TUP —  Tuesday Posters   (29-Mar-11   08:30—17:30)
Paper Title Page
TUP002 Study of Robinson Instabilities with a Higher-Harmonic Cavity for HLS Phase II Project 808
 
  • Y. Zhao, W. Li, L. Wang, C.-F. Wu
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  In the phase II project of Hefei Light Source, a fourth-harmonic “Landau” cavity will be operated in order to suppress coupled-bunch instabilities and increase the beam lifetime of Hefei Storage Ring. Instabilities limit the utility of the higher-harmonic cavity when the storage ring is operated with a small momentum compaction. Analytical modeling and simulations show that the instabilities result from Robinson mode coupling. In the analytic modeling, we operate an algorithm to consider Robinson instabilities. To study the evolution of unstable behavior, simulations have been performed in which macroparticles are distributed among the buckets. Both the analytic modeling and simulations agree for passive operation of the harmonic cavity.  
 
TUP003 Beam Stop of Spiral2 Facility: Activation and Residual Dose Rate Calculations 811
 
  • A. Mayoral, M. García, D. López, F. Ogando, J. Sanz, P. Sauvan
    UNED, Madrid, Spain
 
  Funding: *SPIRAL 2 Preparatory Phase. European Strategy Forum on Research Infrastructures. Seventh Framework Programme Ref 212692 **The Spanish Ministery of Science and Innovation. Project ENE2009-07572
SPIRAL2 facility is expected to produce 5mA of deuterons at 40 MeV. A beam dump device (BD) has been designed to stop the beam. In this paper we assess the residual dose rates (RDR) in the BD room during beam-off phases. MCNPX was used to deal with deuterons transport and production and transport of secondary neutrons. Deuteron and neutron induced activation were computed using ACAB* and EAF2007. Decay gammas were transported using MCNPX to compute RDR. Dose rates at cooling times up to one year are presented, showing that it is mainly due to BD copper induced activation. The uncertainties in the results can be attributed to: i) the reliability of the d-Cu activation cross sections reactions, ii) the computational approach used to assess the neutron source. The troublesome radioisotopes from d-Cu and their formation reactions were identified. EAF2007 cross sections for these reactions were compared with the available experimental data. Regarding the computational approach to determine the neutron source from d-Cu interactions two options were used: i) built-in nuclear models of MCNPX, ii) TENDL** and MCUNED***. The available experimental data were used for benchmarking.
* J. Sanz et al. ACAB. User’s manual NEA-1839 (2009)
** A.J. Koning et al. TENDL2008 http://www.talys.eu/tendl-2008/
*** P.Sauvan et al. Nucl. Instr.and Meth. A 614 (2010)3 323-330.
 
 
TUP004 GEANT4 Modelling of Heat Deposition into the ISIS Muon Target 814
 
  • A. Bungau, R. Cywinski
    University of Huddersfield, Huddersfield, United Kingdom
  • R.J. Barlow
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C. Bungau
    Manchester University, Manchester, United Kingdom
  • P.J.C. King, J.S. Lord
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
 
  The energy deposition on the ISIS muon target and the temperature profiles are analysed in this paper. The thermal modelling is performed using the GEANT4 Monte Carlo code. Heat deposition patterns are also simulated for alternative target geometries. Energy deposition in the collimators is also discussed.  
 
TUP005 Comparison of Back-scattering Properties of Electron Emission Materials 817
 
  • Z. Insepov, V. Ivanov, S.J. Jokela, M. Wetstein
    ANL, Argonne, USA
 
  We use “microscopic” Monte Carlo (MC) simulations, empirical theories, and comparison with experiments to identify the influence of back-scattered electrons and the saturation effect on the emissive properties of materials and to study the gain and transit times for various microchannel plates (MCPs). We have applied this method to Al2O3 and MgO emissive materials of various thickness and surface quality. The experimental secondary emission yield (SEY) data were obtained at normal electron impacts and were used as the reference data for adjusting our MC simulations. The SEY data were calculated at oblique angles of the primary electrons in the interval of 0-80 degrees. The energy dependence of backscattered electron coefficients (BSCs) for various primary electron incidence angles was calculated by MC for both materials, and the results were compared with experimental “average” values obtained in the literature. Both SEY and BSC data were used as input files to our “macroscopic” trajectory simulation, which models MCP amplifiers as whole devices and is capable of gain and transit time calculations.  
 
TUP008 Update on Multipactor in Coaxial Waveguides using CST Particle Studio 820
 
  • G.V. Romanov
    Fermilab, Batavia, USA
 
  CST Particle Studio combines electromagnetic field simulation, multiparticle tracking, adequate post-processing and advanced probabilistic emission model, which is the most important new capability in multipactor simulation. The emission model includes in simulation the stochastic properties of emission and adds primary electron elastic and inelastic reflection from the surfaces. The simulation of multipactor in coaxial waveguides have been performed to study the effects of the innovations on the multipactor threshold and the range over which multipactor can occur. The results compared with available previous experiments and simualtions as well as the technique of MP simulation with CST PS are presented and discussed.  
 
TUP009 A Computational Model for Muons Passing Gas and Plasma Targets: Beam Emittance. 823
 
  • A. Samolov, A.L. Godunov
    ODU, Norfolk, Virginia, USA
 
  A good understanding of interaction of muon beams with gas targets is crucial for attaining high acceleration gradients in gas pressured RF cavities. This physics includes a number of challenging problems. Our objective has been to develop a computational model for studying the most important effects within the same level of accuracy. The computational model simulates scattering of a bunch of charged particles on multiple atomic, molecular and ionic centers. The interaction potentials have been calculated using Hartree-Fock method for atomic targets, and Molecular Orbital method for molecular targets. Target particles are populated randomly to simulate either a gas in a pressured RF cavity with a particular material density, or liquid hydrogen. In the present work the following effects on beam emittance have been studied: effect of multiple scattering (comparing to single particle tracking models), effect of various degree of target ionization (beam-plasma interaction), space charge screening in plasma, effect of strong magnetic fields. Our preliminary results demonstrate that the degree of plasma ionization has a strong effect of the beam emittance.  
 
TUP010 Code TESLA for Modeling and Design of High-Power, High-Efficiency Klystrons 826
 
  • I.A. Chernyavskiy
    SAIC, McLean, USA
  • T.M. Antonsen
    UMD, College Park, Maryland, USA
  • S.J. Cooke, B. Levush, A.N. Vlasov
    NRL, Washington, DC, USA
 
  Funding: This work was supported by the U.S. Office of Naval Research (ONR).
This work gives an overview of the main features of the 2.5D large-signal code TESLA and its capabilities for the modelling single-beam and multiple-beam klystrons as high-power RF sources. These sources are widely used or proposed to be used in accelerators in the future. Comparison of TESLA modelling results with experimental data for a few multiple-beam klystrons are shown.
 
 
TUP011 Multipactor Dynamics in Dielectric-loaded Accelerator Structures 829
 
  • O.V. Sinitsyn, T.M. Antonsen, G.S. Nusinovich
    UMD, College Park, Maryland, USA
 
  Funding: This work has been supported by the Office of High Energy Physics of the U.S. Department of Energy.
In this paper the authors present results of threedimensional analysis of multipactor in dielectric-loaded accelerator structures. The studies are aimed at checking some assumptions that were used in previous two-dimensional theory. In particular, it is demonstrated that the spatial distribution of charged particles can be azimuthally non-uniform which suggests using a more complex space charge model in some cases. Also, it is shown that the particle axial velocity components can be making a substantial contribution to particle energy and should not be ignored in future studies.
 
 
TUP012 Computer Simulations of Waveguide Window and Coupler Iris for Precision Matching 832
 
  • S.W. Lee
    ORNL RAD, Oak Ridge, Tennessee, USA
  • Y.W. Kang, K.R. Shin, A.V. Vassioutchenko
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
A tapered ridge waveguide iris input coupler and a waveguide ceramic disk windows are used on each of six drift tube linac (DTL) cavities in the Spallation Neutron Source (SNS). The coupler design employs rapidly tapered double ridge waveguide to reduce the cross section down to a smaller low impedance transmission line section that can couple to the DTL tank easily. The impedance matching is done by adjusting the dimensions of the thin slit aperture between the ridges that is the coupling element responsible for the power delivery to the cavity. Since the coupling is sensitive to the dimensional changes of the aperture, it requires careful tuning for precise matching. Accurate RF simulation using latest 3-D EM code is desirable to help the tuning for maintenance and spare manufacturing. Simulations are done for the complete system with the ceramic window and the coupling iris on the cavity to see mutual interaction between the components as a whole.
 
 
TUP013 A Concept Design of a Compton Scattering Light Source based on the HLS Electron Storage Ring 835
 
  • X.C. Lai, H. Hao, H.Q. Huang, W.W. Li, X.Q. Wang, D.R. Xu
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  Funding: National Natural Science Foundation of China (Contract NO. 11045003)
Hefei Light Source (HLS) is a 2nd generation light source lasering high flux ultraviolet and soft x-ray with 200 MeV to 800 MeV electron beam. To explorer other applications of the electron storage ring of HLS, a concept design of Hefei Compton Scattering Light Source (HCSLS) is proposed. In this paper, Compton Scattring Simulation Code(CSSC), a parallel code based on the analytical method to simulate the Compton scattering between the laser beam and the electron beam, is presented. Using the CSSC, it is computed that HCSLS will produce photons with a total flux of 109 s-1 to 1011 s-1, and energy of 0.07 MeV to 1.15 MeV at the maximum spectral flux density with the 200 MeV to 800 MeV electron beam scattering with a kilo-watts CO2 laser. With a much shorter wave laser beam from an Nd:YVO4 laser, the scattered photons energy at the maximum spectral flux density is improved by a factor of 10, while its flux is reduce by a factor of 100 due to the lower peak laser power.
 
 
TUP014 Broad-band Beam Chopper for a CW Proton Linac at Fermilab 838
 
  • N. Solyak, E. Gianfelice-Wendt, V.A. Lebedev, S. Nagaitsev, D. Sun
    Fermilab, Batavia, USA
 
  The specifications and the initial conceptual ides for a broad-band proton chopper for a Fermilab Project X linac will be presented. The chopper will form bunch patterns required by physics experiments and will work with downstream beam splitter, allowing for a variable bunch pattern to be delivered to up to three experiment concurrently.  
 
TUP015 Conceptual Design of the Project-X 1.3 GHz, 3-8 GeV Pulsed Linac 841
 
  • N. Solyak, Y.I. Eidelman, S. Nagaitsev, J.-F. Ostiguy, A. Vostrikov, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  The Project-X, a multi-MW proton source, is under development at Fermilab. It enables a Long Baseline Neutrino Experiment via a new beam line pointed to DUSEL in Lead, South Dakota, and a broad suite of rare decay experiments. The facility contains 3-GeV 1-mA CW superconducting linac. In the second stage of about 5% of the H beam is accelerated up to 8 GeV in a 1.3 GHz SRF pulse linac to Recycler/Main Injector. In order to mitigate the problem with the stripping foil heating during injection to the Main Injector, the pulses with higher current are accelerated in CW linac together with 1 mA beam for further acceleration in the pulse linac. The optimal current in the pulse linac is discussed as well as limitations that determine it's selection. A concept design of the pulse linac is described. The lattice design is presented as well as RF stability analysis. The necessity of the HOM couplers is discussed also.  
 
TUP016 Beam Brightness Booster with Charge Exchange Injection and Superintense Circulating Beams Production 844
 
  • V.G. Dudnikov, C.M. Ankenbrandt
    Muons, Inc, Batavia, USA
 
  An increase of intensity and brightness of proton beam by means of charge exchange injection and devices developed for this experiment are considered. First observation of e-p instability, explanation and damping by feed back are discussed. Discovery of “cesiation effect” leading to multiple increase of negative ion emission from gas discharges and development of surface-plasma sources for intense high brightness negative ion beams production are considered. By these developments were prepared a possibility for production of stable “superintense” circulating beam with intensity and brightness fare above space charge limit. A beam brightness booster (BBB) for significant increase of accumulated beam brightness is discussed. New opportunity for simplification of the superintense beam production is promised by developing of nonlinear close to integrable focusing system with broad spread of betatron tune and the broad bend feed back system for e-p instability suppression.  
 
TUP017 Conceptual Design for the ARIEL 300 keV Electron Gun 847
 
  • C.D. Beard, F. Ames, S. Austen, R.A. Baartman, Y.-C. Chao, K. Fong, C. Gong, N. Khan, S.R. Koscielniak, A. Laxdal, R.E. Laxdal, C.D.P. Levy, D. Louie, J. Lu, L. Merminga, A.K. Mitra, D. Rowbotham, P. Vincent, D. Yosifov
    TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
  • C.K. Sinclair
    CLASSE, Ithaca, New York, USA
 
  The Advanced Rare Isotope Laboratory (ARIEL) at TRIUMF is a facility that will augment existing programs at ISAC. ARIEL was funded in July 2010. Products from the complementary methods of proton-driven and bremsstrahlung-driven fission will be available for nuclear and materials science. Equipment for the photofission driver is the subject of this paper: a high-intensity electron beam provided by a high-voltage electron source (or e-gun) will be accelerated in a superconducting linear accelerator, and guided to a γ-ray convertor and actinide target assembly. The electron source is a 10 mA 300 keV thermionic gun, with a control grid for modulation of the beam. This paper describes the conceptual design of the gun, and highlights some of the progress made in the engineering design. First beam from the gun is anticipated in early 2012.  
 
TUP018 Design of a S-Band 4,5 Cells RF Gun 850
 
  • R. Roux, C. Bruni, H. Monard
    LAL, Orsay, France
 
  Most of radio-frequency (RF) photo-injectors operating in the world are made of 1,5 or 2,5 cells. Although excellent qualities of electron beam have been obtained there are few cases where the extension of the number of cells could be interesting. For instance, the small accelerators with energy in the range of 10-20 MeV which are mostly based on the operation of a RF gun with a booster. One single RF gun fulfilling both functions would simplify the construction and the cost of such machines. The inherent simplicity would also ensure a better reliability. We will present 2D and 3D RF simulations of this 4,5 cells RF photo-injector. In addition we will compare through beam dynamics simulations, with the PARMELA and ASTRA codes, the performances of this gun with respect of classical design based on the couple RF gun plus booster.  
 
TUP019 The S-DALINAC Polarized Injector SPIN - Performance and Results 853
 
  • C. Eckardt, T. Bahlo, P. Bangert, R. Barday, U. Bonnes, M. Brunken, C. Burandt, R. Eichhorn, J. Enders, M. Espig, C. Ingenhaag, J. Lindemann, M. Platz, Y. Poltoratska, M. Roth, F. Schneider, H. Schüßler, M. Wagner, A. Weber, B. Zwicker
    TU Darmstadt, Darmstadt, Germany
  • W. Ackermann, W.F.O. Müller, T. Weiland
    TEMF, TU Darmstadt, Darmstadt, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
 
  Funding: * Work supported by DFG through SFB 634.
At the superconducting 130 MeV Darmstadt electron linac S-DALINAC the new source of polarized electrons uses a GaAs cathode illuminated with pulsed Ti:Sapphire and diode laser light. The electron source had been set up and commissioned at a test stand with a beam line where a Wien filter for spin manipulation, a Mott polarimeter for polarization measurement and a chopper-prebuncher system were part of the system. Upon completion of the tests, test stand and beam line were dismantled and re-installed at the S-DALINAC. The new photo injector opens up the potential for experiments with polarized electron and photon beams for nuclear structure studies at low momentum transfers. Various polarimeters will be installed at all experimental sites to monitor the beam polarization. We report on the S-DALINAC, the results from the teststand performance, the implementation of the polarized source and the polarimeter research and development.
* A. Richter, Proc. of the 5th EPAC, Sitges (1996) 110
** Y. Poltoratska et al., AIP Conference Proc. 1149 (2009) 983
*** P. Mohr et al., Nucl. Instr. and Meth. A423 (1999) 480
 
 
TUP020 A New Continuous Muon Beam Line Using a Highly Efficient Pion Capture System at RCNP 856
 
  • H. Sakamoto, Y. Kuno, A. Sato
    Osaka University, Osaka, Japan
  • S. Cook, R.T.P. D'Arcy
    UCL, London, United Kingdom
  • M. Fukuda, K. Hatanaka
    RCNP, Osaka, Japan
  • T. Ogitsu, A. Yamamoto, M.Y. Yoshida
    KEK, Ibaraki, Japan
 
  A new muon source with continuous time structure is under construction at Research Center of Nuclear Physics (RCNP), Osaka University. The ring cyclotron of RCNP can provide 400W 400MeV proton beam. Using this proton beam, the MuSIC produces a high intense muon beam. The target muon intensity is 108 muons/second, which is achieved by a pion capture with great efficiency to collect pions and muons using a solenoidal magnetic field. A pion production target system is located in a 3.5 Tesla solenoidal magnetic field generated by a super-conducting solenoid magnet. The proton beam hits the target, and backward pions and muons are captured by the field. Then they are transported by a curved solenoid beam line to experimental apparatus. The construction has been started in 2010, and would be finished in 5 years. We plan to carry out not only an experiment to search the lepton flavor violating process but also other experiments for muon science and their applications using the intense muon beam.  
 
TUP023 X-Band RF Photoinjector Research and Development at LLNL 859
 
  • R.A. Marsh, S.G. Anderson, C.P.J. Barty, G.K. Beer, R.R. Cross, G.A. Deis, C.A. Ebbers, D.J. Gibson, F.V. Hartemann, T.L. Houck
    LLNL, Livermore, California, USA
  • C. Adolphsen, A.E. Candel, T.S. Chu, E.N. Jongewaard, Z. Li, C. Limborg-Deprey, T.O. Raubenheimer, S.G. Tantawi, A.E. Vlieks, F. Wang, J.W. Wang, F. Zhou
    SLAC, Menlo Park, California, USA
 
  Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, and funded by DHS Domestic Nuclear Detection Office
In support of Compton scattering gamma-ray source efforts at LLNL, a multi-bunch test station is being developed to investigate accelerator optimization for future upgrades. This test station will enable work to explore the science and technology paths required to boost the current mono-energetic gamma-ray (MEGa-Ray) technology a higher effective repetition rate, potentially increasing the average gamma-ray brightness by two orders of magnitude. The test station will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. Beam quality must be exceedingly high in order to produce narrow-bandwidth gamma-rays, requiring a robust state of the art photoinjector. The photoinjector will be a high gradient (200 MV/m cathode field) standing wave structure, featuring a dual feed racetrack coupler, elliptical irises, and an optimized first cell length. Detailed design of the rf photoinjector for this test station is complete, and will be presented with modeling simulations, and layout plans.
 
 
TUP025 Two Wien Filter Spin Flipper 862
 
  • J.M. Grames, P.A. Adderley, J. F. Benesch, J. Clark, J. Hansknecht, R. Kazimi, D. Machie, M. Poelker, M.L. Stutzman, R. Suleiman, Y. Zhang
    JLAB, Newport News, Virginia, USA
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A new 4pi spin manipulator composed of two Wien filters oriented orthogonally and separated by two solenoids has been installed at the CEBAF/Jefferson Lab photoinjector. The new spin manipulator is used to precisely set the electron spin direction at an experiment in any direction (in or out of plane of the accelerator) and provides the means to reverse, or flip, the helicity of the electron beam on a daily basis. This reversal is being employed to suppress systematic false asymmetries that can jeopardize challenging parity violation experiments that strive to measure increasingly small physics asymmetries [*,**,***]. The spin manipulator is part of the ultra-high vacuum polarized electron source beam line and has been successfully operated with 100keV and 130keV electron beam at high current (>100 microAmps). A unique feature of the device is that spin-flipping requires only the polarity of one solenoid magnet be changed. Performance characteristics of the Two Wien Filter Spin Flipper will be summarized.
* http://hallaweb.jlab.org/parity/prex/
** http://www.jlab.org/qweak/
*** http://hallaweb.jlab.org/12GeV/Moller/
 
 
TUP029 Low-Beta Superconducting RF Cavity Tune Options 865
 
  • E.N. Zaplatin
    FZJ, Jülich, Germany
 
  The main method of the superconducting RF cavity frequency tuning is a resonator wall deformation. Since the highest frequency sensitivity on the geometry change is an accelerating gap variation, the "standard" place of deformation tuning force application in different cavity types are the cavity beam ports. A series of low-beta cavities (QWR, HWR, spoke-type) with different options of tuning have been investigated. Every option is compared with beam port displacement. The problem of resonator frequency shift self-compensation caused by external pressure fluctuations is discussed.  
 
TUP031 Project X Elliptical Cavity Structural Analyses 868
 
  • E.N. Zaplatin
    FZJ, Jülich, Germany
 
  Project X is proposed at Fermi National Accelerator Laboratory high-intensity proton accelerator complex that could provide beam for a variety of physics projects. Superconducting resonators will be used for beam acceleration. Here we report a structural design of elliptical cavities with resonance frequency 650 MHz and β=0.91 and 0.61. Since there is a concern that the pressure in the helium plumbing will not be stable when the cryomodules are connected to the liquid helium supply and helium gas returns it is necessary to provide the cavity stiffening with requirements of 15 Hz amplitude frequency shift. The cavity RF and mechanical properties are investigated. The calculations of the cavity frequency shift with pressure for different schemes of cavity stiffening were provided. The criterion for the optimization was the minimization of a resonant frequency dependence on an external pressure. Based on the results of these simulations several options on cavity stiffening have been proposed. Additionally, the cavity stiffening structural scheme for self-compensation of resonator detuning caused by external pressure fluctuation have been investigated.  
 
TUP032 Development of 1.3 GHz Prototype Niobium Single Cell Superconducting Cavity Under IIFC Collaboration 871
 
  • A. Puntambekar, M. Bagre, J. Dwivedi, P.D. Gupta, R.K. Gupta, S.C. Joshi, G.V. Kane, R.S. Sandha, S.D. Sharma, P. Shrivastava
    RRCAT, Indore (M.P.), India
  • C.A. Cooper, M.H. Foley, T.N. Khabiboulline, C.S. Mishra, J.P. Ozelis, A.M. Rowe, G. Wu
    Fermilab, Batavia, USA
  • V. Jain
    IIT, Mumbai, India
  • D. Kanjilal, K.K. Mistri, P.N. Potukuchi, J. Sacharias
    IUAC, New Delhi, India
  • V.C. Sahni
    Homi Bhbha National Institute (HBNI), DAE, Mumbai, India
 
  Under Indian Institutions Fermilab collaboration (IIFC), Raja Ramanna Centre for Advanced Technology (RRCAT) Indore, Inter University Accelerator Centre (IUAC) New Delhi and Fermi National Accelerator Laboratory (FNAL) have developed two prototype 1.3 GHz niobium single cell superconducting cavities. Development of forming tools, forming of half cells, machining of components, development of welding fixtures along with RF & vacuum qualification were carried out at RRCAT. The electron beam welding was carried out at IUAC. The fabricated prototype cavities were tested for RF and vacuum leak tightness up to 77 K at RRCAT before shipment to FNAL. Processing, consisting of CBP, EP, and heat treatment was carried out jointly by FNAL and Argonne National Laboratory in USA. Both the prototype cavities were tested at 2 K in the VTS facility at FNAL and have achieved the accelerating gradient of ~ 19 to 21 MV/m with Q > 1.5 ·10+10. This paper will report the developmental efforts carried out in tooling, forming, machining, welding & various qualification procedures adopted. The paper will also present the processing and the 2 K test results.  
 
