IPAC2016 - List of Keywords (operation)

Paper	Title	Other Keywords	Page
MOOCA01	R&D of a Super-compact SLED System at SLAC	cavity, coupling, impedance, FEL	39
	J.W. Wang, G.B. Bowden, S. Condamoor, Y. Ding, V.A. Dolgashev, J.P. Eichner, M.A. Franzi, A.A. Haase, P. Krejcik, J.R. Lewandowski, S.G. Tantawi, L. Xiao, C. Xu SLAC, Menlo Park, California, USA
	Funding: Work supported by Department of Energy contract DE-AC03-76SF00515. We have successfully designed, fabricated, installed and tested a super-compact X-Band SLED system at SLAC. It is composed of an elegant mode converter/polarizer and a single sphere energy store cavity with high Q of 94000 and diameter less than 12 cm. The available RF peak power of 50 MW can be compressed to peak average power of more than 200 MW in order to double the kick for the electron bunches in a RF transverse deflector system and greatly improve the measurement resolution for both the electron bunch and the x-ray FEL pulse. High power operation has demonstrated the excellent performance of this RF compression system without any problems in RF breakdown, pulse heating and radiation. The design physics and fabrication as well as the measurement results will be presented in detail.
	Slides MOOCA01 [20.278 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOOCA01
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MOOCA03	Thyratron Replacement	klystron, network, linear-collider, electron	45
	I. Roth, M.P.J. Gaudreau, M.K. Kempkes Diversified Technologies, Inc., Bedford, Massachusetts, USA
	Funding: Work supported by DOE under contract DE-SC0011292 Semiconductor thyristors have long been used as a replacement for thyratrons in low power or long pulse RF systems. To date, however, such thyristor assemblies have not demonstrated the reliability needed for installation in short pulse, high peak power RF stations used with many pulsed electron accelerators. The fast rising current in a thyristor tends to be carried in a small region, rather than across the whole device, and this localized current concentration can cause a short circuit failure. An alternate solid-state device, the insulated-gate bipolar transistor (IGBT), can readily operate at the speed needed for the accelerator, but commercial IGBTs cannot handle the voltage and current required. It is, however, possible to assemble these devices in arrays to reach the required performance levels without sacrificing their inherent speed. Diversified Technologies, Inc. (DTI) has patented and refined the technology required to build these arrays of series-parallel connected switches. DTI is currently developing an affordable, reliable, form-fit-function replacement for the klystron modulator thyratrons at SLAC capable of pulsing at 360 kV, 420 A, 6 μs, and 120 Hz.
	Slides MOOCA03 [2.636 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOOCA03
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MOZB02	Challenges of the High Current Prototype Accelerator of IFMIF/EVEDA	rfq, linac, neutron, ion	52
	J. Knaster, Y. Okumura IFMIF/EVEDA, Rokkasho, Japan P. Cara Fusion for Energy, Garching, Germany A. Kasughai Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan M. Sugimoto QST/Takasaki, Takasaki, Japan
	LIPAc, under installation in Rokkasho will produce a 125 mA CW deuteron beam at 9 MeV. The objective of IFMIF is to generate a neutron flux of 10¹⁸ m-2s⁻¹ at 14 MeV for fusion materials testing using 2 x 125 mA CW D⁺ beams at 40 MeV impacting on a liquid lithium jet of 15 m/s. An ECR deuteron injector at 140 mA and 100 keV will be the source for a 9.7m long 4-vane RFQ, which will be complemented by a 175 MHz SRF linac composed of 8 HWRs for producing 9 MeV D⁺ beam. For a beam transmission >90%, beam simulations demand a D⁺ beam emittance below <0.3π mm·mrad. The first attempt on such high current accelerator was in the US in the early 80s under FMIT project with a H²⁺ 100 mA CW 2 MeV beam. LEDA successfully conducted 100 mA CW H⁺ at 6.7 MeV at the RFQ output energy in the late 90s, but using superconducting HWRs accelerating cavities at 125 mA CW with low-β H⁺/D⁺ beam has never been attempted. Beam halo will be monitored with 3 cryogenic μ-loss monitors azimuthally placed in each of the 8 superconducting solenoids interleaved with the HWR structures. A novel approach based on a beam core-halo dual matching has been developed to handle the MW range beam average power.
	Slides MOZB02 [18.358 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOZB02
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MOPMB002	First Measurements of Coherent Smith-Purcell Radiation in the SOLEIL Linac	detector, linac, radiation, experiment	69
	N. Delerue, J. Barros, S. Jenzer, V. Khodnevych, M.S. Malovytsia LAL, Orsay, France N. Hubert, M. Labat SOLEIL, Gif-sur-Yvette, France V. Khodnevych National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine M.S. Malovytsia KhNU, Kharkov, Ukraine
	Funding: The authors are grateful for the funding received from the French ANR (contract ANR-12-JS05-0003-01). An experiment to measure the Coherent Smith-Purcell radiation has been installed in the SOLEIL Linac. Its aim is to produce a map of Smith-Purcell radiation emissions in several planes and compare it with theoretical predictions. Coherent Smith Purcell radiation is produced when a grating is brought close from a sufficiently short charged particles beam. The experiment consist of two detectors with 5 degrees of freedom. These two detectors can be moved around the emission point to measure the intensity of the radiation at different locations. Radiation maps are recorded parasitically by moving the detectors around during normal linac operations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB002
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MOPMB009	Electron Beam Probe for the Bunch Length Measurements at BERLinPro	electron, diagnostics, simulation, gun	92
	D. Malyutin, A.N. Matveenko HZB, Berlin, Germany
	For the successful operation of various accelerator facilities a detailed bunch characterization is required. A complete description can be achieved using various diagnostic systems installed along an accelerator beamline. Ideally the diagnostic should be able to measure parameters of a single bunch in a non-destructive manner. For bunch length measurements this results in a complicated task especially for bunch duration below 1 ps. One of the possible solutions is a diagnostic based on the interaction of a low energy electron beam with electro-magnetic fields of the relativistic bunch. The bunch length can be readily deduced from the resulting scatter. In this paper bunch length measurement technique based on a low energy electron beam is introduced. Results of numerical simulations of measurements are presented. A possible setup of such diagnostic system for BERLinPro facility is proposed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB009
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MOPMB043	Preliminary Research of HLS II BLM System	storage-ring, vacuum, detector, site	190
	F.F. Wu, X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, J.G. Wang, Y.L. Yang, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China Y.K. Chen IHEP, Beijing, People's Republic of China
	Beam loss monitor system has been designed in many electron storages in order to indirectly measure lost electrons, which can be used to analysis beam loss mechanism and beam life. It can contribute to beam commissioning and improving stable operation of storage ring. According to lattice structure of the HLS II storage ring, 64 beam loss detectors have been located in the upper, lower, inner, outer side surfaces of vacuum chamber in the HLS II storage ring. Some preliminary researches based on the HLS II BLM system have been done. The results in successfully stable operation and unsuccessfully stable operation in beam commissioning stage were compared. Analysis of a sudden lost beam phenomenon were carried out.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB043
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MOPMB057	Automatic Microbeam Focusing for X-Ray Microbeam Experiments at the 4B Beamline of Pohang Light Source-II	focusing, controls, experiment, LabView	220
	K.H. Gil, H. J. Choi, J.-H. Lim PAL, Pohang, Republic of Korea
	The 4B beamline of the Pohang Light Source-II performs X-ray microdiffraction and microfluorescence experiments using X-ray microbeams. When performing X-ray micro-experiments, an X-ray microbeam should first be prepared. Up to recently, the microbeams with vertical and horizontal sizes (full width at half maximum) of less than 3 μm have been achieved, by manually adjusting the translations and pitch angles of the vertically and horizontally focusing mirrors, in a Kirkpatrick'Baez (K-B) mirror system. In this research, we developed a program that automates the complex and cumbersome process of microbeam focusing, divided into half-cutting and focusing phases. The developed program was applied to the 4B beamline and enabled the focusing of an X-ray beam to a minimum size within one hour. This paper introduces the algorithms of the program and also examines its performance.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB057
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MOPMR002	Bunch by Bunch Position Measurement and Analysis at PLS-II	injection, kicker, betatron, pick-up	232
	J. Lee, M.-H. Chun, I. Hwang, D.T. Kim, G. Kim, T.-Y. Lee, D.C. Shin, S. Shin PAL, Pohang, Republic of Korea
	Beam dynamic phenomena described by bunch-by-bunch motion are important issues for a storage ring and are described by various theoretical formalisms. Direct measurements of the beam position related to different dynamical mechanisms are a useful information to accelerator optimization. In PLS-II, 20 GHz sampling oscilloscope synchronized with injection event (or triggered by beam loss signal) is used to measure direct bunch by bunch motion. Based on the measured data, the principal component analysis had been performed to get the insight into beam dynamic phenomena such as couple bunch instability and beam oscillation due to kicker leakage. In this paper, we will describe the measurement method and the result of analysis for coupled bunch instability.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR002
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MOPMR013	Development, Calibration and Application of New-generation Dissectors with Picosecond Temporal Resolution	electron, laser, radiation, positron	251
	O.I. Meshkov, O. Anchugov, V.L. Dorohov, G.Y. Kurkin, A.V. Petrozhitskii, D.A. Shvedov, E.I. Zinin BINP SB RAS, Novosibirsk, Russia P.B. Gornostaev, M.Ya. Schelev, E.V. Shashkov, A. V. Smirnov, A.I. Zarovskii GPI, Moscow, Russia
	Funding: The presented experimental results were implemented due to financial support of the Russian Science Foundation (Projects N 14-29-00295) A dissector is an electron-optical device designed for measurement of periodic light pulses of subnanosecond and picosecond duration. LI-602 dissector developed at BINP is widely used for routine measurements of a longitudinal profile of electron and positron beams at BINP electron-positron colliders and other similar installations]. This dissector is a part of many optical diagnostic systems and provides temporal resolution of about 20 ps. Recently* a new generation of picosecond dissectors were created on the basis of the PIF-01/S1 picosecond streak-image tube designed and manufactured at the General Physics Institute Photoelectronics Department (Moscow). The device has demonstrated a temporal resolution of 3-4 ps (FWHM). The procedure of temporal resolution calibration and results of application of the new-generation picosecond dissector are given in this work. *E.I. Zinin, O.I. Meshkov. JINST, 2015 1748-0221 10 P10024 doi:10.1088/1748-0221/10/10/P10024
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR013
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MOPMR019	Beam Tests of a Prototype Stripline Beam Position Monitoring System for the Drive Beam of the CLIC Two-beam Module at CTF3	electronics, pick-up, impedance, vacuum	270
	A. Benot-Morell, A. Faus-Golfe IFIC, Valencia, Spain A. Benot-Morell, M. Wendt CERN, Geneva, Switzerland A. Faus-Golfe LAL, Orsay, France J.M. Nappa, S. Vilalte IN2P3-LAPP, Annecy-le-Vieux, France
	Funding: MINECO contract no. FPA2013-47883-C2-1-P. CLIC Collaboration Agreement, contract no. KE2638/BE. FNRA contract no. ANR-11-IDEX-0003-02. In collaboration with LAPP and IFIC, two units of a prototype stripline Beam Position Monitor (BPM) for the CLIC Drive Beam (DB), and its associated readout electronics have been successfully installed and tested in the Two-Beam-Module (TBM) at the CLIC Test Facility 3 (CTF3) at CERN. This paper gives a short overview of the BPM system and presents the performance measured under different Drive Beam configurations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR019
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MOPMR025	Beam Size Estimation from Luminosity Scans at the LHC During 2015 Proton Physics Operation	luminosity, emittance, proton, experiment	290
	M. Hostettler, G. Papotti CERN, Geneva, Switzerland M. Hostettler LHEP, Bern, Switzerland
	As a complementary method for measuring the beam size for high-intensity beams at 6.5 TeV flat-top energy, beam separation scans were done regularly at the CERN Large Hadron Collider (LHC) during 2015 proton physics operation. The luminosities measured by the CMS experiment during the scans were used to derive the convoluted beam size and orbit offset bunch-by-bunch. This contribution will elaborate on the method used to derive plane-by-plane, bunch-by-bunch emittances from the scan data, including uncertainties and corrections. The measurements are then compared to beam size estimations from absolute luminosity, synchrotron light telescopes, and wire scanners. In particular, the evolution of the emittance over the course of several hours in collisions is studied and bunch-by-bunch differences are highlighted.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR025
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MOPMR057	Measurements using Button BPM SUM Signal	electronics, storage-ring, beam-losses, insertion	377
	W.X. Cheng, K. Ha, J. Mead, O. Singh, G.M. Wang BNL, Upton, Long Island, New York, USA
	Modern digital BPM detectors measure not only the beam positions, four buttons SUM signal can be very helpful for machine developments and operations. At NSLS-II, BPM SUM signal has been used from commissioning stage, to investigate localized beam losses. During top-off operation, precise beam lifetime measurement within relative short period of time becomes important. With many BPMs along the ring, BPM SUM can be a much more accurate tool to measure the beam current and lifetime. BPM SUM signal shall be proportional to beam current, and it may depends on button sizes and BPM chamber geometry, cable attenuations, electronics attenuations, beam position, bunch lengths, fill pattern etc. Experience of BPM SUM signals measurements will be presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR057
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MOPMW003	Thermal Simulation of an Energy Feedback Normal Conducting RF Cavity	cavity, coupling, simulation, electron	396
	M. Fakhari, K. Flöttmann, S. Pfeiffer, H. Schlarb DESY, Hamburg, Germany J. Roßbach University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany A. Yahaghi CFEL, Hamburg, Germany
	Thermal simulation has been performed for an energy feedback normal conducting RF cavity. The cavity is going to be used as a fast actuator to regulate the arrival time of the electron bunches in fs level in FLASH. By measuring the arrival time jitter of one bunch in a bunch train, the designed cavity apply a correcting accelerating or decelerating voltage to the next bunches. The input power of the cavity is provided by a solid state amplifier and will be coupled to the cavity via a loop on the body. To achieve the fs level precision of the arrival time, the cavity should be able to provide accurate accelerating voltage with a precision of 300 eV. We performed thermal simulation to find out the temperature distribution of the cavity and make sure that heating will not affect its voltage precision. The simulation results show that by using two input loops the coupling constant will vary from 4.11 to 4.13 during the operation of the cavity which effect on the bunchs' arrival time would be less than 0.25 fs. While using just one input loop can lead to an error of about 1 fs.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW003
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MOPMW011	The Second Harmonic RF System for J-PARC MR Upgrade	cavity, impedance, injection, proton	420
	C. Ohmori, K. Hara, K. Hasegawa, M. Toda, M. Yoshii KEK, Tokai, Ibaraki, Japan M. Nomura, T. Shimada, F. Tamura, M. Yamamoto JAEA/J-PARC, Tokai-mura, Japan
	Power upgrade scenario of J-PARC Main Ring includes replacement of RF cavities with higher field gradient using magnetic alloy cores, FT3L than the present ones. It also need to install the second harmonic RF cavity in the other section where dedicated water system for RF cavities is not available. Installation scenario of the second harmonic RF will be presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW011
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MOPMW025	Vacuum RF Breakdown of Accelerating Cavities in Multi-Tesla Magnetic Fields	cavity, vacuum, Windows, electron	444
	D.L. Bowring, A. Moretti, M.A. Palmer, D.W. Peterson, A.V. Tollestrup, K. Yonehara Fermilab, Batavia, Illinois, USA B.T. Freemire IIT, Chicago, Illinois, USA A.V. Kochemirovskiy University of Chicago, Chicago, Illinois, USA P.G. Lane, Y. Torun Illinois Institute of Technology, Chicago, Illinois, USA
	Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359. Ionization cooling of intense muon beams requires the operation of high-gradient, normal-conducting RF structures within multi-Tesla magnetic fields. The application of strong magnetic fields has been shown to lead to an increase in vacuum RF breakdown. This phenomenon imposes operational (i.e. gradient) limitations on cavities in ionization cooling channels, and has a bearing on the design and operation of other RF structures as well, such as photocathodes and klystrons. We present recent results from Fermilab's MuCool Test Area (MTA), in which 201 and 805 MHz cavities were operated at high power both with and without the presence of multi-Tesla magnetic fields. We present an analysis of damage due to breakdown in these cavities, as well as measurements related to dark current and their relation to a conceptual model describing breakdown phenomena.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW025
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MOPMW026	Resonant Control for Fermilab's PXIE RFQ	rfq, controls, resonance, cavity	447
	D.L. Bowring, B.E. Chase, J. Czajkowski, J.P. Edelen, D.J. Nicklaus, J. Steimel, T.J. Zuchnik Fermilab, Batavia, Illinois, USA S. Biedron, A.L. Edelen, S.V. Milton CSU, Fort Collins, Colorado, USA
	Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359. The RFQ for Fermilab's PXIE test program is designed to accelerate a < 10 mA H⁻ CW beam to 2.1 MeV. The RFQ has a four-vane design, with four modules brazed together for a total of 4.45 m in length. The RF power required is < 130 kW at 162.5 MHz. A 3 kHz limit on the maximum allowable frequency error is imposed by the RF amplifiers. This frequency constraint must be managed entirely through differential cooling of the RFQ's vanes and outer body and associated material expansion. Simulations indicate that the body and vane coolant temperature should be controlled to within 0.1 degrees C. We present the design of the cooling network and the resonant control algorithm for this structure, as well as results from initial operation.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW026
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MOPMW028	Progress on the MICE RF Module at LBNL	cavity, vacuum, coupling, experiment	454
	T.H. Luo, A.J. DeMello, A.R. Lambert, D. Li, T.J. Loew, S. Prestemon, S.P. Virostek, J.G. Wallig LBNL, Berkeley, California, USA T.G. Anderson, A.D. Bross, M.A. Palmer Fermilab, Batavia, Illinois, USA Y. Torun IIT, Chicago, Illinois, USA
	The international Muon Ionization Cooling Experiment aims to demonstrate the transverse cooling of a muon beam by ionization in energy absorbers. The final MICE cooling channel configuration has two RF modules, each housing a 201 MHz RF cavity used to compensate the longitudinal energy loss in the absorbers. The assembly of MICE RF Module is being carried out at LBL. In this paper we will report the recent progress on the assembly work.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW028
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MOPMW032	Study of RF Breakdown in 805MHz Pillbox Modular Cavity in Strong Magnetic Field	cavity, radiation, site, pick-up	466
	A.V. Kochemirovskiy University of Chicago, Chicago, Illinois, USA D.L. Bowring, A. Moretti, K. Yonehara Fermilab, Batavia, Illinois, USA B.T. Freemire IIT, Chicago, Illinois, USA Y. Torun Illinois Institute of Technology, Chicago, Illlinois, USA
	RF breakdown has a negative impact on a cavity's performance, especially with the presence of strong magnetic fields. This issue can arise in designs of muon ionization cooling channel, RF guns, klystrons and in many other applications. The MuCool Test Area at Fermilab is the facility that allows us to study the effects of static magnetic field on RF cavity operation. As a part of this research program, we have tested an 805MHz pillbox "modular" cavity in strong external magnetic fields. The design of the cavity allowed for a better control over sources of systematic error. "Modular" structure of the cavity enables easy dismounting of the endplates to perform inspection of inner surfaces after each run as well as swapping endplates to study the effects of various materials on breakdown phenomenon. Coupler design ensures maximum electric field enhancement on cavity axis, thus reducing breakdown probability in the coupler region. The results and analysis from high-power runs with zero and non-zero external magnetic fields will be presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW032
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MOPMW034	Final Commissioning of the MICE RF Module Prototype with Production Couplers	cavity, vacuum, coupling, Windows	474
	Y. Torun, P.G. Lane Illinois Institute of Technology, Chicago, Illlinois, USA T.G. Anderson, M. Backfish, D.L. Bowring, A. Moretti, D.V. Neuffer, D.W. Peterson, M. Popovic, K. Yonehara Fermilab, Batavia, Illinois, USA B.T. Freemire IIT, Chicago, Illinois, USA T.L. Hart UMiss, University, Mississippi, USA A.V. Kochemirovskiy University of Chicago, Chicago, Illinois, USA T.H. Luo LBNL, Berkeley, California, USA
	Funding: Supported by the US Department of Energy Office of Science through the Muon Accelerator Program. We report operational experience from the prototype RF module for the Muon Ionization Cooling Experiment (MICE) with final production couplers at Fermilab's MuCool Test Area. This is the last step in fully qualifying the RF modules for operation in the experiment at RAL.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW034
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MOPMY007	Mechanical Design and 3-D Coupled RF, Thermal-Structural Analysis of Normal Conducting 704 MHz and 2.1 GHz Cavities for LEReC Linac	cavity, simulation, vacuum, software	525
	J.C. Brutus, S.A. Belomestnykh, I. Ben-Zvi, M. Blaskiewicz, J.M. Brennan, A.V. Fedotov, M.C. Grau, C. Pai, L. Snydstrup, J.E. Tuozzolo, B. P. Xiao, T. Xin, W. Xu, A. Zaltsman BNL, Upton, Long Island, New York, USA V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE. Two normal conducting cavities operating at 704 MHz and 2.1 GHz will be used for the Low Energy RHIC electron Cooling (LEReC) under development at BNL to improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon. The single cell 704 MHz cavity and the 3-cell 2.1 GHz third harmonic cavity will be used in LEReC to correct the energy spread introduced in the SRF cavity. The successful operation of normal RF cavities has to satisfy both RF and mechanical requirements. 3-D coupled RF-thermal-structural analysis has been performed on the cavities to confirm the structural stability and to minimize the frequency shift resulting from thermal and structural expansion. In this paper, we will present an overview of the mechanical design, results from the RF-thermal-mechanical analysis, progress on the fabrication and schedule for the normal conducting RF cavities for LEReC.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY007
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MOPMY013	Design Study of Collector for CEPC 650 MHz Klystron	gun, klystron, simulation, interface	540
	S.C. Wang, D.D. Dong, S. Fukuda, G. Pei, O. Xiao, .. Zaib-un-Nisa, Z.S. Zhou IHEP, Beijing, People's Republic of China S. Fukuda KEK, Ibaraki, Japan
	This paper presents the design and simulation of collector for CEPC 650 MHz high-power CW klystron. Power dissipation in collector is optimised by universal beam spread curve using EGUN code, and beam trajectory in collector is verified by Magic code. The thermal analysis is done by ANSYS-CFX, and groove number and water flow rate are optimized by fluid-solid coupled heat transfer simulation.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY013
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MOPMY027	Preliminary Design of High-efficiency Klystron for Pohang Accelerator Laboratory (PAL)	cavity, klystron, beam-losses, simulation	557
	S.J. Park, J.Y. Choi, Y.D. Joo, K.R. Kim, W. Namkung, C.D. Park PAL, Pohang, Kyungbuk, Republic of Korea M.-H. Cho, J.H. Hwang, T. Seong POSTECH, Pohang, Kyungbuk, Republic of Korea
	Funding: Supported by the Ministry of Science, ICT and Future Planning of Korea. Klystrons for particle accelerators are typically designed to have narrow bandwidths with center frequencies ranging from several hundreds (e.g., 350) MHz to X-band (11.424 GHz). Output powers are from several tens of kW to ~1 MW for CW klystrons and ~100 MW for pulsed ones. The narrow-bandwidth requirement has enabled them to provide high gain (typically 40 - 50 dB) which greatly simplifies the RF drive system. Recently, especially for large-scale accelerator facilities, the klystron efficiency has become one of the most demanding issues. This is because electricity cost occupies a great portion of their operating budgets and the klystron efficiency is one of the important factors determining the electricity consumption of the whole accelerator system. In this regard, we have designed a high-efficiency klystron for use in the PLS-II and PAL XFEL at PAL. The basic scheme is to re-design the cavity system to include multi-cell output cavity. In this article, we report on our preliminary design work to determine major cavity parameters including cell frequencies, inter-cell distances, and coupling to external circuits (coupling beta).
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY027
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MOPMY031	Development of a 500 MHz Solid-state RF Amplifier as a Combination of Ten Modules	status, interface, rf-amplifier, factory	563
	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
	The recent development of semiconductor technology has proved that a solid-state RF amplifier is an attractive alternative high-power RF source for numerous accelera-tor applications. Because of the great redundancy and reliability of solid-state amplifiers present in many facili-ties worldwide, the development of a kW-level RF power per module using compact planar baluns has also been undertaken in NSRRC. Ten amplifier modules are com-bined to achieve stable output power 8 kW as an initial conceptual realization of a basic power unit within a combined network. This article describes each portion of the amplifier with the experimental results.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY031
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MOPMY037	GaN Class-F Power Amplifier for Klystron Replacement	klystron, vacuum, electron, controls	583
	A.V. Smirnov RadiaBeam Systems, Santa Monica, California, USA R.B. Agustsson, S. Boucher, D.I. Gavryushkin, J.J. Hartzell, K.J. Hoyt, A.Y. Murokh, T.J. Villabona RadiaBeam, Santa Monica, California, USA
	Funding: This work was supported by the U.S. Department of Energy (award No. DE-SC0013136) The vacuum-tube-based RF amplifiers are relatively inefficient and becoming obsolete as the RF world has been progressively converting to solid state technology. Currently, the JLAB upgrade program requires 340 amplifiers capable of 8 kW CW at 1497 MHz while operating at more than 55-60% efficiency to replace their klystrons. Here we explore the possibility of a klystron replacement employing high electron mobility packaged GaN transistors applied in an array of Class-F amplifiers. The inputs and outputs of the many modules needed to make a complete amplifier are connected via precise, in-phase, low-loss, broadband, combiners-dividers. We describe early prototypes of the amplifiers as well as the combiners-dividers and discuss the design features and challenges of such a scheme. This approach can be applied to other national facilities and also for replacement of the klystrons in Middle Energy Electron-Ion Collider which requires about 1.8 MW CW power in total to be produced at 952.6 MHz frequency including 2x12.5 kW power for "crabbing" and 0.53 MW for electron cooling.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY037
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MOPOR008	Beam Induced RF Heating in LHC in 2015	impedance, injection, vacuum, monitoring	602
	B. Salvant, O. Aberle, M. Albert, R. Alemany-Fernandez, G. Arduini, J. Baechler, M.J. Barnes, P. Baudrenghien, O.E. Berrig, N. Biancacci, G. Bregliozzi, J.V. Campelo, F. Carra, F. Caspers, P. Chiggiato, A. Danisi, H.A. Day, M. Deile, D. Druzhkin, J. F. Esteban Müller, S. Jakobsen, J. Kuczerowski, A. Lechner, R. Losito, A. Masi, N. Minafra, E. Métral, A.A. Nosych, A. Perillo Marcone, D. Perini, S. Redaelli, F. Roncarolo, G. Rumolo, E.N. Shaposhnikova, J.A. Uythoven, C. Vollinger, A.J. Välimaa, N. Wang, M. Wendt, J. Wenninger, C. Zannini CERN, Geneva, Switzerland M. Bozzo INFN Genova, Genova, Italy J.F. Esteban Müller EPFL, Lausanne, Switzerland N. Wang IHEP, Beijing, People's Republic of China
	Following the recurrent beam induced RF issues that perturbed LHC operation during LHC Run 1, a series of actions were put in place to minimize the risk that similar issues would occur in LHC Run 2: longitudinal impedance reduction campaign and/or improvement of cooling for equipment that were problematic or at the limit during Run 1, stringent constraints enforced on new equipment that would be installed in the machine, tests to control the bunch length and longitudinal distribution, additional monitoring of temperature, new monitoring tools and warning chains. This contribution reports the outcome of these actions, both successes as well as shortcomings, and details the lessons learnt for the future runs.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR008
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MOPOR010	Impedance Measurements and Simulations on the TCTP and TDI LHC Collimators	impedance, HOM, simulation, embedded	610
	N. Biancacci, F. Caspers, A. Grudiev, J. Kuczerowski, I. Lamas Garcia, A. Lechner, E. Métral, A. Passarelli, A. Perillo Marcone, B. Salvant, J.A. Uythoven CERN, Geneva, Switzerland O. Frasciello, M. Zobov INFN/LNF, Frascati (Roma), Italy A. Mostacci Rome University La Sapienza, Roma, Italy N. Mounet EPFL, Lausanne, Switzerland
	The LHC collimation system is a critical element for the safe operation of the LHC machine and is subject to continuous performance monitoring, hardware upgrade and optimization. In this work we will address the impact on impedance of the upgrades performed on the TDI injection protection collimator, where the absorber material has been changed to mitigate the device heating observed in machine operation, and on selected secondary (TCS) and tertiary (TCT) collimators, where beam position monitors (BPM) have been embedded for faster jaw alignment. Concerning the TDI, we will present the RF measurements performed before and after the upgrade, comparing the result to heating and tune shift beam measurements. For the TCTs, we will study how the higher order modes (HOM) introduced by the BPM addition have been cured by means of ferrite placement in the device. The impedance mitigation campaign has been supported by RF measurements whose results are in good agreement with GdfidL and CST simulations. The presence of undamped low frequency modes is proved not to be detrimental to the safe LHC operation.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR010
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MOPOR022	Beam Dynamics Observations of the 2015 High Intensity Scrubbing Runs at the Cern Sps	electron, octupole, injection, emittance	648
	H. Bartosik, G. Iadarola, K.S.B. Li, L. Mether, A. Romano, G. Rumolo, M. Schenk CERN, Geneva, Switzerland
	Beam quality degradation caused by e-cloud effects has been identified as one of the main performance limitations for high intensity LHC beams with 25 ns bunch spacing in the SPS. In view of the beam parameters targeted with the LHC injectors upgrade (LIU) project, about two weeks of SPS machine time in 2015 were devoted to dedicated scrubbing runs with high intensity LHC 25 ns and dedicated 'doublet' beams in order to study the achievable reduction of e-cloud effects and quantify the consequent beam performance improvements. This paper describes the main observations concerning the coherent instabilities and beam dynamics limitations encountered as well as a detailed characterisation of the performance reach with the highest beam intensity presently available from the pre-injectors.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR022
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MOPOW001	Status of the 1.3 GeV Booster Synchrotron for Generating High Energy Gamma Rays at Tohoku University	vacuum, controls, dipole, booster	701
	F. Hinode, H. Hama, S. Kashiwagi, T. Muto, I. Nagasawa, K. Nanbu, Y. Shibasaki, K. Takahashi, C. Tokoku Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	The reconstruction work of accelerator complex for the Great East Japan Earthquake in March 2011 had been conducted in Research Center of Electron Photon Science, Tohoku University. Since restoration of the user machine time in 2013, the approved beam time have been regularly implemented as scheduled. Currently, the 1.3 GeV Booster STorage (BST) ring has been well utilized to generate the high energy gamma-rays as before the disaster. The high energy gamma-rays were produced via Bremsstrahlung by inserting an internal target wire to the beam orbit after the beam acceleration. Since the user machine time was recovered, there were some improvements so far, i.e. realignment of synchrotron magnets, orbit correction in energy ramping process by updating the control of power supplies for steering magnets etc., which brought an increase of the beam current in the maximum energy. Present operational status and recent progress of beam performance in the BST ring are reported.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW001
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MOPOW007	Parts Tracking for Fabrication, Installation and Maintenance at the European XFEL	status, database, controls, monitoring	719
	L. Hagge, J.A. Dammann, A. Frank, J. Kreutzkamp, D. Käfer, B. List, S. Rohwedder DESY, Hamburg, Germany
	DESY has established a powerful configuration management solution for the construction of the European XFEL. It tracks the status and location of accelerator components during fabrication and installation, and it contains workflows for reviews, change control and the handling of non-conformities. It provides extensive progress monitoring and reporting for the production and installation of accelerator components. This way, it collects on-the-fly a comprehensive documentation of the accelerator, which serves as a thorough foundation for asset and maintenance management during the upcoming operation. The poster gives an overview of the application and summarizes its status, benefits and experience.
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MOPOW010	The Superconducting Soft X-ray Free-Electron Laser User Facility FLASH	FEL, photon, laser, electron	729
	M. Vogt, J. Feldhaus, K. Honkavaara, J. Rönsch-Schulenburg, S. Schreiber, R. Treusch DESY, Hamburg, Germany
	FLASH, the superconducting free-electron laser at DESY delivers up to several thousand photon pulses per second with wavelengths ranging from 52 nm down to as low as 4.2 nm and with pulse energies of up to 500 uJ to photon users at the FLASH1 beamline. In 2014 and 2015 a second beamline, FLASH2, has been commissioned in parallel to user operation at FLASH1. FLASH produces bunch trains of up to 800 bunches in 0.8 ms with a train repetition rate of 10 Hz. Each train can be split in sub-trains for FLASH1 and FLASH2, such that both beamlines receive bursts of bunches with full 10 Hz. Operational highlights are the latest SASE energy record of 600 uJ at 15 nm in FLASH2, and the first simultaneous SASE lasing of three undulator systems: FLASH1 (13.7 nm), sFLASH (38 nm), and FLASH2 (20 nm). sFLASH is the seeding experiment in the FLASH1 beamline. Moreover we will report on recent technical and operational improvements. A major success is the improved reliability and stability of the whole facility with shorter SASE tuning times.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW010
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MOPOW015	Fermi Upgrade Plans	FEL, laser, electron, linac	744
	A. Fabris, E. Allaria, L. Badano, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, F. Cilento, P. Cinquegrana, M. Coreno, R. Cucini, I. Cudin, G. D'Auria, M.B. Danailov, R. De Monte, G. De Ninno, P. Delgiusto, A.A. Demidovich, S. Di Mitri, B. Diviacco, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, P. Finetti, P. Furlan Radivo, G. Gaio, D. Gauthier, F. Gelmetti, L. Giannessi, F. Iazzourene, M. Kiskinova, S. Krecic, M. Lonza, N. Mahne, M. Malvestuto, C. Masciovecchio, M. Milloch, F. Parmigiani, G. Penco, A. Perucchi, L. Pivetta, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, P. Rebernik Ribič, F. Rossi, E. Roussel, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, M. Svandrlik, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	FERMI has reached its nominal performance on both FEL lines, FEL-1 (12 eV to 62 eV) and FEL-2 (62 eV to 310 eV). After a brief overview of the activities with users, we will describe plans for LINAC , FEL and beamline upgrades for 2016-2018 and beyond. This includes EEHG schemes for FEL-2.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW015
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MOPOW018	Feasibility Study of Photocathode Opearation of Thermionic RF Gun at KU-FEL	FEL, cathode, electron, gun	754
	H. Zen, T. Kii, K. Masuda, K. Morita, T. Murata, T. Nogi, H. Ohgaki, S. Suphakul, K. Torgasin Kyoto University, Kyoto, Japan R. Kuroda AIST, Tsukuba, Ibaraki, Japan
	Kyoto University Free Electron Laser (KU-FEL) is a mid-infrared FEL driven by a compact linac utilizinig a thermionic RF gun as its electron source. Recently we succeeded in operating KU-FEL with photocathode operation of the RF gun by using the thermionic cathode (LaB6) as a photocathode. The performance of KU-FEL under the thermionic cathode and photocathode operation will be reported. In addition, some recent application experiment results will also be presented in this presentation. H. Zen, et al., Infrared Phys. Techn. 51 (2008) 382.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW018
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MOPOW054	The 4th Harmonic Cavity for Hefei Light Source-II	cavity, HOM, storage-ring, synchrotron	837
	C.-F. Wu, S. Dong, G. Huang, D. Jia, K. Jin, C. Li, J.Y. Li, W. Li, J.G. Wang, L. Wang, W. Xu, K. Xuan USTC/NSRL, Hefei, Anhui, People's Republic of China R.A. Bosch UW-Madison/SRC, Madison, Wisconsin, USA G.Y. Kurkin, E. Rotov BINP SB RAS, Novosibirsk, Russia G. Ya Budker Institute of Nuclear Physics, Novosibirsk, Russia
	The 4th harmonic cavity has been firstly used in the storage ring for HLS-II. The paper presents the physics design, developing process and the experimental results for commision. The measurment results show that rf parameters are reasonable. The 4th harmonic cavity efficiently lengthen the bunch and increase the beam life-time. Specially, the beam instablity has been supressed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW054
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MOPOY006	Preparations for Upgrading the RF Systems of the PS Booster	cavity, impedance, feedback, emittance	853
	S.C.P. Albright, D. Quartullo, E.N. Shaposhnikova CERN, Geneva, Switzerland
	The accelerators of the LHC injector chain need to be upgraded to provide the HL-LHC beams. The PS Booster, the first synchrotron in the LHC injection chain, uses three different RF systems (first, second and up to tenth harmonic) in each of its four rings. As part of the LHC Injector Upgrade the current ferrite RF systems will be replaced with broadband Finemet cavities, increasing the flexibility of the RF system. A Finemet test cavity has been installed in Ring 4 to investigate its effect on machine performance, especially beam stability, during extensive experimental studies. Due to large space charge impedance Landau damping is lost through most of the cycle in single harmonic operation, but is recovered when using the second harmonic and controlled longitudinal emittance blow-up. This paper compares beam parameters during acceleration with and without the Finemet test cavity. Comparisons were made using beam measurements and simulations with the BLonD code based on a full PS Booster impedance model. This work, together with simulations of future operation, have provided input for the decision to adopt a fully Finemet RF system.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY006
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MOPOY010	Simulations and Measurements of Stopbands in the Fermilab Recycler	simulation, resonance, space-charge, proton	864
	R. Ainsworth, P. Adamson, K.J. Hazelwood, I. Kourbanis, E.G. Stern Fermilab, Batavia, Illinois, USA
	Fermilab has recently completed an upgrade to the complex with the goal of delivering 700 kW of beam power as 120 GeV protons to the NuMI target. A major part of boosting beam power is to use the Fermilab Recycler to stack protons. Simulations focusing on the betatron resonance stopbands are presented taking into account different effects such as intensity and chromaticity. Simulations are compared with measurements.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY010
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MOPOY017	Upgrade of the Universal Linear Accelerator UNILAC for FAIR	DTL, ion, emittance, rfq	880
	L. Groening, A. Adonin, X. Du, R. Hollinger, E. Jäger, M.T. Maier, S. Mickat, A. Rubin, B. Schlitt, G. Schreiber, H. Vormann, C. Xiao, A. Yakushev, C. Zhang GSI, Darmstadt, Germany M. Baschke, H. Hähnel, H. Podlech, U. Ratzinger, A. Seibel, R. Tiede IAP, Frankfurt am Main, Germany Ch.E. Düllmann, P. Scharrer HIM, Mainz, Germany
	In order to meet the requirements on beam parameters for the upcoming FAIR facility at GSI, the injector linac UNILAC will be upgraded. The activities comprise development of the sources for stable provision of intense uranium beams at a repetition rate of 2.7 Hz, a revision of the beam dynamics layout of the 120 keV/u RFQ, the replacement of the matching section to the 1.4 MeV/u pre-stripper DTL, and enhancement of the gaseous stripping section efficiency. This section shall also include a round-to-flat emittance adaptor to prepare the beam for injection into the synchrotron SIS18 which has a flat transverse injection acceptance. Finally, the upgrade includes the complete replacement of the 40 year old 11.4 MeV/u Alvarez-type post-stripper DTL with a new DTL, preferably using Alvarez-type cavities with improved beam focusing features, as well as its rf-power alimentations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY017
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MOPOY019	Status of the First CH-Cavities for the New Superconducting CW Heavy Ion LINAC@GSI	resonance, cavity, linac, ion	886
	M. Basten, M. Amberg, M. Busch, F.D. Dziuba, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany K. Aulenbacher IKP, Mainz, Germany K. Aulenbacher, W.A. Barth, V. Gettmann, S. Mickat, M. Miski-Oglu HIM, Mainz, Germany W.A. Barth, M. Heilmann, S. Mickat, S. Yaramyshev GSI, Darmstadt, Germany
	In the field of Super Heavy Elements (SHE) a superconducting (sc) continuous wave (cw) high intensity heavy ion LINAC is highly desirable. Currently a multi-stage R&D program conducted by GSI, HIM and IAP* is in progress. The baseline linac design composes a high performance ion source, a new low energy beam transport line, a (cw) upgraded High Charge State Injector (HLI), and a matching line (1.4 MeV/u) followed by the new sc-DTL LINAC for acceleration up to 7.3 MeV/u. The commissioning of the first CH cavity (Demonstrator), in a horizontal cryo module with beam is a major milestone in 2016*. The advanced demonstrator comprises constant-beta sc Crossbar-H-mode (CH) cavities operated at 217 MHz. Presently, the first two sc CH cavities of the advanced demonstrator are under construction at Research Instruments (RI), Bergisch Gladbach, Germany. A string of cavities and focusing elements build from several short CH-cavities with 8 gaps, without girders is recommended. The new design potentially reduces the overall technical risks during the fabrication and the pressure sensitivity through stiffening brackets. The present status of the first two sc cavities will be presented. W.Barth et al., Further R&D for a new Superconducting cw Heavy Ion LINAC@GSI, IPAC'14 **F.Dziuba et al., Measurements on the Superconducting 217 MHz CH Cavity during the Manufacturing Phase, SRF2015
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY019
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MOPOY020	Prototype Design of a Newly Revised CW RFQ for the High Charge State Injector at GSI	rfq, simulation, resonance, impedance	889
	D. Koser, H. Podlech IAP, Frankfurt am Main, Germany P. Gerhard, L. Groening, O.K. Kester GSI, Darmstadt, Germany
	Within the scope of the FAIR project (Facility for Antiproton and Ion Research) at GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, the front end of the existing High Charge State Injector (HLI) is planned to be upgraded for cw operation. The required newly revised 4-Rod RFQ structure is currently being designed at the Institute for Applied Physics (IAP) of the Goethe University of Frankfurt. It will be operated with a 100 kW power amplifier at 108 MHz. At first instance a dedicated 4-stem prototype, which is based on the RFQ design for MYRRHA* and FRANZ*, is planned to be manufactured in order to validate the simulated RF performance, thermal behavior and mechanical characteristics in continuous operation. The RF simulations as well as basic thermal simulations are done using CST Studio Suite. In order to prevent oscillations of the electrodes mechanical eigenmodes are analyzed using ANSYS Multiphysics. In addition the ANSYS software allows more sophisticated simulations regarding the cooling capability by considering fluid dynamics in water cooling channels, thus providing a more detailed thermal analysis. C. Zhang, H. Podlech, New Reference Design of the European ADS RFQ Accelerator For MYRRHA, IPAC2014 **M. Heilmann et al., A Coupled RFQ-IH Cavity for the Neutron Source FRANZ, IPAC2013
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY020
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MOPOY048	A Novel Approach in the One-Dimensional Phase Retrieval Problem and its Application to the Time Profile Reconstruction	electron, optics, FEL, laser	955
	F. Bakkali Taheri, J. Cowley, G. Doucas, S.M. Hooker, I.V. Konoplev JAI, Oxford, United Kingdom R. Bartolini DLS, Oxfordshire, United Kingdom
	Funding: This work was supported (in parts) by the UK Science and Technology Facilities Council (STFC UK) grant ST/M003590/1 and The Leverhulme Trust through International Network Grant IN-2015-012 Accurate knowledge of the longitudinal profile of the bunch is important in the context of linear colliders, wake-field accelerators and for the next generation of light sources. As a result the non-destructive, single-shot evaluation of the profile is one of the challenging problems which can be addressed via spectral analysis of coherent radiation generated by a charged particle bunch. To reconstruct the bunch profile from the spectrum the phase retrieval problem has to be solved. Frequently applied methods, e.g. minimal phase retrieval or other iterative algorithms, are reliable if the Blaschke phase contribution is negligible. This is neither known a priori nor can it be assumed to apply to an arbitrary bunch profile. We present a novel approach which gives reproducible, most-probable and stable reconstructions for bunch profiles that would otherwise remain unresolved by the existing techniques. The algorithm proposed uses the output of Kramers-Kronig minimum phase as both initial and boundary conditions, providing a unique solution. To assure a converging solution, new conditions linked to the independently known experimental data such as beam charge were introduced.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY048
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MOPOY050	Beam Commissioning Plan of the FRIB Superconducting Linac	linac, cavity, optics, simulation	961
	Y. Zhang, C.P. Chu, Z.Q. He, M. Ikegami, S.M. Lidia, S.M. Lund, F. Marti, G. Shen, Y. Yamazaki, Q. Zhao FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 The FRIB superconducting linac will deliver all heavy ion beams with energy above 200 MeV/u, and beam power on target up to 400 kW for generation of short lived isotopes. Beam commissioning is the first step to prepare and tune the superconducting linac for high power operation. A staged beam commissioning plan of the FRIB linac is developed, and complete beam tuning practices segment by segment through the entire linac are introduced, which include phase scan signature matching of the superconducting cavities, longitudinal beam matching, transverse matching with horizontal-vertical beam coupling, and beam optics corrections of achromatic and isochronous folding segments up to the second order for acceleration and transport of multi charge state beams.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY050
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MOPOY054	Status of the ESS RFQ	rfq, vacuum, cavity, status	974
	D. Chirpaz-Cerbat, A. Albéri, A.C. Chauveau, M. Lacroix, N. Misiara, G. Perreu, O. Piquet, H. Przybilski, N. Sellami CEA/IRFU, Gif-sur-Yvette, France N. Berton, G. Bourdelle, M. Desmons, A.C. France, V.M. Hennion, P.-A. Leroy, B. Pottin CEA/DSM/IRFU, France
