Accelerator Technology


Paper Title Page
WPAE007 Commissioning of the LNLS 2 T Hybrid Wiggler 1072
  • R.H.A. Farias, J.F. Citadini, M.J. Ferreira, J.G.R.S. Franco, A.F.A. Gouveia, L.C. Jahnel, L. Liu, R.T. Neuenschwander, X.R. Resende, P.F. Tavares, G. Tosin
    LNLS, Campinas
  • N.P. Abreu
    UNICAMP, Campinas, São Paulo
  Funding: MCT-CNPq, FAPESP.

We present the results of the commissioning of a 28-pole 2 T Hybrid Wiggler at the 1.37 GeV electron storage ring of the Brazilian Synchrotron Light Source. The wiggler will be used mainly for protein crystallography and was optimized for the production of 12 keV photons. The very high field and relatively large gap (22 mm) of this insertion device led to a magnetic design that includes large main and side magnets and heavily saturated poles. We present the results of the commissioning with beam, with special attention to the correction of the large linear tune-shift perturbations produced by the wiggler as well as on the reduction of beam lifetime at full energy. Since the injection at the LNLS storage ring is performed at 500 MeV we also focus on the effects of non-linearities and their impact on injection efficiency.

WPAE008 Redesign of a Low Energy Probe Head 1105
  • Y.-N. Rao, G.H. Mackenzie, T.C. Ries
    TRIUMF, Vancouver
  The present situation of the low energy probe L·102 in TRIUMF cyctron is that the thickness of finger 5 is uniform in the radial direction and its weight which amounts to ~447 g is affecting its re-circulating ball mechanism and causing it to fall below the median plane over its range of movement (13.890 to 161.515 inch). We first made simulations to determine the optimum thickness of the probe head vs the radial length so as to reduce its weight. And then, we compared the simulation results with experimental measurements made. Finally, we calculated the temperature rise caused by the beam power dumped on the probe, and figured out the maximum beam current that can be dumped on the finger.  
WPAE010 Neutron Flux and Activation Calculations for a High Current Deuteron Accelerator 1192
  • A. Coniglio, M.P. Pillon, S. Sandri
    ENEA C.R. Frascati, Frascati (Roma)
  • M. D'Arienzo
    CNR/RFX, Padova
  Neutron analysis of the first Neutral Beam (NB) for the International Thermonuclear Experimental Reactor (ITER) was performed to provide the basis for the study of the following main aspects: personnel safety during normal operation and maintenance, radiation shielding design, transportability of the NB components in the European countries. The first ITER NB is a medium energy light particle accelerator. In the scenario considered for the calculation the accelerated particles are negative deuterium ions with maximum energy of 1 MeV. The average beam current is 13.3 A. To assess neutron transport in the ITER NB structure a mathematical model of the components geometry was implemented into MCNP computer code (MCNP version 4c2. "Monte Carlo N-Particle Transport Code System." RSICC Computer Code Collection. June 2001). The neutron source definition was outlined considering both D-D and D-T neutron production. FISPACT code (R.A. Forrest, FISPACT-2003. EURATOM/UKAEA Fusion, December 2002) was used to assess neutron activation in the material of the system components. Radioactive inventory and contact dose rate were assessed considering the potential operative scenarios.  
WPAE011 Electrostatic Deflectors: New Design for High Intensity Beam Extraction 1245
  • S. Passarello, G. Cuttone, G. Gallo, D. Garufi, A. Grmek, G. Manno, M. Re, E. ZappalÃ
    INFN/LNS, Catania
  Funding: INFN-LNS Catania

During the last years big effort was devoted to increase the electrostatic deflectors’ reliability; this provided a better comprehension of the most significant effects concerning their working conditions. Deflectors were checked during the normal operation of the K800 Superconducting Cyclotron (CS) at LNS, at the operating pressure of 1 10-6 mbar and a magnetic field of 3.5 T, the maximum cathodes voltage was –60kV (120 kV/cm). The maximum extracted beam power was, up to now, 100 W; it is foreseen to extract up to 500 W. In this contribution we present the study, the tests and the design of a new water cooled electrostatic deflector. Particular effort was applied to optimise the beam extraction efficiency, the thermal dissipation, and the mechanical stability. In particularly we implemented new insulators, new anodised aluminium cathodes, new Ta septum, new voltage and water feedthroughs and a more efficient cooling system. All these improvements were performed to increase the mean time between failure and the beam current stability.