TUP033 Engineering Design of Vertical Test Stand Cryostat 874
 
  • S.K. Suhane, S. Das, P.D. Gupta, S.C. Joshi, P.K. Kush, S. Raghvendra, N.K. Sharma
    RRCAT, Indore (M.P.), India
  • R.H. Carcagno, C.M. Ginsburg, C.S. Mishra, J.P. Ozelis, R. Rabehl, C. Sylvester
    Fermilab, Batavia, USA
  • V.C. Sahni
    Homi Bhbha National Institute (HBNI), DAE, Mumbai, India
 
  Under Indian Institutions and Fermilab collaboration Raja Ramanna Centre for Advanced Technology and Fermi Lab are jointly developing 2K Vertical Test Stand (VTS) cryostats for testing SCRF cavities. The VTS cryostat has been designed for a large testing aperture of 34 inches for testing of 325 MHz Spoke resonators, 650 MHz and 1.3 GHz multi-cell SCRF cavities for Project-X at FNAL and for VTS facility at RRCAT. VTS cryostat comprises of liquid helium (LHe) vessel with internal magnetic shield, top insert plate equipped with cavity support stand and radiation shield, liquid nitrogen (LN2) shield and vacuum vessel with external magnetic shield. . The engineering design and analysis of VTS cryostat has been carried out using ASME B&PV code and FEA. Design of internal and external magnetic shields was performed to limit the magnetic field inside LHe vessel, at the cavity surface <10 mG. Thermal analysis for LN2 shield has been performed to check the effectiveness of LN2 cooling.  
 
TUP039 Low Latency Data Transmission in LLRF Systems 877
 
  • D.R. Makowski, G.W. Jabłoński, A. Napieralski, P. Predki
    TUL-DMCS, Łódź, Poland
 
  Funding: The research leading to these results has received funding from the Polish National Science Council Grant 642/N-TESLAXFEL/09/2010/0.
The linear accelerators applied to drive Free Electron Lasers (FELs), such as the X-Ray Free Electron Laser (XFEL), require sophisticated control systems. The Low Level Radio Frequency (LLRF) control systems of a linear accelerator should provide signal to vector modulator in less than 1 microsecond. Therefore the latency of communication interfaces is more important than their throughput. The paper discusses the application of serial gigabit links for transmission of data in LLRF systems. The latency of pure serial transmission based on Xilinx RocketIO transceivers was evaluated and compared with Xilinx Aurora protocol. The developed low latency protocol will be also presented.
 
 
TUP040 Asset Management Application for a LLRF Control System 880
 
  • B. Sakowicz, M. Kamiński, D.R. Makowski, P. Mazur, A. Napieralski, A. Piotrowski
    TUL-DMCS, Łódź, Poland
 
  Funding: The research leading to these results has received funding from the Polish National Science Council Grant 642/N-TESLAXFEL/09/2010/0.
In this article an asset management application for a low level radio frequency (LLRF) control system is described. The system was developed to facilitate management of some aspects of controlling a linear accelerator and, among others, provides means to manage and program multiple firmware versions for a large, distributed and frequently changing set of FPGA devices that are present in a control system. The system introduces a multihierarchical tree-based representation of almost all assets involved in accelerator management.*
* Kamiński M., Makowski D., Mazur P., Murlewski J., Sakowicz B.: "Firmware application for LLRF control system based on the Enterprise Service Bus", CADSM 2009, Ukraine, ISBN 978-966-2191-05-9
 
 
TUP041 Quench Dynamics in SRF Cavities: Can We Locate the Quench Origin with 2nd Sound? 883
 
  • Y.B. Maximenko
    MIPT, Dolgoprudniy, Moscow Region, Russia
  • D.A. Sergatskov
    Fermilab, Batavia, USA
 
  A newly developed method of locating quench in SRF cavities by detecting second-sound waves has been gaining popularity in SRF laboratories. The technique is based on measurements of time delays between the quench, as determined by the RF system, and arrival of the 2nd sound wave to the multiple detectors placed around the cavity in superfluid helium. Unlike multi-channel temperature mapping, this approach requires only few sensors and simple readout electronics; it can be used with SRF cavities of almost arbitrary shape. One of its drawbacks is that being an indirect method it requires one to solve an inverse problem to find a location of a quench. We tried to solve this inverse problem by using a parametric forward model. By analyzing the data we found that a simple model where 2nd-sound emitter is a near-singular source does not describe the physical system well enough. A time-dependent analysis of a quench process can help us to put forward a more adequate model. We present here our current algorithm to solve the inverse problem and discuss the experimental results.  
 
TUP042 RF Measurements and Numerical Simulations for the Model of the Bilbao Linac Double Spoke Cavity 886
 
  • J.L. Munoz, I. Bustinduy, N. Garmendia, V. Toyos
    ESS Bilbao, Bilbao, Spain
  • E. Asua
    UPV-EHU, Leioa, Spain
  • F.J. Bermejo
    Bilbao, Faculty of Science and Technology, Bilbao, Spain
  • V. Etxebarria, J. Portilla
    University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
  • J. Feuchtwanger
    ESS-Bilbao, Zamudio, Spain
  • J. Lucas
    Elytt Energy, Madrid, Spain
 
  A model of a double spoke resonant cavity (operating frequency 352.2 MHz, βg=0.39) has been designed and fabricated in aluminium. The RF characteristics of the cavity have been measured in our laboratory. Experimental measurements have involved the determination of the main cavity parameters, and the characterization of the accelerating electric field profile along the cavity axis by means of a fully automated bead-pullmethod. Additionally, numerical simulations using COMSOL code have been used to fully characterize the cavity. Electromagnetic numerical simulations of the cavity have been also performed to determine its main figures of merit and to identify the most suitable position for opening a port to install a power coupler. In this paper we report the cavity cold model description, the experimental setup and corresponding techniques, together with the numerical methods. The obtained results are described and discussed in detail.  
 
TUP044 A Comparison of Superconducting RF Structures Optimized for β = 0.285 889
 
  • Z.A. Conway, R.L. Fischer, M.P. Kelly, A. Kolomiets, B. Mustapha, P.N. Ostroumov
    ANL, Argonne, USA
 
  Recent advances in low-beta superconducting RF technology have enabled the proposal and construction of ever-increasing-intensity ion accelerators, e.g. The Facility for Rare Isotope Beams (FRIB) at Michigan State University and Project-X at Fermilab. Superconducting TEM-class structures are required for these accelerators and beam quality preservation and cost efficiency are of the highest importance. This paper presents a comparison of the superconducting TEM-class cavities available for the acceleration of ions in the energy range of 16 to 55 MeV/u in order to guide their selection in future ion accelerator projects.  
 
TUP046 Superconducting 72 MHz β=0.077 Quarter-wave Cavity for ATLAS 892
 
  • M.P. Kelly, Z.A. Conway, S.M. Gerbick, M. Kedzie, R.C. Murphy, P.N. Ostroumov, T. Reid
    ANL, Argonne, USA
 
  A 72 MHz superconducting (SC) niobium quarter-wave cavity (QWR) optimized for β=0.077 has been built and tested as part of a beam intensity upgrade of the ATLAS SC heavy-ion linac. The two-gap cavity, designed to accelerate ions over the velocity range 0.06<β<0.12 and provide 2.5 MV of accelerating voltage per cavity at T=4.5 Kelvin, is based on a highly optimized electromagnetic design to reduce surface electric and magnetic fields. Horizontal electropolishing on the complete cavity with the helium jacket, is similar to that performed on 1.3 GHz ILC-type cavities and is a first for a low-β TEM cavity. This development is part of a broader effort to demonstrate ~120 mT surface fields with Rs~5 nΩ in 2 K operation for low-β cavities with the aim of substantially reducing the footprint for future ion linacs. First rf cold test results show the highest accelerating gradients (13.4 MV/m, leff=βλ) and voltage/cavity (4.3 MV) achieved for this class of SC cavity.  
 
TUP049 Vacuum Arcs and Gradient Limits 895
 
  • J. Norem, Z. Insepov
    ANL, Argonne, USA
  • A. Moretti
    Fermilab, Batavia, USA
 
  Funding: DOE/OHEP
We have been extending and refining our model of vacuum breakdown and gradient limits and will describe recent developments. The model considers a large number of mechanisms but finds that vacuum arcs can be described fairly simply and self consistently, however simulations of individual mechanisms can be, in some cases, involved. Although based on accelerator rf data, we believe our model of vacuum arcs should have general applicability.
 
 
TUP051 Design and First Cold Test of BNL Superconducting 112 MHz QWR for Electron Gun Applications 898
 
  • S.A. Belomestnykh, I. Ben-Zvi, X. Chang, R. Than
    BNL, Upton, Long Island, New York, USA
  • C.H. Boulware, T.L. Grimm, B. Siegel, M.J. Winowski
    Niowave, Inc., Lansing, Michigan, USA
 
  Brookhaven National Laboratory and Niowave, Inc. have designed, fabricated, and performed the first cold test of a superconducting 112 MHz quarter-wave resonator (QWR) for electron gun experiments. The first cold test of the QWR cryomodule has been completed at Niowave. The paper discusses the cryomodule design, presents the cold test results, and outline plans to upgrade the cryomodule for future experiments.
Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. The work at Niowave is supported by the U.S. DOE under SBIR contract No. DE-FG02-07ER84861
 
 
TUP052 HOM Damping Properties of Fundamental Power Couplers in the Superconducting Electron Gun of the Energy Recovery LINAC at Brookhaven National Laboratory 901
 
  • L.R. Hammons, H. Hahn
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Among the accelerator projects under construction at the Relativistic Heavy Ion Collider (RHIC) is an R&D energy recovery LINAC (ERL) test facility. The ERL includes both a five-cell superconducting cavity as well as a superconducting, photoinjector electron gun. Because of the high-charge and high-current demands, effective higher-order mode (HOM) damping is essential, and several strategies are being pursued. Among these is the use of the fundamental power couplers as a means for damping some HOMs. Simulation studies have shown that the power couplers can play a substantial role in damping certain HOMs, and this presentation will discuss these studies along with measurements.
 
 
TUP053 Ferrite HOM Load Surrounding a Ceramic Break 904
 
  • L.R. Hammons, H. Hahn
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Several future accelerator projects at the Relativistic Heavy Ion Collider are being developed using a super-conducting electron energy recovery LINAC along with a superconducting electron gun as the source. All of the projects involve high-current, high-charge operation and require effective higher-order mode (HOM) damping to achieve the performance objectives. Among the HOM designs being developed is a waveguide-type HOM load for the electron gun consisting of a ceramic break surrounded by ferrite tiles. This design is innovative in its approach and achieves a variety of ends including broadband HOM damping and protection of the superconducting cavity from potential damage to the ferrite tiles. Furthermore, the ceramic is an effective thermal transition. This design may be useful in various applications since it readily allows for replacement of the ferrite tiles with other materials and may also be useful for testing the absorbing properties of these materials. In this paper, the details of the design will be discussed along with current modelling and testing results as well as future plans.
 
 
TUP054 Mechanical Design of 56 MHz Superconducting RF Cavity for RHIC Collider 907
 
  • C. Pai, I. Ben-Zvi, A. Burrill, X. Chang, G.T. McIntyre, R. Than, J.E. Tuozzolo, Q. Wu
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A 56 MHz Superconducting RF Cavity operating at 4.4K is being constructed for the RHIC collider. This cavity is a quarter wave resonator with beam transmission along the centreline. This cavity will increase collision luminosity by providing a large longitudinal bucket for stored bunches of RHIC ion beam. The major components of this assembly are the niobium cavity with the mechanical tuner, its titanium helium vessel and vacuum cryostat, the support system, and the ports for HOM and fundamental dampers. The cavity and its helium vessel must meet the ASME pressure vessel code and it must not be sensitive to frequency shift due to pressure fluctuations from the helium supply system. Frequency tuning achieved by a two stage mechanical tuner is required to meet performance parameters. This tuner mechanism pushes and pulls the tuning plate in the gap of niobium cavity. The tuner mechanism has two separate drive systems to provide both coarse and fine tuning capabilities. This paper discusses the design detail and how the design requirements are met.
 
 
TUP055 Design and Preliminary Test of the 1500 MHz NSLS-II Passive Superconducting RF Cavity 910
 
  • J. Rose, W.K. Gash, B.N. Kosciuk, V. Ravindranath, S.K. Sharma, R. Sikora, N.A. Towne
    BNL, Upton, Long Island, New York, USA
  • C.H. Boulware, T.L. Grimm, C. Krizmanich, B. Kuhlman, N. Miller, B. Siegel, M.J. Winowski
    Niowave, Inc., Lansing, Michigan, USA
 
  NSLS-II is a new ultra-bright 3 GeV 3rd generation synchrotron radiation light source. The performance goals require operation with a beam current of 500mA and a bunch current of at least 0.5mA. Ion clearing gaps are required to suppress ion effects on the beam. The natural bunch length of 3mm is planned to be lengthened by means of a third harmonic cavity in order to increase the Touschek limited lifetime. Earlier work described the design alternatives and the geometry selected for a copper prototype. We subsequently have iterated the design to lower the R/Q of the cavity and to increase the diameter of the beam pipe ferrite HOM dampers to reduce the wakefield heating. A niobium cavity and full cryomodule including LN2 shield, magnetic shield and insulating vacuum vessel have been fabricated and installed.  
 
TUP056 BNL 703 MHz Superconducting RF Cavity Testing 913
 
  • B. Sheehy, Z. Altinbas, I. Ben-Zvi, D.M. Gassner, H. Hahn, L.R. Hammons, J.P. Jamilkowski, D. Kayran, J. Kewisch, N. Laloudakis, D.L. Lederle, V. Litvinenko, G.T. McIntyre, D. Pate, D. Phillips, C. Schultheiss, T. Seda, R. Than, W. Xu, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • A. Burrill
    JLAB, Newport News, Virginia, USA
  • T. Schultheiss
    AES, Medford, NY, USA
 
  Funding: This work received support from Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The Brookhaven National Laboratory (BNL) 5-cell, 703 MHz superconducting RF accelerating cavity has been installed in the high-current energy recovery linac (ERL) experiment. This experiment will function as a proving ground for the development of high-current machines in general and is particularly targeted at beam development for an electron-ion collider (eRHIC). The cavity performed well in vertical tests, demonstrating gradients of 20 MV/m and a Q0 of 1010. Here we will present its performance in the horizontal tests, and discuss technical issues involved in its implementation in the ERL.
 
 
TUP057 The Fundamental Power Coupler and Pick-up of the 56 MHz Cavity for RHIC 916
 
  • Q. Wu, S. Bellavia, I. Ben-Zvi, C. Pai
    BNL, Upton, Long Island, New York, USA
 
  Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
A fundamental power coupler (FPC) is designed to obtain the ability of fast tuning the 56MHz SRF cavity in RHIC. The FPC will be inserted from one of the chemical cleaning ports at the rear end of the cavity with magnetic coupling to the RF field. The size and the location of the FPC are decided based on the required operational external Q of the cavity. The FPC is designed with variable coupling that would cover a range of power levels, and it is thermally isolated from the base temperature of the cavity, which is 4.2K. A 1kW power amplifier will also be used to close an amplitude control feedback loop. In this paper, we discuss the coupling factor of the FPC with the carefully chosen design, as well as the thermal issues.
 
 
TUP058 Fundamental Damper Power Calculation of the 56MHz SRF Cavity for RHIC 919
 
  • Q. Wu, S. Bellavia, I. Ben-Zvi, M.C. Grau, G. Miglionico, C. Pai
    BNL, Upton, Long Island, New York, USA
 
  Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
At each injection and extraction period of RHIC operation, the beam frequency will be sweeping across a wide range, and some of the harmonics will cross the frequency of the 56MHz SRF cavity. To avoid cavity excitation during these periods, a fundamental damper was designed for the quarter-wave resonator to heavily detune the cavity. The power extracted by the fundamental damper should be compliant with the cooling ability of the system at all stages. In this paper, we discussed the power output from the fundamental damper when it is fully extracted, inserted, and during its movement.
 
 
TUP059 Multipacting in a Grooved Choke Joint at SRF Gun for BNL ERL Prototype 922
 
  • W. Xu, S.A. Belomestnykh, I. Ben-Zvi, A. Burrill, D. Kayran, G.T. McIntyre, B. Sheehy
    BNL, Upton, Long Island, New York, USA
  • D. Holmes
    AES, Medford, NY, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The 703 MHz superconducting gun for BNL ERL prototype was tested at JLab with and without choke-joint and cathode stalk. Without choke-joint and cathode stalk, the gradient reached 25MV/m with Q0~6·109. The gun cathode insertion port is equipped with a choke joint with triangular grooves for multipacting suppression. We carried out tests with choke-joint and cathode stalk. The test results show that there are at least two barriers at about 5MV/m and 3.5 MV/m. We considered several possibilities and finally found that the limitation was because the triangular grooves were rounded after BCP, which caused strong multipacting in the choke-joint. This paper presents the primary test result of test results of the gun and discusses the multipacting analysis in the choke-joint. It also suggests possible solutions for the gun and multipacting suppressing for a similar structure.
 
 
TUP060 New HOM Coupler Design for High Current SRF Cavity 925
 
  • W. Xu, S.A. Belomestnykh, I. Ben-Zvi, H. Hahn, E.C. Johnson
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Damping higher order modes (HOMs) significantly to avoid beam instability is a challenge for the high current Energy Recovery Linac-based eRHIC at BNL. To avoid the overheating effect and high tuning sensitivity, current, a new band-stop HOM coupler is being designed at BNL. The new HOM coupler has a bandwidth of tens of MHz to reject the fundamental mode, which will avoid overheating due to fundamental frequency shifting because of cooling down. In addition, the S21 parameter of the band-pass filter is nearly flat from first higher order mode to 5 times the fundamental frequency. The simulation results showed that the new couplers effectively damp HOMs for the eRHIC cavity with enlarged beam tube diameter and two 120° HOM couplers at each side of cavity. This paper presents the design of HOM coupler, HOM damping capacity for eRHIC cavity and prototype test results.
 
 
TUP061 FPC Conditioning Cart at BNL 928
 
  • W. Xu, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, A. Burrill, S. Deonarine, D.M. Gassner, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, L. Masi, G.T. McIntyre, D. Pate, D. Phillips, T. Seda, A.N. Steszyn, T.N. Tallerico, R.J. Todd, D. Weiss, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • M.D. Cole, G.J. Whitbeck
    AES, Medford, NY, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The 703MHz superconducting gun will have 2 fundamental power couplers (FPCs). Each FPC will deliver up to 500kW of RF power. In order to prepare the couplers for high power RF service and process multipacting, the FPCs should be conditioned before they are installed in the gun. A conditioning cart based test stand, which includes a vacuum pumping system, controllable bake-out system, diagnostics, interlocks and data log system has been designed, constructed and commissioned by collaboration of BNL and AES. This paper presents FPC conditioning cart systems and summarizes the conditioning process and results.
 
 
TUP062 Design of Coupler for the NSLS-II Storage Ring Superconducting RF Cavity 931
 
  • M. Yeddulla, J. Rose
    BNL, Upton, Long Island, New York, USA
 
  NSLS-II requires four superconducting cavities working at 499.68 MHz. These cavities should support a 500 mA beam current. To operate the cavities in over-damped coupling condition, an External Quality Factor (Qext) of ~ 65000 is required. We have modified the existing coupler for the CESR-B cavity which has a Qext of ~ 200,000 to meet the requirements of NSLS-II. CESR-B cavity has an aperture coupler with a coupler "tongue" connecting the cavity to the waveguide. We have optimized the length, width and thickness of the "tongue" as well as the width of the aperture to increase the coupling using the three dimensional electromagnetic field solver, HFSS. Several possible designs will be presented.  
 
TUP063 HOM Measurements with Beam at the Cornell Injector Cryomodule 934
 
  • S. Posen, M. Liepe
    CLASSE, Ithaca, New York, USA
 
  Funding: NSF
The Cornell ERL injector prototype is undergoing commissioning and testing for running unprecedented currents in an electron cw injector. This paper discusses preliminary measurements of HOMs in the injector prototype’s superconducting RF cryomodule. These include HOM spectra up to 30 GHz measured via small antennae located at the HOM beam line absorbers between the SRF cavities. The spectra are compared at different beam currents and repetition rates. The shape of the spectra are compared to ABCI simulations of the loss factor spectrum of the cryomodule beam line. The total HOM power dissipated in the HOM loads was also measured with beam on, which allowed for an estimate of the loss factor. This measurement was accomplished via temperature sensors on the loads, calibrated to input power by heaters on the loads.
 
 
TUP064 Designing Multiple Cavity Classes for the Main Linac of Cornell's ERL 937
 
  • N.R.A. Valles, M. Liepe
    CLASSE, Ithaca, New York, USA
 
  Funding: Work supported by NSF Grant No. PHY-0131508, and NSF/NIH-NIGMS Grant No. DMR-0937466
Cornell is currently developing a high current Energy Recovery Linac. The baseline 7-cell cavity design for the main linac has already been completed, and prototyping has begun, as of Fall 2010. Previous work showed that increasing the relative cavity-to-cavity frequency spread increases the beam break-up current through the linac. Simulations show that expected machining variations will introduce a relative HOM frequency spread of 0.5·10-3, corresponding to 150 mA of threshold current. The key idea of this work is to increase the relative cavity-to-cavity frequency spread by designing several classes of 7-cell cavities obtained by making small changes to the baseline center cell shape. This allows a threshold current in excess of 450 mA, which is well above the 100 mA goal for the Cornell Energy Recovery Linac.
 
 
TUP066 Three-cell Traveling-wave Superconducting Test Structure 940
 
  • P.V. Avrakhov, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S. Kazakov, N. Solyak, G. Wu, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Use of a superconducting traveling wave accelerating (STWA) structure* with a small phase advance per cell rather than a standing wave structure may provide a significant increase of the accelerating gradient in the ILC linac. For the same surface electric and magnetic fields the STWA achieves an accelerating gradient 1.2 larger than TESLA-like standing wave cavities. The STWA allows also longer acceleration cavities, reducing the number of gaps between them. However, the STWA structure requires a SC feedback waveguide to return the few hundreds of MW of circulating RF power from the structure output to the structure input. A test single-cell cavity with feedback was designed, manufactured and successfully tested** demonstrating the possibility of a proper processing to achieve a high accelerating gradient. These results open the way to take the next step of the TW SC cavity development: to build and test a traveling-wave three-cell cavity with a feedback waveguide. The latest results of the single-cell cavity tests are discussed as well as the design of the test 3-cell TW cavity.
* P. Avrakhov, et al, Phys. of Part. and Nucl. Let, 2008, Vol. 5, No. 7, p. 597
** G. Wu, et al, IPAC 2010, THPD048
 
 
TUP069 Status of the Mechanical Design of the 650 MHz Cavities for Project X 943
 
  • S. Barbanotti, M.S. Champion, M.H. Foley, C.M. Ginsburg, I.G. Gonin, C.J. Grimm, T.J. Peterson, L. Ristori, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  In the high-energy section of the Project X Linac, acceleration of H- ions takes place in superconducting cavities operating at 650 MHz. Two families of five-cell elliptical cavities are planned: β = 0.61 and β = 0.9. A specific feature of the Project X Linac is low beam loading, and thus, low bandwidth and higher sensitivity to microphonics. Efforts to optimize the mechanical design of the cavities to improve their mechanical stability in response to the helium bath pressure fluctuations will be presented. These efforts take into account constraints such as cost and ease of fabrication. Also discussed will be the overall design status of the cavities and their helium jackets.  
 
