Keyword: focusing
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MOYCP01 Design and Simulation of IOTA - a Novel Concept of Integrable Optics Test Accelerator electron, betatron, optics, simulation 16
 
  • S. Nagaitsev, A. Valishev
    Fermilab, Batavia, USA
  • V.V. Danilov
    ORNL, Oak Ridge, Tennessee, USA
  • D.N. Shatilov
    BINP SB RAS, Novosibirsk, Russia
  
  The use of nonlinear lattices with large betatron tune spreads can increase instability and space charge thresholds due to improved Landau damping. Unfortunately, the majority of nonlinear accelerator lattices turn out to be nonintegrable, producing chaotic motion and a complex network of stable and unstable resonances. Recent advances in finding the integrable nonlinear accelerator lattices have led to a proposal to construct at Fermilab a test accelerator with strong nonlinear focusing which avoids resonances and chaotic particle motion. This presentation will outline the main challenges, theoretical design solutions and construction status of the Integrable Optics Test Accelerator underway at Fermilab.  
slides icon Slides MOYCP01 [2.816 MB]  
 
MOPPC034 Use of Helical Transport Channels for Bunch Recombination simulation, collider, luminosity, emittance 205
 
  • D.V. Neuffer, K. Yonehara
    Fermilab, Batavia, USA
  • C.M. Ankenbrandt, C. Y. Yoshikawa
    Muons, Inc, Batavia, USA
  
  Cooling scenarios for a high-luminosity Muon Collider require bunch recombination for optimal luminosity. In this paper we describe a new method for bunch recombination. We combine the high-chronicity of a helical transport channel (HTC) with the high-frequency bunching and phase-energy rotation concept (time-reversed) to obtain a compact bunch recombination system adapted to a muon collider scenario. We first present an idealized 1-D system with multiple chronicity transports. We then implement the concept in a single-chronicity channel, obtaining bunch recombination of 13 200MHz-spaced bunches to a single collider-ready bunch within a compact transport with modest rf requirements. That example is demonstrated within G4BL 3-D simulations. Variations and adaptations for different recombination requirements are discussed.  
 
MOPPC072 Mathematical Model of Charged Particles Dynamics Optimization in RFQ Accelerators rfq, emittance, controls, resonance 298
 
  • A.D. Ovsyannikov
    St. Petersburg State University, St. Petersburg, Russia
  
  Mathematical model of optimization of transverse motion of charged particles in accelerators is suggested. Linear and nonlinear systems are considered when describing the transverse motion. Interaction of the particles is taken into account. Optimization algorithm based on minimax functionals is built. Numerical results for RFQ accelerators are presented.  
 
MOPPD018 A FFAG Design Study for an Accelerator-driven System proton, synchrotron, resonance, acceleration 403
 
  • T.-Y. Lee, H.-S. Kang, H.-S. Lee
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  Design of a 1 GeV FFAG accelerator is studied for the accelerator-driven sub-critical nuclear reactor system. Scaling and non-scaling lattices are studied and compared with each other. Corresponding magnet design and RF system are considered.  
 
MOPPD026 A Superconducting Ring Cyclotron for the DAEδALUS Experiment cyclotron, extraction, proton, injection 421
 
  • L. Calabretta
    INFN/LNS, Catania, Italy
  • A. Calanna, D. Campo
    CSFNSM, Catania, Italy
  • M.M. Maggiore, L.A.C. Piazza
    INFN/LNL, Legnaro (PD), Italy
  • F. Méot
    BNL, Upton, Long Island, New York, USA
  
  Funding: Istituto Nazionale Fisica Nucleare - Laboratori Nazionali del Sud.
The experiment DAEδALUS*, proposed by MIT scientist to search for CP violation in the neutrino sector, needs three accelerator with energy of about 800 MeV, average power of some MW and duty cycle of 20%. To reduce the cost of the accelerators a cyclotron complex consisting of an injector** and of a booster ring cyclotron has been proposed***. The booster Superconducting Ring Cyclotron is able to accelerate a H2+ molecule beam up to 800 MeV/n with a peak current of 10 mA and average power higher than 1.6 MW. To simplify the design of the superconducting magnetic coils, to minimize the radial force shift and to increase the room to host the RF cavities, the previous study has been updated increasing the injection energy of the H2+ and also the injection energy. The updated study on the magnetic sector configuration, on the superconducting coils and the magnetic forces are presented. The isochronous magnetic field, the beam dynamics along the injection and extraction path and during the acceleration are presented, too.
* J. Alonso et al., Jun2010 e-Print: arXiv:1006.0260
** L. Calabretta, Proc. IPAC 2011, WEPS073 (2011).
*** L. Calabretta, Cyclotrons 2010, Lanzhou.
 		 
 
MOPPD033 Strong-focusing Cyclotron - High-current Applications cyclotron, dipole, proton, cavity 436
 
  • P.M. McIntyre, S. Assadi, K.E. Badgley, C. Collins, J. Comeaux, R. Garrison, J.N. Kellams, T.L. Mann, A.D. McInturff, N. Pogue, A. Sattarov
    Texas A&M University, College Station, Texas, USA
  
  Funding: This work is supported by grants from the State of Texas (ASE) and from the Mitchell Family Foundation.
Quadrupole focusing channels are integrated into the pole faces of a superconducting sector cyclotron, to enable control of the betatron tunes for all orbits. This provision makes it possible to lock the tunes to desired values for all orbits, thereby eliminating resonance crossing and facilitating local orbit bumps for injection and extraction. Optical control is of particular importance for applications where higher beam current is desired, for ADS fission drivers, for spallation neutron sources, and for medical isotope production. 		 
 
MOPPD034 Flux-coupled Stacking of Cyclotrons for a High-power ADS Fission Driver cyclotron, injection, cavity, target 439
 
  • A. Sattarov, S. Assadi, K.E. Badgley, J.N. Kellams, T.L. Mann, A.D. McInturff, P.M. McIntyre, N. Pogue
    Texas A&M University, College Station, Texas, USA
  
  Funding: This work is funded by grants from the State of Texas (ASE) and the Mitchell Family Foundation.
The sector magnets for an isochronous cyclotron are configured as a flux-coupled stack of apertures, each forming an independent cyclotron, separated sufficiently to accommodate independent superconducting rf cavities. The stack strategy makes it possible to deliver any amount of proton beam power consistent with the limitations of each individual cyclotron, and to deliver the aggregate power to a number of spallation targets as dictated by optimum coupling for accelerator-driven subcritical (ADS) fission and by limitations in target transfer. 		 
 
MOPPD036 Gabor Lens Focusing for Medical Applications ion, laser, proton, space-charge 442
 
  • J.K. Pozimski, M. Aslaninejad
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  The widespread introduction of Hadron therapy for cancer treatment is inhibited by the large costs for the accelerator and treatment facility and the subsequent maintenance costs which reflects into the cost per treatment. In the long term future (laser) plasma wakefield accelerated hadrons could offer compact treatment devices with significantly reduced treatment costs. In the moment the particle distributions produced by such accelerators do not fulfill the medical requirements by far. Never the less steady progress on the field might change the situation in the future. Beside the reliable production of a sufficient number of ions at the required energy the formation of a particle beam suitable for treatment from the burst of ions created in the acceleration process is one of the major challenges. While conventional optical systems will be operating at the technical limits which would be contradictory to the cost argument, space charge lenses of the Gabor type might be a cost effective alternative. In this paper a beam line consisting of such lenses will be presented together with particle transport simulations.  
 
