LINAC2014 - List of Keywords (vacuum)

Paper	Title	Other Keywords	Page
MOPP094	Latest Improvements of the SPring-8 Linac for High Reliability	linac, operation, electron, injection	276
	S. Suzuki, H. Dewa, H. Hanaki, T. Kobayashi, T. Magome, A. Mizuno, T. Taniuchi, K. Yanagida JASRI/SPring-8, Hyogo-ken, Japan T. Asaka RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	In order to perform stable injection to the 8GeV SPring-8 storage ring, which is performing the top-up operation, the high reliability of the linac has been advanced as follows: For reduction of phase variations caused by the waveguide deformation due to the variations of temperature or atmospheric pressure, the waveguide circuit of SF6 enclosure type, which fed RF powers to the bunching section, was replaced with that of vacuum type. And S-band 10MW circulators and isolators of vacuum type were adopted for the first time in the world. The timing system was improved so that the interval time of the beam injection into the 8GeV booster synchrotron and the 1.5 GeV NewSUBARU storage ring has been reduced to 1 sec from 15 seconds, respectively, even in the top-up operation of both storage rings. As a result, the stored current by the top-up operation were further stabilized. The stored current of the NewSUBARU storage ring was stabilized to 0.18% from 0.31%. The electron gun cathode assembly has been developed to reduce the dark emission from a grid plate by the double grid method and the electrolytic polishing.

MOPP115	Plasma Processing of Nb Surfaces for SRF Cavities	plasma, SRF, cavity, accelerating-gradient	323
	P.V. Tyagi, M. Doleans, S.-H. Kim ORNL, Oak Ridge, Tennessee, USA R. Afanador, C.J. McMahan ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: This work is supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. Field emission is one of the most critical issues to achieve high performances of niobium (Nb) superconducting radio frequency (SRF) cavities. Field emission is mainly related to contaminants present at top surface of SRF cavities that act as electron emitters at high gradient operation and limit the cavity accelerating gradient. An R&D program at the Spallation Neutron Source (SNS) is in place* aiming to develop an in-situ plasma processing technique to remove some of the residual contaminants from inner surfaces of Nb cavities and improve their performance. The plasma processing R&D has first concentrated on removing hydrocarbon contamination from top surface of SRF cavities. Results from the surface studies on plasma processed Nb samples will be presented in this article and showed the removal of hydrocarbons from Nb surfaces as well as improvement of the surface workfuntion (WF). *M. Doleans et al. “Plasma processing R&D for the SNS superconducting linac RF cavities” Proceedings of 2013 SRF workshop, Paris, France
	Slides MOPP115 [1.405 MB]

MOPP118	C-Band Load Development for the High Power Test of the SwissFEL RF Pulse Compressor	impedance, cavity, klystron, coupling	329
	A. Citterio, J. Stettler, R. Zennaro PSI, Villigen PSI, Switzerland
	The SwissFEL C-band Linac will have 26 RF modules, each one consisting of a solid-state modulator and a 50 MW klystron that feeds a pulse compressor and four two meters long accelerating structures. The pulse compressor is of the Barrel Open Cavity type (BOC). A first prototype was successfully produced and high-power tested, reaching for full power klystron operation a peak power of 300 MW. For testing this BOC at maximum RF power, a broadband load was designed and built, based on a ridge waveguide design and high permeability stainless steel. Based on the experience gained at CERN for CLIC X-band high power loads, the RF design of the load was optimized to ensure high losses for a quite large range of magnetic steels. Test pieces were realized in three different magnetic steels to choose the best suited material commercially available. This paper reports about the RF design, material study, production and impressive high power results of this C-band load.

MOPP119	Measurements and High Power Test of the First C-band Accelerating Structure for SwissFEL	operation, FEL, klystron, linac	333
	R. Zennaro, J. Alex, A. Citterio, J.-Y. Raguin PSI, Villigen PSI, Switzerland
	The SwissFEL project is based on a 5.8 GeV C-band Linac which is composed of 10⁴ accelerating structures with a length of 2 m each. Due to the absence of dimple tuning no local frequency correction is possible and hence ultra-precise machining is required. The paper reports on both low level and high power RF test of the first nominal structure produced. The required mechanical precision has been reached and the structure has been successfully power tested to a gradient larger than 50 MV/m, well above the nominal level of 28 MV/m. The measured dark current and break down rates are well in the specifications.

MOPP124	Development of a 3 MeV Prototype RFQ Structure for High Intensity Proton Linac for ISNS	rfq, ion, operation, proton	345
	S.C. Joshi, A. Chaturvedi, S.K. Chauhan, K.K. Das, G.V. Kane, S.V. Kokil, B. Oraon, S. Raghvendra, N.K. Sharma RRCAT, Indore (M.P.), India
	Raja Ramanna Centre for Advanced Technology (RRCAT) has taken up a program on R&D activities of a 1 GeV, high intensity superconducting proton linac for a spallation neutron source. A 3 MeV Radio Frequency Quadrupole (RFQ) will be used as front end of the pulsed proton linac. A full scale prototype RFQ structure has been designed and fabricated to validate the physics design and manufacturing procedures. The total of 3.46 meter has been divided in three segments for ease in machining. The fabricated RFQ structure has been assembled for low power RF characterization. The RFQ frequency and field tuning exercise is being carried out using 48 stub tuners. The paper will also present the engineering design aspects and fabrication issues for the full scale RFQ structure.

MOPP134	Superconducting Accelerating Cavity Pressure Sensitivity Analysis and Stiffening	cavity, proton, simulation, linac	373
	J. Rodnizki, Y. Ben Aliz, A. Grin, Z. Horvitz, A. Perry, L. Weissman Soreq NRC, Yavne, Israel G.K. Davis JLab, Newport News, Virginia, USA J.R. Delayen ODU, Norfolk, Virginia, USA
	The SARAF Prototype Superconducting Module (PSM) houses six 176 MHz Half Wave Resonators(HWR). The PSM accelerates protons and deuterons from 1.5 MeV/u to 4 and 5.6 MeV. The HWRs are highly sensitive to the coolant liquid Helium pressure fluctuations which limit the available beam power to 2kW per cavity out of 4kW RF amplifier and coupler and so might limit the available beam current to 2mA depending on the output energy. The flat shape of the cavity along the beam line in the area of the high electric field generates the high sensitivity of the Eigen mode frequency to helium pressure. The evaluated cavity sensitivity is full consistent with the measured values. It was explored that the tuning system (the fog structure) has a significant contribution to the cavity sensitivity. By using ribs or by modifying the rigidity of the fog we may reduce the HWR sensitivity by a factor of 3. This analysis is applied to study the stresses on the cavity during cool down and warm up to avoid plastic deformation as the Niobium yield is an order of magnitude lower in room temperature.

TUIOB04	DTL Construction Status of CSNS Project	DTL, linac, neutron, ion	423
	H.C. Liu, S. Fu, J. Peng, S. Wang IHEP, Beijing, People's Republic of China
	Linac of Chinese Spallation Neutron Source (CSNS) project is under construction. The ion source is tested and good performance of beam current is obtained. The low level RF tuning is underway of the RFQ and assembling of DTL will start soon. Not only the construction of hardware, but some commissioning software packages have been developed and tested.
	Slides TUIOB04 [4.772 MB]

TUIOC01	Large Scale Testing of SRF Cavities and Modules	cryomodule, cavity, software, laser	426
	J. Świerbleski IFJ-PAN, Kraków, Poland
	Series production of SRF cavities, s.c. quadrupole packages and accelerator modules for the European XFEL is in full swing. Mid 2014 approx. 400 cavities will be tested, the testing of quadrupoles will be almost finished, and regular module testing will be established. Thus the talk should emphasize the quasi industrial testing of these components, of course including a good overview about the used somewhat unique AMTF infrastructure.
	Slides TUIOC01 [3.094 MB]

TUPP040	Preliminary Functional Analysis of ESS Superconducting Radio-Frequency Linac	cryomodule, controls, interface, SRF	522
	C. Darve, N. Elias, J. Fydrych, D.P. Piso ESS, Lund, Sweden
	The European Spallation Source (ESS) is one of Europe's largest planned research infrastructures. The collaborative project is funded by a collaboration of 17 European countries and is under design and construction in Lund, Sweden. Three families of Superconducting Radio-Frequency (SRF) cavities are being prototyped, counting the spoke resonators with a geometric beta of 0.5, medium-beta elliptical cavities (βg=0.67) and high-beta elliptical cavities (bg=0.86). The 5 MW, 2.86 ms long pulse proton accelerator has a repetition frequency of 14 Hz (4 % duty cycle), and a beam current of 62.5 mA. The cavities and power couplers are assembled into cryomodules, which are operating using RF sources, cryogenic and water coolings. This document describes the process of the ESS SRF cryomodule operation while refereeing to operational modes.

TUPP049	Test Stand for 325 MHz Power Couplers	cavity, multipactoring, pick-up, high-voltage	538
	S. Kazakov, B.M. Hanna, T.N. Khabiboulline, V. Poloubotko, O.V. Pronitchev, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	325 MHz superconducting Single Spoke resonators (SSR1) will be utilized in the Project X Injector Experiment (PXIE). Developed in Fermilab the main power coupler will be supply 2kW CW RF power to each cavity. Fermilab developed and designed the special test stand where the couplers will be tested up to 10 kW and design properties be confirmed. This paper describes the design of the coupler test stand and preliminary results of the tests.

TUPP055	Progress on Euclid SRF Conical Half-Wave Resonator Project	cavity, niobium, SRF, proton	547
	E.N. Zaplatin FZJ, Jülich, Germany T.L. Grimm Niowave, Inc., Lansing, Michigan, USA A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: This Work is supported by the DOE SBIR Program, contract # DE-SC0006302. Euclid conical Half-Wave Resonator (cHWR) project develops 162.5 MHz β=v/c=0.11 accelerator structure for the high-intensity proton accelerator complex proposed at Fermi National Accelerator Laboratory. The main idea of this project is to provide a self-compensation cavity design together with its helium vessel to minimize the resonant frequency dependence on external loads. A unique cavity side-tuning option is also under development. Niowave, Inc. proposed a complete cavity production procedure including preparation of technical drawings, processing steps and resonator high-gradient tests to demonstrate such possibility for the private company. Here we present the procedure of the cavity and helium vessel fabrication, cavity preparation and initial experimental results.

