LINAC2016 - List of Keywords (coupling)

Paper	Title	Other Keywords	Page
MOOP04	Traveling Wave Linear Accelerator With RF Power Flow Outside of Accelerating Cavities	impedance, linac, cavity, electron	48
	V.A. Dolgashev SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. DOE under Contract No. DE-AC02-76-SF00515. An accelerating structure is a critical component of particle accelerators for medical, security, industrial and scientific applications. Standing-wave side-coupled accelerating structures are used where available RF power is at a premium, while average current and average RF power lost in the structure are high. These structures are expensive to manufacture and typically require a circulator to divert structure-reflected power away from RF source, klystron or magnetron. In this report a traveling wave accelerating structure is presented which combines high shunt impedance of the side-coupled standing wave structure with such advantages as simpler tuning and manufacturing. In addition, the structure is matched to the RF source so no circulator is needed. This paper presents the motivation for this structure and shows a practical example.
	Slides MOOP04 [5.459 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOOP04
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MOOP05	Dry-Ice Cleaning of RF-Structures at DESY	cavity, gun, niobium, RF-structure	52
	A. Brinkmann, J. Ziegler DESY, Hamburg, Germany
	Dry-Ice cleaning is today a well established cleaning method in matters of reducing harmful dark current and field emission in copper RF-structures like RF-Guns such as for the European XFEL, FLASH and REGAE. This led to the idea to clean longer RF-structures, in particular 3GHz transverse deflecting structures for the European XFEL. We developed a cleaning device with the possibility to clean up to 2 m long structures in horizontal position with an inner diameter of not more than 40 mm. Furthermore this device also allows to clean 9-cell TESLA-type Nb-cavities as well. A report of the technical layout and results of RF-tests will be given.
	Slides MOOP05 [0.969 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOOP05
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MOPLR006	Monopole HOMs Dumping in the LCLS-II 1.3 GHz Structure	HOM, cavity, linac, damping	142
	A. Lunin, T.N. Khabiboulline, N. Solyak Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE Developing an upgrade of Linac Coherent Light Source (LCLS-II) is currently underway. The central part of LCLS-II is a continuous wave superconducting RF (CW SRF) electron linac. High order modes (HOMs) excited in SRF structures by passing beam may deteriorate beam quality and affect beam stability. In this paper we report the simulation results of monopole High Order Modes (HOM) spectrum in the 1.3 GHz accelerating structure. Optimum parameters of the HOM feedthrough are suggested for minimizing RF losses on the HOM antenna tip and for preserving an efficiency of monopole HOMs damping simultaneously.
	Poster MOPLR006 [0.647 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR006
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MOPLR009	X-Band Travelling Wave Accelerating Section R&D for HTF	electron, operation, cavity, vacuum	152
	K. Jin USTC/NSRL, Hefei, Anhui, People's Republic of China
	Hefei Light Source (HLS) was mainly composed of an 800 MeV electron storage ring and an 800MeV-1GeV constant-gradient accelerator in NSRL. The new Linac with Full Energy Injection and the Top-up Injection scheme has been developed successfully. And the other functioning as X Ray Free Electron Laser test facility has been considered. In the project, in order to compress the bunch length and to achieve the beam energy distribution linearization. A 15MeV, operation frequency 11.424GHz traveling wave accelerating section as harmonic compensation is being developed. In this paper, X Ray Free Electron Laser Hefei Test Facility (HTF) is introduce briefly. And the R&D of the x-band accelerating section with collinear load are presented in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR009
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MOPLR030	Electromagnetic Design of a Superconducting Twin Axis Cavity	cavity, HOM, linac, dipole	203
	S.U. De Silva, J.R. Delayen, H. Park ODU, Norfolk, Virginia, USA A. Hutton, F. Marhauser, H. Park JLab, Newport News, Virginia, USA
	The twin-axis cavity is a new kind of rf superconducting cavity that consists of two parallel beam pipes, which can accelerate or decelerate two spatially separated beams in the same cavity. This configuration is particularly effective for high-current beams with low-energy electrons that will be used for bunched beam cooling of high-energy protons or ions. The new cavity geometry was designed to create a uniform accelerating or decelerating fields for both beams by utilizing a TM110 dipole mode. This paper presents the design rf optimization of a 1497 MHz twin-axis single-cell cavity, which is currently under fabrication.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR030
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MOPLR048	Fabrication and Testing of a Novel S-Band Backward Travelling Wave Accelerating Structure for Proton Therapy Linacs	linac, vacuum, proton, accelerating-gradient	237
	S. Benedetti, T. Argyropoulos, C. Blanch Gutiérrez, N. Catalán Lasheras, A. Degiovanni, D. Esperante Pereira, M. Garlaschè, J. Giner Navarro, A. Grudiev, G. McMonagle, A. Solodko, M.A. Timmins, R. Wegner, B.J. Woolley, W. Wuensch CERN, Geneva, Switzerland D. Esperante Pereira IFIC, Valencia, Spain
	Compact and more affordable, facilities for proton therapy are now entering the market of commercial medical accelerators. At CERN, a joint collaboration between CLIC and TERA Foundation led to the design, fabrication and testing of a high gradient accelerating structure prototype, capable of halving the length of state-of-art light ion therapy linacs. This paper focuses on the mechanical design, fabrication and testing of a first prototype. CLIC standardized bead-pull measurement setup was used, leading to a quick and successful tuning of the prototype. The high power tests will soon start in order to prove that the structure can withstand a very high accelerating gradient while suffering no more than 10^-6 breakdown per pulse per meter (bpp/m), resulting in less than one breakdown per treatment session.
	Poster MOPLR048 [2.804 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR048
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MOPLR053	Operating Status of Injector II RFQ for C-ADS Project	rfq, cavity, impedance, scattering	254
	L.P. Sun, Y. He, C.X. Li, L. Lu, A. Shi, L.B. Shi, W.B. Wang, X.B. Xu, Z.L. Zhang, H.W. Zhao IMP/CAS, Lanzhou, People's Republic of China