MOPPD044 Optimization of the Target Subsystem for the New g-2 Experiment target, proton, simulation, factory 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.  
 
MOPPD050 Dipole Magnet Design for a Bunch Compressor dipole, neutron, linac, proton 478
 
  • T. Kanesue, L.P. Chau, O. Meusel, D. Noll, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  The FRANZ-ARMADILLO is a Mobley type bunch compressor system at the pulsed intense neutron source FRANZ, under construction at Frankfurt University. The FRANZ-ARMADILLO compresses 9μbunches of a 150 mA, 2 MeV proton beam accelerated by a 175 MHz linac into one short pulse of 1 ns pulse length with 250 kHz repetition rate. In the bunch compressor, two homogeneous dipole magnets and two gradient dipole magnets guide theμbunches, separated by a 5 MHz RF-kicker on individual tracks. The flight path length of theμbunches are determined based on the bunch center velocity and the linac frequency for the longitudinal bunch compression. The gradient dipole magnets provide individual magnetic fields and edge focusing forces to everyμbunch. For the center trajectory, the required parameters are a magnetic field density of 509.2 mT, bending angle of 78.27 deg, and bending radius of 404.5 mm. To satisfy all specifications, field clamps, shims, and chamfer cut will be adopted. The result of the gradient dipole magnet design and the expected performance based on beam dynamics studies will be presented.  
 
MOPPR092 SVD-BASED METHOD FOR MEASUREMENT OF BEAM PARAMETERS AND FLAG RESOLUTION emittance, quadrupole, simulation, booster 999
 
  • G.M. Wang, R.P. Fliller, I. Pinayev, T.V. Shaftan
    BNL, Upton, Long Island, New York, USA
  
  In NSLS II booster to storage ring transport line, the typical beam size in vertical plane is ~60 μm, which requires very high flag resolution to get good beam parameters measurement. This paper describes a new SVD-based method to measure transverse beam parameters and flag resolution simultaneously with double quads scan. Implementation simulations of the proposed method are performed for a dispersion free region in the NSLS-II booster to storage ring transport line. With this method, it breaks the limitation of beam parameters measurement accuracy duo to the flag resolution.  
 
TUYB03 FFAG Experience and Future Prospects acceleration, proton, betatron, lattice 1054
 
  • Y. Mori
    Kyoto University, Research Reactor Institute, Osaka, Japan
  
  This talk should outline the various FFAG accelerators that have been constructed, and discuss the operational experience with different machines. Common issues should be identified, and contrasting experiences highlighted. A frank assessment of the capability of FFAGs to meet the requirements for applications such as ion therapy, accelerator-driven subcritical reactors, and muon colliders should be followed by a description of the main objectives and challenges for future R&D.  
slides icon Slides TUYB03 [14.162 MB]  
 
TUOAA02 Focusing Charged Particle Beams Using Multipole Magnets in a Beam Transport Line sextupole, multipole, octupole, target 1062
 
  • Y. Yuri, I. Ishibori, T. Ishizaka, S. Okumura, T. Yuyama
    JAEA/TARRI, Gunma-ken, Japan
  
  The intensity distribution of a charged-particle beam is transformed by applying the nonlinear focusing force of a multipole magnet. In this paper, the transformation of the transverse intensity distribution due to the second-order sextupole and third-order octupole focusing force in the beam transport line is explored. As a measure of the distribution transformation induced by the multipole magnets, the beam centroid displacement and the change of the beam size have been analytically derived using the distribution function of the beam. It is numerically verified how the transverse distribution of the beam is transformed by the multipole magnets. As an application of the distribution transformation by nonlinear focusing, a uniform beam can be formed from a Gaussian beam using multipole magnets. The current status and future plan of the experiment on the uniform-beam formation at the cyclotron facility in Japan Atomic Energy Agency will be shown.  
slides icon Slides TUOAA02 [2.032 MB]  
 
TUEPPB003 Nonlinear Accelerator with Transverse Motion Integrable in Normalized Polar Coordinates lattice, simulation, insertion, damping 1116
 
  • T.V. Zolkin
    University of Chicago, Chicago, Illinois, USA
  • Y. Kharkov, I.A. Morozov
    BINP SB RAS, Novosibirsk, Russia
  • S. Nagaitsev
    Fermilab, Batavia, USA
  
  Several families of nonlinear accelerator lattices with integrable transverse motion were suggested recently*. One of the requirements for the existence of two analytic invariants is a special longitudinal coordinate dependence of fields. This paper presents the particle motion analysis when a problem becomes integrable in the normalized polar coordinates. This case is distinguished from the others: it yields an exact analytical solution and has a uniform longitudinal coordinate dependence of the fields (since the corresponding nonlinear potential is invariant under the transformation from the Cartesian to the normalized coordinates). A number of interesting features are revealed: while the frequency of radial oscillations is independent of the amplitude, the spread of angular frequencies in a beam is absolute. A corresponding spread of frequencies of oscillations in the Cartesian coordinates is evaluated via the simulation of transverse Schottky noise.
V. Danilov and S. Nagaitsev, Phys. Rev. ST Accel. Beams 13 084002 (2010). 		 
 
TUPPC007 Electron Cloud Dynamics in a Gabor Space Charge Lens electron, space-charge, plasma, ion 1164
 
  • K. Schulte, M. Droba, B. Glaeser, S. Klaproth, O. Meusel, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  Inside Gabor space charge lenses, external fields confine electrons forming a homogeneously distributed electron cloud. Its linear electric space charge field enables the focusing of high intensity heavy ion beams without aberrations. The focusing performance depends on the properties of the non-neutral plasma. In a small-scale table top experiment, different types of space charge lenses are used to characterize the collective behavior of the confined electron cloud using new non-interceptive diagnostic methods. The plasma parameters, e.g. electron temperature and density, are important to an improved understanding of loss and production mechanisms as well as the electron cloud dynamics. In this context, the evolution of instabilities caused by the enclosing fields has been investigated in detail. Experimental results will be presented and compared to numerical simulations.  
 
TUPPC009 Dihedral Group and Repetitive Achromats with Mirror Symmetric or Mirror Antisymmetric Basic Cell multipole, electron, resonance, free-electron-laser 1170
 
  • V. Balandin, R. Brinkmann, W. Decking, N. Golubeva
    DESY, Hamburg, Germany
  
  Using the group-theoretical point of view for the design of magnetic optical achromats as introduced in*, we study in this paper second- and third-order repetitive achromats with a mirror symmetric or mirror antisymmetric basic cell. We also compare these achromats with repetitive achromats designed without internal cell symmetries taken into account.
* V.Balandin, R.Brinkmann, W.Decking, N.Golubeva. Two Cell Repetitive Achromats and Four Cell Mirror Symmetric Achromats, Proceedings of IPAC'10, Kyoto, Japan.
 		 