WPAE012 Gamma-Ray Irradiation Experiments of Collimator Key Components for the 3GeV-RCS of J-PARC 1309
  • M. Kinsho, F. Masukawa, N. Ogiwara, O. Takeda, K. Yamamoto
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • J. Kusano
    Japan Atomic Energy Institute, Linac Laboratory, Tokai-Mura
  The turbo molecular pump and the stepping motor which can be operated exposed to high radiation has been under development at JAERI for use in the 3GeV-RCS of the J-PARC. In order to determine the extent of radiation damage to those instruments, gamma-ray irradiation testing was performed at JAERI. It was succeed that the turbo molecular pump and stepping motor could operate properly when given an absorption dose more than 15 MGy in a gamma-ray irradiation environment.  
WPAE013 Development of the Collimator System for the 3GEV Rapid Cycling Synchrotron 1365
  • K. Yamamoto
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • M. Kinsho
    Japan Atomic Energy Institute, Linac Laboratory, Tokai-Mura
  In order to localize the beam loss in the restricted area, the beam collimation system is prepared in the 3GeV Rapid Cycling Synchrotron (RCS) of the Japan Proton Accelerator Complex (J-PARC) Project. The amount of the localized beam loss on the one collimator is estimated about 1.2kW, and that loss generates a large quantity of the secondary radiations. So the beam collimator must be designed that it is covered with enough shielding. We calculated the radiation level of the collimator and decided necessary shielding thickness. This result indicated that the residual dose rate at the outside surface of the shielding is mostly under 1mSv/h. We developed the remote cramp system and rad-hard components in order to reduce the radiation exposure during maintenance of the collimator. And also we coated Titanium Nitride (TiN) film on the inside surface of the vacuum chamber in order to reduce the secondary electron emission from the collimator and chamber surface. Now we investigate the possibility of another coating.  
WPAE014 Conceptual Design of a Longitudinal Halo Collimator for J-PARC Linac 1413
  • M. Ikegami
    KEK, Ibaraki
  • T. Ohkawa
    JAERI, Ibaraki-ken
  In a high-intensity proton accelerator, avoidance of excess beam loss is essentially important to enable hands-on maintenance. To reduce the uncontrolled beam loss in the following ring, we plan to install a longitudinal halo collimator system in a beam transport line after the injector linac. The collimator system is supposed to have two main roles: One is the elimination of longitudinal tail or halo particles destined to be lost in the following ring, and the other is the removal of anomalous beams which can be resulted from, for example, RF discharge of an accelerating cavity. We plan to adopt a "periodic collimation scheme" in the collimator system taking advantage of the three-fold symmetry of the arc section. The momentum aperture of the collimator system is expected to be reduced by the factor of two adopting periodic collimation. In this paper, conceptual design of the collimator system is presented together with the results of particle simulations.  
WPAE015 High Heat-Load Slits for the PLS Multipole Wiggler 1449
  • K.H. Gil, J.Y. Choi, C.W. Chung, Y.-C. Kim, H.-S. Lee
    PAL, Pohang, Kyungbuk
  The HFMX (High Flux Macromolecular X-ray crystallography) beamline under commissioning at Pohang Accelerator Laboratory uses beam from a multipole wiggler for MAD experiment. Two horizontal and vertical slits relevant to high heat load are installed at its front-end. In order to treat high heat load and to reduce beam scattering, the horizontal slit has two glidcop blocks with 10° of vertical inclination and its tungsten blades defining beam size are bolted on backsides of both blocks. The blocks of the slit are adjusted on fixed slides by two actuating bars, respectively. Water through channels machined along the actuating bars cool down the heat load of both blocks. The vertical slit has the same structure as the horizontal slit except its installation direction and angle of vertical inclination. The installed slits show stable operation performance and no alignment for the blocks is required by virtue of a pair of blocks translating on slides. The cooling performance of two slits is also shown to be acceptable. In this article, the details of the design and manufacture of the two slits are presented and its operation performance is reported.  
WPAE016 Development of a Precision Amplifier for the Detector 1514
  • K.-H. Park, C.W. Chung, S.-M. Hong, S.-H. Jeong, Y.G. Jung, D.E. Kim, H.-S. Lee, W.W. Lee
    PAL, Pohang, Kyungbuk
  • B.-K. Kang
    POSTECH, Pohang, Kyungbuk
  A high gain trans-resistance amplfier has been developed for measuring the intensity of synchrotron radiation at Pohang Light Source(PLS). This amplifier built with discrete elements and operational amplifiers.It had the capability of measuring range from 1pA to 1 uA with good linearity. A microprocessor was also installed to interface the amplifier with the computer, and controlled the other sub-circuits. The various characteristics of amplifier such as linearity, sensitivity,stability, etc. have been investigated, and its experimental results carried out at the beam line are presented in this paper.  