	The ESS Radio-Frequency Quadrupole (RFQ) is a 4-vanes resonant cavity designed at the frequency of 352.21 MHz. It must accelerate and bunch a 70mA proton beams from 75keV to 3.62MeV with a 4% duty cycle. The RFQ design has already been done, and documented in other papers. This one will present the global status of the RFQ, with technical solutions cho-sen for the main components (for fabrication and op-eration) and the present status of the RFQ fabrication.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY054
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TUXA01	Status and Future Upgrade of J-PARC Accelerators	linac, injection, extraction, hadron	999
	M. Kinsho JAEA/J-PARC, Tokai-mura, Japan
	The linac energy reached to 400 MeV as a design value and also a beam current was upgraded to 50 mA by replacing a new ion source. At the 3 GeV synchrotron, a high power beam of 8.41x10¹³ protons per pulse was demonstrated, which was equivalent to 1 MW when the repetition would be 25 Hz. At the main ring, beam loss was reduced by suppression of transverse instabilities and so on. The beam power for both the neutrino experiment and hadron experimental facility is increasing to reduce beam loss. J-PARC accelerators each have their own upgrade plan to increase beam power. The progress and future plan of J-PARC accelerators are reported in this paper.
	Slides TUXA01 [11.427 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUXA01
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TUOAA01	Operation of LANSCE Linear Accelerator with Double Pulse Rate and Low Beam Losses	beam-losses, linac, DTL, proton	1004
	Y.K. Batygin, J.S. Kolski, R.C. McCrady, L. Rybarcyk LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by US DOE under contract DE-AC52-06NA25396 In 2014 LANSCE accelerator facility return to 120 Hz pulse rate operation after long period of operation at 60 Hz pulse rate. Increased capabilities require careful tuning of all components of linear accelerator. Transformation to double pulse rate resulted in re-evaluation of tuning procedures in order to meet new challenges in beam operation. The paper summarizes experimental activity on sustaining of high productivity of accelerator facility while keeping beam losses along accelerator at the low level.
	Slides TUOAA01 [14.886 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOAA01
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TUOAA02	Status and Performance of ORNL Spallation Neutron Source Accelerator Systems	linac, rfq, ion-source, ion	1007
	Y.W. Kang, A.V. Aleksandrov, D.E. Anderson, M.S. Champion, M.T. Crofford, J. Galambos, B. Han, S.-H. Kim, S.W. Lee, J. Moss, V.V. Peplov, C. Piller, M.A. Plum, R.T. Roseberry, J.P. Schubert, A.P. Shishlo, M.P. Stockli, C.M. Stone, R.F. Welton, M. Wezensky, D.C. Williams, A.P. Zhukov ORNL, Oak Ridge, Tennessee, USA L.A. Longcoy, M. Magda, M.E. Middendorf, W.S. Passmore, C.C. Peters, J. Price, R.B. Saethre, J. Saunders ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. The Spallation Neutron Source (SNS) accelerator sys-tems have been performing continuously and progressively since commissioning in 2006 to deliver the neutrons to beamlines. The 1.4 MW design beam power has been demonstrated during 24/7 operation while developments and investigations for system improvements are still ongoing to achieve the full design beam power and availability. Numerous difficulties that impeded reaching the full performance of the SNS accelerator systems have been identified and are being eliminated through repairs, upgrades, and developments. In this report, operational performance and developments of the accelerator systems are presented along with the efforts for future upgrades of the SNS.
	Slides TUOAA02 [5.410 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOAA02
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TUOBA02	ER@CEBAF - A High Energy, Multi-pass Energy Recovery Experiment at CEBAF	linac, experiment, optics, electron	1022
	F. Méot, I. Ben-Zvi, Y. Hao, P. Korysko, C. Liu, M.G. Minty, V. Ptitsyn, G. Robert-Demolaize, T. Roser, P. Thieberger, N. Tsoupas BNL, Upton, Long Island, New York, USA M.E. Bevins, S.A. Bogacz, D. Douglas, C.J. Dubbe, T.J. Michalski, F.C. Pilat, Y. Roblin, T. Satogata, M. Spata, C. Tennant, M.G. Tiefenback JLab, Newport News, Virginia, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. A high-energy, multiple-pass energy recovery (ER) experiment proposal, using CEBAF, is in preparation by a JLab-BNL collaboration. The experiment will be proposed in support of the electron-ion collider project (EIC) R&D going on at BNL. This new experiment extends the 2003, 1-pass, 1 GeV CEBAF-ER demonstration into a range of energy and recirculation passes commensurate with BNL's anticipated linac-ring EIC parameters. The experiment will study ER and recirculating beam dynamics in the presence of synchrotron radiation, provide opportunity to develop and test multiple-beam diagnostic instrumentation, and can also probe BBU limitations. This paper gives an overview of the ER@CEBAF project, its context and preparations.
	Slides TUOBA02 [1.936 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOBA02
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TUOCA01	LCLS Bunch Compressor Configuration Study for Soft X-ray Operation	bunching, electron, laser, linac	1037
	S. Li, Y. Ding, Z. Huang, A. Marinelli, T.J. Maxwell, D.F. Ratner, F. Zhou SLAC, Menlo Park, California, USA C. Behrens DESY, Hamburg, Germany
	The microbunching instability (MBI) is a well-known problem for high brightness electron beams and has been observed at accelerator facilities around the world. Free-electron lasers (FELs) are particularly susceptible to MBI, which can distort the longitudinal phase space and increase the beam's slice energy spread (SES). Past studies of MBI at the Linac Coherent Light Source (LCLS) relied on optical transition radiation to infer the existence of microbunching. With the development of the x-band transverse deflecting cavity (XTCAV), we can for the first time directly image the longitudinal phase space at the end of the accelerator and complete a comprehensive study of MBI, revealing both detailed MBI behavior as well as insights into mitigation schemes [1]. The fine time resolution of the XTCAV also provides the first LCLS measurements of the final SES, a critical parameter for many advanced FEL schemes. Detailed MBI and SES measurements can aid in understanding MBI mechanisms, benchmarking simulation codes, and designing future high-brightness accelerators.
	Slides TUOCA01 [4.436 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOCA01
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TUOCA03	Commissioning of the European XFEL Injector	gun, emittance, laser, controls	1044
	F. Brinker DESY, Hamburg, Germany
	The European XFEL Injector consists of an L-Band RF photoinjector, a TESLA type 1.3 GHz module, a 3rd harmonic RF section, a laser heater and an extensive diagnostic section to determine projected and slice properties of the beam. The commissioning of the complete system has been started in December 2015 after several years of construction. We will report on commissioning results and persepctives for the later XFEL operation.
	Slides TUOCA03 [5.182 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOCA03
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TUZB01	High Power Proton Beam Targets: Technological Evolution, Current Challenges, and the Future	target, neutron, proton, radiation	1075
	J. Galambos 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 talk reviews the history of proton beam target development and the current challenges associated with the operation of high power beam targets. Beyond providing high power proton beams, accelerator facilities must also engineer robust targets to accept the load and satisfy mission needs. Recently some high power facilities are limited by target operations, rather than accelerator capabilities. The outlook for targets for future high power facilities is also considered.
	Slides TUZB01 [8.971 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUZB01
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TUPMB017	The Injection Septum Magnet for the Collector Ring (FAIR)	injection, septum, vacuum, lattice	1145
	P.Yu. Shatunov, D.E. Berkaev, I. Koop, E.P. Semenov, D.B. Shwartz BINP SB RAS, Novosibirsk, Russia A. Dolinskyy, S.A. Litvinov GSI, Darmstadt, Germany Yu. A. Rogovsky Budker INP & NSU, Novosibirsk, Russia
	Collector Ring is one of the key installations of the FAIR project (Darmstadt, Germany). It is dedicated for stochastic cooling of incoming beams of antiprotons and rare ions. Additionally there is a mode of operation for experiments in the ring. Beams for all modes of operation are injected through one transfer channel. Extremely high acceptance of the ring (240 mm*mrad) leads to large apertures of all magnetic elements including the septum magnet. Meanwhile planned parameters of the magnetic field and magnetic field quality are comparatively strict. The present state of the design of the pulsed injection septum for the CR is presented in this article together with the concept of the injection system.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB017
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TUPMB026	Magnet System for a Compact Microtron	microtron, permanent-magnet, vacuum, electron	1164
	S.A. Kahn, R.J. Abrams, M.A.C. Cummings, R.P. Johnson, G.M. Kazakevich Muons, Inc, Illinois, USA
	Funding: Funded by DOE SBIR grant DE-SC0013795 A compact microtron can be an effective gamma source that can be transported to locations outside the laboratory. As part of a Phase I project we have studied a portable microtron that can accelerate electrons with energies of 6 MeV and above as a source for gamma and neutron production. The mass of the magnet is a significant contribution to the overall mass of the system. This paper will discuss conceptual designs for both permanent magnet and electromagnet systems. The choice of mictrotron RF frequency range is determined by the application requirements. The RF frequency influences the size of the microtron magnet and consequently its weight. We have looked at how the design would vary with the different frequency configurations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB026
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TUPMB033	Design and Construction of the QC2 Superconducting Magnets in the SuperKEKB IR	solenoid, quadrupole, superconducting-magnet, focusing	1174
	N. Ohuchi, Y. Arimoto, N. Higashi, M. Iwasaki, M.K. Kawai, Y. Kondo, K. Tsuchiya, X. Wang, H. Yamaoka, Z.G. Zong KEK, Ibaraki, Japan H.K. Kono, T. Murai, S. Takagi Mitsubishi Electric Corp., Energy Systems Centre, Kobe, Japan
	SuperKEKB is now being constructed with a target luminosity of 8×10³⁵ which is 40 times higher than the KEKB luminosity. The luminosity can be achieved by the "Nano-Beam" accelerator scheme, in which both beams should be squeezed to about 50 nm at the beam interaction point, IP. The beam final focusing system consists of 8 superconducting quadrupole magnets, 4 superconducting solenoids and 43 superconducting corrector coils. The QC2 magnets are designed to be located in the second closest position from IP as the final beam focusing system of SuperKEKB. The two types of quadrupole magnets have been designed for the electron and positron beam lines. The QC2P for the positron beam is designed to generate the field gradient, G, of 28.1 T/m and the effective magnetic length, L, of 0.4099 m at the current, I, of 877.4 A. The QC2E for the electron beam line is designed to generate G=28.44 T/m and L=0.537 mm, 0.419 mm (for QC2LE, QC2RE) at I=977 A. In the paper, we will present the designs and the constructions of the two types of the quadrupole magnets.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB033
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TUPMB034	Design and Manufacture of a Superconducting Solenoid for D-Line of J-PARC Muon Facility	solenoid, vacuum, interface, radiation	1177
	T. Semba, Y. Hagiwara, S. Kido, S. Nakajima, Y. Tanaka Hitachi Ltd., Ibaraki-ken, Japan N. Kawamura, Y. Makida, Y. Miyake, H. Ohhata, K. Sasaki, K. Shimomura KEK, Ibaraki, Japan N. Kurosawa KEK, Tokai Branch, Tokai, Naka, Ibaraki, Japan Y. Murata Hitachi, Ltd., Energy and Environmental System Laboratory, Hitachi-shi, Japan P. Strasser High Energy Accelerator Research Organization (KEK), Institute of Materials Structure Science (IMSS), Ibaraki, Japan
	A superconducting solenoid for J-PARC muon facility was newly designed and manufactured. High Energy Accelerator Research Organization (KEK) has been operating the J-PARC Muon Science Establishment (MUSE) since 2008. Among its four muon beam lines, the decay muon line (D-Line) has been extracting and providing surface muons and positive decay muons up to a momentum of 50 MeV/c for various users, utilizing a superconducting solenoid. The D-Line as well as the other J-PARC facility suffered severe damages from the earthquake on March 11, 2011. It necessitated rebuilding of the damaged superconducting solenoid. New design parameter of the solenoid is as follows: length of solenoid: 6 m, diameter of warm bore: 0.2 m, magnetic field of bore center: 3.5 T, rated current: 415 A, superconducting wire: NbTi/Cu, quench protection: quench back heaters. The six-meter-long solenoid consists of twelve pieces of 0.5-meter-long superconducting coils. The entire solenoid is forced-indirectly cooled by supercritical helium flow. This report describes the design and manufacturing process of the newly built superconducting solenoid for D-Line of J-PARC muon facility.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB034
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TUPMB035	Developments of HTS Magnets towards Application to Accelerators	dipole, neutron, target, cyclotron	1180
	K. Hatanaka, M. Fukuda, K. Kamakura, H. Ueda, Y. Yasuda, T. Yorita RCNP, Osaka, Japan
	We have been developing magnets utilizing first generation HTS wire for this decade. HTS materials have advantages over LTS materials. Magnets can be operated at 20 K or higher temperature and the cooling structure becomes simpler. Owing to a large margin in operating temperature, it is possible to excite HTS magnets by AC or pulsed currents without quenching. After successful performance tests of proto type models, two magnets have been fabricated for practical use. A cylindrical magnet generates a magnetic field higher than 3.5 T at the center to polarized 210 neV neutrons. A dipole magnet is excited by pulse currents in order to deliver accelerated beams to two target stations by time sharing. Their design and operational performance are discussed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB035
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TUPMB038	Degradation of the Insulation of the LHC Main Dipole Cable when Exposed to High Temperatures	dipole, superconducting-magnet, laser, high-voltage	1186
	V. Raginel, B. Auchmann, D. Kleiven, R. Schmidt, A.P. Verweij, D. Wollmann CERN, Geneva, Switzerland
	Funding: Research supported by the High Luminosity LHC project The energy stored in the LHC beams is substantial and requires a complex machine protection system to protect the equipment. Despite efficient beam absorbers, several failure modes lead to some limited beam impact on superconducting magnets. Thus it is required to understand the damage mechanisms and limits of superconducting magnets due to instantaneous beam impact. This becomes even more important due to the future upgrade of CERNs injector chain for the LHC that will lead to an increase of the beam brightness. A roadmap to perform damage tests on magnet parts has been presented previously. The polyimide insulation of the superconducting cable is identified as one of the critical elements of the magnet. In this contribution, the experimental setup to measure the insulation degradation of LHC main dipole cables due to exposure to high temperature is described. Compressed stacks of insulated Nb-Ti cables have been exposed to a heat treatment within an Argon atmosphere. After each heat treatment, high-voltage measurements verified the dielectric strength of the insulation. The results of this experiment provide an upper damage limit of superconducting magnets due to beam impact. Experimental Setups to Determine the Damage Limit of Superconducting Magnets for Instantaneous Beam Losses, V. Raginel et al, IPAC'15
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TUPMB040	LHC Accelerator Fault Tracker - First Experience	cryogenics, hardware, ion, luminosity	1190
	A. Apollonio, L. Ponce, C. Roderick, R. Schmidt, B. Todd, D. Wollmann CERN, Geneva, Switzerland
	Availability is one of the key performance indicators of LHC operation, being directly correlated with integrated luminosity production. An effective tool for availability tracking is a necessity to ensure a coherent capture of fault information and relevant dependencies on operational modes and beam parameters. At the beginning of LHC Run 2 in 2015, the Accelerator Fault Tracking (AFT) tool was deployed at CERN to track faults or events affecting LHC operation. Information derived from the AFT is crucial for the identification of areas to improve LHC availability, and hence LHC physics production. For the 2015 run, the AFT has been used by members of the CERN Availability Working Group, LHC Machine coordinators and equipment owners to identify the main contributors to downtime and to understand the evolution of LHC availability throughout the year. In this paper the 2015 experience with the AFT for availability tracking is summarised and an overview of the first results as well as an outlook to future developments is given.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB040
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TUPMR019	Measurements of the Beam Phase Response to Correcting Magnetic Fields in PSI Cyclotrons	cyclotron, simulation, diagnostics, proton	1271
	A.S. Parfenova, C. Baumgarten, J.M. Humbel, A.C. Mezger PSI, Villigen PSI, Switzerland A.V. Petrenko CERN, Geneva, Switzerland
	The cyclotron-based proton accelerator facility (HIPA) at PSI is presently operated at 1.3-1.4 MW beam power at a kinetic energy of 590 MeV/u to drive the neutron spallation source SINQ and for production of pion and muon beams. Over the years HIPA facility has developed towards increase of the delivered beam current and beam power (0.1 mA in 1974 till 2.2 mA in 2010). During the last few years several upgrades of the Ring cyclotron field correction and beam phase monitoring systems were made. RF voltage was also increased. In order to test the performance of the upgraded system the phase response measurements were carried out.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR019
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TUPMR025	Design of the LBNF Beamline	target, proton, shielding, extraction	1291
	V. Papadimitriou, K. Ammigan, J.E. Anderson, K. Anderson, R. Andrews, V.T. Bocean, C.F. Crowley, N. Eddy, B.D. Hartsell, S. Hays, P. Hurh, J. Hylen, J.A. Johnstone, P.H. Kasper, T.R. Kobilarcik, G.E. Krafczyk, B.G. Lundberg, A. Marchionni, N.V. Mokhov, C.D. Moore, D. Pushka, I.L. Rakhno, S.D. Reitzner, P. Schlabach, V.I. Sidorov, A.M. Stefanik, S. Tariq, L.R. Valerio, K. Vaziri, G. Velev, G.L. Vogel, K.E. Williams, R.M. Zwaska Fermilab, Batavia, Illinois, USA C.J. Densham STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
	Funding: Work supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The Long Baseline Neutrino Facility (LBNF) will utilize a beamline located at Fermilab to provide and aim a neutrino beam of sufficient intensity and appropriate energy range toward DUNE detectors, placed deep underground at the SURF Facility in South Dakota. The primary proton beam (60 - 120 GeV) will be extracted from the MI-10 section of Fermilab's Main Injector. Neutrinos are produced after the protons hit a solid target and produce mesons which are subsequently focused by magnetic horns into a 194 m long decay pipe where they decay into muons and neutrinos. The parameters of the facility were determined taking into account the physics goals, spacial and radiological constraints and the experience gained by operating the NuMI facility at Fermilab. The Beamline facility is designed for initial operation at a proton-beam power of 1.2 MW, with the capability to support an upgrade to 2.4 MW. LBNF/DUNE obtained CD-1 approval in November 2015. We discuss here the design status and the associated challenges as well as the R&D and plans for improvements before baselining the facility.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR025
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TUPMR032	Initial Commissioning of the Rutherford Appleton Laboratory (RAL) Scaled Negative Penning Ion Source	interface, plasma, cathode, space-charge	1314
	D.C. Faircloth, S.R. Lawrie, T. Rutter, M. Whitehead, T. Wood STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	A new high duty factor, scaled Penning surface plasma source is being developed at RAL. This paper provides initial commissioning results. A stable high-current (up to 100 A) pulsed discharge is obtained, but the anode overheats, caused by poor thermal contact at elevated temperatures. The overheating anode yields a noisy discharge, with low output current, and makes high duty factor operation impossible. The performance of a thermal interface material for aperture plate (plasma electrode) cooling is detailed. An update on the cathode heaters is provided. The anode to source-body fit is analysed at different temperatures for different combinations of mechanical tolerances. This offers insights when compared to ISIS operational sources. A new anode with modified tolerance dimensions for improved fit is being manufactured and will be tested in June 2016.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR032
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TUPMR039	The Development of a New High Field Injection Septum Magnet System for Main Ring of J-Parc	injection, septum, power-supply, flattop	1337
	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. It is necessary to exchange a high field injection septum magnet which will be installed at the injection line from RCS to MR and its power supply, because the current injection septum system can not be operated with 1.3 second repetition. Since confirmed the large leakage field around current circling beam line of the injection magnet, we must improve the shielding structure which make low leakage field. We started the development of the new injection septum magnet and its power supply in 2013. It can operate with 1 Hz repetition and the low leakage field which its order is 10^-4 of the gap field. The new Injection septum magnet and the new power supply were constructed in Winter of 2014. We had many improvement of the magnet and power supply. We will install the new injection septum magnet system in this summer. In this presentation, we will report the detail of the results of its performance.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR039
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TUPMR040	The Development of a New Low Field Septum Magnet System for Fast Extraction in Main Ring of J-PARC	septum, power-supply, vacuum, extraction	1340
	T. Shibata, K. Ishii, H. Matsumoto, N. Matsumoto, T. Sugimoto KEK, Ibaraki, Japan K. Fan 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.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR040
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TUPMR049	Feasibility Study of the PS Injection for 2 GeV LIU Beams with an Upgraded KFA-45 Injection Kicker System Operating in Short Circuit Mode	simulation, injection, kicker, flattop	1363
	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
	Under the scope of the LIU project the CERN PS Booster to PS beam transfer will be modified to match the requirements for the future 2 GeV beams. This paper describes the evaluation of the proposed upgrade of the PS injection kicker. Different schemes of an injection for LIU beams into the PS have been outlined in the past already under the aspect of individual transfer kicker rise and fall time performances. Homogeneous rise and fall time requirements in the whole PSB to PS transfer chain have been established which allowed to consider an upgrade option of the present injection kicker system operated in short circuit mode. The challenging pulse quality constraints require an improvement of the flat top and post pulse ripples. Both operation modes, terminated and short circuit mode are analysed and analogue circuit simulations for the present and upgraded system are outlined. Recent measurements on the installed kickers are presented and analysed together with the simulation data. First measurements verifying the performance of upgrade options have been taken during the last end of the year stop. The paper concludes with an upgrade plan and a brief overview of implementation risks.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR049
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TUPMR053	Initial Experience with Carbon Stripping Foils at ISIS	injection, synchrotron, proton, vacuum	1378
	B. Jones, D.J. Adams, H. V. Smith STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS Facility at the Rutherford Appleton Laboratory is a spallation neutron and muon source based upon a 50 Hz rapid cycling synchrotron accelerating ~3×10¹³ protons per pulse from 70 to 800 MeV to deliver a mean beam power of 0.2 MW to two target stations. Throughout its 30 years of operation ISIS has developed aluminium oxide foils in-house for H− charge exchange injection. The manufacturing and installation processes for these foils are time consuming, radiologically dose intensive and require a high degree of skill. Commercially available carbon based foils commonly used at other facilities, have the potential to greatly simplify foil preparation and installation in addition to improving beam quality. Similar foils would also be necessary for facility upgrades which increase injection energy to withstand the higher operating temperatures. This paper describes the initial experience of carbon foils in the ISIS synchrotron including issues relating to handling and mounting foils, their performance under beam operation and plans for further development.
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TUPMR057	High Current Proton and Carbon Beam Operation via Stripping of a Molecular Beam at GSI UNILAC	proton, ion, linac, ion-source	1390
	M. Heilmann, A. Adonin, W.A. Barth, Ch.E. Düllmann, R. Hollinger, E. Jäger, P. Scharrer, W. Vinzenz, H. Vormann GSI, Darmstadt, Germany W.A. Barth, Ch.E. Düllmann, P. Scharrer HIM, Mainz, Germany Ch.E. Düllmann Johannes Gutenberg University Mainz, Institut of Nuclear Chemistry, Mainz, Germany P. Scharrer Mainz University, Mainz, Germany
	The experimental program of the future facility for Antiproton and Ion Research (FAIR) project requires a high number of cooled anti-protons per hour. The FAIR proton injector linac has to deliver a 70 MeV, 35 mA pulsed proton beam at a repetition rate of 4 Hz. During recent machine investigations at the GSI a high current proton beam was achieved in the Universal Lineral Accelerator (UNILAC). In preparation for this the ion source was equipped with a newly developed 7-hole extraction system and optimized for single charged hydrocarbon beam (isobutane gas) operation. This beam was accelerated to 1.4 MeV/u and cracked in a new pulsed gas stripper into protons and charged carbon. The new stripper setup injects high density gas pulses synchronous with the transit of the beam pulse close to the beam trajectory. With this setup a proton (up to 4.3 mA) as well a carbon beam (up to 9.5 mA) intensity record at beam energy of 1.4 MeV was achieved. The proton beam was accelerated up to 3.6 MeV/u inside the first Alvarez-section with full transmission. The paper will present beam measurement in comparison to the former beam investigations using a 2 mA proton beam in the entire UNILAC.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR057
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TUPMW012	Beam Offset Stabilization Techniques for the LHC Collision Points	luminosity, experiment, optics, ground-motion	1438
	A.A. Gorzawski, R. Jacobsson, J. Wenninger CERN, Geneva, Switzerland
	Maintaining head-on collisions over many hours is an important aspect of optimizing the performance of a collider. For current LHC operation where the beam optics is fixed during periods of colliding beam, mainly ground motion induced perturbations have to be compensated. The situation will become significantly more complex when luminosity leveling will be applied following the LHC luminosity upgrades. During β^* leveling the optics in the interaction region changes significantly, feed-downs from quadrupole misalignment may induce significant orbit changes that may lead to beam offsets at the collision points. Such beam offsets induce a loss of luminosity and reduce the stability margins for collective effects that is provided by head-on beam-beam. It is therefore essential that the beam offsets at the collision points are minimized during the leveling process. This paper will review sources and mitigation techniques for the orbit perturbation at the collision points during β^* leveling, and present results of experiments performed at the LHC to mitigate and compensate such offsets.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW012
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TUPMW014	Improved Aperture Measurements at the LHC and Results from their Application in 2015	alignment, injection, insertion, beam-losses	1446
	P.D. Hermes, R. Bruce, M. Fiascaris, H. Garcia, M. Giovannozzi, A. Mereghetti, D. Mirarchi, E. Quaranta, S. Redaelli, B. Salvachua, G. Valentino CERN, Geneva, Switzerland R. Kwee-Hinzmann Royal Holloway, University of London, Surrey, United Kingdom E. Quaranta Politecnico/Milano, Milano, Italy
	A good knowledge of the available aperture in the LHC is essential for a safe operation due to the risk of magnet quenches or even damage in case of uncontrolled beam losses. Experimental validations of the available aperture are therefore crucial and were in the past carried out by either a collimator scan combined with beam excitations or through the use of local orbit bumps. In this paper, we show a first comparison of these methods in the same machine configuration, as well as a new very fast method based on a beam-based collimator alignment and a new faster variant of the collimator scan method. The methods are applied to the LHC operational configuration for 2015 at injection and with squeezed beams and the measured apertures are presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW014
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TUPMW017	Electron Cloud Observations during LHC Operation with 25 ns Beams	electron, injection, simulation, cryogenics	1458
	K.S.B. Li, H. Bartosik, G. Iadarola, L. Mether, A. Romano, G. Rumolo, M. Schenk CERN, Geneva, Switzerland
	While during the Run 1 (2010-2012) of the Large Hadron Collider (LHC) most of the integrated luminosity was produced with 50 ns bunch spacing, for the Run 2 start-up (2015) it was decided to move to the nominal bunch spacing of 25 ns. As expected, with this beam configuration strong electron cloud effects were observed in the machine, which had to be mitigated with dedicated 'scrubbing' periods at injection energy. This enabled to start the operation with 25 ns beams at 6.5 TeV, but e-cloud effects continued to pose challenges while gradually increasing the number of circulating bunch trains. This contribution will review the encountered limitations and the mitigation measures that where put in place and will discuss possible strategies for further performance gain.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW017
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TUPMW023	Macroparticle-Induced Losses During 6.5 TeV LHC Operation	proton, electron, beam-losses, luminosity	1481
	G. Papotti, M. Albert, B. Auchmann, E.B. Holzer, M.K. Kalliokoski, A. Lechner CERN, Geneva, Switzerland
	One of the major performance limitations for operating the LHC at high energy was feared to be the so called UFOs (Unidentified Falling Objects, presumably micrometer sized dust particles which lead to fast beam losses when they interact with the beam). Indeed much higher rates were observed in 2015 compared to Run 1, and about 20 fills were prematurely terminated by too high losses caused by such events. Additionally they triggered a few beam induced quenches at high energy, the first in the history of the LHC. In this paper we review the latest update on the analysis of these events, e.g. the conditioning observed during the year and possible correlations with beam and machine parameters. At the same time we also review the optimization of beam loss monitor thresholds in terms of machine protection and availability.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW023
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TUPMW026	Feed-Forward Corrections for Tune and Chromaticity Injection Decay During 2015 LHC Operation	injection, hadron, collider, octupole	1489
	M. Solfaroli Camillocci, M. Juchno, M. Lamont, M. Schaumann, E. Todesco, J. Wenninger CERN, Geneva, Switzerland
	After two years of shutdown, the Large Hadron Collider (LHC) has been operated in 2015 at 6.5 TeV, close to its designed energy. When the current is stable at low field, the harmonic components of the main circuits are subject to a dynamic variation induced by current redistribution on the superconducting cables. The Field Description of the LHC (FiDel) foresaw an increase of the decay at injection of tune (quadrupolar components) and chromaticity (sextupolar components) of about 50% with respect to LHC Run1 due to the higher operational current. This paper discusses the beam-based measurements of the decay during the injection plateau and the implementation and accuracy of the feed-forward corrections as present in 2015. Moreover, the observed tune shift proportional to the circulating beam intensity and it's foreseen feed-forward correction are covered.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW026
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TUPMW027	The 2015 Heavy-Ion Run of the LHC	luminosity, ion, experiment, heavy-ion	1493
	J.M. Jowett, R. Alemany-Fernandez, R. Bruce, M. Giovannozzi, P.D. Hermes, W. Höfle, M. Lamont, T. Mertens, S. Redaelli, M. Schaumann, J.A. Uythoven, J. Wenninger CERN, Geneva, Switzerland
	In late 2015 the LHC collided lead nuclei at a beam energy of 6.37 Z TeV, chosen to match the 5.02 TeV per colliding nucleon pair of the p-Pb collision run in 2013. In so doing, it surpassed its design luminosity by a factor of 2. Besides the higher energy, the operational configuration had a number of new features with respect to the previous Pb-Pb run at 3.5 Z TeV in 2011; unusual bunch patterns providing collisions in the LHCb experiment for the first time, luminosity levelling and sharing requirements, a vertical displacement of the interaction point in the ALICE experiment, and operation closer to magnet quench limits with mitigation measures. We present a summary of the commissioning and operation and what has been learned in view of future heavy-ion operation at higher luminosity.
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TUPMW030	Review of LHC On-line Model Implementation and of its Applications	optics, quadrupole, database, interface	1505
	T. Persson, J.M. Coello de Portugal, M. Fjellstrom, L. Malina, J. Roy, P.K. Skowroński, A. Szczotka CERN, Geneva, Switzerland J.S. Moeskops RID, Delft, The Netherlands
	The online model of the LHC aims to provide an accurate description of the machine at any given time. In order to do so it extracts the current optics in the machine along with other crucial parameters. It also provides the functionality to match the measured orbit using virtual correctors and the measured beta functions using virtual quadrupoles. In this way an accurate effective model can be created. In order to facilitate the use of the online model a graphical user interface has been developed. In this article we describe the design of the online model and its application in different studies. We give examples how it has been used to predict the influence of changes before they were applied to the machine.
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TUPMW031	Combined Ramp and Squeeze to 6.5 TeV in the LHC	optics, controls, dipole, betatron	1509
	M. Solfaroli Camillocci, S. Redaelli, R. Tomás, J. Wenninger CERN, Geneva, Switzerland
	The cycle of the LHC is composed of an energy ramp followed by a betatron squeeze, needed to reduce the beta- star value in the interaction points. Since Run 1, studies have been carried out to investigate the feasibility of combining the two operations, thus considerably reducing the duration of the operational cycle. In Run 2, the LHC is operating at the energy of 6.5 TeV that requires a much longer cycle than that of Run 1. Therefore, the performance gains from a Combined Ramp and Squeeze (CRS) is more interesting. Merging the energy ramp and the betatron squeeze could result in a gain of several minutes for each LHC cycle. With increasing maturity of LHC operation, it is now possible to envisage more complex beam manipulations; this paper describes the first machine experiment with beam, aiming at validating the combination of ramp and squeeze, which was performed in 2015, during a machine development phase. The operation experience with the LHC run at 2.51 TeV, when CRS down to 4 meters was deployed and a the first results of 2016 run are also reviewed.
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TUPMW038	RHIC Operation with Asymmetric Collisions in 2015	proton, injection, emittance, cavity	1527
	C. Liu, E.C. Aschenauer, G. Atoian, M. Blaskiewicz, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, W. Fischer, C.J. Gardner, X. Gu, T. Hayes, H. Huang, R.L. Hulsart, J.S. Laster, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, G. Narayan, S.K. Nayak, S. Nemesure, P.H. Pile, A. Poblaguev, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, W.B. Schmidke, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, G. Wang, K. Yip, A. Zaltsman, K. Zeno, S.Y. Zhang BNL, Upton, Long Island, New York, USA S.M. White ESRF, Grenoble, France
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Collisions with beams of highly asymmetric rigidities (proton-Gold and proton-Aluminum) were provided for the RHIC physics programs in 2015. Magnets were moved for the first time in RHIC prior to the run to accommodate the asymmetric beam trajectories during acceleration and at store. A special ramping scheme was designed to keep the revolution frequencies of the beams in the two rings equal. The unique operational experience of the asymmetric run will be reviewed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW038
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TUPMY005	A Muon Source Proton Driver at JPARC-based Parameters	proton, injection, booster, linac	1550
	D.V. Neuffer Fermilab, Batavia, Illinois, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the U. S. Department of Energy. An "ultimate" high intensity proton source for neutrino factories and/or muon colliders was projected to be a ~4 MW multi-GeV proton source providing short, intense proton pulses at ~15 Hz. The JPARC ~1 MW accelerators provide beam at parameters that in many respects overlap these goals. Proton pulses from the JPARC Main Ring can readily meet the pulsed intensity goals. We explore these parameters, describing the overlap and consider extensions that may take a JPARC-like facility toward this "ultimate" source. JPARC itself could serve as a stage 1 source for such a facility.
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TUPOR008	Effect of the Various Impedances on Longitudinal Beam Stability in the CERN SPS	impedance, HOM, simulation, vacuum	1666
	A. Lasheen, T. Argyropoulos, J. Repond, E.N. Shaposhnikova CERN, Geneva, Switzerland
	The High Luminosity (HL)-LHC project at CERN aims at a luminosity increase by a factor ten and one of the necessary ingredients is doubling the bunch intensity to 2.4x10¹¹ ppb for beams with 25 ns bunch spacing. Many improvements are already foreseen in the frame of the LHC Injector Upgrade (LIU) project, but probably this intensity would still not be reachable in the SPS due to longitudinal instabilities. Recently a lot of effort went into finding the impedance sources of the instabilities. Particle simulations based on the latest SPS impedance model are now able to reproduce the measured instability thresholds and were used to determine the most critical impedance sources by removing them one by one from the model. It was found that impedance of vacuum flanges and of the already damped 630 MHz HOM of the main RF system gave for 72 bunches the comparable intensity thresholds. Possible intensity gains are defined for realistic impedance modifications and for various beam configurations (number of bunches, longitudinal emittances) and RF programs (single and double RF). The results of this study are used as a guideline for planning of a new campaign of the SPS impedance reduction.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR008
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TUPOR016	A Multi-GeV Recirculating Proton Linac	proton, linac, cavity, acceleration	1688
	J. Qiang LBNL, Berkeley, California, USA
	A high power GeV proton linac has many scientific applications. Recirculating RF linac as an efficient accelerator has been used and proposed to accelerate both electron and muon beams. In this paper, we propose using a multi-pass recirculating RF linac to attain a multi-GeV high power proton beam. This linac consists of three types of superconducting RF cavities that accelerate the proton beam multiple times from 150 MeV to final multiple GeV energy. Such a recirculating linac can significantly reduce the number of RF cavities in the accelerator and lower the cost of the facility.
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TUPOR026	Final Design and Status of the Third Recirculation for the S-DALINAC*	recirculation, dipole, linac, electron	1717
	M. Arnold, T. Kürzeder, N. Pietralla TU Darmstadt, Darmstadt, Germany F. Hug IKP, Mainz, Germany
	Funding: *Work supported by DFG through CRC 634 and RTG 2128 Since 1991 the twice-recirculating superconducting accelerator S-DALINAC is providing electron beams for nuclear physics experiments. Due to a reduced quality factor of its cavities in comparison to their design values it was not possible to operate the accelerator with its maximum design energy of 130 MeV in cw mode. To provide electron beams of this energy in the future it was decided to add one recirculation beam line in order to use the main linac four times, operating the cavities on decreased accelerating gradients. The necessary modifications consist of several different aspects: A new beamline needs to be installed and other pre-existing beam line sections have to be modified for matching new boundary conditions. These new conditions are mainly a result of beam dynamics simulations and of the design of a new separation dipole magnet, which will bend the different beams energy-dependent in the various recirculation beam lines. We will present the implemented design and give a status report on the project.
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TUPOW003	High Average RF Power Tests With 2 RF Vacuum Windows at PITZ	gun, vacuum, Windows, emittance	1744
	Y. Renier, G. Asova, M. A. Bakr, P. Boonpornprasert, J.D. Good, M. Groß, C. Hernandez-Garcia, H. Huck, I.I. Isaev, D.K. Kalantaryan, M. Krasilnikov, O. Lishilin, G. Loisch, D. Malyutin, D. Melkumyan, A. Oppelt, M. Otevřel, G. Pathak, T. Rublack, I.V. Rybakov, F. Stephan, G. Vashchenko, Q.T. Zhao DESY Zeuthen, Zeuthen, Germany M. Bousonville, S. Choroba, S. Lederer DESY, Hamburg, Germany
	The Photo Injector Test facility at DESY, Zeuthen site (PITZ), was built with the aim to develop and characterize electron sources for future usage at FLASH and at the European XFEL. Recently, the main focus at PITZ has been the study of gun reliability and photoinjector performance at high average power. The goal is to get stable and reliable operation with 6.4 MW peak power in the gun at 650 us RF pulse length and 10 Hz repetition rate. To achieve this, a new RF feed system with two RF windows was installed at PITZ in 2014. During this test, the old gun 4.2 with a modified back-plane design for better cathode contact has been used. In this contribution the results of the RF conditioning of gun 4.2 with a detailed interlock analysis will be reported as well as results from recent electron beam characterization.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW003
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TUPOW005	Update on Third Harmonic XFEL Activities at INFN LASA	cavity, HOM, pick-up, diagnostics	1751
	D. Sertore, M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, P. Michelato, L. Monaco, R. Paparella, P. Pierini INFN/LASA, Segrate (MI), Italy C.G. Maiano DESY, Hamburg, Germany C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	After the successful installation and beam operation of the first batch of 3.9 GHz cavities into the XFEL Third Harmonic Injector Module, ten more cavities have been tested and delivered to DESY to be assembled into a spare cryomodule. In this paper, we report on the activities related to the cavities fabrication, treatment and vertical testing at INFN LASA.
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TUPOW036	Recent Developments and Operational Status of the Compact ERL at KEK	linac, emittance, laser, gun	1835
	T. Obina, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondo, T. Konomi, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, S. Sasaki, K. Satoh, Y. Seimiya, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, N. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida KEK, Ibaraki, Japan R. Hajima, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma QST, Tokai, Japan M. Kuriki Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
	The Compact Energy Recovery Linac (cERL) at KEK is a test accelerator in order to develop key components to realize remarkable ERL performance as a future light source. After the beam commissioning in December 2013, the legal current limit has been increased step-by-step like 1 uA, 10 uA, and 100 uA. Survey for the source of beam losses has been conducted in each step, and the study on beam dynamics and tuning has also been carried out. As a next step, 1 mA operation is scheduled in February 2016. In parallel to the increase in beam current, a laser Compton scattering (LCS) system which can provide high-flux X-ray to a beamline has been successfully commissioned. We report recent progress in various kinds of beam tuning: improvement of electron gun performance, high bunch charge operation, mitigation of beam losses, LCS optics tuning and bunch compression for THz radiation.
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TUPOW038	Measurement and Control of Beam Losses Under High Average-current Operation of the Compact ERL at KEK	radiation, beam-losses, recirculation, optics	1839
	S. Sakanaka, K. Haga, Y. Honda, H. Matsumura, T. Miyajima, T. Nogami, T. Obina, H. Sagehashi, M. Shimada, M. Yamamoto KEK, Ibaraki, Japan
	The compact ERL (cERL)* is a superconducting accelerator aimed at demonstrating excellent ERL technologies for the future light source. The cERL comprises a 5 MeV injector, a main linac, and a recirculation loop. In the cERL, production and transportation of low-emittance and high average-current beams (tentative goals: 1 mm-mrad and 10 mA) is primarily important. At this moment (in December 2015), beam currents of up to 80 uA (CW) have successfully been transported through the recirculation loop at a beam energy of 20 MeV. Before such high-current operations, we carefully tuned up the machine so that beam losses became very small. The beam losses were watched using fast beam-loss detectors and radiation monitors while absolute losses were estimated from measured radiation levels on the roof of the shield. After careful beam-optics corrections and elimination of beam halos / tails at low-energy section, we achieved the beam losses of at most a few nA level at several locations along the loop, and those below 1 nA elsewhere in the loop. We will report these results together with the result of higher-current operation which is planned early in 2016. * S. Sakanaka et al., IPAC'15, TUBC1; T. Obina et al., to be presented at IPAC'16.
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TUPOW039	Simulation Study of the Beam Halo Formation for Beam Loss Estimation and Mitigation at KEK Compact ERL	simulation, cavity, electron, gun	1843
	O. Tanaka, T. Miyajima, N. Nakamura, T. Obina, M. Shimada, R. Takai KEK, Ibaraki, Japan
	Funding: Work supported by the "Grant-in-Aid for Creative Scientific Research" of JSPS (KAKENHI 15K04747) At KEK Compact ERL (cERL) we are aiming to produce high-current and low-emittance electron beams (up to 10 mA) without significant beam loss. We believe that beam halo makes a significant impact into the beam loss. Therefore, we are performing beam loss simulations to meet the results of the beam loss measurements. In particular, a simulation of the bunch tail originated from the electron gun was performed to understand the mechanisms of the beam halo formation. Since some measured beam profiles demonstrated unexpected halo particles, several factors such as misalignment of beam line elements and kicks from the steering coils were added into the simulation. Simulation study results are compared with the related beam loss and halo measurements here. Sakanaka et al., these proceedings
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TUPOW043	Electron Beam Dynamics Studies for ELI-NP GBS Linac	electron, linac, beam-loading, photon	1857
	A. Giribono, F. Cardelli, L. Palumbo, L. Piersanti University of Rome La Sapienza, Rome, Italy D. Alesini, A. Gallo, C. Vaccarezza, A. Vannozzi INFN/LNF, Frascati (Roma), Italy A. Bacci, C. Curatolo, I. Drebot, V. Petrillo, A.R. Rossi, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy G. Campogiani Rome University La Sapienza, Roma, Italy F. Cardelli, L. Piersanti INFN-Roma1, Rome, Italy L. Palumbo INFN-Roma, Roma, Italy
	The ELI-NP Gamma Beam System is an advanced gamma ray source based on the Compton back-scattering effect with unprecedented specifications of brilliance ( >10²¹), monochromaticity (0.5%) and energy tunability (0.2 - 19.5 MeV), presently under construction in Magurele-Bucharest (RO). Here the head-on collision is foreseen between an intense high power laser beam and a high brightness high quality electron beam with a maximum kinetic energy of 740 MeV. The electron beam dynamics analysis and control for the ELI-NP GBS Linac in the single and multi bunch mode have been investigated and are here illustrated.
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Paper