 
TUPPC010 Study of Effects of Failure of Beamline Elements and its Compensation in CW Superconducting Linac linac, cavity, beam-losses, emittance 1173
 
  • A. Saini, K. Ranjan
    University of Delhi, Delhi, India
  • C.S. Mishra, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  Project-X is the proposed high intensity proton facility to be built at Fermilab in United States. First stage of the Project-X consists of H- superconducting linac (SC) which will be operated in continuous wave (CW) mode to accelerate the beam from kinetic energy of 2.1 MeV to 3 GeV. The operation in CW mode puts stringent tolerances on the beam line components, particularly at low energy section. The failure of beam line elements result in mismatch of the beam with the following sections due to different beam parameters than designed parameters. It makes the beam unstable which causes emittance dilution, and ultimately results in beam losses. In worst case, it can affect the reliability of the machine and may lead to the shutdown of the linac to replace the failed elements. Thus, it is important to study impacts of these effects and their compensation to restore linac performance to avoid beam interruption. This paper presents the studies performed for the failure of accelerating cavity and focusing magnets at the critical locations in the Project-X CW superconducting linac  
 
TUPPC026 Design of Compact C-Band Standing-Wave Accelerating Structure Enhancing RF Phase Focusing coupling, bunching, cavity, simulation 1221
 
  • H.R. Yang, M.-H. Cho, J. Jang, S.H. Kim, W. Namkung, S.J. Park
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • J.-S. Oh
    NFRI, Daejon, Republic of Korea
  
  Funding: Work supported by POSTECH Physics BK21 Program.
We design a C-band standing-wave accelerating structure for an X-ray source of the imaging and medical applications. It is capable of producing 6-MeV, 100-mA pulsed electron beams which is focused by less than 1.5 mm without external magnets. As an RF source, we use peak 1.5-MW magnetron with duty factor of 0.08%. The accelerating structure is a bi-periodic and on-axis-coupled structure with a built-in bunching section, which consists 3 bunching cells, 13 normal cells and a coupler cell. It operated with π/2-mode standing-waves. The bunching section is designed to enhance the RF phase focusing in order to achieve 1.2-mm beam spot size. Each cavity is designed with the MWS code to maximize the effective shunt impedance within 3.5% inter-cell coupling. In this paper, we present design details of RF cavities and the beam dynamics simulation by the PARMELA code. 		 
 
TUPPC035 Design of a Surface Muon Beam Line for High Field muSR at the PSI Proton Accelerator Facility simulation, quadrupole, proton, secondary-beams 1236
 
  • D. Reggiani, K. Deiters, P. Kaufmann, Y. Lee, T. Prokscha, T. Rauber, R. Scheuermann, K. Sedlak, V. Vranković
    Paul Scherrer Institut, Villigen, Switzerland
  
  Starting from 2012, a high field muSR (muon spin rotation/relaxation/resonance) facility will come into operation in the piE3 secondary beam line located at the target station E of the PSI proton accelerator. For this purpose, the last part of the beam line has been redesigned in order to integrate two electrostatic spin rotator devices providing a 90° rotation of the muon spin. At the same time, requirements of small beam diameter (σ ≈ 10 mm) as well as small momentum bite (δp/p ≈ 1%) in the sample region have to be met. This work focuses on the simulation of the beam optics (28 MeV/c design momentum). Particular concern is given to potential transmission losses caused by the spin rotator devices. The matching of the beam line with the high magnetic field up to 9.5 T surrounding the sample region has been considered as well. An overview of the spin rotator devices, specifically designed for this project, is also presented.  
 
TUPPC044 Emittance and Phase Space Tomography for the Fermilab Linac emittance, linac, optics, quadrupole 1263
 
  • C. Johnstone, F.G.G. Garcia, T. Kobilarcik, G.M. Koizumi, C.D. Moore, D.L. Newhart
    Fermilab, Batavia, USA
  
  Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Dept. of Energy.
The Fermilab Linac delivers a variable intensity, 400-MeV beam to the The MuCool Test Area experimental hall via a beam line specifically designed to facilitate measurements of the Linac beam emittance and properties. A 10 m, dispersion-free and magnet-free straight utilizes an upstream quadrupole focusing triplet in combination with the necessary in-straight beam diagnostics to fully characterize the transverse beam properties. Since the Linac does not produce a strictly elliptical phase space, tomography must be performed on the profile data to retrieve the actual particle distribution in phase space. This is achieved by rotating the phase space distribution using different waist focusing conditions of the upstream triplet and performing a de-convolution of the profile data. Preliminary measurements using this diagnostic section are reported here. 		 
 
TUPPC054 Beam Acceleration by a Multicell RF Cavity Structure Proposed for Improved Yield in Hydroforming cavity, electron, acceleration, quadrupole 1293
 
  • J.A. Holmes, Y.W. Kang
    ORNL, Oak Ridge, Tennessee, USA
  • A.E. Fathy, K.R. Shin
    University of Tennessee, Knoxville, Tennessee, USA
  
  Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
We study the accelerating properties of a new multicell cavity structure with irises forming a rectangular aperture between the cavity cells. We are interested in this structure because, from a mechanical point of view, the rectangular iris may make possible a much improved structure quality using a hydroforming manufacturing process. RF analysis shows that the rectangular iris shape provides asymmetric transverse focusing per half RF period. If the horizontal and vertical rectangular irises are interleaved, the net transverse focusing can be increased. The present studies of the acceleration and transport properties of these cavities are conducted by tracking particles through time-dependent 3D cavity fields from CST MWS using the ORBIT Code. 		 
 
TUPPC069 Third-Order Apochromatic Drift-Quadrupole Beamline quadrupole, betatron, beam-transport, resonance 1329
 
  • N. Golubeva, V. Balandin, R. Brinkmann, W. Decking
    DESY, Hamburg, Germany
  
  We have shown that for every drift-quadrupole system there exists an unique set of Twiss parameters (apochromatic Twiss parameters), which will be transported through that system without first order chromatic distortions*. In this paper we continue the development of the theory of apochromatic focusing and present the design of a straight drift-quadrupole system which can transport apochromatic beam ellipses without influence not only of the second but also of the third order chromatic and geometric aberrations of the beamline transfer map.
* V.Balandin, R.Brinkmann, W.Decking, N.Golubeva. Apochromatic Beam Transport in Drift-Quadrupole Systems. Proceedings of IPAC'10, Kyoto, Japan.
 		 
 
TUPPC075 Study of Nonlinear Beam Dynamics Effects for DEPU at SSRF polarization, undulator, electron, photon 1347
 
  • M. Zhang, Q.G. Zhou
    SINAP, Shanghai, People's Republic of China
  
  A pair of EPUs (DEPU) with the period 58mm and 148mm, covering the energy ranges from 20 to 200eV and 200 to 2000eV of arbitrary polarized light, will be developed for the SSRF soft X-ray beam line for ARPES and PEEM. The effects of DEPU to tune-shift produced by the nonlinear beam dynamics are studied and the results are presented in this paper. The corresponding magnet field shimming technology to reduce these effects is also investigated.  
 