TUPP057	In Situ Measurement of Mechanical Vibrations of a 4-Rod RFQ at GSI	laser, rfq, operation, quadrupole	553
	P. Gerhard, L. Groening, K.-O. Voss GSI, Darmstadt, Germany
	A new 4-rod CW Radio Frequency Quadrupole was commissioned at the high charge state injector HLI at the UNILAC in 2009. It is in operation since 2010. At high rf amplitudes strong modulations of the rf reflection emerge, with a modulation frequency of approximately 500 Hz. They are attributed to mechanical oscillations of the rods, excited by the rf pulse. The high fraction of reflected rf power severely limits the pulse length and rf amplitude achievable. As these modulations could only be seen during the rf pulse by means of rf measurements, a direct observation of the mechanical vibrations was desirable. Such measurements have been conducted using a commercial laser vibrometer, allowing for the investigation of the mechanical behavior of the RFQ independent of the presence of rf power. After a short introduction of the method, the results will be presented and compared with rf measurements and simulations. : P. Gerhard et al., “Experience with a 4–Rod CW RFQ”, LINAC’12, Sept. 2012, Tel Aviv, THPB035

TUPP071	Vortex-Penetration Field at a Groove with a Depth Smaller than the Penetration Depth	cavity, experiment, framework	590
	T. Kubo KEK, Ibaraki, Japan
	Analytical models of the magnetic field enhancement at pits were presented at SRF2013 last year. In this presentation, I will show updated models. proceedings of SRF 2013, Paris, France (2013), p. 430

TUPP077	High Precision Manufacturing for LINAC's	linac, extraction, controls, laser	603
	F.M. Mirapeix, J. Añel HTS, Mendaro, Spain J. Amores, J. Presa, A. Urzainki DMP, Mendaro, Spain
	A big effort in R&D focused to the LINAC devices together with the know-how already deployed through emblematic projects places DMP in the state of the art of the extreme precision mechanics. This mechanic culture makes of DMP a natural partner in early stages of design or driver of a comprehensive solution, optimizing industrial risks, quality and due date. Surface roughness below 1 nanometer, figure errors better than 50 nanometers in OFE copper enhances lifetime and performance of many devices for LINAC's. Research in joining techniques and combining several alternative technologies to traditional machining improves figure stability and makes complex cooling systems possible.

TUPP084	Surface Treatment Facilities for SCRF Cavities at RISP	cavity, superconducting-cavity, niobium, superconducting-RF	619
	J. Joo, D. Jeon, M.J. Joung, Y. Jung, H.J. Kim, M. Lee IBS, Daejeon, Republic of Korea
	Rare Isotope Science Project is engaged in the fabrication of four types of superconducting RF cavities. The surface treatment is one of the important processes of superconducting RF cavity fabrication. New superconducting RF cavity processing systems have been designed and developed for the etching of niobium in buffered chemical polish at RISP. The safety precautions used in protecting the operator from the acids used in the etchant and from the fumes given of during the process are discussed. All of the new hardware will be located in RISP Munji Superconducting Cavity Test Facility.

TUPP085	RAON Cryomodule Design for QWR, HWR, SSR1 and SSR2	cryomodule, simulation, linac, cavity	622
	W.K. Kim, H. Kim, H.J. Kim, Y. Kim, M. Lee, G.-T. Park IBS, Daejeon, Republic of Korea
	The accelerator called RAON which will be built in Korea has four kinds of superconducting cavities such as QWR, HWR, SSR1 and SSR2, operating at 2 K and 4.5 K [1]. The current status of design for the QWR, HWR, SSR1 and SSR2 cryomodules are reported. The issues included in the paper are thermal and structural design results of the components such as supports and thermal shield in the cryomodules. The cryomodule hosts the superconducting cavities in high vacuum and thermally insulated environment in order to maintain the operating temperature of superconducting cavities. It also keeps the cavities in a good alignment to the beam line. It has an interface for supplying RF power to cavities between cold and warm components. The whole configuration of the integrated system is also presented. This paper presents the detailed design of the cryomodule.

TUPP088	The Fabrication of the β=0.12 HWR at RISP	niobium, cavity, target, electron	628
	G.-T. Park, H.J. Cha, Y. Jung, H. Kim, W.K. Kim IBS, Daejeon, Republic of Korea
	At RISP, the superconducting cavities have been developed to construct RAON, the heavy ion accelerator. Among the cavities, the fabrication of the QWR (Quarter wave resonator) and the HWR (Half wave resonator)are complete. The detailed fabrication processes including material inspection, forming, the electron beam welding, and the clamp up test are described.

TUPP093	The Couplers for the IFMIF-EVEDA RFQ High Power Test Stand at LNL: Design, Construction and Operation	cavity, coupling, rfq, simulation	643
	E. Fagotti, L. Antoniazzi, M.G. Giacchini, F. Grespan, M. Montis, A. Palmieri, A. Pisent, C. R. Roncolato INFN/LNL, Legnaro (PD), Italy
	In order to assess the critical aspects of the IFMIF-EVEDA RFQ construction procedure and operation, it was decided to perform a High Power Test of a subset of the RFQ consisting in its last 550 mm three modules (out of 18) plus a Prototype Module, 390 mm long, used as RF plug. These modules are going to be tested at full power in CW of INFN LNL Labs, in the so-called RFQ High Power Test Stand. For such a purpose, a RF tube-based amplifier capable of 220 kW CW output power at the operational frequency of 175 MHz was purchased from an Italian company. A critical component of this test is the RF power coupler. Therefore INFN-LNL developed a design of two identical water-cooled loop antenna couplers, built with OFE copper and vacuum sealed with a commercially available 6”1/8 Alumina planar window. These couplers were tested separately on an aluminium coupling cavity. In particular one of them acts as a power feeder, while the other one, connected with a 200 kW water-cooled load, acts as a receiver. In this paper, the main aspects of the design, construction and tests performed on the couplers and coupling cavity will be described.

TUPP095	High-Power Test Results of the RFQ III in J-PARC Linac	rfq, operation, cavity, ion	649
	T. Morishita, K. Hasegawa, K. Hirano, Y. Kondo, H. Oguri, S. Yamazaki JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan T. Hori JAEA, Ibaraki-ken, Japan F. Naito, T. Sugimura, A. Takagi KEK, Ibaraki, Japan
	The J-PARC accelerator comprises an injector linac, a 3-GeV Rapid-Cycling Synchrotron and a 50-GeV Main Ring. The beam energy of the linac has been upgraded from 181MeV to 400MeV in 2013. For the beam current upgrade, the new frontend (RF ion source, RFQ, chopping system) installation is scheduled in summer 2014 for 1MW operation at RCS. The RFQ III, which is designed for 50mA beam acceleration from 0.05MeV to 3MeV, has been fabricated and the high-power test has started at April 2013 at the test station in the J-PARC. The test station consists of the ion source, the LEBT, the RFQ, and the diagnostics devices. The nominal RF power and RF duty of the RFQ III are 380kW and 3%(0.6ms and 50Hz), respectively. The high-power conditioning reached to the 120% of the nominal power with 1.5% (0.6ms, 25Hz) RF duty within 24 hours. Then, we performed the beam operation at the test station and measured beam parameters after the RFQ III. The results of the high-power conditioning and the stability of the RFQ operation with beam will be discussed.

TUPP122	Roughness Tolerances in the Undulator Vacuum Chamber of LCLS-II	impedance, undulator, wakefield, FEL	708
	K.L.F. Bane, G.V. Stupakov SLAC, Menlo Park, California, USA
	Funding: Work supported by Department of Energy contract DE–AC02–76SF00515. In LCLS-II, after acceleration and compression and just before entering the undulator, the beam passes through roughly 2.5 km of 24.5 mm (radius) stainless steel pipe. The bunch that passes through the pipe is extremely short with an rms of 8 um for the nominal 100 pC case. Thus, even though the pipe has a large aperture, the wake that applies is the short-range resistive wall wakefield. It turns out that the wake supplies needed dechirping to the LCLS-II beam before it enters the undulator. The LCLS-II bunch distribution is approximately uniform, and therefore the wake induced voltage is characterized by a rather linear voltage chirp for short bunches. However for bunches longer than 25 um (300 pC at 1 kA) the wake starts to become nonlinear, effectively limiting the maximum charge with which the LCLS-II can operate. In this note we calculate the wake, discuss the confidence in the calculation, and investigate how to improve the induced chirp linearity and/or strength. Finally, we also study the strength and effects of the transverse (dipole) resistive wall wakefield.

TUPP137	High Power Solid-State Amplifiers. New Developments and Technology Comparison	controls, operation, power-supply, impedance	733
	G.B. Sharkov, A.I. Botyachkova, E.V. Ivanov, N.G. Kalugin, A.A. Krasnov, K.K. Naraianamurtkhi, K.I. Nikolskiy, S.A. Polikhov, I. Řežanov, A.Yu. Smirnov, P. Yazev Siemens Research Center, Moscow,, Russia A.I. Botyachkova National Research Nuclear University (MEPhI), Moscow, Russia
	Funding: Skolkovo Foundation, contract #44 from 2011.11.14 We present a newly developed compact and cost effective SSPA with megawatt range output power and scalable architecture. System components test results are discussed. A comparison of the state-of-the-art vacuum tube and solid-state technologies of RF power amplifiers for scientific accelerators is given. Solid-state microwave generator, Siemens

TUPP138	Analysis of New High-Q0 SRF Cavity Tests by Nitrogen Gas Doping at Jefferson Lab	cavity, injection, SRF, niobium	736
	A.D. Palczewski, R.L. Geng, C.E. Reece JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. In order to refine systematic understanding and establish confident process control, Jefferson Lab has joined with partners to investigate and thoroughly characterize the dramatically higher Q0 of 1.3 GHz niobium cavities first reported by FNAL in 2013[1]. With partial support from the LCLS-II project, JLab has undertaken a parametric study of nitrogen doping in vacuum furnace at 800 C followed by variable depth surface removal in the 5 - 20 μm range. Q0 above 3×10¹⁰ are typical at 2.0 K and 16 MV/m accelerating field. We report observations from the single cell study and current interpretations. In addition to the parametric single cell study, we also report on the ongoing serial testing of six nitrogen-doped 9-cell cavities as baseline prototypes for LCLS-II. [1] A. Grassellino, et al., Supercon. Sci.and Tech., 2013. 26(10): p. 102001
	Poster TUPP138 [4.214 MB]

TUPP140	Observation of >GV/m Decelerating Fields in Dielectric Lined Waveguides	wakefield, radiation, experiment, electron	743
	B.D. O'Shea, G. Andonian, K.L. Fitzmorris, S. Hakimi, J. Harrison, J.B. Rosenzweig, O. Williams UCLA, Los Angeles, California, USA M.J. Hogan, V. Yakimenko SLAC, Menlo Park, California, USA
	Recent experimental measurements of the energy lost to wakefields in a dielectric lined waveguide are presented. These measurements demonstrate average decelerating gradients on the order of >1 GV/m, for two different structures. The measurements were made at the Facility for Advanced aCcelerator Experimental Tests (FACET) at SLAC National Laboratory using sub-millimeter diameter fifteen-centimeter long quartz fibers of annular cross section. The unique extremely short, high charge, ultra relativistic beam at FACET (200 fs, 3 nC, 20 GeV) allows the use of dielectric wakefield structures of unprecedented size and length. In addition to experimental results, we support conclusions with simulation and theoretical work. This measurement builds on a large body of work previously performed using dielectric wakefield structures in an effort to provide high gradient accelerating structures for tomorrows linear colliders.