WPAE017 Installation of the LHC Long Straight Sections (LSS) 1563
  • S. Bartolome-Jimenez, G. Trinquart
    CERN, Geneva
  The LHC long straight sections (LSS) serve as experimental or utility insertions. There are two high luminosity experimental insertions located at points 1 and 5 and two more experimental insertions at points 2 and 8 which also contain the injection systems. The beams only cross at these four locations and are focused by superconducting low-beta triplets. Insertions 3 and 7 each contain two collimation systems. Insertion 4 contains two RF systems. Insertion 6 contains the beam dumping system. The installation of the LSS is a challenge due to the compact layout that characterises these areas and the difficulties related to the underground work mainly in zones of restricted access. Specific devices are required for handling and installing various heavy and voluminous elements. This paper reviews the installation scenarios, describes the sequences presently planned and highlights the potential problem areas. The particular case of sector 7-8 where the LSS elements will be installed in parallel with the cryogenic distribution line (QRL) is used as an example of a ‘rapid’ installation scheme to illustrate how resources are used. The consequences of possible shortcuts are also mentioned.  
WPAE018 Performance Tests of Survey Instruments Used in Radiation Fields Around High-Energy Accelerators 1595
  • S. Mayer, D. Forkel-Wirth, M. Fuerstner, H.G. Menzel, S. Roesler, C. Theis, H. Vincke
    CERN, Geneva
  Measurements of ambient dose equivalent in stray radiation fields behind the shielding of high-energy accelerators are a challenging task. Several radiation components (photons, neutrons, charged particles), spanning a wide range of energies, contribute to the total dose equivalent. In routine-measurements, the total dose equivalent is obtained by the combination of several radiation detectors. Ionisation chambers, which are sensitive to all radiation components, are employed together with so-called REM counters, which are responding mainly to neutrons. The total dose equivalent is correctly assessed provided that the response is interpreted carefully by using appropriate corrections and calibration factors. For this reason measurements were carried out in a high-energy reference field at CERN, which allows one to study the response of the different detectors in a mixed radiation field under controlled conditions. In addition, the field was simulated by Monte Carlo simulations. The outcome of these studies serves on one hand as a basis for quality assurance and improves on the other hand the knowledge of the instrument’s response for future applications at the LHC.  
WPAE019 How to Fill a Narrow 27 km Long Tube with a Huge Number of Accelerator Components? 1634
  • Y. Muttoni, J.-P. Corso, R. V. Valbuena
    CERN, Geneva
  As in large scale industrial projects, research projects, such as giant and complex particle accelerators, require intensive spatial integration studies using 3D CAD models, from the design to the installation phases. The future management of the LHC machine configuration during its operation will rely on the quality of the information, produced during these studies.This paper presents the powerful data-processing tools used in the project to ensure the spatial integration of several thousand different components in the limited space available.It describes how the documentation and information generated have been made available to a great number of users through a dedicated Web site and how installation nonconformities were handled.  
WPAE020 A Large Diameter Entrance Window for the LHC Beam Dump Line 1698
  • A. Presland, B. Goddard, J.M. Jimenez, D.R. Ramos, R. Veness
    CERN, Geneva
  The graphite LHC beam dump block TDE has to absorb the full LHC beam intensity at 7 TeV. The TDE vessel will be filled with inert gas at atmospheric pressure, and requires a large diameter entrance window for vacuum separation from the beam dumping transfer line. The swept LHC beam must traverse this window without damage for regular operation of the beam dump dilution system. For dilution failures, the entrance window must survive most of the accident cases, and must not fail catastrophically in the event of damage. The conceptual design of the entrance window is presented, together with the load conditions and performance criteria. The FLUKA energy deposition simulations and ANSYS stress calculations are described, and the results discussed.  
WPAE021 Short Straight Sections in the LHC Matching Sections (MS SSS): An Extension of the Arc Cryostats To Fulfill Specific Machine Functionalities 1724
  • V. Parma, H. Prin
    CERN, Geneva
  • fl. Lutton
    IPN, Orsay
  Funding: IPN-CNRS, 15 rue Georges Clémenceau 91406 ORSAY, France.

