LINAC2016 - Table of Session: THPRC (Poster Session)

Paper	Title	Page
THPRC002	Experimental Study of Nucleation for Nb3Sn Diffusion Coatings on Niobium SRF Cavities
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THOP01	use link to access more material from this paper's primary paper code
	U. Pudasaini, M.J. Kelley The College of William and Mary, Williamsburg, Virginia, USA G.V. Eremeev, M.J. Kelley, C.E. Reece JLab, Newport News, Virginia, USA
	Funding: Partially authored by Jefferson Science Associates under Contract No. DE-AC05-06OR23177. Work at William & Mary supported by Office of High Energy Physics under grant SC0014475 Nb3Sn has the potential to achieve superior performance both in terms of operating temperature (4.2 K vs 2 K) and accelerating gradient resulting in significant reduction in both initial and operating costs of SRF linacs. Cavity interior surface coatings are obtained by two-step vapor diffusion: nucleation followed by deposition. To gain more understanding of nucleation and its effect on the subsequent coating, we investigated the effect of varying parameters in a typical tin/tin chloride process. We report findings obtained by SEM/EDS, AFM, SAM and other materials characterization approaches.
	Slides THPRC002 [2.784 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP01
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THPRC003	Investigation of Nitrogen Absorption Rate and Nitride Growth on SRF Cavity Grade RRR Niobium as a Function of Furnace Temperature
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	A.D. Palczewski, C.E. Reece JLab, Newport News, Virginia, USA M.J. Kelley The College of William and Mary, Williamsburg, Virginia, USA J. Tuggle Virginia Polytechnic Institute and State University, Blacksburg, USA
	Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The current state of the art processing of niobium superconducting radio frequency cavities with nitrogen diffusion is performed at 800C in a furnace with a partial pressure of approximately ~20 mtorr of nitrogen. Multiple studies have shown the bulk of the nitrogen absorbed by the niobium forms a thick (1-3 microns) non-superconducting nitride layer which must be removed to produce optimal RF results. The depth profiling of interstitial nitrogen and surface nitrides has already been probed using SIMS measurements. These measurements have also been modeled by extrapolating data from nitride growth studies performed at atmospheric pressure and temperatures above 1000 C (). One open question is whether there is a diffusion zone at lower temperature in which the niobium will absorb nitrogen but not create a non-superconducting nitride layer; or is the absorption of nitrogen only possible by first forming a nitride buffer layer which then frees up nitrogen for absorption. A systematic study of absorption rate vs. temperature and correlated SIMS measurements needs to be performed to answer this question. We report on the absorption rate vs. temperature from 400 C to 900 C of cavity grade niobium with metallurgically flat witness samples. The witness samples surface depth profile of NbN via SIMS's will be presented and correlated to the absorption. * Gonnella et al., Proceedings of SRF2015 Pre-release MOPB042 (2015) ** Tuggle et al., Investigation of Low-Level Nitrogen in Niobium by Secondary Ion Mass Spectrometry, these proceedings (2016)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP02
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THPRC004	Cold Bead-Pull Test Stand for SRF Cavities
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	A.V. Vélez, A. Frahm, J. Knobloch, A. Neumann HZB, Berlin, Germany
	Bead-pull measurements represent a final step in the fabrication process of an SRF cavity. These tests allow to characterize the flatness of the field profile in order to perform mechanical tuning if needed. These test has been always performed at room temperature, where material properties differ from the superconducting state properties. Still questions like mechanical deformation due to assymetrical thermal shrincage have not yet been answered experimentaly. In this paper, an upgrade of the former Cold-Bead pull system developed by HZB [1] is presented. This test stand is capable of holding a 9-cell Tesla cavity at LHe temperature providing a realistic insight to cavity parameters under realistic conditions. A copper test pill-box is placed in series with the multi-cell cavity in order to perform 1.8K calibration of the bead. Results will be presented on this paper and compared to electromagnetic simulations.
	Slides THPRC004 [2.731 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP03
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THPRC006	Development of 704.4 MHz Power Coupler Window for Myrrha Project	776
	F. Geslin, P. Blache, M. Chabot, J. Lesrel IPN, Orsay, France Ch.L. Lievin, S. Sierra TED, Velizy, France
	Myrrha is an accelerator driven system (ADS) hybrid research reactor designed for spent nuclear fuel burning. The linac controlling the reactor has to be highly reliable (low failure rate). In order to fulfill requirements of ADS projects like Myrrha, IPNO and Thales are involved in a power couplers research and development program. We develop a power coupler window, with MAX RF design, for 80 kW CW input power. During the study, we take account of fabrication and cost issues. We present in this paper the result of simulations needed to design this coupler window. The electromagnetic, thermal and thermo-mechanical simulations were performed with Ansys. The multipacting simulations were performed with Musicc3D, software developed by IPNO. The conditioning and test bench is also described as two prototypes have to be tested this autumn.
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THPRC007	Development of 352.2 Mhz Power Coupler Window for R&D Purposes	779
	F. Geslin, M. Chabot, J. Lesrel, D. Reynet IPN, Orsay, France Ch.L. Lievin, S. Sierra TED, Velizy, France
	IPNO and Thales are conducting power couplers research and development. This paper present a new window design that fulfills European Spallation Source (ESS) requirements (400 kW RF peak power). The results of electromagnetic, thermal, thermo-mechanical, multipacting simulations and the consequences of the new ceramic window of power coupler will be reported. The multipacting simulations were performed with Musicc3D, software developed by IPNO. The new design overcome ceramic's weakness in tension and allows stronger constraints in the power coupler window.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC007
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THPRC008	Status of the Development and Manufacturing of LCLS-II Fundamental Power Couplers	782
	S. Sierra, G. Garcin, Ch.L. Lievin, C. Ribaud, G. Vignette TED, Velizy-Villacoublay, France M. Knaak, A. Navitski, M. Pekeler, L. Zweibaeumer RI Research Instruments GmbH, Bergisch Gladbach, Germany
	For the LCLS-II project, Thales and RI research Instrument are working on the manufacturing and assembly of the Fundamental Power Couplers. The paper describes the production of the Fundamental Power Couplers for the LCLS-II project. The main characteristics of these couplers are remained at 1.3 GHz. It describes the main challenges to be overcome principally on the Warm Internal conductor, with a thickness of copper of 150μm. The results obtained on this coating We describe the results obtained on the prototype phase and the status of the serial production on the date of the paper.
