Germany

The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) is planned to deliver ultra-short neutron pulses at high intensities and repetition rates. As part of FRANZ a 175 MHz room temperature 5-gap CH DTL cavity was designed and built. Its main task will be focusing the particle bunch longitudinally at 2 MeV particle energy. Furthermore the CH cavity can also be used to increase the energy as well as decrease it by 0.2 MeV. The rebuncher and its cooling system is optimized to work with a 5 kW amplifier. The amplification system is intended to provide continuous power (cw mode). Due to its operating parameters being nearly identical to the requirements of the MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) Project, experience for future cavity designs was gained. This includes considerations concerning cooling with use of a 12 kW amplifier. The recent results of conditioning and high power tests will be presented.

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TUPVA074

Status of the modulated 3 MeV 325 MHz Ladder-RFQ

rfq, simulation, linac, dipole

2249

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

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

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TUPVA090

Performance and Status of the J-PARC Accelerators

linac, klystron, ion-source, extraction

2290

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

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

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TUPVA093

Radio-Activation Caused by Secondary Particles Due to Nuclear Reactions at the Stripper Foil in the J-PARC RCS

injection, proton, synchrotron, beam-losses

2300

M. Yoshimoto, H. Hotchi, S. Kato, M. Kinsho, K. Okabe, K. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The most important issue in realizing such a MW-class high-power routine beam operation is to keep machine activations within a permissible level, that is, to preserve a better hands-on-maintenance environment. Thus, a large fraction of our effort has been concentrated on reducing and managing beam losses. However the high residual activation is appeared around the stripper foils. It is caused by not primary particles due to the beam losses but secondary particles due to nuclear reaction at the foil. This radio-activation is an intrinsically serious problem for the RCS which adopts the charge exchange multi-turn beam injection scheme with the stripper foil. In this presentation, we report a detail measurement of the residual dose around the stripper foil together with the cause estimated based on simulation studies.

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TUPVA102

Effect of Beam Losses on Radio Frequency Quadrupole

rfq, proton, experiment, ion

2325

Q. Fu, P.P. Gan, S.L. Gao, F.J. Jia, H.P. Li, Y.R. Lu, Z. Wang, K. Zhu
PKU, Beijing, People's Republic of China

Funding: the National Basic Research Program of China (2014CB845503)
Most of existing high-current RFQs in the world encounter the degrade of beam transmission or unstable operation, even RF ramping can't go up to nominal design voltage after several years or long time beam commissioning. One of the main reasons is that the irradiation damage to electrode surface, caused by beam losses, influences RF performance of RFQ cavity. This is especially serious for high-current RFQ. By simulation and irradiation experiments, proton irradiation damage to copper target has been studied. The simulation results showed that normally incident proton beams with input energy lower than 1 MeV damage the copper surface in the range of one skin depth at 162.5 MHz, which indicated that almost all the lost beams with small incident angles impact RF performance of RFQ cavity. By the irradiation experiments, the damage within 60 nm depth from surface was proved to have a greater impact on surface finish. The conclusion is that low energy beam losses also need to be kept as low as possible to prolong the life of the RFQ electrodes, especially in high-current RFQ design.

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TUPVA117

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

rfq, ion, linac, proton

2366

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

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

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TUPVA126

The SPS Beam Dump Facility

target, extraction, proton, experiment

2389

M. Lamont, G. Arduini, M. Battistin, M. Brugger, M. Calviani, F. B. Dos Santos Pedrosa, M.A. Fraser, L. Gatignon, S.S. Gilardoni, B. Goddard, J.L. Grenard, C. Heßler, R. Jacobsson, V. Kain, K. Kershaw, E. Lopez Sola, J.A. Osborne, A. Perillo-Marcone, H. Vincke
CERN, Geneva, Switzerland

The proposed SPS beam dump facility (BDF) is a fixed-target facility foreseen to be situated at the North Area of the SPS. Beam dump in this context implies a target aimed at absorbing the majority of incident protons and containing most of the cascade generated by the primary beam interaction. The aim is a general purpose fixed target facility, which in the initial phase is aimed at the Search for Hidden Particles (SHiP) experiment. Feasibility studies are ongoing at CERN to address the key challenges of the facility. These challenges include: slow resonant extraction from the SPS; a target that has the two-fold objective of producing charged mesons as well as stopping the primary proton beam; and radiation protection considerations related to primary proton beam with a power of around 355 kW. The aim of the project is to complete the key technical feasibility studies in time for the European Strategy for Particle Physics (ESPP) update foreseen in 2020. This is in conjunction with the recommendation by the CERN Research Board to the SHiP experiment to prepare a comprehensive design study as input to the ESPP.

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WEOAA2

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

linac, cryomodule, cryogenics, experiment

2466

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

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

Slides WEOAA2 [7.659 MB]

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WEOBA2

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

electron, emittance, simulation, experiment

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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WEOCA2

Experience of Taiwan Photon Source Commissioning and Operation

vacuum, radiation, injection, booster

2495

Y.-C. Liu, C.H. Chen, J.Y. Chen, M.-S. Chiu, P.J. Chou, S. Fann, C.S. Huang, C.-C. Kuo, T.Y. Lee, C.C. Liang, G.-H. Luo, H.-J. Tsai, F.H. Tseng
NSRRC, Hsinchu, Taiwan

The TPS commissioning period is from August 2014 to March 2016. The experience of phase I [1] (bare lattice 2014.8~2015.3) and phase II [2,3] (SRF and insertion devices 2015.9~2016.3) commissioning is overviewed. Taiwan Photon Source (TPS) started user operation in March 2016. The delivery user time reached 3211 hours. The continuous improvements of integrated accelerator performance are described and future developments are discussed.

Slides WEOCA2 [32.368 MB]

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WEOCB1

HTS Magnets for Accelerator Applications

dipole, target, ion-source, power-supply

2543

K. Hatanaka, M. Fukuda, S. Hara, K. Kamakura, M. Nakao, Y. Yasuda, T. Yorita
RCNP, Osaka, Japan

We have developed HTS magnets using the first generation wires for 15 years. HTS materials have larger temperature margin than LTS materials. Magnets can be operated around 20 K or higher temperature and can be conduction-cooled by cryocoolers. The cooling structure becomes simpler and the cooling power of a cooler is high. We expect to excite HTS magnets by AC or pulsed currents without quenching. After successful performance tests of prototype magnets, we fabricated two magnets for practical use, an air-core cylindrical magnet and a super-ferric dipole magnet. The former one is used to polarize ultra-cold neutrons and the latter is a switching dipole magnet to deliver accelerated beams to two target stations by time sharing. Their design and operational performance are presented

Slides WEOCB1 [2.946 MB]

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WEOCB2

Superconducting Magnets at FAIR

dipole, quadrupole, superconducting-magnet, ion

2546

E.S. Fischer, A. Bleile, J. Ceballos Velasco, V.I. Datskov, F. Kaether, J.P. Meier, A. Mierau, H. Müller, C. Roux, P.J. Spiller, K. Sugita
GSI, Darmstadt, Germany

For the FAIR (Facility of Antiproton and Ion Research) accelerators, various technologies of superconducting magnets have been developed. In total, 613 superconducting magnets are required for the FAIR modularized start version. For the heavy ion synchrotron SIS100, which is the central accelerator under construction, fast ramped, iron dominated superconducting magnets of the Nuclotron type will be used. Due to the high beam intensity operation desired for SIS100, highest precision and reproducibility is requested for the iron yoke of these magnets. For the dipole magnets of SIS100 the series production has already been released. In parallel, the Super-FRS will be built for the generation of radioactive beams and for isotope separation. Huge aperture superconducting dipole magnets and multiplet modules are required for the main separator of the Super-FRS. For testing of the various types of sc magnets, three test facilities at GSI, JINR and CERN have been set-up. We give an overview on the modern design aspects for the different magnet types and their first test results and the preparation of the appropriate test facilities.

Slides WEOCB2 [12.633 MB]

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WEPAB001

Parallel Operation of SASE1 and SASE3 Undulator Sections of European XFEL

radiation, undulator, simulation, kicker

2554

A. Sargsyan, V. Sahakyan
CANDLE SRI, Yerevan, Armenia
W. Decking
DESY, Hamburg, Germany

In the current paper the numerical simulation results for parallel (decoupled) operation of SASE1 and SASE3 undulator sections of European XFEL are presented. The study was based on the idea of betatron switcher imple-mentation. It was shown that it is possible to avoid energy spread growth in SASE1 and to reach the saturation in SASE3 in desirable range of radiation wavelengths by a trajectory kick before SASE1 and its correction before SASE3.

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WEPAB003

The Danish Synchrotron Radiation Light Source ASTRID2

quadrupole, cavity, synchrotron, dipole

2561

J.S. Nielsen, N. Hertel, S.P. Møller
ISA, Aarhus, Denmark

The ASTRID2 synchrotron light source has now been in user operation for more than 3 years, and most of the initially unresolved minor issues have been dealt with. This paper will report on the solutions, and give an over-view of the current status. The problem of the fast injection bumpers, which overheated at high currents, has been solved. The 3rd harmonic Landau cavity has been installed, and it has resulted in a much better lifetime and a more stable beam. We observe vertically unstable beams above a given threshold beam current. Initially this threshold was quite low, but with time, as the vacuum chambers have been conditioned more and more, the threshold has increased steadily, and is now close to the design current of 200 mA. It is planned to add 3 more power supplies to each of the pole-face windings, which are found in all 12 dipoles. These three supplies will in addition to the original quadrupole correctors give a vertical corrector, a horizontal corrector and a skew quadrupole corrector. Furthermore we are presently producing a new timing system, which will allow us to run single-bunch operation, and a fast orbit feedback system.

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WEPAB004

Progress Status for the 10 Year Old SOLEIL Synchrotron Radiation Facility

injection, storage-ring, booster, undulator

2564

L.S. Nadolski, Y.-M. Abiven, P. Brunelle, A. Buteau, N. Béchu, M.-E. Couprie, X. Delétoille, J.M. Dubuisson, C. Herbeaux, N. Hubert, M. Labat, J.-F. Lamarre, P. Lebasque, A. Lestrade, A. Loulergue, M. Louvet, P. Marchand, O. Marcouillé, F. Marteau, A. Nadji, R. Nagaoka, F. Ribeiro, K.T. Tavakoli, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

Synchrotron SOLEIL has just turned 10 years since its commissioning. The 2.75 GeV facility is now delivering very stable photon beams to 29 beam lines. A total of 5 operation modes are available in top-up. Maintaining and updating the key performance metric remains a daily work facing both aging of components and tighter operation requirements. Low-alpha operation is attracting more beam lines leading us to an upgrade of the Booster (BOO) radiofrequency (RF) system in order to increase the injection efficiency into the storage ring (SR). The femtoslicing experiment is now in production for a hard X-ray beam line; a dedicated chicane has been installed for a second beam line in the soft X-ray regime. The two long canted beam lines can operate simultaneously at minimum gaps since May 2016 thanks to the introduction of a dedicated photon absorber and a fast angle interlock. R&D work in several areas will be reported. In parallel lattice design are in progress both for short term and long term evolution of the ring performance.

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WEPAB007

Pseudo Single Bunch Qualities Added to Short Pulse Operation of BESSY II

experiment, synchrotron, timing, radiation

2574

R. Müller, T. Birke, F. Falkenstern, K. Holldack, A. Jankowiak, M. Ries, A. Schälicke
HZB, Berlin, Germany

Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of Helmholtz Association
BESSY II features sophisticated filling patterns as well as manipulation and separation techniques of custom bunches to serve both timing and photon hungry experiments at the same time*. Recently, the low alpha operation mode, providing bunch lengths as short as 2 ps, was extended by pseudo single bunch options. A robust technique to excite one bunch with constant displacement and enlargement was implemented for pulse picking by resonant excitation (PPRE)** users. In addition, reliable scraping of an isolated bunch to provide zero current bunch length is opening new timing opportunities. The simultaneous usage of different photon characteristics: high intensity CSR, non-bursting CSR, short duration as well as operation mode specific X-rays impose new challenges. Sensitive tune measurements and feedback mechanisms had to be developed for all three dimensions. Negative alpha is in consideration to overcome the top up efficiency constraints.
*R. Müller et.al. BESSY II Supports an Extensive Suite of Timing Experiments, IPAC16
**K. Holldack et.al. Single bunch X-ray pulses on demand from a multi-bunch SR source, Nature Comm.5, 2014

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WEPAB014

PETRA III Operation

photon, timing, experiment, optics

2589

M. Bieler, I.V. Agapov, H. Ehrlichmann, J. Keil, G.K. Sahoo, R. Wanzenberg
DESY, Hamburg, Germany

At DESY the Synchrotron Light Source PETRA III offers scientists outstanding opportunities for experiments with hard X-rays of exceptionally high brilliance since 2009. This paper describes the challenges of daily operation, including different bunch patterns and their side effects, a procedure to clear spurious bunches, the operational statistics and the main contributions to down time.

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WEPAB015

Parameter Optimization for Operation of sFLASH With Echo-Enabled Harmonic Generation

FEL, laser, electron, bunching

2592

J. Bödewadt, R.W. Aßmann, C. Lechner
DESY, Hamburg, Germany
W. Hillert, T. Plath, J. Roßbach
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
S. Khan, N.M. Lockmann
DELTA, Dortmund, Germany

The free-electron laser facility FLASH has a dedicated experimental setup for external FEL seeding applications for the XUV and soft x-ray spectral range. Recently the setup is operated as high-gain harmonic generation FEL. Furthermore, it also allows the operation of echo-enabled harmonic generation (EEHG). A versatile laser injection system allows operation with seed wavelength in the infra-red, visible, and ultra-violet. Here, we present the parameter optimization for operating the seeding setup with EEHG. First experimental tests are planned in the first half of 2017.

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WEPAB017

Generation of Ultra-Short Electron Bunches and FEL Pulses and Characterization of Their Longitudinal Properties at FLASH2

electron, FEL, laser, undulator

2600

F. Christie, J. Rönsch-Schulenburg, S. Schreiber, M. Vogt
DESY, Hamburg, Germany

The free-electron laser in Hamburg (FLASH) is a user facility, delivering soft X-ray radiation, consisting of two beam lines, FLASH1 and FLASH2. The injector and the main linac are shared between both beam lines. Starting in 2014, FLASH2 has been commissioned for user operation. Currently, there is no hardware installed for the direct measurement of the electron bunch length nor the photon pulse duration at FLASH2. Exact knowledge of the pulse duration is essential for time-resolved user experiments performed at FLASH. Therefore, we are designing a modified beam line, containing a new type of X-band deflecting cavity* and a dipole, downstream of the FLASH2 undulator, to map the longitudinal phase space onto a beam screen. Anticipating the feasibility of measuring the longitudinal phase space with high resolution, a study on optimizing the free-electron laser (FEL) performance for shortest bunches is ongoing.
*B. Marchetti et al., X-Band TDS project, contribution to these conference proceedings

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WEPAB021

Experience with Multi-Beam and Multi-Beamline FEL-Operation

laser, undulator, experiment, FEL

2615

J. Rönsch-Schulenburg, B. Faatz, K. Honkavaara, M. Kuhlmann, S. Schreiber, R. Treusch, M. Vogt
DESY, Hamburg, Germany

DESY's free-electron laser FLASH provides soft X-ray pulses for scientific users at wavelengths down to 4 nm simultaneously in two undulator beamlines. They are driven by a common linear superconducting accelerator with a beam energy of up to 1.25 GeV. The superconducting technology allows the acceleration of electron bunch trains of several hundred bunches with a spacing of 1 microsecond or more and a repetition rate of 10 Hz. A fast kicker-septum system directs one part of the bunch train to FLASH1 and the other part to FLASH2 keeping the full 10 Hz repetition rate for both. The unique setup of FLASH allows independent FEL pulse parameters for both beamlines. In April 2016, simultaneous operation of FLASH1 and FLASH2 for external users started. This paper reports on our operating experience with this type of multi-beam, multi-beamline set-up.