The LHC insertions require 50 specific superconducting quadrupoles, operating in boiling helium at 4.5 K and housed in individual cryostats to form the MS Short Straight Sections (MS SSS). The quadrupoles and corrector magnets are assembled in 8 families of cold masses, with lengths ranging from 5 to 11 m and weights ranging from 60 to 140 kN. The MS SSS need to fulfil specific requirements related to the collider topology, its cryogenic layout and the powering scheme. Most MS SSS are standalone cryogenic and super-conducting units, i.e. they are not in the continuous arc cryostat, and therefore need dedicated cryogenic and electrical feeding. Specially designed cryostat end-caps are required to close the vacuum vessels at each end, which include low heat in-leak Cold-to-Warm transitions (CWT) for the beam tubes and 6 kA local electrical feedthrough for powering the quadrupoles. This paper presents the design of the MS SSS cryostats as an extension of the arc cryostat’s design to achieve a standard and consequently cost-effective solution, and the design solutions chosen to satisfy their specific functionalities.

WPAE022 Progress on the Liquid Hydrogen Absorber for the MICE Cooling Channel 1772
  • M.A.C. Cummings
    Northern Illinois University, DeKalb, Illinois
  • S. Ishimoto
    KEK, Ibaraki
  This report describes the progress made on the design of the liquid hydrogen absorber for the international Muon Ionization Cooling Experiment (MICE). The absorber consists of a 21-liter vessel that contains liquid hydrogen (1.5 kg) or liquid helium (2.63 kg). The cryogen vessel is within the warm bore of the superconducting focusing magnet for the MICE. The purpose of the magnet is to provide a low beam beta region within the absorber. For safety reasons, the vacuum vessel for the hydrogen absorber is separated from the vacuum vessel for the superconducting magnet and the vacuum that surrounds the RF cavities or the detector. The absorber has two 300 mm-diameter thin aluminum windows. The vacuum vessel around the absorber has a pair of thin aluminum windows that separate the absorber vacuum space from adjacent vacuum spaces. The absorber will be cooled down using a heat exchanger that is built into the absorber walls. Liquid nitrogen is used to cool the absorber to 80 K. Liquid helium completes the absorber cool down and condenses hydrogen in the absorber. The absorber may also be filled with liquid helium to measure muon cooling in helium.  
WPAE025 Design for a 1.3 MW, 13 MeV Beam Dump for an Energy Recovery Linac 1877
  • C.K. Sinclair
    Cornell University, Department of Physics, Ithaca, New York
  • Y. He, C.H. Smith
    Cornell University, Ithaca, New York
  Funding: Work supported by Cornell University.