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THPRC009	IF-Mixture Performance During Cavity Conditioning at STF-KEK	785
SPWR027	use link to see paper's listing under its alternate paper code
	S.B. Wibowo Sokendai, Ibaraki, Japan T. Matsumoto, S. Michizono, T. Miura, F. Qiu KEK, Ibaraki, Japan
	The Superconducting rf Test Facility (STF) at High Energy Accelerator Research Organization (KEK) was built for research and development of the International Linear Collider (ILC). In order to satisfy the stability requirement of the accelerating field, a digital low-level RF (LLRF) control system is employed. In this control system, signal from a cavity is down-converted into intermediate frequency (IF) signal before being digitized by analog-to-digital converter (ADC). In order to reduce the required number of ADCs, we proposed a technique that combines several IFs and to be read by a single ADC. Signal reconstruction of each IF is performed by digital signal processing. The performance of this technique, which is named IF-mixture, is reported in this paper.
	Poster THPRC009 [0.992 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC009
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THPRC011	Single LLRF for Multi-Harmonic Buncher	789
	N.R. Usher, D.M. Alt, J.F. Brandon, D.G. Morris, S. Zhao FRIB, East Lansing, Michigan, USA D.M. Alt NSCL, East Lansing, Michigan, USA
	Funding: Work supported by Michigan State University, National Science Foundation: NSF Award Number PHY-1102511. In this paper, a unique low level radio frequency (LLRF) controller designed for a multi-harmonic buncher (MHB) is presented. Different than conventional designs, the single LLRF output contains three RF frequencies (f1, f2 = 2f1, f3 = 3f1) and is fed to a wide band amplifier driving the MHB. The challenge is while driving f1, due to the non-linearity of the amplifier, the f2 and f3 terms will also be generated and will couple into the control of these two modes. Hence an active cancellation algorithm is used to suppress the nonlinear effect of the amplifier. It is demonstrated in a test that the designed LLRF is able to control the amplitude and phase of the three modes in-dependently.
	Poster THPRC011 [1.944 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC011
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THPRC012	Resonance Control System for the CEBAF Separator Upgrade	792
	T. E. Plawski, R. Bachimanchi, B. Bevins, L. Farrish, C. Hovater, G.E. Lahti, M.J. Wissmann JLab, Newport News, Virgina, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The Continuous Electron Beam Accelerator Facility (CEBAF) energy upgrade from 6 GeV to 12 GeV includes the installation of four new 748.5 MHz normal conducting deflecting cavities in the 5th pass extraction region. The RF system employs two digital LLRF systems controlling four normal conducting cavities in a vector sum setting. Cavity tune information of the individual cavities is obtained using a multiplexing scheme of the forward and reflected RF signals. Water skids equipped with heaters and valves are used to control resonance. A new FPGA-based hardware and EPICS-based predictive control algorithm has been developed to support reliable operation of the beam extraction process. This paper presents the architecture design of the existing hardware and software as well as a plan to develop a model predictive control system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC012
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THPRC013	Design of a FRIB Half-Wave Pre-Production Cryomodule	795
	S.J. Miller, H. Ao, B. Bird, G.D. Bryant, B. Bullock, N.K. Bultman, F. Casagrande, C. Compton, A. Facco, W. Hartung, J.D. Hulbert, D.G. Morris, P.N. Ostroumov, J.T. Popielarski, L. Popielarski, M.A. Reaume, K. Saito, M. Shuptar, J. Simon, S. Stark, B.P. Tousignant, J. Wei, J.D. Wenstrom, K. Witgen, T. Xu, Z. Zheng FRIB, East Lansing, USA A. Facco INFN/LNL, Legnaro (PD), Italy M.P. Kelly ANL, Argonne, Illinois, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661. The driver linac for the Facility for Rare Isotope Beams (FRIB) will require the production of 48 cryomodules (CMs). In addition to the β=0.085 quarter-wave CM, FRIB has completed the design of a β=0.53 half-wave CM as a pre-production prototype. This CM will qualify the performance of the resonators, fundamental power couplers, tuners, and cryogenic systems of the β=0.53 half-wave design. In addition to the successful systems qualification; the β=0.53 CM build will also verify the FRIB bottom up assembly and alignment method on a half-wave CM type. The lessons learned from the β=0.085 pre-production CM build including valuable fabrication, sourcing, and assembly experience have been applied to the design of β=0.53 half-wave CM. This paper will report the design of the β=0.53 half-wave CM as well as the CM interfaces within the linac tunnel.
	Poster THPRC013 [0.954 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC013
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THPRC014	RF Losses in 1.3 GHz Cryomodule of The LCLS-II Superconducting CW Linac	798
	A. Saini, A. Lunin, N. Solyak, A.I. Sukhanov, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of a new 4 GeV superconducting (SC) linac that will operate in continuous wave (CW) mode. The major infrastructure investments and the operating cost of a SC CW linac are outlined by its cryogenic requirements. Thus, a detail understanding of RF losses in the cryogenic environment is critical for the entire project. In this paper we review RF losses in a 1.3 GHz accelerating cryomodule of the LCLS-II linac. RF losses due to various sources such untrapped higher order modes (HOMs), resonant losses etc. are addressed and presented here.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC014
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THPRC015	Cool-Down Performance of the Cornell ERL Cryomodules	802
	R.G. Eichhorn, F. Furuta, M. Ge, G.H. Hoffstaetter, M. Liepe, S.R. Markham, T.I. O'Connell, P. Quigley, D.M. Sabol, J. Sears, E.N. Smith, V. Veshcherevich, D. Widger Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	In the framework of the ERL prototyping, Cornell University has built two cryomodules, one injector module and one prototype Main Linac Cryomodule (MLC). In 2015, the MLC was successfully cooled down for the first time. We will report details on the cool-down as well as cycle tests we did in order to achieve slow and fast cool-down of the cavities. We will also report on the improvement we made on the injector cryomodule which also included a modification of the heat exchanger can that allows now a more controlled cool-down, too.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC015
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THPRC016	Assembling Experience of the First Two HIE-ISOLDE Cryomodules	805
	M. Therasse, G. Barlow, S. Bizzaglia, O. Capatina, A. Chrul, P. Demarest, J-B. Deschamps, J. Gayde, M. Gourragne, A. Harrison, G. Kautzmann, Y. Leclercq, D. Mergelkuhl, T. Mikkola, A. Miyazaki, V. Parma, J.A.F. Somoza, M. Struik, S. Teixeira L'pez, W. Venturini Delsolaro, L.R. Williams, P. Zhang CERN, Geneva, Switzerland J. Dequaire Intitek, Lyon, France