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WEPAB023

First Operation of a Harmonic Lasing Self-Seeded FEL

FEL, undulator, electron, brightness

2621

E. Schneidmiller, B. Faatz, M. Kuhlmann, J. Rönsch-Schulenburg, S. Schreiber, M. Tischer, M.V. Yurkov
DESY, Hamburg, Germany

Harmonic lasing is a perspective mode of operation of X-ray FEL user facilities that allows to provide brilliant beams of higher energy photons for user experiments. Another useful application of harmonic lasing is so called Harmonic Lasing Self-Seeded Free Electron Laser (HLSS FEL) that allows to improve spectral brightness of these facilities. In the past, harmonic lasing has been demonstrated in the FEL oscillators in infrared and visible wavelength ranges, but not in high-gain FELs and not at short wavelengths. In this paper we report on the first evidence of the harmonic lasing and the first operation of the HLSS FEL at the soft X-ray FEL user facility FLASH in the wavelength range between 4.5 nm and 15 nm. Spectral brightness was improved in comparison with Self-Amplified Spontaneous emission (SASE) FEL by a factor of six in the exponential gain regime. A better performance of HLSS FEL with respect to SASE FEL in the post-saturation regime with a tapered undulator was observed as well. The first demonstration of harmonic lasing in a high-gain FEL and at a short wavelength paves the way for a variety of applications of this new operation mode in X-ray FELs.

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WEPAB025

Status of the Soft X-Ray Free Electron Laser FLASH

laser, FEL, photon, experiment

2628

M. Vogt, B. Faatz, K. Honkavaara, M. Kuhlmann, J. Rönsch-Schulenburg, S. Schreiber, R. Treusch
DESY, Hamburg, Germany

The superconducting free-electron laser user facility FLASH at DESY in Hamburg, routinely produces several thousand photon pulses per second. The operational parameters cover a wavelength range from 90 nm down to 4 nm with pulse energies from several uJ up to 1 mJ and with pulse durations of several hundred fs down to a few fs. The FLASH injector and linac drives two undulator beam lines (FLASH1, FLASH2) and therefore FLASH is capable of serving 2 independent experiments with photon pulse (sub-) trains of several 100 bunches at the full train repetition frequency of 10 Hz. We summarize here the highlights of the user operation at FLASH1/2 and the study program (machine development and FEL optimization) of the FLASH facility.

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WEPAB027

Frequency Doubler and Two-color Mode of Operation at Free Electron Laser FLASH2

undulator, radiation, electron, FEL

2635

M. Kuhlmann, E. Schneidmiller, M.V. Yurkov
DESY, Hamburg, Germany

We report on the results of the first operation of a frequency doubler at free electron laser FLASH2. The scheme uses the feature of the variable gap undulator. Undulator is divided in two parts. The second part of the undulator is tuned to the double frequency of the first part. Amplification process in the first undulator part is stopped at the onset of the nonlinear regime, such that nonlinear higher harmonic bunching in the electron beam density becomes pronouncing, but the radiation level is still small to disturb the electron beam significantly. Modulated electron beam enters the second part of the undulator and generates radiation at the 2nd harmonic. Frequency doubler allows operation in a two-color mode and operation at shorter wavelengths with respect to standard SASE scheme. Tuning of the electron beam trajectory, phase shifters and compression allows to tune intensities of the first and the second harmonic. The shortest wavelength of 3.1 nm (photon energy 400 eV) has been achieved with frequency doubler scheme, which is significantly below the design value for the standard SASE option.

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WEPAB035

Elettra Status Present Upgrades and Plans

undulator, controls, photon, storage-ring

2657

E. Karantzoulis, A. Carniel, M. Cautero, B. Diviacco, S. Krecic, R. Visintini
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The operational status of the Italian 2.4/2.0 GeV third generation light source Elettra is presented together with an account of some present upgrades and plans for the near future.

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WEPAB044

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

injection, linac, beam-transport, vacuum

2678

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

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

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WEPAB045

Development of Dedicated Linac and Booster for KEK PF

booster, linac, lattice, injection

2681

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

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

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WEPAB048

Present Status of Accelerators in Aichi Synchrotron Radiation Center

synchrotron, radiation, synchrotron-radiation, storage-ring

2691

M. Hosaka, T. Ishida, A. Mano, A. Mochihashi, Y. Takashima
Nagoya University, Nagoya, Japan
Y. Hori, N. Yamamoto
KEK, Ibaraki, Japan
M. Katoh
UVSOR, Okazaki, Japan
S. Koda
SAGA, Tosu, Japan
H. Ohkuma, S. Sasaki
JASRI/SPring-8, Hyogo-ken, Japan

Aichi Synchrotron Radiation Center is a synchrotron radiation facility in operation since 2013. The electron energy of the storage ring is 1.2 GeV and the circumference is 72 m. In spite of the compact size of the storage ring, synchrotron radiation up to hard X-ray region (~20 keV) is available from the 5 T super conducting bending magnets. Presently (Dec. 2016), 8 beamlines (5 hard X-ray and 3 soft X-ray) are in operation and 2 new hard X-ray beamlines are under commissioning. This contribution reports on the present status as well as machine studies to improve the performance of the accelerators.

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WEPAB064

Upgrade Project on Top-Off Operation for Hefei Light Source

injection, radiation, storage-ring, controls

2719

W. Xu, D. Jia, S.P. Jiang, C. Li, J.Y. Li, J.G. Wang, K. Xuan, Y.L. Yang, Q.B. Zeng, X. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Hefei Light Source has successfully finished a major upgrade project and has been officially opened to users since January 2015. The upgrade project mainly includes increasing the linac injector energy from 200 MeV to 800 MeV which is the same as the ring energy, changing the ring lattice structure from TBA to DBA in order to provide more straight sections for insertion devices while keeping the circumference unchanged, and lowering the beam emittance to obtain higher photon brightness. Before the upgrade project, decay mode is the only choice for the operation of Hefei Light Source. This is because the injected beam from the linac injector needs to be ramped up to 800 MeV after injection. At prensent we have the conditions to operate Hefei Light Source with top-off mode since the linac can perform full-energy and bunch-by-bunch injection. The main challenge for the top-off operation is to control the radiation dose for personal and equipment safety, and to maintain high stability and reliability of the injector. In this paper, we report our work on the top-off operation project for Hefei Light Source.

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WEPAB071

Single Bunch Bucket Selection Injection Modes in the ALBA Storage Ring

injection, linac, storage-ring, electron

2744

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

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

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WEPAB085

Siam Photon Source: Present Machine Status and Future Upgrades

storage-ring, injection, electron, photon

2770

P. Klysubun, S. Boonsuya, N. Juntong, K. Kittimanapun, S. Kongtawong, S. Krainara, A. Kwankasem, T. Pulampong, P. Sudmuang, N. Suradet
SLRI, Nakhon Ratchasima, Thailand

Siam Photon Source, the Thailand synchrotron light source, has received several upgrades in recent years. Most important of which are the improvement of the positional stability of the stored electron beam, and the installation of 2 IDs, i.e. a 2.2 T hybrid multipole wiggler and a 6.5 T superconducting wavelength shifter, to extend the available SR spectrum into hard x-ray region. The beam stability improvement was achieved through several activities, including improving the BPM system, upgrading the existing corrector power supplies, and implementing global orbit feedback. The two new IDs provide higher-intensity and higher-energy (up to 25 keV) synchrotron light, which will be utilized for MX, high-energy SAXS, WAXS, XAS, and microtomography. Ongoing machine upgrades include increasing the energy of the booster and transport line to 1.2 GeV for full-energy injection and eventual top-up operation. Utilization of the electron beam is also being explored. A beam test facility, which extracts electron beam in the booster for characterizing high-energy particle sensors, as well as calibrating other beam diagnostic instruments, has been constructed and is now in operation.

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WEPAB094

Diamond: Ten Years of Operation

cavity, vacuum, storage-ring, controls

2797

V.C. Kempson
DLS, Oxfordshire, United Kingdom

In January 2017 Diamond Light Source reached ten years of operation, providing beam to beam lines and users. At the start of operations there was an initial suite of 7 beam lines, phase 1. We are now in the later part of a phase 3 beam line upgrade bringing the total number of beam lines up to 29+ which is close to maximum capacity. The 3GeV storage ring has had a number of modifications and improvements across the last 10 years culminating in the recent (Autumn 2016) addition of a major local lattice modification, DDBA , reported elsewhere at this conference. This review paper will look at machine improvements operationally and machine developments that improved overall performance.

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WEPAB096

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

cavity, vacuum, feedback, emittance

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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WEPAB098

Dielectrically-Loaded Waveguide as a Microwave Undulator for High Brillance X-Rays at 45 - 90 Kev

undulator, brightness, photon, coupling

2812

R. Kustom, A. Nassiri, G.J. Waldschmidt
ANL, Argonne, Illinois, USA

The HEM12 mode in a cylindrical, dielectrically-loaded waveguide provides E and H fields on the central axis that are significantly higher than the fields on the conducting walls. This structure, operating near the cutoff frequency of the HEM12 mode, spans a frequency range where the wavelength and phase velocity vary significantly. This property can be exploited to generate undulator action with short periods for the generation of high brightness x-rays. The frequency range of interest would be from 18 to 34.5-GHz. The goal would be to generate x-rays on the fundamental mode over a range of 45 to 90-kev. The tunability would be achieved by changing the source frequency while maintaining a constant on-axis equivalent undulator field strength of 0.5-T.

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WEPAB099

Development of the Manufacturing and QA Processes for the LCLS-II Injector Source VHF Electron Gun

gun, site, electron, cavity

2815

J.A. Doyle, J.N. Corlett, M.J. Johnson, R. Kraft, T.D. Kramasz, D. Leitner, S.P. Virostek
LBNL, Berkeley, California, USA

Funding: * This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
The Linear Coherent Light Source-II (LCLS-II), a new free electron laser currently under construction at SLAC, requires a high repetition rate, high brightness, continuous wave electron source. Lawrence Berkeley National Laboratory (LBNL) has developed a design for a normal conducting VHF gun in response to that need and is responsible for its production and that of the associated beamline, with much of the fabrication done in-house. The 186 MHz copper cavity dissipates approximately 90 kW of RF power while maintaining a vacuum pressure on the order of 10^-10 Torr. The gun is a critical component that requires a very high level of operational reliability to ensure uninterrupted availability for future system users. A quality assurance system to instruct manufacturing and change control is vital to ensure production of a gun that reliably meets physics requirements over an extended period of usage. This paper describes the QA processes developed for fabrication and assembly of the Injector Source electron gun along with results and lessons learned from their current implementation.

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WEPAB101

Lattice Optimization Using Jupyter Notebook on HPC Clusters

Linux, lattice, software, Windows

2818

H. Nishimura, K.M. Fernsler, S. James, G.M. Jung, Y. Qin, K. Song, C. Sun
LBNL, Berkeley, California, USA

Funding: Work supported by the Director Office of Science of the U. S. Department of Energy under Contract No. DE-AC02-05CH11231
Tracy accelerator simulation library was originally developed for the Advanced Light Source (ALS) design studies at LBNL in the late 1980's. It was originally written in Pascal, later ported to C++, and then to C#. It is still actively updated and currently used by the ALS Upgrade Project (ALS-U) to design and to optimize the lattice. Recently, it has been reconstructed to provide ease of use and flexibility by leveraging the quickly growing Python language. This paper describes our effort of porting it to Jupyter Notebook on our institutional High-Performance Computing (HPC) clusters.

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WEPAB120

Reproducibility Issues of NSLS-II Storage Ring and Modeling of the Lattice

lattice, quadrupole, storage-ring, dipole

2851

J. Choi, W. Guo, T.V. Shaftan, X. Yang
BNL, Upton, Long Island, New York, USA

Funding: DOE Contract No: DE-SC0012704
As other facilities, in operating NSLS-II, we develop the lattices based on theoretical and simulation studies. Then the lattice is applied and the machine is optimized to have the desired design parameters. This process is very typical and works well and, furthermore, there is a general understanding that a model with the field measurement data is not realized as it is. However, it is evident that if the model represents the real machine close enough, there are lots of advantages we can take. One of them can be producing the lattice with changing environments. In this paper, we discuss the NSLS-II reproducibility status and efforts to construct the faithful realistic model.

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WEPAB121

Database for NSLS-II Accelerator Operation

database, interface, controls, software

2854

J. Choi, R.I. Farnsworth, T.V. Shaftan, G.J. Weiner, X. Yang
BNL, Upton, Long Island, New York, USA

Funding: DOE Contract No: DE-SC0012704
NSLS-II is employing a database and corresponding user interfaces which are used for the accelerator data sharing and management. The database include operation related information such as beam optics parameters, magnet measurement data, survey data and operation summary. To improve the usability, other functionalities are also being added. However, due to the limited scope, the general expectation of the overall facility cannot not be met and, in order to solve the issue, we are in the process of adopting Component Database (ComponentDB) developed at Advanced Photon Source (APS). This paper shows the current status of the process.

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WEPIK010

Commissioning Status of SuperKEKB Main Ring Magnet System

power-supply, dipole, interaction-region, luminosity

2933

M. Masuzawa, T. Adachi, K. Egawa, T. Kawamoto, S. Nakamura, Y. Ohsawa, T. Oki, R. Sugahara, R. Ueki
KEK, Ibaraki, Japan

SuperKEKB is an electron-positron collider, which aims for the very high peak luminosity of 8x10³⁵ cm^-2s^-1 , 40 times higher than that of KEKB. The SuperKEKB Main Ring (MR) system is very large, consisting of more than 1700 water-cooled normal-conducting magnets and about 900 air-cooled normal-conducting magnets. More than 400 magnets and power supplies were newly fabricated, tested and installed for SuperKEKB Phase I beam operation. The MR magnet system worked well, which contributed greatly to the smooth start-up of the MR. Commissioning status of the MR magnet system during SuperKEKB Phase I operation will be reported. Some problems resulting in beam abort will also be reported.

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WEPIK011

Ceramic Chamber Used in SuperKEKB High Energy Ring Beam Abort System

kicker, vacuum, target, injection

2936

T. Mimashi, N. Iida, M. Kikuchi, K. Kodama, T. Mori
KEK, Ibaraki, Japan
K. Abe
Hitachi Power Semiconductor Device, Ltd., Hitachishi, Ibaraki, Japan

The water-cooled type ceramic chambers were used for Super-KEKB high energy ring beam abort system. Since the horizontal abort kicker magnets are required to have very fast rise time and large current, the gap of kicker magnet must be as small as possible. The thin and compact ceramic chamber were developed. The chamber has racetrack type chamber whose inner diameter is 60mm in horizontal and 40 mm in vertical. And the gap of horizontal kicker magnet is 70mm. The thickness of the ceramic chamber is 30 % reduced from that of KEKB. The 500mm long hollow type ceramic, which includes cooling water path inside, is fabricated. It makes the structure of ceramic chamber simple and compact. The new copper electroforming is applied to deposit the 100μmeter thickness Cu conducting layer on the inner wall of Kovar. The Cu conducting layer reduces the heat generated by image beam current on the Kovar brazering. They are installed in the Super-KEKB electron ring beam abort system, and used in the phase 1 operation. The paper describes the performance of the water-cooled ceramic chamber under phase 1 operation.

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WEPIK012

Performance of SuperKEKB High Energy Ring Beam Abort System

kicker, extraction, sextupole, power-supply

2939

T. Mimashi, Y. Enomoto, N. Iida, M. Kikuchi, K. Kodama, T. Mori, Y. Suetsugu
KEK, Ibaraki, Japan
K. Abe
Hitachi Power Semiconductor Device, Ltd., Hitachishi, Ibaraki, Japan
K. Kise, A. Tokuchi
Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan

New Beam abort system was installed at the Super-KEKB High Energy Ring. It was designed to enlarge the horizontal beam size at the beam extraction window to protect the extraction window, and it also makes the beam abort gap shorter. It consists of four horizontal kicker magnets, one vertical kicker to sweep the beam position in vertical direction, sextupole magnet to enlarge the horizontal beam size, one lambertson magnet, Ti extraction window and beam dump. Four horizontal kicker magnets and one vertical kicker magnet connects to the one power supply. The ceramic chambers cooled by the water are inserted in each kicker coils. The Abort system had been used during SuperKEKB phase 1 operation. This paper describes the performance of the abort system.

