Keyword: factory
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MOPPC018 Single/Few Bunch Space Charge Effects at 8 GeV in the Fermilab Main Injector space-charge, background, simulation, proton 163
 
  • D.J. Scott, D. Capista, I. Kourbanis, K. Seiya, M.-J. Yang
    Fermilab, Batavia, USA
  
  For Project X, it is planned to inject a beam of 3 1011 particles per bunch into the Main Injector. Therefore, at 8 GeV, there will be increased space charge tune shifts and an increased incoherent tune spread. In preparation for these higher intensity bunches exploratory studies have commenced looking at the transmission of different intensity bunches at different tunes. An experiment is described with results for bunch intensities between 20 and 172 109 particles. To achieve the highest intensity bunches coalescing at 8 GeV is required, resulting in a longer bunch length. Comparisons show that similar transmission curves are obtained when the intensity and bunch length have increased by factors of 3.2 and 3.4 respectively, indicating the incoherent tune shifts are similar, as expected from theory. The results of these experiments will be used in conjugation with simulations to further study high intensity bunches in the Main Injector.  
 
MOPPC041 Control of Beam Losses in the Front End for the Neutrino Factory proton, target, solenoid, collider 223
 
  • C.T. Rogers
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • D.V. Neuffer
    Fermilab, Batavia, USA
  • P. Snopok
    IIT, Chicago, Illinois, USA
  
  The Neutrino Factory produces neutrinos by muon decay in a storage ring. Pions are produced by firing high energy protons onto a target. Pions decay to muons, which are captured and accelerated to high energy. The target produces additionally a large background that is deposited in the muon capture front end and subsequent components. The implications of energy deposition in the front end lattice for the Neutrino Factory are addressed. Several approaches to mitigating the effect are proposed and discussed, including proton absorbers, chicane, and shielding.  
 
MOPPC042 Higgs Boson Muon Collider Factory: h0, A, H Studies collider, solenoid, simulation, dipole 226
 
  • D.B. Cline, X.P. Ding, J.L. Lederman
    UCLA, Los Angeles, California, USA
  
  With the recent hints of the Higgs boson from the LHC and a mass near 125 GeV/c we re-propose to study and build a muon collider Higgs factory to study the Higgs in the S channel. This was first proposed in 1992 by the first author. It is essential to study the Higgs boson for clues to new physics. The formation of the DOE MAP program, recent advances in 6D μ cooling methods, simulation, and targeting make this a feasible project to initiate at this time. This collider would fit into the FNAL site.  
 
MOPPC044 Gallium as a Possible Target Material for a Muon Collider or Neutrino Factory target, proton, collider, interaction-region 232
 
  • X.P. Ding
    UCLA, Los Angeles, California, USA
  • J.S. Berg, H.G. Kirk, H. K. Sayed
    BNL, Upton, Long Island, New York, USA
  • V.B. Graves
    ORNL, Oak Ridge, Tennessee, USA
  • K.T. McDonald
    PU, Princeton, New Jersey, USA
  • N. Souchlas, R.J. Weggel
    Particle Beam Lasers, Inc., Northridge, California, USA
  
  Funding: Work support by the U.S. Department of Energy in part under Awards No. DE-AC02-98CH10886 (BNL) and No. DF-FG02-92ER40695 (UCLA)
We consider the potential for a free-gallium-jet as an option for the pion-production target at a Muon Collider or Neutrino Factory. Advantages of such a target choice are its liquid state at relatively low temperature, its relatively efficient meson production, and its lower activation (compared to mercury). Using the MARS15 code, we have simulated particle production initiated by incoming protons with kinetic energies (KE) between 2 and 16~GeV. For each proton beam energy, we optimized the geometric parameters of the target: the radius of the liquid jet, the incoming proton beam angle, and the crossing angle between the jet and the proton beam. We compare the quantity of generated muons using a Ga target to that from a mercury jet target. 		 
 
MOPPC049 Status of the Non-scaling Fixed Field Alternating Gradient Ring Design for the International Design Study of the Neutrino Factory acceleration, septum, lattice, electron 241
 
  • J.S. Berg, H. Witte
    BNL, Upton, Long Island, New York, USA
  • M. Aslaninejad, J. Pasternak
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • N. Bliss, A.J. Moss
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • D.J. Kelliher, S. Machida
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • S.M. Pattalwar
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The International Design Study of the Neutrino Factory is working towards delivering the optimized design of the neutrino factory facility to be presented in the Reference Design Report (RDR) in 2013. In the current baseline design a linear non-scaling fixed field alternating gradient accelerator (FFAG) was chosen as an efficient solution for the final muon acceleration. We describe updates to the design since our previous report*. We report on beam dynamics studies on the lattice. We describe recent work on the engineering for the lattice, and the results of a recent first pass at a cost estimate for the machine. Finally, we describe how an FFAG may be applicable to a lower energy neutrino factory in light of recent experimental results regarding the value of the theta(13) neutrino mixing angle**.
* J. S. Berg et al., in Proceedings of IPAC2011, San Sebastian, Spain, 832.
** F. P. An et al., Phys. Rev. Lett. 108, 171803 (2012); J. K. Ahn et al., arXiv:1204.0626v2 [hep-ex] (2012).
 		 