	The assembly of the first two cryomodules (CM1 and CM2) of the new superconducting linear accelerator HIE-ISOLDE (High Intensity and Energy ISOLDE), located downstream of the REX-ISOLDE normal conducting accelerator, started one year and half ago. After a delicate assembly phase in the cleanroom which lasted nine months, the first cryomodule was transported to the ISOLDE hall on 2 May 2015 and coupled to the existing REX-ISOLDE accelerator, increasing the energy of the radioactive ion beams from 2.8 to 4.3 MeV per nucleon. The superconducting linac supplied the CERN-ISOLDE Facility, with radioactive zinc ions until the end of the proton run in November 2015. At the beginning of 2016, the second cryomodule was installed in the machine, increasing the energy to 5.5 MeV per nucleon. During commissioning of the first cryomodule in summer 2015, it was found that the performance of the RF superconductive cavities was limited by the over-heating of their RF couplers. The decision was taken to refurbish CM1 and reinstall it at the end of April. In this paper, we present the challenges faced and the experience gained with the cleanroom assembly of the first two cryomodules, especially the construction of the SC RF cavities and their RF ancillaries.
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THPRC017	Performance of SRF Cavity Tuners at LCLS II Prototype Cryomodule at FNAL	808
	J.P. Holzbauer, Y.M. Pischalnikov, W. Schappert, J.C. Yun Fermilab, Batavia, Illinois, USA
	Performances of the fast/slow tuners mounted on the 8 SRF cavities of first LCLS-II prototype cryomodule assembled at FNAL will be presented.
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THPRC021	Status of β=0.53 Pre-Production Cryomodule	811
	H. Ao, B. Bird, G.D. Bryant, B. Bullock, N.K. Bultman, C. Compton, A. Facco, J.D. Hulbert, S.J. Miller, J.T. Popielarski, L. Popielarski, M.A. Reaume, K. Saito, M. Shuptar, J. Simon, S. Stark, B.P. Tousignant, J.D. Wenstrom, K. Witgen, T. Xu, Z. Zheng FRIB, East Lansing, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661. The driver linac for the Facility for Rare Isotope Beams (FRIB) comprises four kinds of cavities (=0.041, 0.085, 0.29, and 0.53) and six types of cryomodules including matching modules. FRIB has started the fabrication of a β=0.53 preproduction cryomodule, which is the first prototype for a half-wave (=0.29 and 0.53) cavity. This paper describes the fabrication progress and the lessons learned from the β=0.53 preproduction cryomodule.
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THPRC022	The Cryogenic Performance of the ARIEL E-Linac Cryomodules	815
	Y. Ma, K. Fong, P.R. Harmer, T. Junginger, D. Kishi, A.N. Koveshnikov, R.E. Laxdal, N. Muller, Z.Y. Yao, V. Zvyagintsev TRIUMF, Vancouver, Canada E. Thoeng UBC & TRIUMF, Vancouver, British Columbia, Canada
	The Advanced Rare Isotope Laboratory (ARIEL) project at TRIUMF requires a 50 MeV superconducting electron Linac consisting of five nine cell 1.3 GHz cavities divided into three cryomodules with one, two and two cavities in each module respectively. The cryomodule design utilizes a unique box cryomodule with a top-loading cold mass. LHe is distributed in parallel to each cryomodule at 4 K and at ~1.2 bar. Each cryomodule has a cryogenic insert on board that receives the 4 K liquid and produces 2 K liquid into a cavity phase separator. In the cryomodules the natural two-phase convection loops, i.e. siphon loop, are installed which supply 4 K liquid to thermal intercepts and return the vaporized liquid to the 4 K reservoir as a refrigerator load. The design of the cryomodule, the simulation results with Ansys Fluent and the results of the cold tests will be presented. mayanyun@triumf.ca
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THPRC023	Cost Reduction for FRIB Magnetic Shielding	818
	Z. Zheng, J.T. Popielarski, K. Saito, T. Xu FRIB, East Lansing, USA
	Funding: *Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 Cryogenic magnetic shielding (A4K) is generally used in SRF cryomodules which is much more expensive than mu-metal used in room temperature. In order to reduce the cost, FRIB QWR and HWR magnetic shieldings were redesign to improve the shielding performance so that mu-metal can be implemented as an alternative shielding material. The magnetic shielding of first FRIB β=0.085 cryomodule was made up of 50% by A4K and 50% by mu-metal. Cavities were tested in 4K and 2K, the results showed that the Q0 of cavities were similar for both shielding materials, which is a success as a validation test for mu-metal magnetic shielding.
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THPRC024	Polarity Check of the FRIB Cryomodule Solenoids by Measuring Leakage Magnetic Field	821
	H. Ao, D. Luo, F. Marti, K. Saito, S. Shanab FRIB, East Lansing, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661. We observed the outside magnetic field of the first β=0.085 production cryomodule while a solenoid and steering dipoles are under operation. This measurement aims to check the polarity on these magnets after the final installation in the accelerating tunnel. This paper also shows the residual magnetic field variation through the degaussing process of these magnets.
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THPRC025	Solid-State Pulsed Power System for a Stripline Kicker	824
	N. Butler, M.P.J. Gaudreau, M.K. Kempkespresenter, M.G. Munderville, F.M. Niell Diversified Technologies, Inc., Bedford, Massachusetts, USA
	Funding: *Work supported by DOE under contract DE-SC0004255 Diversified Technologies, Inc. (DTI) has designed, built, and demonstrated a prototype pulse amplifier for stripline kicker service capable of less than 5 ns rise and fall times, 5 to 90 ns pulse lengths, peak power greater than 13.7 MW at pulse repetition rates exceeding 100 kHz, and measured jitter under 100 ps. The resulting pulse is precise and repeatable, and will be of great interest to accelerator facilities requiring electromagnetic kickers. The pulse generator is based on the original specifications for the NGLS fast deflector. DTI's planar inductive adder configuration uses compensated-silicon power transistors in low inductance leadless packages with a novel charge-pump gate drive to achieve unmatched performance. The prototyping efforts guided the design of the full unit, however the magnetics and transmission line effects of the system were not revealed until the entire unit was assembled. The unit was brought to LBNL, compared with other researcher's efforts, and was judged very favorably. A number of development prototypes have been constructed and tested, including a successful 18.7 kV, 749 A unit. The modularity of this design will enable configuration of systems to a wide range of potential applications in both kickers and other high speed requirements, including high performance radars, directed energy systems, and excimer lasers.
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THPRC026	Optical Design of the PI-Test MEBT Beam Scraping System	827
	A. Saini, A.V. Shemyakin Fermilab, Batavia, Illinois, USA