Title

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MOOCA01

R&D of a Super-compact SLED System at SLAC

cavity, coupling, impedance, FEL

39

J.W. Wang, G.B. Bowden, S. Condamoor, Y. Ding, V.A. Dolgashev, J.P. Eichner, M.A. Franzi, A.A. Haase, P. Krejcik, J.R. Lewandowski, S.G. Tantawi, L. Xiao, C. Xu
SLAC, Menlo Park, California, USA

Funding: Work supported by Department of Energy contract DE-AC03-76SF00515.
We have successfully designed, fabricated, installed and tested a super-compact X-Band SLED system at SLAC. It is composed of an elegant mode converter/polarizer and a single sphere energy store cavity with high Q of 94000 and diameter less than 12 cm. The available RF peak power of 50 MW can be compressed to peak average power of more than 200 MW in order to double the kick for the electron bunches in a RF transverse deflector system and greatly improve the measurement resolution for both the electron bunch and the x-ray FEL pulse. High power operation has demonstrated the excellent performance of this RF compression system without any problems in RF breakdown, pulse heating and radiation. The design physics and fabrication as well as the measurement results will be presented in detail.

Slides MOOCA01 [20.278 MB]

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MOOCA03

Thyratron Replacement

klystron, network, linear-collider, electron

45

I. Roth, M.P.J. Gaudreau, M.K. Kempkes
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Funding: Work supported by DOE under contract DE-SC0011292
Semiconductor thyristors have long been used as a replacement for thyratrons in low power or long pulse RF systems. To date, however, such thyristor assemblies have not demonstrated the reliability needed for installation in short pulse, high peak power RF stations used with many pulsed electron accelerators. The fast rising current in a thyristor tends to be carried in a small region, rather than across the whole device, and this localized current concentration can cause a short circuit failure. An alternate solid-state device, the insulated-gate bipolar transistor (IGBT), can readily operate at the speed needed for the accelerator, but commercial IGBTs cannot handle the voltage and current required. It is, however, possible to assemble these devices in arrays to reach the required performance levels without sacrificing their inherent speed. Diversified Technologies, Inc. (DTI) has patented and refined the technology required to build these arrays of series-parallel connected switches. DTI is currently developing an affordable, reliable, form-fit-function replacement for the klystron modulator thyratrons at SLAC capable of pulsing at 360 kV, 420 A, 6 μs, and 120 Hz.

Slides MOOCA03 [2.636 MB]

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MOZB02

Challenges of the High Current Prototype Accelerator of IFMIF/EVEDA

rfq, linac, neutron, ion

52

J. Knaster, Y. Okumura
IFMIF/EVEDA, Rokkasho, Japan
P. Cara
Fusion for Energy, Garching, Germany
A. Kasughai
Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan
M. Sugimoto
QST/Takasaki, Takasaki, Japan

LIPAc, under installation in Rokkasho will produce a 125 mA CW deuteron beam at 9 MeV. The objective of IFMIF is to generate a neutron flux of 10¹⁸ m-2s⁻¹ at 14 MeV for fusion materials testing using 2 x 125 mA CW D⁺ beams at 40 MeV impacting on a liquid lithium jet of 15 m/s. An ECR deuteron injector at 140 mA and 100 keV will be the source for a 9.7m long 4-vane RFQ, which will be complemented by a 175 MHz SRF linac composed of 8 HWRs for producing 9 MeV D⁺ beam. For a beam transmission >90%, beam simulations demand a D⁺ beam emittance below <0.3π mm·mrad. The first attempt on such high current accelerator was in the US in the early 80s under FMIT project with a H²⁺ 100 mA CW 2 MeV beam. LEDA successfully conducted 100 mA CW H⁺ at 6.7 MeV at the RFQ output energy in the late 90s, but using superconducting HWRs accelerating cavities at 125 mA CW with low-β H⁺/D⁺ beam has never been attempted. Beam halo will be monitored with 3 cryogenic μ-loss monitors azimuthally placed in each of the 8 superconducting solenoids interleaved with the HWR structures. A novel approach based on a beam core-halo dual matching has been developed to handle the MW range beam average power.

Slides MOZB02 [18.358 MB]

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MOPMB002

First Measurements of Coherent Smith-Purcell Radiation in the SOLEIL Linac

detector, linac, radiation, experiment

69

N. Delerue, J. Barros, S. Jenzer, V. Khodnevych, M.S. Malovytsia
LAL, Orsay, France
N. Hubert, M. Labat
SOLEIL, Gif-sur-Yvette, France
V. Khodnevych
National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine
M.S. Malovytsia
KhNU, Kharkov, Ukraine

Funding: The authors are grateful for the funding received from the French ANR (contract ANR-12-JS05-0003-01).
An experiment to measure the Coherent Smith-Purcell radiation has been installed in the SOLEIL Linac. Its aim is to produce a map of Smith-Purcell radiation emissions in several planes and compare it with theoretical predictions. Coherent Smith Purcell radiation is produced when a grating is brought close from a sufficiently short charged particles beam. The experiment consist of two detectors with 5 degrees of freedom. These two detectors can be moved around the emission point to measure the intensity of the radiation at different locations. Radiation maps are recorded parasitically by moving the detectors around during normal linac operations.

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MOPMB009

Electron Beam Probe for the Bunch Length Measurements at BERLinPro

electron, diagnostics, simulation, gun

92

D. Malyutin, A.N. Matveenko
HZB, Berlin, Germany

For the successful operation of various accelerator facilities a detailed bunch characterization is required. A complete description can be achieved using various diagnostic systems installed along an accelerator beamline. Ideally the diagnostic should be able to measure parameters of a single bunch in a non-destructive manner. For bunch length measurements this results in a complicated task especially for bunch duration below 1 ps. One of the possible solutions is a diagnostic based on the interaction of a low energy electron beam with electro-magnetic fields of the relativistic bunch. The bunch length can be readily deduced from the resulting scatter. In this paper bunch length measurement technique based on a low energy electron beam is introduced. Results of numerical simulations of measurements are presented. A possible setup of such diagnostic system for BERLinPro facility is proposed.

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MOPMB043

Preliminary Research of HLS II BLM System

storage-ring, vacuum, detector, site

190

F.F. Wu, X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, J.G. Wang, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China
Y.K. Chen
IHEP, Beijing, People's Republic of China

Beam loss monitor system has been designed in many electron storages in order to indirectly measure lost electrons, which can be used to analysis beam loss mechanism and beam life. It can contribute to beam commissioning and improving stable operation of storage ring. According to lattice structure of the HLS II storage ring, 64 beam loss detectors have been located in the upper, lower, inner, outer side surfaces of vacuum chamber in the HLS II storage ring. Some preliminary researches based on the HLS II BLM system have been done. The results in successfully stable operation and unsuccessfully stable operation in beam commissioning stage were compared. Analysis of a sudden lost beam phenomenon were carried out.

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MOPMB057

Automatic Microbeam Focusing for X-Ray Microbeam Experiments at the 4B Beamline of Pohang Light Source-II

focusing, controls, experiment, LabView

220

K.H. Gil, H. J. Choi, J.-H. Lim
PAL, Pohang, Republic of Korea

The 4B beamline of the Pohang Light Source-II performs X-ray microdiffraction and microfluorescence experiments using X-ray microbeams. When performing X-ray micro-experiments, an X-ray microbeam should first be prepared. Up to recently, the microbeams with vertical and horizontal sizes (full width at half maximum) of less than 3 μm have been achieved, by manually adjusting the translations and pitch angles of the vertically and horizontally focusing mirrors, in a Kirkpatrick'Baez (K-B) mirror system. In this research, we developed a program that automates the complex and cumbersome process of microbeam focusing, divided into half-cutting and focusing phases. The developed program was applied to the 4B beamline and enabled the focusing of an X-ray beam to a minimum size within one hour. This paper introduces the algorithms of the program and also examines its performance.

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MOPMR002

Bunch by Bunch Position Measurement and Analysis at PLS-II

injection, kicker, betatron, pick-up

232

J. Lee, M.-H. Chun, I. Hwang, D.T. Kim, G. Kim, T.-Y. Lee, D.C. Shin, S. Shin
PAL, Pohang, Republic of Korea

Beam dynamic phenomena described by bunch-by-bunch motion are important issues for a storage ring and are described by various theoretical formalisms. Direct measurements of the beam position related to different dynamical mechanisms are a useful information to accelerator optimization. In PLS-II, 20 GHz sampling oscilloscope synchronized with injection event (or triggered by beam loss signal) is used to measure direct bunch by bunch motion. Based on the measured data, the principal component analysis had been performed to get the insight into beam dynamic phenomena such as couple bunch instability and beam oscillation due to kicker leakage. In this paper, we will describe the measurement method and the result of analysis for coupled bunch instability.

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MOPMR013

Development, Calibration and Application of New-generation Dissectors with Picosecond Temporal Resolution

electron, laser, radiation, positron

251

O.I. Meshkov, O. Anchugov, V.L. Dorohov, G.Y. Kurkin, A.V. Petrozhitskii, D.A. Shvedov, E.I. Zinin
BINP SB RAS, Novosibirsk, Russia
P.B. Gornostaev, M.Ya. Schelev, E.V. Shashkov, A. V. Smirnov, A.I. Zarovskii
GPI, Moscow, Russia

Funding: The presented experimental results were implemented due to financial support of the Russian Science Foundation (Projects N 14-29-00295)
A dissector is an electron-optical device designed for measurement of periodic light pulses of subnanosecond and picosecond duration. LI-602 dissector developed at BINP is widely used for routine measurements of a longitudinal profile of electron and positron beams at BINP electron-positron colliders and other similar installations]. This dissector is a part of many optical diagnostic systems and provides temporal resolution of about 20 ps. Recently* a new generation of picosecond dissectors were created on the basis of the PIF-01/S1 picosecond streak-image tube designed and manufactured at the General Physics Institute Photoelectronics Department (Moscow). The device has demonstrated a temporal resolution of 3-4 ps (FWHM). The procedure of temporal resolution calibration and results of application of the new-generation picosecond dissector are given in this work.
*E.I. Zinin, O.I. Meshkov. JINST, 2015 1748-0221 10 P10024 doi:10.1088/1748-0221/10/10/P10024

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MOPMR019

Beam Tests of a Prototype Stripline Beam Position Monitoring System for the Drive Beam of the CLIC Two-beam Module at CTF3

electronics, pick-up, impedance, vacuum

270

A. Benot-Morell, A. Faus-Golfe
IFIC, Valencia, Spain
A. Benot-Morell, M. Wendt
CERN, Geneva, Switzerland
A. Faus-Golfe
LAL, Orsay, France
J.M. Nappa, S. Vilalte
IN2P3-LAPP, Annecy-le-Vieux, France

Funding: MINECO contract no. FPA2013-47883-C2-1-P. CLIC Collaboration Agreement, contract no. KE2638/BE. FNRA contract no. ANR-11-IDEX-0003-02.
In collaboration with LAPP and IFIC, two units of a prototype stripline Beam Position Monitor (BPM) for the CLIC Drive Beam (DB), and its associated readout electronics have been successfully installed and tested in the Two-Beam-Module (TBM) at the CLIC Test Facility 3 (CTF3) at CERN. This paper gives a short overview of the BPM system and presents the performance measured under different Drive Beam configurations.

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MOPMR025

Beam Size Estimation from Luminosity Scans at the LHC During 2015 Proton Physics Operation

luminosity, emittance, proton, experiment

290

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

As a complementary method for measuring the beam size for high-intensity beams at 6.5 TeV flat-top energy, beam separation scans were done regularly at the CERN Large Hadron Collider (LHC) during 2015 proton physics operation. The luminosities measured by the CMS experiment during the scans were used to derive the convoluted beam size and orbit offset bunch-by-bunch. This contribution will elaborate on the method used to derive plane-by-plane, bunch-by-bunch emittances from the scan data, including uncertainties and corrections. The measurements are then compared to beam size estimations from absolute luminosity, synchrotron light telescopes, and wire scanners. In particular, the evolution of the emittance over the course of several hours in collisions is studied and bunch-by-bunch differences are highlighted.

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MOPMR057

Measurements using Button BPM SUM Signal

electronics, storage-ring, beam-losses, insertion

377

W.X. Cheng, K. Ha, J. Mead, O. Singh, G.M. Wang
BNL, Upton, Long Island, New York, USA

Modern digital BPM detectors measure not only the beam positions, four buttons SUM signal can be very helpful for machine developments and operations. At NSLS-II, BPM SUM signal has been used from commissioning stage, to investigate localized beam losses. During top-off operation, precise beam lifetime measurement within relative short period of time becomes important. With many BPMs along the ring, BPM SUM can be a much more accurate tool to measure the beam current and lifetime. BPM SUM signal shall be proportional to beam current, and it may depends on button sizes and BPM chamber geometry, cable attenuations, electronics attenuations, beam position, bunch lengths, fill pattern etc. Experience of BPM SUM signals measurements will be presented.

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MOPMW003

Thermal Simulation of an Energy Feedback Normal Conducting RF Cavity

cavity, coupling, simulation, electron

396

M. Fakhari, K. Flöttmann, S. Pfeiffer, H. Schlarb
DESY, Hamburg, Germany
J. Roßbach
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
A. Yahaghi
CFEL, Hamburg, Germany

Thermal simulation has been performed for an energy feedback normal conducting RF cavity. The cavity is going to be used as a fast actuator to regulate the arrival time of the electron bunches in fs level in FLASH. By measuring the arrival time jitter of one bunch in a bunch train, the designed cavity apply a correcting accelerating or decelerating voltage to the next bunches. The input power of the cavity is provided by a solid state amplifier and will be coupled to the cavity via a loop on the body. To achieve the fs level precision of the arrival time, the cavity should be able to provide accurate accelerating voltage with a precision of 300 eV. We performed thermal simulation to find out the temperature distribution of the cavity and make sure that heating will not affect its voltage precision. The simulation results show that by using two input loops the coupling constant will vary from 4.11 to 4.13 during the operation of the cavity which effect on the bunchs' arrival time would be less than 0.25 fs. While using just one input loop can lead to an error of about 1 fs.

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MOPMW011

The Second Harmonic RF System for J-PARC MR Upgrade

cavity, impedance, injection, proton

420

C. Ohmori, K. Hara, K. Hasegawa, M. Toda, M. Yoshii
KEK, Tokai, Ibaraki, Japan
M. Nomura, T. Shimada, F. Tamura, M. Yamamoto
JAEA/J-PARC, Tokai-mura, Japan

Power upgrade scenario of J-PARC Main Ring includes replacement of RF cavities with higher field gradient using magnetic alloy cores, FT3L than the present ones. It also need to install the second harmonic RF cavity in the other section where dedicated water system for RF cavities is not available. Installation scenario of the second harmonic RF will be presented.

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MOPMW025

Vacuum RF Breakdown of Accelerating Cavities in Multi-Tesla Magnetic Fields

cavity, vacuum, Windows, electron

444

D.L. Bowring, A. Moretti, M.A. Palmer, D.W. Peterson, A.V. Tollestrup, K. Yonehara
Fermilab, Batavia, Illinois, USA
B.T. Freemire
IIT, Chicago, Illinois, USA
A.V. Kochemirovskiy
University of Chicago, Chicago, Illinois, USA
P.G. Lane, Y. Torun
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359.
Ionization cooling of intense muon beams requires the operation of high-gradient, normal-conducting RF structures within multi-Tesla magnetic fields. The application of strong magnetic fields has been shown to lead to an increase in vacuum RF breakdown. This phenomenon imposes operational (i.e. gradient) limitations on cavities in ionization cooling channels, and has a bearing on the design and operation of other RF structures as well, such as photocathodes and klystrons. We present recent results from Fermilab's MuCool Test Area (MTA), in which 201 and 805 MHz cavities were operated at high power both with and without the presence of multi-Tesla magnetic fields. We present an analysis of damage due to breakdown in these cavities, as well as measurements related to dark current and their relation to a conceptual model describing breakdown phenomena.

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MOPMW026

Resonant Control for Fermilab's PXIE RFQ

rfq, controls, resonance, cavity

447

D.L. Bowring, B.E. Chase, J. Czajkowski, J.P. Edelen, D.J. Nicklaus, J. Steimel, T.J. Zuchnik
Fermilab, Batavia, Illinois, USA
S. Biedron, A.L. Edelen, S.V. Milton
CSU, Fort Collins, Colorado, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359.
The RFQ for Fermilab's PXIE test program is designed to accelerate a < 10 mA H⁻ CW beam to 2.1 MeV. The RFQ has a four-vane design, with four modules brazed together for a total of 4.45 m in length. The RF power required is < 130 kW at 162.5 MHz. A 3 kHz limit on the maximum allowable frequency error is imposed by the RF amplifiers. This frequency constraint must be managed entirely through differential cooling of the RFQ's vanes and outer body and associated material expansion. Simulations indicate that the body and vane coolant temperature should be controlled to within 0.1 degrees C. We present the design of the cooling network and the resonant control algorithm for this structure, as well as results from initial operation.

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MOPMW028

Progress on the MICE RF Module at LBNL

cavity, vacuum, coupling, experiment

454

T.H. Luo, A.J. DeMello, A.R. Lambert, D. Li, T.J. Loew, S. Prestemon, S.P. Virostek, J.G. Wallig
LBNL, Berkeley, California, USA
T.G. Anderson, A.D. Bross, M.A. Palmer
Fermilab, Batavia, Illinois, USA
Y. Torun
IIT, Chicago, Illinois, USA

The international Muon Ionization Cooling Experiment aims to demonstrate the transverse cooling of a muon beam by ionization in energy absorbers. The final MICE cooling channel configuration has two RF modules, each housing a 201 MHz RF cavity used to compensate the longitudinal energy loss in the absorbers. The assembly of MICE RF Module is being carried out at LBL. In this paper we will report the recent progress on the assembly work.

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MOPMW032

Study of RF Breakdown in 805MHz Pillbox Modular Cavity in Strong Magnetic Field

cavity, radiation, site, pick-up

466

A.V. Kochemirovskiy
University of Chicago, Chicago, Illinois, USA
D.L. Bowring, A. Moretti, K. Yonehara
Fermilab, Batavia, Illinois, USA
B.T. Freemire
IIT, Chicago, Illinois, USA
Y. Torun
Illinois Institute of Technology, Chicago, Illlinois, USA

RF breakdown has a negative impact on a cavity's performance, especially with the presence of strong magnetic fields. This issue can arise in designs of muon ionization cooling channel, RF guns, klystrons and in many other applications. The MuCool Test Area at Fermilab is the facility that allows us to study the effects of static magnetic field on RF cavity operation. As a part of this research program, we have tested an 805MHz pillbox "modular" cavity in strong external magnetic fields. The design of the cavity allowed for a better control over sources of systematic error. "Modular" structure of the cavity enables easy dismounting of the endplates to perform inspection of inner surfaces after each run as well as swapping endplates to study the effects of various materials on breakdown phenomenon. Coupler design ensures maximum electric field enhancement on cavity axis, thus reducing breakdown probability in the coupler region. The results and analysis from high-power runs with zero and non-zero external magnetic fields will be presented.

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MOPMW034

Final Commissioning of the MICE RF Module Prototype with Production Couplers

cavity, vacuum, coupling, Windows

474

Y. Torun, P.G. Lane
Illinois Institute of Technology, Chicago, Illlinois, USA
T.G. Anderson, M. Backfish, D.L. Bowring, A. Moretti, D.V. Neuffer, D.W. Peterson, M. Popovic, K. Yonehara
Fermilab, Batavia, Illinois, USA
B.T. Freemire
IIT, Chicago, Illinois, USA
T.L. Hart
UMiss, University, Mississippi, USA
A.V. Kochemirovskiy
University of Chicago, Chicago, Illinois, USA
T.H. Luo
LBNL, Berkeley, California, USA

Funding: Supported by the US Department of Energy Office of Science through the Muon Accelerator Program.
We report operational experience from the prototype RF module for the Muon Ionization Cooling Experiment (MICE) with final production couplers at Fermilab's MuCool Test Area. This is the last step in fully qualifying the RF modules for operation in the experiment at RAL.

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MOPMY007

Mechanical Design and 3-D Coupled RF, Thermal-Structural Analysis of Normal Conducting 704 MHz and 2.1 GHz Cavities for LEReC Linac

cavity, simulation, vacuum, software

525

J.C. Brutus, S.A. Belomestnykh, I. Ben-Zvi, M. Blaskiewicz, J.M. Brennan, A.V. Fedotov, M.C. Grau, C. Pai, L. Snydstrup, J.E. Tuozzolo, B. P. Xiao, T. Xin, W. Xu, A. Zaltsman
BNL, Upton, Long Island, New York, USA
V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
Two normal conducting cavities operating at 704 MHz and 2.1 GHz will be used for the Low Energy RHIC electron Cooling (LEReC) under development at BNL to improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon. The single cell 704 MHz cavity and the 3-cell 2.1 GHz third harmonic cavity will be used in LEReC to correct the energy spread introduced in the SRF cavity. The successful operation of normal RF cavities has to satisfy both RF and mechanical requirements. 3-D coupled RF-thermal-structural analysis has been performed on the cavities to confirm the structural stability and to minimize the frequency shift resulting from thermal and structural expansion. In this paper, we will present an overview of the mechanical design, results from the RF-thermal-mechanical analysis, progress on the fabrication and schedule for the normal conducting RF cavities for LEReC.

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MOPMY013

Design Study of Collector for CEPC 650 MHz Klystron

gun, klystron, simulation, interface

540

S.C. Wang, D.D. Dong, S. Fukuda, G. Pei, O. Xiao, .. Zaib-un-Nisa, Z.S. Zhou
IHEP, Beijing, People's Republic of China
S. Fukuda
KEK, Ibaraki, Japan

This paper presents the design and simulation of collector for CEPC 650 MHz high-power CW klystron. Power dissipation in collector is optimised by universal beam spread curve using EGUN code, and beam trajectory in collector is verified by Magic code. The thermal analysis is done by ANSYS-CFX, and groove number and water flow rate are optimized by fluid-solid coupled heat transfer simulation.

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MOPMY027

Preliminary Design of High-efficiency Klystron for Pohang Accelerator Laboratory (PAL)

cavity, klystron, beam-losses, simulation

557

S.J. Park, J.Y. Choi, Y.D. Joo, K.R. Kim, W. Namkung, C.D. Park
PAL, Pohang, Kyungbuk, Republic of Korea
M.-H. Cho, J.H. Hwang, T. Seong
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: Supported by the Ministry of Science, ICT and Future Planning of Korea.
Klystrons for particle accelerators are typically designed to have narrow bandwidths with center frequencies ranging from several hundreds (e.g., 350) MHz to X-band (11.424 GHz). Output powers are from several tens of kW to ~1 MW for CW klystrons and ~100 MW for pulsed ones. The narrow-bandwidth requirement has enabled them to provide high gain (typically 40 - 50 dB) which greatly simplifies the RF drive system. Recently, especially for large-scale accelerator facilities, the klystron efficiency has become one of the most demanding issues. This is because electricity cost occupies a great portion of their operating budgets and the klystron efficiency is one of the important factors determining the electricity consumption of the whole accelerator system. In this regard, we have designed a high-efficiency klystron for use in the PLS-II and PAL XFEL at PAL. The basic scheme is to re-design the cavity system to include multi-cell output cavity. In this article, we report on our preliminary design work to determine major cavity parameters including cell frequencies, inter-cell distances, and coupling to external circuits (coupling beta).

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MOPMY031

Development of a 500 MHz Solid-state RF Amplifier as a Combination of Ten Modules

status, interface, rf-amplifier, factory

563

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

The recent development of semiconductor technology has proved that a solid-state RF amplifier is an attractive alternative high-power RF source for numerous accelera-tor applications. Because of the great redundancy and reliability of solid-state amplifiers present in many facili-ties worldwide, the development of a kW-level RF power per module using compact planar baluns has also been undertaken in NSRRC. Ten amplifier modules are com-bined to achieve stable output power 8 kW as an initial conceptual realization of a basic power unit within a combined network. This article describes each portion of the amplifier with the experimental results.

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MOPMY037

GaN Class-F Power Amplifier for Klystron Replacement

klystron, vacuum, electron, controls

583

A.V. Smirnov
RadiaBeam Systems, Santa Monica, California, USA
R.B. Agustsson, S. Boucher, D.I. Gavryushkin, J.J. Hartzell, K.J. Hoyt, A.Y. Murokh, T.J. Villabona
RadiaBeam, Santa Monica, California, USA

Funding: This work was supported by the U.S. Department of Energy (award No. DE-SC0013136)
The vacuum-tube-based RF amplifiers are relatively inefficient and becoming obsolete as the RF world has been progressively converting to solid state technology. Currently, the JLAB upgrade program requires 340 amplifiers capable of 8 kW CW at 1497 MHz while operating at more than 55-60% efficiency to replace their klystrons. Here we explore the possibility of a klystron replacement employing high electron mobility packaged GaN transistors applied in an array of Class-F amplifiers. The inputs and outputs of the many modules needed to make a complete amplifier are connected via precise, in-phase, low-loss, broadband, combiners-dividers. We describe early prototypes of the amplifiers as well as the combiners-dividers and discuss the design features and challenges of such a scheme. This approach can be applied to other national facilities and also for replacement of the klystrons in Middle Energy Electron-Ion Collider which requires about 1.8 MW CW power in total to be produced at 952.6 MHz frequency including 2x12.5 kW power for "crabbing" and 0.53 MW for electron cooling.

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MOPOR008

Beam Induced RF Heating in LHC in 2015

impedance, injection, vacuum, monitoring

602

B. Salvant, O. Aberle, M. Albert, R. Alemany-Fernandez, G. Arduini, J. Baechler, M.J. Barnes, P. Baudrenghien, O.E. Berrig, N. Biancacci, G. Bregliozzi, J.V. Campelo, F. Carra, F. Caspers, P. Chiggiato, A. Danisi, H.A. Day, M. Deile, D. Druzhkin, J. F. Esteban Müller, S. Jakobsen, J. Kuczerowski, A. Lechner, R. Losito, A. Masi, N. Minafra, E. Métral, A.A. Nosych, A. Perillo Marcone, D. Perini, S. Redaelli, F. Roncarolo, G. Rumolo, E.N. Shaposhnikova, J.A. Uythoven, C. Vollinger, A.J. Välimaa, N. Wang, M. Wendt, J. Wenninger, C. Zannini
CERN, Geneva, Switzerland
M. Bozzo
INFN Genova, Genova, Italy
J.F. Esteban Müller
EPFL, Lausanne, Switzerland
N. Wang
IHEP, Beijing, People's Republic of China

Following the recurrent beam induced RF issues that perturbed LHC operation during LHC Run 1, a series of actions were put in place to minimize the risk that similar issues would occur in LHC Run 2: longitudinal impedance reduction campaign and/or improvement of cooling for equipment that were problematic or at the limit during Run 1, stringent constraints enforced on new equipment that would be installed in the machine, tests to control the bunch length and longitudinal distribution, additional monitoring of temperature, new monitoring tools and warning chains. This contribution reports the outcome of these actions, both successes as well as shortcomings, and details the lessons learnt for the future runs.

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MOPOR010

Impedance Measurements and Simulations on the TCTP and TDI LHC Collimators

impedance, HOM, simulation, embedded

610

N. Biancacci, F. Caspers, A. Grudiev, J. Kuczerowski, I. Lamas Garcia, A. Lechner, E. Métral, A. Passarelli, A. Perillo Marcone, B. Salvant, J.A. Uythoven
CERN, Geneva, Switzerland
O. Frasciello, M. Zobov
INFN/LNF, Frascati (Roma), Italy
A. Mostacci
Rome University La Sapienza, Roma, Italy
N. Mounet
EPFL, Lausanne, Switzerland

The LHC collimation system is a critical element for the safe operation of the LHC machine and is subject to continuous performance monitoring, hardware upgrade and optimization. In this work we will address the impact on impedance of the upgrades performed on the TDI injection protection collimator, where the absorber material has been changed to mitigate the device heating observed in machine operation, and on selected secondary (TCS) and tertiary (TCT) collimators, where beam position monitors (BPM) have been embedded for faster jaw alignment. Concerning the TDI, we will present the RF measurements performed before and after the upgrade, comparing the result to heating and tune shift beam measurements. For the TCTs, we will study how the higher order modes (HOM) introduced by the BPM addition have been cured by means of ferrite placement in the device. The impedance mitigation campaign has been supported by RF measurements whose results are in good agreement with GdfidL and CST simulations. The presence of undamped low frequency modes is proved not to be detrimental to the safe LHC operation.