TUPPC100 On Quantum Integrable Systems lattice, plasma, synchrotron, betatron 1392
 
  • V.V. Danilov
    ORNL, Oak Ridge, Tennessee, USA
  • S. Nagaitsev
    Fermilab, Batavia, USA
  
  Funding: This research is sponsored by Oak Ridge National Lab, under Contract No. DE-AC05-00OR22725, and Fermi National Lab, under Contract No. DE-AC02-07CH11359.
Many quantum integrable systems are obtained using an accelerator physics technique known as Ermakov (or normalized variables) transformation. This technique was used to create classical nonlinear integrable lattices for accelerators and nonlinear integrable plasma traps. Now, all classical results are carried over to a nonrelativistic quantum case. 		 
 
TUPPC101 A Model of the AGS Based on Stepwise Ray-Tracing Through the Measured Field Maps of the Main Magnets resonance, quadrupole, sextupole, simulation 1395
 
  • Y. Dutheil, F. Méot, N. Tsoupas
    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 dimensional mid-plane magnetic field maps of two of the main AGS magnets were produced, from Hall probe measurements, for a series of different current settings. The analysis of these data yielded the excitation functions and harmonic coefficients of the main magnets [BNL TN 424 & TN 429] which have been used so far in all the models of the AGS. The constant increase of computation power makes it possible today to directly use stepwise ray-tracing through these measured field maps with a reasonable computation time. We describe in detail how these field maps have allowed generation of models of the 6 different types of AGS main magnets, and how they are being handled with the Zgoubi ray-tracing code. We give and discuss a number of results so obtained regarding both beam and spin dynamics in the AGS, and provide comparisons with other numerical and analytical modeling methods. 		 
 
TUPPD014 To the Ionization Cooling in a RF Cavity with Absorber cavity, scattering, radiation, emittance 1437
 
  • A.A. Mikhailichenko
    CLASSE, Ithaca, New York, USA
  
  We are considering a RF cavity with Beryllium disk installed in the middle of the cavity as a ionization cooling element for the muon beam. Specially arranged shape of disk together with nonzero dispersion allows 6D cooling of muon beam. Technical aspects of this system and conceptual design are discussed in this paper also. This type of cooler demonstrates advantages if compared with the RF cavity filled with pressurized gas or with the helical cooler.  
 
TUPPD016 Collection Optics with the Horn Type Focusing Element made with Separate Conductors positron, secondary-beams, optics, scattering 1443
 
  • A.A. Mikhailichenko
    CLASSE, Ithaca, New York, USA
  
  We describe the device for focusing of charged particles by the system of separated conductors which follow the parabolic profile. Basically this is a horn-type focuser, but with the individual conductors instead of continuous surface. This device allows substantial reduction of fabrication cost with the same focusing properties as the continuous parabolic surface. We recommend this “bird-cage” type system for focusing pions/muons in the projects under discussion in many Laboratories around the World.  
 
TUPPD039 Simulation Study of Space Charge Effects for a 100-keV, 150-mA Class Deuteron Source emittance, extraction, simulation, plasma 1491
 
  • M. Ichikawa, H. Suzuki
    Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan
  • S. Maebara
    JAEA, Ibaraki-ken, Japan
  
  Ion sources providing high current beam with low emittance are required for accelerators to expand to apply them to fusion material science. A 100-keV, 150-mA class deuteron source with low emittance is required for an accelerator-based neutron irradiation facility to develop fusion materials, and the study for space charge effects in the range of a 20- to 150-mA deuteron beam is indispensable to extract the low beam emittance. For this purpose, each ion source to extract the beam current of 20, 50, 100, and 150 mA was designed by the Igun code, under the condition to extract a beam radius of 4 mm, a beam energy of 100 keV, and a normalized emittance of 0.2 PI mm mrad. In this article, these simulation results from the viewpoint of space charge effects will be presented in detail.  
 
TUPPD075 Simulated Performance of the Wisconsin Superconducting Electron Gun emittance, solenoid, simulation, quadrupole 1572
 
  • R.A. Bosch, K.J. Kleman
    UW-Madison/SRC, Madison, Wisconsin, USA
  • R.A. Legg
    JLAB, Newport News, Virginia, USA
  
  The Wisconsin superconducting electron gun is modeled with multiparticle tracking simulations using the ASTRA and GPT codes. To specify the construction of the emittance-compensation solenoid, we studied the dependence of the output bunch's emittance upon the solenoid's strength and field errors. We also evaluated the dependence of the output bunch's emittance upon the bunch's initial emittance and the size of the laser spot on the photocathode. The results suggest that a 200-pC bunch with an emittance of about one mm-mrad can be produced for a free-electron laser.  
 
TUPPP082 Optimization of a Terawatt Free Electron Laser undulator, FEL, electron, radiation 1780
 
  • J. Wu, X. Huang, Y. Jiao, A.U. Mandlekar, T.O. Raubenheimer, S. Spampinati, G. Yu
    SLAC, Menlo Park, California, USA
  • P. Chu
    FRIB, East Lansing, Michigan, USA
  • J. Qiang
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515.
There is great interest in generating a terawatt (TW) hard X-ray free electron laser (FEL) that will enable coherent diffraction imaging of complex molecules like proteins and probe fundamental high-field physics. A feasibility study of producing such pulses was carried out em- ploying a configuration beginning with an SASE amplifier, followed by a "self-seeding" crystal monochromator, and finishing with a long tapered undulator. The undulator tapering profile, the phase advance in the undulator break sections, the quadrupole focusing strength, etc. are parameters to be optimized. A genetic algorithm (GA) is adopted for this multi-dimensional optimization. Concrete examples are given for LCLS/LCLS-II systems. 		 
 
TUPPP083 Multi-Dimensional Optimization of a Tapered Free Electron Laser undulator, radiation, FEL, electron 1783
 
  • Y. Jiao, J. Wu
    SLAC, Menlo Park, California, USA
  • Q. Qin
    IHEP, Beijing, People's Republic of China
  
  Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. In this paper, we report a multi-dimensional optimizer to maximize the radiation power in a tapered FEL by searching for an optimal taper profile as well as a reasonable variation in electron beam radius. Applications of the proposed multi-dimensional optimization to the terawatt-level, tapered FELs with LCLS-like electron beam parameters are presented, and the proposed optimization scheme is compared with the GINGER’s self-design taper algorithm. At the end, the dependence of the available maximum radiation power on various parameters of the initial electron beam, the initial radiation field and the undulator system is summarized.  
 