	PI-Test [1] is an accelerator facility under construction at Fermilab that will provide a platform to demonstrate critical technologies and concept of front-end of the PIP-II superconducting radio frequency (SRF) linac. It will be capable to accelerate an H⁻ ion beam with average current of 2 mA up to 25 MeV in continuous wave (CW) regime. To protect the SRF components from beam irradiation, the Medium Energy Beam Transport (MEBT) section of PI-Test includes an elaborated beam scraping system. It consists of four assemblies spread along the MEBT, with each assembly composed of four radiation-cooled, electrically isolated plates that can be moved into the beam in horizontal and vertical direction. The primary objectives of scraping system are to intercept particles with large transverse action and to protect the beamline elements and SRF linac in case of errors with beam focusing or steering. In this paper we formulate requirements for the scraping system and discuss factors affecting its efficiency. An optical design compatible with PI-Test MEBT is also presented.
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THPRC028	Deflector Design for Spin Rotator in Muon Linear Accelerator	830
	S. Artikova JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Kondo JAEA, Ibaraki-ken, Japan T. Mibe, M. Otani KEK, Tsukuba, Japan
	A muon g-2/EDM experiment based on muon linear accelerator was proposed for the J-PARC muon facility. In this experiment, the ultra-slow muons created in muonium target region will be accelerated to 210 MeV kinetic energy then will be injected into the muon storage ring to measure the decay products depending on the muon spin. Therefore, a spin rotator (device) is a key component of the muon linac. Spin rotator consists of a pair of combined electrostatic and magnetic deflectors and a pair of solenoids which will be placed in between these two deflectors. In this paper, we report the design of these two dispersion-free deflectors and the simulation results of the device performance will be discussed.
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THPRC029	Comissioning Results for a Subharmonic Buncher at REA	833
SPWR035	use link to see paper's listing under its alternate paper code
	D.M. Alt, J.F. Brandon, S.W. Krause, A. Lapierre, D.G. Morris, S. Nash, N.R. Usher, A.C.C. Villari, S.J. Williams, S. Zhao FRIB, East Lansing, USA M.J. Syphers Northern Illinois University, DeKalb, Illinois, USA
	Funding: NSF PHY-1102511 The reaccelerator facility (ReA) at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) offers a unique capability to study reactions with low-energy beams of rare isotopes. A beam from the coupled cyclotron facility is stopped in a gas stopping system, charge bred in an Electron Beam Ion Trap (EBIT), and then reaccelerated in a compact superconducting LINAC. The original beam repetition rate at the ReA targets was the same as the LINAC RF frequency of 80.5 MHz. In order to add the capability to bunch at a lower frequency (desirable for many types of experiments using time of flight data acquisitions) a 16.1 MHz buncher has been designed, constructed, and commissioned. This paper reports the results of the commissioning of the device, and outlines some future avenues for further improvement of the properties of the bunched beam.
	Poster THPRC029 [0.903 MB]
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THPRC030	Plasma Window as Charge Stripper Complement	836
SPWR037	use link to see paper's listing under its alternate paper code
	A. Lajoie NSCL, East Lansing, Michigan, USA A. Hershcovitch, P. Thieberger BNL, Upton, Long Island, New York, USA F. Marti FRIB, East Lansing, USA
	Funding: NSF Cooperative Agreement, Award No. PHY-1102511 Modern ion accelerators, particularly heavy ion accelerators, almost universally make use of charge stripping. A challenge facing facilities, as the demand for higher intensity beams rises, is a stripping media that's highly resistant to degradation, such as a recirculating He gas stripper. A method of keeping the He gas localized in a segment along the beamline by means of a Plasma Window (PW) positioned on both sides of the gas stripper has been proposed and the initial design set forth by Ady Hershcovitch. With a cascaded plasma arc being the interface between high pressure stripper and low pressure beamline, the goal is to minimize gas flowrate from the stripper to the beamline in order to maintain sufficient isolation of the He gas. We present the initial results from the test stand developed at Michigan State University and the planned experimental program that will follow.
	Poster THPRC030 [0.626 MB]
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THPRC031	Manufacturing of MEBT Combined Quadrupole & Steerer Magnets for the Linear IFMIF Prototype Accelerator LIPAC	840
	J. Castellanos, B. Brañas, J. Mollá, C. Oliverpresenter, I. Podadera, F. Toral CIEMAT, Madrid, Spain R. Iturbe, B. López ANTEC Magnets SLU, Vizcaya, Spain O. Nomen IREC, Sant Adria del Besos, Spain
	Funding: This work has been funded by the Spanish Ministry of Economy and Competitiveness under the Agreement as published in BOE, 16/01/2013, page 1988. The Medium Energy Beam Transport line (MEBT) that is being installed on the LIPAC accelerator* will have five quadrupole and steerer magnets which have been recently manufactured and tested. The design of the magnets was done by CIEMAT** and considers a magnetic yoke made of four solid iron quadrants joined together. The yoke integrates four water-cooled coils (quadrupole) and eight air-cooled coils (steerers) made of copper wires. The manufacturing and testing (excluded magnetic measurements) of the five magnets were carried out by the Spanish company ANTECSA. This paper focuses on the technical aspects considered during the manufacturing and the assembly of the different components of the magnets. The details about the geometrical, electrical and hydraulic measurements and tests that were carried out before the magnetic measurements are also described. * A. Mosnier et al., IPAC10, MOPEC056, p.588, Kyoto, Japan (2010) ** C. Oliver et al., IPAC11, WEPO014, p. 2424, San Sebastián, Spain (2011)
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THPRC032	Towards User Defined Web Applications in Accelerator Labs	843
	D. Liu FRIB, East Lansing, USA
	Most Web application users in accelerator labs understand the basics of data types and data structures. They have in-depth knowledge about accelerator physics and other engineering domains. Some even develop software applications by themselves. In the approach of user-defined web applications, a user defines her/his own web application, test and use it first before sharing it to other users. It saves the communication efforts between developers and users, reduces the time from application design to production. Most importantly, users become the owner of the application and naturally the owner of the data that the application collects and produces. This will largely improve an application's quality and user experience. At FRIB, we have been practicing this approach. One of our applications, the traveler, has been developed and operated for about three years, and used by users from various departments including cryomodule, electrical engineering, controls, and business development. The traveler application allows users to design their data collection interface in a what-you-see-is-what-you-get way, and to release it by sharing with other users and groups in the lab. We are now designing and developing a generic data store that will enable users to define their own data structure, to track structure and instance value changes, and to control the access to the data. This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
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Paper