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WEPIK026

VEPP-5 Injection Complex: Two Colliders Operation Experience

injection, collider, extraction, positron

2982

D.E. Berkaev, A.V. Andrianov, K.V. Astrelina, V.V. Balakin, A.M. Batrakov, O.V. Belikov, M.F. Blinov, D. Bolkhovityanov, A. Butakov, E.V. Bykov, N.S. Dikansky, F.A. Emanov, A.R. Frolov, V.V. Gambaryan, K. Gorchakov, Ye.A. Gusev, S.E. Karnaev, G.V. Karpov, A.S. Kasaev, E. Kenzhebulatov, V.A. Kiselev, S. Kluschev, A.A. Kondakov, I. Koop, I.E. Korenev, N.Kh. Kot, V.R. Kozak, A.A. Krasnov, S.A. Krutikhin, I.V. Kuptsov, G.Y. Kurkin, N.N. Lebedev, A.E. Levichev, P.V. Logatchov, Yu. Maltseva, A.A. Murasev, V. Muslivets, D.A. Nikiforov, An.A. Novikov, A.V. Ottmar, A.V. Pavlenko, I.L. Pivovarov, V.V. Rashchenko, Yu. A. Rogovsky, S.L. Samoylov, N. Sazonov, A.V. Semenov, S.V. Shiyankov, D.B. Shwartz, A.N. Skrinsky, A.A. Starostenko, D.A. Starostenko, A.G. Tribendis, A.S. Tsyganov, S.S. Vasichev, S.V. Vasiliev, V.D. Yudin, I.M. Zemlyansky, A.N. Zhuravlev
BINP SB RAS, Novosibirsk, Russia
A.V. Andrianov, V.V. Balakin, F.A. Emanov, I. Koop, A.A. Krasnov, A.E. Levichev, D.A. Nikiforov, A.V. Pavlenko, Yu. A. Rogovsky, D.B. Shwartz, A.A. Starostenko
NSU, Novosibirsk, Russia
A.I. Mickailov
Budker INP & NSU, Novosibirsk, Russia
A.G. Tribendis
NSTU, Novosibirsk, Russia

Two BINP colliders VEPP-4M and VEPP-2000 e⁺e⁻ colliders are under operation with the beams feeding from VEPP-5 Injection Complex via newly constructed K-500 beam transfer line. Upgraded injection chain demonstrated ability to provide designed luminosity both to VEPP-4M and VEPP-2000 and techniques of reliable operation are under development now. The design and operation experience of Injection Complex and transfer lines are presented.

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WEPIK033

LHC Beam Dump Performance in View of the High Luminosity Upgrade

kicker, extraction, proton, hardware

2999

C. Wiesner, W. Bartmann, C. Bracco, E. Carlier, L. Ducimetière, M.I. Frankl, M.A. Fraser, B. Goddard, T. Kramer, A. Lechner, N. Magnin, S. Mazzoni, M. Meddahi, V. Senaj
CERN, Geneva, Switzerland

The High Luminosity Large Hadron Collider (HL-LHC) project will increase the total beam intensity in the LHC by nearly a factor of two. Analysis and follow-up of recent operational issues as well as dedicated studies of the LHC Beam Dump System (LBDS) have been carried out to ensure the safe operation with HL-LHC parameters and to decide on possible hardware upgrades to meet the HL-LHC requirements. The fail-safe design must ensure the LBDS performance also for abnormal operation such as asynchronous beam dumps or failing dilution kickers. In this paper, we report on newly observed failure scenarios as the erratic firing of more than one dilution kicker, and discuss their consequences as well as possible mitigation measures in view of the high luminosity upgrade.

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WEPIK036

ERL Cryomodule Testing and Beam Capabilities

cavity, linac, cryomodule, SRF

3010

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

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

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WEPIK056

Compensation of Transient Beam Loading with Detuned Cavities at BESSY II

cavity, experiment, beam-loading, synchrotron

3056

M. Ruprecht, P. Goslawski, F. Kramer, M. Ries
HZB, Berlin, Germany

This paper presents operational experience and use cases of cavity operation in the synchrotron light source BESSY II, where an active or passive cavity is detuned by a small fraction of the harmonic number. If the detuning is an integer multiple of the fundamental RF harmonic, the distortion of the longitudinal phase space is periodic with the revolution, which allows for the compensation of fill pattern induced transients. Measurements at BESSY II are presented, where a fundamental cavity is detuned to decrease the effects of transient beam loading. Thus, reducing the phase transient and increasing the beam life time. Calculations depicting the application of this scheme for the future project BESSY VSR[*] are presented.
* A. Jankowiak, J. Knobloch, P. Goslawski, and N. Neumann, eds., BESSY VSR - Technical Design Study, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 2015.

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WEPIK057

Transverse Resonance Island Buckets as Bunch Separation Scheme

injection, optics, simulation, sextupole

3059

P. Goslawski, A. Jankowiak, F. Kramer, M. Ries, M. Ruprecht, G. Wüstefeld
HZB, Berlin, Germany

Funding: Supported by the BMBF
Beam storage close to a tune resonance (Qx = 1/3,1/4) can generate transverse resonance island buckets in the x,x' phase space providing a second stable island orbit winding around the standard orbit. The two orbits are well separated, with good life time and stability. Successful user experiments have been conducted at BESSY II and the Metrology Light Source (MLS) *,** with such an operation mode. We discuss the required beam optics setup, the TopUp injection process and present successful measurements taken at photon beamlines at BESSY II.
* THPMR017, P.Goslawski et al., IPAC2016, Busan, Korea
** MOPWA021, M.Ries et al., IPAC2015, Richmond, USA

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WEPIK068

Non-Linear Beam Dynamics Studies of the CLIC Damping Wiggler Prototype

wiggler, optics, storage-ring, damping

3087

J. Gethmann, A. Bernhard, E. Blomley, E. Huttel, A.-S. Müller, A.I. Papash, M. Schedler
KIT, Karlsruhe, Germany
Y. Papaphilippou, P. Zisopoulos
CERN, Geneva, Switzerland
K. Zolotarev
BINP SB RAS, Novosibirsk, Russia

Funding: Julian Gethmann acknowledges the support by the DFG-funded Doctoral School Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology
First beam dynamics studies of a damping wiggler prototype for the CLIC damping rings have been carried out at the KIT storage ring. Effects of the 2.9 T superconducting wiggler on the electron beam in the 2.5 GeV standard operation mode have been measured and compared with theoretical predictions. Higher order multipole components were investigated using local orbit bump measurements. Based on these findings the simulation models for the storage ring optic have been adjusted. The refined optics model has been applied to the 1.3 GeV, low-operation case. This case will be used to experimentally benchmark beam dynamics simulations involving strong wiggler fields and dominant collective effects. We present these measurements, comparisons and the findings of the simulations with the updated low-mode optics model.

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WEPIK098

Resonant Kicker System With Sub-part-per-million Amplitude Stability

kicker, electron, resonance, dipole

3174

M. Paraliev, C.H. Gough
PSI, Villigen PSI, Switzerland

High stability resonant kicker magnet systems have been developed as part of the fast electron beam switching system of Swiss Free Electron Laser (SwissFEL). They are designed to separate two closely spaced electron bunches (28 ns apart) accelerated in one RF macro-pulse and to send them to two separate undulator lines. High shot-to-shot amplitude stability is required to minimize the disturbance of the electron beam trajectories and to ensure stable X-ray lasing. The stability and speed was unlikely to be achieved by standard pulsed systems and a novel 18 MHz, lumped-element resonator deflector with high Q was developed. It is driven into resonance by a specialized pulsed RF driver. At resonance, the circulating currents can approach 300 A and the resulting magnetic field gives the required deflection to the electron bunches. The advanced DC offset measurement system is also described in this paper. The measured stability reached less than 1 ppm (10e-6) rms, well within the project requirements.

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WEPIK099

Beam Lifetime Studies for SPS Storage Ring

storage-ring, insertion-device, insertion, simulation

3178

P. Sudmuang, N. Juntong, P. Klysubun, T. Pulampong, N. Suradet
SLRI, Nakhon Ratchasima, Thailand

Limitation of beam lifetime was systematically investigated and studied for Siam Photon Source (SPS) storage ring. The objective was to identify the main cause of the observed reduction of beam lifetime. The simulations of momentum acceptance and Touschek lifetime were performed, incorporating non-linear effects generated by the installed high-field insertion devices. The Touschek lifetime was measured as a function of RF voltage and compared with the values obtained from simulation. The measurements were performed for a variety of different operation conditions of the insertion devices and different chromaticities.

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WEPIK111

Derivation of a Finite Element Formulation From a Lagrangian for the Electromagnetic Potentials

electromagnetic-fields, coupling, resonance, interface

3208

A.R. Vrielink, M.H. Nasr, S.G. Tantawi
SLAC, Menlo Park, California, USA

Conventional electromagnetic finite element solvers typically solve a weak formulation of the Helmholtz wave equation. While mathematically this approach is correct, it does not fully reflect the fundamental physics involved. We offer an alternative variational formulation which is not derived from the Helmholtz wave equation but is more fundamentally tied to the physics of the system: a Lagrangian for the electromagnetic potentials. Solving for the potentials directly allows for a natural accounting of the beam wave interaction. It could also potentially avoid the issue of deleterious spurious modes inherent when selecting the Coulomb gauge and enforcing the subsequent divergence free condition, eliminating the need for vector basis functions. Herein we present the theory and the resulting formulation including a discussion on gauge fixing. We conclude with some numerical results demonstrating the potential of this formulation.

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WEPIK112

A 2D Finite Element Solver for Electromagnetic Fields with m-fold Azimuthal Symmetry

simulation, interface, gun, cavity

3211

A.R. Vrielink, M.H. Nasr, S.G. Tantawi
SLAC, Menlo Park, California, USA

Radiofrequency (RF) cavities for use in accelerators, from RF sources to accelerating and transverse cavities, often exhibit m-fold azimuthal symmetry. For cases where m>0, commercially available finite element codes used to simulate the beam-wave interaction typically require a full 3D simulation. We have derived a finite element formulation which accounts for the known azimuthal dependence of the electromagnetic fields, allowing us to solve for these problems on a 2D mesh and reducing simulation times significantly. The theory, including the construction of the local finite element matrices and the selection of appropriate basis functions, will be presented in addition to numerical results.

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WEPIK118

Synchronous Phase Shift from Beam Loading Analysis

beam-loading, cavity, storage-ring, resonance

3227

G. Bassi, A. Blednykh, J. Rose, V.V. Smaluk, J. Tagger
BNL, Upton, Long Island, New York, USA

We discuss measurements, performed in the NSLS-II storage ring, of the synchronous phase shift as a function of single bunch current from beam loading parameters. The synchronous phase is calculated from the forward and reflected power measured in the RF cavities. The comparison with direct synchronous phase measurements shows good agreement.

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WEPVA023

Performance of the PS Injection Kicker System Short Circuit Mode Upgrade for Operation with 2 GeV LIU Beams

flattop, kicker, injection, simulation

3308

T. Kramer, W. Bartmann, J.C.C.M. Borburgh, L. Ducimetière, L.M.C. Feliciano, A. Ferrero Colomo, B. Goddard, L. Sermeus
CERN, Geneva, Switzerland

In the framework of the LHC Injector Upgrade (LIU) project an upgrade of the existing PS proton injection kicker system for 2 GeV operation is in progress. The upgrade is based on the operation of the existing kicker system in short circuit mode. This paper briefly reviews the deployed modifications to the system to obtain the specified reduction of pulse reflections unavoidably induced by such a configuration. The implementation of improvements to the magnet entry box, transmission cables and the short circuit plug with integrated LC-filter are described as well as tests and measurements during the 2016/17 annual shutdown. The impact of the residual pulse shape structure on the beam performance for the reference LIU beam is quantified. The paper concludes with a performance analysis, a comparison of measurements vs. simulations and an outlook to the remaining modifications during the next long shut down.

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WEPVA029

SIS100 Tunnel Design and Status

radiation, shielding, site, extraction

3316

C. Omet, J. Falenski, G. Fehrenbacher, H. Kisker, K. Konradt, A. Sokolov, P.J. Spiller
GSI, Darmstadt, Germany
A. Fischer
FAIR, Darmstadt, Germany

As the FAIR project is proceeding, many of the building and tunnel designs in the meanwhile are frozen and documents are prepared for tendering. For the future FAIR driver accelerator, SIS100, the accelerator tunnel T110 comprises a 1100 m long tunnel, which has a depth of 17 m under ground. In this paper, its environmental boundary conditions, design principles and the finally chosen layout are presented.

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WEPVA030

FAIR SIS100 - Features and Status of Realisation

cryogenics, ion, dipole, synchrotron

3320

P.J. Spiller, U. Blell, L.H.J. Bozyk, T. Eisel, E.S. Fischer, J. Henschel, P. Hülsmann, H. Klingbeil, H.G. König, H. Kollmus, P. Kowina, J.P. Meier, A. Mierau, C. Mühle, C. Omet, D. Ondreka, V.P. Plyusnin, I. Pongrac, N. Pyka, P. Rottländer, C. Roux, J. Stadlmann, B. Streicher, St. Wilfert
GSI, Darmstadt, Germany

SIS100 is a unique heavy ion synchrotron designed for the generation of high intensity heavy ion and Proton beams. New features and solutions are implemented to enable operation with low charge state heavy ions and to minimize ionization beam loss driven by collisions with the residual gas. SIS100 aims for new frontier and world wide leading Uranium bam intensities. A huge effort is taken to stabilized the dynamics of the residual gas pressure and to suppress ion induced desorption. Fast ramped superconducting magnets have been developed and are in production with highest precision in engineering and field quality, matching the requirements from beams with high space charge. A powerful equipment with Rf stations for fast acceleration, pre- and final compression, for the generation of barrier buckets and provision of longitudinal feed-back shall allow a flexible handling of the ion bunches for the matching to various user requirements. Results obtained with FOS (first of series) devices, status of realisation and technical challenges resulting from the demanding goals, will be presented.

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WEPVA039

Transition Crossing in the Main Injector for PIP-II

simulation, lattice, booster, emittance

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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WEPVA047

Input Signal Generation for Barrier Bucket RF Systems at GSI

cavity, synchrotron, storage-ring, impedance

3359

J. Harzheim, D. Domont-Yankulova, K. Groß, H. Klingbeil
TEMF, TU Darmstadt, Darmstadt, Germany
M. Frey, H. Klingbeil
GSI, Darmstadt, Germany

At the GSI facility in Darmstadt, Germany, Barrier Bucket RF systems are currently designed for the SIS 100 synchrotron (part of the future FAIR facility) and the Experimental Storage Ring (ESR). The purpose of these systems is to provide single sine voltage pulses at the cavity gap. Due to the high requirements regarding the gap signal quality, the calculation of the pre-distorted input signal plays a major role in the system development. A procedure to generate the input signal based on the dynamic properties in the linear region of the system has been developed and tested at a prototype system. It was shown that this method is able to generate single sine gap signals of high quality in a wide voltage range. As linearity can only be assumed up to a certain magnitude, nonlinear effects limit the quality of the output signal at very high input levels. An approach to overcome this limit is to extend the input signal calculation to a nonlinear model of the system. In this contribution, the current method to calculate the required input signal is presented and experimental results at a prototype system are shown. Additionally, first results in the nonlinear region are presented.