TUP070 EM Design of the Low-Beta SC Cavities for the Project X Front End 946
 
  • I.G. Gonin, S. Barbanotti, P. Berrutti, L. Ristori, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  The low-energy part of the Project X H-linac includes three types of superconducting single spoke cavities (SSR) with β = 0.11, 0.21 and 0.4 operating at the fundamental TEM-mode at 325MHz. In this paper we present the detailed EM optimization of cavity shapes having the goal to minimize the peak electric and magnetic fields. We also discuss the importance of the integration of EM and mechanical design.  
 
TUP071 High Power Tests of Dressed Superconducting 1.3 GHz RF Cavities 949
 
  • A. Hocker, E.R. Harms, A. Lunin, A.I. Sukhanov
    Fermilab, Batavia, USA
 
  Funding: U.S. Department of Energy, Contract No. DE-AC02-07CH11359
A single-cavity test cryostat is used to conduct pulsed high power RF tests of superconducting 1.3 GHz RF cavities at 2 K. The cavities under test are welded inside individual helium vessels and are outfitted (“dressed”) with a fundamental power coupler, higher-order mode couplers, magnetic shielding, a blade tuner, and piezoelectric tuners. The cavity performance is evaluated in terms of accelerating gradient, unloaded quality factor, and field emission, and the functionality of the auxiliary components is verified. Test results from the first set of dressed cavities are presented here.
 
 
TUP072 High Power Couplers for Project X Linac 952
 
  • S. Kazakov, M.S. Champion, M. Kramp, Y. Orlov, O. Pronitchev, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Project X, a multi-megawatt proton sources is under development in Fermi National Accelerator Laboratory. The key element of the project is a superconducting (SC) 3GV CW proton liner accelerator (linac). The linac includes 5 types of SC accelerating cavities of three 325 and 650 MHz frequencies. The cavities consumes up to 30 kW average RF power and need proper main couplers. Requirements and approach to the coupler design are discussed in the report. New cost effective schemes of the couplers are described. Results of electrodynamics and thermal simulations are presented.  
 
TUP073 Development of an L-band Ferroelectric Phase Shifter 955
 
  • S. Kazakov, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
  • J.L. Hirshfield
    Yale University, Physics Department, New Haven, CT, USA
  • A. Kanareykin, E. Nenasheva
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S.V. Shchelkunov
    Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
 
  Effective operation of the RF cavities in the superconducting accelerators demands fast, high-power RF vector modulators. Recent progress in development of the new materials, ferroelectrics, having tunable dielectric constant and acceptable losses [*] gives the possibility development of such devises. In previous papers [**-***] the authors described different L-band ferroelectric phase shifter designs . At low RF level high operation speed of 2 degree/nsec was demonstrated in waveguide phase shifter. However, the experiments show that a special technology is to be developed that provides a good electric contact between ceramics and the metallic wall. In present paper a new design of the fast high–power ferroelectric phase shifter is described based on the simple ferroelectric elements.
* A. Kanareykin, et al, IPAC 2010, p. 3987
** S. Kazakov, et al, “Fast Ferroelectric Phase Shifter Design For ERLs,” 45th ICFA Beam Dynamics Workshop, 2009
*** S. Kazakov, et al, PAC2007, p. 599.
 
 
TUP074 Experiments on HOM Spectrum Manipulation in a 1.3 GHz ILC SC Cavity 958
 
  • T.N. Khabiboulline, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Superconducting cavities with high operating Q will be installed in the Project-X, a superconducting linac, which is under development at Fermilab. Possibility of cavity design without HOM couplers considered. Rich spectrum of the beam and large number of cavities in ProjectX linac can result to resonance excitation of some high order modes with high shunt impedance. Under scope of study of High Order Modes (HOM) damping the manipulation with HOM spectrum in cold linac is considered. Results of detuning HOM spectrum of 1.3 GHz cavities at 2K in Horizontal Test Station of Fermilab are presented. Possible explanation of the phenomena is discussed.  
 
TUP075 Cavity Loss Factors of Non-relativistic Beams for Project X 961
 
  • A. Lunin, S. Kazakov, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Cavity loss factor calculation is an important part of total cryolosses estimation for the super conductive (SC) accelerating structures. There are two approaches how to calculate cavity loss factors, the integration of a wake potential over the bunch profile and the combining of loss factors for individual cavity modes. We applied both methods in order to get reliable results for non-relativistic beam. The time domain CST solver was used for a wake potential calculation and the frequency domain HFSS code was used for the cavity eigenmodes spectrum findings. Finally we present the results of cavity loss factors simulations for a non-relativistic part of the ProjectX and analyze it for various beam parameters.  
 
TUP076 First High Power Pulsed Tests of a Dressed 325 MHz Superconducting Single Spoke Resonator at Fermilab 964
 
  • R.L. Madrak, J. Branlard, B. Chase, C. Darve, P.W. Joireman, T.N. Khabiboulline, A. Mukherjee, T.H. Nicol, E. Peoples-Evans, D.W. Peterson, Y.M. Pischalnikov, L. Ristori, W. Schappert, D.A. Sergatskov, W.M. Soyars, J. Steimel, I. Terechkine, V. Tupikov, R.L. Wagner, R.C. Webber, D. Wildman
    Fermilab, Batavia, USA
 
  In the recently commissioned superconducting RF cavity test facility at Fermilab (SCTF), a 325 MHz, β=0.22 superconducting single-spoke resonator (SSR1) has been tested for the first time with its input power coupler. Previously, this cavity had been tested CW with a low power, high Qext test coupler; first as a bare cavity in the Fermilab Vertical Test Stand and then fully dressed in the SCTF. For the tests described here, the design input coupler with Qext ~ 106 was used. Pulsed power was provided by a Toshiba E3740A 2.5 MW klystron.  
 
TUP077 Vibrational Measurements for Commissioning SRF Accelerator Test Facility at Fermilab 967
 
  • M.W. McGee, J.R. Leibfritz, A. Martinez, Y.M. Pischalnikov, W. Schappert
    Fermilab, Batavia, USA
 
  Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02- 07CH11359 with the U.S. Department of Energy.
The commissioning of two cryomodule components is underway at Fermilab’s Superconducting Radio Frequency (SRF) Accelerator Test Facility. The research at this facility supports the next generation high intensity linear accelerators such as the International Linear Collider (ILC), a new high intensity injector (Project X) and other future machines. These components, Cryomodule #1 (CM1) and Capture Cavity II (CC2) which contain 1.3 GHz cavities are connected in series in the beamline and through cryogenic plumbing. Studies regarding characterization of ground motion, technical and cultural noise continue. Mechanical transfer functions between the foundation and critical beamline components have been measured and overall system displacement characterized. Baseline motion measurements given initial operation of cryogenic, vacuum systems and other utilities are considered.

 
 
TUP079 Cryomodule Design for 325 MHz Superconducting Single Spoke Cavities and Solenoids 970
 
  • T.H. Nicol, S. Cheban, R.L. Madrak, F. McConologue, T.J. Peterson, V. Poloubotko, L. Ristori, W. Schappert, I. Terechkine, B.A. Vosmek
    Fermilab, Batavia, USA
 
  Funding: U.S. Department of Energy
The low-beta section of the linac being considered for Project X at Fermilab contains several styles of 325 MHz superconducting single spoke cavities and solenoid based focusing lenses, all operating at 2 K. Each type of cavity and focusing lens will eventually be incorporated into the design of cryomodules unique to various sections of the linac front end. This paper describes the design of a multiple-cavity and solenoid cryomodule being developed to test the function of each of the main cryomodule systems – cryogenic systems and instrumentation, cavity and lens positioning and alignment, conduction-cooled current leads, magnetic shielding, cold-to-warm beam tube transitions, interfaces to interconnecting equipment and adjacent modules, as well as evaluation of overall assembly procedures.
 
 
TUP080 Tests of a Tuner for a 325 MHz SRF Spoke Resonator 973
 
  • Y.M. Pischalnikov, E. Borissov, T.N. Khabiboulline, R.L. Madrak, R.V. Pilipenko, L. Ristori, W. Schappert
    Fermilab, Batavia, USA
 
  Funding: Work is supported by the U.S. Department of Energy
Fermilab is developing 325 MHz SRF spoke cavities for the proposed ProjectX. A compact fast/slow tuner has been developed to compensate microphonics and Lorentz force detuning. The modified tuner design and results of 4K tests of the first prototype are presented.
 
 
TUP082 Test of a Coaxial Blade Tuner at HTS/FNAL 976
 
  • Y.M. Pischalnikov, S. Barbanotti, E.R. Harms, A. Hocker, T.N. Khabiboulline, W. Schappert
    Fermilab, Batavia, USA
  • A. Bosotti, C. Pagani, R. Paparella
    INFN/LASA, Segrate (MI), Italy
 
  Funding: Work is supported by the U.S. Department of Energy
Fermilab is building Cryomodule 2 for ILCTA facility at NML. A coaxial blade tuner has been chosen for the CM2 1.3GHz SRF cavities. A summary of results from cold test of the tuners in the Fermilab Horizontal Test Stand will be presented.
 
 
TUP083 Phase and Frequency Locked Magnetrons for SRF Sources 979
 
  • M. Popovic, A. Moretti
    Fermilab, Batavia, USA
  • M.A.C. Cummings, A. Dudas, R.P. Johnson, M.L. Neubauer, R. Sah
    Muons, Inc, Batavia, USA
 
  Funding: Supported in part by STTR Grant DE-SC0002766
In order to make use of ferrite and/or garnet materials in the phase and frequency locked magnetron, for which Muons, Inc., received a Phase II award, materials must be tested in two orthogonal magnetic fields. One field is from the biasing field of the magnetron, the other from the biasing field used to control the ferrite within the anode structure of the magnetron. A test fixture was built and materials are being tested to determine their suitability. The status of those material tests are reported on in this paper.
 
 
TUP084 Design of Single Spoke Resonators for Project X 982
 
  • L. Ristori, S. Barbanotti, M.S. Champion, M.H. Foley, I.G. Gonin, C.J. Grimm, T.N. Khabiboulline, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Project X is based on a 3 GeV CW superconducting linac and is currently in the R&D phase awaiting CD-0 approval. The low-energy section of the Project X H-linac includes three types of super-conducting single spoke cavities operating at 325 MHz. SSR0 (26 cavities), SSR1 (18 cavities) and SSR2 (44 cavities) have a geometrical beta of = 0.11, 0.21 and 0.4 respectively. Single spoke cavities were selected for the linac in virtue of their higher r/Q. In this paper we present the decisions and analyses that lead to the final designs. Electro-magnetic and mechanical finite element analyses were performed with the purpose of optimizing the electro-magnetic design, minimizing frequency shifts due to Helium bath pressure fluctuations and providing a pressure rating for the resonators that allow their use in the cryomodules.  
 
TUP085 Assumptions for the RF Losses in the 650 MHz Cavities of the Project X Linac 985
 
  • A. Romanenko, L.D. Cooley, J.P. Ozelis, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  The requirements for the FNAL Project X cryogenic system depend on the dynamic heat loads of 650 MHz cavities. The heat load is in turn determined by quality factors of the cavities at the operating gradient. In this contribution we use the available experimental data to analyze quality factors achievable in 650 MHz linac cavities taking into account different RF losses contributions such as BCS resistance, residual resistance and a medium field Q-slope.  
 
TUP086 Microphonics control for Project X 988
 
  • W. Schappert, S. Barbanotti, J. Branlard, G.I. Cancelo, R.H. Carcagno, M.S. Champion, B. Chase, I.G. Gonin, A.L. Klebaner, D.F. Orris, T.J. Peterson, Y.M. Pischalnikov, L. Ristori, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Funding: Work is supported by the U.S. Department of Energy
The proposed multi-MW Project X facility at Fermilab will employ cavities with bandwidths as narrow as 20 Hz. This combination of high RF power with narrow bandwidths combined requires careful attention to detuning control if these cavities are to be operated successfully. Detuning control for Projects X will require a coordinated effort between the groups responsible for various machine subsystems. Considerable progress in this area has been made over the past year.
 
 
TUP088 Resonance Effects of Longitudinal HOMs in Project X Linac 991
 
  • V.P. Yakovlev, I.G. Gonin, T.N. Khabiboulline, A. Lunin, N. Solyak, A.I. Sukhanov, A. Vostrikov
    Fermilab, Batavia, USA
  • A. Saini
    University of Delhi, Delhi, India
 
  High-order mode influence on the beam longitudinal and transverse dynamics is considered for the 650 MHz section of the Project X linac. RF losses caused by HOMs are analyzed. Necessity of HOM dampers in the SC cavities of the linac is discussed.  
 
TUP089 Concept EM Design of the 650 MHz Cavities for the Project X 994
 
  • V.P. Yakovlev, M.S. Champion, I.G. Gonin, T.N. Khabiboulline, A. Lunin, N. Solyak
    Fermilab, Batavia, USA
  • A. Saini
    University of Delhi, Delhi, India
 
  Concept of the 650 MHz cavities for the Project X is presented. Choice of the basic parameters, i.e, number of cells, geometrical β, apertures, coupling coefficients, etc, is discussed. The cavities optimization criteria are formulated. Results of the RF design are presented for the cavities of both low-energy and high energy sections.  
 
TUP090 Design of a β = 0.29 Half-wave Resonator for the FRIB Driver Linac 997
 
  • J.P. Holzbauer, W. Hartung, J. Popielarski
    NSCL, East Lansing, Michigan, USA
 
  The driver linac for the Facility for Rare Isotope Beams will produce primary beams of ions at 200 MeV per nucleon for nuclear physics research. The driver linac will require 344 superconducting cavities, consisting of two types of Quarter-Wave Resonators (QWRs, β = 0.041 and 0.085) and two types of Half-Wave Resonators (HWRs, β = 0.29 and 0.53). A first-generation β = 0.29 HWR has been designed, prototyped, and tested. Second-generation versions of the other cavities are being developed, with one or more prototype having been tested. A second-generation β = 0.29 HWR design has been developed, making use of the experience with the first-generation β = 0.29 HWR and second-generation β = 0.53 HWR. In the second-generation design, the inner conductor is tapered to reduce the peak surface magnetic field. The outer conductor is a straight tube to increase the mechanical stiffness and reduce the sensitivity of the resonant frequency to bath pressure fluctuations. Optimization was employed to minimize the peak surface electric field. The second-generation β = 0.29 HWR design will be presented, including the RF design and mechanical analysis.  
 
TUP091 Electromagnetic Design of a Multi-harmonic Buncher for the FRIB Driver Linac 1000
 
  • J.P. Holzbauer, W. Hartung, F. Marti, Q. Zhao
    NSCL, East Lansing, Michigan, USA
  • E. Pozdeyev
    FRIB, East Lansing, Michigan, USA
 
  Funding: Work supported by the U.S. Department of Energy under Grant Number DE-FGO2-08ER41553.
The driver linac for the Facility for Rare Isotope Beams (FRIB) at MSU will produce primary beams of ions at ≥200 MeV/u for nuclear physics research. A dc ion beam from an ECR ion source will be pre-bunched upstream of the radio frequency quadrupole linac. A multi-harmonic buncher (MHB) was designed for this purpose, using experience gained with a similar buncher for the ReA3 re-accelerator linac, which is presently being commissioned at MSU. The FRIB MHB resonator operates with three frequencies (40.25 MHz, 80.5 MHz, and 120.75 MHz) to produce an approximately linear sawtooth in the voltage as a function of time. The three resonant frequencies are produced via two quarter-wave resonators with a common gridless gap: one resonator is driven at its fundamental mode at 40.25 MHz and its first higher-order mode (120.75 MHz), while the other is driven only at its fundamental mode of 80.5 MHz. The electromagnetic design of the MHB resonator will be presented, including the electrode design and tuning mechanisms.
 
 
TUP092 Multi-purpose 805 MHz Pillbox RF Cavity for Muon Acceleration Studies 1003
 
  • G.M. Kazakevich, G. Flanagan, R.P. Johnson, M.L. Neubauer, R. Sah
    Muons, Inc, Batavia, USA
  • K.C.D. Chan, A.J. Jason, S.S. Kurennoy, H.M. Miyadera, P.J. Turchi
    LANL, Los Alamos, New Mexico, USA
  • A. Moretti, M. Popovic, K. Yonehara
    Fermilab, Batavia, USA
  • Y. Torun
    IIT, Chicago, Illinois, USA
 
  Funding: Supported by DOE grant DE-FG-08ER86352.
An 805 MHz RF pillbox cavity has been designed and constructed to investigate potential muon beam acceleration and cooling techniques. The cavity can operate in vacuum or under pressure to 100 atmospheres, at room temperature or in an LN2 bath at 77 K. The cavity is designed for easy assembly and disassembly with bolted construction using aluminum seals. The surfaces of the end walls of the cavity can be replaced with different materials such as copper, aluminum, beryllium, or molybdenum, and with different geometries such as shaped windows or grid structures. Different surface treatments such as electro polished, high-pressure water cleaned, and atomic layer deposition are being considered for testing. The cavity has been designed to fit inside the 5-Tesla solenoid in the MuCool Test Area at Fermilab. Performance of the cavity, including initial conditioning and operation in the external magnetic field will be reported.
 
 
TUP094 Novel Crab Cavity RF Design 1006
 
  • M.L. Neubauer, A. Dudas, R. Sah
    Muons, Inc, Batavia, USA
  • R.A. Rimmer, H. Wang
    JLAB, Newport News, Virginia, USA
 
  Funding: Supported in part by DOE SBIR grant DE-SC0005444
A 20-50 MV integrated transverse voltage is required for the Electron-Ion Collider. The most promising of the crab cavity designs that have been proposed in the last five years are the TEM type crab cavities because of the higher transverse impedance. The TEM design approach is extended here to a hybrid crab cavity that includes the input power coupler as an integral part of the design. A prototype was built with Phase I monies and tested at JLAB. The results reported on, and a system for achieving 20-50 MV is proposed.
 
 
TUP095 Adjustable High Power Coax Coupler without Moving Parts 1009
 
  • M.L. Neubauer, A. Dudas, R. Sah
    Muons, Inc, Batavia, USA
  • R. Nassiri
    ANL, Argonne, USA
 
  An RF power coupler is designed to operate without moving parts. This new concept for an adjustable coupler is applicable to operation at any radiofrequency. CW operation of such a coupler is especially challenging at lower frequencies. The basic component of the coupler is a ferrite tuner. The RF coupler has no movable parts and relies on a ferrite tuner assembly, coax TEE, and double windows to provide a VSWR of better than 1.05:1 and a bandwidth of at least 8 MHz at 1.15:1. The ferrite tuner assembly on the stub end of the coax TEE uses an applied DC magnetic field to change the Qext and the RF coupling coefficient between the RF input and the cavity. Recent work in making measurements of the loss in the ferrite and likely thermal dissipation required for 100 kW CW operation is presented.  
 
TUP096 Beam Pipe HOM Absorber for SRF Cavities 1012
 
  • R. Sah, A. Dudas, M.L. Neubauer
    Muons, Inc, Batavia, USA
  • G.H. Hoffstaetter, M. Liepe, H. Padamsee, V.D. Shemelin
    CLASSE, Ithaca, New York, USA
  • K. Ko, C.-K. Ng, L. Xiao
    SLAC, Menlo Park, California, USA
 
  Funding: Supported in part by DOE SBIR grant DE-SC0002733 and USDOE Contract No. DE-AC05-84-ER-40150.
Superconducting RF (SRF) systems typically contain resonances at unwanted frequencies, or higher order modes (HOM). For storage ring and linac applications, these higher modes must be damped by absorbing them in ferrite and other lossy ceramic materials. Typically, these absorbers are brazed to substrates that are often located in the drift tubes adjacent to the SRF cavity. These HOM absorbers must have broadband microwave loss characteristics and must be thermally and mechanically robust, but the ferrites and their attachments are weak under tensile and thermal stresses and tend to crack. Based on prior work on HOM loads for high current storage rings and for an ERL injector cryomodule, a HOM absorber with improved materials and design is being developed for high-gradient SRF systems. This work will use novel construction techniques (without brazing) to maintain the ferrite in mechanical compression. Attachment techniques to the metal substrates will include process techniques for fully-compressed ferrite rings. Prototype structures will be fabricated and tested for mechanical strength under thermal cycling conditions.
 
 
TUP097 Fundamental and HOM Coupler Design for the Superconducting Parallel-Bar Cavity 1015
 
  • S.U. De Silva, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • S.U. De Silva
    JLAB, Newport News, Virginia, USA
 
  The superconducting parallel-bar cavity is currently being considered as a deflecting system for the Jefferson Lab 12 GeV upgrade and as a crabbing cavity for a possible LHC luminosity upgrade. Currently the designs are optimized to achieve lower surface fields within the dimensional constraints for the above applications. A detailed analysis of the fundamental input power coupler design for the parallel-bar cavity is performed considering beam loading and the effects of microphonics. For higher beam loading the damping of the HOMs is vital to reduce beam instabilities generated due to the wake fields. An analysis of threshold impedances for each application and impedances of the modes that requires damping are presented in this paper with the design of HOM couplers.  
 
TUP098 Multipacting Analysis of the Superconducting Parallel-bar Cavity 1018
 
  • S.U. De Silva, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • S.U. De Silva
    JLAB, Newport News, Virginia, USA
 
  The superconducting parallel-bar cavity is a deflecting/crabbing cavity with attractive properties, compared to other conventional designs, that is being considered for a number of applications. Multipacting can be a limiting factor to the performance of in any superconducting structure. In the parallel-bar cavity the main contribution to the deflection is due to the transverse deflecting voltage, between the parallel bars, making the design potentially prone to multipacting. This paper presents the results of analytical calculations and numerical simulations of multipacting in the parallel-bar cavity with resonant voltage, impact energies and corresponding particle trajectories.  
 
TUP099 Design of Superconducting Parallel-bar Deflecting/Crabbing Cavities with Improved Properties 1021
 
  • J.R. Delayen, S.U. De Silva
    ODU, Norfolk, Virginia, USA
  • J.R. Delayen
    JLAB, Newport News, Virginia, USA
 
  The superconducting parallel-bar cavity is a deflecting/crabbing cavity with attractive properties, compared to other conventional designs, that is being considered for a number of applications. All designs to-date have been based on straight loading elements and rectangular outer conductors. We present new designs of parallel-bar cavities using curved loading elements and circular or elliptical outer conductors, with significantly improved properties such as reduced surface fields and wider higher-order mode separation.  
 
TUP100 Design of Superconducting Spoke Cavities for High-velocity Applications 1024
 
  • J.R. Delayen, S.U. De Silva, C.S. Hopper
    ODU, Norfolk, Virginia, USA
  • J.R. Delayen
    JLAB, Newport News, Virginia, USA
 
  Superconducting single- and multi-spoke cavities have been designed to-date for particle velocities from β~0.15 to β~0.65. Superconducting spoke cavities may also be of interest for higher-velocity, low-frequency applications, either for hadrons or electrons. We present the design of spoke cavities optimized for β=0.8 and β=1.  
 