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MOPOR022

Beam Dynamics Observations of the 2015 High Intensity Scrubbing Runs at the Cern Sps

electron, octupole, injection, emittance

648

H. Bartosik, G. Iadarola, K.S.B. Li, L. Mether, A. Romano, G. Rumolo, M. Schenk
CERN, Geneva, Switzerland

Beam quality degradation caused by e-cloud effects has been identified as one of the main performance limitations for high intensity LHC beams with 25 ns bunch spacing in the SPS. In view of the beam parameters targeted with the LHC injectors upgrade (LIU) project, about two weeks of SPS machine time in 2015 were devoted to dedicated scrubbing runs with high intensity LHC 25 ns and dedicated 'doublet' beams in order to study the achievable reduction of e-cloud effects and quantify the consequent beam performance improvements. This paper describes the main observations concerning the coherent instabilities and beam dynamics limitations encountered as well as a detailed characterisation of the performance reach with the highest beam intensity presently available from the pre-injectors.

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MOPOW001

Status of the 1.3 GeV Booster Synchrotron for Generating High Energy Gamma Rays at Tohoku University

vacuum, controls, dipole, booster

701

F. Hinode, H. Hama, S. Kashiwagi, T. Muto, I. Nagasawa, K. Nanbu, Y. Shibasaki, K. Takahashi, C. Tokoku
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

The reconstruction work of accelerator complex for the Great East Japan Earthquake in March 2011 had been conducted in Research Center of Electron Photon Science, Tohoku University. Since restoration of the user machine time in 2013, the approved beam time have been regularly implemented as scheduled. Currently, the 1.3 GeV Booster STorage (BST) ring has been well utilized to generate the high energy gamma-rays as before the disaster. The high energy gamma-rays were produced via Bremsstrahlung by inserting an internal target wire to the beam orbit after the beam acceleration. Since the user machine time was recovered, there were some improvements so far, i.e. realignment of synchrotron magnets, orbit correction in energy ramping process by updating the control of power supplies for steering magnets etc., which brought an increase of the beam current in the maximum energy. Present operational status and recent progress of beam performance in the BST ring are reported.

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MOPOW007

Parts Tracking for Fabrication, Installation and Maintenance at the European XFEL

status, database, controls, monitoring

719

L. Hagge, J.A. Dammann, A. Frank, J. Kreutzkamp, D. Käfer, B. List, S. Rohwedder
DESY, Hamburg, Germany

DESY has established a powerful configuration management solution for the construction of the European XFEL. It tracks the status and location of accelerator components during fabrication and installation, and it contains workflows for reviews, change control and the handling of non-conformities. It provides extensive progress monitoring and reporting for the production and installation of accelerator components. This way, it collects on-the-fly a comprehensive documentation of the accelerator, which serves as a thorough foundation for asset and maintenance management during the upcoming operation. The poster gives an overview of the application and summarizes its status, benefits and experience.

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MOPOW010

The Superconducting Soft X-ray Free-Electron Laser User Facility FLASH

FEL, photon, laser, electron

729

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

FLASH, the superconducting free-electron laser at DESY delivers up to several thousand photon pulses per second with wavelengths ranging from 52 nm down to as low as 4.2 nm and with pulse energies of up to 500 uJ to photon users at the FLASH1 beamline. In 2014 and 2015 a second beamline, FLASH2, has been commissioned in parallel to user operation at FLASH1. FLASH produces bunch trains of up to 800 bunches in 0.8 ms with a train repetition rate of 10 Hz. Each train can be split in sub-trains for FLASH1 and FLASH2, such that both beamlines receive bursts of bunches with full 10 Hz. Operational highlights are the latest SASE energy record of 600 uJ at 15 nm in FLASH2, and the first simultaneous SASE lasing of three undulator systems: FLASH1 (13.7 nm), sFLASH (38 nm), and FLASH2 (20 nm). sFLASH is the seeding experiment in the FLASH1 beamline. Moreover we will report on recent technical and operational improvements. A major success is the improved reliability and stability of the whole facility with shorter SASE tuning times.

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MOPOW015

Fermi Upgrade Plans

FEL, laser, electron, linac

744

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

FERMI has reached its nominal performance on both FEL lines, FEL-1 (12 eV to 62 eV) and FEL-2 (62 eV to 310 eV). After a brief overview of the activities with users, we will describe plans for LINAC , FEL and beamline upgrades for 2016-2018 and beyond. This includes EEHG schemes for FEL-2.

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MOPOW018

Feasibility Study of Photocathode Opearation of Thermionic RF Gun at KU-FEL

FEL, cathode, electron, gun

754

H. Zen, T. Kii, K. Masuda, K. Morita, T. Murata, T. Nogi, H. Ohgaki, S. Suphakul, K. Torgasin
Kyoto University, Kyoto, Japan
R. Kuroda
AIST, Tsukuba, Ibaraki, Japan

Kyoto University Free Electron Laser (KU-FEL) is a mid-infrared FEL driven by a compact linac utilizinig a thermionic RF gun as its electron source*. Recently we succeeded in operating KU-FEL with photocathode operation of the RF gun by using the thermionic cathode (LaB6) as a photocathode. The performance of KU-FEL under the thermionic cathode and photocathode operation will be reported. In addition, some recent application experiment results will also be presented in this presentation.
*H. Zen, et al., Infrared Phys. Techn. 51 (2008) 382.

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MOPOW054

The 4th Harmonic Cavity for Hefei Light Source-II

cavity, HOM, storage-ring, synchrotron

837

C.-F. Wu, S. Dong, G. Huang, D. Jia, K. Jin, C. Li, J.Y. Li, W. Li, J.G. Wang, L. Wang, W. Xu, K. Xuan
USTC/NSRL, Hefei, Anhui, People's Republic of China
R.A. Bosch
UW-Madison/SRC, Madison, Wisconsin, USA
G.Y. Kurkin, E. Rotov
BINP SB RAS, Novosibirsk, Russia
G. Ya
Budker Institute of Nuclear Physics, Novosibirsk, Russia

The 4th harmonic cavity has been firstly used in the storage ring for HLS-II. The paper presents the physics design, developing process and the experimental results for commision. The measurment results show that rf parameters are reasonable. The 4th harmonic cavity efficiently lengthen the bunch and increase the beam life-time. Specially, the beam instablity has been supressed.

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MOPOY006

Preparations for Upgrading the RF Systems of the PS Booster

cavity, impedance, feedback, emittance

853

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

The accelerators of the LHC injector chain need to be upgraded to provide the HL-LHC beams. The PS Booster, the first synchrotron in the LHC injection chain, uses three different RF systems (first, second and up to tenth harmonic) in each of its four rings. As part of the LHC Injector Upgrade the current ferrite RF systems will be replaced with broadband Finemet cavities, increasing the flexibility of the RF system. A Finemet test cavity has been installed in Ring 4 to investigate its effect on machine performance, especially beam stability, during extensive experimental studies. Due to large space charge impedance Landau damping is lost through most of the cycle in single harmonic operation, but is recovered when using the second harmonic and controlled longitudinal emittance blow-up. This paper compares beam parameters during acceleration with and without the Finemet test cavity. Comparisons were made using beam measurements and simulations with the BLonD code based on a full PS Booster impedance model. This work, together with simulations of future operation, have provided input for the decision to adopt a fully Finemet RF system.

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MOPOY010

Simulations and Measurements of Stopbands in the Fermilab Recycler

simulation, resonance, space-charge, proton

864

R. Ainsworth, P. Adamson, K.J. Hazelwood, I. Kourbanis, E.G. Stern
Fermilab, Batavia, Illinois, USA

Fermilab has recently completed an upgrade to the complex with the goal of delivering 700 kW of beam power as 120 GeV protons to the NuMI target. A major part of boosting beam power is to use the Fermilab Recycler to stack protons. Simulations focusing on the betatron resonance stopbands are presented taking into account different effects such as intensity and chromaticity. Simulations are compared with measurements.

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MOPOY017

Upgrade of the Universal Linear Accelerator UNILAC for FAIR

DTL, ion, emittance, rfq

880

L. Groening, A. Adonin, X. Du, R. Hollinger, E. Jäger, M.T. Maier, S. Mickat, A. Rubin, B. Schlitt, G. Schreiber, H. Vormann, C. Xiao, A. Yakushev, C. Zhang
GSI, Darmstadt, Germany
M. Baschke, H. Hähnel, H. Podlech, U. Ratzinger, A. Seibel, R. Tiede
IAP, Frankfurt am Main, Germany
Ch.E. Düllmann, P. Scharrer
HIM, Mainz, Germany

In order to meet the requirements on beam parameters for the upcoming FAIR facility at GSI, the injector linac UNILAC will be upgraded. The activities comprise development of the sources for stable provision of intense uranium beams at a repetition rate of 2.7 Hz, a revision of the beam dynamics layout of the 120 keV/u RFQ, the replacement of the matching section to the 1.4 MeV/u pre-stripper DTL, and enhancement of the gaseous stripping section efficiency. This section shall also include a round-to-flat emittance adaptor to prepare the beam for injection into the synchrotron SIS18 which has a flat transverse injection acceptance. Finally, the upgrade includes the complete replacement of the 40 year old 11.4 MeV/u Alvarez-type post-stripper DTL with a new DTL, preferably using Alvarez-type cavities with improved beam focusing features, as well as its rf-power alimentations.

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MOPOY019

Status of the First CH-Cavities for the New Superconducting CW Heavy Ion LINAC@GSI

resonance, cavity, linac, ion

886

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

In the field of Super Heavy Elements (SHE) a superconducting (sc) continuous wave (cw) high intensity heavy ion LINAC is highly desirable. Currently a multi-stage R&D program conducted by GSI, HIM and IAP* is in progress. The baseline linac design composes a high performance ion source, a new low energy beam transport line, a (cw) upgraded High Charge State Injector (HLI), and a matching line (1.4 MeV/u) followed by the new sc-DTL LINAC for acceleration up to 7.3 MeV/u. The commissioning of the first CH cavity (Demonstrator), in a horizontal cryo module with beam is a major milestone in 2016**. The advanced demonstrator comprises constant-beta sc Crossbar-H-mode (CH) cavities operated at 217 MHz. Presently, the first two sc CH cavities of the advanced demonstrator are under construction at Research Instruments (RI), Bergisch Gladbach, Germany. A string of cavities and focusing elements build from several short CH-cavities with 8 gaps, without girders is recommended. The new design potentially reduces the overall technical risks during the fabrication and the pressure sensitivity through stiffening brackets. The present status of the first two sc cavities will be presented.
* W.Barth et al., Further R&D for a new Superconducting cw Heavy Ion LINAC@GSI, IPAC'14
**F.Dziuba et al., Measurements on the Superconducting 217 MHz CH Cavity during the Manufacturing Phase, SRF2015

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MOPOY020

Prototype Design of a Newly Revised CW RFQ for the High Charge State Injector at GSI

rfq, simulation, resonance, impedance

889

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

Within the scope of the FAIR project (Facility for Antiproton and Ion Research) at GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, the front end of the existing High Charge State Injector (HLI) is planned to be upgraded for cw operation. The required newly revised 4-Rod RFQ structure is currently being designed at the Institute for Applied Physics (IAP) of the Goethe University of Frankfurt. It will be operated with a 100 kW power amplifier at 108 MHz. At first instance a dedicated 4-stem prototype, which is based on the RFQ design for MYRRHA* and FRANZ**, is planned to be manufactured in order to validate the simulated RF performance, thermal behavior and mechanical characteristics in continuous operation. The RF simulations as well as basic thermal simulations are done using CST Studio Suite. In order to prevent oscillations of the electrodes mechanical eigenmodes are analyzed using ANSYS Multiphysics. In addition the ANSYS software allows more sophisticated simulations regarding the cooling capability by considering fluid dynamics in water cooling channels, thus providing a more detailed thermal analysis.
*C. Zhang, H. Podlech, New Reference Design of the European ADS RFQ Accelerator For MYRRHA, IPAC2014
**M. Heilmann et al., A Coupled RFQ-IH Cavity for the Neutron Source FRANZ, IPAC2013

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MOPOY048

A Novel Approach in the One-Dimensional Phase Retrieval Problem and its Application to the Time Profile Reconstruction

electron, optics, FEL, laser

955

F. Bakkali Taheri, J. Cowley, G. Doucas, S.M. Hooker, I.V. Konoplev
JAI, Oxford, United Kingdom
R. Bartolini
DLS, Oxfordshire, United Kingdom

Funding: This work was supported (in parts) by the UK Science and Technology Facilities Council (STFC UK) grant ST/M003590/1 and The Leverhulme Trust through International Network Grant IN-2015-012
Accurate knowledge of the longitudinal profile of the bunch is important in the context of linear colliders, wake-field accelerators and for the next generation of light sources. As a result the non-destructive, single-shot evaluation of the profile is one of the challenging problems which can be addressed via spectral analysis of coherent radiation generated by a charged particle bunch. To reconstruct the bunch profile from the spectrum the phase retrieval problem has to be solved. Frequently applied methods, e.g. minimal phase retrieval or other iterative algorithms, are reliable if the Blaschke phase contribution is negligible. This is neither known a priori nor can it be assumed to apply to an arbitrary bunch profile. We present a novel approach which gives reproducible, most-probable and stable reconstructions for bunch profiles that would otherwise remain unresolved by the existing techniques. The algorithm proposed uses the output of Kramers-Kronig minimum phase as both initial and boundary conditions, providing a unique solution. To assure a converging solution, new conditions linked to the independently known experimental data such as beam charge were introduced.

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MOPOY050

Beam Commissioning Plan of the FRIB Superconducting Linac

linac, cavity, optics, simulation

961

Y. Zhang, C.P. Chu, Z.Q. He, M. Ikegami, S.M. Lidia, S.M. Lund, F. Marti, G. Shen, Y. Yamazaki, Q. Zhao
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The FRIB superconducting linac will deliver all heavy ion beams with energy above 200 MeV/u, and beam power on target up to 400 kW for generation of short lived isotopes. Beam commissioning is the first step to prepare and tune the superconducting linac for high power operation. A staged beam commissioning plan of the FRIB linac is developed, and complete beam tuning practices segment by segment through the entire linac are introduced, which include phase scan signature matching of the superconducting cavities, longitudinal beam matching, transverse matching with horizontal-vertical beam coupling, and beam optics corrections of achromatic and isochronous folding segments up to the second order for acceleration and transport of multi charge state beams.

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MOPOY054

Status of the ESS RFQ

rfq, vacuum, cavity, status

974

D. Chirpaz-Cerbat, A. Albéri, A.C. Chauveau, M. Lacroix, N. Misiara, G. Perreu, O. Piquet, H. Przybilski, N. Sellami
CEA/IRFU, Gif-sur-Yvette, France
N. Berton, G. Bourdelle, M. Desmons, A.C. France, V.M. Hennion, P.-A. Leroy, B. Pottin
CEA/DSM/IRFU, France

The ESS Radio-Frequency Quadrupole (RFQ) is a 4-vanes resonant cavity designed at the frequency of 352.21 MHz. It must accelerate and bunch a 70mA proton beams from 75keV to 3.62MeV with a 4% duty cycle. The RFQ design has already been done, and documented in other papers. This one will present the global status of the RFQ, with technical solutions cho-sen for the main components (for fabrication and op-eration) and the present status of the RFQ fabrication.

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TUXA01

Status and Future Upgrade of J-PARC Accelerators

linac, injection, extraction, hadron

999

M. Kinsho
JAEA/J-PARC, Tokai-mura, Japan

The linac energy reached to 400 MeV as a design value and also a beam current was upgraded to 50 mA by replacing a new ion source. At the 3 GeV synchrotron, a high power beam of 8.41x10¹³ protons per pulse was demonstrated, which was equivalent to 1 MW when the repetition would be 25 Hz. At the main ring, beam loss was reduced by suppression of transverse instabilities and so on. The beam power for both the neutrino experiment and hadron experimental facility is increasing to reduce beam loss. J-PARC accelerators each have their own upgrade plan to increase beam power. The progress and future plan of J-PARC accelerators are reported in this paper.

Slides TUXA01 [11.427 MB]

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TUOAA01

Operation of LANSCE Linear Accelerator with Double Pulse Rate and Low Beam Losses

beam-losses, linac, DTL, proton

1004

Y.K. Batygin, J.S. Kolski, R.C. McCrady, L. Rybarcyk
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by US DOE under contract DE-AC52-06NA25396
In 2014 LANSCE accelerator facility return to 120 Hz pulse rate operation after long period of operation at 60 Hz pulse rate. Increased capabilities require careful tuning of all components of linear accelerator. Transformation to double pulse rate resulted in re-evaluation of tuning procedures in order to meet new challenges in beam operation. The paper summarizes experimental activity on sustaining of high productivity of accelerator facility while keeping beam losses along accelerator at the low level.

Slides TUOAA01 [14.886 MB]

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TUOAA02

Status and Performance of ORNL Spallation Neutron Source Accelerator Systems

linac, rfq, ion-source, ion

1007

Y.W. Kang, A.V. Aleksandrov, D.E. Anderson, M.S. Champion, M.T. Crofford, J. Galambos, B. Han, S.-H. Kim, S.W. Lee, J. Moss, V.V. Peplov, C. Piller, M.A. Plum, R.T. Roseberry, J.P. Schubert, A.P. Shishlo, M.P. Stockli, C.M. Stone, R.F. Welton, M. Wezensky, D.C. Williams, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA
L.A. Longcoy, M. Magda, M.E. Middendorf, W.S. Passmore, C.C. Peters, J. Price, R.B. Saethre, J. Saunders
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
The Spallation Neutron Source (SNS) accelerator sys-tems have been performing continuously and progressively since commissioning in 2006 to deliver the neutrons to beamlines. The 1.4 MW design beam power has been demonstrated during 24/7 operation while developments and investigations for system improvements are still ongoing to achieve the full design beam power and availability. Numerous difficulties that impeded reaching the full performance of the SNS accelerator systems have been identified and are being eliminated through repairs, upgrades, and developments. In this report, operational performance and developments of the accelerator systems are presented along with the efforts for future upgrades of the SNS.

Slides TUOAA02 [5.410 MB]

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TUOBA02

ER@CEBAF - A High Energy, Multi-pass Energy Recovery Experiment at CEBAF

linac, experiment, optics, electron

1022

F. Méot, I. Ben-Zvi, Y. Hao, P. Korysko, C. Liu, M.G. Minty, V. Ptitsyn, G. Robert-Demolaize, T. Roser, P. Thieberger, N. Tsoupas
BNL, Upton, Long Island, New York, USA
M.E. Bevins, S.A. Bogacz, D. Douglas, C.J. Dubbe, T.J. Michalski, F.C. Pilat, Y. Roblin, T. Satogata, M. Spata, C. Tennant, M.G. Tiefenback
JLab, Newport News, Virginia, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A high-energy, multiple-pass energy recovery (ER) experiment proposal, using CEBAF, is in preparation by a JLab-BNL collaboration. The experiment will be proposed in support of the electron-ion collider project (EIC) R&D going on at BNL. This new experiment extends the 2003, 1-pass, 1 GeV CEBAF-ER demonstration into a range of energy and recirculation passes commensurate with BNL's anticipated linac-ring EIC parameters. The experiment will study ER and recirculating beam dynamics in the presence of synchrotron radiation, provide opportunity to develop and test multiple-beam diagnostic instrumentation, and can also probe BBU limitations. This paper gives an overview of the ER@CEBAF project, its context and preparations.

Slides TUOBA02 [1.936 MB]

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TUOCA01

LCLS Bunch Compressor Configuration Study for Soft X-ray Operation

bunching, electron, laser, linac

1037

S. Li, Y. Ding, Z. Huang, A. Marinelli, T.J. Maxwell, D.F. Ratner, F. Zhou
SLAC, Menlo Park, California, USA
C. Behrens
DESY, Hamburg, Germany

The microbunching instability (MBI) is a well-known problem for high brightness electron beams and has been observed at accelerator facilities around the world. Free-electron lasers (FELs) are particularly susceptible to MBI, which can distort the longitudinal phase space and increase the beam's slice energy spread (SES). Past studies of MBI at the Linac Coherent Light Source (LCLS) relied on optical transition radiation to infer the existence of microbunching. With the development of the x-band transverse deflecting cavity (XTCAV), we can for the first time directly image the longitudinal phase space at the end of the accelerator and complete a comprehensive study of MBI, revealing both detailed MBI behavior as well as insights into mitigation schemes [1]. The fine time resolution of the XTCAV also provides the first LCLS measurements of the final SES, a critical parameter for many advanced FEL schemes. Detailed MBI and SES measurements can aid in understanding MBI mechanisms, benchmarking simulation codes, and designing future high-brightness accelerators.

Slides TUOCA01 [4.436 MB]

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TUOCA03

Commissioning of the European XFEL Injector

gun, emittance, laser, controls

1044

F. Brinker
DESY, Hamburg, Germany

The European XFEL Injector consists of an L-Band RF photoinjector, a TESLA type 1.3 GHz module, a 3rd harmonic RF section, a laser heater and an extensive diagnostic section to determine projected and slice properties of the beam. The commissioning of the complete system has been started in December 2015 after several years of construction. We will report on commissioning results and persepctives for the later XFEL operation.

Slides TUOCA03 [5.182 MB]

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TUZB01

High Power Proton Beam Targets: Technological Evolution, Current Challenges, and the Future

target, neutron, proton, radiation

1075

J. Galambos
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 talk reviews the history of proton beam target development and the current challenges associated with the operation of high power beam targets. Beyond providing high power proton beams, accelerator facilities must also engineer robust targets to accept the load and satisfy mission needs. Recently some high power facilities are limited by target operations, rather than accelerator capabilities. The outlook for targets for future high power facilities is also considered.

Slides TUZB01 [8.971 MB]

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TUPMB017

The Injection Septum Magnet for the Collector Ring (FAIR)

injection, septum, vacuum, lattice

1145

P.Yu. Shatunov, D.E. Berkaev, I. Koop, E.P. Semenov, D.B. Shwartz
BINP SB RAS, Novosibirsk, Russia
A. Dolinskyy, S.A. Litvinov
GSI, Darmstadt, Germany
Yu. A. Rogovsky
Budker INP & NSU, Novosibirsk, Russia

Collector Ring is one of the key installations of the FAIR project (Darmstadt, Germany). It is dedicated for stochastic cooling of incoming beams of antiprotons and rare ions. Additionally there is a mode of operation for experiments in the ring. Beams for all modes of operation are injected through one transfer channel. Extremely high acceptance of the ring (240 mm*mrad) leads to large apertures of all magnetic elements including the septum magnet. Meanwhile planned parameters of the magnetic field and magnetic field quality are comparatively strict. The present state of the design of the pulsed injection septum for the CR is presented in this article together with the concept of the injection system.

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TUPMB026

Magnet System for a Compact Microtron

microtron, permanent-magnet, vacuum, electron

1164

S.A. Kahn, R.J. Abrams, M.A.C. Cummings, R.P. Johnson, G.M. Kazakevich
Muons, Inc, Illinois, USA

Funding: Funded by DOE SBIR grant DE-SC0013795
A compact microtron can be an effective gamma source that can be transported to locations outside the laboratory. As part of a Phase I project we have studied a portable microtron that can accelerate electrons with energies of 6 MeV and above as a source for gamma and neutron production. The mass of the magnet is a significant contribution to the overall mass of the system. This paper will discuss conceptual designs for both permanent magnet and electromagnet systems. The choice of mictrotron RF frequency range is determined by the application requirements. The RF frequency influences the size of the microtron magnet and consequently its weight. We have looked at how the design would vary with the different frequency configurations.

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TUPMB033

Design and Construction of the QC2 Superconducting Magnets in the SuperKEKB IR

solenoid, quadrupole, superconducting-magnet, focusing

1174

N. Ohuchi, Y. Arimoto, N. Higashi, M. Iwasaki, M.K. Kawai, Y. Kondo, K. Tsuchiya, X. Wang, H. Yamaoka, Z.G. Zong
KEK, Ibaraki, Japan
H.K. Kono, T. Murai, S. Takagi
Mitsubishi Electric Corp., Energy Systems Centre, Kobe, Japan

SuperKEKB is now being constructed with a target luminosity of 8×10³⁵ which is 40 times higher than the KEKB luminosity. The luminosity can be achieved by the "Nano-Beam" accelerator scheme, in which both beams should be squeezed to about 50 nm at the beam interaction point, IP. The beam final focusing system consists of 8 superconducting quadrupole magnets, 4 superconducting solenoids and 43 superconducting corrector coils. The QC2 magnets are designed to be located in the second closest position from IP as the final beam focusing system of SuperKEKB. The two types of quadrupole magnets have been designed for the electron and positron beam lines. The QC2P for the positron beam is designed to generate the field gradient, G, of 28.1 T/m and the effective magnetic length, L, of 0.4099 m at the current, I, of 877.4 A. The QC2E for the electron beam line is designed to generate G=28.44 T/m and L=0.537 mm, 0.419 mm (for QC2LE, QC2RE) at I=977 A. In the paper, we will present the designs and the constructions of the two types of the quadrupole magnets.

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TUPMB034

Design and Manufacture of a Superconducting Solenoid for D-Line of J-PARC Muon Facility

solenoid, vacuum, interface, radiation

1177

T. Semba, Y. Hagiwara, S. Kido, S. Nakajima, Y. Tanaka
Hitachi Ltd., Ibaraki-ken, Japan
N. Kawamura, Y. Makida, Y. Miyake, H. Ohhata, K. Sasaki, K. Shimomura
KEK, Ibaraki, Japan
N. Kurosawa
KEK, Tokai Branch, Tokai, Naka, Ibaraki, Japan
Y. Murata
Hitachi, Ltd., Energy and Environmental System Laboratory, Hitachi-shi, Japan
P. Strasser
High Energy Accelerator Research Organization (KEK), Institute of Materials Structure Science (IMSS), Ibaraki, Japan

A superconducting solenoid for J-PARC muon facility was newly designed and manufactured. High Energy Accelerator Research Organization (KEK) has been operating the J-PARC Muon Science Establishment (MUSE) since 2008. Among its four muon beam lines, the decay muon line (D-Line) has been extracting and providing surface muons and positive decay muons up to a momentum of 50 MeV/c for various users, utilizing a superconducting solenoid. The D-Line as well as the other J-PARC facility suffered severe damages from the earthquake on March 11, 2011. It necessitated rebuilding of the damaged superconducting solenoid. New design parameter of the solenoid is as follows: length of solenoid: 6 m, diameter of warm bore: 0.2 m, magnetic field of bore center: 3.5 T, rated current: 415 A, superconducting wire: NbTi/Cu, quench protection: quench back heaters. The six-meter-long solenoid consists of twelve pieces of 0.5-meter-long superconducting coils. The entire solenoid is forced-indirectly cooled by supercritical helium flow. This report describes the design and manufacturing process of the newly built superconducting solenoid for D-Line of J-PARC muon facility.

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TUPMB035

Developments of HTS Magnets towards Application to Accelerators

dipole, neutron, target, cyclotron

1180

K. Hatanaka, M. Fukuda, K. Kamakura, H. Ueda, Y. Yasuda, T. Yorita
RCNP, Osaka, Japan

We have been developing magnets utilizing first generation HTS wire for this decade. HTS materials have advantages over LTS materials. Magnets can be operated at 20 K or higher temperature and the cooling structure becomes simpler. Owing to a large margin in operating temperature, it is possible to excite HTS magnets by AC or pulsed currents without quenching. After successful performance tests of proto type models, two magnets have been fabricated for practical use. A cylindrical magnet generates a magnetic field higher than 3.5 T at the center to polarized 210 neV neutrons. A dipole magnet is excited by pulse currents in order to deliver accelerated beams to two target stations by time sharing. Their design and operational performance are discussed.

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TUPMB038

Degradation of the Insulation of the LHC Main Dipole Cable when Exposed to High Temperatures

dipole, superconducting-magnet, laser, high-voltage

1186

V. Raginel, B. Auchmann, D. Kleiven, R. Schmidt, A.P. Verweij, D. Wollmann
CERN, Geneva, Switzerland

Funding: Research supported by the High Luminosity LHC project
The energy stored in the LHC beams is substantial and requires a complex machine protection system to protect the equipment. Despite efficient beam absorbers, several failure modes lead to some limited beam impact on superconducting magnets. Thus it is required to understand the damage mechanisms and limits of superconducting magnets due to instantaneous beam impact. This becomes even more important due to the future upgrade of CERNs injector chain for the LHC that will lead to an increase of the beam brightness. A roadmap to perform damage tests on magnet parts has been presented previously*. The polyimide insulation of the superconducting cable is identified as one of the critical elements of the magnet. In this contribution, the experimental setup to measure the insulation degradation of LHC main dipole cables due to exposure to high temperature is described. Compressed stacks of insulated Nb-Ti cables have been exposed to a heat treatment within an Argon atmosphere. After each heat treatment, high-voltage measurements verified the dielectric strength of the insulation. The results of this experiment provide an upper damage limit of superconducting magnets due to beam impact.
* Experimental Setups to Determine the Damage Limit of Superconducting Magnets for Instantaneous Beam Losses, V. Raginel et al, IPAC'15

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TUPMB040

LHC Accelerator Fault Tracker - First Experience

cryogenics, hardware, ion, luminosity

1190

A. Apollonio, L. Ponce, C. Roderick, R. Schmidt, B. Todd, D. Wollmann
CERN, Geneva, Switzerland

Availability is one of the key performance indicators of LHC operation, being directly correlated with integrated luminosity production. An effective tool for availability tracking is a necessity to ensure a coherent capture of fault information and relevant dependencies on operational modes and beam parameters. At the beginning of LHC Run 2 in 2015, the Accelerator Fault Tracking (AFT) tool was deployed at CERN to track faults or events affecting LHC operation. Information derived from the AFT is crucial for the identification of areas to improve LHC availability, and hence LHC physics production. For the 2015 run, the AFT has been used by members of the CERN Availability Working Group, LHC Machine coordinators and equipment owners to identify the main contributors to downtime and to understand the evolution of LHC availability throughout the year. In this paper the 2015 experience with the AFT for availability tracking is summarised and an overview of the first results as well as an outlook to future developments is given.

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TUPMR019

Measurements of the Beam Phase Response to Correcting Magnetic Fields in PSI Cyclotrons

cyclotron, simulation, diagnostics, proton

1271

A.S. Parfenova, C. Baumgarten, J.M. Humbel, A.C. Mezger
PSI, Villigen PSI, Switzerland
A.V. Petrenko
CERN, Geneva, Switzerland

The cyclotron-based proton accelerator facility (HIPA) at PSI is presently operated at 1.3-1.4 MW beam power at a kinetic energy of 590 MeV/u to drive the neutron spallation source SINQ and for production of pion and muon beams. Over the years HIPA facility has developed towards increase of the delivered beam current and beam power (0.1 mA in 1974 till 2.2 mA in 2010). During the last few years several upgrades of the Ring cyclotron field correction and beam phase monitoring systems were made. RF voltage was also increased. In order to test the performance of the upgraded system the phase response measurements were carried out.

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TUPMR025

Design of the LBNF Beamline

target, proton, shielding, extraction

1291

V. Papadimitriou, K. Ammigan, J.E. Anderson, K. Anderson, R. Andrews, V.T. Bocean, C.F. Crowley, N. Eddy, B.D. Hartsell, S. Hays, P. Hurh, J. Hylen, J.A. Johnstone, P.H. Kasper, T.R. Kobilarcik, G.E. Krafczyk, B.G. Lundberg, A. Marchionni, N.V. Mokhov, C.D. Moore, D. Pushka, I.L. Rakhno, S.D. Reitzner, P. Schlabach, V.I. Sidorov, A.M. Stefanik, S. Tariq, L.R. Valerio, K. Vaziri, G. Velev, G.L. Vogel, K.E. Williams, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
C.J. Densham
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

Funding: Work supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The Long Baseline Neutrino Facility (LBNF) will utilize a beamline located at Fermilab to provide and aim a neutrino beam of sufficient intensity and appropriate energy range toward DUNE detectors, placed deep underground at the SURF Facility in South Dakota. The primary proton beam (60 - 120 GeV) will be extracted from the MI-10 section of Fermilab's Main Injector. Neutrinos are produced after the protons hit a solid target and produce mesons which are subsequently focused by magnetic horns into a 194 m long decay pipe where they decay into muons and neutrinos. The parameters of the facility were determined taking into account the physics goals, spacial and radiological constraints and the experience gained by operating the NuMI facility at Fermilab. The Beamline facility is designed for initial operation at a proton-beam power of 1.2 MW, with the capability to support an upgrade to 2.4 MW. LBNF/DUNE obtained CD-1 approval in November 2015. We discuss here the design status and the associated challenges as well as the R&D and plans for improvements before baselining the facility.

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TUPMR032

Initial Commissioning of the Rutherford Appleton Laboratory (RAL) Scaled Negative Penning Ion Source

interface, plasma, cathode, space-charge

1314

D.C. Faircloth, S.R. Lawrie, T. Rutter, M. Whitehead, T. Wood
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

A new high duty factor, scaled Penning surface plasma source is being developed at RAL. This paper provides initial commissioning results. A stable high-current (up to 100 A) pulsed discharge is obtained, but the anode overheats, caused by poor thermal contact at elevated temperatures. The overheating anode yields a noisy discharge, with low output current, and makes high duty factor operation impossible. The performance of a thermal interface material for aperture plate (plasma electrode) cooling is detailed. An update on the cathode heaters is provided. The anode to source-body fit is analysed at different temperatures for different combinations of mechanical tolerances. This offers insights when compared to ISIS operational sources. A new anode with modified tolerance dimensions for improved fit is being manufactured and will be tested in June 2016.

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TUPMR039

The Development of a New High Field Injection Septum Magnet System for Main Ring of J-Parc

injection, septum, power-supply, flattop

1337

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. It is necessary to exchange a high field injection septum magnet which will be installed at the injection line from RCS to MR and its power supply, because the current injection septum system can not be operated with 1.3 second repetition. Since confirmed the large leakage field around current circling beam line of the injection magnet, we must improve the shielding structure which make low leakage field. We started the development of the new injection septum magnet and its power supply in 2013. It can operate with 1 Hz repetition and the low leakage field which its order is 10^-4 of the gap field. The new Injection septum magnet and the new power supply were constructed in Winter of 2014. We had many improvement of the magnet and power supply. We will install the new injection septum magnet system in this summer. In this presentation, we will report the detail of the results of its performance.

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TUPMR040

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

septum, power-supply, vacuum, extraction

1340

T. Shibata, K. Ishii, H. Matsumoto, N. Matsumoto, T. Sugimoto
KEK, Ibaraki, Japan
K. Fan
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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TUPMR049

Feasibility Study of the PS Injection for 2 GeV LIU Beams with an Upgraded KFA-45 Injection Kicker System Operating in Short Circuit Mode

simulation, injection, kicker, flattop

1363

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

Under the scope of the LIU project the CERN PS Booster to PS beam transfer will be modified to match the requirements for the future 2 GeV beams. This paper describes the evaluation of the proposed upgrade of the PS injection kicker. Different schemes of an injection for LIU beams into the PS have been outlined in the past already under the aspect of individual transfer kicker rise and fall time performances. Homogeneous rise and fall time requirements in the whole PSB to PS transfer chain have been established which allowed to consider an upgrade option of the present injection kicker system operated in short circuit mode. The challenging pulse quality constraints require an improvement of the flat top and post pulse ripples. Both operation modes, terminated and short circuit mode are analysed and analogue circuit simulations for the present and upgraded system are outlined. Recent measurements on the installed kickers are presented and analysed together with the simulation data. First measurements verifying the performance of upgrade options have been taken during the last end of the year stop. The paper concludes with an upgrade plan and a brief overview of implementation risks.

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TUPMR053

Initial Experience with Carbon Stripping Foils at ISIS

injection, synchrotron, proton, vacuum

1378

B. Jones, D.J. Adams, H. V. Smith
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS Facility at the Rutherford Appleton Laboratory is a spallation neutron and muon source based upon a 50 Hz rapid cycling synchrotron accelerating ~3×10¹³ protons per pulse from 70 to 800 MeV to deliver a mean beam power of 0.2 MW to two target stations. Throughout its 30 years of operation ISIS has developed aluminium oxide foils in-house for H− charge exchange injection. The manufacturing and installation processes for these foils are time consuming, radiologically dose intensive and require a high degree of skill. Commercially available carbon based foils commonly used at other facilities, have the potential to greatly simplify foil preparation and installation in addition to improving beam quality. Similar foils would also be necessary for facility upgrades which increase injection energy to withstand the higher operating temperatures. This paper describes the initial experience of carbon foils in the ISIS synchrotron including issues relating to handling and mounting foils, their performance under beam operation and plans for further development.

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TUPMR057

High Current Proton and Carbon Beam Operation via Stripping of a Molecular Beam at GSI UNILAC

proton, ion, linac, ion-source

1390

M. Heilmann, A. Adonin, W.A. Barth, Ch.E. Düllmann, R. Hollinger, E. Jäger, P. Scharrer, W. Vinzenz, H. Vormann
GSI, Darmstadt, Germany
W.A. Barth, Ch.E. Düllmann, P. Scharrer
HIM, Mainz, Germany
Ch.E. Düllmann
Johannes Gutenberg University Mainz, Institut of Nuclear Chemistry, Mainz, Germany
P. Scharrer
Mainz University, Mainz, Germany

The experimental program of the future facility for Antiproton and Ion Research (FAIR) project requires a high number of cooled anti-protons per hour. The FAIR proton injector linac has to deliver a 70 MeV, 35 mA pulsed proton beam at a repetition rate of 4 Hz. During recent machine investigations at the GSI a high current proton beam was achieved in the Universal Lineral Accelerator (UNILAC). In preparation for this the ion source was equipped with a newly developed 7-hole extraction system and optimized for single charged hydrocarbon beam (isobutane gas) operation. This beam was accelerated to 1.4 MeV/u and cracked in a new pulsed gas stripper into protons and charged carbon. The new stripper setup injects high density gas pulses synchronous with the transit of the beam pulse close to the beam trajectory. With this setup a proton (up to 4.3 mA) as well a carbon beam (up to 9.5 mA) intensity record at beam energy of 1.4 MeV was achieved. The proton beam was accelerated up to 3.6 MeV/u inside the first Alvarez-section with full transmission. The paper will present beam measurement in comparison to the former beam investigations using a 2 mA proton beam in the entire UNILAC.

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TUPMW012

Beam Offset Stabilization Techniques for the LHC Collision Points

luminosity, experiment, optics, ground-motion

1438

A.A. Gorzawski, R. Jacobsson, J. Wenninger
CERN, Geneva, Switzerland

Maintaining head-on collisions over many hours is an important aspect of optimizing the performance of a collider. For current LHC operation where the beam optics is fixed during periods of colliding beam, mainly ground motion induced perturbations have to be compensated. The situation will become significantly more complex when luminosity leveling will be applied following the LHC luminosity upgrades. During β^* leveling the optics in the interaction region changes significantly, feed-downs from quadrupole misalignment may induce significant orbit changes that may lead to beam offsets at the collision points. Such beam offsets induce a loss of luminosity and reduce the stability margins for collective effects that is provided by head-on beam-beam. It is therefore essential that the beam offsets at the collision points are minimized during the leveling process. This paper will review sources and mitigation techniques for the orbit perturbation at the collision points during β^* leveling, and present results of experiments performed at the LHC to mitigate and compensate such offsets.