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WEPVA048

Particle Generation of CapaciTorr Pumps

vacuum, detector, SRF, synchrotron

3363

S. Lederer, L. Lilje
DESY, Hamburg, Germany
E. Maccallini, P. Manini, F. Siviero
SAES Getters S.p.A., Lainate, Italy

Non Evaporable Getter pumps have been used since four decades in various scientific and industrial Ultra High and Extremely Ultra High Vacuum applications. For the majority of applications properties like high pumping speed vs. small size, powerless operation and hydrocarbon cleanliness are main aspects for the usage. In addition to this a growing number of applications nowadays also require particle free systems. In this paper we report on investigations on in-vacuum particle creation during the conditioning and activation process of CapaciTorr pumps.

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WEPVA052

The Infrastructure for the Elettra Sincrotrone Trieste

storage-ring, linac, FEL, laser

3375

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

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

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WEPVA056

Development of an Induction Accelerator Cell Driver Utilizing 3.3 kV SiC-MOSFETs

induction, power-supply, ion, synchrotron

3388

K. Okamura, K. Takayama
KEK, Ibaraki, Japan
K. Takayama
Sokendai, Ibaraki, Japan

A novel synchrotron called an induction synchrotron (IS) was developed at KEK in 2006*. In the IS, charged particles are accelerated by pulse voltages driven by switching modulators employing high-speed semiconductor switches. As the switches are turned on and off by gate signals corresponding to the revolution frequency of the ion bunches, switching frequency reaches up to MHz order. The switching power supply (SPS) that generates bipolar pulses is one of the key technologies for the DA. The rating of SPS is roughly 2.5kV-20A-1MHz. To accomplish these requirements, we adopted 7 series connected Si-MOSFET for the switching devices of the 1st generation SPS. However it was too large and complicated for the future practical accelerator driver. Therefore we started to develop the next generation of SPS utilizing silicon carbide (SiC) devices, since they have inherently excellent properties such as high breakdown electric field high drift velocity, and high thermal conductivity**. In this paper, we describe the pulse switching test results of a prototype SiC-MOSFET and the test results of the prototype SPS.
* K. Takayama et al., Phys. Rev. Lett., 98, no.5, pp.054801(1)-054801(4) (2007).
**H. Okumura, Japanese J. Appl. Phys. vol.45, no.10A, pp. 7565-7586, Oct. 2006.

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WEPVA057

High-Stability Magnet Power Supplies for SuperKEKB

controls, feedback, power-supply, wiggler

3391

T. Oki, T. Adachi, S. Nakamura
KEK, Ibaraki, Japan

For the SuperKEKB, over 2,000 of magnet power supplies were recycled and around 300 of power supplies were newly fabricated. The newly fabricated power supplies include high performance power supplies: the main bending/wiggler magnet power supplies and the power supplies for final-focus superconducting magnets installed around an interaction point. High power tests were performed and the results are reported.

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WEPVA061

High-Precision Pattern Power Supply of Kicker Magnet for Multi-Beamline Operation at SACLA

power-supply, kicker, optics, electron

3404

C. Kondo, T. Fukui, T. Hara, T. Inagaki, Y. Otake, H. Tanaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
K. Fukami
JASRI/SPring-8, Hyogo-ken, Japan
H. Kawaguchi, Y. Kawaguchi
Nichicon (Kusatsu) Corporation, Shiga, Japan
S. Nakazawa
SES, Hyogo-pref., Japan

At the Japanese XFEL facility SACLA, two XFEL beamlines (BL2 and BL3) and an injection line to the SPring-8 storage ring are switched by a kicker magnet. This multi-beamline operation has been tested since February 2015, however, CSR effects at a dogleg beam transport to BL2 with a deflecting angle of 3 degree currently limit the peak current of the electron beam. In order to suppress and cancel out the CSR effects, new beam optics is introduced for the dogleg in January 2017. In the new optics, a deflecting angle of the first kicker magnet is increased to 1.5 degree, which is three times larger than that of the old optics. To drive the kicker magnet, a high-power pattern power supply has been developed. To achieve the maximum output of 300 A and 1 kV, SiC MOSFETs are used as switching modules. The newly developed power supply can generate bipolar trapezoidal current waveforms at 60 Hz, and the amplitude and polarity of each waveform are controlled from pulse to pulse according to the beam energy and destination. The target stability is 10 ppm (peak to peak). In this presentation, we report the design and operation results of the newly developed pattern power supply.

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WEPVA062

Improvements of Vacuum System in J-PARC 3 GeV Synchrotron

vacuum, injection, kicker, cavity

3408

J. Kamiya, Y. Hikichi, M. Kinsho, Y. Namekawa, K. Takeishi, T. Yanagibashi
JAEA/J-PARC, Tokai-mura, Japan
A. Sato
Nippon Advanced Technology Co., Ltd., Tokai, Japan

The RCS vacuum system has been upgraded since the completion of its construction towards the objectives of both better vacuum quality and higher reliability of the components. For the better vacuum quality, (1) pressure of the injection beam line was improved to prevent the H⁻ beam from converting to H0; (2) leakage in the beam injection area due to the thermal expansion was eliminated by applying the adequate torque amount for the clamps; (3) new in-situ degassing method of the kicker magnet was developed. For the reliability increase of the components, (1) A considerable number of fluoroelastmer seal was exchanged to metal seal with the low spring constant bellows and the light clamps; (2) TMP controller for the long cable was developed to prevent the controller failure by the severe electrical noise; (3) A number of TMP were installed instead of ion pumps in the RF cavity section as an insurance for the case of pump trouble.

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WEPVA063

Development of a New Pulsed Power Supply with the SiC-MOSFET

power-supply, kicker, flattop, pulsed-power

3412

T. Takayanagi, K. Horino, J. Kamiya, M. Kinsho, T. Ueno, K. Yamamoto
JAEA/J-PARC, Tokai-mura, Japan
Y. Mushibe, A. Tokuchi
Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan

A new power supply has been developed using linear transformer driver (LTD) technology that adopts SiC-MOSFETs and capacitors without a thyratron switch or a pulse forming network (PFN) device. A new power supply was also designed by connecting the SiC-MOSFETs and the LTD modules in parallel-series. The output voltage and current were 40 kV and 4 kA, respectively with a pulse width of 1500 nsec at a repetition rate of 25 Hz. Furthermore, by adjusting the correction module, to an output voltage per stage of 1/1000, a resolution of the voltage correction of ±0.1 % could be achieved. It was possible to output the current with arbitrary timing by using a trigger input for each LTD module. As a result, fine adjustment of the output voltage waveform was possible within the order of nanoseconds. This new power supply with high voltage output, cur-rent output, and very fast pulse operation is one of the most important key technologies for a kicker system using SiC-MOSFETs. The design and preliminary test results of this prototype power supply are presented here.

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WEPVA066

The ESS Target Proton Beam Imaging System as in-Kind Contribution

target, proton, neutron, radiation

3422

E. Adli, R. Andersson, D.M. Bang, O. Dorholt, H. Gjersdal, O. Røhne
University of Oslo, Oslo, Norway
M.G. Ibison, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
S. Joshi
University College West, Trollhätan, Sweden
T.J. Shea, C.A. Thomas
ESS, Lund, Sweden

Funding: This work is part of the Norwegian in-kind contribution to ESS.
The ESS Target Proton Beam Imaging System will image the 5 MW ESS proton beam as it enters the spallation target. The system will operate in a harsh radiation environment, leading to a number of challenges: development of radiation hard photon sources, long aperture-restricted optical paths, and fast electronics to provide rapid response to beam anomalies. The newly formed accelerator group at the University of Oslo is the in-kind partner for the Imaging System. This paper outlines the main challenges of the Imaging System and how they are addressed within the collaborative nature of the in-kind project.

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WEPVA068

Design and Development of Accelerator Magnet Power Supply Based on SiC-MOSFET

power-supply, controls, interface, experiment

3429

L. Yang, F. Long, Z.H. ZhenHua
IHEP, Beijing, People's Republic of China

SiC is a new type of semiconducting material with rapid development after the first generation and the second generation of semiconductor materials represented by silicon and gallium arsenide. SiC-MOSFET has a high frequency, high breakdown voltage, high temperature, radiation and many other points, suitable for future use in the accelerator magnet power supply. In this paper, the development and operation of a SiC-MOSFET-based accelerator magnet power supply are described in detail. The experiment results show that the performance of this power supply is superior to that of the same specification using Si-MOSFET. The power supply adopts one-way AC power supply, and the output stage adopts the full bridge circuit topology. The power device adopts C2M0040120D SiC-MOSFET, the working frequency is 30 kHz, the output current is ± 20A, the output voltage is ± 20V, and power is 400W. The Digital Power Supply Control Module (DPSCM) is used to realize high-precision digital closed-loop control, which supports on-line debugging and PC control. Power supply can be used to correct the magnet power, with high efficiency, high stability, and fast response and so on.

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WEPVA082

Technical Overview of the SOLARIS Low-Conductivity Water Cooling System

synchrotron, storage-ring, linac, klystron

3449

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

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

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WEPVA084

Performance of the PAL-XFEL High Precision Magnet Power Supplies

controls, power-supply, status, site

3452

S.-H. Jeong, J.H. Han, Y.G. Jung, H.-S. Kang, D.E. Kim, H.-G. Lee, S.B. Lee, B.G. Oh, K.-H. Park, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea

In the PAL-XFEL, 632 magnet power supplies (MPS) have been operated since 2016. High current unipolar MPSs(>100A) were configured buck mode with single power stack or two. The corrector MPSs for low current were the H-bridge type for bipolar current driving. The nine different types of MPS were installed for beam dy-namics in the PAL-XFEL machine. All MPSs had been tested and confirmed their performances before installa-tion. We described here the status of the MPS operation after installation on 2016.

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WEPVA096

Thermal Analysis of the LHC Injection Kicker Magnets

injection, kicker, vacuum, simulation

3479

L. Vega Cid, M.J. Barnes, V. Vlachodimitropoulos, W.J.M. Weterings
CERN, Geneva, Switzerland
A. Abánades
ETSII UPM, Madrid, Spain

Funding: Research supported by the HL-LHC project.
The CERN Large Hadron Collider LHC is equipped with two fast pulsed magnet systems (MKIs) that inject particle beams coming from the injector chain. Operation with high intensity beams for many hours can lead to significant beam induced heating of the ferrite yokes of the MKIs. When the ferrite exceeds the Curie temperature of 125°C it loses its magnetic properties, preventing further injection until the ferrite cools down, potentially causing a delay of several hours. Hence important upgrades of the beam-screen were implemented after Run 1 of LHC. However, the High-Luminosity (HL) LHC will be operated with significantly higher intensity beams and hence additional measures are required to limit the ferrite temperature. These magnets operate under ultra-high vacuum conditions: convection is negligible and, as a result of low emissivity of the inside of the vacuum tanks, thermal radiation is limited. A detailed study of the thermal behaviour of these magnets is reported and compared with measurements. In addition several options to improve cooling of the ferrites are presented and analysed.

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WEPVA102

Design of the New CERN n_TOF Neutron Spallation Target: R&D and Prototyping Activities

target, neutron, interface, proton

3503

R. Esposito, M. Calviani, T. Coiffet, M. Delonca, L. Dufay-Chanat, E. Gallay, M. Guinchard, D. Horvath, T. Koettig, A.P. Perez, A.T. Perez Fontenla, A. Perillo-Marcone, S. Sgobba, M.A. Timmins, A. Vacca, V. Vlachoudis
CERN, Geneva, Switzerland
M. Beregret
UTBM, Belfort, France
L. Gomez Pereira
University of Vigo, Pontevedra, Spain
F. Latini
University of Rome La Sapienza, Rome, Italy
R. Logé
EPFL, Lausanne, Switzerland

A new spallation target for the CERN neutron time-of-flight facility will be installed during Long Shutdown 2 (2019-2020), with the objective of improving operational reliability, avoiding water contamination of spallation products, corrosion/erosion and creep phenomena, as well as optimizing it for the 20 m distant vertical experimental area 2, whilst keeping the same physics performances of the current target at the 200 m far experimental area 1. Several solutions have been studied with FLUKA Monte Carlo simulations in order to find the optimal solution with respect to neutron fluence, photon background, resolution function, energy deposition and radiation damage. Thermo-mechanical studies (including CFD simulations) have been performed in order to evaluate and optimize the target ability to withstand the beam loads in terms of maximum temperatures reached, cooling system efficiency, maximum stresses, creep and fatigue behaviour of the target materials, leading to a preliminary mechanical design of the target. This paper also covers the further prototyping and material characterization activities carried out in order to validate the feasibility of the investigated solutions.

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WEPVA103

Renovation of CERN Antiproton Production Target Area and Associated Design, Testing and R&D Activities

target, antiproton, proton, simulation

3506

C. Torregrosa, M.E.J. Butcher, M. Calviani, A. De Macedo, S. De Man, R. Ferriere, E. Grenier-Boley, B. Lefort, E. Lopez Sola, A. Perillo-Marcone, M.A. Timmins
CERN, Geneva, Switzerland

In the Antiproton Decelerator (AD) Target Area antiprotons are produced by the collisions of 26 GeV/c proton beam with a fixed target. They are then collected by a 400 kA pulsed magnetic horn, momentum selected and injected into the AD facility. The area has been in operation since the 80s, keeping most of the equipment dating back to this period. A major upgrade is foreseen during the CERN's Long Shutdown 2 to guarantee the next decades of antiproton physics. Among other R&D activities, three main systems are within the scope of this upgrade; (i) a new antiproton target design, pressurized-air-cooled and with a new core configuration based on the results from the HiRadMat27 experiment. (ii) Manufacturing of a set of new magnetic horns and testing them using a dedicated test bench replicating the real horn setup. (iii) Design of new target and horn's trolleys, which are responsible for their positioning as well as providing an efficient long term maintenance giving the high radioactivity of the area. This paper presents an overview of these and other critical activities associated to the renovation of the target area, including status and direction of the new proposed designs.

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WEPVA106

A Consolidation Roadmap for the CERN Power Converters

controls, hardware, software, experiment

3514

D. Nisbet, J.-P. Burnet
CERN, Geneva, Switzerland

At CERN the Electrical Power Converter group is re-sponsible for the design and exploitation of more than 5000 power systems throughout the accelerator complex, powering predominantly magnet circuits, in addition to RF and electro-static systems. Currently, a variety of systems are in operation, in some cases these are over 30 years old. Furthermore, the group must maintain operationally a total of six hardware platforms, each with dedicated software. In light of this, a consolidation roadmap has been determined to rejuvenate the power converter complex and to reduce the total number of control platforms. This paper presents a summary of the CERN power converter equipment to be consolidated, and the roadmap to achieve consolidation.

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WEPVA108

Operational Feedback and Analysis of Current and Future Designs of the Injection Protection Absorbers in the Large Hadron Collider at CERN

injection, vacuum, impedance, alignment

3517

D. Carbajo Perez, N. Biancacci, C. Bracco, G. Bregliozzi, M. Calviani, M.I. Frankl, L. Gentini, S.S. Gilardoni, G. Iadarola, I. Lamas Garcia, A. Lechner, A. Perillo-Marcone, B. Salvant
CERN, Geneva, Switzerland

Two injection protection absorbers, so-called TDIs (Target Dump Injection), are installed close to Interaction Points IP2 and IP8 of the Large Hadron Collider (LHC) right downstream of the injection kicker magnets (MKI). Malfunction or timing errors in the latter lead to wrong steering of the beam, which must then be intercepted by the TDI to avoid downstream equipment (which includes superconducting magnets) damage. In recent years, MKI failures during operation have brought to light opportunities for improvement of the TDI. The upgrade of this absorber, so-called TDIS (where S stands for segmented), is conceived as part of the High Luminosity-LHC (HL-LHC) project and those operational issues are taken into account for its design. The present document describes not only the aspects related to the current TDI performance and their impact in its successor's design but also the key modifications to cope with the stronger requirements associated to the higher luminosity goal.