	The Radio Frequency Quadrupole system has been designed and constructed for C-ADS (Chinese Accelerator Driven System) Injector II in Institute of Modern Physics (IMP), Chinese Academy of Sciences, which has been running for more than one year until now. It is a quadrilateral four-vane resonator with two equal couplers operating in CW mode. In the paper, RF system upgrade will be presented in detail，especially the two-port configuration was introduced and the conditioning based on two new sets of solid-state amplifier instead of the original tetrodes power source due to system hardware upgrade are described in the paper. RFQ, solid-state amplifier, two-port configuration, coupler
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR053
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MOPLR067	First High Power Tests at the 325 MHz RF Test Stand at GSI	cavity, linac, rfq, klystron	287
	G. Schreiber, E. Plechov, J. Salvatore, B. Schlitt, A. Schnase, M. Vossberg GSI, Darmstadt, Germany
	A dedicated RF test stand for testing RF components and accelerating structures at 325 MHz has been put into operation at GSI. It allows testing the klystrons and circulators as well as the RFQ and the CH-acceleration cavities for the planned FAIR proton linac (p-Linac) and further cavity projects. The system integration has been completed and first high power tests with the CH prototype cavity were successfully performed. The operation parameters are 2 Hz repetition rate and 200 microseconds pulse length. Investigations on the critical path from wave guide to coaxial high power cavity coupler have been made. Performance measurements of the klystron, circulator and directional couplers with up to 2.8 MW on dummy load and the following conditioning process of the CH-prototype cavity with its coupled RF structures will be presented. Additionally the results of the conditioning of a ladder RFQ prototype are shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR067
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TUOP05	First Experiments at the CW-Operated RFQ for Intense Proton Beams	rfq, ion, operation, experiment	394
	P.P. Schneider, D. Born, M. Droba, C. Lorey, O. Meusel, D. Noll, H. Podlech, A. Schempp, B. Thomas, C. Wagner IAP, Frankfurt am Main, Germany
	This contribution describes the first experiments with the cw-operated RFQ, which is designed to accelerate protons from 120keV to 700keV for the FRANZ-Project. The commissioning is done using the RF and ion beam scrubbing technique. In the first phase, the acceptance of the RFQ is scanned and the performance of the RFQ without space-charge effects is evaluated with a 2mA proton beam. The second phase will increase the beam current up to 50mA and a third phase with a machine upgrade for a beam current of up to 200mA is planned. The configuration of a high-current RFQ, transporting beam current increasing from 2mA with no space-charge forces to a beam with high space-charge effects gives an unique insight in the beam optics of the space-charge effects. The measurements are done with a slit-grid emittance scanner for the transversal phase-space, a faraday cup for the transmitted current and a momentum spectrometer to measure the energy spread. The results set the basis for later experiments on variations of the beam current and the future coupling of the RFQ with an IH-structure*. Bechtold, A., et al., MOP001, LINAC08 Meusel, O., et al., MO3A03, LINAC12 * Vossberg, M., et al., WEPFI009, IPAC13 **** Heilmann, M., et al., THPWO017, IPAC13
	Slides TUOP05 [2.435 MB]
	Poster TUOP05 [4.550 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP05
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TUPRC017	Field Flatness and Frequency Tuning of the CLARA High Repetition Rate Photoinjector	cavity, cathode, FEL, gun	452
	L.S. Cowie, P. Goudket, B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom T.J. Jones STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom B. Keune RI Research Instruments GmbH, Bergisch Gladbach, Germany
	The High Repetition Rate Photoinjector, designed for the CLARA FEL at Daresbury Laboratory, was tuned at the manufacturers for both field flatness and frequency. Due to the high average power in the cavity of 6.8 kW the cavity requires significant cooling, achieved by water channels in the cavity body. These channels prohibit the use of tuning studs to tune the cavity. The cavity was tuned by taking pre-braze clamped low power RF measurements and using the data to trim the cavity cells to the optimum length for both field flatness and frequency. The optimum field flatness is 100% and the design frequency is 2998.5 MHz. Both cells were trimmed in 3 stages, resulting in a post-braze frequency of 2998.51 MHz and field flatness of 98%.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPRC017
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TUPLR005	Development of 6 MeV European S-band Side-Coupled Industrial Electron Linear Accelerator at RTX & KAERI	electron, linac, target, gun	478
	P. Buaphad, S.C. Cha KAERI, Jeongeup-si, Republic of Korea P. Buaphad University of Science and Technology of Korea (UST), Daejeon, Republic of Korea P. Buaphad RTX, Daejeon, Republic of Korea Y. Kim ISU, Pocatello, Idaho, USA
	There are growing demands on low energy electron linear accelerator (linac) for industrial applications. Most of industrial electron linacs require a compact structure and limited undesirable neutron production to avoid huge lead shielding. Radiation Technology eXcellence (RTX) and Korea Atomic Energy Research Institute (KAERI) have developed a 6 MeV compact side-coupled linac by using 2998 MHz European S-band RF technology to meet those requirements. To design the linac structure, the 3D CST MICROWAVE STUDIO (CST-MWS) was used for various electromagnetic simulations, and ASTRA code was used for particle beam dynamics simulations. After various optimizations, the shunt impedance of 61 MΩ/m is obtained at 2998.38 MHz. With a peak RF power of 2.2 MW and a 47 cm-long structure, electron beam with a peak current of 150 mA can be accelerated from 25 keV to 6 MeV. For the industrial linac, the electron beam spotsize at an X-ray target, located 5 cm downstream of the linac structure exit should be smaller than 2 mm (FW). In addition, it can supply an X-ray dose rate of 8 Gy/min at 1 m after the X-ray target. In this paper, we describe the design concepts and optimization of the 2998 MHz side-coupled industrial linac structure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPLR005
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TUPLR050	Design of 4-vane RFQ with Magnetic Coupling Windows for Nuclotron Injector Lu-20	rfq, ion, Windows, linac	575
	V.A. Koshelev, G. Kropachev, T. Kulevoy, D.A. Liakin, A.S. Plastun ITEP, Moscow, Russia A.V. Butenko JINR, Dubna, Moscow Region, Russia T. Kulevoy, S.M. Polozov MEPhI, Moscow, Russia S.V. Vinogradov MIPT, Dolgoprudniy, Moscow Region, Russia
	Alvarez-type linac LU-20 is used as Nuclotron injector. In the framework of NICA project the high voltage electrostatic pre-injector for LU-20 has been replaced by RFQ linac. The RFQ was designed by the team of ITEP and MEPhI (Moscow, Russia) and was manufactured in VNIITF (Sneginsk, Russia). The engineering design of the 4-vane RFQ linac with magnetic coupling windows and details of its manufacturing are presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPLR050