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TUPMW014

Improved Aperture Measurements at the LHC and Results from their Application in 2015

alignment, injection, insertion, beam-losses

1446

P.D. Hermes, R. Bruce, M. Fiascaris, H. Garcia, M. Giovannozzi, A. Mereghetti, D. Mirarchi, E. Quaranta, S. Redaelli, B. Salvachua, G. Valentino
CERN, Geneva, Switzerland
R. Kwee-Hinzmann
Royal Holloway, University of London, Surrey, United Kingdom
E. Quaranta
Politecnico/Milano, Milano, Italy

A good knowledge of the available aperture in the LHC is essential for a safe operation due to the risk of magnet quenches or even damage in case of uncontrolled beam losses. Experimental validations of the available aperture are therefore crucial and were in the past carried out by either a collimator scan combined with beam excitations or through the use of local orbit bumps. In this paper, we show a first comparison of these methods in the same machine configuration, as well as a new very fast method based on a beam-based collimator alignment and a new faster variant of the collimator scan method. The methods are applied to the LHC operational configuration for 2015 at injection and with squeezed beams and the measured apertures are presented.

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TUPMW017

Electron Cloud Observations during LHC Operation with 25 ns Beams

electron, injection, simulation, cryogenics

1458

K.S.B. Li, H. Bartosik, G. Iadarola, L. Mether, A. Romano, G. Rumolo, M. Schenk
CERN, Geneva, Switzerland

While during the Run 1 (2010-2012) of the Large Hadron Collider (LHC) most of the integrated luminosity was produced with 50 ns bunch spacing, for the Run 2 start-up (2015) it was decided to move to the nominal bunch spacing of 25 ns. As expected, with this beam configuration strong electron cloud effects were observed in the machine, which had to be mitigated with dedicated 'scrubbing' periods at injection energy. This enabled to start the operation with 25 ns beams at 6.5 TeV, but e-cloud effects continued to pose challenges while gradually increasing the number of circulating bunch trains. This contribution will review the encountered limitations and the mitigation measures that where put in place and will discuss possible strategies for further performance gain.

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TUPMW023

Macroparticle-Induced Losses During 6.5 TeV LHC Operation

proton, electron, beam-losses, luminosity

1481

G. Papotti, M. Albert, B. Auchmann, E.B. Holzer, M.K. Kalliokoski, A. Lechner
CERN, Geneva, Switzerland

One of the major performance limitations for operating the LHC at high energy was feared to be the so called UFOs (Unidentified Falling Objects, presumably micrometer sized dust particles which lead to fast beam losses when they interact with the beam). Indeed much higher rates were observed in 2015 compared to Run 1, and about 20 fills were prematurely terminated by too high losses caused by such events. Additionally they triggered a few beam induced quenches at high energy, the first in the history of the LHC. In this paper we review the latest update on the analysis of these events, e.g. the conditioning observed during the year and possible correlations with beam and machine parameters. At the same time we also review the optimization of beam loss monitor thresholds in terms of machine protection and availability.

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TUPMW026

Feed-Forward Corrections for Tune and Chromaticity Injection Decay During 2015 LHC Operation

injection, hadron, collider, octupole

1489

M. Solfaroli Camillocci, M. Juchno, M. Lamont, M. Schaumann, E. Todesco, J. Wenninger
CERN, Geneva, Switzerland

After two years of shutdown, the Large Hadron Collider (LHC) has been operated in 2015 at 6.5 TeV, close to its designed energy. When the current is stable at low field, the harmonic components of the main circuits are subject to a dynamic variation induced by current redistribution on the superconducting cables. The Field Description of the LHC (FiDel) foresaw an increase of the decay at injection of tune (quadrupolar components) and chromaticity (sextupolar components) of about 50% with respect to LHC Run1 due to the higher operational current. This paper discusses the beam-based measurements of the decay during the injection plateau and the implementation and accuracy of the feed-forward corrections as present in 2015. Moreover, the observed tune shift proportional to the circulating beam intensity and it's foreseen feed-forward correction are covered.

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TUPMW027

The 2015 Heavy-Ion Run of the LHC

luminosity, ion, experiment, heavy-ion

1493

J.M. Jowett, R. Alemany-Fernandez, R. Bruce, M. Giovannozzi, P.D. Hermes, W. Höfle, M. Lamont, T. Mertens, S. Redaelli, M. Schaumann, J.A. Uythoven, J. Wenninger
CERN, Geneva, Switzerland

In late 2015 the LHC collided lead nuclei at a beam energy of 6.37 Z TeV, chosen to match the 5.02 TeV per colliding nucleon pair of the p-Pb collision run in 2013. In so doing, it surpassed its design luminosity by a factor of 2. Besides the higher energy, the operational configuration had a number of new features with respect to the previous Pb-Pb run at 3.5 Z TeV in 2011; unusual bunch patterns providing collisions in the LHCb experiment for the first time, luminosity levelling and sharing requirements, a vertical displacement of the interaction point in the ALICE experiment, and operation closer to magnet quench limits with mitigation measures. We present a summary of the commissioning and operation and what has been learned in view of future heavy-ion operation at higher luminosity.

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TUPMW030

Review of LHC On-line Model Implementation and of its Applications

optics, quadrupole, database, interface

1505

T. Persson, J.M. Coello de Portugal, M. Fjellstrom, L. Malina, J. Roy, P.K. Skowroński, A. Szczotka
CERN, Geneva, Switzerland
J.S. Moeskops
RID, Delft, The Netherlands

The online model of the LHC aims to provide an accurate description of the machine at any given time. In order to do so it extracts the current optics in the machine along with other crucial parameters. It also provides the functionality to match the measured orbit using virtual correctors and the measured beta functions using virtual quadrupoles. In this way an accurate effective model can be created. In order to facilitate the use of the online model a graphical user interface has been developed. In this article we describe the design of the online model and its application in different studies. We give examples how it has been used to predict the influence of changes before they were applied to the machine.

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TUPMW031

Combined Ramp and Squeeze to 6.5 TeV in the LHC

optics, controls, dipole, betatron

1509

M. Solfaroli Camillocci, S. Redaelli, R. Tomás, J. Wenninger
CERN, Geneva, Switzerland

The cycle of the LHC is composed of an energy ramp followed by a betatron squeeze, needed to reduce the beta- star value in the interaction points. Since Run 1, studies have been carried out to investigate the feasibility of combining the two operations, thus considerably reducing the duration of the operational cycle. In Run 2, the LHC is operating at the energy of 6.5 TeV that requires a much longer cycle than that of Run 1. Therefore, the performance gains from a Combined Ramp and Squeeze (CRS) is more interesting. Merging the energy ramp and the betatron squeeze could result in a gain of several minutes for each LHC cycle. With increasing maturity of LHC operation, it is now possible to envisage more complex beam manipulations; this paper describes the first machine experiment with beam, aiming at validating the combination of ramp and squeeze, which was performed in 2015, during a machine development phase. The operation experience with the LHC run at 2.51 TeV, when CRS down to 4 meters was deployed and a the first results of 2016 run are also reviewed.

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TUPMW038

RHIC Operation with Asymmetric Collisions in 2015

proton, injection, emittance, cavity

1527

C. Liu, E.C. Aschenauer, G. Atoian, M. Blaskiewicz, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, W. Fischer, C.J. Gardner, X. Gu, T. Hayes, H. Huang, R.L. Hulsart, J.S. Laster, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, G. Narayan, S.K. Nayak, S. Nemesure, P.H. Pile, A. Poblaguev, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, W.B. Schmidke, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, G. Wang, K. Yip, A. Zaltsman, K. Zeno, S.Y. Zhang
BNL, Upton, Long Island, New York, USA
S.M. White
ESRF, Grenoble, France

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Collisions with beams of highly asymmetric rigidities (proton-Gold and proton-Aluminum) were provided for the RHIC physics programs in 2015. Magnets were moved for the first time in RHIC prior to the run to accommodate the asymmetric beam trajectories during acceleration and at store. A special ramping scheme was designed to keep the revolution frequencies of the beams in the two rings equal. The unique operational experience of the asymmetric run will be reviewed.

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TUPMY005

A Muon Source Proton Driver at JPARC-based Parameters

proton, injection, booster, linac

1550

D.V. Neuffer
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the U. S. Department of Energy.
An "ultimate" high intensity proton source for neutrino factories and/or muon colliders was projected to be a ~4 MW multi-GeV proton source providing short, intense proton pulses at ~15 Hz. The JPARC ~1 MW accelerators provide beam at parameters that in many respects overlap these goals. Proton pulses from the JPARC Main Ring can readily meet the pulsed intensity goals. We explore these parameters, describing the overlap and consider extensions that may take a JPARC-like facility toward this "ultimate" source. JPARC itself could serve as a stage 1 source for such a facility.

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TUPOR008

Effect of the Various Impedances on Longitudinal Beam Stability in the CERN SPS

impedance, HOM, simulation, vacuum

1666

A. Lasheen, T. Argyropoulos, J. Repond, E.N. Shaposhnikova
CERN, Geneva, Switzerland

The High Luminosity (HL)-LHC project at CERN aims at a luminosity increase by a factor ten and one of the necessary ingredients is doubling the bunch intensity to 2.4x10¹¹ ppb for beams with 25 ns bunch spacing. Many improvements are already foreseen in the frame of the LHC Injector Upgrade (LIU) project, but probably this intensity would still not be reachable in the SPS due to longitudinal instabilities. Recently a lot of effort went into finding the impedance sources of the instabilities. Particle simulations based on the latest SPS impedance model are now able to reproduce the measured instability thresholds and were used to determine the most critical impedance sources by removing them one by one from the model. It was found that impedance of vacuum flanges and of the already damped 630 MHz HOM of the main RF system gave for 72 bunches the comparable intensity thresholds. Possible intensity gains are defined for realistic impedance modifications and for various beam configurations (number of bunches, longitudinal emittances) and RF programs (single and double RF). The results of this study are used as a guideline for planning of a new campaign of the SPS impedance reduction.

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TUPOR016

A Multi-GeV Recirculating Proton Linac

proton, linac, cavity, acceleration

1688

J. Qiang
LBNL, Berkeley, California, USA

A high power GeV proton linac has many scientific applications. Recirculating RF linac as an efficient accelerator has been used and proposed to accelerate both electron and muon beams. In this paper, we propose using a multi-pass recirculating RF linac to attain a multi-GeV high power proton beam. This linac consists of three types of superconducting RF cavities that accelerate the proton beam multiple times from 150 MeV to final multiple GeV energy. Such a recirculating linac can significantly reduce the number of RF cavities in the accelerator and lower the cost of the facility.

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TUPOR026

Final Design and Status of the Third Recirculation for the S-DALINAC*

recirculation, dipole, linac, electron

1717

M. Arnold, T. Kürzeder, N. Pietralla
TU Darmstadt, Darmstadt, Germany
F. Hug
IKP, Mainz, Germany

Funding: *Work supported by DFG through CRC 634 and RTG 2128
Since 1991 the twice-recirculating superconducting accelerator S-DALINAC is providing electron beams for nuclear physics experiments. Due to a reduced quality factor of its cavities in comparison to their design values it was not possible to operate the accelerator with its maximum design energy of 130 MeV in cw mode. To provide electron beams of this energy in the future it was decided to add one recirculation beam line in order to use the main linac four times, operating the cavities on decreased accelerating gradients. The necessary modifications consist of several different aspects: A new beamline needs to be installed and other pre-existing beam line sections have to be modified for matching new boundary conditions. These new conditions are mainly a result of beam dynamics simulations and of the design of a new separation dipole magnet, which will bend the different beams energy-dependent in the various recirculation beam lines. We will present the implemented design and give a status report on the project.

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TUPOW003

High Average RF Power Tests With 2 RF Vacuum Windows at PITZ

gun, vacuum, Windows, emittance

1744

Y. Renier, G. Asova, M. A. Bakr, P. Boonpornprasert, J.D. Good, M. Groß, C. Hernandez-Garcia, H. Huck, I.I. Isaev, D.K. Kalantaryan, M. Krasilnikov, O. Lishilin, G. Loisch, D. Malyutin, D. Melkumyan, A. Oppelt, M. Otevřel, G. Pathak, T. Rublack, I.V. Rybakov, F. Stephan, G. Vashchenko, Q.T. Zhao
DESY Zeuthen, Zeuthen, Germany
M. Bousonville, S. Choroba, S. Lederer
DESY, Hamburg, Germany

The Photo Injector Test facility at DESY, Zeuthen site (PITZ), was built with the aim to develop and characterize electron sources for future usage at FLASH and at the European XFEL. Recently, the main focus at PITZ has been the study of gun reliability and photoinjector performance at high average power. The goal is to get stable and reliable operation with 6.4 MW peak power in the gun at 650 us RF pulse length and 10 Hz repetition rate. To achieve this, a new RF feed system with two RF windows was installed at PITZ in 2014. During this test, the old gun 4.2 with a modified back-plane design for better cathode contact has been used. In this contribution the results of the RF conditioning of gun 4.2 with a detailed interlock analysis will be reported as well as results from recent electron beam characterization.

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TUPOW005

Update on Third Harmonic XFEL Activities at INFN LASA

cavity, HOM, pick-up, diagnostics

1751

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

After the successful installation and beam operation of the first batch of 3.9 GHz cavities into the XFEL Third Harmonic Injector Module, ten more cavities have been tested and delivered to DESY to be assembled into a spare cryomodule. In this paper, we report on the activities related to the cavities fabrication, treatment and vertical testing at INFN LASA.

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TUPOW036

Recent Developments and Operational Status of the Compact ERL at KEK

linac, emittance, laser, gun

1835

T. Obina, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondo, T. Konomi, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, S. Sasaki, K. Satoh, Y. Seimiya, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, N. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
KEK, Ibaraki, Japan
R. Hajima, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
QST, Tokai, Japan
M. Kuriki
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan

The Compact Energy Recovery Linac (cERL) at KEK is a test accelerator in order to develop key components to realize remarkable ERL performance as a future light source. After the beam commissioning in December 2013, the legal current limit has been increased step-by-step like 1 uA, 10 uA, and 100 uA. Survey for the source of beam losses has been conducted in each step, and the study on beam dynamics and tuning has also been carried out. As a next step, 1 mA operation is scheduled in February 2016. In parallel to the increase in beam current, a laser Compton scattering (LCS) system which can provide high-flux X-ray to a beamline has been successfully commissioned. We report recent progress in various kinds of beam tuning: improvement of electron gun performance, high bunch charge operation, mitigation of beam losses, LCS optics tuning and bunch compression for THz radiation.

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TUPOW038

Measurement and Control of Beam Losses Under High Average-current Operation of the Compact ERL at KEK

radiation, beam-losses, recirculation, optics

1839

S. Sakanaka, K. Haga, Y. Honda, H. Matsumura, T. Miyajima, T. Nogami, T. Obina, H. Sagehashi, M. Shimada, M. Yamamoto
KEK, Ibaraki, Japan

The compact ERL (cERL)* is a superconducting accelerator aimed at demonstrating excellent ERL technologies for the future light source. The cERL comprises a 5 MeV injector, a main linac, and a recirculation loop. In the cERL, production and transportation of low-emittance and high average-current beams (tentative goals: 1 mm-mrad and 10 mA) is primarily important. At this moment (in December 2015), beam currents of up to 80 uA (CW) have successfully been transported through the recirculation loop at a beam energy of 20 MeV. Before such high-current operations, we carefully tuned up the machine so that beam losses became very small. The beam losses were watched using fast beam-loss detectors and radiation monitors while absolute losses were estimated from measured radiation levels on the roof of the shield. After careful beam-optics corrections and elimination of beam halos / tails at low-energy section, we achieved the beam losses of at most a few nA level at several locations along the loop, and those below 1 nA elsewhere in the loop. We will report these results together with the result of higher-current operation which is planned early in 2016.
* S. Sakanaka et al., IPAC'15, TUBC1; T. Obina et al., to be presented at IPAC'16.

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TUPOW039

Simulation Study of the Beam Halo Formation for Beam Loss Estimation and Mitigation at KEK Compact ERL

simulation, cavity, electron, gun

1843

O. Tanaka, T. Miyajima, N. Nakamura, T. Obina, M. Shimada, R. Takai
KEK, Ibaraki, Japan

Funding: Work supported by the "Grant-in-Aid for Creative Scientific Research" of JSPS (KAKENHI 15K04747)
At KEK Compact ERL (cERL) we are aiming to produce high-current and low-emittance electron beams (up to 10 mA) without significant beam loss. We believe that beam halo makes a significant impact into the beam loss. Therefore, we are performing beam loss simulations to meet the results of the beam loss measurements*. In particular, a simulation of the bunch tail originated from the electron gun was performed to understand the mechanisms of the beam halo formation. Since some measured beam profiles demonstrated unexpected halo particles, several factors such as misalignment of beam line elements and kicks from the steering coils were added into the simulation. Simulation study results are compared with the related beam loss and halo measurements here.
* Sakanaka et al., these proceedings

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TUPOW043

Electron Beam Dynamics Studies for ELI-NP GBS Linac

electron, linac, beam-loading, photon

1857

A. Giribono, F. Cardelli, L. Palumbo, L. Piersanti
University of Rome La Sapienza, Rome, Italy
D. Alesini, A. Gallo, C. Vaccarezza, A. Vannozzi
INFN/LNF, Frascati (Roma), Italy
A. Bacci, C. Curatolo, I. Drebot, V. Petrillo, A.R. Rossi, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
G. Campogiani
Rome University La Sapienza, Roma, Italy
F. Cardelli, L. Piersanti
INFN-Roma1, Rome, Italy
L. Palumbo
INFN-Roma, Roma, Italy

The ELI-NP Gamma Beam System is an advanced gamma ray source based on the Compton back-scattering effect with unprecedented specifications of brilliance ( >10²¹), monochromaticity (0.5%) and energy tunability (0.2 - 19.5 MeV), presently under construction in Magurele-Bucharest (RO). Here the head-on collision is foreseen between an intense high power laser beam and a high brightness high quality electron beam with a maximum kinetic energy of 740 MeV. The electron beam dynamics analysis and control for the ELI-NP GBS Linac in the single and multi bunch mode have been investigated and are here illustrated.

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TUPOY001

Beam Quality Assurance for Proton Clinical Beams at MedAustron

proton, controls, hardware, synchrotron

1899

L.C. Penescu, F. Farinon, A. Garonna, M. Kronberger, T.K.D. Kulenkampff, C. Kurfürst, S. Myalski, S. Nowak, F. Osmić, M.T.F. Pivi, C. Schmitzer, P. Urschütz, A. Wastl
EBG MedAustron, Wr. Neustadt, Austria

The commissioning process of the MedAustron accelerator has delivered the configurations providing the requested beam parameters in the irradiation room, and at the same time it identified the critical points where a performance drift can appear. The strategy for beam quality assurance has therefore two components: testing the specific parameters of the beam delivered to the irradiation room, and testing for any drifts that might appear at the critical points. We present here the monitoring strategy, the observed limitations, the tools employed and the long-term statistics of the beam quality assurance for proton clinical beams.

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TUPOY004

Recommissioning of the Marburg Ion-beam Therapy Centre (MIT) Accelerator Facility

ion, proton, synchrotron, extraction

1908

U. Scheeler, Th. Haberer, C. Krantz, S.T. Sievers, M.M. Strohmeier
MIT, Marburg, Germany
R. Cee, E. Feldmeier, M. Galonska, K. Höppner, J.M. Mosthaf, A. Peters, S. Scheloske, C. Schömers, T.W. Winkelmann
HIT, Heidelberg, Germany

The Marburg Ion-Beam Therapy Centre (MIT), located in Marburg, Germany, is in clinical operation since 2015. MIT is designed for precision cancer treatment using beams of protons or carbon nuclei, employing the raster scanning technique. The accelerator facility consists of a linac-synchrotron combination, developed by Siemens Healthcare/Danfysik, that was in a state of permanent stand-by upon purchase. With support from its Heidelberg-based sister facility HIT, the MIT operation company (MIT Betriebs GmbH) recommissioned the machine in only 13 months, reaching clinical standards of beam quality delivered to all four beam outlets. With the first medical treatment in October 2015, MIT became the third operational hadron beam therapy centre in Europe offering both proton and carbon beams.

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TUPOY024

Wave Particle Cherenkov Interactions Mediated via Novel Materials

simulation, acceleration, electron, scattering

1960

A. Hopper
IIAA, Huddersfield, United Kingdom
R. Seviour
University of Huddersfield, Huddersfield, United Kingdom

Currently there is an increasing interest in dielectric wall accelerators. These work by slowing the speed of an EM wave to match the velocity of a particle beam, allowing wave-beam interactions, accelerating the beam. However conventional dielectric materials have limited interaction regions, so wave-beam energy transfer is minimal. In this paper we consider Artificial Materials (AMs), as slow wave structures, in the presence of charged particle beams to engineer Inverse-Cherenkov acceleration. AMs are periodic constructs whose properties depend on their subwavelength geometry rather than their material composition, and can be engineered to give an arbitrary dispersion relation. We show that Metamaterials, one example of an AM, can mediate an Inverse-Cherenkov interaction, but break down in high power environments due to high absorption. We consider AMs with low constitutive parameters and show they can exhibit low absorption whilst maintaining the ability to have a user defined dispersion relation, and mediate a wavebeam interaction leading to Inverse-Cherenkov acceleration.

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TUPOY029

Gem*Star Consortium Proposal to Build a Demonstration Accelerator Driven System

target, proton, site, neutron

1973

R.P. Johnson, R.J. Abrams, M.A.C. Cummings, T.J. Roberts
Muons, Inc, Illinois, USA
R.B. Vogelaar
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA

The GEM*STAR Consortium of four companies, two universities, and two US national laboratories has formed Mu*STAR, a new company, to fund and build a profitable pilot plant to demonstrate the advantages of subcritical molten-salt-fueled nuclear reactors driven by superconducting RF proton linacs. The GEM*STAR multipurpose reactor design features new accelerator power capabilities, 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. GEM*STAR is a reactor that without redesign will burn spent nuclear fuel (SNF), 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 design overall, and a strong candidate for export. We describe the design and plans for funding a pilot plant that could profitably dispose of excess weapons-grade plutonium.

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TUPOY042

Schemes for the Accelerator-driven System

proton, cyclotron, neutron, target

1995

T.-Y. Lee, H.-S. Lee, S. Shin
PAL, Pohang, Kyungbuk, Republic of Korea

Accelerator-Driven system (ADS) is considered the fu-ture nuclear reactor. In principle, it is safer and creates less waste than the conventional nuclear reactor, and provides the transmutation function that converts spent fuel into short-lived elements. However, to fully realize this system, a huge proton accelerator (typically, 1 GeV beam energy and over 10 MW beam power) with ex-tremely high operational stability is necessary. This paper discusses how the currently available technology can be applied for nuclear transmutation.

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TUPOY043

GEM*STAR Accelerator-Driven Subcritical System for Improved Safety, Waste Management, and Plutonium Disposition

neutron, proton, target, simulation

1998

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

Operation of high-power SRF particle accelerators at two US national laboratories allows us to consider a less-expensive nuclear reactor that operates without the need for a critical core, fuel enrichment, or reprocessing. A multipurpose reactor design that takes advantage of this new accelerator capability includes an internal spallation neutron target and high-temperature molten-salt fuel with continuous purging of volatile radioactive fission products. 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. We describe GEMSTAR , a reactor that without redesign will burn spent nuclear fuel, natural uranium, thorium, or surplus weapons material. A first application is to burn 34 tonnes of excess weapons grade plutonium as an important step in nuclear disarmament under the 2000 Plutonium Management and Disposition Agreement **. The process heat generated by this W-Pu can be used for the Fischer-Tropsch conversion of natural gas and renewable carbon into 42 billion gallons of low-CO2-footprint, drop-in, synthetic diesel fuel for the DOD.

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TUPOY045

Effect of the Beam Time Structure on the Neutronics of an Accelerator Driven Subcritical Reactor

neutron, proton, controls, target

2004

M. Haj Tahar, F. Méot
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.
When designing a high power accelerator for an ADSR, it is important to optimize the beam parameters to be compatible with the steady state character of the reactor operation and to define an adequate and safe startup procedure. In this study we investigate the impact of the beam time structure on the kinetic behavior of the sub-critical core and derive a general relationship between the time evolution of the neutron population and the proton beam.

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TUPOY055

Study on Electro-polishing of Nb Surface by Periodic Reverse Current Method with Sodium Hydroxide Solution

experiment, cavity, SRF, cathode

2020

J. Taguchi, A. Namekawa
Nomura Plating Co, Ltd., Osaka, Japan
H. Hayano, T. Saeki
KEK, Ibaraki, Japan
C.E. Reece, H. Tian
JLab, Newport News, Virginia, USA

Electropolishing is one of the best methods of Nb surface finishing of the superconducting cavity to obtain high accelerating gradient. Mixed solution of hydrofluoric acid and sulfuric acid is generally used in the electropolishing of Nb. But this solution is very dangerous and because the corrosion of the metal occurs by hydrofluoric acid, all equipment must be made of high density polyethylene or fluorocarbon resin. This causes the expensive cost of electropolishing instrument. In addition, this solution produces sulfur compound on the Nb surface in the electropolishing reaction. This sulfur compound can be field emission sources on the inner surface of cavity and degrades acceleration performance. In this poster, we report noble electropolishing method using periodic reverse current and sodium hydroxide solution. The reaction produces no sulfur content and the equipment is less expensive because the instrument can be made of usual plastic material. As the result of experiments with Nb-coupon samples, we found that the surface roughness is equivalent to the conventional electropolishing method.

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WEZA01

RHIC Performance with Stochastic Cooling for Ions and Head-on Beam-beam Compensation for Protons

luminosity, electron, proton, ion

2055

W. Fischer, J.G. Alessi, Z. Altinbas, E.C. Aschenauer, G. Atoian, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, R. Connolly, M.R. Costanzo, T. D'Ottavio, K.A. Drees, A.V. Fedotov, C.J. Gardner, D.M. Gassner, X. Gu, C.E. Harper, M. Harvey, T. Hayes, J. Hock, H. Huang, R.L. Hulsart, J.P. Jamilkowski, T. Kanesue, N.A. Kling, J.S. Laster, C. Liu, Y. Luo, D. Maffei, Y. Makdisi, M. Mapes, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, T.A. Miller, M.G. Minty, C. Montag, J. Morris, G. Narayan, C. Naylor, S. Nemesure, M. Okamura, S. Perez, A.I. Pikin, P.H. Pile, A. Poblaguev, V. Ptitsyn, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, W.B. Schmidke, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, R. Than, P. Thieberger, J.E. Tuozzolo, B. Van Kuik, G. Wang, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, W. Zhang
BNL, Upton, Long Island, New York, USA
M. Bai, Y. Dutheil
FZJ, Jülich, Germany
S.M. White
ESRF, Grenoble, France

Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
The Relativistic Heavy Ion Collider (RHIC) has two main operating modes with heavy ions and polarized protons respectively. In addition to a continuous increase in the bunch intensity in all modes, two major new systems were completed recently mitigating the main luminosity limit and leading to significant performance improvements. For heavy ion operation stochastic cooling mitigates the effects of intrabeam scattering, and for polarized proton operation head-on beam-beam compensation mitigated the beam-beam effect. We present the performance increases with these upgrades for heavy ions and polarized protons, as well as an overview of all operating modes past and planned.

Slides WEZA01 [12.687 MB]

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WEOCA01

Operation of the LHC with Protons at High Luminosity and High Energy

luminosity, proton, emittance, cryogenics

2066

G. Papotti, M. Albert, R. Alemany-Fernandez, G.E. Crockford, K. Fuchsberger, R. Giachino, M. Giovannozzi, G.H. Hemelsoet, W. Höfle, D. Jacquet, M. Lamont, D. Nisbet, L. Normann, M. Pojer, L. Ponce, S. Redaelli, B. Salvachua, M. Solfaroli Camillocci, R. Suykerbuyk, J.A. Uythoven, J. Wenninger
CERN, Geneva, Switzerland

In 2015 the Large Hadron Collider (LHC) entered the first year in its second long Run, after a 2-year shutdown that prepared it for high energy. The first two months of beam operation were dedicated to setting up the nominal cycle for proton-proton operation at 6.5 TeV/beam, and culminated with the first physics with 3 nominal bunches/ring at 13 TeV CoM on 3 June. The year continued with a stepwise intensity ramp up that allowed reaching 2244 bunches/ring for a peak luminosity of ~5·10³³ cm^-2s⁻¹ and a total of just above 4 fb-1 delivered to the high luminosity experiments. Beam operation was shaped by the high intensity effects, e.g. electron cloud and macroparticle-induced fast losses (UFOs), which on a few occasions caused the first beam induced quenches at high energy. This paper describes the operational experience with high intensity and high energy at the LHC, together with the issues that had to be tackled along the way.

Slides WEOCA01 [4.013 MB]

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WEOCA02

First Operational Experience with an Internal Halo Target at RHIC

target, detector, collider, experiment

2070

C. Montag
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.
An internal halo target has been installed in the STAR detector at RHIC to extend the energy range towards lower energies and increase the event rates in the search for the critical point in the QCD phase diagram. We discuss geometric considerations that led to the present target layout and present first operational results.

Slides WEOCA02 [1.605 MB]

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WEOBB01

Single Micron Single-Bunch Turn-by-Turn BPM Resolution Achieved at NSLS-II

experiment, storage-ring, collective-effects, Windows

2095

B. Podobedov, W.X. Cheng, K. Ha, Y. Hidaka, J. Mead, O. Singh, K. Vetter
BNL, Upton, Long Island, New York, USA

NSLS-II state-of-the-art BPMs provide a single micron turn-by-turn BPM resolution for any bunch train of reasonable intensity. For certain beam dynamics studies a similar, or even better, resolution is desired for a single-, or a few-bunch fill, which is not yet available with our standard BPM signal processing. This paper describes our experience with more advanced BPM ADC signal processing which allowed us to significantly improve turn-by-turn BPM resolution in single bunch mode down to the level of about one micron at ~1 nC/bunch. We also present the examples of machine studies that benefit from this BPM performance enhancement.

Slides WEOBB01 [2.565 MB]

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WEPMB005

Manufacturing of the IFMIF Series Power Couplers

vacuum, interface, cavity, cryomodule

2122

H. Jenhani, N. Bazin, N. Berton, G. Devanz, P. Hardy, V.M. Hennion
CEA/IRFU, Gif-sur-Yvette, France

In the framework of the International Fusion Materials Irradiation Facility (IFMIF), which consists of two high power CW accelerator drivers, each delivering a 125 mA deuteron beam at 40 MeV, a Linear IFMIF Prototype Accelerator (LIPAc) is presently under construction for the first phase of the project. Eight power couplers are needed for the cryomodule of LIPAc. After the validation of the two prototypes, the manufacturing of the Series Power Couplers was lunched. This paper will report the status of the manufacturing progress. It will also describe the acceptance tests in addition to the criteria adopted for these critical RF power units. The manufacturing imperfections and some finishing techniques used for the different parts will be also presented and discussed.

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WEPMB007

Error Estimation in Cavity Performance Test for the European XFEL at DESY

cavity, cryomodule, accelerating-gradient, HOM

2128

Y. Yamamoto
KEK, Ibaraki, Japan
W.-D. Möller, D. Reschke
DESY, Hamburg, Germany

The cavity performance tests, that is, vertical test (V.T.) and cryomodule test (C.T.), in the cavity/cryomodule mass production for XFEL have been done since 2012 at DESY, and is still on-going at present. At the comparatively initial stage of the mass production, the error estimation in the cavity performance tests was done for understanding how precisely those measurements are done at AMTF (Accelerator Module Test Facility). There are two parameters for the error estimation in V.T. One is the cable calibration parameter, and the other is the external Q-value, which is related to the power emitted from cavity. The measurement precision in the external Q-value depends on the measurement of coupling coefficient (β) strongly. Therefore, it is essential not to miss the β measurement for the precise measurement in V.T. On the other hand, as for C.T., the change of parameter (Kt), which is related to the evaluation of accelerating gradient, was used. As the result of the data analysis for Kt, the error was estimated to be 6%, and is related to the cavity performance degradation from V.T. to C.T. In this paper, the detailed data analysis and error estimation will be presented.

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WEPMB009

Status of the Superconducting Cryomodules and Cryogenic System for the Mainz Energy-recovering Superconducting Accelerator MESA

cryomodule, HOM, niobium, electron

2134

T. Stengler, K. Aulenbacher, F. Hug, D. Simon, P. Weber
IKP, Mainz, Germany
F. Schlander
ESS, Lund, Sweden
N. Wiehl
Johannes Gutenberg University Mainz, Institut of Nuclear Chemistry, Mainz, Germany

Funding: Work supported by the German Research Foundation (DFG) under the Cluster of Excellence "PRISMA"
SRF and the cryogenic system are mandatory for the operation of MESA at the Institut für Kernphysik at Johannes Gutenberg-Universität Mainz. The cryomodule production project is running for one year right now and the recent developments and measurements are presented. Further on the cryogenic concept required for the operation of MESA will be discussed.

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WEPMB013

Long Term Cavity Performance in Compact-ERL Injector Cryomodule

cavity, cryomodule, radiation, electron

2145

E. Kako, T. Konomi, T. Miura, H. Sakai, K. Umemori
KEK, Ibaraki, Japan

Degradation of cavity performance due to heavy field emission was observed in three 2-cell cavities after beam operation at 5 MeV for 2 years.

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WEPMB015

Construction and 2K Cooling Test of Horizontal Test Cryostat at KEK

SRF, cavity, cryomodule, HOM

2151

K. Umemori, K. Hara, E. Kako, Y. Kobayashi, Y. Kondo, H. Nakai, H. Sakai, S. Yamaguchi
KEK, Ibaraki, Japan

A horizontal test cryostat was designed and constructed at AR East building on KEK. Main purposes of test stand are improvement of module assembly technique and effective development of module components. Diameter of vacuum chamber is 1 m and its length is 3 m, which is enough to realize performance test of L-band 9-cell cavity with full assembly, including input couplers, HOM dampers/couplers and frequency tuners. On the sides, several ports are prepared to access to components, such as coupler and tuners. A cold box is placed on the top of the chamber. Liquid He is filled in a 4K-pod and 2K He is supplied through a J-T valve. A He pumping system is prepared. Inside of the chamber was covered with 80K shield, which is cooled by Liquid nitrogen. A cavity is supported on 5K table, which is also used as 5K thermal anchors. After cooling down to 80K using liquid Nitrogen, 4K He was stored and pumped down to 2K. The cooling test was successful. In this presentation, details of design and construction of the horizontal test cryostat is described and results of the cooling tests are shown. High power tests will be realized in near future.

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WEPMB016

Vertical Test Results of Nitrogen Doped SRF Cavities at KEK

cavity, vacuum, SRF, monitoring

2154

K. Umemori, H. Inoue, E. Kako, T. Konomi, T. Kubo, H. Sakai, H. Shimizu, M. Yamanaka
KEK, Ibaraki, Japan
H. Hara, K. Sennyu, T. Yanagisawa
MHI-MS, Kobe, Japan

Recently Nitrogen doping(N-doping) technique was proposed and drastic improvements of Q-values were reported. Since high-Q operation of SRF cavities are very attractive for CW machine, we started investigation on performance of Nitrogen doped SRF cavities. Nitrogen doping systems were prepared on two vacuum furnaces, which have been used for annealing of SRF cavities. Two fine grain single cell cavities have been used for the study. After 800 degree, 3 hours annealing, N-doping were carried out under several Pa of Nitrogen pressure and followed by post annealing. Three kind of different conditions, pressure and duration time, were attempted. After applying EP-2, cavity performances were evaluated by vertical tests. Against our expectations, we observed lower Q-values, at every measurements, than those measured without N-doping. In this presentation, we describe details about N-doping system and parameters and results obtained by vertical tests. Some discussions are also given against our results.

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WEPMB021

Construction of Measurement System for Superconducting Characteristics on Thin-film Samples at KEK

cavity, solenoid, experiment, SRF

2167

T. Saeki, H. Hayano, T. Kubo
KEK, Ibaraki, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
H. Oikawa
Utsunomiya University, Utsunomiya, Japan

We set up a measurement system for superconducting characteristics on thin-film samples at KEK. The system includes small-sized and middle-sized cryostats, where critical temperature, critical magnetic field, Residual Resistiviy Ratio (RRR), Superconducting RF (SRF) resistivity can be measured on thin-film samples. A small-sized cryostat has a compact refrigerator to cool down samples for the measurements of critical temperature and RRR. On the other had, we can cool down various setups with a middle-sized cryostat by using liquid helium. A thin-film sample is set into a mushroom cavity and the SRF characteristics of the thin-film sample can be measured. In another setup, a sample is set with a small coil and the third harmonic measurement is done on the sample around the critical temperature. Finally, a thin-film sample is set into the bore-center of superconducting magnet and the magnetization of sample is measured with external magnetic field around the critical temperature. This article presents the details of the system and some measurements of samples by the system.

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WEPMB036

High Pressure Rinsing for Niobium Superconducting Cavity

cavity, niobium, target, SRF

2202

Y. Jung, M.J. Joung, M. Lee
IBS, Daejeon, Republic of Korea
J. Lee, J. Seo
Vitzrotech Co., Ltd., Ansan City, Kyunggi-Do, Republic of Korea

Niobium superconducting cavity is treated with high pressure rinsing to clean the inner surface of the cavity. Either organic or inorganic residues on the inner surface of the cavity can cause serious problems during the cavity operation. A thermal quenching - superconducting material loses its superconductivity - is a typical phenomenon brought out by harmful defects by increasing critical temperature. We have performed high pressure rinsing experiments to check out a prototype HPR machine. HPR experiments were performed with a simplified cavity structure, and analyzed as a function of the pressure, the distance from a nozzle, and the sizes of defects on the niobium surface. In this presentation, we will discuss the performance of the prototype HPR machine.

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WEPMB051

HIE-ISOLDE: First Commissioning Experience

cryomodule, solenoid, controls, cavity

2230

W. Venturini Delsolaro, E. Bravin, N. Delruelle, M. Elias, J.A. Ferreira Somoza, M.A. Fraser, J. Gayde, Y. Kadi, G. Kautzmann, F. Klumb, Y. Leclercq, M. Martino, V. Parma, J.A. Rodriguez, S. Sadovich, E. Siesling, D. Smekens, L. Valdarno, D. Valuch, P. Zhang
CERN, Geneva, Switzerland

The HIE ISOLDE project [1] reached a major milestone in October 2015, with the start of the first physics run with radioactive ion beams. This achievement was the culminating point of intense months during which the first cryomodule of the HIE ISOLDE superconducting Linac and its high-energy beam transfer lines were first installed and subsequently brought into operation. Hardware commissioning campaigns were conducted in order to define the envelope of parameters within which the machine could be operated, to test and validate software and controls, and to investigate the limitations preventing the systems to reach their design performance. Methods and main results of the first commissioning of HIE ISOLDE post accelerator, including the performance of the superconducting cavities with beam, will be reviewed in this contribution.