WEIOA01	Construction and RF Conditioning of the Cell-Coupled Drift Tube Linac (CCDTL) for Linac4 at CERN	linac, coupling, cavity, quadrupole	746
	A.G. Tribendis, Y.A. Biryuchevsky, E. Kendjebulatov, Ya.G. Kruchkov, E. Rotov, A.A. Zhukov BINP SB RAS, Novosibirsk, Russia Y. Cuvet, A. Dallocchio, J.-F. Fuchs, F. Gerigk, J.-M. Giguet, J. Hansen, T. Muranaka, E. Page, B. Riffaud, N. Thaus, M. Tortrat, M. Vretenar, R. Wegner CERN, Geneva, Switzerland M.Y. Naumenko RFNC-VNIITF, Snezhinsk, Chelyabinsk region, Russia
	This paper reports on the construction experience of the Linac4 CCDTL, which took place in two Russian institutes in the framework of three ISTC projects in close collaboration with CERN. The tanks were constructed at VNIITF, Snezhinsk, while the drift tubes and supports were made at BINP, Novosibirsk. All structures were then assembled and tuned at BINP before shipment to CERN where the high-power conditioning took place. The tuning principles, quality checks and conditioning results are presented.
	Slides WEIOA01 [4.909 MB]

THIOA03	Status of the HIE-ISOLDE Linac	cryomodule, linac, cavity, solenoid	795
	W. Venturini Delsolaro, L. Alberty, L. Arnaudon, K. Artoos, J. Bauche, A.P. Bernardes, J.A. Bousquet, E. Bravin, S. Calatroni, E.D. Cantero, O. Capatina, N. Delruelle, D. Duarte Ramos, M. Elias, F. Formenti, M.A. Fraser, J. Gayde, S. Giron, N.M. Jecklin, Y. Kadi, G. Kautzmann, Y. Leclercq, P. Maesen, V. Mertens, E. Montesinos, V. Parma, G.J. Rosaz, K.M. Schirm, E. Siesling, D. Smekens, A. Sublet, M. Therasse, D. Valuch, G. Vandoni, E. Vergara Fernandez, D. Voulot, L.R. Williams, P. Zhang CERN, Geneva, Switzerland
	The HIE-ISOLDE project aims at increasing the energy of the radioactive beams (RIB) of REX-ISOLDE from the present 3 MeV/u up to 10 MeV/u for A/q up to 4.5. This will be accomplished by means of a new superconducting linac, based on independently phased quarter wave resonators using the Nb sputtering on copper technology, and working at 101.28 MHz. The focusing elements are superconducting solenoids providing 13.5 T2m field integral. These active elements are contained in a common vacuum cryostat. The presentation will cover the status of advancement of the HIE-ISOLDE linac technical systems. The performance of the superconducting elements will be presented, together with the assembly work of the cryomodule in clean room and the planned qualification tests in the horizontal test facility at CERN
	Slides THIOA03 [24.692 MB]

THIOA04	Superconducting Cavities and Cryomodules for Proton and Deuteron Linacs	cavity, cryomodule, linac, cryogenics	801
	G. Devanz CEA/IRFU, Gif-sur-Yvette, France
	We review the recent advances in the design plans and test results of the superconducting structures for proton (ESS) and deuteron linacs (SPIRAL2, IFMIF). A variety of RF resonators are used for this purposes, from multicell elliptical cavities for the acceleration of pulsed proton beams to half and quarter wave resonators for CW deuteron beams. The increase in beam power with respect to previous generations of linacs brings new challenges to cavities and RF couplers. Test results of the available SRF prototypes and cryomodules of the aforementioned projects will be presented.
	Slides THIOA04 [6.785 MB]

THIOB01	Cryogenic Plants for SRF Linacs	SRF, cryomodule, linac, cryogenics	811
	D. Arenius JLab, Newport News, Virginia, USA
	Review of the types of considerations that go into cryo-plant design. Arenius is a world expert on this topic and has led the completion of the upgraded cryo-plant at Jefferson Lab, and has recently provided substantial input on this question to the new LCLS II project.
	Slides THIOB01 [4.382 MB]

THPP016	Nitrogen-Treated Cavity Testing at Cornell	cavity, SRF, niobium, linac	866
	D. Gonnella, F. Furuta, G.M. Ge, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: U.S. Department of Energy Recent results from Cornell, FNAL, and TJNAF have shown that superconducting RF cavities given a heat treatment in a nitrogen atmosphere show higher Q₀ at operating gradients at 2.0 K than standard SRF cavities. Here we present on recent results at Cornell in which five single cell cavities and three 9-cell cavities were tested after receiving various nitrogen-doping treatments. Cavity performance was correlated with treatment, and samples treated with the cavities were analyzed with SIMS. These results provide new insights into the science behind the excellent performance that is observed in these cavities.

THPP036	CERN Linac4 Drift Tube Linac Manufacturing and Assembly	linac, DTL, alignment, interface	923
	S. Ramberger, P. Bourquin, A. Cherif, Y. Cuvet, A. Dallocchio, G. Favre, J.-F. Fuchs, J.-M. Geisser, F. Gerigk, J.-M. Giguet, J. Hansen, M. Polini, S. Sgobba, N. Thaus, M. Vretenar CERN, Geneva, Switzerland
	The manufacturing of the Linac4 Drift Tube Linac (DTL) components has been completed and the assembly of the structures is in its final stages. 3 tanks of 3.9m, 7.3m, and 7.3m, designed to accelerate a 40mA average pulse current H–beam from 3 to 50MeV, are being assembled from 2, 4 and 4 segments of about 2.0m length, containing each from 22 drift tubes at the low energy end, down to only 6 at the high energy end. Due to its peculiar design avoiding adjustment mechanisms on the drift tube, tight tolerances have to be maintained in the production. This paper discusses the assembly stages that are used to achieve the tolerances over the full length of the structures. Metrology results on the assembled DTL Tank1 confirm the required precision.

THPP039	Electron Beam Welding and Vacuum Brazing Characterization for SRF Cavities	niobium, cavity, electron, interface	932
	N. Valverde Alonso, S. Atieh, I. Aviles Santillana, S. Calatroni, O. Capatina, L.M.A. Ferreira, F. Pillon, M. Redondas Monteserin, T. Renaglia, K.M. Schirm, T. Tardy, A. Vacca CERN, Geneva, Switzerland
	In the framework of the SPL R&D effort at CERN, development design efforts study the joining of dissimilar metals: bulk niobium for the superconducting RF cavities and stainless steel (316LN) or titanium alloys (Ti-6Al-4V and Nb55Ti) for the cryostats. Joining techniques of electron beam welding (EBW) and vacuum brazing are particularly important for these applications. These processes have been used in the accelerator community and developed into generally accepted “best practice”. Studies were performed to update the existing knowledge, and comprehensively characterise these joints via mechanical and metallurgical investigations using modern available technologies. The developed solutions are described in detail, some currently being applied uniquely at CERN.
	Poster THPP039 [5.324 MB]

THPP044	ESS Normal Conducting Linac Status and Plans	linac, rfq, proton, DTL	948
	A. Ponton, B. Cheymol, R. De Prisco, M. Eshraqi, R. Miyamoto, E. Sargsyan ESS, Lund, Sweden G. Bourdelle, M. Desmons, A. France, O. Piquet, B. Pottin CEA/DSM/IRFU, France I. Bustinduy, P.J. González, J.L. Muñoz, I. Rueda, F. Sordo ESS Bilbao, Bilbao, Spain L. Celona, S. Gammino, L. Neri INFN/LNS, Catania, Italy M. Comunian, F. Grespan, A. Pisent, C. R. Roncolato INFN/LNL, Legnaro (PD), Italy P. Mereu INFN-Torino, Torino, Italy
	The ESS Normal Conducting (NC) linac is composed of an ion source, a Low Energy Beam Transport line, a Radio Frequency Quarupole (RFQ), a Medium Energy Beam Transport Line (MEBT) and a Drift Tube Linac (DTL). It creates, bunches and accelerates the proton beam up to 90 MeV before injecting into the superconducting linac which will deliver a 5 MW beam onto the neutron production target. The construction of the NC linac is part of a broad collaboration involving experts of various Labs in Europe. The technical chalenges and the collaboration strategy for the NC linac will be presented.

THPP046	SRF Highbay Technical Infrastructure for FRIB Production at Michigan State University	SRF, cavity, cryomodule, controls	954
	L. Popielarski, F. Casagrande, C. Compton, T. Elkin, A. Fila, P.E. Gibson, M. Hodek, L. Hodges, I.M. Malloch, C. Nguyen, R. Oweiss, J.P. Ozelis, J. Popielarski, C. Thronson, D.R. Victory, T. Xu FRIB, East Lansing, Michigan, USA M. Leitner LBNL, Berkeley, California, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE- SC0000661 Michigan State University (MSU) has funded the construction of a new 27,000 square foot high bay building to house the Superconducting Radio Frequency (SRF) infrastructure for the Facility for Rare Isotope Beams (FRIB) production requirements. The construction has been completed and beneficial occupancy began on May 19th, 2014. The new SRF highbay includes over 4,000 square feet of cleanroom and chemistry facility space, automated cavity etch tools, ultra pure water systems, cold mass component inspection area, hydrogen degassing furnace, SRF testing capabilities for three vertical test Dewars and two horizontal cryomodule test bunkers with dedicated helium refrigeration system. The status of the technical equipment design, installation and commissioning will be presented.

THPP050	Status of 325 MHz Main Couplers for PXIE	cavity, Windows, multipactoring, pick-up	963
	S. Kazakov, B.M. Hanna, T.N. Khabiboulline, V. Poloubotko, O.V. Pronitchev, L. Ristori, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	The Project X Injector Experiment (PXIE) at Fermilab will include one cryomodule with eight 325 MHz single spoke superconductive cavities (SSR1). Each cavity requires approximately 2 kW CW RF power for 1 mA beam current operation. A future upgrade will require up to 8 kW RF power per cavity. Fermilab has designed, procured and tested two prototype couplers for the SSR type cavities. Status of the 325 MHz main coupler development for PXIE is reported.

THPP079	Prototyping Progress of SSR1 Single Spoke Resonator for RAON	cavity, target, simulation, heavy-ion	1
	H.J. Cha, M.O. Hyun, D. Jeon, H.C. Jung, H.J. Kim IBS, Daejeon, Republic of Korea
	The fabrication of prototypes for four different types of superconducting cavities (QWR, HWR, SSR1, and SSR2) for the Korean heavy ion accelerator, “RAON” is in progress. In this presentation, we report the current status of the SSR1 cavity (β=0.3 and f=325 MHz) prototype fabrication based on the technical designs. The issues when forming the niobium cavities such as pressing, machining, electron beam welding are reviewed. The RF testing for the prototypes, which will be done in near future, is also discussed.