TUP101 Plasma Treatment of Single-Cell Niobium SRF Cavities 1027
 
  • J. Upadhyay, M. Nikolić, S. Popović, L. Vušković
    ODU, Norfolk, Virginia, USA
  • H.L. Phillips, A-M. Valente-Feliciano
    JLAB, Newport News, Virginia, USA
 
  In our previous work, we have demonstrated on flat sam- ples that plasma etching in Ar/Cl2 of bulk Nb is a viable alternative surface preparation technique to BCP and EP methods, with comparable etching rates. Here we report on the progress in experimental design for plasma processing of a single cell SRF cavity. The experiments are centered on two discharge types - asymmetric RF and low mode mi- crowave cavity discharge. We report on the experimental design of the setup with a specially designed single cell cavity with sample holders, and discuss the diagnostics of plasma and samples. We provide preliminary results on the RF discharge in the single cell that is to be the main part of the optimized experiment.  
 
TUP102 Cryogenic RF Material Testing at SLAC 1030
 
  • J. Guo, D.W. Martin, S.G. Tantawi, C. Yoneda
    SLAC, Menlo Park, California, USA
 
  Funding: The work is supported by the US Department of Energy
We have been developing an X-band cryogenic RF material testing system since 2005. By measuring the Q of a hemispherical cavity with the material sample at is flat interchangeable bottom, the system is capable to characterize the surface resistance of different materials at the temperature of 3-300K, as well as the quenching RF magnetic field of the superconducting samples at different temperatures. Using a SLAC X-band 50 MW klystron, the system can measure the quenching H-field of up to 300mT under current setup, with the possibility of further enhancement by changing the RF distribution configuration.
 
 
TUP104 Nb3Sn Block-coil Dipole for High-field Substitution in the LHC Lattice 1033
 
  • A. Sattarov, E.F. Holik, A.D. McInturff, P.M. McIntyre
    Texas A&M University, College Station, Texas, USA
 
  Funding: This work was supported in part by the U.S. Department of Energy under Grant DE-FG02-06ER41405
A design is being developed to prototype for a dipole for this purpose: a block-coil dipole with 13 T short- sample field, 11 T working field, and 6 cm aperture. The dipole is a natural application of the high-field dipole strategy developed at Texas A&M, using simple pancake windings, flux-plate suppression of low-field multipoles, and bladder preloading. A short model dipole is planned.
 
 
TUP105 Fabrication of a Model Polyhedral Superconducting Cavity 1035
 
  • N. Pogue, P.M. McIntyre, A. Sattarov
    Texas A&M University, College Station, Texas, USA
 
  Funding: This work was supported in part by the U.S. Department of Energy under Grant DE-FG02-06ER41405
The polyhedral cavity is a superconducting cavity structure in which a multi-cell cavity is built from a Roman-arch assembly of arc segments. Each segment has a Tesla-like r-z profile, and is fabricated either by bonding a Nb foil to a Cu substrate wedge or by depositing a Nb surface on the Cu substrate. The segments are assembled with an arrangement of locking rings and alignment pins, with a controlled narrow gap between segments over much of the arc-span of adjoining segments. A tubular channel is machined in the mating surfaces of the Cu wedges. Dipole modes are suppressed by locating along each channel a tube coated with rf-terminating ferrite. A first model of the cavity is being built to investigate mode structure, evaluate alternatives for the Nb surface fabrication, and develop assembly procedures.
 
 
TUP106 Effect of Surface Flow on Topography in Niobium Electropolishing 1038
 
  • M.J. Kelley, C.E. Reece
    JLAB, Newport News, Virginia, USA
  • L. Zhao
    The College of William and Mary, Williamsburg, USA
 
  Funding: This work has been supported by U.S. DOE Contract No. DE-AC05-06OR23177 to Jefferson Lab
Electropolishing (EP) is reliably delivering improved performance of multi-celled niobium SRF accelerator cavities, attributed to the smoother surface obtained. This superior leveling is a consequence of an etchant concentration gradient layer that arises in the HF-H2SO4 electrolyte adjacent to the niobium surface during polishing. Electrolyte circulation raises the prospect that fluid flow adjacent to the surface might affect the diffusion layer and impair EP performance. In this study, preliminary bench-top experiments with a moving electrode apparatus were conducted. We find that flow conditions approximating cavity EP show no effects attributable to depletion layer disruption.
 
 
TUP107 RF-thermal Combined Simulations of a Superconducting HOM Coaxial Coupler 1041
 
  • G. Cheng, H. Wang
    JLAB, Newport News, Virginia, USA
  • D.N. Smithe
    Tech-X, Boulder, Colorado, USA
 
  Funding: This work is supported by Jefferson LAB and Tech-X CRADA #2009S005 on “Simulations of Electromagnetic and Thermal Characteristics of SRF Structures”.
To benchmark a multi-physics code VORPAL developed by Tech-X, the High Order Mode (HOM) coaxial coupler design implemented in Jefferson Lab’s 12GeV upgrade cryomodules is analyzed by use of commercial codes, such as ANSYS, HFSS and Microwave Studio. Testing data from a Horizontal Test Bed (HTB) experiment on a dual-cavity prototype are also utilized in the verification of simulation results. The work includes two stages: first, the HOM feedthrough that has a high RRR niobium probe and sapphire insulator is analyzed for the RF-thermal response when there is traveling wave passing through; second, the HTB testing condition is simulated and results from simulation are compared to thermal measurements from HTB tests. The analyses are of coupled-field nature and involve highly nonlinear temperature dependent thermal conductivities and electric resistivities for the eight types of materials used in the design. Accuracy and efficiency are the main factors in evaluation of the performance of the codes.
 
 
TUP108 Summary Report for the C50 Cryomodule Project 1044
 
  • M.A. Drury, G.K. Davis, J.F. Fischer, C. Grenoble, J. Hogan, L.K. King, K. Macha, J.D. Mammosser, C.E. Reece, A.V. Reilly, J. Saunders, H. Wang
    JLAB, Newport News, Virginia, USA
  • E. Daly, J.P. Preble
    ITER Organization, St. Paul lez Durance, France
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract DE-AC05-06OR23177.
The Thomas Jefferson National Accelerator Facility has recently completed the C50 cryomodule refurbishment project. The goal of this project was to enable robust 6 GeV, 5 pass operation of the Continuous Electron Beam Accelerator Facility (CEBAF). The scope of the project included removal, refurbishment and reinstallation of ten CEBAF cryomodules at a rate of three per year. The refurbishment process included reprocessing of SRF cavities to eliminate field emission and to increase the nominal gradient from the original 5 MV/m to 12.5 MV/m. New “dogleg“ couplers were installed between the cavity and helium vessel flanges to intercept secondary electrons that produce arcing in the fundamental Power Coupler (FPC). Other changes included new ceramic RF windows for the air to vacuum interface of the FPC and improvements to the mechanical tuner. Damaged or worn components were replaced as well. All ten of the refurbished cryomodules are now installed in CEBAF and are currently operational. This paper will summarize the performance of the cryomodules. This paper will also look at problems that must be addressed by future refurbishment projects.
The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.
 
 
TUP109 Fabrication, Treatment and Testing of a 1.6 Cell Photo-injector Cavity for HZB 1047
 
  • P. Kneisel
    JLAB, Newport News, Virginia, USA
  • T. Kamps, J. Knobloch, O. Kugeler, A. Neumann
    HZB, Berlin, Germany
  • R. Nietubyc
    The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock, Poland
  • J.K. Sekutowicz
    DESY, Hamburg, Germany
 
  Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177..
As part of a CRADA (Cooperative Research and Development Agreement) between Forschungszentrum Dresden (FZD) and JLab we have fabricated and tested after appropriate surface treatment a 1.5 cell, 1300 MHz RRR niobium photo-injector cavity to be used in a demonstration test at BESSY*. Following a baseline test at JLab, the cavity received a lead spot coating of ~8 mm diameter deposited with a cathode arc at the Soltan Institute on the endplate made from large grain niobium. It had been demonstrated in earlier tests with a DESY built 1.5 cell cavity – the original design – that a lead spot of this size can be a good electron source, when irradiated with a laser light of 213 nm . In the initial test with the lead spot we could measure a peak surface electric field of ~ 29 MV/m; after a second surface treatment, carried out to improve the cavity performance, but which was not done with sufficient precaution, the lead spot was destroyed and the cavity had to be coated a second time. This contribution reports about the experiences and results obtained with this cavity.
* A. Neumann et al., “CW Superconducting RF Photoinjector Development for Energy Recovery Linacs”, LINAC10, September 13-17, 2010, Tsukuba, Japan.
 
 
TUP111 Multipactoring Observation, Simulation and Suppression on a Superconducting TE011 Cavity 1050
 
  • H. Wang, G. Ciovati
    JLAB, Newport News, Virginia, USA
  • L. Ge, Z. Li
    SLAC, Menlo Park, California, USA
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and COMPASS of SciDAC No.
A superconducting cavity of the same shape as used for the development of superconducting photo injectors has been built for the studies of high magnetic field induced Q slope due to the local heating. The multipactoring problem has been observed on the TE011 mode, 3.3GHz with magnetic field barriers. To understand and overcome this problem, 3D multipactoring simulations by Omega3P and Track3P have been done and found these to be one-point multipactors pulled out from the flat bottom surface by finite normal component of electric field. Asymmetric coupling ports on the side of the beam tube could have caused the distortion of the TE011 mode. The thermometry measurement later confirmed the predicted impact locations. A structure modification has been adopted based on the simulation prediction. More experimental results with the new geometry will allow further comparison with the 3D multipactoring simulations.
 
 
TUP114 Rugged Solid-state RF Amplifiers for Accelerator Applications - Design and Performance from an Industry Perspective 1053
 
  • S.C. Dillon, B.S. Nobel, J.L. Reid, C.P. Schach, W.J. Villena Gonzales
    Tomco Technologies, Stepney, South Australia, Australia
 
  Recent advances in transistor technology are making solid-state RF amplifiers an increasingly viable alternative to tube systems in accelerator applications. This paper details the development and performance of a range of new high power amplifiers, based on current MOSFET technology, and designed specifically for this application. A generic modular architecture that can be used to construct high power CW amplifier systems operating from HF up to S-band, is detailed. Key design considerations in terms of modularity, redundancy, reliability and cost are discussed.  
 
TUP117 Solid State Direct Drive RF LINAC: High Power Experimental Program 1056
 
  • T.J.S. Hughes, M. Back, R. Fleck, M. Hergt, R. Irsigler, T. Kluge, J. Sirtl
    Siemens AG, Erlangen, Germany
  • O. Heid
    Siemens AG, Healthcare Technology and Concepts, Erlangen, Germany
 
  We report on a 150MHz λ/4 coaxial resonator driven by 32 integrated class F RF power modules according to our direct drive concept [1,2]. Electric fields of 60MV/m at the resonator gap have been reached, which correspond to 80kW RF power. This power level has been achieved at 160V DC supply voltage, significantly less than the component limits. The observed power and Q values can be explained by a simple equivalent circuit. The model predicts that 64 modules at 160V DC supply voltage may provide 170kW RF power, and that 250V DC supply voltage should yield 400kW. The corresponding 134MV/m gap E field may not be reachable due to vacuum flashover.
* Heid O., Hughes T. THPD002, IPAC10, Kyoto, Japan
** Hergt M et al, 2010 IEEE International Power Modulator and High Voltage Conf., Atlanta GA, USA
*** Heid O., Hughes T. THP068, LINAC10, Tsukuba, Japan
 
 
TUP123 Performance of the 352-MHz 4-kW CW Solid State RF Power Amplifier System using 1-kW Push-pull Devices 1059
 
  • D. Horan, G.J. Waldschmidt
    ANL, Argonne, USA
 
  Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
Development and testing of a prototype 352-MHz, 4-kW cw solid state rf power amplifier system is underway at the Advanced Photon Source to study and evaluate the performance advantages of an upgrade to solid state rf power technology at the APS. General performance measurement data on the assembled amplifier system is discussed, with emphasis on efficiency improvements possible through the use of dynamic drain voltage control.
 
 
TUP124 Phase Contrast Imaging Using a Single Picosecond X-ray Pulse of the Inverse Compton Source at the BNL Accelerator Test Facility 1062
 
  • M. Carpinelli
    Università di Sassari and INFN, Sassari, Italy
  • P. Delogu, M. Endrizzi
    INFN-Pisa, Pisa, Italy
  • B. Golosio, P. Oliva
    INFN-Cagliari, Monserrato (Cagliari), Italy
  • I. Pogorelsky, V. Yakimenko
    BNL, Upton, Long Island, New York, USA
 
  Inverse Compton scattering (ICS) X-ray sources are of current interest due to their novel features that enable new methods in medical and biological imaging. As a compelling example of such a possibility, we present an experimental demonstration of single shot inline phase contrast imaging using the ICS source located at the BNL Accelerator Test Facility. The phase contrast effect is clearly observed in the images obtained. Further, its qualities are shown to be in agreement with the predictions of theoretical models through comparison of experimental and simulated images of a set of plastic wires of differing composition and size. We also display an example of application of the technique to single shot phase contrast imaging of a biological sample.  
 
TUP125 High Power RF Systems for the BNL ERL Project 1065
 
  • A. Zaltsman, R.F. Lambiase
    BNL, Upton, Long Island, New York, USA
 
  The Energy Recovery Linac (ERL) project, now under construction at Brookhaven National Laboratory, requires two high power RF systems. The first RF system is for the 703.75 MHz superconducting electron gun. The RF power from this system is used to drive nearly half an Ampere of beam current to 2.5 MeV. There is no provision to recover any of this energy so the minimum amplifier power is 1 MW. It consists of 1 MW CW klystron, transmitter and power supplies, 1 MW circulator, 1 MW dummy load and a two-way power splitter. The second RF system is for the 703.75 MHz superconducting cavity. The system accelerates the beam to 54.7 MeV and recovers this energy. It will provide up to 50 kW of CW RF power to the cavity. It consists of 50 kW transmitter, circulator, and dummy load. This paper describes the two high power RF systems and presents the test data for both.  
 
TUP126 Development of a 10 kW CW, S-Band, PPM Focused Klystron 1068
 
  • P. Ferguson, R.L. Ives, D. Marsden, M.E. Read
    CCR, San Mateo, California, USA
 
  Funding: US Department of Energy SBIR Contract DE-SC0004558
Calabazas Creek Research Inc. (CCR) is developing a 100 kW CW, 2.815 GHz klystron for use in the Advanced Photon Source upgrade light source at Argonne National Laboratory. Periodic permanent magnet (PPM) focusing is used to avoid loss in efficiency due to the power normally required for a solenoid. The PPM structure elements consist of 4 disk (pill box) magnets with a clover-leaf shaped iron pole piece. The gaps between the magnets permit the introduction of liquid cooling into the RF circuit. Design tools include the large signal codes KLSC and TESLA for the efficiency calculations, MAXWELL 3D for the magnetic fields, and the CCR 3D code BOA for the beam trajectories. From initial simulations with seven cavities, the efficiency will be over 62% with a beam voltage of 47 kV. The saturated gain is 44 dB. The design emphasizes high reliability, with simple construction, robust cooling and low thermal loading through high efficiency. The paper will include the details of the design, including results of the simulations of the RF and magnetic structures, beam trajectories, and thermo-mechanical analyses.
 
 
TUP128 Development of a 402.5 MHz 140 kW Inductive Output Tube (IOT) 1070
 
  • M.E. Read, T. Bui, R.L. Ives, R.H. Jackson
    CCR, San Mateo, California, USA
  • I.A. Chernyavskiy, H. Freund
    SAIC, McLean, USA
 
  Funding: US Department of Energy under SBIR contract DE-SC0004566
Calabazas Creek Research Inc. (CCR) is developing a pulsed 140 kW, 402.5 MHz Inductive Output Tube (IOT) for use in proton accelerators. Unlike other high power multiple-beam IOT's currently under development, this device will use a single electron beam, and will be less expensive and have a higher reliability. The program includes the use of new design tools, including NEMESIS and a version of CCR's 3D Beam Optics Analysis (BOA) code modified to include time dependent modeling. The design will include the electron gun, collector, input and output cavities, input and output couplers and the RF output window. An emphasis will be placed on the electron gun, which will as usual include a grid for the high frequency modulation, and the input cavity. The new version of BOA is expected to be particularly useful in modeling the formation of the bunched beam and will replace the relatively slow 3D PIC code MAGIC as the primary design tool. HFSS and NEMESIS will be used for design of the input cavity. The paper will include details of the design.
 
 
TUP129 Simulation Results of RF Coupler Controllable by Dielectric Fluid 1073
 
  • P. Chen, D. Yu
    DULY Research Inc., Rancho Palos Verdes, California, USA
 
  Funding: Work supported by DOE SBIR Phase I grant No. DE-FG02-09ER85334.
Tunable couplers for adjusting radiofrequency (RF) power coupling into accelerator cavities are useful devices for achieving optimal operation efficiency. Standard mechanical tuners currently used in large accelerator facilities are bulky and complicated. A novel tuner, based on the introduction of dielectric tubes or fluid-filled volumes adjacent to, but separated by window(s) from the coupler, is described. Simulations have shown that the tuner has a fairly large adjustment range and also demonstrated the viability of the tuning concept using fluid circuit.
 
 
TUP130 Experiments on Voltage Droop Compensation for High Power Marx Modulators 1076
 
  • P. Chen, M. Lundquist, D. Yu
    DULY Research Inc., Rancho Palos Verdes, California, USA
 
  Funding: Work supported by DOE SBIR Phase II grant DE-FG02-08ER85052
Marx modulators, promising higher efficiency, longer lifetime and reduced cost compared with existing hard tube modulator options, are under intensive research. In this article, we describe the progress of work on our voltage droop compensation scheme for a Marx modulator. Experimental results on a compensation circuit at moderate voltage are presented.
 
 
TUP131 A New Main Injector Radio Frequency System For 2.3 MW Project X Operations 1079
 
  • J.E. Dey, I. Kourbanis
    Fermilab, Batavia, USA
 
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
For Project X Fermilab Main Injector will be required to provide up to 2.3 MW to a neutrino production target at energies between 60 and 120 GeV. To accomplish the above power levels 3 times the current beam intensity will need to be accelerated. In addition the injection energy of Main Injector will need to be as low as 6 GeV. The current 30 year old Main Injector radio frequency system will not be able to provide the required power and a new system will be required. The specifications of the new system will be described.
 
 
TUP132 50 MW X-Band RF System for a Photoinjector Test Station at LLNL 1082
 
  • T.L. Houck, S.G. Anderson, C.P.J. Barty, G.K. Beer, R.R. Cross, G.A. Deis, C.A. Ebbers, D.J. Gibson, F.V. Hartemann, R.A. Marsh
    LLNL, Livermore, California, USA
  • C. Adolphsen, A.E. Candel, T.S. Chu, E.N. Jongewaard, Z. Li, T.O. Raubenheimer, S.G. Tantawi, A.E. Vlieks, F. Wang, J.W. Wang, F. Zhou
    SLAC, Menlo Park, California, USA
 
  Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, and funded by DHS Domestic Nuclear Detection Office.
In support of x-band photoinjector development efforts at LLNL, a 50 MW test station is being constructed to investigate structure and photocathode optimization for future upgrades. A SLAC XL-4 klystron capable of generating 50 MW, 1.5 microsecond pulses will be the high power RF source for the system. The timing of the laser pulse on the photocathode with the applied RF field places very stringent requirements on phase jitter and drift. To achieve these requirements, the klystron will be powered by a state of the art, solid-state, high voltage modulator. The 50 MW of RF power will be divided between the photoinjector and a traveling wave accelerator section. A high power phase shifter is located between the photoinjector and accelerator section to adjust the phasing of the electron bunches with respect to the accelerating field. A variable attenuator is included on the input of the photoinjector. The distribution system including the various x-band components is being designed and constructed. In this paper, we will present the design, layout, and status of the RF system.
 
 
TUP133 Mechanical Design and Fabrication of a New RF Power Amplifier for LANSCE 1085
 
  • Z. Chen, M.J. Borden, N.K. Bultman, C.A. Chapman, J. Davis, J.L. Ferris, T.S. Gomez, J.T.M. Lyles, A.C. Naranjo
    LANL, Los Alamos, New Mexico, USA
  • D. Baca, R.E. Bratton, R.D. Summers
    Compa Industries, Inc., Los Alamos, New Mexico, USA
 
  Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396
A Full-scale prototype of a new 201 MHz RF Final Power Amplifier (FPA) for Los Alamos Neutron Science Center (LANSCE) has been designed, fabricated, assembled and installed in the test facility. This prototype was successfully tested and met the physics and electronics design criteria. With a goal to produce 3.2 MW peak power at 15% duty factor, at the elevation of over 2 km in Los Alamos, The team faced design and manufacturing challenges. The mechanical design of the final power amplifier was built around a Thales TH628 Diacrode®, a state-of-art tetrode power tube*. The main structure includes Input circuit, Output circuit, Grid decoupling circuit, Output coupler, Tuning pistons, and a cooling system. Many kinds of material were utilized to make this new RF amplifier. The FPA is nearly 1000 kg and installed in a beam structural support stand. In this paper, we summarize the FPA design basis and fabrication, plating, and assembly process steps with necessary lifting and handling fixtures. In addition, to ensure the quality of the FPA support structure a finite element analysis with seismic design forces has also been carried out.
* J. Lyles, S. Archuletta, N. Bultman, Z. Chen, et al., “Design of a New VHF RF Power Amplifier System for LANSCE”, IPAC’10, Kyoto, Japan, May 24-28, 2010.
 
 
TUP134 New High Power Test Facility for VHF Power Amplifiers at LANSCE 1088
 
  • J.T.M. Lyles, S. Archuletta, J. Davis, L. Lopez, D. Rees, M.R. Rodriguez, G. M. Sandoval, Jr., A. Steck, D.J. Vigil
    LANL, Los Alamos, New Mexico, USA
  • D. Baca, R.E. Bratton, R.D. Summers
    Compa Industries, Inc., Los Alamos, New Mexico, USA
  • N.W. Brennan
    Texas A&M University, College Station, Texas, USA
 
  Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396
A new test facility was designed and constructed at Los Alamos Neutron Science Center (LANSCE) for testing the Thales TH628 Diacrode® and TH781 tetrode power amplifiers. Anode power requirements for the TH628 are 28 kV DC, with peak currents of 190 Amperes in long pulses. A new 225 uF capacitor bank supplies this demand. A charging power supply was obtained by re-configuring a 2 MW beam power supply remaining from another project. A traditional ignitron crowbar was designed to rapidly discharge the 88 kJ stored energy. The anode power supply was extensively tested using a pulsed tetrode switch and resistor load. A new Fast Protect and Monitor System (FPMS) was designed to take samples of RF reflected power, anode HV, and various tube currents, with outputs to quench the HV charging supply, remove RF drive and disable the conduction bias pulse to the grid of each tube during fault events. The entire test stand is controlled with a programmable logic controller, for normal startup sequencing and timing, protection against loss of cooling, and operator GUI.
 