Title

Page

THPRC002

Experimental Study of Nucleation for Nb3Sn Diffusion Coatings on Niobium SRF Cavities

SPWR042

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THOP01

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U. Pudasaini, M.J. Kelley
The College of William and Mary, Williamsburg, Virginia, USA
G.V. Eremeev, M.J. Kelley, C.E. Reece
JLab, Newport News, Virginia, USA

Funding: Partially authored by Jefferson Science Associates under Contract No. DE-AC05-06OR23177. Work at William & Mary supported by Office of High Energy Physics under grant SC0014475
Nb3Sn has the potential to achieve superior performance both in terms of operating temperature (4.2 K vs 2 K) and accelerating gradient resulting in significant reduction in both initial and operating costs of SRF linacs. Cavity interior surface coatings are obtained by two-step vapor diffusion: nucleation followed by deposition. To gain more understanding of nucleation and its effect on the subsequent coating, we investigated the effect of varying parameters in a typical tin/tin chloride process. We report findings obtained by SEM/EDS, AFM, SAM and other materials characterization approaches.

Slides THPRC002 [2.784 MB]

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THPRC003

Investigation of Nitrogen Absorption Rate and Nitride Growth on SRF Cavity Grade RRR Niobium as a Function of Furnace Temperature

THOP02

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A.D. Palczewski, C.E. Reece
JLab, Newport News, Virginia, USA
M.J. Kelley
The College of William and Mary, Williamsburg, Virginia, USA
J. Tuggle
Virginia Polytechnic Institute and State University, Blacksburg, USA

Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The current state of the art processing of niobium superconducting radio frequency cavities with nitrogen diffusion is performed at 800C in a furnace with a partial pressure of approximately ~20 mtorr of nitrogen. Multiple studies have shown the bulk of the nitrogen absorbed by the niobium forms a thick (1-3 microns) non-superconducting nitride layer which must be removed to produce optimal RF results. The depth profiling of interstitial nitrogen and surface nitrides has already been probed using SIMS measurements. These measurements have also been modeled by extrapolating data from nitride growth studies performed at atmospheric pressure and temperatures above 1000 C (**). One open question is whether there is a diffusion zone at lower temperature in which the niobium will absorb nitrogen but not create a non-superconducting nitride layer; or is the absorption of nitrogen only possible by first forming a nitride buffer layer which then frees up nitrogen for absorption. A systematic study of absorption rate vs. temperature and correlated SIMS measurements needs to be performed to answer this question. We report on the absorption rate vs. temperature from 400 C to 900 C of cavity grade niobium with metallurgically flat witness samples. The witness samples surface depth profile of NbN via SIMS's will be presented and correlated to the absorption.**
* Gonnella et al., Proceedings of SRF2015 Pre-release MOPB042 (2015)
** Tuggle et al., Investigation of Low-Level Nitrogen in Niobium by Secondary Ion Mass Spectrometry, these proceedings (2016)

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THPRC004

Cold Bead-Pull Test Stand for SRF Cavities

THOP03

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A.V. Vélez, A. Frahm, J. Knobloch, A. Neumann
HZB, Berlin, Germany

Bead-pull measurements represent a final step in the fabrication process of an SRF cavity. These tests allow to characterize the flatness of the field profile in order to perform mechanical tuning if needed. These test has been always performed at room temperature, where material properties differ from the superconducting state properties. Still questions like mechanical deformation due to assymetrical thermal shrincage have not yet been answered experimentaly. In this paper, an upgrade of the former Cold-Bead pull system developed by HZB [1] is presented. This test stand is capable of holding a 9-cell Tesla cavity at LHe temperature providing a realistic insight to cavity parameters under realistic conditions. A copper test pill-box is placed in series with the multi-cell cavity in order to perform 1.8K calibration of the bead. Results will be presented on this paper and compared to electromagnetic simulations.

Slides THPRC004 [2.731 MB]

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THPRC006

Development of 704.4 MHz Power Coupler Window for Myrrha Project

776

F. Geslin, P. Blache, M. Chabot, J. Lesrel
IPN, Orsay, France
Ch.L. Lievin, S. Sierra
TED, Velizy, France

Myrrha is an accelerator driven system (ADS) hybrid research reactor designed for spent nuclear fuel burning. The linac controlling the reactor has to be highly reliable (low failure rate). In order to fulfill requirements of ADS projects like Myrrha, IPNO and Thales are involved in a power couplers research and development program. We develop a power coupler window, with MAX RF design, for 80 kW CW input power. During the study, we take account of fabrication and cost issues. We present in this paper the result of simulations needed to design this coupler window. The electromagnetic, thermal and thermo-mechanical simulations were performed with Ansys. The multipacting simulations were performed with Musicc3D, software developed by IPNO. The conditioning and test bench is also described as two prototypes have to be tested this autumn.

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THPRC007

Development of 352.2 Mhz Power Coupler Window for R&D Purposes

779

F. Geslin, M. Chabot, J. Lesrel, D. Reynet
IPN, Orsay, France
Ch.L. Lievin, S. Sierra
TED, Velizy, France

IPNO and Thales are conducting power couplers research and development. This paper present a new window design that fulfills European Spallation Source (ESS) requirements (400 kW RF peak power). The results of electromagnetic, thermal, thermo-mechanical, multipacting simulations and the consequences of the new ceramic window of power coupler will be reported. The multipacting simulations were performed with Musicc3D, software developed by IPNO. The new design overcome ceramic's weakness in tension and allows stronger constraints in the power coupler window.

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THPRC008

Status of the Development and Manufacturing of LCLS-II Fundamental Power Couplers

782

S. Sierra, G. Garcin, Ch.L. Lievin, C. Ribaud, G. Vignette
TED, Velizy-Villacoublay, France
M. Knaak, A. Navitski, M. Pekeler, L. Zweibaeumer
RI Research Instruments GmbH, Bergisch Gladbach, Germany

For the LCLS-II project, Thales and RI research Instrument are working on the manufacturing and assembly of the Fundamental Power Couplers. The paper describes the production of the Fundamental Power Couplers for the LCLS-II project. The main characteristics of these couplers are remained at 1.3 GHz. It describes the main challenges to be overcome principally on the Warm Internal conductor, with a thickness of copper of 150μm. The results obtained on this coating We describe the results obtained on the prototype phase and the status of the serial production on the date of the paper.