The electron beam exiting an Energy Recovery Linac (ERL) is dumped close to the injection energy. This energy is chosen as low as possible while allowing the beam quality specifications to be met. As ERLs are designed for high average beam current, beam dumps are required to handle high beam power at low energy. Low energy electrons have a short range in practical dump materials, requiring the beam size at the dump face be enlarged to give acceptable power densities and heat fluxes. Cornell University is developing a 100 mA average current ERL as a synchrotron radiation source. The 13 MeV optimum injection energy requires a 1.3 MW beam dump. We present a mature design for this dump, using an array of water-cooled extruded copper tubes. This array is mounted in the accelerator vacuum normal to the beam. Fatigue failure resulting from abrupt thermal cycles associated with beam trips is a potential failure mechanism. We report on designs for a 75 kW, 750 keV tube-cooled beryllium plate dump for electron gun testing, and a 500 kW, 5 to 15 MeV copper tube dump for use with the prototype injector under development. We expect to test the beryllium dump within a year, and the higher power copper dump within 2-1/2 years.

WPAE027 Magnetic Shielding of an Electron Beamline in a Hadron Accelerator Enclosure 1997
  • T.K. Kroc, C.W. Schmidt, A.V. Shemyakin
    Fermilab, Batavia, Illinois
  Funding: *Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy.

The Fermilab Electron Cooling Project requires the operation of a 4.35 MeV electron beam in the same enclosure that houses the 120 – 150 GeV Main Injector. Effective shielding of the magnetic fields from the ramped electrical buses and local static fields is necessary to maintain the high beam quality and recirculation efficiency required by the electron cooling system. This paper discusses the operational tolerances and the design of the beamline shielding, bus design, and bus shielding as well as experimental results from the prototype and final installation.

WPAE028 Radiation Issues in the Fermilab Booster Magnets 2041
  • E. Prebys
    Fermilab, Batavia, Illinois
  Funding: Department of Energy.

The demands of the Fermilab neutrino program will require the 30 year old Fermilab 8 GeV Booster to deliver higher intensities than it ever has. Total proton throughput is limited by radiation damage and activation due to beam loss in the Booster tunnel. Of particular concern is the insulation in the 96 combined function lattice magnets. This poster describes a study of the potential radiation damage to these magnets from extended running at the planned intensities.

WPAE029 Tevatron Beam-beam Compensation Project Progress 2083
  • V.D. Shiltsev, R.J. Hively, V. Kamerdzhiev, A. Klebaner, G.F. Kuznetsov, A. Martinez, H. Pfeffer, G.W. Saewert, A. Semenov, D. Wolff, X. Zhang
    Fermilab, Batavia, Illinois
  • K. Bishofberger
    UCLA, Los Angeles, California
  • I. Bogdanov, E. Kashtanov, S. Kozub, V. Sytnik, L. Tkachenko
    IHEP Protvino, Protvino, Moscow Region
  • A.V. Kuzmin, M.A. Tiunov
    BINP SB RAS, Novosibirsk
  • F. Zimmermann
    CERN, Geneva
  Funding: Work supported by the Universities Research Assos., Inc., under contract DE-AC02-76CH03000 with the U.S. Dept. of Energy.

The 2nd Tevatron electron lens (TEL2) is under the final phase of development and prepare for the installation in the Tevatron. In this report, we will describe the system and the main upgrades from the TEL1. We will also show the magnetic field measurement results, beam testing and plan for installation. The special operation consideration of the TEL2 under high radiation dose will also be discussed.

WPAE030 Thermal Analysis of the Al Window for a New CESR-c Luminosity Monitor 2137
  • Y. He, D.H. Rice
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • Y. Li, M.A. Palmer
    Cornell University, Department of Physics, Ithaca, New York
  Funding: Work supported by the U.S. National Science Foundation.