THPP087	ESS DTL Design and Drift Tube Prototypes	DTL, linac, coupling, quadrupole	1050
	F. Grespan, M. Comunian, A. Pisent, M. Poggi, C. R. Roncolato INFN/LNL, Legnaro (PD), Italy P. Mereu INFN-Torino, Torino, Italy
	The Drift Tube Linac (DTL) for the ESS accelerator will accelerate protons up to 62.5 mA average pulse current from 3.62 to 90 MeV. The 5 tanks composing the DTL are designed to operate at 352.2 MHz in pulses of 2.86 ms long with a repetition rate of 14 Hz. The accelerating field is around 3.1 MV/m, constant in each tank. Permanent magnet quadrupoles (PMQs) are used as focusing element in a FODO lattice. The empty drift tubes accommodate Electro Magnetic Dipoles (EMDs) and Beam Position Monitors (BPMs) in order to implement beam corrective schemes. A complete set of Drift Tubes is under construction that is BPM, EMD and PMQ types. These prototypes are aimed to validate the design with the involved integration issues of the various components, as well as the overall technological and assembly process. This paper presents the main mechanical choices and the status of the prototyping program of the Drift Tubes.

THPP089	High Power Conditioning of Annular-Ring Coupled Structures for the J-PARC Linac	operation, linac, cavity, coupling	1053
	H. Ao, T. Ito, Y. Nemoto, H. Oguri, N. Ouchi, J. Tamura JAEA/J-PARC, Tokai-mura, Japan H. Asano Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan Z. Fang, K. Futatsukawa, K. Nanmo, T. Sugimura KEK, Ibaraki, Japan
	The linac of Japan Proton Accelerator Research Complex (J-PARC), which is an injector to a 3-GeV synchrotron, comprised a 3-MeV RFQ, 50-MeV DTLs and 181-MeV Separated-type DTLs. From September 2013, 25 annular-ring coupled structure (ACS) cavities were additionally installed to increase the linac beam energy up to 400 MeV and achieve 1-MW beam power of the 3-GeV synchrotron. After installation work the high power conditioning was started from December 2013 and most of the ACS cavities were conditioned within three weeks. We passed through some troubles and finally finished conditioning all the cavities until the middle of January 2014. In this paper, we present the conditioning results and how to handle the issue in the conditioning process.
	Slides THPP089 [7.756 MB]

THPP096	RF Coaxial Resonator for Investigating Multipactor Discharges on Metal and Dielectric Surfaces	multipactoring, electron, experiment, coupling	1074
	M. El Khaldi, W. Kaabi, P. Lepercq, Y. Peinaud LAL, Orsay, France
	Multipactor discharge is a phenomenon in which electrons impact one or more material surfaces in resonance with an alternating electric field. The discharge can occur for a wide range of frequencies, from the MHz range to tens of GHz, and in wide array of geometries if the impacted surface has a secondary electron emission (SEE) yield larger than one. The discharge can take place on a single surface or between two surfaces. A novel coaxial resonator to investigate two-surface multipactor discharges on metal and dielectric surfaces in the gap region under vacuum conditions has been designed and tested. The resonator is ~ 100 mm in length with an outer diameter of ~ 60 mm (internal dimensions). A pulsed RF source delivers up to 30 W average power over a wide frequency range 650-900 MHz to the RF resonator. The incident and reflected RF signals are monitored by calibrated RF diodes. An electron probe provides temporal measurements of the multipacting electron current with respect to the RF power. These experiments were successful in identifying multipacting and allowed us the evaluation of a home made sputtered titanium nitride (TiN) thin layers as a Multipactor suppressor.

THPP099	Status of Superconducting Cavity and Cryomodule Development at MHI	cavity, cryomodule, niobium, superconducting-cavity	1084
	T. Yanagisawa, H. Hara, N. Ikeda, K. Sennyu MHI, Hiroshima, Japan
	MHI's activities for ｓuperconducting accelerator are reported. MHI had developed several procedure and method of ILC cavity production for stable quality and cost reduction. And we had fabricated and installed cryomodules for ILC and ERL R&D. These activities are reported in detail.

THPP100	Result of MHI 2-Cell Seamless Dumb-Bell Cavity Vertical Test	cavity, superconducting-cavity, linac, electron	1087
	K. Okihira, H. Hara, N. Ikeda, F. Inoue, K. Sennyu MHI, Kobe, Japan R.L. Geng, R.A. Rimmer JLab, Newport News, Virginia, USA E. Kako KEK, Ibaraki, Japan
	MHI have supplied several 9-cell cavities for STF (R&D of ILC project at KEK) and have been considering production method for stable quality and cost reduction, seamless dumb-bell cavity was one of them. We had fabricated a 2 cell seamless dumb-bell cavity for cost reduction and measured RF performance in collaboration with JLab, KEK and MHI. Surface treatment recipe for ILC was applied for MHI 2-cell cavity and vertical test was performed at JLab. The cavity reached Eacc=32.4MV/m after BCP and EP. Details of the result are reported.

THPP114	The SwissFEL RF Gun: Manufacturing and Proof of Precision by Field Profile Measurements	gun, electron, cathode, coupling	1117
	U. Ellenberger, H. Blumer, M. Kleeb, L. Paly, M. Probst Paul Scherrer Institute, Villigen PSI, Switzerland M. Bopp, A. Citterio, H. Fitze, J.-Y. Raguin, A. Scherer, L. Stingelin PSI, Villigen PSI, Switzerland
	The high brightness electron source for SwissFEL is an in-house built 2.6 cell normal-conducting RF gun which is scaled to the RF frequency of 2'998.8 MHz. The RF gun is capable of operating at 100 Hz repetition rate and produces electron bunches at the exit of the RF gun of an energy of 7 MeV. Key features of the RF gun are described and how they have been implemented in the manufacturing process. RF field measurements of the RF gun are presented to account for the mechanical precision reached after manufacturing. The RF gun has been thoroughly tested in the SwissFEL injector test facility.

THPP129	Carbon Field Emission Strip Cathode Electron Source	electron, cathode, simulation, focusing	1
	T.V. Bondarenko, A.I. Botyachkova, G.G. Karpinskiy, S.A. Polikhov, G.B. Sharkov Siemens Research Center, Moscow,, Russia A.I. Botyachkova, G.G. Karpinskiy National Research Nuclear University (MEPhI), Moscow, Russia A.E. Geisler, O. Heid Siemens AG, Erlangen, Germany
	Over the recent years carbon nanostructure cathodes have become promising as a high brightness electron sources with large working area for field emission structures. Measurements and calculations of a field emission strip cathode based on carbon structure and a unit for its investigation are presented in the article. For measuring of the cathode emitting properties and determination of the electrons initial parameters used in the electron beam computer simulation the experimental setup is been developed. The setup consists of the high-voltage triode electrode system and allows to investigate the voltage-current characteristics of the cathode and to estimate the electron distribution of the beam on the anode surface. The anode electron distribution evaluations are processed by the measurements of the emitted X-ray focal spot on the anode by application of the CCD camera. Verification of the simulated electron beam dynamics can be obtained by application of the experimentally acquired data.
	Poster THPP129 [4.088 MB]

THPP131	Series Superconducting Cavity Production for the HIE-ISOLDE Project at CERN	cavity, cryomodule, niobium, pick-up	1165
	M. Therasse, L. Alberty, K. Artoos, S. Calatroni, O. Capatina, A. D'Elia, N.M. Jecklin, Y. Kadi, I. Mondino, K.M. Schirm, A. Sublet, W. Venturini Delsolaro, P. Zhang CERN, Geneva, Switzerland
	In the context of the HIE-ISOLDE linac upgrade at CERN, the phase 1 planned to boost the energy of the machine from 3 MeV/u to 5 MeV/u. For this purpose, it is planned to install 2 cryomodules based on quarter waves resonators (QWRs) made by Niobium sputtering on Copper. The poster will present the different steps of the cavity series production since the reception from the industry to the cavity storage before cryomodule assembly. We will describe the cavity preparation included the resonance frequency measurement, the chemical treatment, the cavity rinsing, the Niobium coating and the RF test at 4.5K.

THPP138	Measurements of Beam Current and Energy-Dispersion for Ion Beam with Multi-Components	ion, ion-source, experiment, simulation	1185
	A.L. Zhang University of Chinese Academy of Sciences, Beijing, People's Republic of China J.E. Chen, Z.Y. Guo, S.X. Peng, H.T. Ren, Y. Xu, T. Zhang, J. Zhao PKU, Beijing, People's Republic of China J.E. Chen Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
	Funding: This work is supported by the National Science Foundation of China（Grant Nos. 91126004). The multi-component ion beam is very common in nuclear physics, materials physics and most kind of ion source. But the diagnosis of multi-component ion beam [1] can be difficult because of its complex composition and irregular energy-dispersion. We need an effective way to analyzing the multi-component ion beam. There is a multi-component ion beam whose total beam current varies from 1 mA to 50mA and the beam energy can be 20keV to 150keV. In this paper, four methods to analyzing this multi-component ion beam are described, which are Faraday cup array method, fluorescent screen with Faraday cup, movable aperture with conductive fluorescent screen, and current calibration method, respectively. The distributions and currents of the separated ion beams are obtained by means of the four methods, and the current and energy-dispersion of each component might be measured at the same time. This is of special interest for beams with multi-components. Detailed description and comparison of the four methods are discussed in this paper. Correspondence Author:Peng ShiXiang. Email: sxpeng@pku.edu.cn
	Poster THPP138 [0.419 MB]

THPP140	High Transparent Matched Window for Standing Wave Linear Accelerators	linac, electron, network, coupling	1192
	A. Leggieri, F. Di Paolo, D. Passi Università degli Studi di Roma "Tor Vergata", Roma, Italy A. Ciccotelli, G. Felici S.I.T., Aprilia, Italy
	This paper proposes a particular Dielectric Window (DW) for Standing Wave (SW) Linear Accelerators (LINAC’s). This study investigates the in-frequency return loss behavior of the LINAC, in order to improve matching and transmitting conditions while maintaining the optimum coupling between LINAC and High Power Microwave (HPMW) source. Device design is single-frequency based and considers the DW interface as an Input Matching Network (IMN) at the LINAC Normal Mode (NM) working frequency. Thus, design formulas are provided and Computer Aided Design (CAD) techniques are proposed. A prototype has been made and tested by performing cold S-parameter and Percentage Depth Dose (PDD) measurements of a LINAC with the proposed DW and with a traditional DW. The proposed device offers more energy transport attitude over the traditional DW, as shown by a return loss increase of 167% and an output electron energy increase of 5.5% while maintaining the same LINAC input power settings. This solution can offer a decrease of power line size, weight and cost. An after brazing global improvement of the accelerator figures of merit is also possible, as this study have demonstrated. [1]Hiroyuki Arai, 1986 [2]K. Hirano, 1995 [3]Y. Otake, 1995 [5]A. Leggieri, 2014 [6]A. C. Ugural, 2003 [7]A. Leggieri, 2014 [8]F. Di Paolo, 2000 [9]N. Marcuvitz, 1951

Paper

Title

Other Keywords

Page

MOPP094

Latest Improvements of the SPring-8 Linac for High Reliability

linac, operation, electron, injection

276

S. Suzuki, H. Dewa, H. Hanaki, T. Kobayashi, T. Magome, A. Mizuno, T. Taniuchi, K. Yanagida
JASRI/SPring-8, Hyogo-ken, Japan
T. Asaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

In order to perform stable injection to the 8GeV SPring-8 storage ring, which is performing the top-up operation, the high reliability of the linac has been advanced as follows: For reduction of phase variations caused by the waveguide deformation due to the variations of temperature or atmospheric pressure, the waveguide circuit of SF6 enclosure type, which fed RF powers to the bunching section, was replaced with that of vacuum type. And S-band 10MW circulators and isolators of vacuum type were adopted for the first time in the world. The timing system was improved so that the interval time of the beam injection into the 8GeV booster synchrotron and the 1.5 GeV NewSUBARU storage ring has been reduced to 1 sec from 15 seconds, respectively, even in the top-up operation of both storage rings. As a result, the stored current by the top-up operation were further stabilized. The stored current of the NewSUBARU storage ring was stabilized to 0.18% from 0.31%. The electron gun cathode assembly has been developed to reduce the dark emission from a grid plate by the double grid method and the electrolytic polishing.