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WEPMB052

System Integration and Beam Commissioning of the 500-MHz RF Systems for Taiwan Photon Source

SRF, cavity, vacuum, storage-ring

2234

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

The accelerator complex of the Taiwan Photon Source (TPS) consists of two 500-MHz RF systems: one RF system with two KEKB-type single-cell SRF modules is operated for the 3-GeV storage ring of circumference 518 m, and the other with one five-cell Petra cavity at room temperature is for the concentric full-energy booster synchrotron. This report overviews the installation, system integration, commissioning, and initial operation of the 500-MHz RF systems for the TPS with emphasis on our solution to approach the highly reliable SRF operation at its maximum design beam current of 500-mA. Lessons learned during the project are reviewed.

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WEPMB058

LHC Crab Cavity Coupler Test Boxes

HOM, cavity, luminosity, higher-order-mode

2248

J.A. Mitchell
Lancaster University, Lancaster, United Kingdom
R. Apsimon, G. Burt, A.R.J. Tutte
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
R. Calaga, A. Macpherson, E. Montesinos
CERN, Geneva, Switzerland
S.D. Silva
ODU, Norfolk, Virginia, USA
B. P. Xiao
BNL, Upton, Long Island, New York, USA

The LHC double quarter wave (DQW) crab cavities have two different types of Higher Order Mode (HOM) couplers in addition to a fundamental power coupler (FPC). The FPC requires conditioning, so to achieve this we have designed a radio-frequency (RF) quarter wave resonator to provide high transmission between two opposing FPCs. For the HOM couplers we must ensure that the stop-band filter is positioned at the cavity frequency and that peak transmission occurs at the same frequencies as the strongest HOMs. We have designed two test boxes which preserve the cavity spectral response in order to test the couplers.

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WEPMB060

Modifications to the Pump Out Box to Lower the Qext of Diamond SCRF Cavities

cavity, coupling, simulation, electron

2251

S.A. Pande, C. Christou, P. Gu
DLS, Oxfordshire, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

Diamond's CESR-B cavities are iris coupled and have fixed Qext. For reliability, the cavities are operated at lower voltages. This results in the optimum condition for beam loading being satisfied at a much lower power typically about 100 kW. For operation at 300 mA with two cavities, the RF power needed per system exceeds 200 kW. Consequently, the cavities need to be operated under-coupled. To lower the Qext and move the optimum operating point nearer to 200kW, 3 stub tuners are used in the waveguide feed line. The difference in the height of the coupling waveguide on cavity and that of the vacuum side waveguide on the window assembly results in a step transition which affects the Qext. The present window/step location results in Qext higher than that without the window. The Qext can be lowered by re-locating the RF window or by shifting the step change in the waveguide cross-section from its present location. This needs modification to the Pump Out box. The pros and cons of the proposed modification to the pump out box in terms of standing waves and multipacting characteristics studied with CST Studio are discussed in this paper.

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WEPMR005

Investigation of Thermal Acoustic Effects on SRF Cavities within CM1 at Fermilab

cavity, cryomodule, cryogenics, acceleration

2265

M.W. McGee, E.R. Harms, A.L. Klebaner, J.R. Leibfritz, A. Martinez, Y.M. Pischalnikov, W. Schappert
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02- 07CH11359 with the U.S. Department of Energy.
Two TESLA-style 8-cavity cryomodules have been operated at Fermilab Accelerator Science and Technology (FAST), formerly the Superconducting Radio Frequency (SRF) Accelerator Test Facility. Operational instabilities were revealed during Radio Frequency (RF) power studies. These observations were complemented by the characterization of thermal acoustic effects on cavity microphonics manifested by apparent noisy boiling of helium involving vapor bubble and liquid vibration. The thermal acoustic measurements also consider pressure and temperature spikes which drive the phenomenon at low and high frequencies.

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WEPMR008

Mechanical Stability Study for Integrable Optics Test Accelerator at Fermilab

optics, electron, controls, dipole

2274

M.W. McGee, R. Andrews, K. Carlson, J.R. Leibfritz, L.E. Nobrega, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02- 07CH11359 with the U.S. Department of Energy.
The Integrable Optics Test Accelerator (IOTA) is proposed for operation at Fermilab. The goal of IOTA is to create practical nonlinear accelerator focusing systems with a large frequency spread and stable particle motion. The IOTA is a 40 m circumference, 150 MeV (e-), 2.5 MeV (p⁺) diagnostic test ring. A heavy low frequency steel floor girder is proposed as the primary tier for IOTA device component support. Two design lengths; (8) 4 m and (2) 2.8 m long girders with identical cross section completely encompass the ring. This study focuses on the 4 m length girder and the development of a working prototype. Hydrostatic Level Sensor (HLS), temperature, metrology and fast motion measurements characterize the anticipated mechanical stability of the IOTA ring.

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WEPMR011

Simulations and Experimental Studies of Third Harmonic 3.9 Ghz CW Couplers for LCLS-II Project

cavity, simulation, cryomodule, linac

2280

N. Solyak, I.V. Gonin, E.R. Harms, S. Kazakov, T.N. Khabiboulline, A. Lunin
Fermilab, Batavia, Illinois, USA

LCLS-II linac is based on SRF technology developed for the XFEL project. The XFEL 3rd harmonic system built by INFN is based on the original designs of cavity and power coupler developed and built by Fermilab for the FLASH facility at DESY. For LCLS-II application both designs of the 3.9 GHz cavity and the power coupler have been modified for an operation in the continuous wave regime up to 2 kW average RF power. In this paper we discuss coupler modifications and the result multiphysics analysis for various operating regimes. For the initial test of a proposed design, we decided to modify two spare warm sections of power couplers, built for the FLASH facility, by shortening both of two inner bellows and making a thicker copper plating. Modification of the existing coupler test stand and the test program are briefly discussed in this paper.

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WEPMR018

Time Resolved Cryogenic Cooling Analysis of the Cornell Injector Cryomodule

HOM, cryogenics, cryomodule, simulation

2298

R.G. Eichhorn, A.C. Bartnik, B.M. Dunham, G.M. Ge, G.H. Hoffstaetter, H. Lee, M. Liepe, S.R. Markham, T.I. O'Connell, 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

To demonstrate key parameters of a an energy recovery linac (ERL) at Cornel, an injector based on a photo gun and an SRF cryomodule was designed and built. The goal was to demonstrate high current generation while achieving low emittances. While the emittance goal has been reached, the current achieved so far is 75 mA. Even though this is a world record, it is still below the targeted 100 mA. While ramping up the current we observed excessive heating in the fundamental power coupler which we were able to track down to insufficient cooling of the 80 K intercepts. These intercepts are cooled by a stream of parallel cryogenic flows which we found to be unbalanced. In this paper we will review the finding, describe the analysis we did, modeling of the parallel flow and the modifications made to the module to overcome the heating.

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WEPMR038

Frequency Tuning for a DQW Crab Cavity

cavity, simulation, SRF, insertion

2357

S. Verdú-Andrés, I. Ben-Zvi, J. Skaritka, Q. Wu, B. P. Xiao
BNL, Upton, Long Island, New York, USA
K. Artoos, R. Calaga, O. Capatina, R. Leuxe, C. Zanoni
CERN, Geneva, Switzerland
I. Ben-Zvi
Stony Brook University, Stony Brook, USA

Funding: Work supported by US DOE via BSA LLC contract No.DE-AC02-98CH10886, the US LARP program, US DOE contract No. DE-AC02-05CH1123 (NERSC resources) and by HiLumi project.
The nominal operating frequency for the HL-LHC crab cavities is 400.79 MHz within a bandwidth of ±60kHz. Attaining the required cavity tune implies a good understanding of all the processes that influence the cavity frequency from the moment when the cavity parts are being fabricated until the cavity is installed and under operation. Different tuning options will be available for the DQW crab cavity of LHC. This paper details the different steps in the cavity fabrication and preparation that may introduce a shift in the cavity frequency and introduces the different tuning methods foreseen to bring the cavity frequency to meet the specifications.

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WEPMR043

Analysis of Electrical Energy Consumption of Accelerator Reserach Facilities

experiment, HOM, framework, neutron

2370

J. Stadlmann
GSI, Darmstadt, Germany
D. Batorowicz, C. Fuhr, J. Hanson, S. Leis
TUD, Darmstadt, Germany
M. Seidel
PSI, Villigen PSI, Switzerland

Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 312453.
Optimization of energy efficiency and utilization of renewable energy sources has become a major focus of political and social policies, leading to increasing energy cost not only in Germany but also in the European energy market. Simultaneously the energy demand of future accelerator projects is estimated to rise compared to existing facilities, leading to overall increased energy costs. Energy efficiency could counteract this trend by reducing energy consumption for a given research goal. This work aims to find recommendations for saving potential in existing research accelerators as well as guidelines for construction of future facilities. In order to identify and develop key figures for comparison between several international particle accelerator facilities, data has been collected by a questionnaire developed in cooperation between GSI and TUD, Darmstadt. We present the first results of it's evaluation.

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WEPMR044

Beam Induced Damage Studies of the IFMIF/EVEDA 125 mA CW 9 MeV D⁺ Linear Accelerator

ion, proton, neutron, linac

2373

F. Scantamburlo, J. Knaster, A. Marqueta
IFMIF/EVEDA, Rokkasho, Japan
P.-Y. Beauvais
F4E, Germany
B. Bolzon, H. Dzitko
CEA/IRFU, Gif-sur-Yvette, France
R. Ichimiya
JAEA, Aomori, Japan
H. Kobayashi
KEK, Ibaraki, Japan

IFMIF (International Fusion Material Irradiation Facility) will be a Li(d, xn) neutron source providing equivalent neutron spectrum of DT fusion reactions and comparable neutron flux of future commercial reactors. IFMIF, presently in its EVEDA (Engineering Validation and Engineering Design Activities) phase is installing LIPAc (Linear IFMIF Prototype Accelerator) in Rokkasho (Japan), a 125 mA CW 9 MeV deuteron beam as validating prototype of IFMIF accelerators. The MPS of LIPAc manages the interlocks for a fast beam stop during anomalous beam losses or other hazardous situations. High speed processing is essential to achieve MPS goals driven by investment protection principles. Since Bragg's peak depth is dependent of energy, power densities by uncontrolled beam losses can be very damaging at low energies; the MPS principles for LIPAc are validating those for IFMIF. Beam losses may lead to severe damages by excessive thermal stresses, annealing or even burn/melting of materials. Careful studies to set the maximum allowable time for a beam shutdown to prevent undesired scenarios during the accelerator operational life have been undertaken.

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WEPMR053

Technical Overview of Cavity BPM Mover for PAL XFEL

cavity, controls, undulator, EPICS

2395

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

Pohang Accelerator Laboratory(PAL) has been developing a SASE X-ray Free Electron Laser based on 10 GeV linear accelerator. The cavity BPM mover was developed to be used in the intersections of the Undulator Systems. The main specifications include submicron repeatability for a 50 kg cavity BPM adjusting system within compact dimensions and a ±1.5 mm stroke in the vertical and horizontal direction. Compact linear motion guide based on 5-phase stepping motors have been chosen. A closed-loop control system has been developed to achieve this repeatability. For the feedback, one digital probe sensor for each axis was used. Mechanical switches are used to limit movement. In addition, hard-stops are included for emergency. In this report, we describe the design of the stages used for precise movement and results of mechanical measurements including reproducibility will be reported.

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WEPMR055

openSE: a Systems Engineering Framework Particularly Suited to Particle Accelerator Studies and Development Projects

project-management, framework, radiation, electronics

2398

P. Bonnal, B. Feral, K. Kershaw, B. Nicquevert
CERN, Geneva, Switzerland
M. Baudin
ENS, Paris, France
L. Lari
ESS, Lund, Sweden
J. Le Cardinal
École Centrale/Supélec, Chatenay Malabry, France

Particle accelerator projects share many characteristics with industrial projects. However, experience has shown that best practice of industrial project management is not always well suited to particle accelerator projects. Major differences include the number and complexity of technologies involved, the importance of collaborative work, development phases that can last more than a decade, and the importance of telerobotics and remote handling to address future preventive and corrective maintenance requirements due to induced radioactivity, to cite just a few. The openSE framework was developed as part of the PURESAFE ITN project funded by the European Commission; it is a systems engineering and project management framework specifically designed for scientific facilities' systems and equipment studies and development projects. Best practices in project management, in systems and requirements engineering, in telerobotics and remote handling and in radiation safety management were used as sources of inspiration, together with analysis of current practices surveyed at CERN, GSI and ESS.

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WEPMW002

A CLIC Damping Wiggler Prototype at ANKA: Commissioning and Preparations for a Beam Dynamics Experimental Program

wiggler, damping, storage-ring, simulation

2412

A. Bernhard, S. Casalbuoni, S. Gerstl, J. Gethmann, A.W. Grau, E. Huttel, A.-S. Müller, D. Saez de Jauregui, N.J. Smale
KIT, Karlsruhe, Germany
A.V. Bragin, S.V. Khrushchev, N.A. Mezentsev, V.A. Shkaruba, V.M. Tsukanov, K. Zolotarev
BINP SB RAS, Novosibirsk, Russia
P. Ferracin, L. Garcia Fajardo, Y. Papaphilippou, H. Schmickler, D. Schoerling, P. Zisopoulos
CERN, Geneva, Switzerland

Funding: This work is partially funded by the German Federal Ministry of Education and Research under grant 05K12VK1
In a collaboration between CERN, BINP and KIT a prototype of a superconducting damping wiggler for the CLIC damping rings has been installed at the ANKA synchrotron light source. On the one hand, the foreseen experimental program aims at validating the technical design of the wiggler, particularly the conduction cooling concept applied in its cryostat design, in a long-term study. On the other hand, the wiggler's influence on the beam dynamics particularly in the presence of collective effects is planned to be investigated. ANKA's low-alpha short-bunch operation mode will serve as a model system for these studies on collective effects. To simulate these effects and to make verifiable predictions an accurate model of the ANKA storage ring in low-alpha mode, including the insertion devices is under parallel development. This contribution reports on the first operational experience with the CLIC damping wiggler prototype in the ANKA storage ring and steps towards the planned advanced experimental program with this device.

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WEPMW008

Possible Beam Parameters in Double RF Operation of the CERN LHC

emittance, damping, synchrotron, SRF

2430

E.N. Shaposhnikova, J. F. Esteban Müller
CERN, Geneva, Switzerland

The LHC operates using a 400 MHz SC RF system. A 200 MHz NC RF system was foreseen in the LHC Design Report to improve beam capture and the bare resonators were manufactured, but never installed. Later the second harmonic RF system was proposed to cure longitudinal beam instabilities in the absence of a dedicated wideband feedback system in the LHC. For nominal intensities the longitudinal beam stability is ensured by controlled emittance blow-up during the acceleration ramp. Recently slow growing instabilities were observed at the end of long fills at 6.5 TeV as bunches shrink due to synchrotron radiation damping. For High Luminosity LHC twice higher intensities should be kept stable with new equipment installed in the ring. Additional motivations for a second RF system in the LHC have also been considered. Operation with an extra RF system is limited by the required RF configuration (phase between the two RF systems) and longitudinal beam stability. In this work requirements for the double RF systems are analyzed together with a possible range of longitudinal beam parameters.

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WEPMY033

Intermediate Commissioning Results of the 70 mA/50 keV H⁺ and 140 mA/100 keV D⁺ ECR Injector of IFMIF/LIPAC

emittance, rfq, focusing, solenoid

2625

B. Bolzon, N. Chauvin, S. Chel, R. Gobin, F. Harrault, F. Senée, M. Valette
CEA/DSM/IRFU, France
J.M. Ayala, J. Knaster, A. Marqueta, K. Nishiyama, Y. Okumura, M. Perez, G. Pruneri, F. Scantamburlo
IFMIF/EVEDA, Rokkasho, Japan
P.-Y. Beauvais, H. Dzitko, D. Gex, G. Phillips
F4E, Germany
L. Bellan
Univ. degli Studi di Padova, Padova, Italy
L. Bellan, M. Comunian, E. Fagotti, F. Grespan, A. Pisent
INFN/LNL, Legnaro (PD), Italy
P. Cara, R. Heidinger
Fusion for Energy, Garching, Germany
R. Ichimiya, A. Ihara, Y. Ikeda, A. Kasugai, T. Kikuchi, T. Kitano, M. Komata, K. Kondo, S. Maebara, S. O'hira, M. Sugimoto, H. Takahashi, H. Usami
JAEA, Aomori, Japan
K. Sakamoto
QST, Aomori, Japan
K. Shinto
Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan

The LIPAc accelerator aims to operate 125 mA/CW deuteron beam at 9 MeV to validate IFMIF's accelerators that will operate in CW 125 mA at 40 MeV. The different subsystems of LIPAc have been designed and constructed mainly by European labs and are being installed and commissioned in Rokkasho Fusion Center. The 2.45 GHz ECR injector developed by CEA-Saclay is designed to deliver 140 mA/100 keV CW D⁺ beam with 99% gas fraction ratio. Its LEBT presents a dual solenoid focusing system to transport and match the beam into the RFQ. Its commissioning continues in 2016 in parallel with the RFQ installation. The normalized RMS emittance at the RFQ injection cone is to be within 0.25π mm·mrad to allow 96% transmission through the 9.81 m long RFQ. In order to avoid activation during commissioning, an equal perveance H⁺ beam of half current and half energy as nominal with deuterons is used. In this article, the commissioning results with 110 mA/100 keV D⁺ beam and 55 mA/50 keV H⁺ beam are first reported.

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WEPOR004

Fast Orbit Feedback System at the Pls-Ii Storage Ring

feedback, electron, storage-ring, timing

2667

S.-C. Kim, W.S. Cho, C. Kim, J.M. Kim, K.R. Kim, E.H. Lee, J. Lee, J.W. Lee, T.-Y. Lee, C.D. Park, G.S. Park, S. Shin, J.C. Yoon
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This work is supported by the Ministry of science, ICT and Future Planning, Korea.
The transverse position of the electron beam in the Pohang Light Source-II (PLS-II) is stabilized by the global orbit feedback system. Currently, 2 Hz slow orbit feedback (SOFB) system is operating, and 1 kHz fast orbit feedback (FOFB) system is installed recently. This FOFB system is consists of 96 electron beam position monitors (BPMs), 48 horizontal fast correctors, 48 vertical fast correctors and VME control system. We present the design and implementation of the FOFB system and its test result. Analysis through the simulation is presented and future improvement is discussed

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WEPOR007

Recent Improvements in Drive Beam Stability in CTF3

feedback, klystron, gun, linac

2677

L. Malina, R. Corsini, D. Gamba, T. Persson, P.K. Skowroński
CERN, Geneva, Switzerland

The proposed Compact Linear Collider (CLIC) uses a high intensity, low energy drive beam producing the RF power to accelerate the low intensity main beam with 100 MeV/m gradient. This scheme puts stringent requirements on drive beam stability in terms of phase, energy and current. Finding and understanding the sources of jitter plays a key role in their mitigation. In this paper, we report on the recent studies in the CLIC Test Facility (CTF3). New jitter and drift sources were identified and adequate beam-based feed-backs were implemented and commissioned. Finally, we present the resulting improvement of drive beam stability.

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WEPOR010

Recent Upgrades to the CERN SPS Wideband Intra-bunch Transverse Feedback Processor

feedback, controls, FPGA, timing

2687

J.E. Dusatko, J.D. Fox, C.H. Rivetta
SLAC, Menlo Park, California, USA
W. Höfle
CERN, Geneva, Switzerland
O. Turgut
Stanford University, Stanford, California, USA

In support of the CERN High Luminosity LHC (HL-LHC) upgrade program, a research and development effort has been underway to understand and develop feedback control techniques for mitigating transverse intra-bunch instabilities in the SPS driven by electron cloud and TMCI effects. These effects could be a limiting factor to overall machine performance. A result of this effort has been the development of a very wide band transverse feedback demonstration system. This system has been used for the last several years in machine development studies where we have demonstrated single-bunch stability control of low order intra-bunch modes. In continuation of these efforts, recent upgrades have been performed in all stages of the system, including the feedback processor itself. This paper discusses the upgrades specific to it, including the ability to process multiple proton bunches in the SPS; and also highlights future directions in the development effort.

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WEPOR020

Beam Loss Estimation by Measurement of Secondarily Produced Photons under High Average-current Operations of Compact ERL in KEK

detector, neutron, electron, recirculation

2711

H. Matsumura, K. Haga, K. Hozumi, T. Miura, S. Nagaguro, T. Obina, T. Oyama, S. Sakanaka, A. Toyoda
KEK, Ibaraki, Japan
N. Yoshihara
Tokyo Nuclear Service Co. Ltd., Ibaraki, Japan

To increase the beam current in the Compact Energy Recovery Linac (cERL) at the High Energy Accelerator Research Organization (KEK), the beam loss must be reduced to less than 0.01% during the transportation of 20 MeV electrons in order to suppress the radiation dose outside the accelerator room. Beam loss locations were successfully identified using the gold activation method, and the beam loss rate was estimated by com-paring the measured dose rate with the simulated dose rate on the roof of the cERL room. Beam operation with beam current of 0.90 mA was achieved with a beam loss rate of less than 0.01%.

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WEPOR029

Concept of a Fire and Gas Safety System for Accelerators

interface, radiation, detector, cryogenics

2729

M. Dole, S. Grau, D. Raffourt
CERN, Geneva, Switzerland

Today CERN's facilities are equipped with automatic smoke and gas detection systems. Upon smoke or gas leak detection, local safety actions are automatically performed and alarms indicating the location and type of danger are transmitted to the CERN Fire Brigade. The firefighters then size their intervention based on the information received. The increasing complexity, size and quantity of CERN installations drives safety systems to evolve in the direction of simplicity. Intuitive interfaces are required to cope with high turnover of firefighters, and the inherent multinational environment. Global overview of alarms and safety actions statuses are needed by firefighters to decide on the best strategy for intervention. In some emergency situations, it might be necessary to manually trigger remote actions. CERN is studying a new concept, inspired by French standards, where the detection and protection layers are separated and act independently, but provide a common interface. This paper presents an application of this concept for the SPS* accelerator. Detection, fire-compartment and evacuation zones are presented, as well as the architecture of the detection and protection layers.
*SPS: Super Proton Synchrotron

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WEPOR035

MicroTCA.4-Based LLRF System for Spoke Cavities of C-ADS Injector I

LLRF, cavity, controls, cryomodule

2749

X. Ma, N. Gan, X. Huang, N. Liu, R.L. Liu, G.W. Wang, Q.Y. Wang
IHEP, Beijing, People's Republic of China
H.Y. Lin
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

The C-ADS Injector I is being built in IHEP, which includes 14 β=0.12 superconducting single spoke cavities enclosed with two cryomodules under 2 K. The MicroTCA.4-based Low Level RF (LLRF) system provides GDR mode for the operation of the cavities. The LLRF system supports both CW and duty-adjustable pulsed operation modes for the high power source and the cavities. The firmware of the FPGA controller and the EPICS IOC software has been upgraded during the last half year adding feedforward and abnormal detection. The operator interface (OPI) software and automatic operation script are also described. The MicroTCA.4 platform runs well for the beam commissioning of the Injector I. Some gained experiences with stable beam operation are also shown.

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WEPOR036

Design and Commissioning of LLRF System for ADS Project in China

LLRF, controls, cavity, proton

2752

R.L. Liu, Y.L. Chi, N. Gan, X. Huang, N. Liu, X. Ma, Z.H. Mi, G.W. Wang, Q.Y. Wang, S.Z. Wang, Z.S. Zhou
IHEP, Beijing, People's Republic of China
H.Y. Lin
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

This article describes a low-level RF control system for the ADS project at IHEP, which includes control units for an RFQ, 2 Bunchers and 14 spoke superconducting cavities with the reference line distribution. The paper covers system design consideration and implementation for those units. we will also presented some experience and results for the last one year operation of these LLRF systems.

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WEPOR040

LLRF Development for PAL-XFEL

LLRF, klystron, electron, feedback

2761

J. Hu, W.H. Hwang, H.-S. Kang, H.-S. Lee, C.-K. Min, G. Mun
PAL, Pohang, Kyungbuk, Republic of Korea
J.H. Chang, J.S. Han, Y.S. Kim
RFPT, Gyeonggi-do, Republic of Korea
O.J. Kim, H.S. Lee
Mobiis Co., Ltd., Seoul, Republic of Korea

PAL-XFEL construction is completed. Now, beam commissioning is ongoing after RF conditioning. The LLRF and SSA systems installed and in normal operation are presented. Those structures, features, characteristics, and performances are described.

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WEPOW008

Specific Operation Modes at the Metrology Light Source

electron, emittance, radiation, cavity

2829

J. Feikes, P. Goslawski, J. Li, M. Ries, M. Ruprecht, G. Wüstefeld
HZB, Berlin, Germany
A. Hoehl
PTB, Berlin, Germany

The high flexibility of the Metrology Light Source (MLS) allows application of various nonstandard user modes adapted to the specific needs of their users. We report on some of them including a mode for division of the revolution frequency for the user signal and a mode with an adjustable photon pulse delay on the few ps scale.

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WEPOW009

The Bessy Vsr Project for Short X-Ray Pulse Production

optics, storage-ring, radiation, SRF

2833

A. Jankowiak, W. Anders, T. Atkinson, H. Ehmler, A. Föhlisch, P. Goslawski, K. Holldack, J. Knobloch, P. Kuske, D. Malyutin, A.N. Matveenko, R. Müller, A. Neumann, K. Ott, M. Ries, M. Ruprecht, A. Schälicke, A.V. Vélez, G. Wüstefeld
HZB, Berlin, Germany
A. Burrill
SLAC, Menlo Park, California, USA

Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of the Helmholtz Association
HZB has started the innovative project, BESSY VSR, to upgrade the 1.7 GeV synchrotron radiation source BESSY II. Its goal is to provide both 1.7 ps and 15 ps long, intense X-ray pulses simultaneously at all beam lines. These pulses are generated by enhanced longitudinal bunch focusing using superconducting 5-cell cavities operating at 1.5 GHz and 1.75 GHz. The resulting beating of the voltages creates alternating long and short buckets that can be custom filled. As a first major step, prototype superconducting cavities, initially only cooled to 4.4 K and thus operating at reduced voltage, will be installed into the BESSY II storage ring. Physical and technical aspects of this proposal where recently studied* and the results and project status are presented.
* A. Jankowiak, J. Knobloch for the BESSY VSR team, Technical Design Study BESSY VSR, doi:10.5442/R0001, Helmholtz-Zentrum Berlin (Germany), June 2015.

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WEPOW010

Beam Lifetime Optimization by Adjusting the Sextupoles at the MLS and BESSY

sextupole, emittance, storage-ring, radiation

2837

J. Li, J. Feikes, P. Goslawski, M. Ries, M. Ruprecht, T. Tydecks
HZB, Berlin, Germany

The Metrology Light Source (MLS) is a dedicated elec-tron storage ring for metrology applications with three families of sextupoles. The existing setting of the three independently powered sextupole families respective to lifetime were roughly determined by scanning their strengths against each other. As a flexible machine the sextupole families of the MLS can be regrouped into new families, which increase the complexity of the scan pro-cedure. Consequently the former strategy would be too time-consuming for refined global scan and it has to be complemented with physical constraints. Therefore a scheme has been developed to keep the chromaticity in a reasonable range during the scan and to reduce the degree of freedom, which is even more important at BESSY II with increasing number of independent sextupole cir-cuits. This paper presents the principle of sextupole scan and the experimental results at the MLS and preliminary test at BESSY II.

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WEPOW011

BESSY II Supports an Extensive Suite of Timing Experiments

experiment, synchrotron, timing, photon

2840

R. Müller, T. Birke, F. Falkenstern, K. Holldack, P. Kuske, A. Schälicke, D. Schüler
HZB, Berlin, Germany
H.G. Glass, R. Ovsyannikov
BESSY GmbH, Berlin, Germany

The synchrotron light source facility BESSY II has put top-up and a fast orbit feedback (FOFB) into operation in 2013. Both operational improvements have matured and turned out to be especially beneficial for the advanced timing opportunities supported at BESSY. In combination with very tight injection efficiency requirements a thorough understanding of top-up injections under all operational conditions has been developed. Consequently arbitrary bunch currents can be dialed in and maintained on demand. In standard mode, a very pure camshaft bunch is available both in general for laser pump/X-ray probe and for pseudo single bunch experiments at the MHz chopper beamline. 3 constant high current bunches support the FEMTOSPEX slicing facility. An additional bunch can be resonantly excited and pulse picked via custom orbit bumps at 3 different undulator beamlines (PPRE). Due to the FOFB the classical timing modes "single bunch" and "low alpha" feature an attractive pointing stability.

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WEPOW012

Hardware Upgrades Improve the Reliability at BESSY II

storage-ring, cavity, HOM, klystron

2844

A. Schälicke, W. Anders, J. Borninkhof, V. Dürr, P. Goslawski, A. Hellwig, A. Heugel, H.-G. Hoberg, H. Hoffmann, A. Jankowiak, J. Kolbe, P. Kuske, G. Mielczarek, R. Müller, D. Pflückhahn, M. Ries, S. Rotterdam, M. Ruprecht, B. Schriefer, D. Simmering, H. Stein
HZB, Berlin, Germany

The synchrotron light source BESSY II is now in its second decade of operation. Already in 2013 both top-up and fast orbit feedback have been introduced into user operation. Currently, the facility is undergoing significant hardware upgrades in order to fulfill the increasing demands of its user community in terms of reliability, stability and flexibility. These include replacement of the DORIS cavities with EU HOM damped cavities, the upgrade of the RF transmitters to solid state amplifiers, implementation of the shifted waist optics for the new in-vacuum undulator, and refurbishment of the superconducting multi-pole wiggler. In this contribution status of BESSY II operation and the upgrade projects is reported.

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WEPOW018

Elettra Status and Upgrades

emittance, insertion, insertion-device, wiggler

2864

E. Karantzoulis, A. Carniel, S. Krecic, C. P. Pasotti
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 the possible future upgrades especially concerning the next ultra low emittance light source Elettra2.0.

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WEPOW019

SPring-8 Upgrade Project

undulator, emittance, laser, radiation

2867

H. Tanaka, T. Ishikawa
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
S. Goto, S. Takano, T. Watanabe, M. Yabashi
JASRI/SPring-8, Hyogo, Japan

Plans are underway for the upgrade of the SPring-8 facility, targeting completion in the early 2020's. Sustainability is a key guiding principle for the fourth-generation X-ray source - a beam emittance of around 100 pm.rad is pursued simultaneously with substantial energy-saving. The three key features of the design are (i) to replace the main dipole electric magnets with permanent magnets, (ii) to reduce the electron beam energy from 8 to 6 GeV, and (iii) to use the SACLA linac as an injector. Lowering the beam energy leads to reduction of (a) beam emittance, (b) magnetic fields, (c) the lengths of ID straight sections to maintain larger spaces for the magnets, and (d) the RF power consumption. Timeshare use of the SACLA linac enables beam injection to the upgraded ring with a low-emittance and short-pulsed beam as well as a reduction of injector power consumption by stopping the present injector consisting of a 1-GeV linac and a booster synchrotron. The outline of the upgrade plan will be reported with the current status of R&D started in 2015.

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WEPOW020

Present Status of KEK Photon Factory and Future Project

emittance, undulator, lattice, storage-ring

2871

T. Honda, M. Adachi, S. Asaoka, K. Haga, K. Harada, Y. Honda, X.J. Jin, T. Kageyama, R. Kato, Y. Kobayashi, K. Marutsuka, T. Miyajima, H. Miyauchi, S. Nagahashi, N. Nakamura, K.N. Nigorikawa, T. Nogami, T. Obina, M. Ono, T. Ozaki, H. Sagehashi, H. Sakai, S. Sakanaka, H. Sasaki, Y. Sato, M. Shimada, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, O. Tanaka, Y. Tanimoto, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, N. Yamamoto, Ma. Yoshida, S.I. Yoshimoto
KEK, Ibaraki, Japan

Two synchrotron radiation sources of KEK, the PF-ring and the PF-AR, continue their user operation with various improvements. Scrap and build of the first generation undulators of 1980s at the PF-ring is pushed forward year by year. Five new elliptically polarized undulators have been installed in these five years, and we have also installed four very narrow-gap short-period undulators generating high brilliant X-ray. The new beam transport line that enables the 6.5-GeV full energy injection for PF-AR will be completed by the end of 2016 in order to make the top-up operation of the two SR sources compatible with the continuous injection for two main rings of the Super-KEKB. We have proposed a project of further upgrade of the 2.5-GeV PF-ring to improve its horizontal emittance as 8 nm rad using combined bending magnets at the arc sections. And we are also moving ahead on proposal of constructing a new KEK light source of an extremely low emittance as 0.3 nm rad. The progress and detail of our future project will be described in this paper.

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WEPOW047

A Hybrid Superconducting/Normal Conducting RF System for the Diamond Light Source Storage Ring

cavity, storage-ring, vacuum, HOM

2950

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

300 mA beam in the Diamond Light Source storage ring is presently maintained by two 500 MHz superconducting CESR-B cavities. Cavity reliability is acceptable at modest operating voltages up to 1.4 MV per cavity but falls off rapidly beyond this value. The installation of an extra cavity or cavities would reduce the voltage demand on the current superconducting cavities and also the operating power level of the high power amplifiers, with commensurate improvement in machine reliability. Furthermore, two superconducting cavity failures in recent years have resulted in machine down-time and reduced-current operation and repair has proven to be prolonged and expensive. It is therefore planned to install two normal conducting cavities into the ring to support operation of the superconducting cavities and to act as a safeguard against any future superconducting cavity failures. Details are presented in this paper of plans and progress towards the installation of the hybrid RF system.

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WEPOW053

CESR Lattice for Two Beam Operations with Narrow Gap Undulators at CHESS

undulator, lattice, injection, simulation

2968

S. Wang, D. L. Rubin, J.P. Shanks
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work was supported by NSF DMR-0936384 and NSF DMR-1332208.
CESR has operated as a dedicated light source since the conclusion of colliding beam program in 2008. Two undulators with a 6.5mm-vertical gap were installed in Fall 2014, replacing a wiggler in the sextant of CESR that is the home to all CHESS beam lines. In order to operate narrow gap undulators with two beams, CESR pretzel lattice was redesigned so that e^- and e⁺ orbits are coincident in one machine sextant but separated in return arcs. In particular both e^- and e⁺ orbits are on axis through undulators. This "arc-pretzel" lattice has been the basis for undulator operation. To better understand the beam dynamics and improve machine performance, we developed many simulation tools: undulator modeling, injection tracking, etc. With installation of an additional quadrupole near undulators, the CESR lattice will be further modified with a low beta waist in the insertion devices, allowing a more than two fold reduction of local beta functions. This reduction is anticipated to mitigate the effects of small aperture and undulator field errors and to enhance the xray brightness. The characterization of the lattice will be compared with measurements of injection efficiency, tune scans, etc.

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WEPOW056

Reproducibility of Orbit and Lattice at NSLS-II

lattice, quadrupole, optics, storage-ring

2976

J. Choi, T.V. Shaftan
BNL, Upton, Long Island, New York, USA

Funding: DOE contract No: DE-SC0012704
In operating a high-end synchrotron light source, like NSLS-II, it is important to understand the machine accurately and have the ability to reproduce the desired machine state when needed. The obstacles, we can imagine, include the magnet hysteresis effect and some environmental effects. To minimize hysteresis effect, we cycle the magnets and it was proved working properly. On the other hand, from the point of long-term operation, we are not yet satisfied with the reproducibilities given by the same set of magnet currents and the machine needs additional tuning processes. In this paper, the experience of NSLS-II operation and studies are presented.

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WEPOW058

Top-off Tests and Controls Optimization

injection, controls, booster, timing

2982

G.M. Wang, M.A. Davidsaver, A.A. Derbenev, R.P. Fliller, Y. Hu, T.V. Shaftan
BNL, Upton, Long Island, New York, USA

Funding: DOE No.DE-AC02- 98CH10886
The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source at Brookhaven National Laboratory. As in many other light sources, top-off injection is considered as a standard operation mode resulting in more stable beam intensity to minimize heat load variation on the beamline optics. Top off injection specifications include maintaining the stored beam current within 0.5% and the bunch to bunch charge variation within 20% bands. To make the top off commissioning smooth and efficient, a virtual machine model based on the measured beam properties was developed. The model helped to study robustness of this application operating under different conditions and optimize the input parameters. Once tested the model was transitioned to beam commissioning. To make the beam tests more efficient, the beam lifetime was controlled by adjusting RF voltage and scrapers. In this paper, we'll share the experience from the test stage to machine implementation of the top-off controls.

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WEPOW059

The NSLS-II Top Off Safety System

injection, storage-ring, radiation, controls

2985

R.P. Fliller, D. Bergman, A. Caracappa, L. Doom, G. Ganetis, Y. Hu, Y. Li, W. Louie, D. Padrazo, O. Singh, J. Tagger, G.M. Wang, Z. Xia
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Top Off operation is the desired mode of operation for 3rd generation light sources to ensure beam current stability for user experiments. However, top off operation introduces the hazard of injecting electrons into the front ends with the beamline shutters open. This hazard can be mitigated with the appropriate safety system. This past year, the NSLS-II has transitioned from decay mode to top off operation with the introduction of the Top Off Safety System (TOSS). Top Off was initially demonstrated September 22, 2015 and become standard mode of operating. In this paper we discuss the top off safety system, operation with the system, and future directions.

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WEPOW060

Top Off Algorithm Development and Commissioning at NSLS-II

injection, storage-ring, target, feedback

2988

R.P. Fliller, A.A. Derbenev, T.V. Shaftan, G.M. Wang
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Recently, NSLS-II introduced top off as the standard mode of beam delivery for the users. During top off, we are required to maintain the beam current within ±0.5% of nominal, and the bunch to bunch variation over the train less than 20% for all operating conditions. In this paper, we discuss the algorithm used for top off, simulations of various operating conditions and performance of the algorithm during operations.