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WEPVA109

Design of the New PS Internal Dumps, in the Framework of the LHC Injector Upgrade (LIU) Project

simulation, dumping, injection, vacuum

3521

G. Romagnoli, J.A. Briz Monago, M. Calviani, J.J. Esala, E. Grenier-Boley, A. Masi, F.-X. Nuiry, A. Perillo-Marcone, T. Polzin, V. Vlachoudis
CERN, Geneva, Switzerland

For the LHC injectors upgrade (LIU) at CERN, the two PS (Proton Synchrotron) dumps will be redesigned and upgraded for the new high intensity beams. The EN-STI group is in charge of the design and installation of the new dumps, foreseen for the next CERN's Long Shutdown in 2019-2020. As internal dumps, the PS dumps have been installed in 1975 directly in the PS vacuum ring between the main bending magnets and they are operating since then. The dumps enter the beam line when requested by beam operation, with a 6 kg Cu block moved quickly with a spring-based mechanism. This Cu block is not expected to survive the impact of the future beams. A new design is presented for the dump core based on FLUKA-ANSYS coupled simulations. The dumps should work with any PS beam foreseen within LIU, be water cooled in ultra-high vacuum medium, and enter the beam chamber in less than 250 ms. The dump should be used 200000 times per year, with a lifetime of 20 years, with almost zero maintenance. The new challenging design is based on an oscillating thin blade shaving turn after turn the circulating beam. The material considered for the blade are Cu, Ti or CuCrZr with embedded cooling channels.

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WEPVA110

Analysis and Operational Feedback on the New Design of the High Energy Beam Dump in the CERN SPS

vacuum, simulation, shielding, interlocks

3524

P. Rios Rodriguez, J.A. Briz Monago, M. Calviani, K. Cornelis, S. De Man, R. Esposito, S.S. Gilardoni, B. Goddard, J.L. Grenard, D. Grenier, M. Grieco, J. Humbert, V. Kain, F.M. Leaux, C. Pasquino, A. Perillo-Marcone, J.R.F. Poujol, S. Sgobba, D. Steyart, F.M. Velotti, V. Vlachoudis
CERN, Geneva, Switzerland

CERN's Super Proton Synchrotron (SPS) high-energy internal dump (Target Internal Dump Vertical Graphite, known as TIDVG) is required to intercept beams from 10² to 450 GeV. The equipment installed in 2014 (TIDVG#3) featured an absorbing core composed of different materials surrounded by a water-cooled copper jacket, which hold the UHV of the machine. An inspection of a previous equipment (TIDVG#2) in 2013 revealed significant beam induced damage to the aluminium section of the dump, which required imposing operational limitations to minimise the risk of reproducing this phenomenon. Additionally, in 2016 a vacuum leak was detected in the dump assembly, which imposed further limitations, i.e. a reduction of the beam intensity that could be dumped per SPS supercycle. This paper presents a new design (TIDVG#4), which focuses on improving the operational robustness of the device. Moreover, thanks to the added instrumentation, a careful analysis of its performance (both experimentally and during operation) will be possible. These studies will help validating technical solutions for the design of the future SPS dump to be installed during CERN's Long Shutdown 2 in 2020 (TIDVG#5).

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WEPVA114

Optimising Machine-Experiment Interventions in HL-LHC

shielding, radiation, experiment, vacuum

3540

F. Sanchez Galan, C. Adorisio, I. Bergstrom, D. Brethoux, S. Evrard, A. Gaddi, L.P. Krzkempek, M. Lazzaroni, J. Perez Espinos, M. Raymond, H. Vincke
CERN, Geneva, Switzerland

Funding: This Research is supported by the HL-LHC project
The luminosity reach of the HL-LHC experiments implies new constraints for the protection of the inner triplets from the machine debris. In general activation levels will increase a factor of 15-30 from the 2015 values (LS1), affecting both radiation tolerance of equipment and maintenance scenarios. The design of new equipment takes into account these constraints and the entire layout of tunnel equipment near the interaction regions will al-low for simplified maintenance. In particular, new ab-sorbers will replace the existing protection of the ma-chine-experiment cavern boundaries, with an optimised layout of the region. This paper summarises the main constraints (both physical and operational) existing at the region, together with the solutions adopted to reduce worker's dose.

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WEPVA122

Two Year Operational Experience With the Tps Vacuum System

vacuum, storage-ring, synchrotron, radiation

3557

Y.C. Yang, C.K. Chan, J. -Y. Chuang, Y.T. Huang, C.C. Liang, I.C. Sheng
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS), a 3-GeV third generation synchrotron light source, was commissioned in 2014 December and is now currently operated in top-up mode at 300mA for users. During the past two years, the machine was completed to meet design goals with among others the installation of superconducting cavities (SRF), the installation of insertion devices (ID) and the correction of vacuum chamber structure downstream from the IDs. The design goal of 500mA beam current was achieved with a total accumulated beam dose of more than 1000Ah, resulting in three orders of magnitude reduction of out-gassing. As the beam current was increased, a few vacuum problems were encountered, including vacuum leaks, unexpected pressure bursts, etc. Vacuum related issues including high pressure events, lessons learned and operational experience will be presented and discussed in this paper.

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WEPVA128

The Data Acquisition System and Inspection Equipment on Vibration Evaluation for Deionized and Cooling Water Pumps in TPS

coupling, status, data-acquisition, alignment

3568

Y.-H. Liu, Y.-C. Chung, C.K. Kuan, Z.-D. Tsai
NSRRC, Hsinchu, Taiwan

The purpose of this paper is to evaluate the vibration amplitude and spectrum for TPS water pump systems. The utility systems operate continuously since 2014, some of deionized and cooling water pumps produced higher vibration amplitude and noise during operation. The possibly reason could be poor system accuracy, inappropriate installation and commission adjustment. The data acquisition system on vibration evaluation for deionizes water pumps was established in 2016. Accord-ing to the long-tern vibration amplitude recording, the system operational status could be clarified. After vibra-tion test for several months, the bearing of booster deion-ized water pump was found abrasive since coupling be-tween motor and pump misaligned. Besides, the founda-tion of copper deionized water pump system was broken and observed by rapidly increase vibration amplitude in short term. The water pump systems were repaired and maintained base on vibration evaluation. There is still some remain problems for deionized and cooling water pump systems. The utility systems could prevent mal-function through regular vibration inspection and daily data acquisition.

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WEPVA131

Single-Inductor Bipolar Outputs Power Converters

power-supply, impedance, controls, electronics

3577

Y.T. Li, C.Y. Liu, K.-B. Liu, B.S. Wang, Y.S. Wong
NSRRC, Hsinchu, Taiwan

In the circuit design for electronic products, bipolar power supply is often required. A non-isolated dual polarity power supply design is using two inductors to achieve this function. The number of inductors on the circuit would increase both the cost of products and space requirement. So the use of a single inductor bipolar power converter design can effectively reduce the cost and space to enhance product competitiveness. In this paper, the principle of a new single-inductor bipolar power converter will be described and tested to prove the feasibility of this design.

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WEPVA140

Design Studies and Optimization of High-Field Nb₃Sn Dipole Magnets for a Future Very High Energy pp Collider

dipole, collider, magnet-design, quadrupole

3597

V.V. Kashikhin, I. Novitski, A.V. Zlobin
Fermilab, Batavia, Illinois, USA

Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
High filed accelerator magnets with operating fields of 15-16 T based on the Nb3Sn superconductor are being considered for the LHC energy upgrade or a future Very High Energy pp Collider. Magnet design studies are being conducted in the U.S., Europe and Asia to explore the limits of the Nb3Sn accelerator magnet technology while optimizing the magnet design and performance parame-ters, and reducing magnet cost. The first results of these studies performed at Fermilab in the framework of the US-MDP are reported in this paper.

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WEPVA141

Ion Cyclotron Resonance Heating Transmitter Opening Switch Upgrade

plasma, high-voltage, impedance, resonance

3600

M.P.J. Gaudreau, M.K. Kempkes, J. Kinross-Wright, R.E. Simpson
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Diversified Technologies Inc. (DTI) has installed a high-power solid-state opening switch upgrade package to replace the mercury ignitron crowbars in the Ion Cyclotron Resonance Heating (ICRH) Transmitters at MIT Plasma Fusion Science Center's (PFSC) Alcator C Mod, a Tokamak-type fusion experimental device. The speed of the series opening switch avoids the large fault currents on the transformer and power feed inherent with a crowbar. This improvement enables re-optimization of the Transformer/Rectifier (T/R) set, ultimately allowing increased power output and increased tetrode reliability. The ratings of the prior high voltage power supply are a compromise between high output power (lower impedance required from the T/R set) and crowbar reliability (higher impedance required from the power supply to limit fault current). DTI's opening switch upgrade safely allows the use of significantly reduced transformer impedance and lower droop, giving increased power as well as improved tube protection. DTI's opening switch kit can readily be adapted to any similar transmitters as an upgrade from a crowbar.

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WEPVA146

Vacuum System Design and Simulation for CHESS-U

vacuum, dipole, distributed, electron

3612

Y. Li, S.T. Barrett, D.C. Burke, J.V. Conway, X. Liu, A. Lyndaker
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work is supported by National Science Foundation Reward #DMR-1332208
A major upgrade project (dubbed CHESS-U) is planned to elevate performance of Cornell High Energy Synchrotron Source (CHESS) to the state-of-art 3rd generation light sources. In the project, about 80-m of Cornell Electron Storage Ring (CESR) will be replaced with double-bend achromat (DBA) lattice to reduce electron beam emittance. In this presentation, we will describe designs of the CHESS-U vacuum system, including new beam pipe extrusions and chambers, sliding joints, and crotch absorbers. Vacuum pumping system consists of distributed pumps (in the form of NEG strips) in the dipole chambers, and compact discrete NEG/Ion pumps in the quad straight and undulator beampipes. MolFlow+ is used to evaluate pumping performances of the CHESS-U vacuum system. First, we demonstrate that the planned vacuum pumping system can achieve and sustain required ultra-high vacuum level in CHESS-U operations, after an initial beam conditioning. Second, we will explore beam commissioning processes of the new vacuum chambers, and simulate the saturation of the NEG strips during the commissioning. These simulations will aid continuing design optimization for the CHESS-U vacuum pumping system.

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THOAA3

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

LLRF, cavity, linac, cryomodule

3638

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

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

Slides THOAA3 [15.800 MB]

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THOAB2

MicroTCA Technology Lab at DESY: Start-Up Phase Summary

electronics, hardware, site, FPGA

3659

T. Walter, M. Fenner, K. Kull, H. Schlarb
DESY, Hamburg, Germany

Funding: The MicroTCA Technology Lab at DESY is a Helmholtz Innovation Lab (HIL-02) and jointly funded by DESY, the Helmholtz Association, and industry.
Over the last decade, technology transfer has emerged as an important mission of major public research facilities. Funding agencies, regional governments and society at large have placed high hopes in the combination of scientific research and on-site technology transfer departments that can turn discoveries and research tools into marketable products. Pursuing economic interests while preserving scientific freedom is a delicate balancing act that requires novel instruments in finance, administration and governance. The Helmholtz Association of German Research Centres addressed this challenge with a set of new frameworks: the Helmholtz Validation Funds (HVF) and the Helmholtz Innovation Labs (HIL). MicroTCA is a case in point: Since 2009, DESY has upgraded this standard significantly to provide state-of-the-art LLRF systems for the facilities FLASH and European XFEL. When the technology sparked interest elsewhere, DESY bundled its transfer activities in the HVF project MicroTCA.4 for Industry (2012-2015) and the HIL project MicroTCA Technology Lab (since October 2016). We report on intermediate results achieved by the MicroTCA Technology Lab after seven months of operation.

Slides THOAB2 [6.655 MB]

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THOBB1

High Power Test Results of the Eli-NP S-Band Gun Fabricated with the New Clamping Technology Without Brazing

gun, vacuum, cathode, klystron

3662

D. Alesini, A. Battisti, M. Bellaveglia, A. Falone, A. Gallo, V.L. Lollo, L. Pellegrino, S. Pioli, S. Tomassini, A. Variola
INFN/LNF, Frascati (Roma), Italy
F. Cardelli, L. Palumbo
University of Rome La Sapienza, Rome, Italy
L. Ficcadenti, V. Pettinacci
INFN-Roma, Roma, Italy
D.T. Palmer
Istituto Nazionale di Fisica Nucleare, Milano, Italy
L. Piersanti
INFN-Roma1, Rome, Italy

High gradient RF photoguns have been a key development to enable several applications of high quality electron beams. They allow the generation of beams with very high peak current and low transverse emittance, satisfying the tight demands for free-electron lasers, energy recovery Linacs, Compton/Thomson Sources and high-energy linear colliders. A new fabrication technique for this type of structures has been recently developed and implemented at the Laboratories of the National Institute of Nuclear physics in Frascati (LNF-INFN, Italy). It is based on the use of special RF-vacuum gaskets that allow avoiding brazing in the realization process. The S-band gun of the Compton-based ELI-NP gamma beam system (GBS) has been fabricated with this new technique. It operates at 100 Hz with 120 MV/m cathode peak field and long RF pulses to allow the 32 bunch generation foreseen for the GBS. High gradient tests have been performed at full power full repetition rate and have shown the extremely good performances of the structure in term of breakdown rates. In the paper we report and discuss all experimental results with details of the electromagnetic design and mechanical realization processes.

Slides THOBB1 [6.211 MB]

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THPAB002

Update of the Collective Effects Studies for Sirius

impedance, simulation, radiation, undulator

3680

F.H. de Sá, H.O.C. Duarte, L. Liu
LNLS, Campinas, Brazil

An updated impedance budget for Sirius, with contributions from 3D electromagnetic simulations and analytic calculations, is presented and the estimates for single and multi-bunch instability thresholds for the first operation phase are re-evaluated.

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THPAB029

Simulation of the Single Bunch Instabilities for the High Energy Photon Source

impedance, injection, simulation, photon

3760

Z. Duan, N. Wang, H.S. Xu
IHEP, Beijing, People's Republic of China

Funding: Work supported by Natural Science Foundation of China (No.11605212).
Timing modes pursing a large single bunch charge will be important operation modes for the green-field High Energy Photon Source (HEPS). The single bunch instabilities are simulated with the elegant tracking code, based on the current impedance budget. In particular, a novel on-axis accumulation scheme* based on the RF gymnastics of an active double-RF system was proposed as a candidate injection scheme for HEPS, while the zero-current rms bunch length dramatically decreases during the injection, from 32 mm to 3 mm, over a time duration of about 200 ms. The single bunch instabilities are evaluated for both the operation mode with optimal bunch lengthening as well as the injection mode with the very short bunch length, as a first step in understanding the possible beam instability for this injection scheme.
* G. Xu, et al., in Proc. IPAC'16, pp. 2886-2888. Z. Duan, et al., in Proc. eeFACT 2016.

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THPAB030

Studies on Collective Instabilities in HEPS

impedance, injection, ion, damping

3763

N. Wang, Z. Duan, C. Li, S.K. Tian, H.S. Xu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS) is a new designed photon source at beam energy of 6 GeV. Due to the small beam size and increased coupling impedance with the restricted beam pipe aperture, the collective effects may bring new challenges to the physical design of the machine. The collective instabilities are estimated for different operation mode. The critical instability issues are also identified for each mode.

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THPAB038

DYNAC: Extensions, Updates, and Upgrades

simulation, lattice, linac, quadrupole

3784

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

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

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THPAB039

Novel Manufacturing Concepts for 12 GHz High Gradient Accelerating Structures

vacuum, alignment, linac, damping

3787

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

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

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THPAB040

Destabilising Effect of Linear Coupling in the LHC

coupling, simulation, damping, octupole

3791

L.R. Carver, D. Amorim, N. Biancacci, X. Buffat, K.S.B. Li, E. Métral, B. Salvant, M. Schenk
CERN, Geneva, Switzerland

During operation in 2015 and 2016, some transverse instabilities were observed when either the coupling (or closest tune approach) C- was large, or when the tunes were moved closer together. This motivated a campaign of simulations on the effect of linear coupling on the transverse stability. Measurements made during operation and with dedicated beam time have been found to confirm the predictions. This paper will detail the results of the linear coupling studies and relate them to operation of the LHC in the future.