MOPP115

Plasma Processing of Nb Surfaces for SRF Cavities

plasma, SRF, cavity, accelerating-gradient

323

P.V. Tyagi, M. Doleans, S.-H. Kim
ORNL, Oak Ridge, Tennessee, USA
R. Afanador, C.J. McMahan
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This work is supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
Field emission is one of the most critical issues to achieve high performances of niobium (Nb) superconducting radio frequency (SRF) cavities. Field emission is mainly related to contaminants present at top surface of SRF cavities that act as electron emitters at high gradient operation and limit the cavity accelerating gradient. An R&D program at the Spallation Neutron Source (SNS) is in place* aiming to develop an in-situ plasma processing technique to remove some of the residual contaminants from inner surfaces of Nb cavities and improve their performance. The plasma processing R&D has first concentrated on removing hydrocarbon contamination from top surface of SRF cavities. Results from the surface studies on plasma processed Nb samples will be presented in this article and showed the removal of hydrocarbons from Nb surfaces as well as improvement of the surface workfuntion (WF).
*M. Doleans et al. “Plasma processing R&D for the SNS superconducting linac RF cavities” Proceedings of 2013 SRF workshop, Paris, France

Slides MOPP115 [1.405 MB]

MOPP118

C-Band Load Development for the High Power Test of the SwissFEL RF Pulse Compressor

impedance, cavity, klystron, coupling

329

A. Citterio, J. Stettler, R. Zennaro
PSI, Villigen PSI, Switzerland

The SwissFEL C-band Linac will have 26 RF modules, each one consisting of a solid-state modulator and a 50 MW klystron that feeds a pulse compressor and four two meters long accelerating structures. The pulse compressor is of the Barrel Open Cavity type (BOC). A first prototype was successfully produced and high-power tested, reaching for full power klystron operation a peak power of 300 MW. For testing this BOC at maximum RF power, a broadband load was designed and built, based on a ridge waveguide design and high permeability stainless steel. Based on the experience gained at CERN for CLIC X-band high power loads, the RF design of the load was optimized to ensure high losses for a quite large range of magnetic steels. Test pieces were realized in three different magnetic steels to choose the best suited material commercially available. This paper reports about the RF design, material study, production and impressive high power results of this C-band load.

MOPP119

Measurements and High Power Test of the First C-band Accelerating Structure for SwissFEL

operation, FEL, klystron, linac

333

R. Zennaro, J. Alex, A. Citterio, J.-Y. Raguin
PSI, Villigen PSI, Switzerland

The SwissFEL project is based on a 5.8 GeV C-band Linac which is composed of 10⁴ accelerating structures with a length of 2 m each. Due to the absence of dimple tuning no local frequency correction is possible and hence ultra-precise machining is required. The paper reports on both low level and high power RF test of the first nominal structure produced. The required mechanical precision has been reached and the structure has been successfully power tested to a gradient larger than 50 MV/m, well above the nominal level of 28 MV/m. The measured dark current and break down rates are well in the specifications.

MOPP124

Development of a 3 MeV Prototype RFQ Structure for High Intensity Proton Linac for ISNS

rfq, ion, operation, proton

345

S.C. Joshi, A. Chaturvedi, S.K. Chauhan, K.K. Das, G.V. Kane, S.V. Kokil, B. Oraon, S. Raghvendra, N.K. Sharma
RRCAT, Indore (M.P.), India

Raja Ramanna Centre for Advanced Technology (RRCAT) has taken up a program on R&D activities of a 1 GeV, high intensity superconducting proton linac for a spallation neutron source. A 3 MeV Radio Frequency Quadrupole (RFQ) will be used as front end of the pulsed proton linac. A full scale prototype RFQ structure has been designed and fabricated to validate the physics design and manufacturing procedures. The total of 3.46 meter has been divided in three segments for ease in machining. The fabricated RFQ structure has been assembled for low power RF characterization. The RFQ frequency and field tuning exercise is being carried out using 48 stub tuners. The paper will also present the engineering design aspects and fabrication issues for the full scale RFQ structure.

MOPP134

Superconducting Accelerating Cavity Pressure Sensitivity Analysis and Stiffening

cavity, proton, simulation, linac

373

J. Rodnizki, Y. Ben Aliz, A. Grin, Z. Horvitz, A. Perry, L. Weissman
Soreq NRC, Yavne, Israel
G.K. Davis
JLab, Newport News, Virginia, USA
J.R. Delayen
ODU, Norfolk, Virginia, USA

The SARAF Prototype Superconducting Module (PSM) houses six 176 MHz Half Wave Resonators(HWR). The PSM accelerates protons and deuterons from 1.5 MeV/u to 4 and 5.6 MeV. The HWRs are highly sensitive to the coolant liquid Helium pressure fluctuations which limit the available beam power to 2kW per cavity out of 4kW RF amplifier and coupler and so might limit the available beam current to 2mA depending on the output energy. The flat shape of the cavity along the beam line in the area of the high electric field generates the high sensitivity of the Eigen mode frequency to helium pressure. The evaluated cavity sensitivity is full consistent with the measured values. It was explored that the tuning system (the fog structure) has a significant contribution to the cavity sensitivity. By using ribs or by modifying the rigidity of the fog we may reduce the HWR sensitivity by a factor of 3. This analysis is applied to study the stresses on the cavity during cool down and warm up to avoid plastic deformation as the Niobium yield is an order of magnitude lower in room temperature.

TUIOB04

DTL Construction Status of CSNS Project

DTL, linac, neutron, ion

423

H.C. Liu, S. Fu, J. Peng, S. Wang
IHEP, Beijing, People's Republic of China

Linac of Chinese Spallation Neutron Source (CSNS) project is under construction. The ion source is tested and good performance of beam current is obtained. The low level RF tuning is underway of the RFQ and assembling of DTL will start soon. Not only the construction of hardware, but some commissioning software packages have been developed and tested.

Slides TUIOB04 [4.772 MB]

TUIOC01

Large Scale Testing of SRF Cavities and Modules

cryomodule, cavity, software, laser

426

J. Świerbleski
IFJ-PAN, Kraków, Poland

Series production of SRF cavities, s.c. quadrupole packages and accelerator modules for the European XFEL is in full swing. Mid 2014 approx. 400 cavities will be tested, the testing of quadrupoles will be almost finished, and regular module testing will be established. Thus the talk should emphasize the quasi industrial testing of these components, of course including a good overview about the used somewhat unique AMTF infrastructure.

Slides TUIOC01 [3.094 MB]

TUPP040

Preliminary Functional Analysis of ESS Superconducting Radio-Frequency Linac

cryomodule, controls, interface, SRF

522

C. Darve, N. Elias, J. Fydrych, D.P. Piso
ESS, Lund, Sweden

The European Spallation Source (ESS) is one of Europe's largest planned research infrastructures. The collaborative project is funded by a collaboration of 17 European countries and is under design and construction in Lund, Sweden. Three families of Superconducting Radio-Frequency (SRF) cavities are being prototyped, counting the spoke resonators with a geometric beta of 0.5, medium-beta elliptical cavities (βg=0.67) and high-beta elliptical cavities (bg=0.86). The 5 MW, 2.86 ms long pulse proton accelerator has a repetition frequency of 14 Hz (4 % duty cycle), and a beam current of 62.5 mA. The cavities and power couplers are assembled into cryomodules, which are operating using RF sources, cryogenic and water coolings. This document describes the process of the ESS SRF cryomodule operation while refereeing to operational modes.

TUPP049

Test Stand for 325 MHz Power Couplers

cavity, multipactoring, pick-up, high-voltage

538

S. Kazakov, B.M. Hanna, T.N. Khabiboulline, V. Poloubotko, O.V. Pronitchev, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

325 MHz superconducting Single Spoke resonators (SSR1) will be utilized in the Project X Injector Experiment (PXIE). Developed in Fermilab the main power coupler will be supply 2kW CW RF power to each cavity. Fermilab developed and designed the special test stand where the couplers will be tested up to 10 kW and design properties be confirmed. This paper describes the design of the coupler test stand and preliminary results of the tests.

TUPP055

Progress on Euclid SRF Conical Half-Wave Resonator Project

cavity, niobium, SRF, proton

547

E.N. Zaplatin
FZJ, Jülich, Germany
T.L. Grimm
Niowave, Inc., Lansing, Michigan, USA
A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: This Work is supported by the DOE SBIR Program, contract # DE-SC0006302.
Euclid conical Half-Wave Resonator (cHWR) project develops 162.5 MHz β=v/c=0.11 accelerator structure for the high-intensity proton accelerator complex proposed at Fermi National Accelerator Laboratory. The main idea of this project is to provide a self-compensation cavity design together with its helium vessel to minimize the resonant frequency dependence on external loads. A unique cavity side-tuning option is also under development. Niowave, Inc. proposed a complete cavity production procedure including preparation of technical drawings, processing steps and resonator high-gradient tests to demonstrate such possibility for the private company. Here we present the procedure of the cavity and helium vessel fabrication, cavity preparation and initial experimental results.