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WEPOY001

First Field Integral Measurement Campaign for Air Coil

undulator, controls, power-supply, LabView

2991

Z. Zhao, B. Du, Q.K. Jia
USTC/NSRL, Hefei, Anhui, People's Republic of China
S. Karabekyan, J. Pflüger, M. Yakopov
XFEL. EU, Hamburg, Germany

For the operation of the air coils, which are needed for the undulator segments of the European x-ray free-electron laser (E-XFEL), precise conversion constants are needed to properly convert excitation current to steering strength. This paper describes the measurement of all 200 air coils, needed for this purpose using the short moving wire (MW) system. A LabView program was developed to measure the distribution of first field integral of both vertical (B_y) and horizontal (B_z) magnetic field components in the median plane of an air coil automatically. The program is an adaptation of the existing program, which was used to characterize magnetic properties of the phase shifters (PS). Before doing the measurements the new program automatically finds the centers of B_y and B_z components, which are found to match with the geometrical centers with sufficient accuracy. After the measuring procedure is complete, the results are presented as graphics output and final tables. It shows that the measurement results can fully meet the design requirements of E-XFEL. For all measurements the excitation current of the coils was set to 1 Ampere.

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WEPOY042

Open XAL Status Report 2016

linac, software, ion, site

3083

T.A. Pelaia II, C.K. Allen, A.P. Shishlo, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA
D.A. Brown
NMSU, Las Cruces, New Mexico, USA
Y.-C. Chao
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
C.P. Chu, Y. Zhang
FRIB, East Lansing, Michigan, USA
P. Gillette, P. Laurent, E. Lécorché, G. Normand
GANIL, Caen, France
E. Laface, Y.I. Levinsen, M. Muñoz
ESS, Lund, Sweden
Y. Li
IHEP, Beijing, People's Republic of China
I. List, M. Pavleski
Cosylab, Ljubljana, Slovenia
X.H. Lu
CSNS, Guangdong Province, People's Republic of China

Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC0500OR22725 with the U.S. Department of Energy.
Formed in 2010, the Open XAL accelerator physics software platform was developed through an international collaboration among several facilities to establish it as a standard for accelerator physics software. While active development continues, the project has now matured. This paper presents the current status of the project, a roadmap for continued development and an overview of the project status at each participating facility.

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WEPOY043

Plans for the European Spallation Source Beam Physics Control Software

linac, framework, software, controls

3086

Y.I. Levinsen, R. De Prisco, M. Eshraqi, E. Laface, R. Miyamoto, M. Muñoz
ESS, Lund, Sweden
I. List
Cosylab, Ljubljana, Slovenia

The commissioning and operations planning for the European Spallation Source is currently being defined. It is foreseen that the ESS will begin to deliver beam on target by mid 2019, something which is urging a well structured and thought through plan both for commissioning and operations. In this paper we will discuss the plans for beam physics operational software, priorities and software services needed during the different stages of beam commissioning.

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WEPOY051

Performance Optimization of Multi-particle Beam Dynamics Code IMPACT-Z on NVidia GPGPU

GPU, lattice, linac, diagnostics

3110

Z.Q. He, G. Shen, Y. Yamazaki
FRIB, East Lansing, Michigan, USA
X. Wang
ICER, MSU, East Lansing, USA

Funding: The work is supported by the U.S. National Science Foundation , the U.S. Department of Energy Office of Science, the Institute for Cyber-Enabled Research, MSU.
Facility for Rare Isotope Beams is designed using a multiparticle tracking code IMPACT-Z. IMPACT-Z is originally for the purpose of accelerator design, so it is precise, however, quite time consuming, therefore usually not suitable for on-line beam tuning applications. IMPACT-Z is originally boosted using Message Passing Interface (MPI) technology. For single node mode, performance of IMPACT-Z is usually bounded by CPU performance, and for multimode mode, communication between MPI processes would become bottleneck. However, new emerging High Performance Computing (HPC) technology, like general-purpose graphics processing unit (GPGPU), brings new possibility in accelerating IMPACT-Z, so that the speed of IMPACT-Z satisfies for on-line beam tuning applications. This paper presents the efforts in exploring the capability of Nvidia GPGPU and the results of speed up of IMPACT-Z.

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WEPOY055

NSLS-II Accelerator Commissioning and Transition to Operations

lattice, storage-ring, vacuum, injection

3120

T.V. Shaftan
BNL, Upton, Long Island, New York, USA

Over past year NSLS-II has completed accelerator commissioning and enabled operations of first project beam lines. Recently we further optimized the NSLS-II accelerators, increased the beam current to 400 mA without- and to 250 mA with Insertion Devices (IDs), commissioned top-off mode of operations and stabilized beam orbit to below 10% of the beam size in the source points. In this paper we report progress on the NSLS-II accelerator commissioning and operations and plans for future facility developments.

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THOAA02

The Development of C-Band Cavity Beam Position Monitor with a Position Resolution of Nano Meter

cavity, dipole, electronics, feedback

3149

S.W. Jang, E.-S. Kim
Korea University Sejong Campus, Sejong, Republic of Korea
P. Bambade, O.R. Blanco-García, S. Wallon
LAL, Orsay, France
N. Blaskovic Kraljevic, T. Bromwich, P. Burrows
JAI, Oxford, United Kingdom
T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan

We developed and tested an C-band beam position monitor with position resolution of nano meter in ATF2. The C-band BPM was developed for the fast beam feedback system at the interaction point of ATF in KEK, which C-band beam position monitor called to IPBPM (Interaction Point Beam Position Monitor). The developed IPBPM was measured 26nm with 30% of nominal beam charge of ATF. From the measured beam position resolution, we can expected to 8nm beam position resolution with nominal ATF beam charge condition. In this talk, we will described about the development of IPBPM and the beam test results of nano meter level beam position resolution.

Slides THOAA02 [4.806 MB]

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THOAA03

MicroTCA.4 based Single Cavity Regulation including Piezo Controls

cavity, controls, feedback, electron

3152

K.P. Przygoda, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany
P. Echevarria
HZB, Berlin, Germany
R. Rybaniec
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

We want to summarize the single cavity regulation with MTCA.4 electronics. Presented solution is based on the one MTCA.4 crate integrating both RF field control and piezo tuner control systems. The RF field control electronics consists of RTM for cavity probes sensing and high voltage power source driving, AMC for fast data processing and digital feedback operation. The piezo control system has been setup with high voltage RTM Piezo driver and low cost AMC based FMC carrier. The communication between both control systems is performed using low latency link over the AMC backplane with data throughput up to the 3.125 Gbps. First results from CW operation of the RF field controller and the cavity active resonance control with the piezo tuners are demonstrated and briefly discussed.

Slides THOAA03 [2.693 MB]

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THYB01

Performance of Superconducting Cavities for the European XFEL

cryomodule, cavity, SRF, vacuum

3186

D. Reschke
DESY, Hamburg, Germany

The superconducting accelerator of the European XFEL consists of the injector part and the main linac. The injector includes one 1.3 GHz accelerator module and one 3.9 GHz third harmonic module, while the main linac consists of 100 accelerator modules, each housing eight 1.3 GHz TESLA-type cavities, operated at an average design gradient of 23.6 MV/m. The fabrication and surface treatment by industry as well as the vertical and cryomodule RF tests of the required 808 superconducting 1.3GHz cavities are analysed and presented.

Slides THYB01 [3.227 MB]

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THOBB03

Root Causes of Field Emitters in SRF Cavities Placed in CEBAF Tunnel

cavity, cryomodule, SRF, vacuum

3198

R.L. Geng
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
It has been suspected that appearance of new field emitters can occur in SRF cavities after their placement in accelerator tunnel for long term beam operation. This apparently has been the case for CEBAF. However, no physical evidence has been shown in the past. In this contribution, we will report on the recent results concerning the root cause of field emitters in SRF cavities placed in CEBAF tunnel. We will discuss these results in the context of high-reliability and low-cryogenic-loss operation of CEBAF.

Slides THOBB03 [3.768 MB]

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THPMB030

Operation Improvement by Tuning of Storage Ring at PLS-II

injection, kicker, storage-ring, linac

3297

I. Hwang, M. Kim, T.-Y. Lee, C.D. Park
PAL, Pohang, Kyungbuk, Republic of Korea

After upgrade of the pohang light source (PLS-II), several problems reduced the quality of the top-up operation. Unbalance of the injection kicker system and it's lack of control had limited the efficiency of the injection from the linac to the storage ring. We tuned the storage ring to improve the injection efficiency and to stabilize the orbit during the injection.

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THPMB034

Short Bunch Operation Mode Development at the Synchrotron Radiation Source Siberia-2

optics, emittance, synchrotron, synchrotron-radiation

3305

Y.A. Fomin, V. Korchuganov, S.I. Tomin, A.G. Valentinov
NRC, Moscow, Russia

Decrease of the electron bunch length gives rise to coherent synchrotron radiation in the THz spectral region. Also, the short photons pulse could provide an option for time-resolved processes studies. Currently the possibility to operate with short electron bunch of the synchrotron radiation source Siberia-2 is under consideration for this purpose. In the report the techniques of electron bunch shortening are described as well as the requirements are given for the parameters of the electron bunch and lattice. The authors present a modified lattice for the synchrotron radiation source Siberia-2 with low momentum compaction factor and the results of the beam dynamics studies.

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THPMB036

Model-Dependent Accelerator Lattice Fit Based on BPM Data and Generating Functions

sextupole, lattice, quadrupole, alignment

3311

Yu. Maltseva, I.A. Morozov
BINP SB RAS, Novosibirsk, Russia

Obtaining accurate linear and nonlinear accelerator models is critical for routine accelerator operation. Here we consider a method based on BPM data and generating functions that provides fitted accelerator model. Using measurements from at least three BPMs and generating functions between them allows obtaining momenta at BPMs as the functions of model parameters and comparing them. Thus, lattice parameters can be fitted. Theoretical results are presented and the method is applied to the model examples.

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THPMB043

Progress in Ultra-Low β* Study at ATF2

emittance, optics, linear-collider, extraction

3335

M. Patecki, D.R. Bett, F. Plassard, R. Tomás
CERN, Geneva, Switzerland
K. Kubo, S. Kuroda, T. Naito, T. Okugi, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan
M. Patecki
Warsaw University of Technology, Warsaw, Poland
T. Tauchi, N. Terunuma
Sokendai, Ibaraki, Japan

A nanometer beam size in the interaction point (IP) is required in case of future linear colliders for achieving the desired rate of particle collisions. KEK Accelerator Test Facility (ATF2), a scaled down implementation of the beam delivery system (BDS), serves for investigating the limits of electron beam focusing at the interaction point. The goal of the ultra-low beta∗ study is to lower the IP vertical beam size by lowering the beta_y∗ value while keeping the beta_x∗ value unchanged. Good control over the beam optics is therefore required. The first experience with low beta∗ optics revealed a mismatch between the optics designed in the model with respect to the beam parameters observed in the experiment. Additionally, existing methods of beam parameters characterization at the IP were biased with high uncertainties making it difficult to set the desired optics. In this paper we report on the new method introduced in ATF2 for IP beam parameters characterization which gives a good control over the applied optics and makes the ultra-low beta∗ study possible to conduct. It can be also used for verifying the performance of some of the existing beam instrumentation devices.

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THPMB046

Status and Plans for Completion of the Experimental Programme of the Clic Test Facility Ctf3

acceleration, controls, linac, emittance

3347

P.K. Skowroński, R. Corsini, S. Döbert, W. Farabolini, D. Gamba, L. Malina, T. Persson, F. Tecker
CERN, Geneva, Switzerland
W. Farabolini
CEA/DSM/IRFU, France
D. Gamba
JAI, Oxford, United Kingdom

The CLIC Test Facility CTF3 was build, commissioned and operated at CERN by an international collaboration, with the aim of validating the CLIC two beam acceleration scheme, in which the RF power used to accelerate e⁺/e⁻ beams is extracted from a high intensity electron beam. In the past years the main issues of such a scheme were assessed, demonstrating its feasibility. The CTF3 experimental programme is complementing these results by addressing cost and performance subjects, mainly using the CALIFES test beam injector and a full scale two-beam module. In this paper we document the present status and give an outlook to next year run, when the experimental programme should be completed.

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THPMB051

Development of Intelligent Alarm Message System at TPS

status, vacuum, radiation, SRF

3363

C.C. Liang, C.H. Chang, C.H. Chen, J. Chen, J.Y. Chen, Y.-S. Cheng, M.-S. Chiu, S. Fann, C.S. Huang, C.-C. Kuo, T.Y. Lee, Y.C. Lin, Y.-C. Liu, H.-J. Tsai, F.H. Tseng, I.C. Yang, T.-C. Yu
NSRRC, Hsinchu, Taiwan

The traditional alarm systems usually set up/low limit for various signals. When the acquired values exceed the limits, the alarm system would be activated. The proposed system in this article can focus on various possible events with many kinds of signals for response judgments. During alarm calling period, data can also be announced and recorded. The system can also monitor various events according to different time shifts. Integrating LabVIEW, mobile phone, AT-command and Bluetooth communication, the system can handle factory broadcast, sending E-mail and SMS message. The above sound and words messages can be set directly at the home-made software interface. The new intelligent alarm system can eliminate the procedure made by man with the added event recording, system stability improvement and debugging function in wider application fields.

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THPMR017

Resonance Island Experiments at BESSY II for User Applications

undulator, photon, resonance, experiment

3427

P. Goslawski, J. Feikes, K. Holldack, A. Jankowiak, M. Ries, M. Ruprecht, A. Schälicke, G. Wüstefeld
HZB, Berlin, Germany
R. Ovsyannikov
BESSY GmbH, Berlin, Germany

Beam storage close to a tune resonance (Qx = 1/3, 1/4) can generate resonance island buckets in the x,x' phase space providing a second stable island orbit winding around the standard orbit. Experiments with such an operation mode have been conducted at BESSY II and the Metrology Light Source (MLS)*,**. The two orbits are well separated, with good life time and stability. Such operation mode will offer additional operation flexibility and allows users to choose their radiation source point from one or the other orbit. It has the potential to fulfill simultaneously conflicting user demands, e.g., high vs. low beam current and single or few bunch filling vs. multibunch filling. We discuss the required beam optics setup and present successful measurements taken at photon beamlines at BESSY II.
* P. Goslawski et al., "Bunch Separation by Transverse Resonance Island Buckets", ESLS XXIII Workshop, 2015, Villigen, Switzerland.
** M. Ries et al., Proc. IPAC 2015, Richmond, USA, MOPWA021.

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THPMR020

Bunch Purity Measurements at PETRA III

electron, scattering, synchrotron, timing

3434

J. Keil, H. Ehrlichmann
DESY, Hamburg, Germany

Since 2010 the 6 GeV synchrotron light source PETRA III is in operation. With a horizontal emittance of 1.2 nm*rad, a coupling of typically 1% and a total beam current of 100 mA the machine provides extremely brilliant synchrotron radiation for the users. For time-resolved measurements a filling pattern with 40 equidistant bunches with equal charge is used. To measure parasitic bunches between the main bunches two beamlines are equipped with avalanche photodiodes (APD) and time to digital converters (TDC) electronics. Besides parasitic bunches originating from the pre-accelerators of PETRA III it has been observed that initially empty buckets following the main bunch are populated. Measurements of the effect will be discussed and compared with simulations.

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THPMR039

Commissioning of Non-linear Optics in the LHC at Injection Energy

injection, dipole, octupole, optics

3476

E.H. Maclean, F.S. Carlier, J.M. Coello de Portugal, A. Garcia-Tabares, A. Langner, L. Malina, T. Persson, P.K. Skowroński, R. Tomás
CERN, Geneva, Switzerland

Commissioning of the nonlinear optics at injection in the LHC was carried out for the first time in 2015 via beam-based methods. Building upon studies performed during Run I, corrections to the nonlinear chromaticity and detuning with amplitude were obtained. These corrections were observed to reduce beam-loss during measurement of linear optics.

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THPMR044

Short Term Dynamic Aperture with AC Dipoles

dipole, dynamic-aperture, resonance, simulation

3496

S. Mönig, J.M. Coello de Portugal, A. Langner, E.H. Maclean, T. Persson, R. Tomás
CERN, Geneva, Switzerland

The dynamic aperture of an accelerator is determined by its non-linear components and errors. Control of the dynamic aperture is important for a good understanding and operation of the accelerator. The AC dipole, installed in the LHC for the diagnostic of linear and non-linear optics, could serve as a tool for the determination of the dynamic aperture. However, since the AC dipole itself modifies the non-linear dynamics, the dynamic aperture with and without AC dipole are expected to differ. This paper will report the results of studies of the effect of the AC dipole on the dynamic aperture.

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THPMW001

SuperKEKB Main Ring Power Supply System

power-supply, wiggler, quadrupole, controls

3531

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

The power supplies for magnets of KEKB main ring were recycled into SuperKEKB main ring. Several tests were performed for all of the power supplies to check the soundness. Some of the power supplies were improved to satisfy the requirements of optical design, and some of them were replaced by new power supplies. Most of the trim-coils were arranged with one of power supply per a coil in SuperKEKB. The total number of the power supplies is over 2000.

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THPMW010

PAL-XFEL Dipole Magnet Power Supplies

dipole, controls, quadrupole, power-supply

3555

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

Total 632 magnet power supplies (MPSs) are under operating in PAL-XFEL. These magnet power supplies can be categorized as three types - corrector, quadrupole and dipole. The dipole MPSs are ranging from 110A/80V bipolar PS to 310A/200V unipolar PS. The long term stability of bipolar power supply is 10 ppm with 250 A 40V output for gun solenoid. The three types of dipole MPSs are developed for PAL-XFEL. Precise measurement results show that all power supplies meet the required specifications. The long term operation stability of the MPSs are appeared to be sufficient for a stable operation of the PAL-XFEL.

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THPMW011

Magnet Power Supplies Performance at the PLS-II Storage Ring

sextupole, quadrupole, storage-ring, power-supply

3558

S.-C. Kim, A. Ahn, J.M. Kim, K.R. Kim, C.D. Park, J.C. Yoon
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This work is supported by the Ministry of science, ICT and Future Planning, Korea.
Magnet power supplies(MPS) are operating unipolar(bending, main-quadrupole, sextupole and septum) and bipolar(slow corrector, fast corrector, aux-quadrupole and skew) at the PLS-II storage ring(SR). Unipolar MPSs maintain stability, and bipolar MPSs maintain stability, have best resolution performance total operation region including zero-crossing during beam operation. Slow and fast corrector MPSs for beam correction have good step response characteristics. In this paper, we present the improve activity and performance of the PLS-II SR MPS.

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THPMW012

The Fast Interlock Controller for High Power Pulse Modulator at PAL-XFEL

PLC, controls, interlocks, vacuum

3561

S.H. Kim, H.-S. Kang, K.H. Kim, S.J. Kwon, H.-S. Lee, S.S. Park, Y.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea
I.S. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: This work is supported by Ministry of Science, ICT(Information/Communication Technology) and Future Planning.
The modulator control system for PAL-XFEL consists of a PLC unit (Programmable Logic Controller) and FPSCM (Fast Pulse Signal Conditioning Module). There are two kinds of interlock, which are dynamic and static interlocks categorized as analogue monitor and control signals, digital monitor and control signals. In case of dynamic interlocks, the internal interface of the PLC unit had to be modified due to operating within 10 ms time response from the interlock event. The fast pulse signal conditioning module is adopted for preconditioning the fast pulse and DC signals that inherently have high noise levels generated from a beam voltage, a beam current and EOLC current. Those EM (Electro-Magnetic) noises are generated by thyratron switching. The amplitude of the thyratron noise is large which causes the problem at the control devices, frequently. In this paper, the test results of the interlock control system will be described.

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THPMW013

Development of PAL-XFEL Magnet Power Supply

interface, FPGA, power-supply, status

3564

K.-H. Park, S.-H. Jeong, Y.-G. Jung, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, B.G. Oh, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea
W.S. Choi
POSTECH, Pohang, Kyungbuk, Republic of Korea

All magnets and magnet power supplies (MPS) for PAL-XFEL had been installed at the site. The all MPSs had been tested with the magnets at the field. The total number of assembled MPSs was amounted to 688, which were grouped into nine categories by their power capacities in order to reduce the manufacturing cost and make maintenance easy. The general specifications for the MPS for the PAL- XFEL were summarized. The design configurations of the MPS were also explained to satisfy the given requirements such as the output current stability. The test results of performances of the MPSs for corrector magnets were described here.

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THPMW014

High Voltage Supply for Particle Accelerators Based on Modular Multilevel Converters

high-voltage, power-supply, flattop, controls

3567

P. Asimakopoulos, K.D. Papastergiou
CERN, Geneva, Switzerland

Modular Multilevel Converters brought a paradigm shift in very high voltage and high power applications with the replacement of high voltage valves by multiple series-connected, low-voltage modules that can be by-passed in case of fault. The reliability and precision in output waveform generation make it a potential candidate in accelerator power conversion. This work demonstrates operation of MMC-based high voltage magnet supply for a transfer line application. The output current regulation precision and the total power losses are examined. Finally, the challenge of the control optimization combined with the passive components dimensioning is highlighted.
* R. Marquardt and A. Lesnicar, "An innovative modular multilevel converter topology suitable for a wide power range", in Proc. IEEE Bologna Power Technol. Conf., Jun. 2003, pp. 1-6.

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THPMW018

Simulation a High Step-up DC-DC Converter for Accelerator

simulation, power-supply, sextupole, quadrupole

3579

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

This paper simulation a novel high step-up DC-DC high circuit architecture for storage ring quadrupole and sextupole power supply DC bus voltage. The input source is a low voltage photovoltaic energy through proposed circuit to increase high output voltage system. This volt-age can be as DC bus of quadrupole and sextupole power supply. The part of the circuit has a power switch, isolated transformer inductors, switched capacitors and diodes. This proposed circuit has the advantages of galvanic isolation function, small transformer and high step-up gain and efficiency. Continuous conduction mode (CCM) operation principles are discussed in this paper. Finally, Simplis software has been used for simulation a 24 Vdc step-up to 200 Vdc and 100 w DC-DC converters.
high step-up, switched capacitor, photovoltaic

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THPMW019

Concept and Design of the Injection Kicker System for the FAIR SIS100 Synchrotron

vacuum, kicker, ion, pulsed-power

3582

I.J. Petzenhauser, U. Blell, P.J. Spiller
GSI, Darmstadt, Germany
L.O. Baandrup, H. Bach, N. Hauge, K.F. Laurberg
Danfysik A/S, Taastrup, Denmark
G. Blokesch, M. Osemann
Ampegon PPT GmbH, Dortmund, Germany

The SIS100 synchrotron at GSI, Germany is designed for acceleration of protons and ions. For the injection into the synchrotron a kicker magnet system, which consists of 6 ferrite kicker magnet modules, installed in one vacuum tank with a required vacuum quality better than 10-9 Pa, will be needed. The magnetic field should be 118 mT in a 65 mm gap. These kicker magnet modules will be supplied with 6 separate pulser circuits. Each pulser has to produce a pulse current of up to 7 kA at a PFL (pulse forming line) voltage of 80kV at an impedance of 5.7 Ohm. The rise time has to be 130 ns and the variable pulse length is between 0.5 to 2.0 μs. The design concept for this kicker system from Ampegon PPT and DANFYSIK and the specific challenges will be described.

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THPMW020

Solid-state Compact Kicker Pulsar using Strip-line Type Blumlein with SIC-MOSFET in Spring-8

high-voltage, impedance, kicker, storage-ring

3585

C. Mitsuda, T. Honiden, K. Kobayashi, T. Kobayashi, S. Sasaki
JASRI/SPring-8, Hyogo-ken, Japan
N. Sekine
Sekine Electric Works Co. Ltd, Osaka, Japan

In the case of handling the electron beam by bunch-by-bunch and turn-by-turn with a kicker at the SPring-8, the performances required to a pulsar are short pulse width (<40ns) and high repetitions (>208kHz). In order to achieve these specifications, the short pulsed high voltage output and the utilization of the solid-state switch is necessary for an inductance load. In order to suppress the supplied voltage as low as as possible, it is an important feature to realize the extremely small-sized pulsar to be set near the kicker. On the basis of the experiences in developing the solid-state pulsar of 400ns/2kV using Si-MOSFET*, combination of the SiC-MOSFET and the strip-line type Blumlein pulse forming network (BPFN) was applied to the prototype driver to achieve a shorter pulse and higher power than Si-type driver. The completed pulsar accomplished a compact size (external dimensions; 300(H)x400(W)x400(D)mm). Furthermore, the targeted short-pulsed high voltage output of 123ns/12kV was obtained by 6 BPFNs serial connection to the load inductance of 800 nH. The BPFN detailed design to enable the compact size, high reliability and stability at high repetitions will be reported.
* C.Mitsuda et al., Proc. of IPAC2013, MOPAWA003

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THPMW027

Development of a Long Pulse High Power Klystron Modulator for the ESS Linac based on the Stacked Multi-level Topology

klystron, high-voltage, linac, DTL

3600

C.A. Martins
ESS, Lund, Sweden
M. Collins, A. Reinap
Lund Technical University, Lund, Sweden

A novel Stacked Multi-Level modulator topology optimized for long pulse and high average power applications has been developed at ESS. It utilizes six identical modules connected in series at the HV output side and fed in parallel from the low voltage side. Each one is formed by one HF inverter, one step-up transformer, one HV rectifier bridge and one HV passive filter. They are supplied in groups of two from three capacitor banks which in turn will be charged from the low voltage electrical grid by using three groups of active AC/DC and DC/DC converters. Industrial standard power electronic components are used at the primary stage, which are placed in conventional electrical cabinets. Only few special components (transformers, rectifiers, filters) are required to be placed in an oil tank. A technology demonstrator rated for 115kV/20A and 3.5ms/14Hz is at the final phase of construction. The main power conversion circuit and regulation principles will be described and details on the design and construction of the main sub-systems will be given. Simulation and experimental results will be given showing the achieved performance in terms of HV pulse quality and AC grid power quality

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THPMW033

Operational Experience of the Upgraded LHC Injection Kicker Magnets

kicker, injection, vacuum, impedance

3623

M.J. Barnes, A. Adraktas, G. Bregliozzi, S. Calatroni, H.A. Day, L. Ducimetière, B. Goddard, V. Gomes Namora, V. Mertens, B. Salvant, J.A. Uythoven, L. Vega Cid, W.J.M. Weterings, C. Yin Vallgren
CERN, Geneva, Switzerland

During Run 1 of the LHC the injection kicker magnets caused occasional operational delays due to beam induced heating with high bunch intensity and short bunch lengths. In addition, sometimes there were also sporadic issues with microscopic unidentified falling objects, vacuum activity and electrical flashover of the injection kickers. An extensive program of studies was launched and significant upgrades were carried out during long shutdown 1. These upgrades include a new design of a beam screen to both reduce the beam coupling impedance of the kicker magnet, and to significantly reduce the electric field associated with the screen conductors, hence decreasing the probability of electrical breakdown in this region. In addition new cleaning procedures were implemented and equipment adjacent to the injection kickers and various vacuum components were modified. This paper presents operational experience of the injection kicker magnets during Run 2 of the LHC and assesses the effectiveness of the various upgrades.

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THPMW035

Considerations on an Upgrade Possibility of the LHC Beam Dump Kicker System

kicker, extraction, quadrupole, optics

3631

M.A. Fraser, W. Bartmann, C. Bracco, L. Ducimetière, B. Goddard, T. Kramer, V. Senaj
CERN, Geneva, Switzerland

The LHC Beam Dump System (LBDS) is designed to safely dispose the circulating beams over a wide range of energy from 450 GeV up to 7 TeV, where the maximum stored energy is 362 MJ per beam. One of the most critical components of the LBDS are the extraction kickers that must reliably switch on within the 3 us particle-free abort gap. To ensure this functionality, even in the event of a power-cut, the power generator capacitors remain charged and hence the Gate Turn-Off (GTO) switch stack has to hold the full voltage throughout beam operation. The increase of the LHC collision energy to 13 TeV has increased the voltage levels at the GTO stacks and during re-commissioning an increased rate of high-voltage (HV) related issues at the level of the GTO stack was observed. Different solutions have been analysed and an improved GTO stack will be implemented. This paper also outlines the benefit of adding more kicker magnets to improve the voltage hold off issues and to improve the tolerance to missing kickers during extraction.

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THPMW037

Pulsed Power Systems for ESS Klystrons

klystron, electronics, cathode, high-voltage

3634

I. Roth, M.P.J. Gaudreau, M.K. Kempkes
Diversified Technologies, Inc., Bedford, Massachusetts, USA
J. Domenge
Sigma Phi Electronics, Wissembourg, France
J.L. Lancelot
Sigmaphi, Vannes, France

Diversified Technologies, Inc. (DTI) is building three long pulse solid-state klystron transmitters to meet spallation source requirements. Two of the three will be installed at CEA Saclay and the National Institute of Nuclear and Particle Physics (IN2P3) in 2015, to be used as test stands for the European Spallation Source (ESS), The third system will be installed at Oak Ridge National Laboratory (ORNL) for the Spallation Neutron Source (SNS).

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THPMW042

Overview of Driver Technologies for Nanosecond TEM Kickers

impedance, controls, kicker, injection

3645

A.K. Krasnykh
SLAC, Menlo Park, California, USA

Funding: Work supported in part by US Department of Energy under contract DE-AC02-76SF00515 and in part by US Department of Energy under contract DE-AC02-06CH11357
Overview of modern methods, circuits, and practical realizations for multi MW peak power pulsers will be presented. All used pulser components are manufactured by the US national industry and they are available for design and pulser fabrication. Two concepts will be discussed: (1) an approach is based on assistance of a nonlinear transmission line with ferromagnetic media and (2) an approach is based on assistance of special diodes which are working in a specific mode of operation. In both approaches the nonlinear characteristic of switching media (ferromagnetic and solid state plasma) are employed in final stage of the pulser to form the multi MW level nanosecond pulses.

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THPMY006

Analysis and Testing of a New RF Bridge Concept as an Alternative to Conventional Sliding RF Fingers in LHC

vacuum, impedance, ion, alignment

3660

J. Perez Espinos, C. Garion
CERN, Geneva, Switzerland

RF fingers are used as transition elements in beam vacuum line interconnections to ensure the continuity of the vacuum system wall within acceptable beam stability requirements. The RF fingers must absorb and compensate longitudinal, angular and transversal misalignments due to both thermal effects, during bake-out or cooldown processes, and mechanical movements during assembly, alignment, commissioning and operation phases. The new RF bridge concept is based on a deformable thin-walled structure in copper beryllium, which fulfils the above requirements without the need of sliding contacts. Mechanical tests have been carried out to characterize the response and the lifetime of such a component under different loading conditions. In addition, finite element models have been used to estimate the behaviour. The influence of different material grades and heat treatments on the reliability is presented. The paper includes a detailed analysis of the prototyping and testing phases that have led to a final design of the system, qualified on a dedicated test bench, for the collimator vacuum modules of LHC.

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THPMY010

LHC Beam Vacuum Evolution During 2015 Machine Operation

electron, proton, solenoid, luminosity

3673

C. Yin Vallgren, G. Bregliozzi, P. Chiggiato
CERN, Geneva, Switzerland

The LHC successfully returned to operation in April, 2015 after almost 2 years of Long Shutdown 1 (LS1) for various upgrade and consolidation programs. During 2015 operation, the LHC operated for more than 1000 fills. The 2015 LHC proton physics ended with 2244 bunches per beam circulating with 25 ns bunch spacing at top energy of 6.5 TeV. This paper summarizes the dynamic vacuum observations in different locations along the LHC during dedicated fills as well as during physics runs with both 50 ns and 25 ns bunch spacing. The causes for the dynamic pressure rises are investigated and are presented. A clear beam conditioning effect is observed, as well as a so-called de-conditioning effect. Furthermore, for the experimental areas, the dynamic pressure evolution is also presented.

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THPMY019

LHC Injection Protection Devices, Thermo-mechanical Studies through the Design Phase

injection, kicker, proton, impedance

3698

I. Lamas Garcia, N. Biancacci, G. Bregliozzi, M. Calviani, M.I. Frankl, L. Gentini, S.S. Gilardoni, A. Lechner, A. Perillo-Marcone, B. Salvant, N.V. Shetty, J.A. Uythoven
CERN, Geneva, Switzerland

The TDI is a beam intercepting device installed on the two injection lines of the LHC. Its function is to protect the superconducting machine elements during injection in the case of a malfunction of the injection kickers. The TDIS, which will replace the TDI, is foreseen to be installed for high luminosity operation. Due to the higher bunch intensities and smaller beam emittances expected, and following the operational experiences of the TDI, a complete revision of the design of the jaws must be performed, with a main focus on the material selection. Furthermore, the new TDIS will also improve the TDI reliability by means of a robust design of the jaw positioning mechanism, the efficiency of the cooling circuit and by reducing its impedance. A simplified installation procedure and maintenance will also be an important requirement for the new design. This paper introduces the main characteristics of the TDI as LHC injection protection device, showing the needs and requirements for its upgrade. It also discusses the thermo-mechanical simulations that are supporting and guiding the design phase and the material selection, and describes the modifications to be implemented, so far, for this new device.

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THPMY022

Design of the Beam Dump for Low Flux Beamline in KOMAC

proton, radioactivity, linac, radiation

3702

C.R. Kim, Y.-S. Cho, H.S. Kim, H.-J. Kwon
Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea

Funding: This work has been supported through KOMAC (Korea Multi-purpose Accelerator Complex) operation fund of KAERI by MSIP (Ministry of Science, ICT and Future Planning)
A linac in KOMAC (Korea Multi-Purpose Accelerator Complex) is providing users with 100-MeV proton beam for various applications. A new target room (TR102) for low dose of radiation beam will be constructed in 2016. The beam dump is an important part of this beam line and must be designed to stop 100 MeV beams with a maximum power of 10 kW. Incepting the waste of beam increases the temperature of the beam dump, which can make a structural problem. Therefore, the material of it should be robust under the high temperature and the radioactive circumstance. To ensure safety, thermo-mechanical analyses have been performed for a few materials using a finite element code. The beam dump will be fabricated based on the analysis results.

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THPMY029

Technical Overview of the PAL-XFEL Low-Conductivity Water Cooling System

controls, simulation, laser, ion

3718

B.H. Lee, H.-G. Kim, K.W. Kim, K.R. Kim, S.H. Kim, Y. C. Kim, H.M. Lee, M.S. Lee, H. Matsumoto, I. Mok, C.W. Sung, J. Yang
PAL, Pohang, Kyungbuk, Republic of Korea
J.H. Jeon
Taeyoung, Seoul, Republic of Korea
K.T. Kim
HMT, Pohang, Republic of Korea
I.S. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea

Pohang Accelerator Laboratory (PAL) started operation of an X-ray Free Electron Laser (XFEL) based on 10GeV linear accelerator in FY2015. For accurate temperature control of the various XFEL accelerator devices, a low-conductivity water (LCW) cooling system were installed. The LCW pump station generates LCW controlling the temperature variation within ±0.1°C. The LCW is supplied to klystrons including modulators and various control devices. On the other hand, the precision temperature controlled water to minimize temperature variation down to ±0.02°C. This water is supplied to accelerating columns, wave guide and SLED. Therefore, this paper shows the design, construction and operation of the LCW cooling system.

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THPMY030

How to Manage a Large Scale Beam Line Consolidation in a Highly Activated Area?

radiation, controls, target, vacuum

3721

S. Evrard, J.L. Grenard, E. Harrouch, A. Herve, A. Pardons, Y. Pira, Y.D.R. Seraphin, C. Theis, H. Vincke
CERN, Geneva, Switzerland

The TDC2/TCC2 consolidation is a good example showing how the complexity of interventions in high radiation areas has increased over the last five years. Due to its duration, its dispersion, the diversity of the teams involved, the fixed deadlines, the risks and external constraints, this worksite prefigures large scale-interventions in the LHC during long shutdown 2 (LS2) and even more LS3. The paper describes the three main project phases: preparation, execution (including monitoring and control) and closure emphasizing the indispensable steps in each stage. It also explains why integrating scope, schedule and dose into a single baseline is of prime importance and shows how to manage and monitor the radiation safety performance of the various interventions throughout the execution phase. Eventually, some recommendations are formulated in order to better accommodate the design of high radiation areas to their operation and maintenance constraints.

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THPMY031

The Methods to Optimize Power Usage for Chiller System of TPS Utility

controls, factory, experiment, synchrotron

3725

C.S. Chen, W.S. Chan, J.-C. Chang, Y.C. Chang, Y.-C. Chung, C.Y. Liu, Z.-D. Tsai
NSRRC, Hsinchu, Taiwan

The recently completed Taiwan Photon Source (TPS) is one of the brightest synchrotron X-ray sources in the world. It will offer 500 mA beam current at 3 GeV for all kinds of different subject experiments and novel scientific ideas. This facility will be the most inspiring trigger to Taiwan's scientific research in the twenty-first century. In order to make sure this giant machine operate properly, the utility system plays a very important role. Not only for the giant machine, the utility system also takes responsibility for providing a cozy environment for all staff. Furthermore, the requirements of air condition in some critical areas are very strict even to ± 0.1°C temperature accuracy. All of it cost a large amount of energy to satisfy everyone's demand. According to the annual budget report of NSRRC, the total charge of electricity and water was more than 80 million N.T. dollars per year before TPS project, and increased by nearly twice after TPS inauguration. Since the government budget is limited, the whole utility system must be operated under more economic ways to use energy more efficiently.

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THPMY032

Air Conditioning System Control Study and Improvement for Transient Events in the TLS Storage Ring

controls, storage-ring, dipole, status

3728

J.-C. Chang, C.S. Chen, C.Y. Liu, Z.-D. Tsai
NSRRC, Hsinchu, Taiwan

It has been studied and verified that thermal effect is one of the most critical mechanical factors affecting the beam stability. There are many accelerators have controlled the global air temperature variation in the storage ring tunnel within ±0.1C during stable beam operation in the world. However, some transient events, such as unexpected beam loss or beam trip will clearly affect air temperature variation. Moreover, machine shutdown will change the air conditioning status radically. It will also take time to reach a stable air temperature after machine shutdown. This paper presents effects on the air temperature by those transient events and improvement schemes.

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THPMY033

Vibration Evaluation for Deionized Water Pumps in TPS

booster, coupling, alignment, status

3731

Y.-H. Liu, C.S. Chen, Y.-C. Chung
NSRRC, Hsinchu, Taiwan

The purpose of this paper is to evaluate the vibration level and spectrum for TPS deionized water pumps. The utility systems started to operate from the beginning of 2014, some of deionized water pumps produced higher vibration level and noise during operation. The possibly reason could be not appropriated installation and commission test. In order to figure out the status of these deionized water pumps, the vibration analysis become needed. After vibration test, the booster(BO) and copper(CU) deionized water pump systems generate higher vibration level. According to the vibration test results, the pump is repair and maintain. Although there is some problems for TPS deionized water pumps, the vibration test is still one important way to maintain utility systems. The utility systems could prevent malfunction through regular vibration inspection.