 
MOPPC050 The International Design Study for the Neutrino Factory lattice, target, proton, acceleration 244
 
  • K.R. Long, J.K. Pozimski
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • J.S. Berg
    BNL, Upton, Long Island, New York, USA
  
  A neutrino factory is a facility for producing a large neutrino flux from the decay of high energy muons. The International Design Study for the Neutrino Factory (IDS-NF) aims to produce a reference design report for such a facility. The report will contain the physics motivation for the facility, describe the accelerator and detector, and estimate the cost for the facility. We will briefly discuss the physics capabilities for a neutrino factory, including how recent neutrino physics results affect our understanding of a neutrino factory's performance and advantages. We will give an overview of our baseline design for the accelerator facility. We will then outline the most significant areas of progress in our studies of the accelerator subsystems.
Paper submitted on behalf of the International Design Study for the Neutrino Factory collaboration. 		 
 
MOPPC062 Eigenmode Computation for Cavities with Perturbed Geometry Based on a Series Expansion of Unperturbed Eigenmodes cavity, HOM, wakefield, higher-order-mode 277
 
  • K. Brackebusch, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
  
  Funding: Work supported by Federal Ministry for Research and Education BMBF under contracts 05H09HR5 and 05K10HRC.
The geometry of an accelerator cavity determines its eigenmodes and thereby its performance characteristics. Therefore, accelerating performance and wakefield characteristics may be improved by an intentional modification of the geometry. However, undesired geometry perturbations due to manufacturing tolerances and operational demands can likewise impair it. To analyze the effects of geometry variations on the eigenmodes, parameter studies are to be undertaken. Using common eigenmode solvers it usually is necessary to perform a full eigenmode computation for each variation step, even if the geometry is only slightly altered. Parameter studies for cavity perturbations thus tend to be computationally extensive and inefficient. In this paper, we present the fundamentals of an efficient eigenmode computation method for varying cavity geometries. Knowing a set of initial eigenmodes of an unperturbed geometry, the method allows expanding the eigenmodes of any geometry that is part of the unperturbed one as a series of the initial eigenmodes. Thereby the computation effort may be significantly reduced. The method is demonstrated by means of analytically evaluable cavity geometries. 		 
 
MOPPD044 Optimization of the Target Subsystem for the New g-2 Experiment target, proton, simulation, focusing 460
 
  • C. Y. Yoshikawa, C.M. Ankenbrandt
    Muons, Inc, Batavia, USA
  • A.F. Leveling, N.V. Mokhov, J.P. Morgan, D.V. Neuffer, S.I. Striganov
    Fermilab, Batavia, USA
  
  A precision measurement of the muon anomalous magnetic moment, aμ = (g-2)/2, was previously performed at BNL with a result of 2.2 - 2.7 standard deviations above the Standard Model (SM) theoretical calculations. The same experimental apparatus is being planned to run in the new Muon Campus at Fermilab, where the muon beam is expected to have less pion contamination and the extended dataset may provide a possible 7.5σ deviation from the SM, creating a sensitive and complementary benchmark for proposed SM extensions. We report here on a preliminary study of the target subsystem where the apparatus is optimized for pions that have favorable phase space to create polarized daughter muons around the magic momentum of 3.094 GeV/c, which is needed by the downstream g 2 muon ring.  
 
MOPPR035 Study of the Signal Processing System for a Cavity Beam Position MonitorS cavity, FEL, electron, simulation 855
 
  • B.P. Wang, Y.B. Leng, L.Y. Yu, W.M. Zhou
    SINAP, Shanghai, People's Republic of China
  • Z.C. Chen, R.X. Yuan, N. Zhang
    SSRF, Shanghai, People's Republic of China
  
  A cavity beam position monitor (CBPM), which can realize nanometer-level resolution as reported, is important and indispensable for a free electron laser (FEL) facility. A prototype of CBPM, with resonant frequency of 5712 MHz, has been installed in the Shanghai deep ultraviolet free-electron laser source (SDUV-FEL) facility. A plug & play CBPM signal processor based on a broadband oscilloscope embedded IOC and FFT technology has been developed to do quick evaluation of prototype. According to the evaluation results, a series of simulation using Monte Carlo simulation method, has been carried as a guideline for the design of dedicated CBPM signal processing system. The development progress of signal processing system will be introduced as well.  
 
MOPPR057 Development of a Cavity Beam Position Monitor for CLIC cavity, dipole, linac, coupling 915
 
  • F.J. Cullinan, S.T. Boogert, N.Y. Joshi, A. Lyapin
    JAI, Egham, Surrey, United Kingdom
  • E. Calvo, N. Chritin, F. Guillot-Vignot, T. Lefèvre, L. Søby
    CERN, Geneva, Switzerland
  • A. Lunin, M. Wendt, V.P. Yakovlev
    Fermilab, Batavia, USA
  • S.R. Smith
    SLAC, Menlo Park, California, USA
  
  The Compact Linear Collider (CLIC) project presents many challenges to its subsystems and the beam diagnostics in particular must perform beyond current limitations. The requirements for the CLIC main beam position monitors foresee a spacial resolution of 50 nm while delivering a 10 ns temporal resolution within the bunch train. We discuss the design of the microwave cavity pick-up and associated electronics, bench top tests with the first prototype cavity, as well as some of the machine-specific integration and operational issues.  
 