 
TUP135 RF Design and Operating Results for a New 201.25 MHz RF Power Amplifier for LANSCE 1091
 
  • J.T.M. Lyles, N.K. Bultman, Z. Chen, J. Davis, A.C. Naranjo, D. Rees, G. M. Sandoval, Jr.
    LANL, Los Alamos, New Mexico, USA
  • D. Baca, R.E. Bratton, R.D. Summers
    Compa Industries, Inc., Los Alamos, New Mexico, USA
  • N.W. Brennan
    Texas A&M University, College Station, Texas, USA
 
  Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396
A prototype VHF RF Final Power Amplifier (FPA) for Los Alamos Neutron Science Center (LANSCE) has been designed, fabricated, and tested. The cavity amplifier met the design goals producing 3.2 MW peak and 480 kW of average power, at an elevation of 2.1 km. It was designed to use a Thales TH628 Diacrode®, a state-of-art tetrode power tube that is double-ended, providing roughly twice the power of a conventional tetrode. The amplifier is designed with tunable input and output transmission line cavity circuits, a grid decoupling circuit, an adjustable output coupler, TE mode suppressors, blocking, bypassing and decoupling capacitors, and a cooling system. The tube is connected in a full wavelength output circuit, with the lower main tuner situated ¾λ from the central electron beam region in the tube and the upper slave tuner ¼λ from the same point. We summarize the design processes and features of the FPA along with significant test results. A pair of production amplifiers are planned to be power-combined and installed at the LANSCE DTL to return operation to full beam duty factor.
 
 
TUP139 Initial High Power Test Results of an X-band Dual-moded Coaxial Cavity 1094
 
  • F. Wang, C. Adolphsen, C.D. Nantista
    SLAC, Menlo Park, California, USA
 
  To understand the rf breakdown phenomenon better, an x-band coaxial dual-moded cavity is designed. It is independently excited two modes from two sources. One mode will generator pulsed heating in the inner conductor and the other one will concentrate peak electric field. By observing the breakdown rate and damage on the surface for different electric to magnetic field ratios, we hope to reproduce the limiting RF field effects seen in various accelerator structure, waveguides and klystrons. The initial high power test has been done in SLAC. The experiment results will be discussed in the paper together with future experiments.  
 
TUP141 RF Solid State Driver for Argonne Light Source 1097
 
  • B. Popovic
    University of Iowa, Iowa City, Iowa, USA
  • G.J. Waldschmidt
    ANL, Argonne, USA
 
  Funding: 2010 Lee Teng Summer Student Program at Argonne National Laboratory
Currently, power to the APS storage ring and Booster cavities is provided from klystrons with a eventual goal to move to a solid state RF system. A modular design centered around a 1 kW amplifier has been decided on. The driver amplifier was created for this module system using Agilent’s ADS circuit simulation software and then built and tested.
 
 
TUP145 Introduction to HLSII Storage Ring Conventional Magnets 1100
 
  • H. Zhang, G. Feng, W.W. Li, W. Li, J.J. Liang, L. Wang, S.C. Zhang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  HLS (Hefei Light Source) is a dedicated synchrotron radiation research facility, whose emittance is relatively large. In order to improve the performance of HLS, especially getting higher brilliance synchrotron radiation and increasing the number of straight section for insertion devices, an upgrade project named HLSII will be proceeded soon. The storage ring lattice comprises 8 dipoles, 32 quadrupoles and 32 combined function sextupoles. Design and analysis of the magnets are showed in the paper. the multipurpose combined function magnet is the first one designed and used in China. Mechanical design and fabrication procedures for the magnets are presented also.  
 
TUP146 Large Aperture Quadrupole Magnets for ISIS TS-1 and TS-2 1103
 
  • S.M. Gurov, A.M. Batrakov, M.F. Blinov, F.A. Emanov, V.V. Kobets, V.A. Polukhin, A.S. Tsyganov, P. Vobly, T.A. Yaskina
    BINP SB RAS, Novosibirsk, Russia
  • S.J.S. Jago, J. Shih, S.F.S. Tomlinson
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  The ISIS pulsed neutron and muon source at the Rutherford Appleton Laboratory has two target stations TS-1 and TS-2. Budker Institute of Nuclear Physics developed, produced and delivered seven type Q13 quadrupole magnets with an aperture diameter of 310 mm for TS-2 beam transfer line. Later an additional three quadrupoles with integrated dipole coils were developed and delivered to ISIS TS1. To improve the field quality across the full current range a special pole profile and end chamfer were designed using the MERMAID code. The magnetic field map was measured by a set of Hall probes. Moreover, BINP produced a rotating coil with radius 120 mm for field quality measurements.  
 
TUP147 Rotating Dipole and Quadrupole Field for a Multiple Cathode System 1106
 
  • X. Chang, I. Ben-Zvi, J. Kewisch, V. Litvinenko, W. Meng, A.I. Pikin, V. Ptitsyn, T. Rao, B. Sheehy, J. Skaritka, Q. Wu
    BNL, Upton, Long Island, New York, USA
  • E. Wang
    PKU/IHIP, Beijing, People's Republic of China
  • T. Xin
    Stony Brook University, Stony Brook, USA
 
  A multiple cathode system has been designed to provide the high average current polarized electron bunches for the future electron-ion collider eRHIC. One of the key research topics in this design is the technique to generate a combined dipole and quadrupole rotating field at high frequency (700 kHz). This type of field is necessary for combining bunches from different cathodes to the same axis with minimum emittance growth. Our simulations and the prototype test results to achieve this will be presented.  
 
TUP148 Ion Trapping Study in eRHIC 1109
 
  • Y. Hao, V. Litvinenko, V. Ptitsyn
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The ion trapping effect is an important effect in energy recovery linac (ERL). The ionized residue gas molecules can accumulate at the vicinity of the electron beam pass and deteriorate the quality of the electron beam. In this paper, we present simulation results to address this issue in eRHIC and find best beam pattern to eliminate this effect.
 
 
TUP149 Magnetic Field Mapping and Integral Transfer Function Matching of the Prototype Dipoles for the NSLS-II at BNL 1112
 
  • P. He, M. Anerella, G. Ganetis, R.C. Gupta, A.K. Jain, P.N. Joshi, J. Skaritka, C.J. Spataro, P. Wanderer
    BNL, Upton, Long Island, New York, USA
 
  The National Synchrotron Light Source-II (NSLS-II) storage ring at Brookhaven National Laboratory (BNL) will be equipped with 54 dipole magnets having a gap of 35 mm, and 6 dipoles having a gap of 90 mm. The large aperture magnets are necessary to allow the extraction of long-wavelength light from the dipole magnet to serve a growing number of users of low energy radiation. The dipoles must not only have good field homogeneity (0.015% over a 40 mm x 20 mm region), but the integral transfer functions and integral end harmonics of the two types of magnets must also be matched. The 35 mm aperture dipole has a novel design where the yoke ends are extended up to the outside dimension of the coil using magnetic steel nose pieces. A Hall probe mapping system has been built with three Group 3 Hall probes mounted on a 2-D translation stage. The probes are arranged with one probe in the midplane of the magnet and the others vertically offset by ±10 mm. The field is mapped along a nominal 25 m radius beam trajectory. The results of measurements in the as-received magnets, and with modifications made to the nose pieces will be presented.  
 
TUP152 Dipole Corrector Magnets for the LBNE Beam Line 1115
 
  • M. Yu, D.J. Harding, G. Velev
    Fermilab, Batavia, USA
 
  The conceptual design of a new dipole corrector magnet has been thoroughly studied. The planned Long-Baseline Neutrino Experiment (LBNE) beam line will require correctors capable of greater range and linearity than existing correctors, so a new design is proposed based on the horizontal trim dipole correctors built for the Main Injector synchrotron at Fermilab. The gap, pole shape, length, and number of conductor turns remain the same. To allow operation over a wider range of excitations without overheating, the conductor size is increased, and to maintain better linearity, the back leg thickness is increased. The magnetic simulation was done using ANSYS to optimize the shape and the size of the yoke. The thermal performance was also modeled and analyzed.  
 
TUP153 Fabrication and Test of Short Helical Solenoid Model Based on YBCO Tape 1118
 
  • M. Yu, V. Lombardo, M.L. Lopes, D. Turrioni, A.V. Zlobin
    Fermilab, Batavia, USA
  • G. Flanagan, R.P. Johnson
    Muons, Inc, Batavia, USA
 
  Funding: Supported in part by USDOE STTR Grant DE-FG02-07ER84825 and by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
A helical cooling channel (HCC) is a new technique proposed for six-dimensional (6D) cooling of muon beams. To achieve the optimal cooling rate, the high field section of HCC need to be developed, which suggests using High Temperature Superconductors (HTS). This paper updates the parameters of a YBCO based helical solenoid (HS) model, describes the fabrication of HS segments (double-pancake units) and the assembly of six-coil short HS model with two dummy cavity insertions. Three HS segments and the six-coil short model were tested. The results are presented and discussed.
 
 
TUP161 Quench Properties of Two Prototype Superconducting Undulators for the Advanced Photon Source 1121
 
  • C.L. Doose, M. Kasa, S.H. Kim
    ANL, Argonne, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The quench properties of two 42-pole prototype superconducting undulators (SCUs) (one having a steel core the other with an aluminium core) have been tested. Since the SCUs have relatively low stored energy, the quench protection has relied on an over-voltage protection feature of the power supply, and the inherent quench back from the core. Concerns about conductor damage (during a quench) due to heating and high induced voltages were raised. The maximum conductor temperatures and voltages have been deduced from voltage and current measurements during a quench. The deduced maximum hot-spot temperature of the conductor was less than 150 K and the maximum voltage across each SCU coil was less than 300 V.
 
 
TUP162 Engineering Design of HTS Quadrupole for FRIB 1124
 
  • J.P. Cozzolino, M. Anerella, A.K. Ghosh, R.C. Gupta, W. Sampson, Y. Shiroyanagi, P. Wanderer
    BNL, Upton, Long Island, New York, USA
  • A. Zeller
    FRIB, East Lansing, Michigan, USA
 
  Funding: Supported by the U.S. Department of Energy under Contract DE-AC02-98CH10886 and under Cooperative Agreement DE-SC0000661 from DOE-SC that provides financial assistance to MSU for FRIB.
The coils of the first quadrupole in the fragment separator region of the Facility for Rare Isotope Beams (FRIB) must withstand an intense level of radiation and accommodate a very high heat load. Magnets produced with High Temperature Superconductors (HTS) are especially suitable in such an environment. The proposed design employs second generation (2G) HTS, permitting operation at ~50K. The engineering considerations this design are summarized. The goal has been to engineer a compact, readily producible magnet with a warm bore and yoke, made from radiation-resistant materials, capable of operating within the heat load limit, whose four double-layered coils will be adequately restrained under high radial Lorentz forces. Results of ANSYS finite element thermal and structural analyses of the coil clamping system are presented. Coil winding, lead routing and splicing, magnet assembly as well as remote tunnel installation/removal considerations are factored into this design and will also be discussed.
 
 
TUP163 Design Construction and Test Results of a HTS Solenoid for Energy Recovery Linac 1127
 
  • R.C. Gupta, M. Anerella, I. Ben-Zvi, G. Ganetis, D. Kayran, G.T. McIntyre, J.F. Muratore, S.R. Plate, W. Sampson
    BNL, Upton, Long Island, New York, USA
  • M.D. Cole, D. Holmes
    AES, Medford, NY, USA
 
  Funding: This work is supported by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886.
An innovative feature of the proposed Energy Recovery Linac (ERL) at Brookhaven National Laboratory (BNL) is the use of a solenoid made with High Temperature Superconductor (HTS) with the Superconducting RF cavity. The use of HTS in the solenoid offers many advantages. The solenoid is located in the transition region (4 K to room temperature) where the temperature is too high for a conventional low temperature superconductor and the heat load on the cryogenic system too high for copper coils. Proximity to the cavity provides early focusing and thus a reduction in the emittance of the electron beam. In addition, taking full advantage of the high critical temperature of HTS, the solenoid has been designed to reach the required field at ~77 K, which can be obtained with liquid nitrogen. This significantly reduces the cost of testing and allows a variety of critical pre‐tests (e.g. measurements of the axial and fringe fields) which would have been very expensive at 4 K in liquid helium because of the additional requirements for a cryostat and associated facilities. This paper will present the design, construction, test results and current status of this HTS solenoid.
 
 
TUP164 Magnetic Design of e-lens Solenoid and Corrector System for RHIC 1130
 
  • R.C. Gupta, M. Anerella, W. Fischer, G. Ganetis, A.K. Ghosh, X. Gu, A.K. Jain, P. Kovach, A. Marone, A.I. Pikin, S.R. Plate, P. Wanderer
    BNL, Upton, Long Island, New York, USA
 
  Funding: This work is supported by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886.
As a part of the proposed electron lens system for RHIC, two 6 T, 200 mm aperture, 2.5 meter long superconducting solenoids are being designed and built at BNL. Because of several demanding requirements this has become a unique and technologically advanced magnet. For example, the field lines on axis must be straight over the length of the solenoid within ±50 microns. Since this is beyond the normal construction techniques, a correction package becomes an integral part of the design for which a new design has been developed. In addition, a minimum of 0.3 T field is required along the electron beam trajectory in the space between magnets. To achieve this fringe field superconducting solenoidal coils have been added at the two ends of the main solenoid. The main solenoid itself is a challenging magnet because of the high Lorentz forces and stored energy associated with the large aperture and high fields. An innovative structure has been developed to deal with the large axial forces at the ends. This paper will summarize the magnetic design and optimization of the entire package consisting of the main solenoid, the fringe field solenoids, and the corrector system.
 
 
TUP165 Design, Construction and Test of Cryogen-Free HTS Coil Structure 1133
 
  • H.M. Hocker, M. Anerella, R.C. Gupta, S.R. Plate, W. Sampson, J. Schmalzle, Y. Shiroyanagi
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by the U.S. Dept. of Energy under Contract No. DE-AC02-98CH10886 & under Coop. Agreement DE-SC0000661 from DOE-SC that provides financial assistance to MSU to design and establish FRIB
This paper will describe design, construction and test results of a cryo-mechanical structure to study coils made with the second generation High Temperature Superconductor (HTS) for the Facility for Rare Isotope Beams (FRIB). A magnet comprised of HTS coils mounted in a vacuum vessel and conduction-cooled with Gifford-McMahon cycle cryocoolers is used to develop and refine design and construction techniques. The study of these techniques and their effect on operations provides a better understanding of the use of cryogen free magnets in future accelerator projects. A cryogen-free, superconducting HTS magnet possesses certain operational advantages over cryogenically cooled, low temperature superconducting magnets.
 
 
TUP166 Novel Quench Detection System For HTS Coils 1136
 
  • P.N. Joshi, S. Dimaiuta, G. Ganetis, R.C. Gupta, Y. Shiroyanagi
    BNL, Upton, Long Island, New York, USA
 
  As a part of HTS magnet R&D, small coils are being built and tested to study quench properties in a systematic manner. Fot this purpose, multi-channel quench detection, fast and slow data logger, current ramp controller and energy extraction system was developed. This system had to be flexible, compact, economical and easy to use. The system is based on LabView and FPGA hardware from National Instrument.  
 
TUP169 The Effect of Axial Stress on YBCO Coils 1139
 
  • W. Sampson, M. Anerella, J.P. Cozzolino, R.C. Gupta, Y. Shiroyanagi
    BNL, Upton, Long Island, New York, USA
  • E. Evangelou
    The Bronx High School of Science, Bronx, New York, USA
 
  Funding: This work is supported by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886.
A spiral wound “pancake” coil made from YBCO coated conductor has been stressed to a pressure of 100MPa in the axial direction at 77K. In this case axial refers to the coil so that the force is applied to the edge of the conductor. The effect on the critical current was small and completely reversible. Repeatedly cycling the pressure had no measureable permanent effect on the coil. The small current change observed exhibited a slight hysteretic behaviour during the loading cycle.
 
 
TUP170 Mechanical Design of an Alternate Structure for LARP Nb3Sn Quadrupole Magnets for LHC 1142
 
  • J. Schmalzle, M. Anerella, J.P. Cozzolino, P. Kovach, P. Wanderer
    BNL, Upton, Long Island, New York, USA
  • G. Ambrosio, M.J. Lamm
    Fermilab, Batavia, USA
  • S. Caspi, H. Felice, P. Ferracin, G.L. Sabbi
    LBNL, Berkeley, California, USA
 
  Funding: This work is supported by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886.
An alternate structure for the 120mm Nb3Sn quadrupole magnet is presently under development for use in the upgrade for LHC at CERN. The design aims to build on existing technology developed in LARP with the LQ and HQ magnets and to further optimize the features required for operation in the accelerator. The structure includes features for maintaining mechanical alignment of the coils to achieve the required field quality. It also includes a helium containment vessel and provisions for cooling with 1.9k helium. The development effort includes the assembly of a six inch model to verify required coil load is achieved. Status of the R&D effort and an update on the magnet design, including its incorporation into the design of a complete one meter long cold mass is presented.
 
 
TUP171 Influence of Proton Irradiation on Angular Dependence of Second Generation (2G) HTS 1145
 
  • Y. Shiroyanagi, G.A. Greene, R.C. Gupta, W. Sampson
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by the U.S. DOE under Contract No. DE-AC02-98CH10886 and under Cooperative Agreement DE-SC0000661 from DOE-SC that provides financial assistance to MSU to design and establish FRIB.
In the Facility for Rare Isotope Beams (FRIB), superconducting magnets will be exposed to high levels of ionizing radiation. Quadruples in the fragment separator will be exposed to radiation doses as high as ~20 MGy/yr and heat loads as high as ~10 kW/m. High temperature superconducting (HTS) tapes are good candidates for this magnet because they can be operated in the temperature range ~30-50 K to tolerate higher temperatures than low temperature superconductors. Thus, radiation damage studies of HTS tapes are crucial to ensure that they will perform satisfactorily in such a high radiation environment. Therefore, the effects of proton irradiation on second generation HTS tapes from two vendors were studied. Each sample of HTS tape from SuperPower and American Superconductor was irradiated by a 42μA, 142 MeV proton beam at the Brookhaven Linac Isotope Producer. Two of each were irradiated at 5 dose levels: 2.5, 25, 50, 75 and 100μA•hr. The angular dependence of the critical current was measured in a magnetic field at 77K. Based on these measurements, conductors from both vendors appear to satisfy the FRIB radiation-tolerance requirement of 10 years of operation.
 
 
TUP172 Studies of High-field Sections of a Muon Helical Cooling Channel with Coil Separation 1148
 
  • M.L. Lopes, V.S. Kashikhin, K. Yonehara, M. Yu, A.V. Zlobin
    Fermilab, Batavia, USA
 
  Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The Helical Cooling Channel (HCC) was proposed for 6D cooling of muon beams required for muon collider and some other applications. HCC uses a continuous absorber inside superconducting magnets which produce solenoidal field superimposed with transverse helical dipole and helical gradient fields. HCC is usually divided into several sections each with progressively stronger fields, smaller aperture and shorter helix period to achieve the optimal muon cooling rate. This paper presents the design issues of the high field section of HCC with coil separation. The effect of coil spacing on the longitudinal and transverse field components is presented and its impact on the muon cooling is evaluated and discussed. The paper also describes methods for field corrections and their practical limits.
 
 
TUP173 Progress on the Modeling and Modification of the MICE Superconducting Spectrometer Solenoids 1151
 
  • S.P. Virostek, M.A. Green, T.O. Niinikoski, S. Prestemon, M.S. Zisman
    LBNL, Berkeley, California, USA
 
  Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231.
The Muon Ionization Cooling Experiment (MICE) is an international effort sited at Rutherford Appleton Laboratory (RAL) in the UK that will demonstrate ionization cooling in a section of realistic cooling channel using a muon beam. The spectrometer solenoids are an identical pair of five-coil superconducting magnets that will provide a 4-tesla uniform field region at each end of the cooling channel. Scintillating fiber trackers within each of the 400-mm diameter magnet bore tubes will measure the emittance of the beam as it enters and exits the cooling channel. Each of the 3-meter long magnets incorporates a three-coil spectrometer magnet section and a two-coil section that matches the solenoid uniform field into the MICE cooling channel. The cold mass, radiation shield and leads are kept cold by means of a series of two-stage cryocoolers and one single-stage cryocooler. Various thermal, electrical and magnetic analyses are being carried out in order to develop design improvements related to magnet cooling and reliability. The key features of the spectrometer solenoid magnets are presented along with some of the details of the analyses.
 
 
TUP174 Warm Magnetic Field Measurements of LARP HQ Magnet 1154
 
  • X. Wang, S. Caspi, D.W. Cheng, D.R. Dietderich, H. Felice, P. Ferracin, R.R. Hafalia, J.M. Joseph, J. Lizarazo, M. Martchevskii, C. Nash, G.L. Sabbi, C. Vu
    LBNL, Berkeley, California, USA
  • G. Ambrosio, R. Bossert, G. Chlachidze, J. DiMarco, V. Kashikhin
    Fermilab, Batavia, USA
  • J. Schmalzle, P. Wanderer
    BNL, Upton, Long Island, New York, USA
 
  The US-LHC Accelerator Research Program is develop- ing and testing a high-gradient quadrupole (HQ) magnet, aiming at demonstrating the feasibility of Nb3Sn technologies for the LHC luminosity upgrade. The 1 m long HQ magnet has a 120 mm bore with a conductor-limited gradient of 219 T/m at 1.9 K and a peak field of 15 T. HQ includes accelerator features such as alignment and field quality. Here we present the magnetic measurement results obtained at LBNL with a constant current of 30 A. A 100 mm long circuit-board rotating coil developed by FNAL was used and the induced voltage and flux increment were acquired. The measured b6 ranges from 0.3 to 0.5 units in the magnet straight section at a reference radius of 21.55 mm. The data reduced from the numerical integration of the raw voltage agree with those from the fast digital integrators.  
 
TUP175 Fabrication of the Jefferson Laboratory Cryogenic Control Reservoirs 1157
 
  • M.L. Seely, E.C. Bonnema, D.J. Carvelli, E.K. Cunningham, E.C. Kasper, G.D. Korecky
    Meyer Tool & MFG, Oak Lawn, Illinois, USA
 
  Meyer Tool and Manufacturing of Oak Lawn IL is manufacturing six Cryogenic Control reservoirs CCRs) for the Jefferson Laboratory. Five of the CCRs will be installed in the new Super High Momentum Spectrometer (SHMS) planned for Jefferson Lab's Hall C and the sixth will be installed in Hall D. Both projects are part of the 12 GeV upgrade to the CEBAF accelerator . The CCRs are a cryogenic distribution box designed by the Jefferson Laboratory. They include internal reservoirs in order to provide a continuous supply liquid helium and liquid nitrogen to magnets through periods of disruption in the external supply. This paper discusses the manufacturing and process measures that were implemented in order to meet the Department of Energy requirements for pressure vessels (10CFR851 Appendix A Part 4), to eliminate brazing flux contamination, and to reduce weld distortion in multiple internal vessels. The CCRs will undergo pressure and vacuum testing at Meyer Tool before being installed by the magnet manufacturer.  
 