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TUPLR058	Progress of a 162.5 MHz High-Current RFQ With Coupling Windows	rfq, Windows, cavity, simulation	589
	Q. Fu, P.P. Gan, S.L. Gao, F.J. Jia, H.P. Li, Y.R. Lu, Z. Wang, K. Zhu PKU, Beijing, People's Republic of China
	Funding: Supported by National Basic Research Program of China(2014CB845503) A 162.5 MHz, four-vane RFQ with magnetic coupling windows has been designed by the RFQ group of Peking University. Clear frequency separation of the resonant modes and smaller transverse dimension are the advantages of the window-type RFQ. The electromagnetic simulations have shown that the average power loss of this 1.809 m long RFQ is about 50 kW in continuous wave mode. Consequently, a water cooling system was designed via the multi-physics analysis. The mechanical design and assembling technology were also presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPLR058
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TUPLR060	RF Design of the Nuclotron-NICA 145.2 MHz RFQ	rfq, Windows, dipole, simulation	595
	A.S. Plastun, V. Andreev, V.A. Koshelev, T. Kulevoy, V.G. Kuzmichev, D.A. Liakin, A. Sitnikov ITEP, Moscow, Russia A.V. Butenko JINR, Dubna, Moscow Region, Russia
	ITEP has designed the Radio-Frequency Quadrupole (RFQ) linac for the JINR NICA Complex (Dubna, Russia) to provide ion beams (q/A ≥ 0.3) with energy of 156 keV/u for further acceleration by existing Alvarez-type linac. The RFQ is based on a 4-vane structure with magnetic coupling windows in order to avoid a risk of excitation of dipole field components inherent in a conventional 4-vane resonator. The paper presents results of the radio-frequency (RF) design and capabilities used for coarse and fine tuning of the field distribution and resonant frequency during manufacturing and finalizing of the RFQ.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPLR060
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WE1A05	HIE-ISOLDE SC Linac Progress and Commissioning in 2016	cryomodule, cavity, linac, cryogenics	663
	W. Venturini Delsolaro, E. Bravin, N. Delruelle, M. Elias, E. Fadakis, J.A. Ferreira Somoza, F. Formenti, M.A. Fraser, J. Gayde, N. Guillotin, Y. Kadi, G. Kautzmann, T. Koettig, Y. Leclercq, M. Martino, M. Mician, A. Miyazaki, E. Montesinos, V. Parma, J.A. Rodriguez, S. Sadovich, E. Siesling, D. Smekens, M. Therasse, L. Valdarno, D. Valuch, G. Vandoni, U. Wagner, P. Zhang CERN, Geneva, Switzerland
	The HIE-ISOLDE project (High Intensity and Energy ISOLDE) reached an important milestone in October 2015 when the first physics run was carried out with radioactive Zn beams at 4 MV/m. This is a first stage in the upgrade of the REX post-accelerator, whereby the energy of the radioactive ion beams was increased from 3 to 4.3 MeV per nucleon. The facility will ultimately be equipped with four high-beta cryomodules that will accelerate the beams up to 10 MeV per nucleon for the heaviest isotopes available at ISOLDE. The first cryomodule of the new linac, hosting five superconducting cavities and one solenoid, was commissioned in summer 2015, while the second one was being assembled in clean room. The new high-energy beam transfer lines were installed and commissioned in the same lapse of time. Commissioning with two cryomodules is planned for Summer 2016 to prepare for a physics run at 5.5 MeV/u in the second half of the year. This contribution will focus on the results of the commissioning and operation of the SC linac in 2015. Plans for the second phase of the HIE-ISOLDE project will be highlighted.
	Slides WE1A05 [4.194 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-WE1A05
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TH1A04	SARAF 4-Rods RFQ RF Power Line Splitting Design and Test	rfq, operation, proton, vacuum	693
	J. Rodnizki, D. Hirschmann, Z. Horvitz, B. Kaizer, A. Perry, L. Weissman Soreq NRC, Yavne, Israel
	In the last years the SARAF 176 MHz 3.8 m long 4-rod RFQ accelerates routinely 2-4 mA CW proton beams to 1.5 MeV for basic studies in physics. However, it has not been successful in running CW deuteron beam for long periods. The findings imply that the RF coupler is the bottle neck to reach 250 kW CW dissipated power, equivalent to 65 kV inter-rod voltage, required to run the CW deuteron beam. A new design that splits the RFQ power between two couplers was built and commissioned successfully. A 3dB splitter and two new RF couplers were installed. The RF couplers improved design allows better brazing methods, vacuum properties and RF sealing. This design is innovative from two points of view: (a) implementation of two synchronized couplers located in two separated RF cells in a 4-rod RFQ. (b) The ability to run the RFQ in 200-250 kW to accelerate a 5 mA CW deuteron beam by 2.6 MV required for the new modulation design for 1.3 MeV/u. To our knowledge, SARAF RFQ will be the first 4-rod RFQ capable of running a CW deuteron beam at these power densities. This work may contribute to other 4-rod RFQ projects which intend to run CW beams in high dissipation power, like FRANZ and MYRRHA.
	Slides TH1A04 [6.109 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TH1A04
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TH2A03	Complete Transverse 4D Beam Characterization for Ions Beams at Energies of Few MeV/u	emittance, quadrupole, ion, vacuum	720
	M.T. Maier, X. Du, P. Gerhard, L. Groening, S. Mickat, H. Vormann GSI, Darmstadt, Germany
	Measurement of the ion beam rms-emittances is done through determination of the second order beam moments. For time being the moments quantifying the amount of inter-plane coupling, as <xy'> for instance, have been accessible to measurements just for very special cases of ions at energies below 200 keV/u using pepperpots. This talk presents successful measurements of all inter-plane coupling moments at 1 to 11 MeV/u. From first principles the used methods are applicable at all ion energies. The first campaign applied skewed quadrupoles in combination with a regular slit/grid emittance measurement device. The second campaign used a rotatable slit/grid device in combination with regular quadrupoles.
	Slides TH2A03 [17.343 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TH2A03
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THPLR011	Traveling Wave Accelerating Structure Power Input Calculation With Equivalent Circuit Method	impedance, operation, interface, resonance	864
	S.V. Matsievskiy, V.I. Kaminskiy MEPhI, Moscow, Russia