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THPRC009

IF-Mixture Performance During Cavity Conditioning at STF-KEK

785

SPWR027

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S.B. Wibowo
Sokendai, Ibaraki, Japan
T. Matsumoto, S. Michizono, T. Miura, F. Qiu
KEK, Ibaraki, Japan

The Superconducting rf Test Facility (STF) at High Energy Accelerator Research Organization (KEK) was built for research and development of the International Linear Collider (ILC). In order to satisfy the stability requirement of the accelerating field, a digital low-level RF (LLRF) control system is employed. In this control system, signal from a cavity is down-converted into intermediate frequency (IF) signal before being digitized by analog-to-digital converter (ADC). In order to reduce the required number of ADCs, we proposed a technique that combines several IFs and to be read by a single ADC. Signal reconstruction of each IF is performed by digital signal processing. The performance of this technique, which is named IF-mixture, is reported in this paper.

Poster THPRC009 [0.992 MB]

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THPRC011

Single LLRF for Multi-Harmonic Buncher

789

N.R. Usher, D.M. Alt, J.F. Brandon, D.G. Morris, S. Zhao
FRIB, East Lansing, Michigan, USA
D.M. Alt
NSCL, East Lansing, Michigan, USA

Funding: Work supported by Michigan State University, National Science Foundation: NSF Award Number PHY-1102511.
In this paper, a unique low level radio frequency (LLRF) controller designed for a multi-harmonic buncher (MHB) is presented. Different than conventional designs, the single LLRF output contains three RF frequencies (f1, f2 = 2*f1, f3 = 3*f1) and is fed to a wide band amplifier driving the MHB. The challenge is while driving f1, due to the non-linearity of the amplifier, the f2 and f3 terms will also be generated and will couple into the control of these two modes. Hence an active cancellation algorithm is used to suppress the nonlinear effect of the amplifier. It is demonstrated in a test that the designed LLRF is able to control the amplitude and phase of the three modes in-dependently.

Poster THPRC011 [1.944 MB]

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THPRC012

Resonance Control System for the CEBAF Separator Upgrade

792

T. E. Plawski, R. Bachimanchi, B. Bevins, L. Farrish, C. Hovater, G.E. Lahti, M.J. Wissmann
JLab, Newport News, Virgina, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The Continuous Electron Beam Accelerator Facility (CEBAF) energy upgrade from 6 GeV to 12 GeV includes the installation of four new 748.5 MHz normal conducting deflecting cavities in the 5th pass extraction region. The RF system employs two digital LLRF systems controlling four normal conducting cavities in a vector sum setting. Cavity tune information of the individual cavities is obtained using a multiplexing scheme of the forward and reflected RF signals. Water skids equipped with heaters and valves are used to control resonance. A new FPGA-based hardware and EPICS-based predictive control algorithm has been developed to support reliable operation of the beam extraction process. This paper presents the architecture design of the existing hardware and software as well as a plan to develop a model predictive control system.

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THPRC013

Design of a FRIB Half-Wave Pre-Production Cryomodule

795

S.J. Miller, H. Ao, B. Bird, G.D. Bryant, B. Bullock, N.K. Bultman, F. Casagrande, C. Compton, A. Facco, W. Hartung, J.D. Hulbert, D.G. Morris, P.N. Ostroumov, J.T. Popielarski, L. Popielarski, M.A. Reaume, K. Saito, M. Shuptar, J. Simon, S. Stark, B.P. Tousignant, J. Wei, J.D. Wenstrom, K. Witgen, T. Xu, Z. Zheng
FRIB, East Lansing, USA
A. Facco
INFN/LNL, Legnaro (PD), Italy
M.P. Kelly
ANL, Argonne, Illinois, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661.
The driver linac for the Facility for Rare Isotope Beams (FRIB) will require the production of 48 cryomodules (CMs). In addition to the β=0.085 quarter-wave CM, FRIB has completed the design of a β=0.53 half-wave CM as a pre-production prototype. This CM will qualify the performance of the resonators, fundamental power couplers, tuners, and cryogenic systems of the β=0.53 half-wave design. In addition to the successful systems qualification; the β=0.53 CM build will also verify the FRIB bottom up assembly and alignment method on a half-wave CM type. The lessons learned from the β=0.085 pre-production CM build including valuable fabrication, sourcing, and assembly experience have been applied to the design of β=0.53 half-wave CM. This paper will report the design of the β=0.53 half-wave CM as well as the CM interfaces within the linac tunnel.

Poster THPRC013 [0.954 MB]

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THPRC014

RF Losses in 1.3 GHz Cryomodule of The LCLS-II Superconducting CW Linac

798

A. Saini, A. Lunin, N. Solyak, A.I. Sukhanov, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of a new 4 GeV superconducting (SC) linac that will operate in continuous wave (CW) mode. The major infrastructure investments and the operating cost of a SC CW linac are outlined by its cryogenic requirements. Thus, a detail understanding of RF losses in the cryogenic environment is critical for the entire project. In this paper we review RF losses in a 1.3 GHz accelerating cryomodule of the LCLS-II linac. RF losses due to various sources such untrapped higher order modes (HOMs), resonant losses etc. are addressed and presented here.

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THPRC015

Cool-Down Performance of the Cornell ERL Cryomodules

802

R.G. Eichhorn, F. Furuta, M. Ge, G.H. Hoffstaetter, M. Liepe, S.R. Markham, T.I. O'Connell, P. Quigley, D.M. Sabol, J. Sears, E.N. Smith, V. Veshcherevich, D. Widger
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

In the framework of the ERL prototyping, Cornell University has built two cryomodules, one injector module and one prototype Main Linac Cryomodule (MLC). In 2015, the MLC was successfully cooled down for the first time. We will report details on the cool-down as well as cycle tests we did in order to achieve slow and fast cool-down of the cavities. We will also report on the improvement we made on the injector cryomodule which also included a modification of the heat exchanger can that allows now a more controlled cool-down, too.