MOPPR073 Analysis of Resonant TE Wave Modulation Signals for Electron Cloud Measurements electron, resonance, coupling, cavity 957
 
  • S. De Santis
    LBNL, Berkeley, California, USA
  • D. Alesini
    INFN/LNF, Frascati (Roma), Italy
  • J.P. Sikora
    CLASSE, Ithaca, New York, USA
  
  Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy under Contracts DE-FC02-08ER41538, DE-AC02-05CH11231.
Recent TE wave measurements of the electron cloud density in the beampipe at CesrTA and DAΦNE have shown that, especially near cutoff, the microwave excitation takes place by coupling to a standing wave, rather than to a propagating TE mode. With the beampipe acting as a resonant cavity, the effect of the periodic electron cloud density is a modulation of the cavity's resonant frequency. As a result, the measured sidebands are a combination of amplitude, phase, and frequency modulation, as the periodic cloud density modulates this resonant frequency. The quality factor Q of the resonance will determine its response to transients in the electron cloud density, and the resulting effect on modulation sidebands. In order to estimate the peak electron cloud density and its spacial distribution, knowledge of the Q and the standing wave pattern need to be determined, either by experimental measurements or simulation codes. In this paper we analyze the dependence of the modulation sidebands on the electron cloud density in two different regimes, when the cloud rise/decay time is much longer, or much shorter than the filling time of the resonance. 		 
 
TUEPPB007 A Self Consistent Multiprocessor Space Charge Algorithm that is Almost Embarrassingly Parallel space-charge, simulation, collective-effects, brightness 1128
 
  • E.W. Nissen
    JLAB, Newport News, Virginia, USA
  • B. Erdelyi
    Northern Illinois University, DeKalb, Illinois, USA
  • S.L. Manikonda
    ANL, Argonne, USA
  
  Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
We present a space charge code that is self consistent, massively parallelizeable, and requires very little communication between the computer nodes; making the calculation almost embarrassingly parallel. This method is implemented in the code COSY Infinity where the differential algebras used in this code are important to the algorithm's proper functioning. The method works by calculating the self consistent charge distribution using the statistical moments of the test particles, and converting them into polynomial series coefficients. These coefficients are combined with differential algebraic integrals to form the potential, and electric fields. The result is a transfer map which contains the effects of space charge. This method allows for massive parallelization since its statistics based solver doesn’t require any binning of the particles, and only requires a vector containing the partial sums of the statistical moments for the different nodes to be passed. All other calculations are done independently. The resulting maps can be used to analyze the system using normal form analysis, as well as advance particles in numbers and at speeds that were previously impossible. 		 
 
TUPPD003 Optimisation of Cooling Lattice Based on Bucked Coils for the Neutrino Factory lattice, emittance, simulation, cavity 1407
 
  • A. Alekou, J. Pasternak
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  The ionisation cooling technique will be used at the Neutrino Factory to reduce the transverse phase space of the muon beam. For efficient cooling, high average RF gradient and strong focusing are required to be applied in the cooling channel. However, high magnetic field at the position of the RF cavities induces electric field breakdown and therefore, a novel configuration, the Bucked Coils lattice, has been proposed to mitigate this problem. The Bucked Coils lattice has significantly lower magnetic field in the RF cavities by using coils of different radius and opposite polarity. This paper presents the optimisation of this lattice, its cooling performance, together with the preliminary conceptual engineering design.  
 
TUPPD004 Costing Methodology and Status of the Neutrino Factory cryogenics, target, linac, solenoid 1410
 
  • A. Kurup
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • N. Bliss, N.A. Collomb, A.F. Grant
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  
  The International Design Study for the Neutrino Factory will produce a reference design report in 2013 that will contain a detailed performance analysis of the Neutrino Factory and a cost estimate. In order to determine the cost a number of engineering features need to be included in the accelerator physics design, which can require the physics design to be re-optimized. The cost estimate is determined in such a way as to make efficient use of the engineering resources available and to simplify the process of modifying the physics design to include engineering features. This paper will present details of the methodology used to determine the cost estimate and the current status of each subsystem.  
 
TUPPD005 Design Concept for Nu-STORM: an Initial “Very Low-Energy Neutrino Factory” injection, storage-ring, target, proton 1413
 
  • D.V. Neuffer, A.D. Bross, S. Geer, A. Liu, M. Popovic
    Fermilab, Batavia, USA
  • C.M. Ankenbrandt, T.J. Roberts
    Muons, Inc, Batavia, USA
  
  Funding: US DOE under contract DE-AC02-07CH11359
We present a design concept for a Nu-source from a STORage ring for Muons - NuSTORM. In this initial design a high-intensity proton beam produces ~5 GeV pions that provide muons that are captured using “stochastic injection” within a ~3.6 GeV racetrack storage ring. In “stochastic injection”, the ~53 GeV pion beam is transported from the target into the storage ring, dispersion-matched into a long straight section. (Circulating and injection orbits are separated by momentum.) Decays within that straight section provide muons that are within the ~2 GeV/c ring momentum acceptance and are stored for the muon lifetime of ~1000 turns. Muon (and pion) decays in the long straight sections provide neutrino beams that can be used for precision measurements of neutrino interactions, and neutrino oscillations or disappearance at L/E=~1 m/MeV. The facility is described and variations are discussed. 		 
 
TUPPD006 IDR Neutrino Factory Front End and Variations proton, target, cavity, solenoid 1416
 
  • D.V. Neuffer
    Fermilab, Batavia, USA
  • A. Alekou
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • C.T. Rogers
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • P. Snopok
    IIT, Chicago, Illinois, USA
  • C. Y. Yoshikawa
    Muons, Inc, Batavia, USA
  
  The (International Design Report) IDR neutrino factory scenario for capture, bunching, phase-energy rotation and initial cooling of muons produced from a proton source target is presented. It requires a drift section from the target, a bunching section and a phase-energy rotation section leading into the cooling channel. The rf frequency changes along the bunching and rotation transport in order to form the muons into a train of equal-energy bunches suitable for cooling and acceleration. This design is being explored within the IDR cost model. Important concerns are rf limitations and beam losses. Recent experiments on rf gradient limits suggest preferred configurations for the rf within the magnetic fields, and these considerations are incorporated into the front end design.  
 