	Nowadays linac accelerating RF systems design is usually done by the finite difference method. It provides high accuracy of calculations and freedom in topology choosing, but may draw considerable amounts of computer resources with long calculation times. Alternative to this method, equivalent circuit method exists. The basic idea of this method is to build a lumped element circuit, which with certain approximation acts as an original accelerating cell. It drastically reduces the number of equations to solve. This method is long known but usually only used for the particular accelerating structures when speed of calculation is a key-factor. This paper describes an attempt to create more universal and user-friendly software application for calculating electrical field distribution in accelerating structures, provides mathematical equations this software is based on. The resulting application may be used for preliminary calculations of acceleration structures and help to determine cells electrodynamic parameters reducing overall design time.
	Poster THPLR011 [0.789 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR011
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THPLR018	HOM Suppression Improvement for Mass Production of EXFEL Cavities at RI	cavity, HOM, damping, linac	879
	A.A. Sulimov, J.H. Thie DESY, Hamburg, Germany M. Pekeler, D. Trompetter RI Research Instruments GmbH, Bergisch Gladbach, Germany
	During cold RF tests of the European XFEL (EXFEL) cavities at DESY it was observed that the damping of the second monopole mode (TM011) showed the largest variation, which was sometimes up to 2-3 times lower than the originally allowed limit. It was concluded that this TM011-damping degradation was caused by cavity geometry deviation within the specified mechanical tolerances. The particular influence of different mechanical parameters was analyzed and additional RF measurements were carried out to find the most critical geometry parameters. Stability of the equator welding and regularity of chemical treatment were investigated for different cavity cells. In spite of the high fabrication rate during EXFEL cavity mass production the TM011 suppression was improved to an acceptable level.
	Poster THPLR018 [0.378 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR018
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THPLR040	First Vertical Test of Superconducting QWR Prototype at RIKEN	ion, cryomodule, acceleration, multipactoring	939
	K. Yamada, O. Kamigaito, K. Ozeki, N. Sakamoto, K. Suda, Y. Watanabe RIKEN Nishina Center, Wako, Japan E. Kako, H. Nakai, K. Umemori KEK, Ibaraki, Japan A. Miyamoto, K. Sennyu, T. Yanagisawa MHI-MS, Kobe, Japan
	Development of a superconducting quarter-wavelength resonator (SC-QWR) was started at RIKEN Nishina Center to realize a low-velocity part of high-intensity ion linac. First prototype of the SC-QWR, frequency of which is 75.5 MHz, is fabricating now. Preparation of its partial components such as outer conductor, stem, bottom plate, and top plate was almost completed, and we are now studying a low-power RF property by clamping the every components as an assembly to obtain data for frequency tuning. After the adjustment of geometry of components and welding them, surface treatment by buffered chemical polishing and high-pressure rinsing will be performed in the summer. Preparation of vertical test for the SC-QWR is also in progress at KEK. The first result of vertical test for the prototype of SC-QWR will be presented in this contribution. This work was funded by the ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan). N. Sakamoto et al., Proceedings of SRF2015, WEBA06.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR040
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THPLR060	Experience with the Conditioning of Linac4 RF Cavities	cavity, vacuum, linac, DTL	985
	S. Papadopoulos, F. Gerigk, J.-M. Giguet, J. Hansen, J. Marques Balula, A.I. Michet, S. Ramberger, N. Thaus, R. Wegner CERN, Geneva, Switzerland
	Linac4, the future H⁻ injector of the PS complex at CERN has reached the hardware and beam commissioning phase. This paper summarizes the experience gained in RF conditioning of the DTL, CCDTL and PIMS cavities. The behaviour in conditioning of these cavities strongly depends on the cavity type and assembly conditions. Examples of conditioning history and vacuum measurements before, during and after conditioning are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR060
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THPLR066	Preparation and Installation of IFMIF-EVEDA RFQ at Rokkasho Site	rfq, alignment, cavity, vacuum	1005
	E. Fagotti, L. Antoniazzi, A. Baldo, A. Battistello, P. Bottin, L. Ferrari, M.G. Giacchini, F. Grespan, M. Montis, A. Pisent, D. Scarpa INFN/LNL, Legnaro (PD), Italy D. Agguiaro, A.G. Colombo, A. Pepato, L. Ramina INFN- Sez. di Padova, Padova, Italy F. Borotto Dalla Vecchia, G. Dughera, G. Giraudo, E.A. Macri, P. Mereu, R. Panero INFN-Torino, Torino, Italy
	The IFMIF-EVEDA RFQ is composed of 18 modules for a total length of 9.8 m and is designed to accelerate the 125 mA D⁺ beam up to 5 MeV at the frequency of 175 MHz. The RFQ is subdivided into three Super-Modules of six modules each. The Super-Modules were pre-assembled, aligned and vacuum tested at INFN-LNL and then shipped to Rokkasho (Japan). At Rokkasho site a series of test were performed in order to verify the effect of the shipment on the cavity. The assembly debug, shipment equipment and the sequence of operations are described in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR066
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THPLR067	Series Production of the RF Power Distribution for the European XFEL	cavity, klystron, cryogenics, status	1008
	S. Choroba, V.V. Katalev DESY, Hamburg, Germany E.M. Apostolov Technical University of Sofia, Sofia, Bulgaria
	The RF power distribution for the European XFEL allows for individual RF power for the 808 superconducting cavities of the European XFEL. It consists of a number of elements, not only waveguide components, but also girders, cables or cooling systems. The production of the RF distribution consists of several tasks. In order to deal with the schedule of the entire project a detailed planning, organization and monitoring of the series production of the RF power distribution was required. This paper describes the RF power distribution layout and the series production process.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR067
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THPLR069	Quality Factor Measurement Method Using Multi Decay Time Constants on Cavity	cavity, pick-up, superconducting-cavity, cryomodule	1011
	J.W. Kim, H. Kim IBS, Daejeon, Republic of Korea
	Quality factor measurement method using multi decay time constants on superconducting cavity is suggested. In most cases of vertical test, one decay time constant is measured around critical coupling and coupling constants are measured using forward and reflected rf power to get intrinsic quality factor. We use multi decay time constants method to measure the quality factor, which uses three decay time constants. Two more switches before and after the cavity are added to the measurement system. Decay time constants are measured by switching off the rf power switch in front of rf source, the forward power switch in front of input power coupler, and then the pickup power switch behind the pickup coupler, respectively, at the same power of steady state.
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Paper