TUPP057

In Situ Measurement of Mechanical Vibrations of a 4-Rod RFQ at GSI

laser, rfq, operation, quadrupole

553

P. Gerhard, L. Groening, K.-O. Voss
GSI, Darmstadt, Germany

A new 4-rod CW Radio Frequency Quadrupole was commissioned at the high charge state injector HLI at the UNILAC in 2009. It is in operation since 2010*. At high rf amplitudes strong modulations of the rf reflection emerge, with a modulation frequency of approximately 500 Hz. They are attributed to mechanical oscillations of the rods, excited by the rf pulse. The high fraction of reflected rf power severely limits the pulse length and rf amplitude achievable. As these modulations could only be seen during the rf pulse by means of rf measurements, a direct observation of the mechanical vibrations was desirable. Such measurements have been conducted using a commercial laser vibrometer, allowing for the investigation of the mechanical behavior of the RFQ independent of the presence of rf power. After a short introduction of the method, the results will be presented and compared with rf measurements and simulations.
*: P. Gerhard et al., “Experience with a 4–Rod CW RFQ”, LINAC’12, Sept. 2012, Tel Aviv, THPB035

TUPP071

Vortex-Penetration Field at a Groove with a Depth Smaller than the Penetration Depth

cavity, experiment, framework

590

T. Kubo
KEK, Ibaraki, Japan

Analytical models of the magnetic field enhancement at pits were presented at SRF2013 last year. In this presentation, I will show updated models.
proceedings of SRF 2013, Paris, France (2013), p. 430

TUPP077

High Precision Manufacturing for LINAC's

linac, extraction, controls, laser

603

F.M. Mirapeix, J. Añel
HTS, Mendaro, Spain
J. Amores, J. Presa, A. Urzainki
DMP, Mendaro, Spain

A big effort in R&D focused to the LINAC devices together with the know-how already deployed through emblematic projects places DMP in the state of the art of the extreme precision mechanics. This mechanic culture makes of DMP a natural partner in early stages of design or driver of a comprehensive solution, optimizing industrial risks, quality and due date. Surface roughness below 1 nanometer, figure errors better than 50 nanometers in OFE copper enhances lifetime and performance of many devices for LINAC's. Research in joining techniques and combining several alternative technologies to traditional machining improves figure stability and makes complex cooling systems possible.

TUPP084

Surface Treatment Facilities for SCRF Cavities at RISP

cavity, superconducting-cavity, niobium, superconducting-RF

619

J. Joo, D. Jeon, M.J. Joung, Y. Jung, H.J. Kim, M. Lee
IBS, Daejeon, Republic of Korea

Rare Isotope Science Project is engaged in the fabrication of four types of superconducting RF cavities. The surface treatment is one of the important processes of superconducting RF cavity fabrication. New superconducting RF cavity processing systems have been designed and developed for the etching of niobium in buffered chemical polish at RISP. The safety precautions used in protecting the operator from the acids used in the etchant and from the fumes given of during the process are discussed. All of the new hardware will be located in RISP Munji Superconducting Cavity Test Facility.

TUPP085

RAON Cryomodule Design for QWR, HWR, SSR1 and SSR2

cryomodule, simulation, linac, cavity

622

W.K. Kim, H. Kim, H.J. Kim, Y. Kim, M. Lee, G.-T. Park
IBS, Daejeon, Republic of Korea

The accelerator called RAON which will be built in Korea has four kinds of superconducting cavities such as QWR, HWR, SSR1 and SSR2, operating at 2 K and 4.5 K [1]. The current status of design for the QWR, HWR, SSR1 and SSR2 cryomodules are reported. The issues included in the paper are thermal and structural design results of the components such as supports and thermal shield in the cryomodules. The cryomodule hosts the superconducting cavities in high vacuum and thermally insulated environment in order to maintain the operating temperature of superconducting cavities. It also keeps the cavities in a good alignment to the beam line. It has an interface for supplying RF power to cavities between cold and warm components. The whole configuration of the integrated system is also presented. This paper presents the detailed design of the cryomodule.

TUPP088

The Fabrication of the β=0.12 HWR at RISP

niobium, cavity, target, electron

628

G.-T. Park, H.J. Cha, Y. Jung, H. Kim, W.K. Kim
IBS, Daejeon, Republic of Korea

At RISP, the superconducting cavities have been developed to construct RAON, the heavy ion accelerator. Among the cavities, the fabrication of the QWR (Quarter wave resonator) and the HWR (Half wave resonator)are complete. The detailed fabrication processes including material inspection, forming, the electron beam welding, and the clamp up test are described.

TUPP093

The Couplers for the IFMIF-EVEDA RFQ High Power Test Stand at LNL: Design, Construction and Operation

cavity, coupling, rfq, simulation

643

E. Fagotti, L. Antoniazzi, M.G. Giacchini, F. Grespan, M. Montis, A. Palmieri, A. Pisent, C. R. Roncolato
INFN/LNL, Legnaro (PD), Italy

In order to assess the critical aspects of the IFMIF-EVEDA RFQ construction procedure and operation, it was decided to perform a High Power Test of a subset of the RFQ consisting in its last 550 mm three modules (out of 18) plus a Prototype Module, 390 mm long, used as RF plug. These modules are going to be tested at full power in CW of INFN LNL Labs, in the so-called RFQ High Power Test Stand. For such a purpose, a RF tube-based amplifier capable of 220 kW CW output power at the operational frequency of 175 MHz was purchased from an Italian company. A critical component of this test is the RF power coupler. Therefore INFN-LNL developed a design of two identical water-cooled loop antenna couplers, built with OFE copper and vacuum sealed with a commercially available 6”1/8 Alumina planar window. These couplers were tested separately on an aluminium coupling cavity. In particular one of them acts as a power feeder, while the other one, connected with a 200 kW water-cooled load, acts as a receiver. In this paper, the main aspects of the design, construction and tests performed on the couplers and coupling cavity will be described.

TUPP095

High-Power Test Results of the RFQ III in J-PARC Linac

rfq, operation, cavity, ion

649

T. Morishita, K. Hasegawa, K. Hirano, Y. Kondo, H. Oguri, S. Yamazaki
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
T. Hori
JAEA, Ibaraki-ken, Japan
F. Naito, T. Sugimura, A. Takagi
KEK, Ibaraki, Japan

The J-PARC accelerator comprises an injector linac, a 3-GeV Rapid-Cycling Synchrotron and a 50-GeV Main Ring. The beam energy of the linac has been upgraded from 181MeV to 400MeV in 2013. For the beam current upgrade, the new frontend (RF ion source, RFQ, chopping system) installation is scheduled in summer 2014 for 1MW operation at RCS. The RFQ III, which is designed for 50mA beam acceleration from 0.05MeV to 3MeV, has been fabricated and the high-power test has started at April 2013 at the test station in the J-PARC. The test station consists of the ion source, the LEBT, the RFQ, and the diagnostics devices. The nominal RF power and RF duty of the RFQ III are 380kW and 3%(0.6ms and 50Hz), respectively. The high-power conditioning reached to the 120% of the nominal power with 1.5% (0.6ms, 25Hz) RF duty within 24 hours. Then, we performed the beam operation at the test station and measured beam parameters after the RFQ III. The results of the high-power conditioning and the stability of the RFQ operation with beam will be discussed.

TUPP122

Roughness Tolerances in the Undulator Vacuum Chamber of LCLS-II

impedance, undulator, wakefield, FEL

708

K.L.F. Bane, G.V. Stupakov
SLAC, Menlo Park, California, USA

Funding: Work supported by Department of Energy contract DE–AC02–76SF00515.
In LCLS-II, after acceleration and compression and just before entering the undulator, the beam passes through roughly 2.5 km of 24.5 mm (radius) stainless steel pipe. The bunch that passes through the pipe is extremely short with an rms of 8 um for the nominal 100 pC case. Thus, even though the pipe has a large aperture, the wake that applies is the short-range resistive wall wakefield. It turns out that the wake supplies needed dechirping to the LCLS-II beam before it enters the undulator. The LCLS-II bunch distribution is approximately uniform, and therefore the wake induced voltage is characterized by a rather linear voltage chirp for short bunches. However for bunches longer than 25 um (300 pC at 1 kA) the wake starts to become nonlinear, effectively limiting the maximum charge with which the LCLS-II can operate. In this note we calculate the wake, discuss the confidence in the calculation, and investigate how to improve the induced chirp linearity and/or strength. Finally, we also study the strength and effects of the transverse (dipole) resistive wall wakefield.

TUPP137

High Power Solid-State Amplifiers. New Developments and Technology Comparison

controls, operation, power-supply, impedance

733

G.B. Sharkov, A.I. Botyachkova, E.V. Ivanov, N.G. Kalugin, A.A. Krasnov, K.K. Naraianamurtkhi, K.I. Nikolskiy, S.A. Polikhov, I. Řežanov, A.Yu. Smirnov, P. Yazev
Siemens Research Center, Moscow,, Russia
A.I. Botyachkova
National Research Nuclear University (MEPhI), Moscow, Russia

Funding: Skolkovo Foundation, contract #44 from 2011.11.14
We present a newly developed compact and cost effective SSPA with megawatt range output power and scalable architecture. System components test results are discussed. A comparison of the state-of-the-art vacuum tube and solid-state technologies of RF power amplifiers for scientific accelerators is given.
Solid-state microwave generator, Siemens

TUPP138

Analysis of New High-Q0 SRF Cavity Tests by Nitrogen Gas Doping at Jefferson Lab

cavity, injection, SRF, niobium

736

A.D. Palczewski, R.L. Geng, C.E. Reece
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
In order to refine systematic understanding and establish confident process control, Jefferson Lab has joined with partners to investigate and thoroughly characterize the dramatically higher Q0 of 1.3 GHz niobium cavities first reported by FNAL in 2013[1]. With partial support from the LCLS-II project, JLab has undertaken a parametric study of nitrogen doping in vacuum furnace at 800 C followed by variable depth surface removal in the 5 - 20 μm range. Q0 above 3×10¹⁰ are typical at 2.0 K and 16 MV/m accelerating field. We report observations from the single cell study and current interpretations. In addition to the parametric single cell study, we also report on the ongoing serial testing of six nitrogen-doped 9-cell cavities as baseline prototypes for LCLS-II.
[1] A. Grassellino, et al., Supercon. Sci.and Tech., 2013. 26(10): p. 102001

Poster TUPP138 [4.214 MB]

TUPP140

Observation of >GV/m Decelerating Fields in Dielectric Lined Waveguides

wakefield, radiation, experiment, electron

743

B.D. O'Shea, G. Andonian, K.L. Fitzmorris, S. Hakimi, J. Harrison, J.B. Rosenzweig, O. Williams
UCLA, Los Angeles, California, USA
M.J. Hogan, V. Yakimenko
SLAC, Menlo Park, California, USA

Recent experimental measurements of the energy lost to wakefields in a dielectric lined waveguide are presented. These measurements demonstrate average decelerating gradients on the order of >1 GV/m, for two different structures. The measurements were made at the Facility for Advanced aCcelerator Experimental Tests (FACET) at SLAC National Laboratory using sub-millimeter diameter fifteen-centimeter long quartz fibers of annular cross section. The unique extremely short, high charge, ultra relativistic beam at FACET (200 fs, 3 nC, 20 GeV) allows the use of dielectric wakefield structures of unprecedented size and length. In addition to experimental results, we support conclusions with simulation and theoretical work. This measurement builds on a large body of work previously performed using dielectric wakefield structures in an effort to provide high gradient accelerating structures for tomorrows linear colliders.