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THPRC016

Assembling Experience of the First Two HIE-ISOLDE Cryomodules

805

M. Therasse, G. Barlow, S. Bizzaglia, O. Capatina, A. Chrul, P. Demarest, J-B. Deschamps, J. Gayde, M. Gourragne, A. Harrison, G. Kautzmann, Y. Leclercq, D. Mergelkuhl, T. Mikkola, A. Miyazaki, V. Parma, J.A.F. Somoza, M. Struik, S. Teixeira L'pez, W. Venturini Delsolaro, L.R. Williams, P. Zhang
CERN, Geneva, Switzerland
J. Dequaire
Intitek, Lyon, France

The assembly of the first two cryomodules (CM1 and CM2) of the new superconducting linear accelerator HIE-ISOLDE (High Intensity and Energy ISOLDE), located downstream of the REX-ISOLDE normal conducting accelerator, started one year and half ago. After a delicate assembly phase in the cleanroom which lasted nine months, the first cryomodule was transported to the ISOLDE hall on 2 May 2015 and coupled to the existing REX-ISOLDE accelerator, increasing the energy of the radioactive ion beams from 2.8 to 4.3 MeV per nucleon. The superconducting linac supplied the CERN-ISOLDE Facility, with radioactive zinc ions until the end of the proton run in November 2015. At the beginning of 2016, the second cryomodule was installed in the machine, increasing the energy to 5.5 MeV per nucleon. During commissioning of the first cryomodule in summer 2015, it was found that the performance of the RF superconductive cavities was limited by the over-heating of their RF couplers. The decision was taken to refurbish CM1 and reinstall it at the end of April. In this paper, we present the challenges faced and the experience gained with the cleanroom assembly of the first two cryomodules, especially the construction of the SC RF cavities and their RF ancillaries.

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THPRC017

Performance of SRF Cavity Tuners at LCLS II Prototype Cryomodule at FNAL

808

J.P. Holzbauer, Y.M. Pischalnikov, W. Schappert, J.C. Yun
Fermilab, Batavia, Illinois, USA

Performances of the fast/slow tuners mounted on the 8 SRF cavities of first LCLS-II prototype cryomodule assembled at FNAL will be presented.

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THPRC021

Status of β=0.53 Pre-Production Cryomodule

811

H. Ao, B. Bird, G.D. Bryant, B. Bullock, N.K. Bultman, C. Compton, A. Facco, J.D. Hulbert, S.J. Miller, J.T. Popielarski, L. Popielarski, M.A. Reaume, K. Saito, M. Shuptar, J. Simon, S. Stark, B.P. Tousignant, J.D. Wenstrom, K. Witgen, T. Xu, Z. Zheng
FRIB, East Lansing, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661.
The driver linac for the Facility for Rare Isotope Beams (FRIB) comprises four kinds of cavities (=0.041, 0.085, 0.29, and 0.53) and six types of cryomodules including matching modules. FRIB has started the fabrication of a β=0.53 preproduction cryomodule, which is the first prototype for a half-wave (=0.29 and 0.53) cavity. This paper describes the fabrication progress and the lessons learned from the β=0.53 preproduction cryomodule.

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THPRC022

The Cryogenic Performance of the ARIEL E-Linac Cryomodules

815

Y. Ma, K. Fong, P.R. Harmer, T. Junginger, D. Kishi, A.N. Koveshnikov, R.E. Laxdal, N. Muller, Z.Y. Yao, V. Zvyagintsev
TRIUMF, Vancouver, Canada
E. Thoeng
UBC & TRIUMF, Vancouver, British Columbia, Canada

The Advanced Rare Isotope Laboratory (ARIEL) project at TRIUMF requires a 50 MeV superconducting electron Linac consisting of five nine cell 1.3 GHz cavities divided into three cryomodules with one, two and two cavities in each module respectively. The cryomodule design utilizes a unique box cryomodule with a top-loading cold mass. LHe is distributed in parallel to each cryomodule at 4 K and at ~1.2 bar. Each cryomodule has a cryogenic insert on board that receives the 4 K liquid and produces 2 K liquid into a cavity phase separator. In the cryomodules the natural two-phase convection loops, i.e. siphon loop, are installed which supply 4 K liquid to thermal intercepts and return the vaporized liquid to the 4 K reservoir as a refrigerator load. The design of the cryomodule, the simulation results with Ansys Fluent and the results of the cold tests will be presented.
mayanyun@triumf.ca

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THPRC023

Cost Reduction for FRIB Magnetic Shielding

818

Z. Zheng, J.T. Popielarski, K. Saito, T. Xu
FRIB, East Lansing, USA

Funding: *Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
Cryogenic magnetic shielding (A4K) is generally used in SRF cryomodules which is much more expensive than mu-metal used in room temperature. In order to reduce the cost, FRIB QWR and HWR magnetic shieldings were redesign to improve the shielding performance so that mu-metal can be implemented as an alternative shielding material. The magnetic shielding of first FRIB β=0.085 cryomodule was made up of 50% by A4K and 50% by mu-metal. Cavities were tested in 4K and 2K, the results showed that the Q0 of cavities were similar for both shielding materials, which is a success as a validation test for mu-metal magnetic shielding.

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THPRC024

Polarity Check of the FRIB Cryomodule Solenoids by Measuring Leakage Magnetic Field

821

H. Ao, D. Luo, F. Marti, K. Saito, S. Shanab
FRIB, East Lansing, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661.
We observed the outside magnetic field of the first β=0.085 production cryomodule while a solenoid and steering dipoles are under operation. This measurement aims to check the polarity on these magnets after the final installation in the accelerating tunnel. This paper also shows the residual magnetic field variation through the degaussing process of these magnets.

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THPRC025

Solid-State Pulsed Power System for a Stripline Kicker

824

N. Butler, M.P.J. Gaudreau, M.K. Kempkespresenter, M.G. Munderville, F.M. Niell
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Funding: *Work supported by DOE under contract DE-SC0004255
Diversified Technologies, Inc. (DTI) has designed, built, and demonstrated a prototype pulse amplifier for stripline kicker service capable of less than 5 ns rise and fall times, 5 to 90 ns pulse lengths, peak power greater than 13.7 MW at pulse repetition rates exceeding 100 kHz, and measured jitter under 100 ps. The resulting pulse is precise and repeatable, and will be of great interest to accelerator facilities requiring electromagnetic kickers. The pulse generator is based on the original specifications for the NGLS fast deflector. DTI's planar inductive adder configuration uses compensated-silicon power transistors in low inductance leadless packages with a novel charge-pump gate drive to achieve unmatched performance. The prototyping efforts guided the design of the full unit, however the magnetics and transmission line effects of the system were not revealed until the entire unit was assembled. The unit was brought to LBNL, compared with other researcher's efforts, and was judged very favorably. A number of development prototypes have been constructed and tested, including a successful 18.7 kV, 749 A unit. The modularity of this design will enable configuration of systems to a wide range of potential applications in both kickers and other high speed requirements, including high performance radars, directed energy systems, and excimer lasers.