Title

Other Keywords

Page

MOOP04

Traveling Wave Linear Accelerator With RF Power Flow Outside of Accelerating Cavities

impedance, linac, cavity, electron

48

V.A. Dolgashev
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. DOE under Contract No. DE-AC02-76-SF00515.
An accelerating structure is a critical component of particle accelerators for medical, security, industrial and scientific applications. Standing-wave side-coupled accelerating structures are used where available RF power is at a premium, while average current and average RF power lost in the structure are high. These structures are expensive to manufacture and typically require a circulator to divert structure-reflected power away from RF source, klystron or magnetron. In this report a traveling wave accelerating structure is presented which combines high shunt impedance of the side-coupled standing wave structure with such advantages as simpler tuning and manufacturing. In addition, the structure is matched to the RF source so no circulator is needed. This paper presents the motivation for this structure and shows a practical example.

Slides MOOP04 [5.459 MB]

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MOOP05

Dry-Ice Cleaning of RF-Structures at DESY

cavity, gun, niobium, RF-structure

52

A. Brinkmann, J. Ziegler
DESY, Hamburg, Germany

Dry-Ice cleaning is today a well established cleaning method in matters of reducing harmful dark current and field emission in copper RF-structures like RF-Guns such as for the European XFEL, FLASH and REGAE. This led to the idea to clean longer RF-structures, in particular 3GHz transverse deflecting structures for the European XFEL. We developed a cleaning device with the possibility to clean up to 2 m long structures in horizontal position with an inner diameter of not more than 40 mm. Furthermore this device also allows to clean 9-cell TESLA-type Nb-cavities as well. A report of the technical layout and results of RF-tests will be given.

Slides MOOP05 [0.969 MB]

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MOPLR006

Monopole HOMs Dumping in the LCLS-II 1.3 GHz Structure

HOM, cavity, linac, damping

142

A. Lunin, T.N. Khabiboulline, N. Solyak
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
Developing an upgrade of Linac Coherent Light Source (LCLS-II) is currently underway. The central part of LCLS-II is a continuous wave superconducting RF (CW SRF) electron linac. High order modes (HOMs) excited in SRF structures by passing beam may deteriorate beam quality and affect beam stability. In this paper we report the simulation results of monopole High Order Modes (HOM) spectrum in the 1.3 GHz accelerating structure. Optimum parameters of the HOM feedthrough are suggested for minimizing RF losses on the HOM antenna tip and for preserving an efficiency of monopole HOMs damping simultaneously.

Poster MOPLR006 [0.647 MB]

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MOPLR009

X-Band Travelling Wave Accelerating Section R&D for HTF

electron, operation, cavity, vacuum

152

K. Jin
USTC/NSRL, Hefei, Anhui, People's Republic of China

Hefei Light Source (HLS) was mainly composed of an 800 MeV electron storage ring and an 800MeV-1GeV constant-gradient accelerator in NSRL. The new Linac with Full Energy Injection and the Top-up Injection scheme has been developed successfully. And the other functioning as X Ray Free Electron Laser test facility has been considered. In the project, in order to compress the bunch length and to achieve the beam energy distribution linearization. A 15MeV, operation frequency 11.424GHz traveling wave accelerating section as harmonic compensation is being developed. In this paper, X Ray Free Electron Laser Hefei Test Facility (HTF) is introduce briefly. And the R&D of the x-band accelerating section with collinear load are presented in detail.

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MOPLR030

Electromagnetic Design of a Superconducting Twin Axis Cavity

cavity, HOM, linac, dipole

203

S.U. De Silva, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA
A. Hutton, F. Marhauser, H. Park
JLab, Newport News, Virginia, USA

The twin-axis cavity is a new kind of rf superconducting cavity that consists of two parallel beam pipes, which can accelerate or decelerate two spatially separated beams in the same cavity. This configuration is particularly effective for high-current beams with low-energy electrons that will be used for bunched beam cooling of high-energy protons or ions. The new cavity geometry was designed to create a uniform accelerating or decelerating fields for both beams by utilizing a TM110 dipole mode. This paper presents the design rf optimization of a 1497 MHz twin-axis single-cell cavity, which is currently under fabrication.

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MOPLR048

Fabrication and Testing of a Novel S-Band Backward Travelling Wave Accelerating Structure for Proton Therapy Linacs

linac, vacuum, proton, accelerating-gradient

237

S. Benedetti, T. Argyropoulos, C. Blanch Gutiérrez, N. Catalán Lasheras, A. Degiovanni, D. Esperante Pereira, M. Garlaschè, J. Giner Navarro, A. Grudiev, G. McMonagle, A. Solodko, M.A. Timmins, R. Wegner, B.J. Woolley, W. Wuensch
CERN, Geneva, Switzerland
D. Esperante Pereira
IFIC, Valencia, Spain

Compact and more affordable, facilities for proton therapy are now entering the market of commercial medical accelerators. At CERN, a joint collaboration between CLIC and TERA Foundation led to the design, fabrication and testing of a high gradient accelerating structure prototype, capable of halving the length of state-of-art light ion therapy linacs. This paper focuses on the mechanical design, fabrication and testing of a first prototype. CLIC standardized bead-pull measurement setup was used, leading to a quick and successful tuning of the prototype. The high power tests will soon start in order to prove that the structure can withstand a very high accelerating gradient while suffering no more than 10^-6 breakdown per pulse per meter (bpp/m), resulting in less than one breakdown per treatment session.