WEPPC044 Multipole Effects Study for Project X Front End Cavities cavity, multipole, quadrupole, linac 2309
 
  • P. Berrutti, M.H. Awida, I.V. Gonin, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  Effects of RF field asymmetry along with multipoles have been studied in Project X front end cavities. One family of half wave resonators operating at 162.5 and two of spoke resonators operating at 325 MHz have been analysed. HWR and spoke resonators unlike elliptical cavities, do not have axial symmetry, hence a quadrupole perturbation to the beam is present. The purpose of this paper is to explain the approach and the calculation method used to understand and overcome the drawbacks due to the RF field asymmetry.  
 
WEPPC046 Overview of Project X Superconducting RF Cavities and Cryomodules cavity, cryomodule, linac, SRF 2315
 
  • T.N. Khabiboulline, M.S. Champion, C.M. Ginsburg, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  The Project X Linac is based primarily on superconducting RF technology starting from a low beam energy of approximately 2.5 MeV up to the exit energy of 8 GeV. The Linac consists of 162.5 MHz half-wave cavities, 325 MHz single-spoke cavities, and two families of 650 MHz elliptical cavities - all operating in continuous-wave mode - up to a beam energy of 3 GeV. The beam is further accelerated up to 8 GeV in a pulsed mode ILC-like Linac utilizing 1.3 GHz cavities. In this paper we will give an overview of the design and status of the Project X superconducting RF cavities and cryomodules.  
 
WEPPC047 Effects of the RF Field Asymmetry in SC Cavities of the Project X linac, cavity, multipole, acceleration 2318
 
  • I.V. Gonin, M.H. Awida, P. Berrutti, A. Saini, B.G. Shteynas, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
  • P.N. Ostroumov
    ANL, Argonne, USA
  
  The low-energy SCRF section of CW SC linac of Project X starts from Half Wave Resonators (HWR) having operating frequency f=162.5 MHz, optimal β= 0.11 and will accelerate the beam from 2 MeV up to 11 MeV. The preliminary analysis of beam dynamics shows that multipole effects caused by asymmetry of RF fields in HWR cavities aren’t negligible. In this paper we present the analysis of influence of multipole effects on beam dynamics and discuss the possible solutions how to compensate these effects.  
 
WEPPC063 Superconducting RF Cavity for High-current Cyclotrons cavity, cyclotron, extraction, injection 2354
 
  • N. Pogue, P.M. McIntyre, A. Sattarov
    Texas A&M University, College Station, Texas, USA
  
  Funding: This work is supported by grants from the State of Texas (ASE) and the Mitchell Family Foundation.
A novel superconducting cavity is presented for applications in cyclotrons. The cavity is in effect an extrusion of a 2-D double-quarter-wave structure, in which the ends of the extrusion are wrapped around and joined so that the cavity has no end perturbations. Power is applied to a linear array of input coupling loops, so that rf sheet current is launched in a laminar flow that matches the power coupled to the orbits of the cyclotron. Each loop is driven by an independent solid-state rf source. A strategy is presented for using to advantage the independent control of phase and amplitude to suppress transient phenomena. Longitudinal modes can be strongly suppressed. These provisions are of importance to suppress phenomena that can limit beam current. 		 
 
WEPPD065 Development of a Laser-based Alignment System Utilizing Fresnel Zone Plates at the KEKB Injector Linac laser, alignment, scattering, linac 2672
 
  • T. Suwada, M. Satoh
    KEK, Ibaraki, Japan
  • K. Minoshima, S. Telada
    AIST, Tsukuba, Japan
  
  A new laser-based alignment system is under development in order to precisely align accelerator components along an ideal straight line at the 600-m-long KEKB injector linac. A well-known sequential three-point method with Fresnel zone plates and a CCD camera is revisited in the alignment system. The high-precision alignment system is strongly required in order to stably accelerate high-brightness electron and positron beams with high bunch charges and also to keep the beam stability with higher quality towards the Super B-factory at KEK. A new laser optics has been developed and the laser propagation characteristics has been systematically investigated at a 100-m-long straight section in vacuum. In this report, the experimental developments and investigations are reported along with the design of the new laser-based alignment system.  
 
WEPPP003 Focusing of Accelerated Particles by Wakefields of a Drive Bunch in a Plasma-dielectric Waveguide plasma, wakefield, electron, acceleration 2723
 
  • G.V. Sotnikov, R.R. Kniaziev
    NSC/KIPT, Kharkov, Ukraine
  
  Funding: The research is supported in part by the Science and Technology Center in Ukraine (STCU), project No. P522.
One of wakefield acceleration methods as a slowing medium uses the plasma of a capillary discharge*. The capillary tube is a slowing medium, therefore at propagation in it of a laser pulse or relativistic electron bunches (REB) along with plasma wakefields will be excited an eigen waves of dielectric structure. So far influence of electrodynamic properties of capillary tube material on plasma wakefields is not investigated. On an example of a cylindrical waveguide of gigahertz operation frequency range, we investigate excitation of wakefields by REB in a dielectric waveguide (DW) with the accelerating channel filled with isotropic plasma. The excited field consists of Langmuir wave fields (LW) and fields of eigen waves of DW. At certain plasma density a longitudinal electric field of LW it is significantly less than the similar of DW waves , and transverse components of the LW field are significantly higher than transverse component of DW waves. The periods of these two types of waves generally do not coincide. The range of plasma densities which provides a simultaneous acceleration and focusing of test bunch by LW is found.
* Steinhauer L.C., Kimura W.D. Phys. Rev. STAB. V.9, 081301 (2006). 		 
 
WEPPP012 High-Gradient THz-Scale Two-Channel Coaxial Dielectric-Lined Wakefield Accelerator wakefield, acceleration, radiation, vacuum 2747
 
  • S.V. Shchelkunov, M.A. LaPointe
    Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
  • J.L. Hirshfield, T.C. Marshall
    Omega-P, Inc., New Haven, USA
  • G.V. Sotnikov
    NSC/KIPT, Kharkov, Ukraine
  
  Funding: Research is supported by U.S. Department of Energy, Office of High Energy Physics.
A mm-scale THz Coaxial Dielectric Wakefield Accelerator structure is currently under study by Yale University Beam Physics Lab and collaborators for its performance with annular drive bunches. With our recent successful experiments with the cm-scale GHz rectangular module at AWA/Argonne (USA) and planned activity there with yet another cm-scale GHz coaxial structure, the program of new research has two objectives. The first is to design a structure to produce acceleration gradients approaching 0.35 GeV/m per each nC of drive charge when excited by an annular-like bunch; has an attractive feature that the drive and accelerated bunches both have good focusing and stability properties; and also exhibits a large transformer ratio. The second goal is to build and test the structure at FACET/SLAC (USA). At FACET the structure can be excited only with the available pencil-like drive bunch, but the reciprocity principle allows one to observe some of the properties that would be seen if the excitation were to be by an annular drive bunch. This presentation shows our latest findings, discusses related issues, and discusses our plans for experiments. 		 
 