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THPAB042

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

luminosity, simulation, emittance, 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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THPAB075

Accelerator Driven Subcritical Reactors for Profitable Disposition of Surplus Weapons-Grade Plutonium and Energy Generation

neutron, proton, target, simulation

3883

M.A. Cummings, R.J. Abrams, R.P. Johnson, T.J. Roberts
Muons, Inc, Illinois, USA

We discuss the GEM*STAR reactor concept, which addresses all historical reactor failures, which includes an internal spallation neutron target and high temperature molten salt fuel with continuous purging of volatile radioactive fission products such that the reactor contains less than a critical mass and almost a million times fewer volatile radioactive fission products than conventional reactors like those at Fukushima. GEM*STAR is a reactor that without redesign will burn spent nuclear fuel, natural uranium, thorium, or surplus weapons material. It will operate without the need for a critical core, fuel enrichment, or reprocessing making it an excellent candidate for export. While conventional nuclear reactors are becoming more and more difficult to license and expensive to build, SRF technology development is on a steep learning curve and the simplicity implied by subcritical operation will lead to reductions in regulatory hurdles and construction complexity.

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THPAB095

Detuning Compensation in SC Cavities Using Kalman Filters

cavity, controls, FPGA, coupling

3938

A. Ushakov, P. Echevarria, A. Neumann
HZB, Berlin, Germany

For CW driven superconducting cavities operating at small bandwidth, like in ERL or FEL light sources, it is mandatory to precisely control any source of detuning. Therefore, a Kalman [1] filter based approach was developed and implemented as FPGA firmware to act as the core part of a detuning compensation algorithm. It relies on a fit by a second order model to a measured transfer function of cavity's forced oscillations with damping, caused by piezo drives and data about observed current phase with some adjustable confidence rate. The initial data for this core is taken from field detection firmware on mTCA.4's SIS8300-L2 digitizer, transferred by low latency links to a carrier board equipped by piezo drive controller where the DSP processing by the Kalman algorithm performed. The processing is characterized by a 550 kHz rate in pipeline mode and occupies almost all DSP resources of the Spartan 6 FPGA chip. The experimental results of detuning compensating technique applied to a SC photoinjector cavity are presented in this contribution.
Kalman, R. E. (1960): A New Approach to Linear Filtering and Prediction Problems, Transaction of the ASME, Journal of Basic Engineering, Pages 35-45.

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THPAB096

Automatized Optimization of Beam Lines Using Evolutionary Algorithms

ion, injection, simulation, quadrupole

3941

S. Appel, V. Chetvertkova, W. Geithner, F. Herfurth, U. Krause, S. Reimann, M. Sapinski, P. Schütt
GSI, Darmstadt, Germany
D. Österle
KIT, Karlsruhe, Germany

Due to the massive parallel operation modes at GSI accelerators, a lot of accelerator setup and re-adjustment has to be made by operators during a beam time. This is typically done manually using potentiometers and is very time-consuming. With the FAIR project the complexity of the accelerator facility increases further and for efficiency reasons it is recommended to establish a high level of automation for future operation. Modern Accelerator Control Systems allow a fast access to both, accelerator settings and beam diagnostics data. This provides the opportunity to implement algorithms for automated adjustment of e.g. magnet settings to maximize transmission and optimize required beam parameters. The fast-switching magnets in GSI-beamlines are an optimal basis for an automatic exploration of the parameter-space. The optimization of the parameters for the SIS18 multi-turn-injection using a genetic algorithm has already been simulated*. The first results of our automatized online parameter optimization at the CRYRING@ESR injector are presented here.
[*] S. Appel, O. Boine-Frankenheim: Optimization of Multi-turn Injection into a Heavy-Ion Synchrotron using Genetic Algorithms, Proceedings of IPAC2015, Richmond, USA (2015)

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THPAB097

Phase Calibration of Synchrotron RF Signals

cavity, synchrotron, LLRF, timing

3945

A. Andreev, H. Klingbeil
TEMF, TU Darmstadt, Darmstadt, Germany
H. Klingbeil, D.E.M. Lens
GSI, Darmstadt, Germany

In the scope of FAIR's scientific program higher beam intensities will be achieved and several new synchrotrons (including storage rings) are being built. The low-level RF (LLRF) systems of FAIR have to support multi-harmonic operations, barrier bucket generation and bunch compression in order to meet the desired beam quality requirements. All this imposes several requirements on the LLRF systems. For example the phase error of the gap voltage of a specific RF cavity must be less than 3 degrees. Thus, each individual component must have a better accuracy. The RF reference signals for the FAIR synchrotron RF cavity systems are generated by direct digital synthesis (DDS). Four so-called Group DDS modules are mounted in one crate. In the supply rooms, the reference signals of such a crate are then distributed to local cavity LLRF systems. Therefore, the precise phase calibration of Group DDS modules is of importance. A phase calibration method with respect to the absolute phases of DDS modules defined by means of the FAIR Bunch Phase Timing System (BuTiS) is developed, and its precision is under evaluation.

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THPAB098

Test Setup for Automated Barrier Bucket Signal Generation

cavity, controls, synchrotron, antiproton

3948

K. Groß, D. Domont-Yankulova, J. Harzheim, H. Klingbeil
TEMF, TU Darmstadt, Darmstadt, Germany
M. Frey, H. Klingbeil
GSI, Darmstadt, Germany

Funding: Work supported by the German Federal Ministry of Education and Research (BMBF) under the project 05P15RDRBA.
For sophisticated beam manipulation several ring accelerators at FAIR and GSI like the main synchrotron SIS100 and the ESR will be equipped with barrier bucket systems. Hence, the associated LLRF has to be applicable to different RF systems, with respect to the cavity layout and the power amplifier used, as well as to variable repetition rates and amplitudes. Since already the first barrier bucket pulse of a long sequence has to meet certain minimum demands, an open-loop control on the basis of calibration data is foreseen. Closed-loop control is required to improve the signal quality during a sequence of pulses and to adapt to changing conditions like temperature drifts. A test setup was realized that allows controlling the signal generator, reading out the oscilloscope as well as processing the collected data. Frequency and time domain methods can be implemented to approach the dynamics of the RF system successively and under operating conditions, i.e. generating single sine pulses. The setup and first results from measurements are presented as a step towards automated acquisition of calibration data and iterative improvement of the same.

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THPAB099

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

controls, HOM, beam-loading, linac

3951

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

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

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THPAB103

On-Line RF Amplitude and Phase Calibration

cavity, controls, LLRF, beam-loading

3957

M.K. Grecki, V. Ayvazyan, J. Branlard, M. Hoffmann, M. Omet, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany

The accelerating RF field has crucial importance on the beam properties. It is not only used just to accelerate particles but also to shape the bunches at bunch compressors. It is really important to control and measure the field as seen by the beam while usually only indirect (not using the beam) field measurements are available*. Since they are affected by many contributions the measurements must be always calibrated to the beam. Usually this calibration is performed at special operating conditions that prevents normal operation of the accelerator. During normal operation the calibrations is assumed to not drift which is certainly not perfectly true and introduce some control errors. The paper shows how to extract the RF-beam calibration from RF signals during normal operating condition (when RF feed-back, beam loading compensation, learning feed-forward etc. are active). All the algorithms and computations were performed on signals recorded at FLASH accelerator but the main idea is general and can be used at other locations as well.

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THPAB104

Engineering Documentation and Asset Management for the European XFEL Accelerator

database, interface, status, SRF

3960

L. Hagge, J.A. Dammann, T.T. Hongisto, J. Kreutzkamp, D. Käfer, B. List, S. Rohwedder, S. Sühl, N. Welle
DESY, Hamburg, Germany
A. Frank
European XFEL, Schenefeld, Germany

At the European XFEL, extensive technical documentation has been created during design and construction of the accelerator. It is based on a configuration database (the DESY EDMS), which provides an inventory of major accelerator systems. The configuration database registers components and their used materials, tracks component design and fabrication history, and contains engineering documents and drawings, and work and inspection records. Technical documentation can be accessed through intuitive reports and navigational tree structures, representing specific beamline sections or areas of the facility. Access on mobile devices in the accelerator tunnel is supported by component tags with QR codes. A dedicated front-end has been developed for automatically uploading and cross-linking documents to the configuration database, reducing documentation efforts in the project teams. The configuration database now serves as a foundation for upcoming technical operation and maintenance activities. The paper provides an overview of the available engineering documentation and its access methods, and discusses its expected role and benefits in future maintenance processes.

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THPAB105

Design and Operation of the Integrated 1.3 GHz Optical Reference Module with Femtosecond Precision

laser, detector, controls, FEL

3963

T. Lamb, L. Butkowski, E.P. Felber, M. Felber, M. Fenner, S. Jabłoński, T. Kozak, J.M. Müller, P. Prędki, H. Schlarb, C. Sydlo, M. Titberidze, F. Zummack
DESY, Hamburg, Germany

In modern Free-Electron Lasers like FLASH or the European XFEL, the short and long-term stability of RF reference signals gains in importance. The requirements are driven by the demand for short FEL pulses and low-jitter FEL operation. In previous publications, a novel, integrated Mach-Zehnder Interferometer based scheme for a phase detector between the optical and the electrical domain was presented and evaluated. This Laser-to-RF phase detector is the key component of the integrated 1.3 GHz Optical Reference Module (REFM-OPT) for FLASH and the European XFEL. The REFM-OPT will phase-stabilize 1.3 GHz RF reference signals to the pulsed optical synchronization systems in these accelerators. Design choices in the final hardware configuration are presented together with measurement results and a performance evaluation from the first operation period in the European XFEL.

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THPAB106

Experience with Single Cavity and Piezo Controls for Short, Long Pulse and CW Operation

cavity, feedback, controls, experiment

3966

K.P. Przygoda, V. Ayvazyan, R. Rybaniec, H. Schlarb, Ch. Schmidt, J.K. Sekutowicz
DESY, Hamburg, Germany
P. Echevarria
HZB, Berlin, Germany

We present a compact RF control system for SCRF single cavities based on MicroTCA.4 equipped with specialized advanced mezzanine cards (AMCs) and rear transition modules (RTMs). To sense the RF signals from the cavity and to drive the high power source, a DRTM-DWC8VM1 module is used equipped with 8 analog field detectors and one RF vector modulator. Fast cavity frequency tuning is achieved by piezo-actuators attached to the cavity and a RTM piezo-driver module (DRTM-PZT4). Data processing of the RF signals and the real-time control algorithms are implemented on a Virtex-6 FPGA and a Spartan FPGAs within two AMCs (SIS8300-L2V2 and DAMC-FMC20). The compact single cavity control system was tested at Cryo Module Test Bench (CMTB) at DESY. Software and firmware were developed to support all possible modes, the short pulse (SP), the long pulse (LP) and CW operation mode with duty cycles ranging from 1 % to 100%. The SP mode used a high power multi-beam klystron at low QL ~3·10⁶. For the LP mode (up to 50% duty cycle) and the CW mode a 120 kW IOT tube was used at QL up to 1.5·10⁷. Within this paper we present the achieved performance and report on the operation experience on such system.

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THPAB113

Time Synchronization for Distant IOCs of the SuperKEKB Accelerators

timing, EPICS, linac, network

3982

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

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

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THPAB114

Operation of LLRF Control Systems in SuperKEKB Phase-1 Commissioning

controls, LLRF, cavity, simulation

3986

T. Kobayashi, K. Akai, K. Ebihara, A. Kabe, K. Nakanishi, M. Nishiwaki, J.-I. Odagiri, S.I. Yoshimoto
KEK, Ibaraki, Japan
K. Hirosawa
Sokendai, Ibaraki, Japan

First beam commissioning of SuperKEKB (Phase-1), which had started in February 2016 and continued until the end of June, has been successfully accomplished. Target beam current for Phase-1 needed for sufficient vacuum scrubbing was achieved in both 7-GeV electron and 4-GeV positron rings. This presentation summarize the operation results related to low level RF (LLRF) control issues during the Phase-1 commissioning, including the system tuning, the coupled bunch instability and the bunch gap transient effect. RF system of SuperKEKB consists of about thirty klystron stations in both rings. Newly developed LLRF control system, which is composed of recent digital technique, is applied to the nine stations among the thirty for Phase-1. The RF reference signal distribution system has been also upgraded for SuperKEKB. These new systems worked well without serious problem and they contributed to smooth progress of the commissioning. The old existing systems, which had been used in the KEKB operation, were still reused for the most stations, and they also worked as soundly as performed in the KEKB operation.

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THPAB115

Development of a Longitudinal Feedback System for Coupled Bunch Instabilities Caused by the Accelerating Mode at Superkekb

cavity, impedance, damping, target

3989

K. Hirosawa, K. Akai, E. Ezura, T. Kobayashi, K. Nakanishi, M. Nishiwaki, S.I. Yoshimoto
KEK, Ibaraki, Japan

SuperKEKB is an asymmetric energy electron-positron circular collider. Phase-I commissioning was operated from February to June in 2016. The purpose of this accelerator is to aim at the higher luminosity than KEKB, so a larger beam current is made for it. In the future plan, beam currents in the electron and positron rings will be increased to 2.6A and 3.6A, respectively. As we consider beam dynamics in the storage ring, higher mode instability associated with the accelerating mode will be caused by a large beam current. Especially the target instability of this study is called μ=-2 mode Coupled Bunch Instability. To suppress it, we developed new feedback components for longitudinal coupled bunch instability. We have same mechanism feedback components for KEKB, but it supports only μ=-1 mode instability. Since a large current makes μ=-1 mode instability big, there is a possibility that suppression is difficult only by using KEKB components. In order to deal with this problem, new components we developed support μ=-1, -2, and -3 mode instabilities, and we improved the performance and usability as compared to existing components. We schedule studies using a beam at Phase-II.

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THPAB118

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

timing, linac, network, software

4000

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

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

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THPAB121

The Study of Accelerator Data Archiving and Retrieving Software

database, EPICS, interface, software

4007

Y.S. Qiao, G. Lei, Z. Zhao
IHEP, Beijing, People's Republic of China

This paper presents a novel archiving and retrieving software designed for BEPC-II and other particle accelerators. At BEPC-II, real-time data are stored as index files recorded by traditional EPICS Channel Archiver. Never-theless, index files are not suitable for long-term maintenance and difficult for data analysis. The NoSQL database MongoDB is used for this new system due to aging technologies, so as to promote the data storage reliability, usability, and possible future advanced data analysis. A cross-platform UI (User Interface) has also been developed to make it quicker and easier to access the database. The writing and query performance are tested for this software.

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THPAB141

Control and Operation of a Wideband RF System in CERN's PS Booster

HLRF, LLRF, controls, booster

4050

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

A prototype wideband High-Level RF (HLRF) sys-tem based on Finemet metal alloy has been installed in CERN's PS Booster (PSB) Ring 4 in 2012, within the frame of the LHC Injectors Upgrade (LIU) project. A digital Low-Level RF (LLRF) system was used to control the HLRF system to ascertain the capabilities of the combined system, especially under heavy beam loading. The testing campaign was satisfactory and in 2015 the CERN management decided to replace all ferrite-based systems with Finemet ones for the PS Booster restart in 2020. This paper describes the LLRF features implemented for operating the wideband HLRF system and the main beam results obtained. Hints on the LLRF evolution in view of the PSB HLRF renovation are also given.