Poster MOPLR048 [2.804 MB]

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MOPLR053

Operating Status of Injector II RFQ for C-ADS Project

rfq, cavity, impedance, scattering

254

L.P. Sun, Y. He, C.X. Li, L. Lu, A. Shi, L.B. Shi, W.B. Wang, X.B. Xu, Z.L. Zhang, H.W. Zhao
IMP/CAS, Lanzhou, People's Republic of China

The Radio Frequency Quadrupole system has been designed and constructed for C-ADS (Chinese Accelerator Driven System) Injector II in Institute of Modern Physics (IMP), Chinese Academy of Sciences, which has been running for more than one year until now. It is a quadrilateral four-vane resonator with two equal couplers operating in CW mode. In the paper, RF system upgrade will be presented in detail，especially the two-port configuration was introduced and the conditioning based on two new sets of solid-state amplifier instead of the original tetrodes power source due to system hardware upgrade are described in the paper.
RFQ, solid-state amplifier, two-port configuration, coupler

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MOPLR067

First High Power Tests at the 325 MHz RF Test Stand at GSI

cavity, linac, rfq, klystron

287

G. Schreiber, E. Plechov, J. Salvatore, B. Schlitt, A. Schnase, M. Vossberg
GSI, Darmstadt, Germany

A dedicated RF test stand for testing RF components and accelerating structures at 325 MHz has been put into operation at GSI. It allows testing the klystrons and circulators as well as the RFQ and the CH-acceleration cavities for the planned FAIR proton linac (p-Linac) and further cavity projects. The system integration has been completed and first high power tests with the CH prototype cavity were successfully performed. The operation parameters are 2 Hz repetition rate and 200 microseconds pulse length. Investigations on the critical path from wave guide to coaxial high power cavity coupler have been made. Performance measurements of the klystron, circulator and directional couplers with up to 2.8 MW on dummy load and the following conditioning process of the CH-prototype cavity with its coupled RF structures will be presented. Additionally the results of the conditioning of a ladder RFQ prototype are shown.

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TUOP05

First Experiments at the CW-Operated RFQ for Intense Proton Beams

rfq, ion, operation, experiment

394

P.P. Schneider, D. Born, M. Droba, C. Lorey, O. Meusel, D. Noll, H. Podlech, A. Schempp, B. Thomas, C. Wagner
IAP, Frankfurt am Main, Germany

This contribution describes the first experiments with the cw-operated RFQ*, which is designed to accelerate protons from 120keV to 700keV for the FRANZ-Project**. The commissioning is done using the RF and ion beam scrubbing technique. In the first phase, the acceptance of the RFQ is scanned and the performance of the RFQ without space-charge effects is evaluated with a 2mA proton beam. The second phase will increase the beam current up to 50mA and a third phase with a machine upgrade for a beam current of up to 200mA is planned. The configuration of a high-current RFQ***, transporting beam current increasing from 2mA with no space-charge forces to a beam with high space-charge effects gives an unique insight in the beam optics of the space-charge effects. The measurements are done with a slit-grid emittance scanner for the transversal phase-space, a faraday cup for the transmitted current and a momentum spectrometer to measure the energy spread. The results set the basis for later experiments on variations of the beam current and the future coupling of the RFQ with an IH-structure****.
* Bechtold, A., et al., MOP001, LINAC08
** Meusel, O., et al., MO3A03, LINAC12
*** Vossberg, M., et al., WEPFI009, IPAC13
**** Heilmann, M., et al., THPWO017, IPAC13

Slides TUOP05 [2.435 MB]

Poster TUOP05 [4.550 MB]

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TUPRC017

Field Flatness and Frequency Tuning of the CLARA High Repetition Rate Photoinjector

cavity, cathode, FEL, gun

452

L.S. Cowie, P. Goudket, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
T.J. Jones
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
B. Keune
RI Research Instruments GmbH, Bergisch Gladbach, Germany

The High Repetition Rate Photoinjector, designed for the CLARA FEL at Daresbury Laboratory, was tuned at the manufacturers for both field flatness and frequency. Due to the high average power in the cavity of 6.8 kW the cavity requires significant cooling, achieved by water channels in the cavity body. These channels prohibit the use of tuning studs to tune the cavity. The cavity was tuned by taking pre-braze clamped low power RF measurements and using the data to trim the cavity cells to the optimum length for both field flatness and frequency. The optimum field flatness is 100% and the design frequency is 2998.5 MHz. Both cells were trimmed in 3 stages, resulting in a post-braze frequency of 2998.51 MHz and field flatness of 98%.

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TUPLR005

Development of 6 MeV European S-band Side-Coupled Industrial Electron Linear Accelerator at RTX & KAERI

electron, linac, target, gun

478

P. Buaphad, S.C. Cha
KAERI, Jeongeup-si, Republic of Korea
P. Buaphad
University of Science and Technology of Korea (UST), Daejeon, Republic of Korea
P. Buaphad
RTX, Daejeon, Republic of Korea
Y. Kim
ISU, Pocatello, Idaho, USA

There are growing demands on low energy electron linear accelerator (linac) for industrial applications. Most of industrial electron linacs require a compact structure and limited undesirable neutron production to avoid huge lead shielding. Radiation Technology eXcellence (RTX) and Korea Atomic Energy Research Institute (KAERI) have developed a 6 MeV compact side-coupled linac by using 2998 MHz European S-band RF technology to meet those requirements. To design the linac structure, the 3D CST MICROWAVE STUDIO (CST-MWS) was used for various electromagnetic simulations, and ASTRA code was used for particle beam dynamics simulations. After various optimizations, the shunt impedance of 61 MΩ/m is obtained at 2998.38 MHz. With a peak RF power of 2.2 MW and a 47 cm-long structure, electron beam with a peak current of 150 mA can be accelerated from 25 keV to 6 MeV. For the industrial linac, the electron beam spotsize at an X-ray target, located 5 cm downstream of the linac structure exit should be smaller than 2 mm (FW). In addition, it can supply an X-ray dose rate of 8 Gy/min at 1 m after the X-ray target. In this paper, we describe the design concepts and optimization of the 2998 MHz side-coupled industrial linac structure.

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TUPLR050

Design of 4-vane RFQ with Magnetic Coupling Windows for Nuclotron Injector Lu-20

rfq, ion, Windows, linac

575

V.A. Koshelev, G. Kropachev, T. Kulevoy, D.A. Liakin, A.S. Plastun
ITEP, Moscow, Russia
A.V. Butenko
JINR, Dubna, Moscow Region, Russia
T. Kulevoy, S.M. Polozov
MEPhI, Moscow, Russia
S.V. Vinogradov
MIPT, Dolgoprudniy, Moscow Region, Russia

Alvarez-type linac LU-20 is used as Nuclotron injector. In the framework of NICA project the high voltage electrostatic pre-injector for LU-20 has been replaced by RFQ linac. The RFQ was designed by the team of ITEP and MEPhI (Moscow, Russia) and was manufactured in VNIITF (Sneginsk, Russia). The engineering design of the 4-vane RFQ linac with magnetic coupling windows and details of its manufacturing are presented and discussed.