TUP177 Open Midplane Dipoles for a Muon Collider 1160
 
  • R.J. Weggel, J. Kolonko, R.M. Scanlan
    Particle Beam Lasers, Inc., Northridge, California, USA
  • M. Anerella, R.C. Gupta, H.G. Kirk, R. B. Palmer, J. Schmalzle
    BNL, Upton, Long Island, New York, USA
  • D.B. Cline, X.P. Ding
    UCLA, Los Angeles, California, USA
 
  Funding: This work is supported by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886 and SBIR contract DOE Grant Numbers DE-FG02-07ER84855 and DE-FG02-08ER85037.
For a muon collider with copious decay particles in the plane of the storage ring, open-midplane dipoles (OMD) may be preferable to tungsten-shielded cosine-theta dipoles of large aperture. The OMD should have its midplane completely free of material, so as to dodge the radiation from decaying muons. Analysis funded by a Phase I SBIR suggests that a field of 10-20 T should be feasible, with homogeneity of 1x10-4 and energy deposition low enough for conduction cooling to 4.2 K helium. If funded, a Phase II SBIR would refine the analysis and build and test a proof-of-principle magnet.
 
 
TUP178 Current Progress of TAMU3: A Block Coil Stress-managed High Field (>12T) Nb3Sn Dipole 1163
 
  • E.F. Holik, C.P. Benson, R. Blackburn, N. Diaczenko, T. Elliott, A. Jaisle, A.D. McInturff, P.M. McIntyre, A. Sattarov
    Texas A&M University, College Station, Texas, USA
 
  Funding: This work was supported by the U.S. Department of Energy under Grant DE-FG02-06ER41405
TAMU3 is a block-coil short model dipole which embodies for the first time at high field (>12T) strength the techniques of stress management within the superconducting windings. The dipole consists of two planar racetrack coil assemblies, assembled within the rectangular aperture of a flux return core. Each assembly contains an inner and outer winding, and a high-strength support structure which is integrated within the assembly to intercept the Lorentz stress produced from the inner winding so that it does not accumulate to produce high stress in the outer winding. Iso-static preload is applied by pressurizing a set of thin stainless steel bladders with molten Woods metal and then freezing the metal under pressure. Current technology, difficulties, and present status of construction of magnet assembly will be presented.
 
 
TUP179 Energy Deposition within Superconducting Coils of a 4 MW Target Station 1166
 
  • X.P. Ding
    UCLA, Los Angeles, California, USA
  • J.J. Back
    University of Warwick, Coventry, United Kingdom
  • R.C. Fernow, H.G. Kirk, N. Souchlas
    BNL, Upton, Long Island, New York, USA
  • K.T. McDonald
    PU, Princeton, New Jersey, USA
  • R.J. Weggel
    Particle Beam Lasers, Inc., Northridge, California, USA
 
  Funding: Work Supported by the United States Department of Energy, Contract No. DE-AC02-98CH10886.
A study of energy deposition within superconducting coils of a 4 MW target station for a neutrino factory or muon collider is presented. Using the MARS code, we simulate the energy deposition within the environment surrounding the target. The radiation is produced by interactions of intense proton beams with a free liquid mercury jet. We study the influence of different shielding materials and shielding configurations on the energy deposition in the superconducting coils of the target/capture system. We also examine energy depositions for alternative configurations that allow more space for shielding, thus providing more protection for the superconducting coils.
 
 
TUP181 A Monitoring System for CSR Power Supply 1169
 
  • W. Zhang, S. An, S. Gou, W.M. Qiao, Y.P. Wang, F. Yang, Y.J. Yuan
    IMP, Lanzhou, People's Republic of China
 
  This article elaborated the monitoring system which has applied in the CSR power supply. This system is composed of the hardware and the software. The hardware is composed of PS6040-PXI-18 PXI engine case +PXI-3800 the master controller +PXI-6133 the ADC card. The software uses NI Corporation's LABVIEW to carry on the data demonstration and the analysis. This monitoring system in the CSR debugging, in the acceptance and the running has played the influential role. At the same time, it provided the data for the physical person. This monitoring system has run four years in the CSR.  
 
TUP182 In-situ System Identification for an Optimal Control of Magnet Power Supplies 1172
 
  • X.H. Ke, F. Jenni
    FHNW, Windisch, Switzerland
 
  Funding: Paul Scherrer Institute, Switzerland
In particle accelerators, the magnet power supply system (controller, power stage and magnet) normally has a higher system order (>5). An exact model, representing the behavior of such a system, would be very helpful for an optimal control. For the control, the engineers are mainly not interested in the analytic model, which shows the exact internal mechanisms of the physical system, but, in a model describing the I/O behavior. Moreover, since the real elements do not exactly correspond to the design values, it is desirable to model the power supply system by means of system identification from measured properties. For that, a subspace based identification method is applied, which yields the observer for the self-optimizing high dynamic control of magnet power supplies at the Paul Scherrer Institute (PSI). The only inputs the identification needs are the measured DC-link voltage, the magnet voltage and the magnet current. With that it calculates a corresponding state space model for the system. The whole process is done automatically and in situ, which is a practical and meaningful approach to obtain the exact system information for control design.
 
 
TUP183 Self-optimizing High Dynamic Power Supply Control 1175
 
  • X.H. Ke, F. Jenni
    FHNW, Windisch, Switzerland
  • H. Jäckle
    PSI, Villigen, Switzerland
 
  Funding: Paul Scherrer Institute, Switzerland
In 1999, the first fully digitally controlled magnet power supplies were put into operation at PSI (Paul Scherrer Institute, Switzerland). Today, approximately 1000 are in use at PSI and a multiple of that worldwide. This project aims at developing a high performance control scheme for a better dynamic behavior of today's magnet powers supplies, without reducing their excellent static behaviors. The resulting control strategy, an in situ identification based observer, combined with state space and proportional integral (SS-PI) control, leads to a significantly improved dynamic behavior of the existing power supplies. The whole commissioning, including system identification, as well as control parameter determination and optimization, is done automatically on the DSP with support of a PC. The control strategy has been implemented on the existing PSI controller and a 10A-corrector power supply, together with various magnets, by updating the software and/or firmware only. Currently, the new control strategy is being implemented and tested at PSI on a second generation Digital Power Electronic Control System (DPC) controller card.
 
 
TUP188 A New Power Supply System for the IEX Project at the APS 1178
 
  • B. Deriy, M.S. Jaski, J. Wang
    ANL, Argonne, USA
 
  A new beamline providing circularly polarized x-rays that will cover photon energies from 250 eV to 2.5 keV is under development at the APS. Because of the unique requirements of the circular polarizing undulator constructed for this beamline, a new power supply system design is required. The undulator will contain twelve sets of electromagnetic coils – two main, two quasi-periodic, and eight correctors. The undulator will incorporate variable polarization control and reduction of the magnetic fields at so-called quasi-periodic pole locations for the purpose of suppressing the higher-order radiation harmonics. The challenges met in the power supply system design for the project will be discussed.  
 
TUP190 Upgrade of the APS Booster Synchrotron Magnet Ramp 1181
 
  • C. Yao, B. Deriy, G. Feng, H. Shang, J. Wang
    ANL, Argonne, USA
 
  Funding: Work supported by U.S. Department of Energy, Offices of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06-CH11357
The APS booster is a 7-GeV electron synchrotron with 0.5-second cycle time. Both voltage and current ramp modes were in the original design but only the voltage ramp has been commissioned. Two software-based ramp control programs are used to regulate the current waveform to a linear ramp. The system has been operated for user beam operations for many years. Some instability exists in the ramp correction that requires manual intervention from time to time by the operators. Sensitivity of magnet currents to external changes, such as AC line voltage, harmonic interference from the high-power rf system, etc., has been observed. In order to meet the increased single-bunch-charge requirement of the APS upgrade we need more flexible current ramps such as flat porches for injection and extraction and smooth transitions. Recent efforts to develop an energy-saving operation mode also call for ramp improvement. This paper presents test results of a workstation-based current regulation program and an FPGA-based implementation as a future upgrade.
 
 
TUP191 Booster Main Magnet Power Supply, Present Operation and Potential Future Upgrades 1184
 
  • E.M. Bajon, M. Bannon, G. Danowski, I. Marneris, J. Sandberg, S. Savatteri
    BNL, Upton, Long Island, New York, USA
 
  Funding: *Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The Brookhaven Booster Main Magnet Power Supply (MMPS) is a 24 pulse thyristor control supply, rated at 5500 Amps, ±2000 Volts, or 3000 Amps, ±6000 Volts. The power supply is fed directly from the power utility and the peak magnet power is 18 MWatts. This peak power is seen directly at the incoming ac line. This power supply has been in operation for the last 18 years. This paper will describe the present topology and operation of the power supply, the feedback control system and the different modes of operation of the power supply. Since the power supply has been in operation for the last 18 years, upgrading this power supply is essential. A new power supply topology has been studied where energy is stored in capacitor banks. DC to DC converters are used to convert the dc voltage stored in the capacitor banks to pulsed DC voltage into the magnet load. This enables the average incoming power from the ac line to be constant while the peak magnet power is pulsed to ± 18 MWatts. Simulations and waveforms of this power supply will be presented.
 
 
TUP193 NSLS-II Power Supply Controller 1187
 
  • W. Louie, L.R. Dalesio, G. Ganetis, Y. Tian
    BNL, Upton, Long Island, New York, USA
 
  This paper presents the design of the National Synchrotron Light Source II (NSLS-II) Power Supply Controller (PSC). It consists of a main board, rear module and backplane. The main features of NSLS-II PSC included 256MB DDR2 memory for power supply system diagnostics, high speed serial link between PSC modules, an embedded microprocessor and a 100 Mbps Ethernet port. Each PSC module can be remotely programmed through network. NSLS-II PSC will be used to control power supplies in Storage Ring, Booster Ring and Transport line. The PSC also provides interface for the NSLS-II fast and slow orbits feedback system.  
 
TUP195 Commissioning the ALS Digital Power Supply Controller in the Booster Dipole and Quadrupole Magnet Power Supplies 1190
 
  • J.M. Weber, T. Scarvie, C. Steier, CA. Timossi
    LBNL, Berkeley, California, USA
 
  Funding: Supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Advanced Light Source (ALS) is a third generation synchrotron light source that has been operating since 1993 at Berkeley Lab. A few years ago, the ALS was upgraded to achieve Top-Off Mode, which required replacing the booster dipole and quadrupole magnet power supplies to increase the peak booster beam energy from 1.5GeV to 1.9GeV. The original analog controller for each power supply has been replaced by a digital power supply controller (DPSC) to improve stability and resolution and provide a remote interface. The DPSC capabilities include 24-bit 100k-point digital reference waveform download and voltage reference generation, and complete digital current loop implementation. The hardware includes an FPGA with an embedded processor running a full EPICS IOC on VxWorks. This paper will present the current functionality of the DPSC as well as performance results from recent commissioning.

 
 
TUP196 SLAC P2 MARX Control System and Regulation Scheme 1193
 
  • D.J. MacNair, M.A. Kemp, K.J.P. Macken, M.N. Nguyen, J.J. Olsen
    SLAC, Menlo Park, California, USA
 
  Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515
The SLAC P2 MARX P2 Modulator consists of 32 cells charged in parallel by a -4000V supply and discharged in series to provide a -120 KV 140 amp 1.6 millisecond pulse. Each cell has a 350uF main storage capacitor. The voltage on the capacitor will droop approximately 640 volts during each pulse. Each cell will have a boost supply that can add up to 700V to the cell output. This allows the output voltage of the cell to remain constant within 0.1% during the pulse. The modulator output voltage control is determined by the -4KV charging voltage. A voltage divider will measure the modulator voltage on each pulse. The charging voltage will be adjusted by the data from previous pulses to provide the desired output. The boost supply in each cell consists of a 700V buck regulator in series with the main capacitor. The supply uses a lookup table for PWM control. The lookup table is calculated from previous pulse data to provide a constant cell output. The paper will describe the modulator and cell regulation used by the MARX modulator. Measured data from a single cell and three cell string will be included.
 
 
TUP200 Spatial and Temporal Shaping of Picoseconds Drive Laser in Photocathode RF Gun 1196
 
  • Z.G. He, Q.K. Jia
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  In this paper, we present experimental spatial and temporal drive laser shaping results by using of a pi-shaper sample and an interferometer setup pulse stacking system. Based on the spatial and temporal shaping results, a scheme for quasi-ellipsoidal shaping and the evolution of critical parameters are also studied.  
 
TUP202 Non-Scaling FFAG Proton Driver for Project X 1199
 
  • C. Johnstone, D.V. Neuffer
    Fermilab, Batavia, USA
  • M. Berz, K. Makino
    MSU, East Lansing, Michigan, USA
  • L.J. Jenner, J. Pasternak
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • P. Snopok
    IIT, Chicago, Illinois, USA
 
  The next generation of high-energy physics experiments requires high intensity protons at multi-GeV energies. Fermilab’s HEP program, for example, requires an 8-GeV proton source to feed the Main Injector to create a 2 MW neutrino beams in the near term and would require a 4 MW pulsed proton beam for a potential Neutrino Factory or Muon Collider in the future. High intensity GeV proton drivers are difficult at best with conventional re-circulating accelerators, encountering duty cycle and space-charge limits in the synchrotron and machine size and stability concerns in the weaker-focusing cyclotrons. Only an SRF linac, which has the highest associated cost and footprint, has been considered. Recent innovations in FFAG design, however, have promoted another re-circulating candidate, the Fixed-field Alternating Gradient accelerator (FFAG), as an attractive, but as yet unexplored, alternative. Its strong focusing optics coupled to large transverse and longitudinal acceptances would serve to alleviate space charge effects and achieve higher bunch charges than possible in a synchrotron and presents an upgradeable option from the 2 MW to the 4 MW program.  
 
TUP207 The Effects of the RHIC E-lenses Magnetic Structure Layout on the Proton Beam Trajectory 1202
 
  • X. Gu, W. Fischer, R.C. Gupta, J. Hock, Y. Luo, M. Okamura, A.I. Pikin, D. Raparia
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
We are designing two electron lenses (E-lens) to compensate for the large beam-beam tune spread from proton-proton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC). They will be installed in RHIC IR10. First, the layout of these two E-lenses is introduced. Then the effects of e-lenses on proton beam are discussed. For example, the transverse fields of the e-lens bending solenoids and the fringe field of the main solenoids will shift the proton beam. For the effects of the e-lens on proton beam trajectory, we calculate the transverse kicks that the proton beam receives in the electron lens via Opera at first. Then, after incorporating the simplified E-lens lattice in the RHIC lattice, we obtain the closed orbit effect with the Simtrack Code.
 
 
TUP208 DESIGNING A BEAM TRANSPORT SYSTEM FOR RHIC’S ELECTRON LENS 1205
 
  • X. Gu, W. Fischer, R.C. Gupta, J. Hock, Y. Luo, M. Okamura, A.I. Pikin, D. Raparia
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
We designed two electron lenses to apply head-on beam-beam compensation for RHIC; they will be installed near IP10. The electron-beam transport system is an important subsystem of the entire electron-lens system. Electrons are transported from the electron gun to the main solenoid and further to the collector. The system must allow for changes of the electron beam size inside the superconducting magnet, and for changes of the electron position by 5 mm in the horizontal- and vertical-planes.
 
 
TUP211 Compensation of Fast Kicker Rolls with Skew Quadrupoles 1208
 
  • I. Pinayev
    BNL, Upton, Long Island, New York, USA
 
  The development of the third generation light sources lead to the implementation of the top-up operation, when injection occurs while users collect data. The beam excursions due to the non-closure of the injection bump can spoil the data and need to be suppressed. In the horizontal plane compensation can be achieved by adjusting timing and kick amplitudes. The rolls of the kicker magnets create non-closure in the vertical plane and usually there is no means for correction. In the paper we describe proposed compensation scheme utilizing two skew quadrupoles placed inside the injection bump.  
 
TUP213 Research and Development toward the RHIC Injection Kicker Upgrade 1211
 
  • W. Zhang, W. Fischer, H. Hahn, C. Pai, J. Sandberg, J.E. Tuozzolo
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A research and development work is on going toward the upgrade of the RHIC Injection Fast Kicker System. We report here the proposed nano-second pulse generator, the initial test result, the options of the deflector design, injection pattern, and the benefit to the future RHIC programs.
 
 
TUP216 Design of a Helium Phase Separator with Condenser 1214
 
  • F. Z. Hsiao, T.Y. Huang, C.P. Liu, H.H. Tsai
    NSRRC, Hsinchu, Taiwan
 
  This paper presents the design of a helium phase separator with volume of 100 litres. A condenser using a cryocooler for cooling is built into the phase separator to save liquid helium consumption during the test period. The heat loss to the 4.2 K inner vessel is confined within 1W due to the limited 1.5W cooling capacity from the cryocooler. Analysis of mechanical strength and heat load is illustrated.  
 
TUP217 The Application of 400KW DC Bank for Cryogenic System at NSRRC 1217
 
  • H.C. Li, S.-H. Chang, W.-S. Chiou, F. Z. Hsiao, T.F. Lin, H.H. Tsai
    NSRRC, Hsinchu, Taiwan
 
  There will be a power sag (>50% drop) several times and annual maintenance of power company every year that course cryogenic system shutdown and take hours to recover. We install the AC UPS to maintain a steady power supply to the control circuit and low power devices to avoid such incidences. However, the AC UPS is not suitable for the 315-kW compressor with inverter due to the harmonic distortion effect and low power factor. We built two sets of 400-kW DC UPS (also called DC Bank system) to keep two 315-kW compressor in full load operation at least 3 minutes when power sag or power cut-off in 2010. The DC Bank was parallel connect to the inverter, thus, will not affect the inverter operation when DC Bank need to maintenance or failure. This paper presents the configuration of DC Bank and the test of the system. Results show that when the inverter is operated at 242KW with main power cut off, the helium compressor is keeping stable operation for 257 seconds by DC Bank support.  
 
TUP218 Design of a Liquid Helium Transfer System for the TPS Project 1220
 
  • H.H. Tsai, M.H. Chang, S.-H. Chang, W.-S. Chiou, F. Z. Hsiao, H.C. Li, M.-C. Lin, T.F. Lin, C.P. Liu, Ch. Wang
    NSRRC, Hsinchu, Taiwan
 
  The construction of the Taiwan Photon Source (TPS) storage ring is under way, to be completed in mid 2012. The new helium cryogenic system is provided from the Linde Company, to be installed after the TPS storage ring is completed. The super conducting radio frequency (SRF) cavities is needed to maintain the electron energy of storage ring and were operated at refrigeration mode such that the cold helium gas from the cavity cryostat is returned to the refrigerator. One distribution valve box and individual segments of multichannel transfer lines is required to supply the liquid helium and liquid nitrogen to the SRF cavities and recover the gas helium and gas nitrogen back to the cryogenic system. This paper is aimed to present the configuration and design features of the LHe transfer system. The heat load and pressure drop calculation of the transfer system was also presented.  
 
TUP219 Temperature-Dependent Calibration of Hall Probes at Cryogenic Temperature 1223
 
  • M. Abliz, C.L. Doose, Y. Ivanyushenkov, I. Vasserman
    ANL, Argonne, USA
 
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Short-period superconducting undulators (SCUs) are presently being developed for the Advanced Photon Source. Field measurements of the SCUs will be performed at 4.2 K and near 300 K, so temperature-dependent calibration of the Hall probes is necessary. The sensitivity of the Hall probes has been measured at temperatures from 5 K to 320 K over a magnetic field range of ␣1.5 T. It was found that the sensitivity increased as the temperature decreased from 300 K to about 150 K. A specially designed probe assembly, with three Hall sensors for measuring both the horizontal and vertical field components, has been calibrated. The techniques for doing the calibration and the measurement results at various temperatures will be presented.
 
 
TUP220 Cryogenic Sub-System for the 56 MHz SRF Storage Cavity for RHIC 1226
 
  • Y. Huang, D.L. Lederle, L. Masi, P. Orfin, T.N. Tallerico, P. Talty, R. Than, Y. Zhang
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A 56 MHz Superconducting RF Cavity is being constructed for the RHIC collider. This cavity is a quarter wave resonator that will be operated at 4.4K. The cavity requires an extreme quiet environment to maintain its operating frequency. The cavity besides being engineered for a mechanically quiet system, also requires a quiet cryogenic system. Liquid helium is taken from RHIC's main helium 3.5 atm, 4.9K supply header to supply this sub-system and the boil-off is return to a separate local compressor system nearby. To acoustically separate the cryogenics' delivery and return lines, a condenser/boiler heat exchanger is used to re-liquefy the helium vapor generated by the cavity. A system description and operating parameters is given about the cryogen delivery sub-system.
 
 
TUP221 Helium Pressures in RHIC Vacuum Cryostats and Relief Valve Requirements from Magnet Cooling Line Failure 1229
 
  • C.J. Liaw, R. Than, J.E. Tuozzolo
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A catastrophic failure of the RHIC magnet cooling lines, similar to the LHC superconducting bus failure incident, would pressurize the insulating vacuum in the magnet and transfer line cryostats. Insufficient relief valves on the cryostats could cause a structural failure. A SINDA/FLUINT® model, which simulated the 4.5K/ 4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the vacuum cryostat and discharging via the reliefs into the RHIC tunnel, had been developed to calculate the helium pressure inside the cryostat. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces were included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Existing relief valve sizes were reviewed to make sure that the maximum stresses, caused by the calculated maximum pressures inside the cryostats, did not exceed the allowable stresses, based on the ASME Code B31.3 and ANSYS results.
 
 
TUP222 Helium Release Rates and ODH Calculations from RHIC Magnet Line Cooling Line Failure 1232
 
  • C.J. Liaw, R. Than, J.E. Tuozzolo
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A catastrophic failure of the magnet cooling lines, similar to the LHC superconducting bus failure incident, could discharge cold helium into the RHIC tunnel and cause an Oxygen Deficiency Hazard (ODH) problem. A SINDA/FLUINT® model, which simulated the 4.5K/ 4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the insulating vacuum volumes and discharging via the reliefs into the RHIC tunnel, had been developed. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces are included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Results, including helium discharge rates, helium inventory loss, and the resulting oxygen concentration in the RHIC tunnel area, are reported. Good agreement had been achieved when comparing the simulation results, a RHIC sector depressurization test measurement, and some simple analytical calculations.
 
 
TUP223 Cryogenic System for the Energy Recovery Linac and Vertical Test Facility at BNL 1235
 
  • R. Than, D.L. Lederle, L. Masi, P. Orfin, R. Porqueddu, V. Soria, T.N. Tallerico, P. Talty, Y. Zhang
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A small cryogenic system and warm helium vacuum pumping system provides cooling to the Energy Recovery Linac's (ERL) cryomodules, a 5-cell cavity and an SRF gun, and a large Vertical Test Dewar. The system consist of a model 1660S PSI (KPS) plant, a 4000 liter storage dewar, subcooler, wet expander, 50 g/s main helium compressor and 170 m3 storage tank. A system description and operating plan is given of the cryogenic plant and cryomodules
 
 
TUP224 Cryogenic Vertical Test Facility for the SRF Cavities at BNL 1238
 
  • R. Than, I. Ben-Zvi, A. Burrill, M.C. Grau, D.L. Lederle, C.J. Liaw, G.T. McIntyre, D. Pate, R. Porqueddu, T.N. Tallerico, J.E. Tuozzolo
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
A vertical facility has been constructed to test SRF cavities and can be utilized for other use. The liquid helium volume for the large vertical dewar is approximate 84 inches tall by 40 inches diameter with a working clear inner diameter of 38 inch with the inner cold magnetic shield system installed. For radiation enclosure, the test dewar is situated inside a concrete block structure. The structure is above ground and is accessible from the top, and has a retractable concrete roof. A second radiation concrete facility, with ground level access via a labyrinth is also available for testing of smaller cavities in 2 smaller dewars.
 