TUPPD007 Multiple Scattering Measurements in the MICE Experiment scattering, simulation, emittance, solenoid 1419
 
  • T. Carlisle, J.H. Cobb
    JAI, Oxford, United Kingdom
  • D.V. Neuffer
    Fermilab, Batavia, USA
  
  The international Muon Ionization Cooling Experiment (MICE), under construction at RAL, will test and characterize a prototype cooling channel for a future Neutrino Factory or Muon Collider. The cooling channel aims to achieve, using liquid hydrogen absorbers, a 10% reduction in transverse emittance. The change in 4D emittance will be determined with a relative accuracy of 1% by measuring muons individually. Muon detectors include two scintillating fibre trackers embedded within 4 T solenoid fields, TOF counters and a muon ranger. Step IV of MICE will begin in 2012, producing the experiment's first precise emittance-reduction measurements. Multiple scattering in candidate Step IV absorber materials was studied in G4MICE, based on GEANT4. Equilibrium emittances for low-Z materials from hydrogen to aluminium can be studied experimentally in Step IV of MICE, and compared with simulations.  
 
TUPPD008 Recent Progress Toward a Muon Recirculating Linear Accelerator linac, dipole, cryomodule, quadrupole 1422
 
  • K.B. Beard
    Muons, Inc, Batavia, USA
  • M. Aslaninejad, C. Bonţoiu, A. Kurup, J.K. Pozimski
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • S.A. Bogacz, V.S. Morozov, Y. Roblin
    JLAB, Newport News, Virginia, USA
  
  Both Neutrino Factories (NF) and Muon Colliders (MC) require very rapid acceleration due to the short lifetime of muons. After a capture and bunching section, a linac raises the energy to about 900 MeV, and is followed by one or more Recirculating Linear Accelerators (RLA), possibly followed by a Rapid Cycling Synchrotron (RCS) or Fixed-Field Alternating Gradient (FFAG) ring. A RLA reuses the expensive RF linac section for a number of passes at the price of having to deal with different energies within the same linac. Various techniques including pulsed focusing quadrupoles, beta frequency beating, and multipass arcs have been investigated via simulations to improve the performance and reduce the cost of such RLAs.  
 
TUPPD013 Bunch Coalescing in a Helical Channel collider, acceleration, emittance, simulation 1434
 
  • C. Y. Yoshikawa, C.M. Ankenbrandt
    Muons, Inc, Batavia, USA
  • D.V. Neuffer, K. Yonehara
    Fermilab, Batavia, USA
  
  Funding: Supported in part by SBIR Grant 4725 · 09SC02739.
A high-luminosity Muon Collider requires bunch recombination for optimal luminosity. In this paper, we take advantage of the large slip factor in a helical transport channel (HTC) to coalesce bunches of muons into a single one over a shorter distance than can be achieved over a straight channel. The coalescing subsystem that is designed to merge 9 bunches has a horizontal length of ~105m and is able to achieve efficiencies of 99.7%, 98.4%, and 94.2% for 9, 11, and 13 bunches, respectively, where each bunch has emittances expected at the end of an HCC. Simplified designs incorporating fill factors for RF cavities of ~25% and ~50% obtained efficiencies of 96%, 94-95%, and 90-91% for 9, 11, and 13 bunches, respectively. The efficiencies above do not include decay losses, which would be ~8% for muons with kinetic energy of 200 MeV. 		 
 
TUPPP031 Modelling the Steady-state CSR Emission in Low Alpha Mode at the Diamond Storage Ring wakefield, electron, impedance, bunching 1677
 
  • I.P.S. Martin, C.A. Thomas
    Diamond, Oxfordshire, United Kingdom
  • R. Bartolini
    JAI, Oxford, United Kingdom
  
  The CSR emitted by short electron bunches can be of a stable or bursting nature, with transition between the two states characterised by a threshold current that depends on various machine parameters. Key to understanding this process is to develop an effective model that describes the way the electron bunch interacts with impedance sources such as the CSR wakefield and surrounding vacuum chamber. In this paper we present the latest results of modelling the equilibrium distribution calculated using the Haissinski equation driven by different impedance models. The bunch lengthening with current, bunch profiles and CSR form factors derived from this model are compared to measured data for both positive and negative momentum compaction factor. Comparisons of the measured bursting thresholds to theoretical predictions are also discussed.  
 
TUPPR024 CLIC Recombination Scheme for the Low Energy Operation Mode acceleration, luminosity, collider, linac 1864
 
  • A. Gerbershagen, D. Schulte
    CERN, Geneva, Switzerland
  • P. Burrows
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  
  The CLIC recombination scheme is a concept of multiplication of the drive beam frequency in order to generate a 12 GHz RF wave for the main beam acceleration. CLIC is designed to be operated in nominal and in low energy modes. The low energy operation modes require the train length to be increased by different factors in order to maintain the same level of luminosity. Also the number of initial trains that are merged to form each final train is changed. The combination scheme must be able to accommodate and recombine both long and short trains for nominal and low energy CLIC operation modes. The recombination hence becomes a non-trivial process and makes the correction of the errors in the drive beam more challenging. The present paper describes in detail the recombination process and its consequences.  
 