A luminosity monitor using photons from radiative bhabha events at the CLEO interaction point (IP) has been installed in the Cornell Electron Storage Ring (CESR). A key vacuum and detector component is the photon window/converter whose uniformity and thickness are critical for determining the resolution of the total energy deposited in the segmented luminosity monitor. The window design must accommodate the operational requirements of the new monitor at CLEO-c beam energies of 1.5-2.5 GeV and also provide sufficient safety margin for operation at 5.3 GeV beam energies for Cornell High Energy Synchrotron Source (CHESS) running. During 5.3 GeV operation, intense stripes of synchrotron radiation from the interaction region superconducting quadrupole magnets as well as nearby bending magnets strike the window. During the course of window development, several materials and designs were evaluated. Thermal stresses were calculated using the finite element code ANSYS for various beam conditions to guide the cooling design. A window using aluminum alloy (6061-T6) was ultimately chosen to provide optimal performance for both CLEO-c and CHESS running conditions. The window has been in successful operation since September 2004.

WPAE031 Mechanical Design of a Heavy Ion Beam Dump for the RIA Fragmentation Line 2185
  • W. Stein, L. Ahle
    LLNL, Livermore, California
  • D.L. Conner
    ORNL, Oak Ridge, Tennessee
  The RIA fragmentation line requires a beam stop for the primary beam downstream of the first dipole magnet. The beam may consist of U, Ca, Sn, Kr, or O ions. with a variety of power densities. The configuration with highest power density is for the U beam, with a spot size of 3 cm x 3 cm and a total power of up to 300 kW. The mechanical design of the dump that meets these criteria consists of a 50 cm diameter aluminum wheel with water coolant channels. A hollow drive shaft supplies the coolant water and connects the wheel to an electrical motor located in an air space in the floor above the dump. The beam strikes the wheel along the outer perimeter and passes through a thin window of aluminum where 10% of its power is absorbed and the remainder of the beam is absorbed in flowing water behind the window. Rotation of the wheel at 400 RPM results in maximum aluminum temperatures below 100 C and acceptably low thermal stresses of 5 ksi. Rotating the wheel also results in low radiation damage levels by spreading the damage out over the whole perimeter of the wheel. For some of the other beams, a stationary dump consisting of a thin aluminum window with water acting as a coolant and absorber appears to be feasible.  
WPAE034 Fast Neutron Damage Studies on NdFeB Materials 2351
  • J.E. Spencer, S.D. Anderson, R. Wolf
    SLAC, Menlo Park, California
  • A. Baldwin, D.E. Pellet
    UCD, Davis, California
  • M. Boussoufi
    UCD/MNRC, McClellan, California
  • J.T. Volk
    Fermilab, Batavia, Illinois
  Funding: Support of this work was under U.S. Dept. of Energy contracts DE-AC02-76SF00515, DE-AC02-76CH03000 and LCRD contract DE-FG02-03ER41280.

Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) where the accelerator and detectors will be subjected to large fluences of hadrons, leptons and gammas over the life of the facility. Although the linacs will be superconducting, there are still many potential uses for NdFeB in the damping rings, injection and extraction lines and final focus. Our understanding of the radiation damage situation for rare earth permanent magnet materials was presented at PAC2003 and our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were presented at EPAC2004 where the damage appeared proportional to the distances between the effective operating points and Hc. Here we have extended those doses and included more commercial samples together with the induced radioactivities associated with their respective dopants. Hall probe data for the external induction distributions are compared with vector magnetization measurements for the different materials.

WPAE035 SNS Ring Injection Stripped Electron Collection: Design Analysis and Technical Issues 2384
  • Y.Y. Lee, G.J. Mahler, W. Meng, D. Raparia, L. Wang, J. Wei
    BNL, Upton, Long Island, New York
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

This paper describes the simulation studies on the motions of stripped electrons generated in the injection section of the Spallation Neutron Source (SNS) accumulator ring and the effective collection mechanism. Such studies are important for high intensity machines, in order to reduce beam loss and protect other components in the vicinity. The magnetic field is applied to guide electrons to a collector, which is located at the bottom of the beam chamber. Part of the study results with and without considering the interactions between electrons and materials are presented and discussed. The final engineering design of the electron collector (catcher) is also presented and described.