 
TUP225 Overview of Recent Studies and Modifications Being Made to RHIC to Mitigate the Effects of a Potential Failure to the Helium Distribution System 1241
 
  • J.E. Tuozzolo, D. Bruno, A. Di Lieto, G. Heppner, R. Karol, E.T. Lessard, C.J. Liaw, G.T. McIntyre, C. Mi, J. Reich, J. Sandberg, S.K. Seberg, L. Smart, T.N. Tallerico, R. Than, C. Theisen, R.J. Todd, R. Zapasek
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In order to cool the superconducting magnets in RHIC, its helium refrigerator distributes 4.5 K helium throughout the tunnel via a series of distribution and return lines. The worst case for failure would be a release from the magnet distribution line, which operates at 3.5 to 4.5 atmospheres and contains the energized magnet bus. Should the bus insulation system fail or an electrical connection open, there is the potential for releasing up to 70 MJoules of stored energy. Studies were done to determine release rate of the helium and the resultant reduction in O2 concentration in the RHIC tunnel and service buildings. Equipment and components were also reviewed for reliability and the effects of 10 years of operations. Modifications were made to reduce the likelihood of failure and to reduce the amount of helium gas that could be released into tunnels and service buildings while personnel are present. This paper describes the issues reviewed, the steps taken, and remaining work to be done to reduce the hazards.
 
 
TUP227 Status of NSLS-II Storage Ring Vacuum Systems 1244
 
  • H.-C. Hseuh, A. Blednykh, L. Doom, M.J. Ferreira, C. Hetzel, J. Hu, S. Leng, C. Longo, V. Ravindranath, K. Roy, S.K. Sharma, F.J. Willeke, K. Wilson, D. Zigrosser
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work performed under the auspices of U.S. Department of Energy, under contract DE-AC02-98CH10886
National Synchrotron Light Source II (NSLS-II), being constructed at Brookhaven National Laboratory, is a 3- GeV, high-flux and high-brightness synchrotron radiation facility with a nominal current of 500 mA. The storage ring vacuum system has extruded aluminium chambers, with ante-chamber for photon fans and distributed NEG strip pumping. Discrete photon absorbers are used to intercept the un-used bending magnet radiation. In-situ bakeout is implemented to achieve fast conditioning during initial commissioning and after interventions.
 
 
TUP228 Design of the EBIS Vacuum System 1247
 
  • M. Mapes, L. Smart, D. Weiss
    BNL, Upton, Long Island, New York, USA
 
  At Brookhaven National Labratory the Electron Beam Ion Source (EBIS) is presently being commisioned. The EBIS will be a new heavy ion pre-injector for the Realativistic Heavy Ion Collider (RHIC). The new pre-injector has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium. The background pressure in the ionization region of the EBIS should be low enough that it does not produce a significant number of ions from background gas. The pressure in the regions of the electron gun and electron collector can be higher than in the ionization region provided there is efficient vacuum separation between the sections. For injection the ions must be accelerated to 100KV by pulsing the EBIS platform. All associated equipment including the vacuum equipment on the platform will be at a 100KV potential. The vacuum system design and the vacuum controls for the EBIS platform and transport system will be presented as well as the interface with the Booster Ring which has a pressure 10-11 Torr.  
 
TUP229 Implementation and Operation of Electron Cloud Diagnostics for CesrTA 1250
 
  • Y. Li, J.V. Conway, X. Liu, V. Medjidzade, M.A. Palmer
    CLASSE, Ithaca, New York, USA
 
  Funding: Work Supported by NSF Grant #PHY-0734867 & DOE Grant #DE-FC02-08ER41538
The vacuum system of Cornell Electron Storage Ring (CESR) was successfully reconfigured to support CesrTA physics programs, including electron cloud (EC) build-up and suppression studies. One of key features of the reconfigured CESR vacuum system is the flexibility for exchange of various vacuum chambers with minimized impact to the accelerator operations. This is achieved by creation of three short gate-valve isolated vacuum sections. Over the last three years, many vacuum chambers with various EC diagnostics (such as RFAs, shielded pickups, etc) were rotated through these short experimental sections. With these instrumented test chambers, EC build-up was studied in many magnetic field types, including dipoles, quadrupoles, wigglers and field-free drifts. EC suppression techniques by coating (TiN, NEG and amorphous-C), surface textures (grooves) and clearing electrode are incorporated in these test chambers to evaluate their vacuum performance and EC suppression effectiveness. We present the implementation and operations of EC diagnostics.
 
 
TUP230 In-situ Secondary Electron Yield Measurement System at CesrTA 1253
 
  • Y. Li, J.V. Conway, S. Greenwald, J.-S. Kim, V. Medjidzade, T.P. Moore, M.A. Palmer, C.R. Strohman
    CLASSE, Ithaca, New York, USA
  • D. Asner
    Carleton University, College of Natural Sciences, Ottawa, Ontario, Canada
 
  Funding: Work Supported by NSF Grant #PHY-0734867 & DOE Grant #DE-FC02-08ER41538
Measuring the secondary electron yield (SEY) on technical surfaces in accelerator vacuum systems provides essential information for the study of electron cloud growth and suppression, with application to many accelerator R&D projects. As a part of the CesrTA research program, we developed and deployed an in-situ SEY measurement system. A two-sample SEY system was installed in the CesrTA vacuum system with one sample exposed to direct synchrotron radiation (SR) and the other sample exposed to scattered SR. The SEYs of both samples were measured as a function of the SR dosages. In this paper, we describe the in-situ SEY measurement systems and the initial results on bare aluminum (6061-T6), TiN-coated aluminum, amorphous carbon-coated aluminum, and amorphous carbon-coated copper samples.
 
 
TUP231 Applications of Textured Dysprosium Concentrators in Ultra-Short Period Insertion Devices 1256
 
  • A.Y. Murokh, R.B. Agustsson, P. Frigola
    RadiaBeam, Santa Monica, USA
  • O.V. Chubar, V. Solovyov
    BNL, Upton, Long Island, New York, USA
 
  The next generation light sources require development of the insertion devices with shorter periods and higher peak field values, well beyond the presently available designs limited by magnetic properties of conventional materials. Dysprosium (Dy) is a rare earth metal with unique ferromagnetic properties below 90 K, including saturation inductance above 3.4 Tesla. However, due to the high magnetic anisotropy of Dy, such a high level of magnetization can only be realized when the external field lies in the basal plane. This requirement is partially satisfied in the textured dysprosium presently under development at RadiaBeam and BNL. Textured Dy development status is discussed, as well as potential applications as field concentrators in the insertion devices, with particular emphasis on the next generation of cryogenically cooled short period hybrid undulators.  
 
TUP232 Super-Conducting Wigglers and the Effect on Injection Efficiency 1259
 
  • M.J. Sigrist, L.O. Dallin, W.A. Wurtz
    CLS, Saskatoon, Saskatchewan, Canada
 
  The Canadian Light Source has two superconducting wigglers (SCW) operating at 2.1T and 4.3T peak fields. Injection efficiency into the storage ring is reduced by either device operating at high fields. Currently the CLS operates with a Fill and Decay mode, injecting with both wigglers at reduced field to avoid low injection efficiencies. Future implementation of a Top-up mode will require both wigglers to be operating at full field and better injection efficiencies will be required. Simulations and experiments have shown that the poor injection efficiency is related to operating a high vertical chromaticity. Much improved efficiencies are observed at when the chromaticity is lowered. As well, small improvements to the injection efficiency have been achieved through local correction of the beta-beats and tune shifts caused by the wigglers and optimisation of the injection co-ordinates of the injected beam. Measurements of the injection efficiencies at various chromaticities will be presented along with the betatron oscillations before and after correction.  
 
TUP235 Strategy for Neutralizing the Impact of Insertion Devices on the MAX IV 3 GeV Ring 1262
 
  • E.J. Wallén, S.C. Leemann
    MAX-lab, Lund, Sweden
 
  In order to prepare for the potentially negative influence on the beam lifetime, injection efficiency and beam size from the insertion devices (IDs) on the stored beam of the MAX IV 3 GeV storage ring strategy for neutralizing the foreseen effects of the IDs has been developed. In short the strategy involves a local correction of the betatron phase advance by adjusting the strength of the quadrupoles adjacent to the ID. There will also be a global tune correction in order to avoid drift in the working point of the storage ring during operation. Air coils with empirical feed forward tables for the excitation current in the coils will compensate for field integral errors. The lattice of the MAX IV 3 GeV storage ring appears to be robust and it tolerates the dynamic multipoles created by the expected initial set of IDs provided that the local correction of the betatron phase advance has been carried out.  
 
TUP236 Progress of a Gradient Damping Wiggler of the ALPHA Storage Ring 1265
 
  • C.W. Huang, D.J. Huang
    NTHU, Hsinchu, Taiwan
  • S.D. Chen
    NCTU, Hsinchu, Taiwan
  • M.-H. Huang, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin, Y.T. Yu
    NSRRC, Hsinchu, Taiwan
  • S.-Y. Lee
    IUCF, Bloomington, Indiana, USA
 
  The main purpose of a gradient damping wiggler (GDW) to be installed in the Alpha storage ring in Indiana University is to correct the momentum-compaction factor and the damping partition in the Alpha storage ring. One middle pole and two outer poles in one set of the GDW are installed on the same girder. Two sets of GDW will be installed in the two short straight sections. The dipole and gradient-field strengths of the middle (outer) pole are 0.67 T (-0.67 T) and 1.273 T m-1 (1.273 T m-1), respectively. One completed set of GDW is already fabricated; we shall add an end shim to improve the region of effective good field within which the middle and outer poles along the transverse x-axis (△B/B = 0.1 %) are ±50 and ±40 mm respectively. We used a trim coil on the three poles to adjust the first and second integral fields to zero. Here we discuss the integral magnetic field features along the straight trajectory and the ideal orbital trajectory with a Hall probe mapping system, and present an analysis of the magnetic field.  
 
TUP237 Development of Accurate and Precise In-Vacuum Undulator System 1268
 
  • A. Deyhim, J.D. Kulesza
    Advanced Design Consulting, Inc, Lansing, New York, USA
  • K.I. Blomqvist
    MAX-lab, Lund, Sweden
 
  Typical in-vacuum undulators, especially long ones, have several associated engineering challenges to be accurate and precise; magnetic centerline stability, inner girder hangers, and magnet period to name a few. The following describes these issues in more detail and ADC’s methods solved these critical issues for long in vacuum undulators. ADC has designed, built and delivered Insertion Devices and Magnetic Measurement Systems to such facilities as; MAXLab (EPU, Planar-2, and Measurement System), ALBA and Australian Synchrotron Project (Wiggler), BNL (Cryo In-Vacuum), SSRF (In-Vacuum – 2, and Measurement System), PAL (In-Vacuum and Measurement System), NSRRC (In-Vacuum), and SRC (Planar and EPU). The information presented here uses data from a recent IVU we delivered to PAL. This IVU will be installed at Pohang Accelerator Laboratory (PAL) for U-SAXS (Ultra Small Angle X-ray Scattering) beamline in 2011. The IVU generates undulator radiation up to ~14 keV using higher harmonic (up to 9th) undulator radiation with 2.5 GeV PLS electron beam  
 
TUP238 Development of an Integrated Field Measurement System (IFMS) for NSLS II 1271
 
  • A. Deyhim, S.W. Hartman, J.D. Kulesza
    Advanced Design Consulting, Inc, Lansing, New York, USA
 
  This paper describes the mechanical design, control instrumentation and software for the Integrated Field Measurement System (IFMS) for the Magnetic Measurement Lab for the National Synchrotron Light Source II (NSLS-II) project at Brookhaven National Laboratory. Insertion devices (IDs) at NSLS II need to be accurately surveyed using an integrated field measurement system prior to insertion into the storage ring and can also be used in the tunnel for final tuning of IDs. It is a fast and precise measurement system required in determining the ID magnetic field integrals. The design is a set of long coils supported by two 3-axis X-Y-Z precision linear and two precision rotary positioning stages. The PC is the primary control unit. Eight stepping motor control cards, eight drivers, one digital I/O board, one 6U PXI card, and one integrator are installed to perform remote control and data acquisition.  
 
TUP239 Development of a Super-Mini Undulator 1274
 
  • A. Deyhim, J.D. Kulesza
    Advanced Design Consulting, Inc, Lansing, New York, USA
  • C. Diao, H.O. Moser
    SSLS, Singapore, Singapore
 
  This paper describes development and initial results for a small prototype of a superconducting undulator with a period less than 1 cm, referred to here as a “super-mini” undulator. The development of superconducting mini-undulators started in the early 1990s with work at BNL and KIT (Germany). In 1998, KIT demonstrated the first photon production with a super-mini of 3.8 mm period length *. This super-mini consisted of two coils wound bi-filarly in analogy to a solenoid. If such coils are arranged alongside each other, separated only by a small gap of the order of a couple of millimeters, a spatially alternating magnetic field is produced that makes a passing electron beam undulate and emit undulator radiation. Owing to the short period length, the photon energy is much higher than with conventional undulators at the same electron energy. Likewise, for a given photon energy, the electron energy can be much smaller entailing considerable cost savings of accelerator, building, and operations.
* T. Hezel, B. Krevet, H.O. Moser, J.A. Rossmanith, R. Rossmanith, and Th. Schneider, A superconductive undulator with a period length of 3.8 mm, J. Synchrotron Rad. 5(1998) pp. 448-450.
 
 
TUP240 Coil Energizing Patterns for an Electromagnetic Variably Polarizing Undulator 1277
 
  • R.J. Dejus, M.S. Jaski, E.R. Moog
    ANL, Argonne, USA
  • S. Sasaki
    HSRC, Higashi-Hiroshima, Japan
 
  Funding: The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”).
A new electromagnetic insertion device optimized for producing intense soft x-rays of variable polarization is under construction at the Advanced Photon Source. Most of the coil packs are powered by a main power supply; a few are powered separately so that magnetic fields at certain pole positions can be different. The undulator radiation depends sensitively on the chosen magnetic field pattern, and higher spectral harmonics may be shifted in energy. For some beamline experiments, it is important to reduce the so-called higher-order contamination to increase the signal-to-noise ratio. We present spectra and power densities calculated directly from realistic magnetic fields and discuss coil energizing patterns.
Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
 
 
TUP241 End-Field Analysis and Implementation of Correction Coils for a Short-Period NbTi Superconducting Undulator 1280
 
  • C.L. Doose, M. Kasa, S.H. Kim
    ANL, Argonne, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A short period superconducting undulator (SCU) is being developed at the Advanced Photon Source (APS). The on-axis field of the prototype 1.6-cm period 42-pole SCU0 was measured with a cryogenic Hall probe system. Typical permanent magnet undulators provide end-field correction by decreasing the strength of the magnets on both ends of each jaw. In the case of the SCU0, a set of correction coils was wound on the two end grooves of each of the steel cores along with the main coils to provide the required end fields. These correction coils were connected in series and energized with one power supply to provide simple and symmetrical operation. The measured phase errors of the SCU0 were below 2 degrees rms without any local magnetic tuning of the device.
 
 
TUP242 Electron Cloud Issues for the APS Superconducting Undulator 1283
 
  • K.C. Harkay, Y. Ivanyushenkov, R. Kustom, E.R. Moog, E. Trakhtenberg
    ANL, Argonne, USA
  • L.E. Boon, A.F. Garfinkel
    Purdue University, West Lafayette, Indiana, USA
 
  Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The APS Upgrade calls for the development and commissioning of a superconducting undulator (SCU) at the Advanced Photon Source (APS), a 7-GeV electron synchrotron. Operation of an SCU at Angstromquelle Karlsruhe (ANKA), also an electron ring, suggests that electron multipacting is consistent with the observed heat load and pressure rise, but this effect is not predicted by an electron cloud generation code. At APS it was found that while the cloud code POSINST agreed fairly well with retarding field analyzer (RFA) data for a positron beam (operated 1996-98), the agreement was less satisfactory for the electron beam. The APS data suggest that the photoelectron model is not complete. Given that the heat load is a critical parameter in designing the cryosystem for the SCU and given the experience at ANKA, a study is underway to minimize the possible contribution to the heat load by the electron cloud at the APS, the photoelectrons in particular. In this talk, the results from POSINST are presented. Preliminary tracking of the photon flux using SYNRAD3D for the APS SCU chamber is presented, and possible ways to mitigate the photoelectrons are discussed.
 
 
TUP243 Development Status of a Magnetic Measurement System for the APS Superconducting Undulator 1286
 
  • Y. Ivanyushenkov, M. Abliz, C.L. Doose, M. Kasa, E. Trakhtenberg, I. Vasserman
    ANL, Argonne, USA
  • V.K. Lev, N.A. Mezentsev, V.M. Tsukanov
    BINP SB RAS, Novosibirsk, Russia
 
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Short-period superconducting undulators are being developed as part of the Advanced Photon Source (APS) upgrade program. The first test device is in fabrication. Before installation into the storage ring, the magnetic performance of the undulators will be characterized. The magnetic measurement facility routinely used for measuring and tuning conventional undulators cannot be employed for superconducting devices, so a new measurement system is being designed and built. The system is mechanically mounted on the undulator cryostat and uses a heated tube in the cold undulator bore to guide a Hall probe or measuring coils. A specially designed three-Hall sensor assembly allows measurement of the vertical and horizontal components of the magnetic field and the determination of the height of the magnetic midplane. A set of measuring coils is mounted on carbon-fiber tubes that can be translated and rotated in the undulator bore to measure the field integrals and their multipole components. The design of the measurement system and its construction status is described in this paper.
 
 
TUP244 Magnetic Simulation of an Electromagnetic Variably Polarizing Undulator * 1289
 
  • M.S. Jaski, R.J. Dejus, E.R. Moog
    ANL, Argonne, USA
 
  Development of an all-electromagnetic variable polarizing undulator is underway at the Advanced Photon Source (APS). This device has a set of Bx poles and coils and a set of By poles and coils. The Bx coils are powered separately from the By coils. Modifying the geometry of the Bx coils or poles changes not only the Bx field but changes the By field as well and vice-versa. Magnetic modeling with OPERA 3-D software was used to optimize the coil and pole geometries. Results of the magnetic field simulation and optimization are presented in this paper.
* Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract number DE-AC02-06CH11357.
 
 
TUP245 Comparison of Standard S-Glass and Ceramic Coating as Insulation in Short-Period Superconducting Undulators Based on Nb3Sn 1292
 
  • S.H. Kim, C.L. Doose, M. Kasa, R. Kustom, E.R. Moog
    ANL, Argonne, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
This paper compares calculated on-axis fields for short- period superconducting undulators (SCUs) using Nb3Sn superconductor with two different insulation thicknesses, 0.02 mm and 0.05 mm. When the insulated conductor diameter remained the same, the on-axis fields using the thinner insulation were higher by about 8 – 15% for a period range of 15 – 10 mm. When the conductor diameters with the thicker insulation were made larger than the conductors with the thinner insulation, the differences were reduced to be about 6 – 12%.
 
 
TUP248 SC Undulator with the Possibility To Change Its Strength and Polarization by Feeding Current 1295
 
  • A.A. Mikhailichenko
    CLASSE, Ithaca, New York, USA
 
  Funding: NSF
We describe the design of optimized undulator with SC windings able to generate the magnetic field of opposite helicities, including an elliptic and a linear ones oriented as desired. For the undulator period 25mm and aperture 8mm, K factor could be changed from zero up to 1.5 by changing the feeding current. Polarization changed by changing the currents in additional helical windings.
 
 
TUP253 AGS Tune Jump Power Supply Design and Test 1298
 
  • J.-L. Mi, J.W. Glenn, H. Huang, I. Marneris, P.J. Rosas, J. Sandberg, Y. Tan, W. Zhang
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A horizontal tune jump system has been installed to overcome the horizontal intrinsic spin resonances, which requires jumping the horizontal tune 0.04 units 82 times, 41 up and 41 down. Two quadruple magnets have been installed in AGS ring to do this. The pulsed magnet currents range from about 140 amps near injection to about 1400 amps late. Current pulse rise and fall times are around 100 micro-sec and flat tops time are around 4mS. These quadruples have separate supplies. This tune jump pulse power supply employees all semiconductor parts as the main switches. During dummy load and magnet testing, the test result showed that the power supply could meet the specification. This article will describe some detail of power supply simulation, design and testing. Some test waveform and pictures are presented in this paper.
 
 
TUP254 Real Time Monitoring of the Power Limit Resistor in the Boost Injection Kicker Power Supply 1301
 
  • J.-L. Mi, J. Sandberg, Y. Tan, W. Zhang
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
After years of suffering Booster Injection Kicker transistor bank driver regulator trouble shooting, a new real time monitor system has been developed. A simple and floating circuit has been designed and tested. This circuit monitor system can real time monitor the driver regulator power limit resistor status and warn machine operators if the power limit resistor changes values. This paper will introduce the power supply mainly and the new designed monitoring system.
 
 
TUP255 Solid-State Transmitter for a 2 MW Klystron 1304
 
  • M.K. Kempkes, M.P.J. Gaudreau, T.H. Hawkey, K. Schrock
    Diversified Technologies, Inc., Bedford, Massachusetts, USA
 
  Diversified Technologies, Inc. delivered a transmitter for a 2 MW, 500 MHz klystron manufactured by Communications and Power Industries, Inc. The transmitter design eliminates the need for a large pulse transformer; eliminates the crowbar for greater system availability and klystron reliability, and provides full control and monitoring of critical transmitter functions, settings, and fault diagnostics. The klystron beam power is generated by two high voltage power supplies, each capable of producing 150 kW CW power at 100 kV, with ~0.1% regulation. The transmitter can operate at lower average power in the unlikely event a single power supply goes off-line. The main solid-state switch, a series stack of commercially available IGBTs, delivers a range of HV pulsewidths to the klystron under normal operating conditions, and protects the klystron against arc damage. Should the current in the switch exceed a preset fault threshold value, the switch opens in ~ 1 μs to disconnect the high voltage from the klystron. In this paper, DTI will describe the architecture of the 2 MW klystron transmitter and its present status.  
 
TUP256 Affordable, Short Pulse Marx Modulator 1307
 
  • M.K. Kempkes, J.A. Casey, M.P.J. Gaudreau, R.A. Phillips
    Diversified Technologies, Inc., Bedford, Massachusetts, USA
  • J. Casey
    Rockfield Research, Inc. east, Winchester, Massachusetts, USA
 
  Funding: U.S. Department of Energy
Under a U.S. Department of Energy grant, Diversified Technologies, Inc. (DTI) is developing a short pulse, solid-state Marx modulator. The modulator is designed for high efficiency in the 100 kV to 500 kV range, for currents up to 500 A, pulse lengths of 0.2 to 5.0 μs, and risetimes <300 ns. Key objectives of the development effort are modularity and scalablity, combined with low cost, and ease of manufacture. For short-pulse modulators, this Marx topology provides a means to achieve fast risetimes and flattop control that are simply not available with hard switch or transformer-coupled topologies. In this paper, DTI will describe the new design and provide an update on progress.
 