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THPMY034

Power Saving Status at NSRRC

controls, radiation, synchrotron, synchrotron-radiation

3734

J.-C. Chang, W.S. Chan, Y.C. Chang, C.S. Chen, Y.F. Chiu, Y.-C. Chung, K.C. Kuo, M.T. Lee, Y.-C. Lin, C.Y. Liu, Y.-H. Liu, Z.-D. Tsai, T.-S. Ueng, J.P. Wang
NSRRC, Hsinchu, Taiwan

National Synchrotron Radiation Research Center (NSRRC), Taiwan currently operates two synchrotrons, the Taiwan Light Source (TLS) and Taiwan Photon Source (TPS). The former one has been operated for more than 22 years, while the latter is in commissioning phase. We target of the beam current on 500 mA. Thus, the power consumption increases higher than ever. Currently, the contract power capacities of the TLS and TPS with the Taiwan Power Company (TPC) are 5.5MW and 7.5MW, respectively. The ultimate power consumption of the TPS is estimated about 12.5MW. To cope with increasing power requirement, we have conducting several power saving schemes for years. This paper presents our latest power schemes, which include installation of power saving fan for the cooling tower, adjustment of supply air temperature according to the atmosphere enthalpy, replacement of old air conditioning unit (AHU), power consumption control by the operation of chillers, and power factor improvement.

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THPMY035

The Real-time Remote Monitoring of Electric Power System Condition at NSRRC

monitoring, real-time, high-voltage, status

3737

T.-S. Ueng, J.-C. Chang, C.S. Chen, Y.F. Chiu, K.C. Kuo, Y.-C. Lin
NSRRC, Hsinchu, Taiwan

For monitoring effectively the real time status of NSRRC's electric power system, an electric power quality monitoring system has been set up to measure the power quality of high voltage feeders, which includes the voltage/current phase, the variation of frequency, voltage sags and swells. The measured result will be analyzed and used to further improve the performance of power system. Furthermore, a partial discharge monitoring system was also installed to monitor the phenomena of electric discharges. Using the ultra high frequency discharge sensor, the magnitude and the pulse-per-second of discharge are measured and analysed. It allows the electrical engineers to diagnose the degradation of insulation of the electric equipment beforehand to reduce the power failure.

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THPMY037

Realization of a System to Monitor Water Quality and for Cooling a TPS KEKB Superconducting Cavity CPL/HOM

HOM, cavity, superconducting-cavity, monitoring

3740

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

Taiwan Photon Source (TPS) is a 3GeV synchrotron accelerator and is built next to the present Taiwan Light Source (TLS) [1]. The stability of electron beam is pro-vided by Low-level RF control system for keeping Gap voltage and phase to be constant[2]. The Gap voltage for accelerating electron beam is provided by KEKB super-conducting cavity. During routine operation of the super-conducting cavity, water cooling system is necessary for stabilize the accessory components of the cavity to avoid damage or abnormal of the system. This article would introduce the realization and integration of the water quality monitoring and cooling system for TPS supercon-ducting cavity input coupler and high order mode damper (CPL/HOM). Brief description is shown in first section. The detail architecture and function of the designed signal monitoring system will be discussed in 2nd section. The 3rd section will have further description of interlocks for system protection. The final section would summarize the water quality monitoring and cooling system in this article.

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THPOR005

Tunnel Level Variation in the SuperKEKB Interaction Region

radiation, alignment, luminosity, feedback

3774

M. Masuzawa, T. Adachi, T. Kawamoto
KEK, Ibaraki, Japan

SuperKEKB is an electron-positron collider, which aims to achieve a peak luminosity 40 times higher than that of KEKB. The vertical beam sizes of both rings are squeezed down to 50 - 60 nm at the interaction point (IP), which accounts for a factor of 20 in the luminosity increase, and the beam currents are doubled from those of KEKB. Tunnel motion can be critical for realizing the collisions of such small beams. A Hydrostatic Leveling System (HLS), which consists of 18 sensors, was installed on both sides of the IP to monitor tunnel level variations continuously. Effects of heavy rain and installation of the radiation shield blocks on the tunnel floor level are clearly seen. The HLS data during construction and SuperKEKB commissioning are reported.

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THPOR024

Electrical Power Budget for FCC-ee

collider, cavity, klystron, cryogenics

3828

F. Zimmermann, S. Aull, M. Benedikt, D. Bozzini, O. Brunner, J.-P. Burnet, A.C. Butterworth, R. Calaga, E. Jensen, V. Mertens, A. Milanese, M. Nonis, N. Schwerg, L.J. Tavian, J. Wenninger
CERN, Geneva, Switzerland
A.P. Blondel, M. Koratzinos
DPNC, Genève, Switzerland
Sh. Gorgi Zadeh
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
K. Oide
KEK, Ibaraki, Japan
L. Rinolfi
JUAS, Archamps, France

Funding: Supported by the European Commission under the Capacities 7th Framework Programme project EuCARD-2, grant agreement 312453.
We present a first rough estimate for the electrical power consumption of the FCC-ee lepton collider. This electrical power is dominated by the RF system, which provides the motivation for the ongoing R&D on highly efficient RF power sources. Other contributions come from the warm arc magnets, the cryogenics systems, cooling, ventilation, general services, the particle-physics detectors, and the injector complex.

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THPOR032

Effect and Optimisation of Non-Linear Chromatic Aberrations of the CLIC Drive Beam Recombination at CTF3

optics, emittance, simulation, sextupole

3852

D. Gamba, R. Corsini, P.K. Skowroński, F. Tecker
CERN, Geneva, Switzerland
P. Burrows
JAI, Oxford, United Kingdom
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

The CLIC design relies on the two-beam acceleration principle, i.e. the energy transfer from the so called drive beam to the main colliding beams. At the CLIC Test Facility (CTF3) at CERN the feasibility of this principle is being tested in terms of performance and achievable specifications. The high-current drive beam is generated by recombining its parts in a delay loop and a combiner ring. Preserving the drive beam emittance during the recombination process is crucial to ensure beam-current and power production stability. Present theoretical and experimental studies show that non-linear energy dependence of the transverse optics heavily spoils the quality of the recombined beam. Conventionally these effects are cured by means of non-linear corrections using sextupoles. In this work we propose a mitigation of these effects by optimising the linear lattice, leading to a more robust and easy to operate drive beam recombination complex. The latest results are presented.

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THPOR033

Integration and Testing of 3 Consecutive CLIC Two-Beam Modules

vacuum, alignment, collider, feedback

3856

A.L. Vamvakas, M. Aicheler, S. Döbert, M. Duquenne, H.M. Durand, M. Sosin, J.I. Väinölä
CERN, Geneva, Switzerland
V. Rude
ESGT-CNAM, Le Mans, France

CLIC (Compact LInear Collider) is a study of a 50 km long linear electron-positron collider, consisting of ap-proximately 20,000 repetitive 2 m long modules. Micron level manufacturing and alignment tolerances are re-quired for the RF and magnet components due to the nanometre beam size and luminosity goal. The effect of thermal, vacuum and mechanical loads needs to be as-sessed, both in transient and in steady state conditions. The dynamic behaviour of mock-ups was investigated on the prototype two-beam module. Two additional two-beam modules are installed to further investigate the interconnections between them, in a machine-like envi-ronment. The array of three consecutive modules allows for alignment tests of the module sequence, while thermal and vacuum tests can be executed simultaneously. A transportation experiment is foreseen, investigating the feasibility of installing prealigned modules. Finally, new design of components is being tested, based on the expe-rience gathered from the first module and leading to a new generation module.

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THPOR034

Bunch-by-bunch Position and Angle Stabilisation at ATF based on Sub-micron Resolution Stripline Beam Position Monitors

feedback, extraction, kicker, linear-collider

3859

N. Blaskovic Kraljevic, R.M. Bodenstein, T. Bromwich, P. Burrows, G.B. Christian, M.R. Davis, C. Perry, R.L. Ramjiawan
JAI, Oxford, United Kingdom
D.R. Bett
CERN, Geneva, Switzerland

A low-latency, sub-micron resolution stripline beam position monitoring (BPM) system has been developed and tested with beam at the KEK Accelerator Test Facility (ATF2), where it has been used to drive a beam stabilisation system. The fast analogue front-end signal processor is based on a single-stage radio-frequency down-mixer, with a measured latency of 16 ns and a demonstrated single-pass beam position resolution of below 300 nm using a beam with a bunch charge of approximately 1 nC. The BPM position data are digitised on a digital feedback board which is used to drive a pair of kickers local to the BPMs and nominally orthogonal in phase in closed-loop feedback mode, thus achieving both beam position and angle stabilisation. We report the reduction in jitter as measured at a witness stripline BPM located 30 metres downstream of the feedback system and its propagation to the ATF interaction point.

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THPOR041

High Gradient Properties of a CLIC Prototype Accelerating Structure made by Tsinghua University

timing, accelerating-gradient, vacuum, experiment

3874

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

A CLIC prototype structure, T24_THU_#1, was recently high-gradient tested at KEK X-band test stand, Nextef. The copper parts of this 24-cell TW structure were delivered from CERN, were bonded and brazed, bench-tested and tuned in Tsinghua University. The aim of this test was not only to verify the cavity high-gradient properties under 100 MV/m but also to study the breakdown phenomenon in high gradient. High power test results were presented and breakdown rate under 100 MV/m was compared to previously-tested CLIC prototype structures. The assembly capability of Tsinghua University for X-band high gradient structures was validated by the good high gradient performance of T24_THU_#1.

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THPOR042

New Quantity Describing the Pulse Shape Dependence of the High Gradient Limit in Single Cell Standing-Wave Accelerating Structures

vacuum, radiation, data-analysis, experiment

3878

J. Shi, H.B. Chen, X.W. Wu
TUB, Beijing, People's Republic of China
V.A. Dolgashev
SLAC, Menlo Park, California, USA
A. Grudiev, W. Wuensch
CERN, Geneva, Switzerland
Y. Higashi
KEK, Ibaraki, Japan
B. Spataro
INFN/LNF, Frascati (Roma), Italy

A new quantity has been developed to study the relationship among the breakdown rate, the pulse width and the gradient. Difference pulse shapes can be treated by introducing a Green's function. This paper describes the quantity and the results while it is applied to the data of many high-power test runs of different single-cell standing wave accelerating structures. A remarkably similar relationship between the new quantity and breakdown rate is observed from all of the test results.

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THPOR043

High Power Test of X-band Single Cell HOM-free Choke-mode Damped Accelerating Structure made by Tsinghua University

cavity, vacuum, HOM, coupling

3881

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

As an alternative design for 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 with different choke dimensions which are working at 11.424 GHz were designed, manufactured and bench tested by accelerator group in Tsinghua University. High power test was carried out on it to study the breakdown phenomenon in high gradient. A single cell structure without choke which almost has the same inner dimension as choke-mode cavity will also be tested to make a comparison and study how the choke affects high-gradient properties.

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THPOR046

CEPC 650 MHz Klystron Development

klystron, gun, simulation, electron

3891

Z.S. Zhou, D. Dong, S. Fukuda, Z.J. Lu, G. Pei, S.C. Wang, O. Xiao, .. Zaib-un-Nisa
IHEP, Beijing, People's Republic of China
S. Fukuda
KEK, Ibaraki, Japan

The CEPC collider beam power is about 100 MW, so the efficiency of amplifier is very important for cost of project implementation. The high power klystron is the more attractive because of its potential for higher eﬃciency than solid state amplifier. For CEPC klystron output power is not so high, the operation voltage can be a safe value. Advantage for single beam: reliable, low phase noise, some perspective technology can be used to improve efficiency. The accelerating frequency is 650 MHz, output power is a maximum power of 800kW, and efficiency is about 70%. In this paper, the specifications and developments of 650 MHz CW klystron, including the klystron gun prototype and future high efficiency consideration are summarized.

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THPOR051

Beam Based Measurements to Check Integrity of LHC Dump Protection Elements

extraction, kicker, proton, vacuum

3908

C. Bracco, W. Bartmann, M.A. Fraser, B. Goddard, A. Lechner
CERN, Geneva, Switzerland

LHC operation is approaching its nominal operating goals and several upgrades are also being prepared to increase the beam intensity and brightness. In case of an asynchronous beam dump at 6.5 - 7 TeV a non-negligible fraction of the stored energy (360 MJ during nominal operation) will be deposited on the protection elements (TCDQ and TCDS) located downstream of the extraction kickers. These elements are designed to protect the machine aperture from the large amplitude particles resulting from the asynchronous dump. A number of checks and measurements with beam have been worked out to verify the integrity of these elements, after a potentially harmful event, without opening the machine vacuum. Details on measurements and simulations performed to evaluate the validity of the proposed method are presented in this paper.

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THPOR052

A Beam-based Measurement of the LHC Beam Dump Kicker Waveform

extraction, kicker, simulation, dumping

3911

M.A. Fraser, W. Bartmann, C. Bracco, E. Carlier, B. Goddard, V. Kain, N. Magnin, J.A. Uythoven, F.M. Velotti
CERN, Geneva, Switzerland

The increase of the LHC collision energy to 13 TeV after Long Shutdown 1 has doubled the operational energy range of the LHC beam dump system (LBDS) during Run 2. In preparation for the safe operation of the LHC, the waveform of the LBDS extraction kicker was measured using beam-based measurements for the first time during the machine's re-commissioning period. The measurements provide a reference for a more precise synchronisation of the dump system and abort-gap timing, and provide an independent check of the system's calibration. The precision of the beam-based technique allowed the necessary adjustments to the LBDS trigger delays to ensure the synchronous firing of the LBDS at all beam energies up to 6.5 TeV. In this paper the measurement and simulation campaign is described and the performance of the system reported.

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THPOR054

Analysis of the SPS Long Term Orbit Drifts

extraction, closed-orbit, dipole, injection

3914

F.M. Velotti, C. Bracco, K. Cornelis, L.N. Drøsdal, M.A. Fraser, B. Goddard, V. Kain, M. Meddahi
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA

The Super Proton Synchrotron (SPS) is the last accelerator in the Large Hadron Collider (LHC) injector chain, and has to deliver the two high-intensity 450 GeV proton beams to the LHC. The transport from SPS to LHC is done through the two Transfer Lines (TL), TI2 and TI8, for Beam 1 (B1) and Beam 2 (B2) respectively. During the first LHC operation period Run 1, a long term drift of the SPS orbit was observed, causing changes in the LHC injection due to the resulting changes in the TL trajectories. This translated into longer LHC turnaround because of the necessity to periodically correct the TL trajectories in order to preserve the beam quality at injection into the LHC. Different sources for the SPS orbit drifts have been investigated: each of them can account only partially for the total orbit drift observed. In this paper, the possible sources of such drift are described, together with the simulated and measured effect they cause. Possible solutions and countermeasures are also discussed.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR054

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THPOW008

DC Photoemission Gun Upgrade at the Compact ERL

gun, high-voltage, FEL, vacuum

3944

N. Nishimori, R. Hajima, R. Nagai
JAEA, Ibaraki-ken, Japan
Y. Honda, T. Miyajima, T. Uchiyama, M. Yamamoto
KEK, Ibaraki, Japan
M. Mori
JAEA/Kansai, Kyoto, Japan

Funding: This work is partially supported by a JSPS Grant-in-Aid for Scientific Research in Japan (15H03594).
The DC photoemission gun at the compact ERL (cERL) has stably provided beam for ERL commissioning and laser Compton scattering experiments since April 2013. The operational voltage has however been limited to 390 kV due to failures of two segments out of the ten segmented insulator. In order to recover 500 kV operation, we installed an additional two segmented insulator on the existing ten segmented insulator during summer shutdown in 2015. The details of the gun upgrade and the operational experience of the upgraded cERL gun will be presented.

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THPOW015

Study of the Performance of Cs2Te Cathodes in the PHIN RF Photoinjector using Long Pulse Trains

cathode, vacuum, laser, electron

3960

C. Heßler, E. Chevallay, S. Döbert, V. Fedosseev, F. Friebel, I. Martini, M. Martyanov, H. Neupert, V. Nistor, M. Taborelli
CERN, Geneva, Switzerland

The drive beam of CLIC requires unusually high peak and average currents which is challenging for the electron source. As an alternative to the thermionic electron gun foreseen in the baseline design, a photoinjector option is under study at CERN using the PHIN photoinjector, which was designed for a bunch charge of 2.3 nC and 1200 ns train length. During operation with nominal train length in 2014, a large pressure increase in the vacuum system, attributed to a heating of the Faraday cup, caused a degradation of the photocathode. To overcome this problem a vacuum window has been installed to separate the Faraday cup from the rest of the vacuum system. In addition the train length has been further increased to 1600 ns to advance the beam parameters towards CLIC requirements. In this paper recent improved photocathode lifetime measurements carried out under these new conditions will be presented and compared with earlier measurements. Furthermore, the utilized Cs2Te cathode has been analyzed with X-ray Photoelectron Spectroscopy (XPS) before and after its usage in PHIN to get a better understanding of photocathode surface deterioration effects, which will also be discussed.

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THPOW017

VELA Photoinjector Cavity RF Investigations

cathode, cavity, simulation, electron

3968

L.S. Cowie, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
J.A. Mitchell
Lancaster University, Lancaster, United Kingdom
M.D. Roper
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

One of two ALPHA-X photocathode gun cavities, designed and fabricated at the Laboratoire de l'Accélérateur Linéaire, has been in operation on the VELA electron accelerator at Daresbury Laboratory since first beam in April 2013. In this time the maximum beam momentum recorded is 5.06 MeV/c. An investigation of the cavity has been performed with the aim of reconciling the expected momentum of over 6 MeV/c with the measured momentum. RF and beam simulation results are presented along with low power RF measurements of the cavity. One source of momentum loss, the flatness of the cathode face, is identified and rectified.

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THPOW032

Experimental Test on the TPS Booster Injection Scheme Exploration and the Associated Bunch Train Analysis

injection, booster, kicker, septum

4008

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

In order to explore the tuning range of injection septum and kicker for TPS booster operation, an experimental test on the designed injection scheme has been performed. Tuning of these injection units is based on the top-up operation process for storage ring vacuum cleaning purpose. It is set for a fast beam accumulation in the storage ring where the stored beam variation range is selected for efficient operation consideration. The measurement results of booster beam current variation while tuning of injection septum and kicker are presented. A preliminary analysis concerning the observation of deteriorated phase space acceptance in the TPS booster is given in this report. This study also includes an effort to extend the present available operation bunch train for TPS booster. It shows that the increase of the booster beam current by bunch train tuning indicates an upper bound of about 400 ns.

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THPOW035

Statistical Analysis Package for the Opearion Monitoring at the TLS

database, photon, Windows, target

4019

Y.K. Lin, H.H. Chen, H.C. Chen, S.J. Huang, C.H. Kuo, A.P. Lee, J.A. Li
NSRRC, Hsinchu, Taiwan

Machine operation parameters and interruptions to user beam at Taiwan Light Source (TLS) and Taiwan Photon Source (TPS) are recorded in databases. The data retrieve to TLS uses the File Transfer Protocol (FTP) with two separated databases 10 Hz and 0.1 Hz for quick or detail data analysis options. TPS data storage uses the open source database PostgreSQL. A statistical analysis package HISTORY has been writ-ten in Microsoft Visual C to perform operation monitor-ing and data mining. Operation and failure statistics func-tions are produced for performance evaluation and User Administration & Promotion Office user time statistics.

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THPOW036

Evaluation of Immutability against Radiation-induced Demagnetization for a Hybrid Wiggler with NdFeB Magnets at the Canadian Light Source

radiation, wiggler, electron, injection

4022

C.K. Baribeau, D. Bertwistle, L.O. Dallin, J.M. Vogt, W.A. Wurtz
CLS, Saskatoon, Saskatchewan, Canada

The BioXAS beamline at Canadian Light Source installed a hybrid wiggler in 2013. Quantitative studies building on the experience of other facilities suggest the wiggler's NdFeB magnets are at risk of demagnetization due to radiation induced by the synchrotron's 2.9 GeV electrons. We use a phenomenological model to convert simulated peak demagnetizing fields into a radiation dose corresponding to a chosen %-demagnetization, and compare against an estimated dose per year due to injected beam. We find that injecting with the wiggler closed will cause 1% demagnetization in sections of its magnet blocks within 2 years of operation, assuming a worst case scenario. The wiggler has thus far been forced open for injections, but this will cease to be an option when CLS moves to top-up operation. In a related test, qualitative measurements of radiation during injections with the wiggler closed were taken by covering its magnets in Polaroid film. We find that radiation drops significantly when the injection efficiency is well-tuned. Our results suggest the wiggler will not receive damaging levels of radiation at closed gap so long as the injection system remains optimized.

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THPOW041

Field Error Correction Considerations of Cryogenic Permanent Magnet Undulator (CPMU) for High Energy Photon Source Test Facility (HEPS-TF)*

cryogenics, undulator, simulation, electron

4038

Y.F. Yang, H.H. Lu, S.C. Sun, X.Z. Zhang
IHEP, Beijing, People's Republic of China

Considerations are made for field error corrections of a 2m-long CPMU in built for HEPS-TF. Field changes in cooling to liquid nitrogen temperature are simulated. 1st field integral of terminal changes by tens of Gauss cm and RMS of phase errors induced by cold contraction is less than 1° when temperature gradient along girder is below 1.5K/m. Field signature of magic finger is unchanged with temperature. Strategy of the field error correction is discussed.

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THPOW058

Drive Laser System for the DC-SRF Photoinjector at Peking University

laser, SRF, electron, optics

4076

F.M. Liu, L.W. Feng, S. Huang, L. Lin, K.X. Liu, S.Y. Si, Zh.W. Wang, G. Zhao
PKU, Beijing, People's Republic of China

The DC-SRF photoinjector, developed at Peking University, uses Cs2Te as the photocathode and accordingly 266 nm laser is used as the drive laser. A drive laser sys-tem，which includes a 1064 nm laser oscillator, a four-stage amplifier, and second and fourth harmonic genera-tors, has been designed and applied successfully. To avoid the high average current electron beam from hitting the vacuum tube and causing safety problems, a laser pulse selector with an EO modulator has been designed and included into the laser drive system to reduce the repetition rate of electron pulses during the DC-SRF photoinjector commissioning. It can adjust the repetition rate of laser pulses from 81.25 kHz to 81.25 MHz. In this paper, we introduce the drive laser system and describe the laser pulse selector in detail.

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THPOY005

Virtual Accelerator System for Online and Offline Simulations

controls, EPICS, lattice, synchrotron

4094

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

Synchrotron radiation light sources have been becoming import scientific tools in various research areas. To build a state-of-the-art synchrotron radiation light source, one need to carefully study the linear and nonlinear dynamics of the charged beam in each of the light source components, such as the linac, transfer line, booster synchrotron and storage ring. There are many mature software tools, including MAD, elegant and Accelerator toolkit (AT), can be used to accomplish these tasks. In order to achieve a high performance light source, up-to-date technologies are adopt to build various subsystems. The integration of these subsystems need to be fully tested before the light source is operated. However, there lacks of a good software to perform this work. The virtual light source (VLS), a software based upon EPICS and AT, is developed at the National Synchrotron Radiation Laboratory (NSRL) to fulfill this purpose. This paper presents the details of this software. Some critical applications are also illustrated.

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THPOY009

Control System of the C-Band Standing-Wave Accelerator for the Medical Application

linac, controls, monitoring, interface

4104

H. Lim, D.H. Jeong, M.W. Lee, M.J. Lee, S.W. Shin, J. Yi
Dongnam Institute of Radiological and Medical Sciences, Busan, Republic of Korea

A control system has been developed for the 6 MeV C-band accelerator which will be used for the medical application. It is built in the PXI platform and implemented for the operation and the monitoring of sub-components by the LabView programs. To communicate with components in the RF noise environment and to send/store the various monitoring data to the storage server, the interface based on Ethernet is used and it allows the real-time monitoring and the safe and fast feed-back system. In order to achieve the beam stability < 3.3 %, the automatic frequency controller for the magnetron is implemented by the feed-back scheme using the frequency waveform data and the constant cavity temperature is controlled by the real-time monitoring and interlock. In addition, the dose rate and flatness are controlled by a monitor chamber. The interlock system is also designed to protect the patients and also linac components against the improper operation, largely radiation, the misbehavior of monitoring parameters, etc. The architecture and main features are described and operation results are reported.

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THPOY017

Design and Implementation of Embedded Applications with EPICS Support for Accelerator Controls

EPICS, controls, interface, embedded

4122

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

Low-cost credit-card size SBCs (single-board computer) are with small footprint, powerful in CPU performance and rich interfaces solution to widely adopted for educational purposes and also suitable for small scale embedded applications. The card-size SBCs have been applied for several applications with EPICS support at the TPS control system environment as auxiliary supports which are not suitable to use standard platform in existed control system due to economics, simplicity, specialty view points. The more efforts of several implemented applications are summarized in this paper.

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THPOY018

Main Operation Improvements on Taiwan Light Source

feedback, power-supply, controls, FPGA

4125

C.H. Kuo, H.H. Chen, H.C. Chen, K.T. Hsu, S.J. Huang, J.A. Li, C.Y. Liao, M.-C. Lin, Y.K. Lin, Y.-C. Liu
NSRRC, Hsinchu, Taiwan

With the beam energy of 1.5 GeV, the storage ring of Taiwan Light Source (TLS) in National Synchrotron Radiation Research Center (NSRRC) has provided research service to users for more than twenty years. It takes a lot of efforts to keep this accelerator reliable and to improve its stability. NSRRC has finished the construction and commissioning of the new 3-GeV accelerator Taiwan Photon Source (TPS) which will be opened to users with limited beam lines in 2016. On the other hand, TLS has 25 beamlines and still serves users very well as being benefited by its mature operation skills and continuous efforts on maintenance and system improvement. Main challenges and corresponding solutions on TLS operation in these recent years t are presented herein, together with the statistics on operation performance.

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THPOY020

Neural Network Modeling of the PXIE RFQ Cooling System and Resonant Frequency Response

rfq, network, controls, cavity

4131

A.L. Edelen, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA
D.L. Bowring, B.E. Chase, J.P. Edelen, J. Steimel
Fermilab, Batavia, Illinois, USA

As part of the PIP-II Injector Experiment (PXIE) accel-erator, a four-vane radio frequency quadrupole (RFQ) accelerates a 30-keV, 1-mA to 10-mA H' ion beam to 2.1 MeV. It is designed to operate at a frequency of 162.5 MHz with arbitrary duty factor, including continuous wave (CW) mode. The resonant frequency is controlled solely by a water-cooling system. We present an initial neural network model of the RFQ frequency response to changes in the cooling system and RF power conditions during pulsed operation. A neural network model will be used in a model predictive control scheme to regulate the resonant frequency of the RFQ.

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THPOY022

Database Development for NSLS-II Accelerator Data Management

database, interface, status, lattice

4137

J. Choi, T.V. Shaftan
BNL, Upton, Long Island, New York, USA

Funding: DOE contract No: DE-SC0012704
NSLS-II is developing a database which will be used for the accelerator data management. The information related to the operation is the main target at this stage. Also, various documents are being collected to provide easy access and installing workflow management is under consideration. The database will have web-based interfaces to communicate with the users. This paper overviews the database structures and required functionalities.

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THPOY023

Upgrade of NSLS-II Active Interlock System

storage-ring, synchrotron, synchrotron-radiation, radiation

4140

S. Seletskiy, J. Choi, K. Ha, R.M. Smith
BNL, Upton, Long Island, New York, USA

The NSLS-II Storage Ring is protected from possible damage from synchrotron radiation by a dedicated active interlock system (AIS). The AIS monitors electron beam position and angle and triggers beam drop if beam orbit exceeds the boundaries of pre-calculated active interlock envelope. The one year worth of the AIS operation showed that there is a number of erroneous machine trips associated with the AIS. In this paper we describe an upgrade of the AIS that allowed us to get rid of the Storage Ring faults and improved the overall NSLS-II reliability.

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THPOY025

From Standby Operation to Patient Treatment in 13 Months: Setting Up the MIT Accelerator Team

ion, controls, ion-source, linac

4146

A. Peters, Th. Haberer
HIT, Heidelberg, Germany
U. Scheeler
MIT, Marburg, Germany

When the University Hospital Heidelberg took over the responsibility for the Marburg Ionbeam Therapy Centre (MIT), HIT as their daughter company was mandated to build up the operation team, especially for the accelerator. Based on long-standing experiences of HIT a very similar personnel concept was already available to be adapted to the MIT specialties. Within 9 months the directly started hiring process resulted in three technical teams with excellent engineers and technicians but with little or no accelerator experience. In parallel, three accelerator physicists were appointed for the executive team of MIT. Nevertheless for all hired persons a training program was set up consisting of technical instructions, lectures on fundamental accelerator physics and control system basics. These common trainings were complemented by individual skills development schedules for the tasks in the technical teams. HIT accelerator experts substantially carried out the recommissioning but in addition the new MIT employees were trained in designated shifts in the control room. Thus after only 13 months the MIT operation crew was able to operate the accelerator facility from the first patient treatment day on.

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THPOY026

Recent Challenges for the 1.5 GeV MAMI-C Accelerator at JGU Mainz

electron, polarization, microtron, experiment

4149

M. Dehn, K. Aulenbacher, H.-J. Kreidel, F. Nillius, B.S. Schlimme, V. Tioukine
IKP, Mainz, Germany

Funding: Work supported by DFG (CRC 1044) and the German federal state of Rhineland-Palatinate
The MAMI-C accelerator is a 1.5 GeV microtron cascade for up to 100 μA polarised electrons operating CW at Mainz University. Recent experiments required spin manipulations and beam energies not routinely supported by the accelerator. In particular, this required a spin orientation vertical to the accelerator plane and operation at beam energies which could not be achieved by the so far established methods. This paper describes the challenges to provide and to characterise the unusual modes of operation.

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THPOY028

Operational Status of HLS-II

cavity, vacuum, storage-ring, electron

4155

J.Y. Li, G. Huang, W. Wei, W. Xu, K. Xuan, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

After a major renovation, the Hefei light source (HLS), renamed HLS_II, was brought into operation in the beginning of 2015. The operational result shows that the HLS-II not only provides much brighter synchrotron radiation beam for various users, but also shows much higher reliability than the old light source. This paper first gives an overview of the HLS-II. The overall performance of the light source is then summarized in this paper. Some measured key parameters of the light source, including emittance, orbit stability, beam lifetime and so on, are also presented.

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THPOY030

Dependability Studies for CERN PS Booster RF System Upgrade

electronics, PLC, interlocks, booster

4159

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

Radio frequency systems are a vital part of almost all accelerators. The request for a higher beam bright-ness from the injector chain of CERN's Large Hardon Collider, as demanded by the future High-Luminosity program, has motivated, among many other upgrades, the construction of new RF equipment in the PS Boost-er. Because availability and reliability have an im-portant impact on the luminosity production in a col-lider environment, dependability studies have been performed on the new design of the RF system assum-ing different maintenance strategies. This paper will present the model, made with the commercial software Isograph, for dependability studies. In addition, a comparative study will be presented between the re-sults obtained from Isograph and from an analytical analysis.

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THPOY034

Simulations of the Beam Loss Distribution at J-PARC Main Ring

proton, simulation, scattering, radiation

4175

B. Yee-Rendón, H. Kuboki, Y. Sato, K. Satou, M.J. Shirakata, T. Toyama
KEK, Ibaraki, Japan
H. Harada
JAEA/J-PARC, Tokai-mura, Japan

The Japan Proton Accelerator Research Complex (J-PARC) is integrated by a set of high intensity proton accelerators. At this operation level, the monitoring and control of the beam losses and residual radiation are priority for its safe performance and maintenance. At Main Ring (MR), a discrepancy appears between the beam loss signal detected by the monitors and the residual dose measured. To understand this difference and the mechanism that produces these losses, a beam simulation study is implemented using the Strategic Accelerator Design (SAD) and Geometry and Tracking (Geant4) code. The first stage of the survey uses SAD to obtain the location of the losses around the lattice per turn. Then, Geant4 produces the secondary showers in the elements. Finally, we make the extrapolation with the residual radiation and compare with the measurements. The description and results of this work are presented in this paper.

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THPOY035

Machine Protection and Safe Operation of LIPAc Linear Accelerator

rfq, linac, SRF, vacuum

4178

A. Marqueta, J. Knaster, K. Nishiyama
IFMIF/EVEDA, Rokkasho, Japan
P.-Y. Beauvais, H. Dzitko
F4E, Germany
P. Cara
Fusion for Energy, Garching, Germany
H. Kobayashi
KEK, Ibaraki, Japan
I. Podadera
CIEMAT, Madrid, Spain

A Li(d, xn) fusion relevant neutron source with a broad peak at 14 MeV is indispensable to characterize and qualify suitable structural materials for the plasma facing components in future fusion reactors. LIPAc (Linear IFMIF Prototype Accelerator), presently under its installation and commissioning phase in Rokkasho, will validate the concept of a 40 MeV deuteron accelerator with its 125 mA CW and 9 MeV deuteron beam for a total beam average power of 1.125 MW. The Machine Protection System (MPS) of LIPAc provides the essential interlock function of stopping the beam in case of excessive beam loss or other hazardous situations. However, approaching LIPAc beam commissioning Phase B (including RFQ powered by total 1.6 MW RF power) a risk analysis has been performed on all major technical systems to identify the sources of risk, apply the necessary countermeasures and enhance accelerator availability, avoiding unnecessary beam stop triggers and allowing a fast beam recovery whenever possible. The overall strategy for the machine protection at LIPAc is presented in this paper.

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THPOY041

CERN Beam Interlock Redundant Dump Trigger Module Performance during LHC Run 2

dumping, extraction, collider, radiation

4189

D.O. Calcoen, S. Gabourin, A.P. Siemko
CERN, Geneva, Switzerland

During the Long Shutdown 1 an additional link between the Beam Interlocks System and the LHC Beam Dumping System was installed. This third channel is a direct access from the BIS to the asynchronous dump triggering lines. This paper describes the experience collected for the first 10 months of operation and the improvements proposed for a future upgrade of the module.
IPAC 2014 THPRI021

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THPOY042

Evolution and Perspectives of Second Generation Magnet Interlock Systems at CERN

PLC, interlocks, radiation, dipole

4192

I. Romera, Y. Bastian, G. Csendes, P. Dahlen, R. Mompo, C. Von Siebenthal, M. Zerlauth
CERN, Geneva, Switzerland

The CERN accelerator complex relies on thousands of superconducting and normal conducting magnets to guide the particle beams on their trajectories throughout the accelerator chain. In order to protect magnet and powering equipment from damage, complex magnet interlock systems are deployed and operated in the LHC and its injectors. Despite a very good track record during the first 10 years of operation, important consolidation activities are ongoing and planned to further increase the dependability of the injector chain and enhance the sys-tem functionality where required. This paper reviews the performance of the various magnet interlock systems at CERN during the past years of operation and presents the ongoing renovation projects carried out in the LHC in-jector complex to achieve the high level of dependability and maintainability required for long term operation. Finally, some design aspects of the existing LHC magnet interlocks will be discussed and possibilities to further enhance the dependability and functionality of the mag-net powering system will be presented in view of the High Luminosity LHC.

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THPOY045

Commissioning of the Machine Protection Systems of the Large Hadron Collider Following its First Long Shutdown

dipole, injection, hadron, beam-losses

4203

D. Wollmann, R. Schmidt, J.A. Uythoven, J. Wenninger, M. Zerlauth
CERN, Geneva, Switzerland

During the first long shutdown of the Large Hadron Collider (LHC) extending for more than 18 months, most Machine Protection Systems (MPS) have undergone significant changes, and upgrades. A full re-commissioning of the MPS was performed at the end of the shutdown and during the LHC beam commissioning in 2015. To verify the correct functioning of all protection-relevant systems with beam, a step-wise intensity ramp-up was performed, reaching at the end of 2015 a record stored beam energy of ~280 MJ per beam, nearly 80% of the value in the design report. This contribution summarizes the results of the MPS commissioning, the intensity ramp-up and the continuous follow-up during operation, focusing mainly on near misses and false triggers and their proposed mitigations. A strategy to minimize risks during machine development periods for future operation of the LHC, when the protection parameters are modified for several tests, is discussed. The machine protection strategy for the LHC run in 2016 is presented.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY045

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THPOY046

Data Analysis and System Survey Framework for the LHC Beam Loss Monitoring System

framework, detector, status, database

4207

C. Xu, B. Dehning, C. Zamantzas
CERN, Geneva, Switzerland

A data analysis framework has been developed to perform systematic queries and automatic analysis of the large amount of data produced by the LHC beam loss monitoring system. The framework is used to provide continuous system supervision and can give advance warning of any potential system failures. It is also used to facilitate LHC beam loss analysis for determining the critical beam-abort threshold values. This paper describes the functionality of the framework and the results achieved from the analysis.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY046

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THPOY048

NSLS-II Active Interlock System and Post-Mortem Architecture

timing, status, FPGA, hardware

4214

K. Ha, E.B. Blum, W.X. Cheng, J. Choi, Y. Hu, D. Padrazo, S. Seletskiy, O. Singh, R.M. Smith, J. Tagger, Y. Tian, G. Wang, T. Yang
BNL, Upton, New York, USA

The NSLS-II at Brookhaven National Laboratory (BNL) started the user beam service in early 2015, and is currently operating 13 of the insertion device (ID) and beamlines as well as constructing new beamlines. The fast machine protection consists of an active interlock system (AIS), beam position monitor (BPM), cell controller (CCs) and front-end (FE) systems. The AIS measures the electron beam envelop and the dumps the beam by turning off RF system, and then the diagnostic system provides the post-mortem data for an analysis of which system caused the beam dump and the machine status analysis. NSLS-II post-mortem system involves AIS, CCs, BPMs, radio frequency system (RFs), power supply systems (PSs) as well as the timing system. This paper describes the AIS architecture and PM performance for NSLS-II safe operations.

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FRXBA01

Beam Halo Characterization and Mitigation

emittance, linac, collimation, simulation

4248

A.V. Aleksandrov
ORNL, Oak Ridge, Tennessee, USA

Beam halo is a serious issue in many machines, such as high intensity linacs and synchrotrons. This presentation reviews recent advances in halo characterization techniques, as well as methods to mitigate beam halo, such as collimation with associated handling of created secondary particles.

Slides FRXBA01 [17.743 MB]

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-FRXBA01

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FRYAA03

Accelerator Driven Sustainable Fission Energy

target, neutron, rfq, proton

4271

W.-L. Zhan
CAS, Beijing, People's Republic of China

It is the new approaches of sustainable fission energy that high power accelerator produces intensive external neutron to close fuel cycle and utilize fissile fuel ?95%. The system includes the fissile fuel burner and used fuel recycle. The burner is optimized as the nuclear waste transmutation, fissile material breeding and energy production in situ by the accelerator driven system. There are 4 phases in the Chinese development road map and the new research sites are introduced in this talk as well. The 2nd phase will be finished around 2022, with its high power LINAC (proton beam ~250MeV&10mA) providing the best opportunity to make DAR source for neutrino research. The burner, optimizing from ADS, consists of the high power LINAC, the spallation target and the subcritical core. The 25MeV LINAC prototype will be commissioned by the end of this year. The 10 MeV LINAC has produced a CW proton beam in 10's kW and has been operated with the ion source being operated more than 2000 hrs. The new concept of spallation target is granular fluid target, in which the solid grain fluid and beam implant from top to down. All these sub-systems will be described in this talk.

Slides FRYAA03 [8.741 MB]

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-FRYAA03

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