WPAE036 Harmonic Analysis of Linac Alignment 2431
  • R.C. McCrady
    LANL, Los Alamos, New Mexico
  Funding: Work conducted at Los Alamos National Laboratory, which is operated by the University of California for the United States Department of Energy under contract W-7405-ENG-36.

We have analyzed the requirements on alignment of the focusing elements (quadrupole doublets) in the Los Alamos Neutron Science Center (LANSCE) side coupled linac. The analysis is performed in terms of harmonics of the quardrupole spacing. This allows us to determine the effect of intentional deviations from a straight line, such as following the curvature of the Earth, and of unintentional deviations introduced by measurement and alignment errors. Results are compared to measured positions of the doublets.

WPAE037 Deformation Monitoring of the Spallation Neutron Source (SNS) Tunnels 2509
  • J.J. Error, D.R. Bruce, J.J. Fazekas, S.A. Helus, J.R. Maines
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

The SNS Project is a 1.4 MW accelerator-based neutron source located at Oak Ridge National Laboratory in Oak Ridge, Tennessee. For shielding purposes, a 17 foot berm of native soil has been constructed on top of the accelerator tunnel system. This backfill has caused ongoing settlement of the tunnels. The settlement has been monitored by the SNS Survey and Alignment Group at regular intervals, in order to discover the patterns of deformation, and to determine when the tunnels will be stable enough for precise alignment of beam line components. The latest monitoring results indicate that the settlement rate has significantly decreased. This paper discusses the techniques and instrumentation of the monitoring surveys, and provides an analysis of the results.

WPAE038 Resonance Control Cooling System Performance and Developments 2541
  • P.E. Gibson, A.V. Aleksandrov, M.M. Champion, G.W. Dodson, J.P. Schubert, J.Y. Tang
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built at Oak Ridge National Laboratory. The warm linac portion, designed by Los Alamos, has been installed and commissioned. The warm linac is comprised of six Drift Tube Linac (DTL) tanks and four Coupled Cavity Linac (CCL) modules. For commissioning purposes the accelerating systems have been operated at less than the design 6% duty factor. During lower power operation there is less RF cavity heating. This decrease in heat load causes operational stability issues for the associated Resonance Control Cooling Systems (RCCSs) which were designed for full duty factor operation. To understand this effect operational results have been analyzed and tests have been performed. External system factors have been explored and the resulting impacts defined. Dynamic modeling of the systems has been done via a collaboration with the Institute for Nuclear Research (INR), Moscow, Russia. New RCCS operation code has been implemented. Increases in system performance achieved and solutions employed will be presented.

WPAE039 Optical Tooling and its Uses at the Spallation Neutron Source (SNS) 2577
  • S.A. Helus, D.R. Bruce, J.J. Error, J.J. Fazekas, J.R. Maines
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

Optical tooling has been a mainstay of the accelerator alignment community for decades. Even now in the age of electronic survey equipment, optical tooling remains a viable alternative, and at times the only alternative. At SNS, we combine traditional optical tooling alignment methods, instrumentation, and techniques, with the more modern electronic techniques. This paper deals with the integration of optical tooling into the electronic survey world.

WPAE040 Comparison of Techniques for Longitudinal Tuning of the SNS Drift Tube Linac 2616
  • D.-O. Jeon
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

It is important to bring the cavity field amplitude and phase to the design values for a high intensity linac such as the Spallation Neutron Source (SNS)linac. A few techniques are available, such as the longitudinal acceptance scan and phase scan. During SNS linac commissioning, tuning of cavities was conducted using the acceptance scan and phase scan technique based on multiparticle simulations. The two techniques are compared.

WPAE041 Development of a New Beam Diagnostics Platform 2669
  • R.T. Roseberry, S. Assadi, G.R. Murdoch
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

The Spallation Neutron Source Project (SNS) is an accelerator-based neutron source currently under construction at Oak Ridge National Laboratory (ORNL). The availability of space along completed portions of the accelerator for the addition of beam diagnostic is limited. A new platform for mounting a variety of instruments has been created by replacing part of the Medium Energy Beam Transport (MEBT) section of the accelerator developed by Lawrence Berkeley National Laboratory. The design and current capabilities of this instrument platform will be presented along with plans for future enhancements.