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TUPLR058

Progress of a 162.5 MHz High-Current RFQ With Coupling Windows

rfq, Windows, cavity, simulation

589

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

Funding: Supported by National Basic Research Program of China(2014CB845503)
A 162.5 MHz, four-vane RFQ with magnetic coupling windows has been designed by the RFQ group of Peking University. Clear frequency separation of the resonant modes and smaller transverse dimension are the advantages of the window-type RFQ. The electromagnetic simulations have shown that the average power loss of this 1.809 m long RFQ is about 50 kW in continuous wave mode. Consequently, a water cooling system was designed via the multi-physics analysis. The mechanical design and assembling technology were also presented in this paper.

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TUPLR060

RF Design of the Nuclotron-NICA 145.2 MHz RFQ

rfq, Windows, dipole, simulation

595

A.S. Plastun, V. Andreev, V.A. Koshelev, T. Kulevoy, V.G. Kuzmichev, D.A. Liakin, A. Sitnikov
ITEP, Moscow, Russia
A.V. Butenko
JINR, Dubna, Moscow Region, Russia

ITEP has designed the Radio-Frequency Quadrupole (RFQ) linac for the JINR NICA Complex (Dubna, Russia) to provide ion beams (q/A ≥ 0.3) with energy of 156 keV/u for further acceleration by existing Alvarez-type linac. The RFQ is based on a 4-vane structure with magnetic coupling windows in order to avoid a risk of excitation of dipole field components inherent in a conventional 4-vane resonator. The paper presents results of the radio-frequency (RF) design and capabilities used for coarse and fine tuning of the field distribution and resonant frequency during manufacturing and finalizing of the RFQ.

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WE1A05

HIE-ISOLDE SC Linac Progress and Commissioning in 2016

cryomodule, cavity, linac, cryogenics

663

W. Venturini Delsolaro, E. Bravin, N. Delruelle, M. Elias, E. Fadakis, J.A. Ferreira Somoza, F. Formenti, M.A. Fraser, J. Gayde, N. Guillotin, Y. Kadi, G. Kautzmann, T. Koettig, Y. Leclercq, M. Martino, M. Mician, A. Miyazaki, E. Montesinos, V. Parma, J.A. Rodriguez, S. Sadovich, E. Siesling, D. Smekens, M. Therasse, L. Valdarno, D. Valuch, G. Vandoni, U. Wagner, P. Zhang
CERN, Geneva, Switzerland

The HIE-ISOLDE project (High Intensity and Energy ISOLDE) reached an important milestone in October 2015 when the first physics run was carried out with radioactive Zn beams at 4 MV/m. This is a first stage in the upgrade of the REX post-accelerator, whereby the energy of the radioactive ion beams was increased from 3 to 4.3 MeV per nucleon. The facility will ultimately be equipped with four high-beta cryomodules that will accelerate the beams up to 10 MeV per nucleon for the heaviest isotopes available at ISOLDE. The first cryomodule of the new linac, hosting five superconducting cavities and one solenoid, was commissioned in summer 2015, while the second one was being assembled in clean room. The new high-energy beam transfer lines were installed and commissioned in the same lapse of time. Commissioning with two cryomodules is planned for Summer 2016 to prepare for a physics run at 5.5 MeV/u in the second half of the year. This contribution will focus on the results of the commissioning and operation of the SC linac in 2015. Plans for the second phase of the HIE-ISOLDE project will be highlighted.

Slides WE1A05 [4.194 MB]

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TH1A04

SARAF 4-Rods RFQ RF Power Line Splitting Design and Test

rfq, operation, proton, vacuum

693

J. Rodnizki, D. Hirschmann, Z. Horvitz, B. Kaizer, A. Perry, L. Weissman
Soreq NRC, Yavne, Israel

In the last years the SARAF 176 MHz 3.8 m long 4-rod RFQ accelerates routinely 2-4 mA CW proton beams to 1.5 MeV for basic studies in physics. However, it has not been successful in running CW deuteron beam for long periods. The findings imply that the RF coupler is the bottle neck to reach 250 kW CW dissipated power, equivalent to 65 kV inter-rod voltage, required to run the CW deuteron beam. A new design that splits the RFQ power between two couplers was built and commissioned successfully. A 3dB splitter and two new RF couplers were installed. The RF couplers improved design allows better brazing methods, vacuum properties and RF sealing. This design is innovative from two points of view: (a) implementation of two synchronized couplers located in two separated RF cells in a 4-rod RFQ. (b) The ability to run the RFQ in 200-250 kW to accelerate a 5 mA CW deuteron beam by 2.6 MV required for the new modulation design for 1.3 MeV/u. To our knowledge, SARAF RFQ will be the first 4-rod RFQ capable of running a CW deuteron beam at these power densities. This work may contribute to other 4-rod RFQ projects which intend to run CW beams in high dissipation power, like FRANZ and MYRRHA.

Slides TH1A04 [6.109 MB]

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TH2A03

Complete Transverse 4D Beam Characterization for Ions Beams at Energies of Few MeV/u

emittance, quadrupole, ion, vacuum

720

M.T. Maier, X. Du, P. Gerhard, L. Groening, S. Mickat, H. Vormann
GSI, Darmstadt, Germany

Measurement of the ion beam rms-emittances is done through determination of the second order beam moments. For time being the moments quantifying the amount of inter-plane coupling, as <xy'> for instance, have been accessible to measurements just for very special cases of ions at energies below 200 keV/u using pepperpots. This talk presents successful measurements of all inter-plane coupling moments at 1 to 11 MeV/u. From first principles the used methods are applicable at all ion energies. The first campaign applied skewed quadrupoles in combination with a regular slit/grid emittance measurement device. The second campaign used a rotatable slit/grid device in combination with regular quadrupoles.