WEPPC029 Design and Development of an Octopus Thermometric System for the 704 MHz Single-cell SPL Cavity at CERN cavity, LabView, SRF, proton 2266
 
  • K.C. Liao, L. Arnaudon, O. Brunner, E. Ciapala, D.C. Glenat, W. Weingarten
    CERN, Geneva, Switzerland
  
  The octopus thermometric system is designed for the 704 MHz superconducting proton linac (SPL) cavity to detect hot spots and X-rays caused by normal conducting defects and the impact of emission electrons. This system features an octopus body and tentacle structure for good contact with the cavity and easy assembly, a multiplexing circuit with integrated microprocessor for efficient readout and a high density temperature sensor arrangement in order to complete a high resolution temperature and X-ray map. The first prototype is being manufactured and investigations are undergoing for further development.  
poster icon Poster WEPPC029 [1.715 MB]  
 
WEPPC045 Optimization of the Geometric Beta for the SSR2 Cavities of the Project X cavity, linac, cryomodule, proton 2312
 
  • P. Berrutti, M.H. Awida, I.V. Gonin, N. Solyak, A. Vostrikov, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  Project X based on the 3 GeV CW superconducting Linac and is currently in the R&D phase. The cw SC Linac starts from a low-energy SCRF section (2.1 - 165 MeV) containing three different types of resonators. HWR f=162.5 MHz (2.1 - 11 MeV) having β= 0.11, SSR1 f= 325 MHz (11 - 35 MeV) having β = 0.21. In this paper we present the analysis that lead to the final design of SSR2 f=325 MHz cavity (35 - 165 MeV). We present the results of optimization of the geometric beta and the comparison between single, double and triple spoke resonators used in Project X frontend.  
 
WEPPC054 Resonance Excitation of Longitudinal High Order Modes in Project X Linac HOM, linac, collider, kaon 2336
 
  • A.I. Sukhanov, M.H. Awida, I.V. Gonin, T.N. Khabiboulline, A. Lunin, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  Results of simulation of power loss due to excitation of longitudinal high order modes (HOMs) in the accelerating superconducting RF system of CW linac of Project X are presented. Beam structures corresponding to the various modes of Project X operation are considered: CW regime for 3 GeV physics program; pulsed mode for neutrino experiments; and pulsed regime, when Project X linac operates as a driver for Neutrino Factory/Muon Collider. Power loss and associated heat load due to resonance excitation of longitudinal HOMs are shown to be small in all modes of operation. Conclusion is made that HOM couplers can be removed from the design of superconducting RF cavities of Project X linac.  
 
WEPPC080 Minimizing Helium Pressure Sensitivity in Elliptical SRF Cavities cavity, simulation, linac, beam-loading 2396
 
  • S. Posen, M. Liepe
    CLASSE, Ithaca, New York, USA
  
  Superconducting cavities in CW operation with small beam loading can operate at high QL to significantly reduce power requirements. However, the resulting small bandwidth makes them vulnerable to microphonics from helium pressure fluctuations, which can detune the cavity and cause it to trip. In this paper, we present a mechanical optimization of elliptical cavities for minimization of df/dp, the sensitivity to helium pressure changes. Using the Cornell ERL main linac cavity as an example, an analytical model is developed to illustrate the factors that contribute to df/dp. Methods to reduce df/dp are presented. In addition, df/dp measurements made at the Cornell Horizontal Test Cryostat are presented and corrections to the model are made to account for the thickness of the welds in the helium vessel.  
 
WEPPC115 High Q0 in Superconducting Niobium Cavities: Progress at FNAL and Future Plans cavity, niobium, SRF, vacuum 2492
 
  • A. Grassellino, L.D. Cooley, C.M. Ginsburg, A. Romanenko, A.M. Rowe, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  Consistent improvement in the quality factors of SRF cavities at medium surface fields of about 70 mT represents a direct cost savings factor for the proposed Project X CW linac and other SRF accelerator projects based on CW operation. Current state-of-the-art in SRF does not provide processing recipes to maximize the Q0 at those fields since a complete understanding of the mechanisms governing the quality factor at non-negligible surface fields is not yet developed. In this contribution we present results of the FNAL effort in both scientific understanding and practical improvements and discuss the directions we are pursuing for future research.  
 
WEPPD008 Recondenser Performance: Impact on the Superconducting Undulator Magnet at Argonne National Laboratory undulator, ion, cryogenics, background 2513
 
  • J.M. Pfotenhauer, D.M. Schick
    UW-Madison/EP, Madison, Wisconsin, USA
  
  Funding: This work is supported by Argonne National Laboratory, subcontract number 9F-31982.
The current sharing temperature of 6.5 K for the superconducting undulator magnet being developed at Argonne National Laboratory drives the thermal design of the magnet’s cooling system. In order to remain below the current sharing temperature, a thermo-siphon cooling loop is being developed to sweep the anticipated heat load away from the magnet windings and deposit it in the associated liquid helium reservoir located above the magnet. Performance of the magnet’s cooling system is crucially dependent on the ability of the re-condenser to maintain the reservoir’s saturation temperature near 4 K, despite thermal stratification and slowly varying thermal profiles within the vapor region above the liquid in the reservoir. Here we report the results of an experimental investigation of the impact of various geometric configurations for the re-condenser and the thermal resistance associated with the film layer at the re-condensing surface, on the time-varying saturation temperature within the helium reservoir. The resulting temporal thermal variations in the superconducting winding are highlighted as well as the impact they have on the magnet’s stability. 		 
 