 
TUP259 A Solid-State Nanosecond Beam Kicker Modulator Based on the DSRD Switch 1310
 
  • A.L. Benwell, R. Akre, C. Burkhart, A. Krasnykh, T. Tang
    SLAC, Menlo Park, California, USA
  • A. Kardo-Sysoev
    IOFFE, St. Petersburg, Russia
 
  Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515
A fast solid-state beam kicker modulator is under development at the SLAC National Accelerator Laboratory. The program goal is to develop a modulator that will deliver 4 ns, ±5 kV pulses to the ATF2 damping ring beam extraction kicker. The kicker is a 50 Ω, bipolar strip line, 60 cm long, fed at the downstream end and terminated at the upstream end. The bunch spacing in the ring is 5.6 ns, bunches are removed from the back end of the train, and there is a gap of 103.6 ns before the next train. The modulator design is based on an opening switch topology that uses Drift Step Recovery Diodes as the opening switches. The design and results of the modulator development are discussed.
 
 
TUP261 The ILC P2 Marx and Application of the Marx Topology to Future Accelerators 1313
 
  • M.A. Kemp, A.L. Benwell, C. Burkhart, J. Hugyik, R.S. Larsen, D.J. MacNair, K.J.P. Macken, M.N. Nguyen, J.J. Olsen
    SLAC, Menlo Park, California, USA
 
  Funding: Work supported by the US Department of Energy under contract DE-AC02-76SF00515.
The SLAC P2 Marx is under development for the ILC linac klystron modulator. Specifications are for an output of 120 kV, 140 A, 1.6 ms pulse width, 5 Hz pulse repetition frequency, and ± 0.5% flat-top. The SLAC P2 Marx builds upon the success of the P1 Marx, which is currently undergoing lifetime evaluation. While the P2 Marx’s target application is the ILC, characteristics of the Marx topology make it equally well-suited for different parameter ranges; for example, increased pulse repetition frequency, increased output current, longer pulse width, etc. Marx parameters such as the number of cells, cell capacitance, and component selection can be optimized for the application. This paper provides an overview of the P2 Marx development including design, fabrication progress, and test results for the modulator and sub-assemblies. High-availability features of the modulator such as the diagnostic/prognostic embedded control system and fault-adaptive automatic reconfiguration will be detailed. In addition, the scalability of the Marx topology to other long-pulse parameter ranges will be highlighted. Topology adaptations for several proposed accelerators will be presented.
 
 
TUP265 A Solenoid Capture System for a Muon Collider 1316
 
  • H.G. Kirk, R.C. Fernow, N. Souchlas
    BNL, Upton, Long Island, New York, USA
  • J.J. Back
    University of Warwick, Coventry, United Kingdom
  • C.J. Densham, P. Loveridge
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  • X.P. Ding
    UCLA, Los Angeles, California, USA
  • V.B. Graves
    ORNL, Oak Ridge, Tennessee, USA
  • T. Guo, F. Ladeinde, V. Samulyak, Y. Zhan
    SUNY SB, Stony Brok, New York, USA
  • K.T. McDonald
    PU, Princeton, New Jersey, USA
  • R.J. Weggel
    Particle Beam Lasers, Inc., Northridge, California, USA
 
  Funding: This work was supported in part by the US DOE Contract No. DE-AC02-98CH10886.
The concept for a muon-production system for a muon collider or neutrino factory calls for an intense 4-MW-class proton beam impinging upon a free-flowing mercury jet immersed in a 20-T solenoid field. This system is challenging in many aspects, including magnetohydrodynamics of the mercury jet subject to disruption by the proton beam, strong intermagnetic forces, and the intense thermal loads and substantial radiation damage to the magnet coils due to secondary particles from the target. Studies of these issues are ongoing, with a sketch of their present status given here.
 
 
TUP267 LANSCE Drift Tube Linac Water Control System Refurbishment 1319
 
  • P.S. Marroquin, J.D. Bernardin, J.G. Gioia, J.A. Ortiz
    LANL, Los Alamos, New Mexico, USA
 
  Funding: Funding Agency: Work performed under the auspices of the U.S. Department of Energy, under contract DE-AC52-06NA25396.
There are several refurbishment projects underway at the Los Alamos National Laboratory LANSCE linear accelerator. Systems involved are: RF, water cooling, networks, diagnostics, timing, controls, etc. The Drift Tube Linac (DTL) portion of the accelerator consists of four DTL tanks, each with three independent water control systems. The systems are about 40 years old, use outdated and non-replaceable equipment and NIM bin control modules, are beyond their design life and provide unstable temperature control. Insufficient instrumentation and documentation further complicate efforts at maintaining system performance. Detailed design of the replacement cooling systems is currently in progress. Previous design experience on the SNS accelerator water cooling systems will be leveraged. Plans call for replacement of water piping, manifolds, pumps, valves, mix tanks, instrumentation (flow, pressure and temperature) and control system hardware and software. This presentation will focus on the control system design with specific attention on planned use of the National Instruments Compact RIO platform with the Experimental Physics and Industrial Control System (EPICS) software toolkit.
 
 
TUP269 Design and Analysis of SRF Cavities for Pressure Vessel Code Compliance 1322
 
  • C.M. Astefanous, J.P. Deacutis, D. Holmes, T. Schultheiss
    AES, Medford, NY, USA
  • I. Ben-Zvi
    Stony Brook University, Stony Brook, USA
  • W. Xu
    BNL, Upton, Long Island, New York, USA
 
  Funding: This work was funded by Stony Brook University under contract number 52702.
Advanced Energy Systems, Inc. is under contract to Stony Brook University to design and build a 704 MHz, high current, Superconducting RF (SRF) five cell cavity to be tested at Brookhaven National Laboratory. This cavity is being designed to the requirements of the SPL at CERN while also considering operation with electrons for a potential RHIC upgrade at Brookhaven. The β=1 cavity shape, developed by Brookhaven, is designed to accelerate 40 mA of protons at an accelerating field of 25 MV/m with a Q0 > 8·109 at 2K while providing excellent HOM damping for potential electron applications. 10-CFR-851 states that all pressurized vessels on DOE sites must conform to applicable national consensus codes or, if they do not apply, provide an equivalent level of safety and protection. This paper presents how the 2007 ASME Boiler and Pressure Vessel Code Section VIII, Division 2 requirements can be used to satisfy the DOE pressure safety requirements for a non-code specified material (niobium) pressure vessel.
 
 
TUP270 RF and Structural Analysis of the 72.75 MHz QWR for the ATLAS Upgrade 1325
 
  • T. Schultheiss, J. Rathke
    AES, Medford, NY, USA
  • J.D. Fuerst, M.P. Kelly, P.N. Ostroumov
    ANL, Argonne, USA
 
  Funding: This work was supported by Argonne National Lab under contract # 0F-32381 & 0F32422
An energy upgrade to the heavy-ion accelerator ATLAS at Argonne Lab is progressing*,**. The plans include replacing split-ring cavities with high performance quarter wave resonators. The new 72.75 MHz resonators are designed for optimum ion velocity β=.077 and a record high accelerating voltage of 2.5 MV by modifying the top geometry and reducing the peak surface fields. This new cavity has a longer center conductor than the 109 MHz cavities previously built by ANL with AES assistance, this and the other geometry changes add new engineering requirements to the design. This paper presents the engineering studies that were performed to resolve new issues. These studies include determining structural frequencies of the center conductor and stiffening methods, resonator frequency sensitivity to helium pressure fluctuations, and determining stress levels due to pressure and slow tuning. Evaluation of fast piezoelectric tuner frequency shift to tuner load was also performed and the local cavity shape was optimized based on these results.
* P.N. Ostroumov, et.al, “A New Atlas Efficiency and Intensity Upgrade Project,” SRF2009, tuppo016
** P.N. Ostroumov, et.al., “Efficiency and Intensity Upgrade of the Atlas Facility,” LINAC 2010, MOP045
 
 
TUP271 CESR-type SRF Cavity - Meeting the ASME Pressure Vessel Criteria by Analysis 1328
 
  • T. Schultheiss, J. Rathke
    AES, Medford, NY, USA
  • V. Ravindranath, J. Rose, S.K. Sharma
    BNL, Upton, Long Island, New York, USA
 
  Funding: This work is supported by BNL under contract #147322
Over a dozen CESR-B Type SRF cryomodules have been implemented in advanced accelerators around the world. The cryomodule incorporates a niobium cavity operating in liquid helium at approximately 1.2 bar and at 4.5 K, and therefore, is subjected to a differential pressure of 1.2 bar to the beam vacuum. Over the past few decades niobium RRR values have increased, as manufacturing processes have improved, resulting in higher purity niobium and improved thermal properties. Along with these increases may come a decrease of yield strength, therefore, prior designs such as CESR-B, must be evaluated at the newer strength levels when using the newer high purity niobium. In addition to this the DOE directive 10CFR851 requires all DOE laboratories to provide a level of safety equivalent to that of the ASME Boiler and Pressure Vessel codes. The goal of this work was to analyze the CESR-B Type cavity and compare the results to ASME pressure vessel criteria and where necessary modify the design to meet the code criteria.
 
 
TUP272 Analysis and Comparison to Test of AlMg3 Seals Near a SRF Cavity 1331
 
  • T. Schultheiss, C.M. Astefanous, M.D. Cole, D. Holmes, J. Rathke
    AES, Medford, NY, USA
  • I. Ben-Zvi, D. Kayran, G.T. McIntyre, B. Sheehy, R. Than
    BNL, Upton, Long Island, New York, USA
  • A. Burrill
    JLAB, Newport News, Virginia, USA
 
  The Energy Recovery Linac (ERL) presently under construction at Brookhaven National Laboratory is being developed as research and development towards eRHIC, an Electron-Heavy Ion Collider. The experimental 5-cell 703.75 MHz (ECX) cavity was recently evaluated at continuous field levels greater than 10 MV/m. These tests indicated stored energy limits of the cavity on the order of 75 joules. During design of the cavity the cold flange on one side was moved closer to the cavity to allow the cavity to fit into the available chemical processing chamber at Jefferson Laboratory. RF and thermal analysis of the AlMg3 seal region of the closer side indicate this to be the prime candidate limiting the fields. This work presents the analysis results and compares these results to test data.  
 
TUP273 RF Thermal and Structural Analysis of the 60.625 MHz RFQ for the ATLAS Upgrade 1334
 
  • T. Schultheiss, J. Rathke
    AES, Medford, NY, USA
  • A. Barcikowski, P.N. Ostroumov
    ANL, Argonne, USA
  • D.L. Schrage
    TechSource, Santa Fe, New Mexico, USA
 
  Funding: This work was supported by Argonne National Lab under contract # 0F-32402
The upgrade for the ATLAS facility is designed to increase the efficiency and intensity of beams for the user facility*, **. This will be accomplished with a new CW normal conducting RFQ, which will increase both transverse and longitudinal acceptance of the LINAC. This RFQ must operate over a wide range of power levels to accelerate ion species from protons to uranium. The RFQ design is a split coaxial structure and is made of OFE copper. The geometry of the design must be stable during operation. Engineering studies of the design at different RF power levels were conducted to ensure that the geometry requirements were met. Frequency shift analysis was also completed to determine the effects of high power levels. Thermal stress analysis was completed to show that the structure frequency is repeatable.
*P.N. Ostroumov, et.al, “A New Atlas Efficiency and Intensity Upgrade Project,” SRF2009, tuppo016
**P.N. Ostroumov, et.al., “Efficiency and Intensity Upgrade of the Atlas Facility,” LINAC 2010, MOP045
 
 
TUP274 Oak Ridge National Laboratory Spallation Neutron Source Electrical Systems Availability and Improvements 1337
 
  • R.I. Cutler, D.E. Anderson, W.E. Barnett, J.D. Hicks, J.J. Mize, J. Moss, K. Norris, V.V. Peplov, K.R. Rust, J. T. Weaver
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
SNS electrical systems have been operational for 4 years. System availability statistics and improvements are presented for ac electrical systems, dc and pulsed power supplies and klystron modulators
 
 
TUP275 SNS Linac Modulator Operational History and Performance 1340
 
  • V.V. Peplov, D.E. Anderson, R.I. Cutler, M. Wezensky
    ORNL, Oak Ridge, Tennessee, USA
  • J.D. Hicks, R.B. Saethre
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Fourteen High Voltage Converter Modulators (HVCM) were initially installed at the Spallation Neutron Source Linear Accelerator (SNS Linac) at the Oak Ridge National Laboratory in 2005. A fifteenth HVCM was added in 2009. Each modulator provides a pulse of up to 140 kV at a maximum width of 1.35 msec. Peak power level is 11 MW with an 8% duty factor. The HVCM system must be available for neutron production (NP) 24/7 with the exception being two, 6-week maintenance periods per year. HVCM reliability is one of the most important factors to maximize Linac availability and achieve SNS performance goals. During the last few years several modifications have been implemented to improve the overall system reliability. This paper presents operational history of the HVCM systems and examines failure mode statistical data since the modulators began operating at 60 Hz. System enhancements and upgrades aimed at providing long term reliable operation with minimal down time are also discussed in the paper.  
 
TUP276 Measurement of Thermal Dependencies of PBG Fiber Properties 1343
 
  • R. Laouar, E.R. Colby, R.J. England, R.J. Noble
    SLAC, Menlo Park, California, USA
 
  Funding: Department Of Energy
Photonic crystal fibers (PCFs) represent a class of optical fibers which have a wide spectrum of applications in the telecom and sensing industries. Currently, the Advanced Accelerator Research Department at SLAC is developing photonic bandgap particle accelerators, which are photonic crystal structures with a central defect used to accelerate electrons and achieve high longitudinal electric fields. Extremely compact and less costly than the traditional accelerators, these structures can support higher accelerating gradients and will open a new era in high energy physics as well as other fields of science. Based on direct laser acceleration in dielectric materials, the so called photonic band gap accelerators will benefit from mature laser and semiconductor industries.
 
 
TUP277 RF Design of the Power Coupler for the Spiral2 Single Bunch Selector 1346
 
  • F. Consoli, A.C. Caruso, G. Gallo, D. Rifuggiato, E. Zappalà
    INFN/LNS, Catania, Italy
  • M. Di Giacomo
    GANIL, Caen, France
 
  Funding: Work supported by the European Community FP7 – Capacities – SPIRAL2 Preparatory Phase n° 212692.
The single bunch selector of the Spiral2 driver uses high impedance travelling wave electrodes driven by fast pulse generators. The characteristic impedance of 100 Ω has been chosen to reduce the total power, but this non standard value requires the development of custom feed-through and transitions to connect the pulse generators and the matching load to the electrodes. The paper reviews the design of these devices.
 
 
TUP278 Tuning Method for the 2π/3 Traveling Wave Structures 1349
 
  • A.S. Setty
    THALES, Colombes, France
 
  To build a constant gradient traveling wave structure, one must perform cold tests under a press in order to tune the different cells individually. For the tests to be valid, the test cells must be terminated by shorting planes located in planes of symmetry in which the electric field vector is normal in such a way that the standing wave "trapped" between them is an exact representation of the instantaneous traveling wave one wishes to study. For the TW structure, the cavities are put three by three under the press. We then try to reduce the contribution of "mixed cells" by adding to one wavelength at 2π/3 mode two-quarter wavelengths. This is possible when the end-cells mode at the same frequency is π/2 instead of 2π/3. These end cells are not included in the final assembly. The setting process will be analysed.  
 
TUP279 A CW RFQ Prototype 1352
 
  • U. Bartz, A. Schempp
    IAP, Frankfurt am Main, Germany
 
  A short RFQ prototype was built for tests of high power RFQ structures. We will study thermal effects and determine critical points of the design. HF-simulations with CST Microwave Studio and measurements were done. The RF-tests with continues power of 20 kW/m and simulations of thermal effects with ALGOR were finished successfully. Optimization of some details of the facility are on focus now. First results and the status of the project will be presented.  
 
TUP282 The MICE Target 1355
 
  • P.J. Smith, C.N. Booth, P. Hodgson, E. Overton, M. Robinson
    Sheffield University, Sheffield, United Kingdom
  • G.J. Barber, K.R. Long
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • E.G. Capocci, J.S. Tarrant
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  • B.J.A. Shepherd
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
 
  The MICE experiment uses a beam of low energy muons to test the feasibility of ionization cooling. This beam is derived parasitically from the ISIS accelerator at the Rutherford Appleton Laboratory. A target mechanism has been developed and deployed that rapidly inserts a small titanium target into the circulating proton beam immediately prior to extraction without undue disturbance of the primary ISIS beam. The first target drive was installed in ISIS during 2008 and operated successfully for over 100,000 pulses. A second upgraded design was installed in 2009 and after more than half a million actuations is still in operation. Further upgrades to the target design are now being tried in a separate test rig at the Rutherford Appleton Laboratory. The technical specifications for these upgraded designs are given and the motivations for the improvements are discussed. Additionally, further future improvements to the current design are discussed.  
 
TUP283 Inductively Coupled, Compact HOM Damper for the Advanced Photon Source 1358
 
  • G.J. Waldschmidt, D. Horan, L.H. Morrison
    ANL, Argonne, USA
 
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
The Advanced Photon Source requires damping of higher-order modes in the storage ring rf cavities in order to prevent beam instability at beam currents in excess of 100 mA proposed for the APS Upgrade. Due to constraints imposed by available space and by existing 35-mm pick-up ports on the cavity, a compact design has been analyzed with a quarter-wave rejection filter of the fundamental mode. Separate broadband, low-frequency and high-frequency dampers are utilized to span the frequency range from 500 MHz to 1500 MHz. The dampers have been designed to reject the fundamental cavity mode, couple strongly to HOM’s, utilize an external rf load, minimize the overall size, and incorporate rf diagnostics. In addition, the mechanical design has been optimized to simplify construction, improve mechanical stability, and reduce thermally induced stresses.
 
 
TUP284 AGS Tune Jump System to Cross Horizontal Depolarization Resonances Overview 1361
 
  • J.W. Glenn, L. A. Ahrens, Z. Altinbas, W. Fu, J.-L. Mi, P.J. Rosas, V. Schoefer, C. Theisen
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Two partial snakes overcome the vertical depolarizing resonances in the AGS. But a new type of depolarizing intrinsic resonance from horizontal motion appeared. We reduce these using horizontal tune jumps timed to these resonances. We gain a factor of five in crossing rate with a tune jump of 0.04 in 100 micro-sec. Two quadrapoles, we described in 2009 *, pulse 42 times, the current matching beam energy. The power supplies for these quads will be described in this conference**. The controls for the Jump Quad system is based on a BNL designed Quad Function Generator. Two modules are used; one for timing, and one to supply reference voltages. Synchronization is provided by a proprietary serial bus, the Event Link. The AgsTuneJump application predicts the times of the resonances during the AGS cycle and calculates the power supply trigger times from externally collected tune and energy verses time data and the Low and High PS voltage functions from a voltage to current model of the power supply. The system was commissioned during runs 09 & 10. Beam effects are described elsewhere in this conference***. Details of improvements, operation and the feed forward software will be described.
* JW Glenn, et al “AGS Fast Spin Resonance,-” PAC-09
** JL Mi, et al “AGS Tune Jump Power-” these proceedings
*** L.A.Ahrens, et al "Recent RHIC Motivated Polarized-" these proceedings
 
 
TUP286 Development and Testing of Carbon Fiber Vacuum Chamber Supports for NSLS-II 1364
 
  • B.N. Kosciuk, C. Hetzel, J.A. Kierstead, V. Ravindranath, S.K. Sharma, O. Singh
    BNL, Upton, Long Island, New York, USA
 
  The NSLS-II Synchrotron Light Source, a 3 GeV electron storage ring currently under construction at Brookhaven National Laboratory is expected to provide exceptional orbit stability in order to fully utilize the very small emittance of the electron beam. In order to realize this, the beam position monitor (BPM) pick up electrodes which are part of the orbit feedback system must have a high degree of mechanical and thermal stability. In the baseline design, this would be accomplished by using flexible invar plates to support the multi-pole vacuum chamber at the positions where the BPM pick up electrodes are mounted. However, it was later discovered that the close proximity of the invar supports to the adjacent focusing magnets had an adverse affect on the magnetic fields. To mitigate this issue, we propose the use of carbon fiber composite in place of invar as a low CTE (coefficient of thermal expansion) material. Here we show the design, development and testing of thermally stable composite supports capable of sub-micron thermal stability.  
 
TUP288 A Very Thin Havar Film Vacuum Window for Heavy Ions to Perform Radiobiology Studies at the BNL Tandem 1367
 
  • P. Thieberger, H. Abendroth, J.G. Alessi, L. Cannizzo, C. Carlson, A. Gustavsson, M.G. Minty, L. Snydstrup
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Heavy ion beams from one of the BNL Tandem Van de Graaff accelerators will be made available for radiobiology studies on cell cultures. Energy losses need to be minimized both in the vacuum window and in the air in order to achieve the ranges required for the cells to be studied. This is particularly challenging for ions heavier than iron. The design is presented of a 0.4” diameter Havar film window that will satisfy these requirements. Films as thin as 80μinches were successfully pressure tested. The final thickness to be used may be slightly larger to help in achieving pin hole free windows. We discuss design considerations and present pressure and vacuum test results as well as tests with heavy ion beams.
 
 
TUP290 Progress on MICE RFCC Module for the MICE Experiment 1370
 
  • A.J. DeMello, N. Andresen, M.A. Green, D. Li, S.P. Virostek, M.S. Zisman
    LBNL, Berkeley, California, USA
  • Y. Cao, S. Sun, L. Wang, L. Yin
    SINAP, Shanghai, People's Republic of China
  • A.B. Chen, X.K. Liu, H. Pan, F.Y. Xu
    ICST, Harbin, People's Republic of China
  • M. Reep, D.J. Summers
    UMiss, University, Mississippi, USA
 
  Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
We describe the recent progress on the design and fabrication of the RFCC (RF and Coupling Coil) module for the international Muon Ionization Cooling Experiment (MICE). The MICE cooling channel has two RFCC modules; each has four 201-MHz normal conducting RF cavities and one superconducting solenoid magnet. The magnet is designed to be cooled by three cryocoolers. Fabrication of the RF cavities is complete; design and fabrication of the magnets are in progress. The first magnet is expected to be finished by the end of 2011.
 
 
TUP293 ESTB: A New Beam Test Facility at SLAC 1373
 
  • M.T.F. Pivi, H. Fieguth, C. Hast, R.H. Iverson, J. Jaros, R.K. Jobe, L. Keller, D.R. Walz, S.P. Weathersby, M. Woods
    SLAC, Menlo Park, California, USA
 
  End Station Test Beam (ESTB) is an end beam line at SLAC using a small fraction of the 13.6 GeV electron beam from the Linac Coherent Light Source (LCLS), restoring test beam capabilities in the large End Station A (ESA) experimental hall. In the past, 18 institutions participated in the ESA program at SLAC. The ESTB program will provide one of a kind test beams essential for developing accelerator instrumentation and accelerator R&D, performing particle and astroparticle physics detector research, linear collider machine and detector interface (MDI) R&D, developing of radiation-hard detectors and material damage studies with several distinctive features. At this stage, 4 new kicker magnets are added to divert 5 Hz of LCLS beam to the A-line, a new beam dump is installed and a new PPS system is built in ESA. In a second stage, a secondary hadron target will be installed, able to produce pions up to about 12 GeV/c at 1 particle/pulse. In summary, ESTB provides a new test facility for LHC detector upgrades, Super B Factory detector development, and Linear Collider accelerator and detector R&D with the first beam expected by June and users starting operations by July 2011.