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THPAB142

Initial Beam Results of CERN ELENA's Digital Low-Level RF System

LLRF, HLRF, diagnostics, extraction

4054

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

The Extra Low ENergy Antiproton (ELENA) decelerator is under commissioning at CERN. This decelerator is equipped with a new digital low-level RF (LLRF) system, in-house developed and belonging to the LLRF family already deployed in CERN's PS Booster and Low Energy Ion Ring (LEIR) synchrotrons. New features to adapt it to the demanding requirements of ELENA's operation include new, low noise ADC daughtercards and a fixed-frequency clocking scheme. This paper gives an overview of the LLRF system; initial beam results are also shown together with hints on the future system upgrade.

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THPAB144

The New LEIR Digital Low-Level RF System

LLRF, HLRF, extraction, low-level-rf

4062

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

CERN's Low Energy Ion Ring (LEIR) low-level RF (LLRF) system has been successfully upgraded in 2016 to the new digital, LLRF family for frequency-sweeping synchrotrons developed at CERN. For LEIR it implements not only beam loops but also the voltage and phase loops required for the control of two Finemet-based High-Level RF (HLRF) systems. This paper gives an overview of the system and of new requirements implemented, such as the parallel operation of two HLRF systems. Beam results for the 2016 lead ions run are also shown.

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THPAB145

CERN Accelerators Topology Configuration: Facing the Next Long Shutdown

hardware, status, database, alignment

4066

S. Bartolome-Jimenez, T.W. Birtwistle, S. Chemli, N. Gilbert, A.-L. Perrot, J. Piar, V. Simetka, B. Vazquez de Prada Planas
CERN, Geneva, Switzerland

The Configuration and Layout (CL) team at CERN ensures that there is a clear and coherent representation of the status of the CERN underground facilities (about 60 km of equipment) and main accelerator projects at a given point in time. In view of the major equipment changes to be carried out during the extended end of year technical stop (EYETS), the next Long Shutdown (LS2), and to facilitate the associated preparatory work of multiple CERN groups, the CL team has developed an immersive visualisation tool, displaying 360 degree panoramic images of CERN underground facilities. In addition, the CL team is launching a process to manage future layout configurations inside the CERN Layout database in parallel to the current configuration. This paper presents the 360 degree panorama visualisation tool and the parallel configuration process, to view the past, current and future status of the CERN accelerator complex. It highlights their added value for the CERN groups in the preparatory phase for upgrade and consolidation modifications and discusses the potential future improvements.

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THPAB146

Investigation of the Remanent Field of the SPS Main Dipoles and Possible Solutions for Machine Operation

dipole, closed-orbit, extraction, proton

4069

F.M. Velotti, H. Bartosik, J. Bauche, M.C.L. Buzio, K. Cornelis, M.A. Fraser, V. Kain
CERN, Geneva, Switzerland

The CERN Super Proton Synchrotron (SPS) provides different types of beams at different extraction energies. The main magnets of the SPS are regulated with a current loop, but it has turned out that hysteresis effects from the main dipoles have a significant impact on reproducibility and hence efficiency and availability. Beam and machine parameters were found to depend on the programmed sequence of magnetic cycles - the so-called super cycle - representing the production of the different beams. The scientific program of the SPS requires frequent changes of the supercycle composition and the effect of the main magnet hysteresis has to be understood, modelled and used in accelerator control system. This paper summarises the first main field measurements carried out with the currently available systems during operational conditions as well as measurements of vital machine and beam parameters as a function of the super cycle composition. Finally, ideas will be presented to provide reproducibility by automatically correcting different parameters taking the magnetic history of the main magnets into account.

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THPAB150

Input Output Controller of Digital Low Level RF System in NSRRC

EPICS, LLRF, FPGA, controls

4083

Z.K. Liu, F.Y. Chang, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, C.H. Lo, C.L. Tsai, Ch. Wang, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan

Low Level Radio Frequency (LLRF) systems operating at NSRRC are based on analog technology and are used both at the Taiwan Light Source and the Taiwan Photon Source. In order to have better RF field stability, a new digital LLRF system based on Field Programmable Gate Array (FPGA) was developed. A card-sized single-board computer is used as the input/output controller of the digital LLRF system and its design and implementation with EPICS applications are reported here.

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THPIK012

The Magnets of BERLinPro: Specification, Design, Measurement and Quality Analysis

dipole, multipole, quadrupole, sextupole

4124

A.N. Matveenko, M. Abo-Bakr, K.B. Bürkmann-Gehrlein
HZB, Berlin, Germany
I.V. Davidyuk, O.A. Shevchenko, A.V. Utkin, N.A. Vinokurov
BINP SB RAS, Novosibirsk, Russia

Funding: Work supported by grants of Helmholtz Association VH-NG-636 and HRJRG-214
A total of 77 magnets form the magnetic lattice of the BERLinPro energy recovery linac prototype: 1+8+8 dipole magnets of three different types, 12+40 quadrupole magnets of two different types and 8 sextupole magnets have been produced by BINP. After the design phase, magnets production started in 2015, measurements and delivery took place in 2016, first assembly stage was finished in 03/2017. The motivation for the magnet specification and a summary of the basic design is given in this paper. Select-ed measurement data from the final acceptance tests are presented and analysed to ensure the magnet quality.

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THPIK029

THE RF CAVITY FOR THE INDUS-2 STORAGE RING

cavity, HOM, vacuum, dipole

4154

C. P. Pasotti, M. Bocciai, P. Pittana, M. Rinaldi
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

A new Elettra-type cavity has been delivered to the Raja Ramanna Centre for Advanced Technology (RRCAT) Indus-2 facility. This cavity is the very same of those already installed several years ago with some optimization of the cooling channels. It is the Elettra-type cavity, normal conducting copper single cell but resonating at 505.8 MHz. The cavity description, the full characterization of the accelerating mode (L0) and high order modes (HOM) and the acceptance tests are presented in this paper.

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THPIK035

Rf Properties of a 175 MHz High-Q Load Circuit

rfq, coupling, linac, vacuum

4169

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

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

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THPIK039

Multipactor Problem of J-PARC SDTL

multipactoring, cavity, simulation, linac

4184

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

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

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THPIK041

The RF System of the SESAME Storage Ring

cavity, storage-ring, controls, LLRF

4187

D.S. Foudeh, E. Huttel, N.Kh. Sawai
SESAME, Allan, Jordan

SESAME the Synchrotron Radiation Light Source in Allan (Jordan) consists of a 22 MeV Microtron, an 800 MeV Booster Synchrotron (originally from BESSY I, Berlin, Germany) and a 2.5 GeV Storage Ring (new de-sign). The RF system consists of four 500 MHz ELET-TRA cavities powered by four 80 kW Solid State Ampli-fiers whereas the first amplifier is produced by SOLEIL and the other three are produced by SIGMA-PHI. The RF plant is controlled by the digital Low Level Electronics from DIMTEL. The system has been installed end of 2016. This report describes the setup of the facility and the results of the commissioning.

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THPIK050

Measurement and Tuning of the RF Field for the CSNS DTL

DTL, cavity, coupling, experiment

4210

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

The CSNS DTL accelerates negative hydrogen ions from 3MeV to 80MeV with resonant frequency of 324MHz and peak current of 15mA. The CSNS includes four DTL cavities with diameter of 56.6cm and each length of 9 meters. RF properties research and measurement have been done to make sure the design and manufacture validate for beam operation. A new automatic system has been developed for measuring field distribution. The secondary derivation method is used to calculate the amount of the tuners to tune axial field flatness. The tilt of TS curve is used to judge the gap between the post couplers and drift tubes to achieve stability. At last the tanks have good flatness and strong stabilization, the field deviation is 2% with the standard deviation of 0.96%, and the maximum TS parameter is 65%/MHz. After the low power RF tuning experiment, the four tans have been installed in the tunnel, and have gotten good results of high power test and beam acceleration experiment.

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THPIK064

Beam Lifetime Analysis of HLS-II Storage Ring

storage-ring, scattering, vacuum, emittance

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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THPIK068

High Power Test of SINAP X-Band Deflector at KEK

cavity, electron, impedance, laser

4251

J.H. Tan, W. Fang, Q. Gu, X.X. Huang, Z.B. Li, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
T. Higo
KEK, Ibaraki, Japan
D.C. Tong
TUB, Beijing, People's Republic of China

A crucial RF structure used for bunch length measurement for Shanghai X-ray Free Electron Lasers (SXFEL) at the Shanghai Institute of Applied Physics (SINAP), Chinese Academy of Science [1]. The design, fabrication, measurement and tuning have been completed at SINAP [2], and the high power test was carried out at Nextef of KEK with international collaboration. This paper presents the RF conditioning process and test results.

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THPIK070

Localization of RF Breakdown Point in a Coaxially Loaded LINAC Cavity

linac, cavity, electron, accelerating-gradient

4254

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

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

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THPIK072

Development of High Power RF Amplifier System for the KBSI RFQ

rfq, cavity, LLRF, rf-amplifier

4257

J. Bahng
Kyungpook National University, Daegu, Republic of Korea
M.-H. Chun
PAL, Pohang, Kyungbuk, Republic of Korea
J.G. Hong, B.S. Lee, J.W. Ok
Korea Basic Science Institute, Busan, Republic of Korea
D.S. Kim
DAWONSYS, Ansan-si, Republic of Korea
E.-S. Kim
Korea University Sejong Campus, Sejong, Republic of Korea

KBSI (Korean Basic Science Institute) has been developed a compact accelerator system for generation of fast neutron by 2.7 MeV/u of lithium beam. The facility consists of 28 GHz SC-ECR ion source, LEBT, RFQ and DTL. The developed RFQ accelerator provides lithium ion beam from 12 keV/u to 500 keV/u with 98.88 % of high transmission rate at 165 MHz of operation frequency. RF power system for RFQ accelerator has been developed to provide sufficient RF power into RFQ cavity. which consists of LLRF system for control, 5 KW of SSPA as IPA, tetrode tube amplifier as FPA, coaxial transmission line and circulator for protection from reflection power provides 100 kW at operation frequency with CW mode, In this paper, we discuss about development of RF system and performance test in detail.

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THPIK073

Development of RFQ for BNCT Accelerator

rfq, cavity, proton, emittance

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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THPIK082

Quadrupole Magnet Design for the ESS MEBT

quadrupole, dipole, magnet-design, linac

4276

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

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

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THPIK084

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

klystron, factory, linac, electron

4282

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

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

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THPIK088

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

impedance, insertion, network, linac

4292

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

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

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THPIK090

352 MHz Tetrode RF Stations for Superconducting Spoke Cavities

site, linac, controls, power-supply

4296

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

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

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THPIK094

Linac4 PIMS Construction and First Operation

cavity, linac, vacuum, alignment

4307

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

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

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THPIK096

Jitter Measurement to 10ppm Level for Pulsed RF Power Amplifiers 3 - 12GHz

timing, hardware, kicker, pulsed-power

4314

C.H. Gough, S. Dordevic, M. Paraliev
PSI, Villigen PSI, Switzerland

Linacs for FEL applications require a low jitter RF path from RF source through pulsed amplifiers, klystron / modulators and cavities. For the SwissFEL project, pulsed solid state power amplifiers of the 500W / 3us class for driving the klystrons were required. For these amplifiers, a stable and reliable interferometer system was developed to measure the residual RF jitter levels to <10 ppm (parts per million) and <10 urad (0.6mdeg) rms. This paper describes the system and gives some measurement results for 3GHz, 5.7GHz and 12GHz amplifiers.

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THPIK098

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

toolkit, linac, focusing, electron

4321

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

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

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THPIK101

Quarter Wavelength Combiner for an 8.5kW Solid-State Amplifier and Conceptual Study of Hybrid Combiners

insertion, distributed, synchrotron, status

4324

T.-C. Yu, F.Y. Chang, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Z.K. Liu, C.H. Lo, C.L. Tsai, Ch. Wang, M.-S. Yeh
NSRRC, Hsinchu, Taiwan

Experimental results to combine ten 900 W solid-state amplifier modules based on typical quarter wavelength 10-way combiners are described for a total of 8.5 kW RF power output at 500 MHz. The power gain and phase distribution among the ten modules are measured and calculated to sense the combination efficiency. The combination efficiency of 100 modules differing in power gain and phase distribution is theoretically analysed. Groups of 5, 10, 25, 50 and 100 units are used in 4, 3, 2, and 1-stage power combination for total 100 units and the characteristics are calculated and investigated, including bandwidth, efficiency and even redundancy under various output VSWR levels. To simplify combining complexity and to eliminate the drawbacks of single stage combiners, a multi-way 2-stage coaxial to waveguide combiner is thus proposed as an expandable power combiner.

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THPIK103

Six Months of Operation of the New RF Cavity System of SLRI

cavity, storage-ring, radiation, status

4331

N. Juntong, Ch. Dhammatong, P. Sudmuang, N. Suradet
SLRI, Nakhon Ratchasima, Thailand

The new RF cavity system has been installed in the storage ring of SIAM Photon Source (SPS) since August 2016. The RF cavity was designed base on the MAX-IV laboratory capacitive loaded type cavity. The solid-state technology was implemented in the RF high power transmitter. The low-level RF system utilized the digital technology. The system has been successfully commissioned and run with a capability to compensate an energy lost from a full capacity run of insertion devices since August 2016. This paper summarizes the problems and actions of the new RF system and presents an overview of six months of operation of the new RF system in the storage ring of SPS.

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THPIK112

Progress With the Diamond Light Source RF Upgrade

cavity, storage-ring, superconducting-cavity, HOM

4358

C. Christou, A.G. Day, M.J. Duignan, P. Gu, N.P. Hammond, P.J. Marten, S.A. Pande, D. Spink
DLS, Oxfordshire, United Kingdom

Failure of a superconducting cavity in the Diamond storage ring can lead to extended down-time because of the time required to remove the module from the ring, the inability to access the cavity without removal from the cryostat and the long time to repair of the module. To reduce the risk to storage ring operation, normal conducting cavities are being installed to support operation of the superconducting cavities. Two cavities will be introduced in 2017 and work is progressing with RF amplifiers, transmission lines and low-level RF as well as storage ring engineering and controls. A summary of progress so far is presented and the plan for installation and further RF upgrades is outlined.

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THPIK117

High Efficiency High Power Resonant Cavity Amplifier for Accelerator Applications

cavity, coupling, impedance, network

4374

M.P.J. Gaudreau, D.B. Cope, E.G. Johnson, M.K. Kempkes, J. Kinross-Wright, R.E. Simpson
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Funding: Work supported by US Department of Energy under contract DE-SC0015780
Diversified Technologies, Inc. (DTI) has designed and built a unique integrated resonant-cavity combined solid-state amplifier. The design radically simplifies solid-state transmitters to create favorable and straightforward scaling to high power levels. A crucial innovation is demonstration of an inherently reliable soft-failure mode of operation; a failure in one or several of these myriad combined transistors has negligible performance impact. In addition, this design couples the transistor drains directly to the cavity without first transforming to 50 Ohms, avoiding the otherwise-necessary multitude of circulators, cables, and connectors. A conventional amplifier has a complete set of electrical and cooling connections for every stage, resulting in many hundreds of connections for a high power transmitter'in some DTI designs, there are as few as four. This construction both reduces the cost and increases the power level at which it is cost-effective to employ a solid-state transmitter. The prototype has demonstrated multiple-transistor combining from 300 MHz to 1300 MHz, at powers up to 5 kW. This prototype is scalable to several hundred kW at these frequencies.

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THPIK120

The RF and Mechanical Design of a Compact, 2.5 kW, 1.3 GHz Resonant Loop Coupler for the APEX Buncher Cavity

cavity, vacuum, electron, resonance

4380

S.P. Virostek, F. Sannibale, J.W. Staples
LBNL, Berkeley, California, USA
H.J. Qian
DESY Zeuthen, Zeuthen, Germany

Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
The Advanced Photo-injector Experiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL) is an injector system designed to demonstrate the capability of a normal conducting 186 MHz RF gun operating in CW mode to deliver the brightness required by X-ray FEL applications operating at MHz repetition rate, such as LCLS-II. A 240 kV, 1.3 GHz CW buncher cavity design was developed as part of the APEX experiment. The two-cell cavity profile has been optimized to minimize the RF power requirements and to remove multipacting resonances over the full range of operation. In order to excite the cavity stably at pi-mode and remove the dipole-like coupler kick, the two cells are to be independently driven by four, 2.5 kW, coaxial resonant loop couplers with integrated ceramic windows and a matching section in the body of the coupler. The coupler's inner conductor has a single diameter change at a specified distance from the ceramic insulator in order to cancel the wave reflected from the ceramic window, thus comprising the matching section. The details of the RF analysis, mechanical design, fabrication and testing of the coupler are presented here.