WEPPD023 Design and Manufacture of TPS BPM Diamond-Edge Gasket vacuum, synchrotron 2549
 
  • Huang, Y.T. Huang, C.-C. Chang, C.L. Chen, J.-R. Chen, G.-Y. Hsiung, H.P. Hsueh
    NSRRC, Hsinchu, Taiwan
  
  TPS vacuum chamber is oil-free machined and the material is A6061T651 which the Brinell hardness is 95 kg/mm2. Beam position monitors are installed onto the bending chambers, B1 and B2 and the straight chambers, S3 and S4. The diamond-edge gasket was chosen to seal between BPM flange (SS316L) and the vacuum chamber (A6061T651). Easily manufactured, low cost and less clamping force are three main advantages of this diamond-edge gasket. This diamond-edge gasket is made of A1050H14 which has less hardness, 32 kg/mm2 and its surface roughness is well controlled under 0.8 μm because worse surface roughness probably lead to radial leak. Considering differences of thermal expansion between stainless steel and aluminium, SS304 set screws, nuts and washers are chosen to provide axial sealing force. The sealing ability of this diamond-edge gasket is reliable through tens of bake-out experiments. It is reminded that pre-torque should be sufficient to cause plastic deformation of the diamond-edge gasket and re-torque after baking 24hr and cooling down to room temperature is also important to prevent leaks resulting from loss of torque which usually happen at 100oC.  
 
WEPPD036 Energy Flow and Deposition in a 4-MW Muon Collider Target System target, shielding, collider, radiation 2588
 
  • N. Souchlas, R.J. Weggel
    Particle Beam Lasers, Inc., Northridge, California, USA
  • X.P. Ding
    UCLA, Los Angeles, California, USA
  • V.B. Graves
    ORNL, Oak Ridge, Tennessee, USA
  • H.G. Kirk, H. K. Sayed
    BNL, Upton, Long Island, New York, USA
  • K.T. McDonald
    PU, Princeton, New Jersey, USA
  
  Funding: Work support by the U.S. Department of Energy in part under Award No. DE-AC02-98CH10886
The design of the target station for a 4-MW Muon Collider or a Neutrino Factory is evolving to include more space for services to the magnets and internal tungsten shielding, as well as consideration of removing the 5-T resistive copper coils, thereby reducing the peak field from 20 to 15 T. Simulations with MARS15 have been performed to verify that these revisions preserve sufficient shielding that the peak power deposition everywhere in the superconducting magnets will be less than 0.1 mW/g, permitting at least a 10-year operational lifetime against radiation damage to the organic insulators. 		 
 
WEPPD037 Shielding of Superconducting Coils for a 4-MW Muon-Collider Target System shielding, target, collider, interaction-region 2591
 
  • R.J. Weggel, N. Souchlas
    Particle Beam Lasers, Inc., Northridge, California, USA
  • X.P. Ding
    UCLA, Los Angeles, California, USA
  • V.B. Graves
    ORNL, Oak Ridge, Tennessee, USA
  • H.G. Kirk, H. K. Sayed
    BNL, Upton, Long Island, New York, USA
  • K.T. McDonald
    PU, Princeton, New Jersey, USA
  
  Funding: Work support by the U.S. Department of Energy in part under Award No. DE-AC02-98CH10886
The target system envisioned for a Muon Collider/Neutrino Factory features a liquid Hg jet target immersed in a 20-T solenoidal field. Field quality limits intercoil gaps to ~ 40% of the O.D. of the flanking coils. Longitudinal sag of the tungsten shielding vessels limits their length to ~ 7 m. Support members adequate to resist intercryostat axial forces require an aggregate cross section of ~ 0.1 m2; the cryogenic heat leakage may be large. The innermost shielding vessel wall can be adequately cooled by helium gas only if its pressure is ~ 10 atm and its velocity is ~ 200m/s. However, the analysis in this paper found none of these engineering challenges to be insurmountable. 		 
 
WEPPD038 Mercury Handling for the Target System for a Muon Collider target, shielding, proton, collider 2594
 
  • V.B. Graves
    ORNL, Oak Ridge, Tennessee, USA
  • X.P. Ding
    UCLA, Los Angeles, California, USA
  • H.G. Kirk, H. K. Sayed
    BNL, Upton, Long Island, New York, USA
  • K.T. McDonald
    PU, Princeton, New Jersey, USA
  • N. Souchlas, R.J. Weggel
    Particle Beam Lasers, Inc., Northridge, California, USA
  
  Funding: Work supported in part by US DOE Contract NO.~DE-AC02-98CHI10886 and DE-AC05-00OR22725.
The baseline target concept for a Muon Collider or Neutrino Factory is a free-stream mercury jet within a 20-T magnetic field being impacted by an 8-GeV proton beam. A pool of mercury serves as a receiving reservoir for the mercury and a dump for the unexpended proton beam. Design issues discussed in this paper include the nozzle, splash mitigation in the mercury pool, the mercury containment vessel, and the mercury recirculation system. 		 
 
WEPPD061 Quality Control of Modern Linear Accelerator: Dose Stability Long and Short-term controls, radiation, photon, monitoring 2660
 
  • T.U. Uddin
    NICRH, Dhaka, Bangladesh
  
  Quality Control (QC) data of modern linear accelerators, collected by National Institute of Cancer Research and Hospital, Dhaka, Bangladesh between the years 2006 and 2010, were analyzed. The goal was to provide information for the evaluation and elaboration of QC of accelerator outputs and to propose a method for QC data analysis. Short- and long-term drifts in outputs were quantified by fitting empirical mathematical models to the QA measurements. Normally, long-term drifts were well (≤1.5%) modeled by either a straight line or a single-exponential function. A drift of 2% occurred in 18 ± 12 months. The shortest drift times of only 2–3 months were observed for some new accelerators just after the commissioning but they stabilized during the first 2–3 years. The short-term reproducibility and the long-term stability of local constancy checks, carried out with a sealed plane parallel ion chamber, were also estimated by fitting empirical models to the QC measurements. The reproducibility was 0.3–0.6% depending on the positioning practice of a device. Long-term instabilities of about 0.3%/month were observed for some checking devices.  
 