WEPPP016 De-neutralization of Laser Produced Proton Pulse in a Strong Solenoidal Magnetic Field electron, proton, simulation, laser 2755
 
  • M. Droba, O.K. Kester, O. Meusel, C. Wiesner
    IAP, Frankfurt am Main, Germany
  
  Laser generated proton pulses of ten to several ten MeV produced in PHELIX-laser facility at GSI Darmstadt poses some unique characteristics. The first systematic exploration of the interface between proton pulse generation via the TNSA mechanism and conventional accelerator technology is within the scope of the LIGHT (Laser Ion Generation, Handling and Transport) project. One of the main tasks is to study the beam dynamics in intense B-fields, especially in context of early de-neutralization and space charge effects. The 3D numerical simulations with co-moving electrons and up to 107 macroparticles were performed to investigate the de-neutralization process in the focusing magnetic solenoid. Importance of the first focusing element and influence on beam parameters will be addressed. Results of the 3D simulation model will be presented and discussed.  
 
WEPPP020 Rebunching Low Energy Neutrons by Magnetic Acceleration and Deceleration neutron, dipole, acceleration, controls 2766
 
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  • Y. Arimoto, H.M. Shimizu
    KEK, Ibaraki, Japan
  • P.W. Geltenbort
    ILL, Grenoble, France
  • S. Imajo
    Kyoto University, Kyoto, Japan
  • M. Kitaguchi
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • Y. Seki
    RIKEN Nishina Center, Wako, Japan
  • T. Yoshioka
    Kyushu University, Fukuoka, Japan
  
  Funding: Supported by the Grant-in-Aid for Creative Scientific Research of MEXT under the Program 19GS0210, the Quantum Beam Fundamentals Development Program of the MEXT, and KEK Neutron Program 2009S03.
Ultra cold neutrons (UCN) - neutrons with energies less than 300 neV - can be accelerated or decelerated by means of static magnetic and RF fields. The method and experimental setup will be described in detail and the results of a recent first test experiment will be presented. The detail cannot be disclosed until the paper is published. 		 
 
WEPPP030 Experimental Generation of a Double-bunch Electron Beam by Transverse-to-Longitudinal Phase Space Exchange laser, electron, cathode, gun 2789
 
  • T.J. Maxwell, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • A.S. Johnson, A.H. Lumpkin, J. Ruan, Y.-E. Sun, R.M. Thurman-Keup
    Fermilab, Batavia, USA
  
  Funding: Supported by Fermi Research Alliance, LLC under U.S. Dept. of Energy Contract No. DE-AC02-07CH11359, and Northern Illinois Univ. under US Dept. of Defense DURIP program Contract N00014-08-1-1064.
In this paper we demonstrate the generation of a tunable, longitudinal double-pulse electron beam. Experimental results on the generation of electron bunch trains with sub-picosecond structure have been previously reported where an initial transverse electron beam modulation was produced by masking the electron beam directly*. Here the initial transverse structure is imparted by masking of the photoinjector drive laser to effectively produce two horizontally offset beams at photoemission in the RF gun. A longitudinal double-pulse modulation is then realized after a transverse-to-longitudinal phase-space exchange beamline. Longitudinal profile tuning is demonstrated by upstream beam focusing in conjunction with downstream monitoring of single-shot electro-optic spectral decoding of coherent transition radiation.
* Y.-E. Sun et al., Tunable Subpicosecond Electron-Bunch-Train Generation Using a Transverse-To-Longitudinal Phase-Space Exchange Technique, Phys. Rev. Lett. 105, 234801 (2010). 		 
 
WEPPP056 Positron PWFA Simulations for FACET plasma, positron, simulation, electron 2834
 
  • S.J. Gessner, E. Adli, S. Corde, R.J. England, J.T. Frederico, M.J. Hogan, S.Z. Li, M.D. Litos, T.O. Raubenheimer, D.R. Walz, Z. Wu
    SLAC, Menlo Park, California, USA
  • W. An, W.B. Mori
    UCLA, Los Angeles, California, USA
  
  Funding: Work supported [optional: in part] by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
When a positron beam enters a plasma, plasma electrons are drawn in toward the beam axis, creating a region of extremely large charge density with complicated, nonlinear fields. Few analytic solutions exist to describe these fields, and this necessitates the use of simulations to model positron beam and plasma interactions. This presentation should cover recent work on positron PWFA simulations using the QuickPIC* particle-in-cell code. I will discuss the computational challenges associated with positron PWFA and specific applications of the simulations for future experimental tests at the FACET user facility at SLAC.
* C. Huang et al., "QuickPIC: A highly efficient particle-in-cell code for modeling wakefield acceleration in plasmas," J. Comp. Phys. 217, 658 (2006). 		 
 
WEPPR024 Motion of Charged Particle Dense Bunch in Nonuniform External Fields emittance, vacuum, resonance 2985
 
  • H.Y. Barminova
    ITEP, Moscow, Russia
  • A.S. Chikhachev
    Allrussian Electrotechnical Institute, Moskow, Russia
  
  At the output of a linear resonance accelerator, a charged particle beam consists of a bunch series, with the relation between bunch length and transverse bunch size changing widely. It is of importance to describe bunch dynamics in a selfconsistent manner*,** . Usually the charged bunch is described as ellipsoid with uniform density. Such description allows easy consideration of its own bunch fields. In the case of a nonstationary distribution it is difficult to build distribution function describing 3D-ellipsoid with uniform density** . In this paper such function is found for bunch formed as rotation ellipsoid. Radii ellipsoid equations are obtained for a bunch moving in nonuniform stationary external fields.
* A.S. Chikhachev. Kinetic theory of quasystationary state of charged particle beams. Moscow,2001.
** I.M. Kapchinsky. Theory of linear resonanse accelerators. Particle dynamics. Moscow,1982. 		 
 
WEPPR032 Simulation Studies of Adiabatic Thermal Beams in a Periodic Solenoidal Focusing Field simulation, emittance, vacuum, plasma 3003
 
  • C. Chen, T.J. Barton, D.M. Field, K.M. Lang
    MIT, Cambridge, Massachusetts, USA
  
  Funding: Research supported by DOE Grant No. DE-FG02-95ER40919, Grant No. DE-FG02-05ER54836, and MIT Undergraduate Research Opportunity Program.
Self-consistent simulations are performed to verify the theoretical predictions of adiabatic thermal beams in periodic solenoidal magnetic focusing fields*,**. In particular, results are obtained for adiabatic thermal beams that do not rotate in the Larmor frame. For such beams, the theoretical predictions of the rms beam envelope, the conservation of the rms thermal emittance, the adiabatic equation of state, and the Debye length are verified in the self-consistent simulations.
*K.R. Samokhvalova, J. Zhou and C. Chen, Phys. Plasma 14, 103102 (2007).
**J. Zhou, K.R. Samokhvalova and C. Chen, Phys. Plasma 15, 023102 (2008). 		 
 