Slides TH2A03 [17.343 MB]

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THPLR011

Traveling Wave Accelerating Structure Power Input Calculation With Equivalent Circuit Method

impedance, operation, interface, resonance

864

S.V. Matsievskiy, V.I. Kaminskiy
MEPhI, Moscow, Russia

Nowadays linac accelerating RF systems design is usually done by the finite difference method. It provides high accuracy of calculations and freedom in topology choosing, but may draw considerable amounts of computer resources with long calculation times. Alternative to this method, equivalent circuit method exists. The basic idea of this method is to build a lumped element circuit, which with certain approximation acts as an original accelerating cell. It drastically reduces the number of equations to solve. This method is long known but usually only used for the particular accelerating structures when speed of calculation is a key-factor. This paper describes an attempt to create more universal and user-friendly software application for calculating electrical field distribution in accelerating structures, provides mathematical equations this software is based on. The resulting application may be used for preliminary calculations of acceleration structures and help to determine cells electrodynamic parameters reducing overall design time.

Poster THPLR011 [0.789 MB]

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THPLR018

HOM Suppression Improvement for Mass Production of EXFEL Cavities at RI

cavity, HOM, damping, linac

879

A.A. Sulimov, J.H. Thie
DESY, Hamburg, Germany
M. Pekeler, D. Trompetter
RI Research Instruments GmbH, Bergisch Gladbach, Germany

During cold RF tests of the European XFEL (EXFEL) cavities at DESY it was observed that the damping of the second monopole mode (TM011) showed the largest variation, which was sometimes up to 2-3 times lower than the originally allowed limit. It was concluded that this TM011-damping degradation was caused by cavity geometry deviation within the specified mechanical tolerances. The particular influence of different mechanical parameters was analyzed and additional RF measurements were carried out to find the most critical geometry parameters. Stability of the equator welding and regularity of chemical treatment were investigated for different cavity cells. In spite of the high fabrication rate during EXFEL cavity mass production the TM011 suppression was improved to an acceptable level.

Poster THPLR018 [0.378 MB]

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THPLR040

First Vertical Test of Superconducting QWR Prototype at RIKEN

ion, cryomodule, acceleration, multipactoring

939

K. Yamada, O. Kamigaito, K. Ozeki, N. Sakamoto, K. Suda, Y. Watanabe
RIKEN Nishina Center, Wako, Japan
E. Kako, H. Nakai, K. Umemori
KEK, Ibaraki, Japan
A. Miyamoto, K. Sennyu, T. Yanagisawa
MHI-MS, Kobe, Japan

Development of a superconducting quarter-wavelength resonator (SC-QWR) was started at RIKEN Nishina Center to realize a low-velocity part of high-intensity ion linac. First prototype of the SC-QWR, frequency of which is 75.5 MHz, is fabricating now*. Preparation of its partial components such as outer conductor, stem, bottom plate, and top plate was almost completed, and we are now studying a low-power RF property by clamping the every components as an assembly to obtain data for frequency tuning. After the adjustment of geometry of components and welding them, surface treatment by buffered chemical polishing and high-pressure rinsing will be performed in the summer. Preparation of vertical test for the SC-QWR is also in progress at KEK. The first result of vertical test for the prototype of SC-QWR will be presented in this contribution. This work was funded by the ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan).
* N. Sakamoto et al., Proceedings of SRF2015, WEBA06.

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THPLR060

Experience with the Conditioning of Linac4 RF Cavities

cavity, vacuum, linac, DTL

985

S. Papadopoulos, F. Gerigk, J.-M. Giguet, J. Hansen, J. Marques Balula, A.I. Michet, S. Ramberger, N. Thaus, R. Wegner
CERN, Geneva, Switzerland

Linac4, the future H⁻ injector of the PS complex at CERN has reached the hardware and beam commissioning phase. This paper summarizes the experience gained in RF conditioning of the DTL, CCDTL and PIMS cavities. The behaviour in conditioning of these cavities strongly depends on the cavity type and assembly conditions. Examples of conditioning history and vacuum measurements before, during and after conditioning are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR060

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THPLR066

Preparation and Installation of IFMIF-EVEDA RFQ at Rokkasho Site

rfq, alignment, cavity, vacuum

1005

E. Fagotti, L. Antoniazzi, A. Baldo, A. Battistello, P. Bottin, L. Ferrari, M.G. Giacchini, F. Grespan, M. Montis, A. Pisent, D. Scarpa
INFN/LNL, Legnaro (PD), Italy
D. Agguiaro, A.G. Colombo, A. Pepato, L. Ramina
INFN- Sez. di Padova, Padova, Italy
F. Borotto Dalla Vecchia, G. Dughera, G. Giraudo, E.A. Macri, P. Mereu, R. Panero
INFN-Torino, Torino, Italy

The IFMIF-EVEDA RFQ is composed of 18 modules for a total length of 9.8 m and is designed to accelerate the 125 mA D⁺ beam up to 5 MeV at the frequency of 175 MHz. The RFQ is subdivided into three Super-Modules of six modules each. The Super-Modules were pre-assembled, aligned and vacuum tested at INFN-LNL and then shipped to Rokkasho (Japan). At Rokkasho site a series of test were performed in order to verify the effect of the shipment on the cavity. The assembly debug, shipment equipment and the sequence of operations are described in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR066

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THPLR067

Series Production of the RF Power Distribution for the European XFEL

cavity, klystron, cryogenics, status

1008

S. Choroba, V.V. Katalev
DESY, Hamburg, Germany
E.M. Apostolov
Technical University of Sofia, Sofia, Bulgaria

The RF power distribution for the European XFEL allows for individual RF power for the 808 superconducting cavities of the European XFEL. It consists of a number of elements, not only waveguide components, but also girders, cables or cooling systems. The production of the RF distribution consists of several tasks. In order to deal with the schedule of the entire project a detailed planning, organization and monitoring of the series production of the RF power distribution was required. This paper describes the RF power distribution layout and the series production process.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR067

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THPLR069

Quality Factor Measurement Method Using Multi Decay Time Constants on Cavity

cavity, pick-up, superconducting-cavity, cryomodule

1011

J.W. Kim, H. Kim
IBS, Daejeon, Republic of Korea

Quality factor measurement method using multi decay time constants on superconducting cavity is suggested. In most cases of vertical test, one decay time constant is measured around critical coupling and coupling constants are measured using forward and reflected rf power to get intrinsic quality factor. We use multi decay time constants method to measure the quality factor, which uses three decay time constants. Two more switches before and after the cavity are added to the measurement system. Decay time constants are measured by switching off the rf power switch in front of rf source, the forward power switch in front of input power coupler, and then the pickup power switch behind the pickup coupler, respectively, at the same power of steady state.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR069

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