WEPPD068 High Power Collinear Load Coated with FeSiAl cavity, simulation, linac, resonance 2678
 
  • L.G. Shen, X.L. Fu, Y. Sun, F. Zhang
    USTC/PMPI, Hefei, Anhui, People's Republic of China
  • Y.J. Pei
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Funding: This work is supported by the NSFC (NO. 10775128 and NO.51075381)
Aimed at substituting output coupler to absorb remnant power of the LINAC, collinear load coated with high loss materials is expected to come reality. FeSiAl load is studied. The effect of the coating volume upon the cavity frequency and Q factor is analyzed and the dimension compensations of the cavities are suggested to tune the load cavities at 2856 MHz. Orthogonal Experimental Method is utilized to investigate the sensitivity of permittivity (both real part and imaginary part) and permeability (both real part and imaginary part) to cavity characteristics. Five cavities with different coating dimensions are manufactured and their operating frequencies and Q are measured. Compared with the simulations, they show that the Q factor, which is characterization of the actual attenuation of the FeSiAl, agrees very well with the theoretical value and Q factor of the resonant cavity is measured with the probe method. The relationship between Q factor and the length of the test probe is deduced and eventually the individual Q value of a load cavity is extracted. Simulation shows the FeSiAl load can support average power over 15 kW and the one-way attenuation is about 30 dB. 		 
 
WEPPP046 Nonlinear Dielectric Wakefield Experiment for FACET wakefield, simulation, controls, acceleration 2825
 
  • P. Schoessow, S.P. Antipov, C.-J. Jing, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S. Baturin
    LETI, Saint-Petersburg, Russia
  
  Funding: Work supported by the SBIR Program, US Dept. of Energy.
Recent advances in ferroelectric ceramics have resulted in new possibilities for nonlinear devices for particle accelerator and rf applications. The new FACET (Facility for Advanced Accelerator Experimental Tests) at SLAC provides an opportunity to use the GV/m fields from its intense short pulse electron beams to perform experiments using the nonlinear properties of ferroelectrics. Simulations of Cherenkov radiation in the THz planar and cylindrical nonlinear structures to be used in FACET experiments will be presented. Signatures of nonlinearity are clearly present in the simulations: superlinear scaling of field strength with beam intensity, frequency upshift, and development of higher frequency spectral components. 		 
 
WEPPR100 Short-Range Wakefields of Slowly Tapered Structures wakefield, cavity, focusing, simulation 3174
 
  • B. Podobedov
    BNL, Upton, Long Island, New York, USA
  
  We present new analytical results for short-range geometric wakefields of slowly tapered accelerator structures in 2D geometry.  
 
THPPC059 Design of SLED System with Dual Side-wall Coupling Irises and Biplanar Power Splitter for PAL XFEL coupling, simulation, klystron, cavity 3425
 
  • Y.D. Joo, I. Hwang, C. Kim, B.-J. Lee
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  The SLED system of the PAL XFEL is required to be operated with the RF input power of 80 MW and the pulse width of 4 us. The high RF dose from the RF breakdown at the coupling holes and power splitter prohibits that the original design of the SLED serve this operation condition. To reduce the gradient at the cavity coupling structure, the concept of dual side-wall coupling irises is introduced. In addition, the 3dB splitter is modified with the concept of biplanar coupler structure.  
 
THPPC062 CPI 100kW Klystrons Operation Experiences in NSRRC klystron, cathode, cavity, power-supply 3434
 
  • T.-C. Yu, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Y.-H. Lin, C.H. Lo, M.H. Tsai, Ch. Wang, T.-T. Yang, M.-S. Yeh
    NSRRC, Hsinchu, Taiwan
  
  In 2004, NSRRC had decided to upgrade its traditional copper cavity in storage ring of Taiwan Light Source (TLS) to superconducting cavity for higher beam current, brighter X-ray and more insertion devices. To achieve this, the RF power source-the klystron had been upgraded by intensive cooperation with CPI (Communication & Power Industries) from 70 kW to 100 kW. The same 100 kW klystron would then be also adopted as the RF source in booster in TPS plan. There are total five 100kW CPI klystrons with Model number of VKB-7953B as the power amplifiers in RF facility of NSRRC. Four of the five klystrons have been tested in detail as basic characteristic understanding in custom test stand. Some encountered phenomenon in testing period would be discussed here. In conclusion, these klystrons from CPI is quite load VSWR sensitive while the performance has large difference between them.  
 
THPPD031 Measurement of the Residual Resistivity Ratio of the Bus Bars Copper Stabilizer of the 13 kA Circuits of the LHC quadrupole, dipole, instrumentation, simulation 3572
 
  • A. Apollonio, S.D. Claudet, M. Koratzinos, R. Schmidt, A.P. Siemko, M. Solfaroli Camillocci, J. Steckert, H. Thiesen, A.P. Verweij
    CERN, Geneva, Switzerland
  
  After the incident of September 2008, the operational beam energy of the LHC has been set to 3.5 TeV, since not all joints of the superconducting busbars between magnets have the required quality for 7 TeV operation. This choice is based on simulations to determine the safe current in the main dipole and quadrupole magnets, reproducing the thermal behavior of a quenched superconducting joint by taking into account all relevant factors that affect a possible thermal runaway. One important parameter of the simulation is the RRR (Residual Resistivity Ratio) of the copper stabilizer of the busbar connecting superconducting magnets. A dedicated campaign to measure this quantity for the main 13kA circuits of the LHC on all sectors was performed during the Christmas stop in December 2010 and January 2011. The measurement method as well as the data analysis and results are presented in this paper.  
 