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THPIK122

Methods of Phase and Power Control in Magnetron Transmitters for Superconducting Accelerators

controls, injection, power-supply, SRF

4386

G.M. Kazakevich, R.P. Johnson, M.L. Neubauer
Muons, Inc, Illinois, USA
V.A. Lebedev, W. Schappert, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Various methods of phase and power control in magnetron RF sources of superconducting accelerators intended for ADS-class projects were recently developed and studied with conventional 2.45 GHz, 1 kW, CW magnetrons operating in pulsed and CW regimes. Magnetron trans-mitters excited by a resonant (injection-locking) phase-modulated signal can provide phase and power control with the rates required for precise stabilization of phase and amplitude of the accelerating field in Superconducting RF (SRF) cavities of the intensity-frontier accelerators. An innovative technique that can significantly increase the magnetron transmitter efficiency at the wide-range power control required for superconducting accelerators was developed and verified with the 2.45 GHz magnetrons operating in CW and pulsed regimes. High efficiency magnetron transmitters of this type can significantly reduce the capital and operation costs of the ADS-class accelerator projects.

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THPIK129

Non-Linear Inserts for the IOTA Ring

vacuum, electron, alignment, quadrupole

4407

F.H. O'Shea, R.B. Agustsson, P.S. Chang, Y.C. Chen
RadiaBeam, Santa Monica, California, USA
D.W. Martin, J.D. McNevin
RadiaBeam Systems, Santa Monica, California, USA

Funding: Work supported by DOE under contract DE-SC0009531.
We present here the complete non-linear insert for the IOTA ring at Fermilab. In particular, we will show the results for the magnetic measurements and a discussion of leak correction in the unusually shaped vacuum chamber. A test assembly of the insert has been successfully completed and the insert functions mechanically as designed.

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THPVA012

Transverse Impedance Measurement in SuperKEKB

damping, impedance, betatron, storage-ring

4442

N. Kuroo
UTTAC, Tsukuba, Ibaraki, Japan
T. Ishibashi, T. Mimashi, K. Ohmi, Y. Ohnishi, K. Shibata, Y. Suetsugu, S. Terui, M. Tobiyama, D. Zhou
KEK, Ibaraki, Japan

In KEK(Japan), SuperKEKB project is progressing toward upgrade. This project aims improvement luminosity (8×10³⁵ cm^-2s- 1) which is 40 times of the performance of the KEKB accelerator. In Phase 1 of this project, a performance test as storage ring was carried out. Understanding of ring Impedance/wake is an important subject in phase I. Measurement of Head Tail Damping using Turn by Turn monitor was performed to evaluate impedance/wake. Betatron motion is excited by kicker and its damping is measured for several parameters sets of bunch current and chromaticity in both HER and LER. The wake field was calculated from the decrement of betatron amplitude. We present the wake field which is cross-checked with tune shift based on the current dependence.

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THPVA029

Study of Single Bunch Instabilities with Transverse Feedback at Diamond

feedback, storage-ring, coupling, controls

4489

E. Koukovini-Platia, R. Bartolini, A.F.D. Morgan, G. Rehm
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

Single bunch instability studies have been carried out at Diamond with and without the transverse multi-bunch feedback (TMBF) system. Single bunch instability thresholds were measured for zero, positive and negative chromaticity values by increasing the current till the instability onset. The bunch-by-bunch feedback system was then used to suppress the motion of the bunch centroid and the new thresholds were measured in all chromaticity regimes. The feedback loop phase of the TMBF was changed from resistive to reactive as well as intermediate to find the optimal feedback settings that maximize the single bunch instability thresholds.

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THPVA031

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

electron, proton, extraction, emittance

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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THPVA033

Towards commissioning the Fermilab Muon g-2 Experiment

proton, experiment, target, storage-ring

4505

D. Stratakis, J.P. Morgan, M.J. Syphers
Fermilab, Batavia, Illinois, USA
A. Fiedler, M.J. Syphers
Northern Illinois University, DeKalb, Illinois, USA
S-C. Kim
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
M. Korostelev
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M. Korostelev
Lancaster University, Lancaster, United Kingdom

Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
Starting this summer, Fermilab will host a key exper-iment dedicated to the search for signals of new phys-ics: The Fermilab Muon g-2 Experiment. Its aim is to precisely measure the anomalous magnetic moment of the muon. In full operation, in order to avoid contami-nation, the newly born secondary beam is injected into a 505 m long Delivery Ring (DR) wherein it makes several revolutions before being send to the experi-ment. Part of the commissioning scenario will execute a running mode wherein the passage from the DR will be skipped. With the aid of numerical simulations, we provide estimates of the expected performance.

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THPVA039

Nanopositioning and Actuation in Extreme Environment Using Piezoelectric Multilayer Actuators and Motors

vacuum, radiation, diagnostics, electron

4519

C. Mangeot
Noliac A/S, Kvistgaard, Denmark

Piezoelectric devices find numerous applications in Science projects, when precise and fast positioning is needed, particularly in harsh environment. This paper reviews some of the latest environmental tests performed on piezoelectric devices, illustrating how they enable higher performance or even new technical solutions. In the field of particle accelerators and instrumentation, two applications can be mentioned: the precise goniometer to be installed in the Large Hadron Collider (LHC) and active Lorentz force detuning compensation systems*. Multilayer actuators have been demonstrated over a wide range of temperatures, from cryogenic (4K) to 220°C, in UHV and under radiation. Other examples can be mentioned within the ITER project: the In-Vessel Viewing System (IVVS) and the Electron Cyclotron Emission (ECE) diagnostic**. For these applications, a piezo motor is needed. The Piezo Actuator Drive (PAD) was demonstrated at high temperature, UHV and submitted to high magnetic fields.
* P. Bosland et al.; 'Mechanical study of the Saclay Piezo Tuner PTS (Piezo Tunning System)', CARE-Note-2005-004-SRF
** G. Taylor et al.; 'Status of the design of the ITER ECE diagnostic', EC18, 2015

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THPVA049

Introduction About Key Techniques of Critical Equipment in CSNS

vacuum, dipole, target, alignment

4548

L. Kang, H.Y. He, L. Liu, X.J. Nie, A.X. Wang, G.Y. Wang, J.B. Yu, J.S. Zhang, D.H. Zhu
IHEP, Beijing, People's Republic of China
J.X. Chen, C.J. Ning, Y.J. Yu
CSNS, Guangdong Province, People's Republic of China

Funding: National Natural Science Foundation of China (Grant Nos.11375217)
The China Spallation Neutron Source (CSNS) is the complex consists of a negative hydrogen linear accelerator, a rapid cycling proton synchrotron (RCS) accelerating the beam to 1.6 GeV energy, a solid target station, and instruments for spallation neutron applications. Some equipment which work in high radiation zone, such as beam dumps, collimators, proton beam window and so on, should contain the performance of long lifetime, high vacuum, and remote maintenance easily. This paper mainly introduce some key techniques in these equipment, firstly quick-release remote clamp and remote maintenance tool in collimators and proton beam window will be introduced, then some key brazing techniques in processing of these equipment will also be mentioned. Vibration online monitoring system and other key techniques will be showed finally.

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THPVA064

Timing System at ESS

timing, EPICS, distributed, proton

4588

J. Cereijo García, T. Korhonen, J.H. Lee, D.P. Piso
ESS, Lund, Sweden
R.R. Osorio
UDC, A Coruña, Spain

The European Spallation Source (ESS) is a research facility being built in Lund (Sweden) that will produce neutrons by the spallation process. It uses the Micro-Research Finland (MRF) Timing System, which provides a complete event-based timing distribution system. The timing signal generation consists of a basic topology: an Event Generator (EVG), an optical distribution layer (fan-out modules) and an array of Event Receivers (EVRs). The timing system will provide clock synchronization and timing services to devices with real time requirements. Its main purposes are event generation and distribution, time stamping and synchronous data transmission. The event clock frequency will be 88.0525 MHz, divided down from the bunch frequency of 352.21 MHz. An integer number of ticks of this clock will define the beam macropulse full length, around 2.86 ms, with a repetition rate of 14 Hz. ESS will be the first facility to deploy large amounts of uTCA EVRs, and is planning to take advantage of the features provided by the uTCA standard, like trigger and clock distribution over the backplane. These EVRs are already being deployed in some systems and test stands.

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THPVA070

Cooling and Thermo Stabilization System of 100MeV/100kW Electron Linear Accelerator of Neutron Source Driver

electron, neutron, controls, klystron

4607

M. Moisieienko, I.M. Karnaukhov, A. Mytsykov, A.Y. Zelinsky
NSC/KIPT, Kharkov, Ukraine

Cooling system and temperature control technology elements of the linear electron accelerator of 100 MeV/100kW is a complex technological system composed of three subsystems: the cooling klystron gallery equipment (30 C ± 1), cooling of the accelerator tunnel equipment (30 C ± 1) and the cooling and temperature control accelerating sections and waveguide (40 ° C ± 0,2). The block diagram of cooling and temperature control of the linear electron accelerator of 100 MeV/100 kW, describes the basic principles to formulate requirements to the cooling systems. It describes the status of the installation, commissioning and testing of the cooling and temperature control of the accelerator - driver subcritical neutron source KIPT.

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THPVA083

First Tests of a Re-accelerated Beam at Heidelberg Ion-Beam Therapy Centre (HIT)

synchrotron, extraction, ion, acceleration

4647

C. Schömers, E. Feldmeier, M. Galonska, Th. Haberer, J.T. Horn, A. Peters
HIT, Heidelberg, Germany

In the active raster scanning method performed at HIT since 2009, tumors are irradiated slice-by-slice by changing the extraction energy. The synchrotron provides a library of 255 different extraction-energy levels per ion type, according to the aimed penetration depth. So far, a new synchrotron cycle is started for each iso-energy-slice resulting in a non-optimal duty cycle. In order to reduce treatment time and to increase the number of patients treated per day, synchrotron cycles with several extraction flattops on different energy levels are planned. After completing one iso-energy-slice, remaining particles will be reaccelerated to the adjacent level. As a first test a new data supply model generating patterns for power supplies and RF devices with two different extraction flattops has been implemented recently. The properties of the reaccelerated beam are now under detailed examination. The reaccelerated beam was successfully extracted and guided to the experimental area. Ionization chambers along the beam line clearly show two spills on two different extraction flattops. The desired change of beam energy has been verified by range measurements in a water column.

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THPVA087

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

cavity, simulation, electron, linac

4660

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

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

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THPVA095

Storage Ring Injection Kickers Alignment Optimization in NSLS-II

kicker, injection, timing, storage-ring

4683

G.M. Wang, W.X. Cheng, J. Choi, T.V. Shaftan, X. Yang
BNL, Upton, Long Island, New York, USA

The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source at Brookhaven National Laboratory. The SR is designed to work in top-off injection mode. The injection straight includes a septum and four fast kicker magnets with independent amplitude and timing control. Ideally, fast kickers formed a local bump, which is transparent to stored beam during top off injection. Due to mismatch of kicker voltage, timing or waveform, there is residual betatron oscillation and impact normal operation. This paper will present the injection kicker waveform measurement with beam, local and global alignment optimization to in improve top off injection transition.

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THPVA097

Estimation and Measurements of Radiation Dose Distibution for the Radiation Test Area in J-PARC Main Ring

radiation, neutron, proton, photon

4689

M.J. Shirakata
KEK, Ibaraki, Japan

The J-PARC main ring has a beam collimator system in the first straight section for the beam halo rejection. Though it makes a high radiation area in the ring which requires a serious maintenance scheme, a high radiation dose can be applied to the tests of radiation resistible devices. The radiation dose distribution was estimated by using PHITS code, and it was confirmed by dose meas-urements using RadMon, nanoDot OSL dosimeters with continuous monitoring of beam losses. The availability of the radiation test area in the accelerator ring is reported in this paper.

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THPVA101

Scanning Irradiation System at SAGA-HIMAT

synchrotron, extraction, ion, lattice

4698

M. Kanazawa, M. Endo, T. Himukai, M. Kitamura, M. Mizota, A. Nakagawara, H. Sato, Y. Shioyama, T. Totoki, Y. Tsunashima
SAGA HIMAT, Saga, Japan

In SAGA-HIMAT, 620 patients have been treated by use of two irradiation rooms in 2015 financial year, where passive irradiation method is adopted. To increase treatment capacity of our facility, we have started the construction of the third treatment room at the beginning of 2014 with a scanning irradiation system. In the new treatment room (room C), there are horizontal and vertical irradiation courses. This construction was required to carry out without interruptions on the treatments in room A and room B. At the end of 2016 financial year, the system tests are almost scheduled to be ready for treatment. In this presentation, we will give obtained performances of our scanning system.

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THPVA125

Status of Commissioning of Gantry 3 at the PSI PROSCAN Facility

coupling, interface, controls, proton

4744

A. Koschik, J.P. Duppich, M. Eichin, P. Fernandez Carmona, A. Gerbershagen, A.L. Lomax, D. Meer, S. Safai, J.M. Schippers, D.C. Weber
PSI, Villigen PSI, Switzerland

Paul Scherrer Institute currently extends its PROSCAN facility with a third gantry treatment room - Gantry 3, which is realized in a research collaboration with Varian Medical Systems. The main research goals at the PROSCAN facility include further development of precise spot scanning and optimized beam delivery with low dead-time for treatment of moving targets. Consequently Gantry 3 is designed to feature advanced pencil beam scanning technology with a large scan field size of 30x40cm, integrated cone beam CT functionality and will in the future allow fast energy layer switching. The main challenge in realizing Gantry 3 is the integration of the Varian Gantry into the existing PROSCAN control system environment, allowing seamless beam operation. Installation of the additional treatment room has started in summer 2015 followed by the integration and technical commissioning phases of the Gantry in 2016, all during full operation of the existing treatment areas at our facility. We report about the special challenges and achieved performance results during commissioning of the Varian Gantry system in combination with the PSI PROSCAN facility.

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THPVA148

Inexpensive Brazeless RF Accelerator

gun, vacuum, cathode, electron

4812

S.P. Antipov, C.-J. Jing, R.A. Kostin, S.V. Kuzikov, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
A.A. Vikharev
IAP/RAS, Nizhny Novgorod, Russia

Funding: DOE SBIR
A simple, inexpensive way to manufacture a standard radio frequency (RF) driven particle accelerator is presented. The simplification comes from two innovations: utilization of LCLS gun - type RF design to avoid an expensive brazing process and copper plating of stainless steel that further reduces manufacturing cost. This is realized by a special structure design where accelerating structure cells are made out of copper plated stainless steel with knife edges and structure irises - copper disks acts also as gaskets for vacuum and RF seal. Besides the reduced cost, brazeless assembly allows integration of effective cooling and magnet optics elements into accelerator cells.

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FRYBA1

From Niels Bohr to Quantum Computing

coupling, controls, electron, factory

4852

K. Mølmer
AU, Aarhus, Denmark

The development and use of accelerators for research has been closely linked to an era of modern physics which of course includes quantum mechanics. Niels Bohr was one of the foreground figures in the development of quantum mechanics and the IPAC community would like to recognise his contributions to this field in 2017, when IPAC takes place in Copenhagen, where he was active. Quantum computing is a subject of enormous potential and interest, and we would like to hear about the historical links to Niels Bohr and the so called Copenhagen School of Quantum Mechanics, and what we realistically can expect from this development.

Slides FRYBA1 [2.490 MB]

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