WEIOA01

Construction and RF Conditioning of the Cell-Coupled Drift Tube Linac (CCDTL) for Linac4 at CERN

linac, coupling, cavity, quadrupole

746

A.G. Tribendis, Y.A. Biryuchevsky, E. Kendjebulatov, Ya.G. Kruchkov, E. Rotov, A.A. Zhukov
BINP SB RAS, Novosibirsk, Russia
Y. Cuvet, A. Dallocchio, J.-F. Fuchs, F. Gerigk, J.-M. Giguet, J. Hansen, T. Muranaka, E. Page, B. Riffaud, N. Thaus, M. Tortrat, M. Vretenar, R. Wegner
CERN, Geneva, Switzerland
M.Y. Naumenko
RFNC-VNIITF, Snezhinsk, Chelyabinsk region, Russia

This paper reports on the construction experience of the Linac4 CCDTL, which took place in two Russian institutes in the framework of three ISTC projects in close collaboration with CERN. The tanks were constructed at VNIITF, Snezhinsk, while the drift tubes and supports were made at BINP, Novosibirsk. All structures were then assembled and tuned at BINP before shipment to CERN where the high-power conditioning took place. The tuning principles, quality checks and conditioning results are presented.

Slides WEIOA01 [4.909 MB]

THIOA03

Status of the HIE-ISOLDE Linac

cryomodule, linac, cavity, solenoid

795

W. Venturini Delsolaro, L. Alberty, L. Arnaudon, K. Artoos, J. Bauche, A.P. Bernardes, J.A. Bousquet, E. Bravin, S. Calatroni, E.D. Cantero, O. Capatina, N. Delruelle, D. Duarte Ramos, M. Elias, F. Formenti, M.A. Fraser, J. Gayde, S. Giron, N.M. Jecklin, Y. Kadi, G. Kautzmann, Y. Leclercq, P. Maesen, V. Mertens, E. Montesinos, V. Parma, G.J. Rosaz, K.M. Schirm, E. Siesling, D. Smekens, A. Sublet, M. Therasse, D. Valuch, G. Vandoni, E. Vergara Fernandez, D. Voulot, L.R. Williams, P. Zhang
CERN, Geneva, Switzerland

The HIE-ISOLDE project aims at increasing the energy of the radioactive beams (RIB) of REX-ISOLDE from the present 3 MeV/u up to 10 MeV/u for A/q up to 4.5. This will be accomplished by means of a new superconducting linac, based on independently phased quarter wave resonators using the Nb sputtering on copper technology, and working at 101.28 MHz. The focusing elements are superconducting solenoids providing 13.5 T2m field integral. These active elements are contained in a common vacuum cryostat. The presentation will cover the status of advancement of the HIE-ISOLDE linac technical systems. The performance of the superconducting elements will be presented, together with the assembly work of the cryomodule in clean room and the planned qualification tests in the horizontal test facility at CERN

Slides THIOA03 [24.692 MB]

THIOA04

Superconducting Cavities and Cryomodules for Proton and Deuteron Linacs

cavity, cryomodule, linac, cryogenics

801

G. Devanz
CEA/IRFU, Gif-sur-Yvette, France

We review the recent advances in the design plans and test results of the superconducting structures for proton (ESS) and deuteron linacs (SPIRAL2, IFMIF). A variety of RF resonators are used for this purposes, from multicell elliptical cavities for the acceleration of pulsed proton beams to half and quarter wave resonators for CW deuteron beams. The increase in beam power with respect to previous generations of linacs brings new challenges to cavities and RF couplers. Test results of the available SRF prototypes and cryomodules of the aforementioned projects will be presented.

Slides THIOA04 [6.785 MB]

THIOB01

Cryogenic Plants for SRF Linacs

SRF, cryomodule, linac, cryogenics

811

D. Arenius
JLab, Newport News, Virginia, USA

Review of the types of considerations that go into cryo-plant design. Arenius is a world expert on this topic and has led the completion of the upgraded cryo-plant at Jefferson Lab, and has recently provided substantial input on this question to the new LCLS II project.

Slides THIOB01 [4.382 MB]

THPP016

Nitrogen-Treated Cavity Testing at Cornell

cavity, SRF, niobium, linac

866

D. Gonnella, F. Furuta, G.M. Ge, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: U.S. Department of Energy
Recent results from Cornell, FNAL, and TJNAF have shown that superconducting RF cavities given a heat treatment in a nitrogen atmosphere show higher Q₀ at operating gradients at 2.0 K than standard SRF cavities. Here we present on recent results at Cornell in which five single cell cavities and three 9-cell cavities were tested after receiving various nitrogen-doping treatments. Cavity performance was correlated with treatment, and samples treated with the cavities were analyzed with SIMS. These results provide new insights into the science behind the excellent performance that is observed in these cavities.

THPP036

CERN Linac4 Drift Tube Linac Manufacturing and Assembly

linac, DTL, alignment, interface

923

S. Ramberger, P. Bourquin, A. Cherif, Y. Cuvet, A. Dallocchio, G. Favre, J.-F. Fuchs, J.-M. Geisser, F. Gerigk, J.-M. Giguet, J. Hansen, M. Polini, S. Sgobba, N. Thaus, M. Vretenar
CERN, Geneva, Switzerland

The manufacturing of the Linac4 Drift Tube Linac (DTL) components has been completed and the assembly of the structures is in its final stages. 3 tanks of 3.9m, 7.3m, and 7.3m, designed to accelerate a 40mA average pulse current H–beam from 3 to 50MeV, are being assembled from 2, 4 and 4 segments of about 2.0m length, containing each from 22 drift tubes at the low energy end, down to only 6 at the high energy end. Due to its peculiar design avoiding adjustment mechanisms on the drift tube, tight tolerances have to be maintained in the production. This paper discusses the assembly stages that are used to achieve the tolerances over the full length of the structures. Metrology results on the assembled DTL Tank1 confirm the required precision.

THPP039

Electron Beam Welding and Vacuum Brazing Characterization for SRF Cavities

niobium, cavity, electron, interface

932

N. Valverde Alonso, S. Atieh, I. Aviles Santillana, S. Calatroni, O. Capatina, L.M.A. Ferreira, F. Pillon, M. Redondas Monteserin, T. Renaglia, K.M. Schirm, T. Tardy, A. Vacca
CERN, Geneva, Switzerland

In the framework of the SPL R&D effort at CERN, development design efforts study the joining of dissimilar metals: bulk niobium for the superconducting RF cavities and stainless steel (316LN) or titanium alloys (Ti-6Al-4V and Nb55Ti) for the cryostats. Joining techniques of electron beam welding (EBW) and vacuum brazing are particularly important for these applications. These processes have been used in the accelerator community and developed into generally accepted “best practice”. Studies were performed to update the existing knowledge, and comprehensively characterise these joints via mechanical and metallurgical investigations using modern available technologies. The developed solutions are described in detail, some currently being applied uniquely at CERN.

Poster THPP039 [5.324 MB]

THPP044

ESS Normal Conducting Linac Status and Plans

linac, rfq, proton, DTL

948

A. Ponton, B. Cheymol, R. De Prisco, M. Eshraqi, R. Miyamoto, E. Sargsyan
ESS, Lund, Sweden
G. Bourdelle, M. Desmons, A. France, O. Piquet, B. Pottin
CEA/DSM/IRFU, France
I. Bustinduy, P.J. González, J.L. Muñoz, I. Rueda, F. Sordo
ESS Bilbao, Bilbao, Spain
L. Celona, S. Gammino, L. Neri
INFN/LNS, Catania, Italy
M. Comunian, F. Grespan, A. Pisent, C. R. Roncolato
INFN/LNL, Legnaro (PD), Italy
P. Mereu
INFN-Torino, Torino, Italy

The ESS Normal Conducting (NC) linac is composed of an ion source, a Low Energy Beam Transport line, a Radio Frequency Quarupole (RFQ), a Medium Energy Beam Transport Line (MEBT) and a Drift Tube Linac (DTL). It creates, bunches and accelerates the proton beam up to 90 MeV before injecting into the superconducting linac which will deliver a 5 MW beam onto the neutron production target. The construction of the NC linac is part of a broad collaboration involving experts of various Labs in Europe. The technical chalenges and the collaboration strategy for the NC linac will be presented.

THPP046

SRF Highbay Technical Infrastructure for FRIB Production at Michigan State University

SRF, cavity, cryomodule, controls

954

L. Popielarski, F. Casagrande, C. Compton, T. Elkin, A. Fila, P.E. Gibson, M. Hodek, L. Hodges, I.M. Malloch, C. Nguyen, R. Oweiss, J.P. Ozelis, J. Popielarski, C. Thronson, D.R. Victory, T. Xu
FRIB, East Lansing, Michigan, USA
M. Leitner
LBNL, Berkeley, California, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE- SC0000661
Michigan State University (MSU) has funded the construction of a new 27,000 square foot high bay building to house the Superconducting Radio Frequency (SRF) infrastructure for the Facility for Rare Isotope Beams (FRIB) production requirements. The construction has been completed and beneficial occupancy began on May 19th, 2014. The new SRF highbay includes over 4,000 square feet of cleanroom and chemistry facility space, automated cavity etch tools, ultra pure water systems, cold mass component inspection area, hydrogen degassing furnace, SRF testing capabilities for three vertical test Dewars and two horizontal cryomodule test bunkers with dedicated helium refrigeration system. The status of the technical equipment design, installation and commissioning will be presented.

THPP050

Status of 325 MHz Main Couplers for PXIE

cavity, Windows, multipactoring, pick-up

963

S. Kazakov, B.M. Hanna, T.N. Khabiboulline, V. Poloubotko, O.V. Pronitchev, L. Ristori, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

The Project X Injector Experiment (PXIE) at Fermilab will include one cryomodule with eight 325 MHz single spoke superconductive cavities (SSR1). Each cavity requires approximately 2 kW CW RF power for 1 mA beam current operation. A future upgrade will require up to 8 kW RF power per cavity. Fermilab has designed, procured and tested two prototype couplers for the SSR type cavities. Status of the 325 MHz main coupler development for PXIE is reported.

THPP079

Prototyping Progress of SSR1 Single Spoke Resonator for RAON

cavity, target, simulation, heavy-ion

1

H.J. Cha, M.O. Hyun, D. Jeon, H.C. Jung, H.J. Kim
IBS, Daejeon, Republic of Korea

The fabrication of prototypes for four different types of superconducting cavities (QWR, HWR, SSR1, and SSR2) for the Korean heavy ion accelerator, “RAON” is in progress. In this presentation, we report the current status of the SSR1 cavity (β=0.3 and f=325 MHz) prototype fabrication based on the technical designs. The issues when forming the niobium cavities such as pressing, machining, electron beam welding are reviewed. The RF testing for the prototypes, which will be done in near future, is also discussed.