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THPRC026

Optical Design of the PI-Test MEBT Beam Scraping System

827

A. Saini, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA

PI-Test [1] is an accelerator facility under construction at Fermilab that will provide a platform to demonstrate critical technologies and concept of front-end of the PIP-II superconducting radio frequency (SRF) linac. It will be capable to accelerate an H⁻ ion beam with average current of 2 mA up to 25 MeV in continuous wave (CW) regime. To protect the SRF components from beam irradiation, the Medium Energy Beam Transport (MEBT) section of PI-Test includes an elaborated beam scraping system. It consists of four assemblies spread along the MEBT, with each assembly composed of four radiation-cooled, electrically isolated plates that can be moved into the beam in horizontal and vertical direction. The primary objectives of scraping system are to intercept particles with large transverse action and to protect the beamline elements and SRF linac in case of errors with beam focusing or steering. In this paper we formulate requirements for the scraping system and discuss factors affecting its efficiency. An optical design compatible with PI-Test MEBT is also presented.

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THPRC028

Deflector Design for Spin Rotator in Muon Linear Accelerator

830

S. Artikova
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Kondo
JAEA, Ibaraki-ken, Japan
T. Mibe, M. Otani
KEK, Tsukuba, Japan

A muon g-2/EDM experiment based on muon linear accelerator was proposed for the J-PARC muon facility. In this experiment, the ultra-slow muons created in muonium target region will be accelerated to 210 MeV kinetic energy then will be injected into the muon storage ring to measure the decay products depending on the muon spin. Therefore, a spin rotator (device) is a key component of the muon linac. Spin rotator consists of a pair of combined electrostatic and magnetic deflectors and a pair of solenoids which will be placed in between these two deflectors. In this paper, we report the design of these two dispersion-free deflectors and the simulation results of the device performance will be discussed.

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THPRC029

Comissioning Results for a Subharmonic Buncher at REA

833

SPWR035

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D.M. Alt, J.F. Brandon, S.W. Krause, A. Lapierre, D.G. Morris, S. Nash, N.R. Usher, A.C.C. Villari, S.J. Williams, S. Zhao
FRIB, East Lansing, USA
M.J. Syphers
Northern Illinois University, DeKalb, Illinois, USA

Funding: NSF PHY-1102511
The reaccelerator facility (ReA) at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) offers a unique capability to study reactions with low-energy beams of rare isotopes. A beam from the coupled cyclotron facility is stopped in a gas stopping system, charge bred in an Electron Beam Ion Trap (EBIT), and then reaccelerated in a compact superconducting LINAC. The original beam repetition rate at the ReA targets was the same as the LINAC RF frequency of 80.5 MHz. In order to add the capability to bunch at a lower frequency (desirable for many types of experiments using time of flight data acquisitions) a 16.1 MHz buncher has been designed, constructed, and commissioned. This paper reports the results of the commissioning of the device, and outlines some future avenues for further improvement of the properties of the bunched beam.

Poster THPRC029 [0.903 MB]

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THPRC030

Plasma Window as Charge Stripper Complement

836

SPWR037

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A. Lajoie
NSCL, East Lansing, Michigan, USA
A. Hershcovitch, P. Thieberger
BNL, Upton, Long Island, New York, USA
F. Marti
FRIB, East Lansing, USA

Funding: NSF Cooperative Agreement, Award No. PHY-1102511
Modern ion accelerators, particularly heavy ion accelerators, almost universally make use of charge stripping. A challenge facing facilities, as the demand for higher intensity beams rises, is a stripping media that's highly resistant to degradation, such as a recirculating He gas stripper. A method of keeping the He gas localized in a segment along the beamline by means of a Plasma Window (PW) positioned on both sides of the gas stripper has been proposed and the initial design set forth by Ady Hershcovitch. With a cascaded plasma arc being the interface between high pressure stripper and low pressure beamline, the goal is to minimize gas flowrate from the stripper to the beamline in order to maintain sufficient isolation of the He gas. We present the initial results from the test stand developed at Michigan State University and the planned experimental program that will follow.

Poster THPRC030 [0.626 MB]

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THPRC031

Manufacturing of MEBT Combined Quadrupole & Steerer Magnets for the Linear IFMIF Prototype Accelerator LIPAC

840

J. Castellanos, B. Brañas, J. Mollá, C. Oliverpresenter, I. Podadera, F. Toral
CIEMAT, Madrid, Spain
R. Iturbe, B. López
ANTEC Magnets SLU, Vizcaya, Spain
O. Nomen
IREC, Sant Adria del Besos, Spain

Funding: This work has been funded by the Spanish Ministry of Economy and Competitiveness under the Agreement as published in BOE, 16/01/2013, page 1988.
The Medium Energy Beam Transport line (MEBT) that is being installed on the LIPAC accelerator* will have five quadrupole and steerer magnets which have been recently manufactured and tested. The design of the magnets was done by CIEMAT** and considers a magnetic yoke made of four solid iron quadrants joined together. The yoke integrates four water-cooled coils (quadrupole) and eight air-cooled coils (steerers) made of copper wires. The manufacturing and testing (excluded magnetic measurements) of the five magnets were carried out by the Spanish company ANTECSA. This paper focuses on the technical aspects considered during the manufacturing and the assembly of the different components of the magnets. The details about the geometrical, electrical and hydraulic measurements and tests that were carried out before the magnetic measurements are also described.
* A. Mosnier et al., IPAC10, MOPEC056, p.588, Kyoto, Japan (2010)
** C. Oliver et al., IPAC11, WEPO014, p. 2424, San Sebastián, Spain (2011)

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THPRC032

Towards User Defined Web Applications in Accelerator Labs

843

D. Liu
FRIB, East Lansing, USA

Most Web application users in accelerator labs understand the basics of data types and data structures. They have in-depth knowledge about accelerator physics and other engineering domains. Some even develop software applications by themselves. In the approach of user-defined web applications, a user defines her/his own web application, test and use it first before sharing it to other users. It saves the communication efforts between developers and users, reduces the time from application design to production. Most importantly, users become the owner of the application and naturally the owner of the data that the application collects and produces. This will largely improve an application's quality and user experience. At FRIB, we have been practicing this approach. One of our applications, the traveler, has been developed and operated for about three years, and used by users from various departments including cryomodule, electrical engineering, controls, and business development. The traveler application allows users to design their data collection interface in a what-you-see-is-what-you-get way, and to release it by sharing with other users and groups in the lab. We are now designing and developing a generic data store that will enable users to define their own data structure, to track structure and instance value changes, and to control the access to the data.
This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.

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