WEPPR039 Nonlinear Lattice for Space-Charge Dominated Beam Transport with Suppressed Emittance Growth quadrupole, space-charge, emittance, lattice 3021
 
  • Y.K. Batygin, A. Scheinker
    LANL, Los Alamos, New Mexico, USA
  
  We present a feasible design for the implementation of a beam emittance growth suppressing lattice for space-charge dominated beams. Our analysis is based on original derivations developed in *. We present a FODO focusing channel with quadrupole and duodecapole components which on average create the field required to match the high-brightness beam with the structure. Matched beam exhibits smaller emittance growth than that in regular quadrupole focusing channel. Numerical results demonstrate the lattice’s performance in preventing halo formation of a nonuniform space charge dominated beam.
* Y. Batygin, Phys. Rev. E, 57, 5, p. 6020 (1998). 		 
 
WEPPR100 Short-Range Wakefields of Slowly Tapered Structures wakefield, cavity, factory, 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.  
 
THEPPB003 A 1 GeV CW FFAG High Intensity Proton Driver space-charge, emittance, simulation, cyclotron 3234
 
  • S.L. Sheehy
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • C. Johnstone
    Fermilab, Batavia, USA
  
  The drive for high beam power, high duty cycle, and reliable beams at reasonable cost has focused world attention on fixed-field accelerators, notably Fixed-Field Alternating Gradient accelerators (FFAGs). High-intensity GeV proton drivers are of particular interest, as these encounter duty cycle and space-charge limits in the synchrotron and machine size concerns in the weaker-focusing cyclotron. Recently, the concept of isochronous orbits has been explored and developed for non-scaling FFAGs using powerful new methodologies in FFAG accelerator design. These new breeds of FFAGs have been identified by international collaborations for serious study thanks to their potential applications including Accelerator Driven Subcritical Reactors (ADS) and Accelerator Transmutation of Waste. The extreme reliability requirements for ADS mandate CW operation capability and the FFAG’s strong focusing, particularly in the vertical, will serve to mitigate the effect of space charge (as compared with the weak-focusing cyclotron). This paper reports on these new advances in FFAG accelerator technology and presents a stable, 0.25-1GeV isochronous FFAG for an accelerator driven subcritical reactor.  
 
THPPC035 Final Assembly and Testing of the MICE Superconducting Spectrometer Solenoids solenoid, vacuum, radiation, instrumentation 3362
 
  • S.P. Virostek, M.A. Green, T.O. Niinikoski, H. Pan, S. Prestemon
    LBNL, Berkeley, California, USA
  • R. Preece
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  
  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 to demonstrate the principle of ionization cooling in a segment of a realistic cooling channel using a muon beam. The experiment is sited at Rutherford Appleton Laboratory in England. A 4-tesla uniform field region at each end of the cooling channel will be provided by a pair of identical, 3-m long spectrometer solenoids. As the beam enters and exits the cooling channel, the emittance will be measured within both the upstream and downstream 400 mm diameter magnet bores. Each magnet consists of a three-coil spectrometer magnet group and a two-coil pair that matches the solenoid uniform field into the adjacent MICE cooling channel. An array of five two-stage cryocoolers and one single-stage cryocooler are used to maintain the temperature of the magnet cold mass, radiation shield and current leads. Previous testing revealed several operational and design issues related to heat leak and quench protection that have since been corrected. Details of the magnet design modifications and their final assembly as well as the results of quench training tests will be presented here. 		 
 
THPPC055 Permanent Magnet Focusing System for Klystrons klystron, permanent-magnet, cathode, electron 3413
 
  • Y. Fuwa, Y. Iwashita, H. Tongu, S. Ushijima
    Kyoto ICR, Uji, Kyoto, Japan
  • S. Fukuda
    KEK, Ibaraki, Japan
  
  The Distributed RF System (DRFS) for ILC requires thousands of klystrons. The failure rate of the power supply for solenoid focusing coil of each klystron may be harmful to a regular operation of the ILC. In order to eliminate the power supplies and the cooling system for the coils, a permanent magnet beam focusing system is under development. It will help to reduce the power consumption as well. In our design, a unidirectional magnetic field configuration is adopted to eliminate the stop bands that arise from the periodic permanent magnet configuration. Since the required magnetic field is not high in this case, inexpensive anisotropic ferrite magnets can be used instead of magnets containing rare earth materials. On the basis of a half scaled model fabricated to evaluate the mechanical design, a full scaled model will be ready soon. In order to prove its feasibility, a power test of the klystron for DRFS with this magnet system is planned. The result of magnetic field distribution measurement and the power test will be presented.  
 
THPPP041 A CW High Charge State Heavy Ion RFQ Accelerator for SSC-LINAC Injector rfq, linac, resonance, ion 3826
 
  • G. Liu, J.E. Chen, S.L. Gao, Y.R. Lu, Z. Wang, X.Q. Yan, Q.F. Zhou, K. Zhu
    PKU/IHIP, Beijing, People's Republic of China
  • Y. He, C. Xiao, Y.Q. Yang, Y.J. Yuan, H.W. Zhao
    IMP, Lanzhou, People's Republic of China
  
  Funding: Supported by NSFC(11079001).
The cooler storage ring synchrotron CSR of HIRFL started running in 2008. The SFC (Sector Focusing Cyclotron) and SSC (Separator Sector Cyclotron) form an injector for the CSR. To improve beam intensity and/or injection efficiency, a new linear injector, the SSC-LINAC, for the SSC has been proposed to replace the existing SFC. The SSC-LINAC consists of an ECR ion source, LEBT, a RFQ, MEBT, and four IH-DTLs. This paper only represents the design research of the RFQ accelerator, which has a frequency of 53.667MHz. The ions up to uranium with ratio of mass-to-charge up to 7 are accelerated and injected into the CSR by the SSC-LINAC. The SSC-LINAC works on CW mode. The RFQ beam dynamic design study is based on 238U34+ beams with intensity of 0.5mA. The inter-vane voltage is 70kV with a maximum modulation factor of 1.93. It uses a 2.5m-long 4-rod structure to accelerate uranium ions from 3.728keV/u to 143keV/u with transmission efficiency of 94%. The RFQDYN code checks the transmission of different kinds of ions in the RFQ. The specific shunt impedance of RFQ is optimized to 438kΩ.m. The design of cavity tuning and the water cooling system are also included in this paper.
Corresponding authors: yrlu@pku.edu.cn, hey@impcas.ac.cn 		 
 
THPPP054 A New Half-Wave Resonator Cryomodule Design for Project-X cryomodule, cavity, alignment, vacuum 3865
 
  • Z.A. Conway, A.O. Bergado, R.L. Fischer, M. Kedzie, M.P. Kelly, B. Mustapha, P.N. Ostroumov
    ANL, Argonne, USA
  • V.A. Lebedev
    Fermilab, Batavia, USA
  
  Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics and Nuclear Physics, under Contract DE-AC02-76CH03000 and DE-AC02-06CH11357.
We present the current status of our Project-X half-wave resonator cryomodule development effort. The Project-X injector requires a single cryomodule with 9 superconducting, 162.5-MHz, β = 0.11, half-wave resonators interleaved with 6 integrated superconducting solenoids/steering coils. This cryomodule is being designed and build by ANL with the intent of delivering a device which has all external connections to the cryogenic, RF, and instrumentation systems located at removable junctions separated from the clean cavity vacuum system. Issues include the ease of assembly, cavity cleanliness, interfacing to subsystems (e.g., cryogenics, couplers, tuners, etc.), and satisfying the ANL/FNAL/DOE guidelines for vacuum vessels. We employ proven warm-to-cold low-particulate beamline transitions to minimize unused space along the linac, a top-loading box design that minimizes the size of the clean room assembly, and compact beamline devices to minimize the length of the focusing period. 		 
 