THPP087

ESS DTL Design and Drift Tube Prototypes

DTL, linac, coupling, quadrupole

1050

F. Grespan, M. Comunian, A. Pisent, M. Poggi, C. R. Roncolato
INFN/LNL, Legnaro (PD), Italy
P. Mereu
INFN-Torino, Torino, Italy

The Drift Tube Linac (DTL) for the ESS accelerator will accelerate protons up to 62.5 mA average pulse current from 3.62 to 90 MeV. The 5 tanks composing the DTL are designed to operate at 352.2 MHz in pulses of 2.86 ms long with a repetition rate of 14 Hz. The accelerating field is around 3.1 MV/m, constant in each tank. Permanent magnet quadrupoles (PMQs) are used as focusing element in a FODO lattice. The empty drift tubes accommodate Electro Magnetic Dipoles (EMDs) and Beam Position Monitors (BPMs) in order to implement beam corrective schemes. A complete set of Drift Tubes is under construction that is BPM, EMD and PMQ types. These prototypes are aimed to validate the design with the involved integration issues of the various components, as well as the overall technological and assembly process. This paper presents the main mechanical choices and the status of the prototyping program of the Drift Tubes.

THPP089

High Power Conditioning of Annular-Ring Coupled Structures for the J-PARC Linac

operation, linac, cavity, coupling

1053

H. Ao, T. Ito, Y. Nemoto, H. Oguri, N. Ouchi, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan
H. Asano
Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan
Z. Fang, K. Futatsukawa, K. Nanmo, T. Sugimura
KEK, Ibaraki, Japan

The linac of Japan Proton Accelerator Research Complex (J-PARC), which is an injector to a 3-GeV synchrotron, comprised a 3-MeV RFQ, 50-MeV DTLs and 181-MeV Separated-type DTLs. From September 2013, 25 annular-ring coupled structure (ACS) cavities were additionally installed to increase the linac beam energy up to 400 MeV and achieve 1-MW beam power of the 3-GeV synchrotron. After installation work the high power conditioning was started from December 2013 and most of the ACS cavities were conditioned within three weeks. We passed through some troubles and finally finished conditioning all the cavities until the middle of January 2014. In this paper, we present the conditioning results and how to handle the issue in the conditioning process.

Slides THPP089 [7.756 MB]

THPP096

RF Coaxial Resonator for Investigating Multipactor Discharges on Metal and Dielectric Surfaces

multipactoring, electron, experiment, coupling

1074

M. El Khaldi, W. Kaabi, P. Lepercq, Y. Peinaud
LAL, Orsay, France

Multipactor discharge is a phenomenon in which electrons impact one or more material surfaces in resonance with an alternating electric field. The discharge can occur for a wide range of frequencies, from the MHz range to tens of GHz, and in wide array of geometries if the impacted surface has a secondary electron emission (SEE) yield larger than one. The discharge can take place on a single surface or between two surfaces. A novel coaxial resonator to investigate two-surface multipactor discharges on metal and dielectric surfaces in the gap region under vacuum conditions has been designed and tested. The resonator is ~ 100 mm in length with an outer diameter of ~ 60 mm (internal dimensions). A pulsed RF source delivers up to 30 W average power over a wide frequency range 650-900 MHz to the RF resonator. The incident and reflected RF signals are monitored by calibrated RF diodes. An electron probe provides temporal measurements of the multipacting electron current with respect to the RF power. These experiments were successful in identifying multipacting and allowed us the evaluation of a home made sputtered titanium nitride (TiN) thin layers as a Multipactor suppressor.

THPP099

Status of Superconducting Cavity and Cryomodule Development at MHI

cavity, cryomodule, niobium, superconducting-cavity

1084

T. Yanagisawa, H. Hara, N. Ikeda, K. Sennyu
MHI, Hiroshima, Japan

MHI's activities for ｓuperconducting accelerator are reported. MHI had developed several procedure and method of ILC cavity production for stable quality and cost reduction. And we had fabricated and installed cryomodules for ILC and ERL R&D. These activities are reported in detail.

THPP100

Result of MHI 2-Cell Seamless Dumb-Bell Cavity Vertical Test

cavity, superconducting-cavity, linac, electron

1087

K. Okihira, H. Hara, N. Ikeda, F. Inoue, K. Sennyu
MHI, Kobe, Japan
R.L. Geng, R.A. Rimmer
JLab, Newport News, Virginia, USA
E. Kako
KEK, Ibaraki, Japan

MHI have supplied several 9-cell cavities for STF (R&D of ILC project at KEK) and have been considering production method for stable quality and cost reduction, seamless dumb-bell cavity was one of them. We had fabricated a 2 cell seamless dumb-bell cavity for cost reduction and measured RF performance in collaboration with JLab, KEK and MHI. Surface treatment recipe for ILC was applied for MHI 2-cell cavity and vertical test was performed at JLab. The cavity reached Eacc=32.4MV/m after BCP and EP. Details of the result are reported.

THPP114

The SwissFEL RF Gun: Manufacturing and Proof of Precision by Field Profile Measurements

gun, electron, cathode, coupling

1117

U. Ellenberger, H. Blumer, M. Kleeb, L. Paly, M. Probst
Paul Scherrer Institute, Villigen PSI, Switzerland
M. Bopp, A. Citterio, H. Fitze, J.-Y. Raguin, A. Scherer, L. Stingelin
PSI, Villigen PSI, Switzerland

The high brightness electron source for SwissFEL is an in-house built 2.6 cell normal-conducting RF gun which is scaled to the RF frequency of 2'998.8 MHz. The RF gun is capable of operating at 100 Hz repetition rate and produces electron bunches at the exit of the RF gun of an energy of 7 MeV. Key features of the RF gun are described and how they have been implemented in the manufacturing process. RF field measurements of the RF gun are presented to account for the mechanical precision reached after manufacturing. The RF gun has been thoroughly tested in the SwissFEL injector test facility.

THPP129

Carbon Field Emission Strip Cathode Electron Source

electron, cathode, simulation, focusing

1

T.V. Bondarenko, A.I. Botyachkova, G.G. Karpinskiy, S.A. Polikhov, G.B. Sharkov
Siemens Research Center, Moscow,, Russia
A.I. Botyachkova, G.G. Karpinskiy
National Research Nuclear University (MEPhI), Moscow, Russia
A.E. Geisler, O. Heid
Siemens AG, Erlangen, Germany

Over the recent years carbon nanostructure cathodes have become promising as a high brightness electron sources with large working area for field emission structures. Measurements and calculations of a field emission strip cathode based on carbon structure and a unit for its investigation are presented in the article. For measuring of the cathode emitting properties and determination of the electrons initial parameters used in the electron beam computer simulation the experimental setup is been developed. The setup consists of the high-voltage triode electrode system and allows to investigate the voltage-current characteristics of the cathode and to estimate the electron distribution of the beam on the anode surface. The anode electron distribution evaluations are processed by the measurements of the emitted X-ray focal spot on the anode by application of the CCD camera. Verification of the simulated electron beam dynamics can be obtained by application of the experimentally acquired data.

Poster THPP129 [4.088 MB]

THPP131

Series Superconducting Cavity Production for the HIE-ISOLDE Project at CERN

cavity, cryomodule, niobium, pick-up

1165

M. Therasse, L. Alberty, K. Artoos, S. Calatroni, O. Capatina, A. D'Elia, N.M. Jecklin, Y. Kadi, I. Mondino, K.M. Schirm, A. Sublet, W. Venturini Delsolaro, P. Zhang
CERN, Geneva, Switzerland

In the context of the HIE-ISOLDE linac upgrade at CERN, the phase 1 planned to boost the energy of the machine from 3 MeV/u to 5 MeV/u. For this purpose, it is planned to install 2 cryomodules based on quarter waves resonators (QWRs) made by Niobium sputtering on Copper. The poster will present the different steps of the cavity series production since the reception from the industry to the cavity storage before cryomodule assembly. We will describe the cavity preparation included the resonance frequency measurement, the chemical treatment, the cavity rinsing, the Niobium coating and the RF test at 4.5K.

THPP138

Measurements of Beam Current and Energy-Dispersion for Ion Beam with Multi-Components

ion, ion-source, experiment, simulation

1185

A.L. Zhang
University of Chinese Academy of Sciences, Beijing, People's Republic of China
J.E. Chen, Z.Y. Guo, S.X. Peng, H.T. Ren, Y. Xu, T. Zhang, J. Zhao
PKU, Beijing, People's Republic of China
J.E. Chen
Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China

Funding: This work is supported by the National Science Foundation of China（Grant Nos. 91126004).
The multi-component ion beam is very common in nuclear physics, materials physics and most kind of ion source. But the diagnosis of multi-component ion beam [1] can be difficult because of its complex composition and irregular energy-dispersion. We need an effective way to analyzing the multi-component ion beam. There is a multi-component ion beam whose total beam current varies from 1 mA to 50mA and the beam energy can be 20keV to 150keV. In this paper, four methods to analyzing this multi-component ion beam are described, which are Faraday cup array method, fluorescent screen with Faraday cup, movable aperture with conductive fluorescent screen, and current calibration method, respectively. The distributions and currents of the separated ion beams are obtained by means of the four methods, and the current and energy-dispersion of each component might be measured at the same time. This is of special interest for beams with multi-components. Detailed description and comparison of the four methods are discussed in this paper.
Correspondence Author:Peng ShiXiang.
Email: sxpeng@pku.edu.cn

Poster THPP138 [0.419 MB]

THPP140

High Transparent Matched Window for Standing Wave Linear Accelerators

linac, electron, network, coupling

1192

A. Leggieri, F. Di Paolo, D. Passi
Università degli Studi di Roma "Tor Vergata", Roma, Italy
A. Ciccotelli, G. Felici
S.I.T., Aprilia, Italy

This paper proposes a particular Dielectric Window (DW) for Standing Wave (SW) Linear Accelerators (LINAC’s). This study investigates the in-frequency return loss behavior of the LINAC, in order to improve matching and transmitting conditions while maintaining the optimum coupling between LINAC and High Power Microwave (HPMW) source. Device design is single-frequency based and considers the DW interface as an Input Matching Network (IMN) at the LINAC Normal Mode (NM) working frequency. Thus, design formulas are provided and Computer Aided Design (CAD) techniques are proposed. A prototype has been made and tested by performing cold S-parameter and Percentage Depth Dose (PDD) measurements of a LINAC with the proposed DW and with a traditional DW. The proposed device offers more energy transport attitude over the traditional DW, as shown by a return loss increase of 167% and an output electron energy increase of 5.5% while maintaining the same LINAC input power settings. This solution can offer a decrease of power line size, weight and cost. An after brazing global improvement of the accelerator figures of merit is also possible, as this study have demonstrated.
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