THPPD053 Study on Eddy Current Power Losses in Insulated Core Transformer Primary Coil induction, power-supply, high-voltage, simulation 3632
 
  • L. Yang, X. Liu, Y.Q. Xiong, J. Yang
    Huazhong University of Science and Technology (HUST), Wuhan, People's Republic of China
  • T. Yu
    HUST, Wuhan, People's Republic of China
  
  Insulated core transformer (ICT) high-voltage DC power supply is widely used in electron beam accelerator. With air gap in ICT, the reluctance of magnetic circuit is larger than other transformers, and the transverse magnetic flux leakage around the primary coil is more serious. Because the magnetic flux on the radial direction of coil cannot be ignored, the eddy current loss on the wire should be discussed. In this paper, simulation and analysis of the eddy current loss is presented. The relationship between the sizes of the coil wire is also discussed. An optimal design of the primary coil is shown.  
 
THPPD061 Optimal Design for Resonant Power Transformer impedance, power-supply, controls 3650
 
  • C.-Y. Liu, D.-G. Huang, J.C. Huang
    NSRRC, Hsinchu, Taiwan
  
  The energy and dc to dc conversion of the resonant transformer are required to achieve optimal design and working condition of the resonant region frequency. To meet this requirement, the core loss will be checked first by data book for calculation. Using a reliable precise instrument is needed to scan the resonant cure of the resonant transformer as we designed the resonant cure. We calculated the conduction loss in second design step. We design a resonant transformer which the conduction loss equal core loss does not meet optima design, because the core loss is very high when the transformer works in resonant frequency. Thus, we only reduce the conduction loss is optima design aspect.  
 
THPPD082 A Novel Solid-State Marx Modulator Topology with Voltage Droop Self-Compensation controls, simulation, high-voltage, linac 3707
 
  • P. Chen, M. Lundquist, D. Yu
    DULY Research Inc., Rancho Palos Verdes, California, USA
  
  Funding: Work supported by U.S. Department of Energy SBIR grant no. DE-FG02-08ER85052.
Solid-state Marx modulators are preferred over conventional modulators in accelerators and radar applications because of their high flexibility, high reliability and long life. However, voltage droop is a notable issue. A novel topology of solid-state Marx modulators is described in this paper for raising their electric energy utilization ratios (EEURs). The new Marx modulator incorporates a buck regulator circuit into each Marx cell and adopts a higher charge voltage than that of application. The topology allows Marx cells to store more electric energy and utilize the energy more efficiently than others. Initial theoretical analysis and preliminary experiments show that solid-state Marx modulators constructed with this topology and under proper control of the stepwise energy release are able to significantly enhance their EEURs. The cost effective Marx modulators with compact energy storage sizes will resolve the issue of voltage droop when they are used in high power, long pulse applications. 		 
 
THPPD084 Analysis of Beam Loss Induced Abort Kicker Instability radiation, high-voltage, kicker, electron 3713
 
  • W. Zhang, L. A. Ahrens, W. Fischer, H. Hahn, J.-L. Mi, C. Pai, J. Sandberg, Y. Tan
    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.
Through more than a decade of operation, we have noticed the phenomena of beam loss induced kicker instability in the RHIC beam abort systems. In this study, we analyze the short term beam loss before abort kicker pre-fire events and operation conditions before capacitor failures. Beam loss has caused capacitor failures and elevated radiation level concentrated at failed end of capacitor has been observed. We are interested in beam loss induced radiation and heat dissipation in large oil filled capacitors and beam triggered thyratron conduction. We hope the analysis result would lead to better protection of the abort systems and improved stability of the RHIC operation. 		 
 
THPPP090 Project X Functional Requirements Specification linac, proton, collider, target 3945
 
  • S.D. Holmes, S. Henderson, R.D. Kephart, J.S. Kerby, I. Kourbanis, V.A. Lebedev, C.S. Mishra, S. Nagaitsev, N. Solyak, R.S. Tschirhart
    Fermilab, Batavia, USA
  
  Funding: Work supported by the Fermi Research Alliance, under contract to the U.S. Department of Energy.
Project X is a multi-megawatt proton facility being developed to support a world-leading program in Intensity Frontier physics at Fermilab. The facility is designed to support programs in elementary particle and nuclear physics, with possible applications to nuclear energy research. A Functional Requirements Specification has been developed in order to establish performance criteria for the Project X complex in support of these multiple missions, and to assure that the facility is designed with sufficient upgrade capability to provide U.S. leadership for many decades to come. This paper will describe the Functional Requirements for the Project X facility, their recent evolution, and the rationale for these requirements. 		 
 
THPPR009 Optimization of the Electron Beam Extraction Efficiency in a Booster for TLS extraction, electron, booster, kicker 3981
 
  • H.C. Chen, H.-P. Chang, H.H. Chen, S. Fann, S.J. Huang, J.A. Li, C.C. Liang, Y.K. Lin, Y.-C. Liu
    NSRRC, Hsinchu, Taiwan
  
  The Response Surface Methodology (RSM), is used to study the optimization process of the electron beam extraction efficiency for Taiwan Light Source (TLS) in NSRRC. A study model was constructed based on the Artificial Neural Network (ANN) theory by using selected beam extraction tuning knobs as the variables. An optimization procedure is developed by taking extraction efficiency as the objective function and the selected beam tuning knobs as the variables. Furthermore, this theoretical model and optimization procedure have been put into practice in verifying how effectively the model can accomplish. By properly applying the constructed optimization procedure for electron beam extraction study, the efficiency has been improved effectively. The details of the study will be reported in this paper.