THPPP057 PXIE Optics and Layout cryomodule, rfq, cavity, solenoid 3871
 
  • V.A. Lebedev, S. Nagaitsev, J.-F. Ostiguy, A.V. Shemyakin, B.G. Shteynas, N. Solyak
    Fermilab, Batavia, USA
  
  The Project X Injector Experiment (PXIE) will serve as a prototype for the Project X front end. The aim is to validate the Project-X design and to decrease technical risks, known to be mainly related to the front end. PXIE will accelerate a 1 mA CW beam to about 25 MeV. It will consist of an ion source, LEBT, CW RFQ, MEBT, two SC cryomodules, a diagnostic section and a beam dump. A bunch-by-bunch chopper located in the MEBT section will allow formation of an arbitrary bunch structure. PXIE deviates somewhat from the current Project-X front end concept in that it provides additional instrumentation and relies on a reduced number of kickers for bunch chopping; the diagnostic section also include an RF separator to allow studying extinction of removed bunches. The paper discusses the main requirements and constraints motivating the facility layout and optics. Final adjustments to the Project X front end design, if needed, will be based on operational experience gained with PXIE.
Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. 		 
 
THPPP068 Investigation of a Multi-cell Cavity Structure Proposed for Improved Hydroforming cavity, coupling, HOM, SRF 3895
 
  • K.R. Shin
    ORNL RAD, Oak Ridge, Tennessee, USA
  • A.E. Fathy
    University of Tennessee, Knoxville, Tennessee, USA
  • J.A. Holmes, Y.W. Kang
    ORNL, Oak Ridge, Tennessee, USA
  
  A multi-cell cavity structure with rectangular coupling aperture between cavity cells is proposed. This investigation is to study the RF properties of such structure that may provide high yield in hydroforming. In mechanical point of view, the rectangular aperture iris may provide much improved structure quality in hydroforming since it can help to reduce the stress incurring within the sheet metal with improved structural malleability. The necking procedure can be easier because of greater perimeter in the iris geometry. Peak electric and magnetic fields per accelerating gradient may increase however, compared to traditional TESLA type elliptical cavity structure. The rectangular iris shape provides asymmetric transverse focusing per half RF period. If the horizontal and vertical rectangular irises are interleaved, the net transverse focusing may be achieved. 3D simulations with CST MWS have been carried out to analyze EM field properties and the cavity parameters.  
 
THPPP074 Chopping High Intensity Proton Beams Using a Pulsed Wien Filter proton, dipole, beam-transport, emittance 3907
 
  • C. Wiesner, L.P. Chau, H. Dinter, M. Droba, O. Meusel, I. Müller, D. Noll, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  Chopping high intensity beams at low energies poses substantial challenges. A novel ExB chopper system for proton beams of up to 200 mA at energies of 120 keV is being developed for the accelerator driven neutron source FRANZ*. It uses a Wien filter-type ExB configuration consisting of a static magnetic deflection field and a pulsed electric compensation field to deliver 100 ns beam pulses. The setup minimizes the risk of voltage breakdowns and provides secure beam dumping outside the transport line. In order to prevent beam aberrations and emittance growth careful matching of electric and magnetic deflection forces is required. Detailed numerical studies for the field design and their effects on beam transport were conducted. An H-type dipole magnet with special transverse and longitudinal pole contours was manufactured and combined with shielding tubes to shape the magnetic field. The electric field is driven by a HV pulse generator providing ±6 kV at a repetition rate of 250 kHz. Accurate layout of the deflector plates is required in order to tackle the issues of field quality, cooling and spark prevention. Transport simulations and beam deflection experiments are presented.
* U. Ratzinger et al., "The Driver Linac of the Neutron Source FRANZ," Proc. of IPAC2011, WEPS040, P. 2577 (2011). 		 
 
THPPR013 Beam Transport in Alternative Lattices at the University of Maryland Electron Ring (UMER) lattice, quadrupole, injection, betatron 3993
 
  • S. Bernal, B.L. Beaudoin, M. Cornacchia, R.A. Kishek, D.F. Sutter
    UMD, College Park, Maryland, USA
  
  Funding: This work is funded by the US Dept. of Energy Offices of High Energy Physics and High Energy Density Physics, and by the US Dept. of Defense Office of Naval Research and Joint Technology Office.
We discuss the motivation, general procedure and results of first experiments of beam transport with two alternative focusing schemes at UMER, a low-energy (10 keV), high-current (1-100 mA) electron storage ring. The new ring optics simplifies injection and RMS envelope matching, and gives us a larger number of beam position monitors (BPMs) per (un-depressed) betatron wavelength, all of which are desirable conditions for better orbit control. Furthermore, one of the new optics schemes is more symmetrical than the standard one, facilitating e.g. the implementation of quadrupole scans for betatron resonance studies. The alternative lattices also allow us to expand significantly on the tune parameter space available for the study of space-charge dominated beam transport. 		 
 
THPPR043 Applications of X-band 950 keV and 3.95 MeV Linac X-ray Source for On-site Inspection linac, radiation, coupling, shielding 4071
 
  • M. Uesaka, K. Demachi, K. Dobashi, T. Fujiwara, H.F. Jin, M. Jin, H. Zhu
    The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
  • Y. Hattori
    Hitachi Engineering & Services Co.,Ltd., Japan
  • J. Kusano, N. Nakamura, M. Yamamoto
    Accuthera Inc., Kawasaki, Kanagawa, Japan
  • I. Miura
    Mitsubishi Chemical Corporation, Japan
  • E. Tanabe
    AET, Kawasaki-City, Japan
  
  Our portable X-band (9.3GHz) 950KeV linac has been successfully upgraded. The problems of RF power oscillation, beam current oscillation and reduction and finally lack of X-ray intensity were solved by replacing the axial coupling cavities with the side-coupled ones. Designed X-ray dose rate of 0.05 Sv/min@1m is going to be achieved. X-ray source part with the local radiation shielding is connected by the flexible waveguide with the box of a 250 kW magnetron and a cooling unit. The total system consists of the three suit-case-size units, the last of which is one for the electric power supply. We have also developed a portable X-band (9.3GHz) 3.95MeV linac for on-site bridge inspection. The system consists of a 62kg X-ray source part without 80kg target collimator, a 62kg RF power source and other utility box of 116kg. Designed X-ray dose rate is 2 Sv/min@1m with 200pps repetition rate and we have achieved 0.5 Sv/min@1m with 50pps repetition rate. Demonstration of the measurement of wall thinning of metal pipes with thick thermal shielding by 950keV linac and degradation of reinforced concrete sample by 3.95MeV is under way. Updated measurement results will be presented.