WPAE042 Beam Loss and Residual Activation Trending 2726
  • G.W. Dodson, M. Giannella, A.T. Ruffin, T.L. Williams
    ORNL, Oak Ridge, Tennessee
  Funding: This work was supported by SNS through UT-Batelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. The SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

The SNS Front End, Drift Tube Linac and most of the Coupled Cavity Linac have been operated during commissioning. Beam loss data were taken with differential Beam Current Monitors, and Beam loss Monitors during commissioning. Residual activation data were taken at various times during and after the run. An analysis of beam loss trending, beam loss monitor data and residual activation will be shown.

WPAE043 Alignment of the Booster Injector for the Duke Free Electron Laser Storage Ring 2786
  • M. Emamian, M.D. Busch, S. Mikhailov
    DU/FEL, Durham, North Carolina
  • N. Gavrilov
    BINP SB RAS, Novosibirsk
  Funding: This work is supported by U.S. Department of Energy grant DE-FG02-01ER41175 and by U.S. AFOSR MFEL grant F49620-001-0370.

This paper presents the methodology and initial results for mechanical alignment of the booster synchrotron for the Duke FEL storage ring. The booster is a compact design and requires special considerations for alignment. The magnetic and vacuum elements of the arcs have been designed for alignment by a laser tracker system. A parametric 3D design package has been used to determine target coordinates. These target coordinates evolve from design goals to physically verified dimensions by modifying the parametric model to match mechanical measurement data after fabrication. By utilizing the functionality of the laser tracker system and a parametric 3D modeler, a direct and efficient measurement and alignment technique has been developed for a complex geometry.

WPAE044 An Alignment of J-PARC Linac 2851
  • T. Morishita, H. Ao, T. Ito, A. Ueno
    JAERI/LINAC, Ibaraki-ken
  • K. Hasegawa
    JAERI, Ibaraki-ken
  • M. Ikegami, C. Kubota, F. Naito, E. Takasaki, H. Tanaka, K. Yoshino
    KEK, Ibaraki
  J-PARC linear accelerator components are now being installed in the accelerator tunnel, whose total length is more than 400 m including the beam transport line to RCS (Rapid Cycling Synchrotron). A precise alignment of accelerator components is essential for a high quality beam acceleration. In this paper, planned alignment schemes for the installation of linac components, the fine alignment before beam acceleration, and watching the long term motion of the building are described. Guide points are placed on the floor, which acts as a reference for the initial alignment at the installation and also as a relay point for the long surveying network linking at the fine alignment. For a straight line alignment, the wire position sensor is placed on the offset position with respect to the beam center by a target holder, then a single wire can cover the accelerator cavities and the focusing magnets at the DTL-SDTL section (120m). The hydrostatic levering system (HLS) is used for watching the floor elevation (changes) over the long period.  
WPAE045 Progress on RF Coupling Coil Module Design for the MICE Channel 2869
  • D. Li, M.A. Green, S.P. Virostek, M.S. Zisman
    LBNL, Berkeley, California
  • W. Lau, A. E. White, S.Q. Yang
    OXFORDphysics, Oxford, Oxon
  Funding: This research work is supported by the US Department of Energy, under Contract No. DE-AC03-76SF00098.

We describe the progress on the design of the RF coupling coil (RFCC) module for the international Muon Ionization Cooling Experiment (MICE) at Rutherford Appleton Laboratory (RAL) in the UK. The MICE cooling channel design consists of two SFOFO cells that is similar to that of the US Study-II of a neutrino factory. The MICE RFCC module comprises a superconducting solenoid, mounted around four normal conducting 201.25-MHz RF cavities. Each cavity has a pair of thin curved beryllium windows to close the conventional open beam irises, so thatnecessitating separate power feeds for each of the four cavities has to be separately powered. The coil package that surrounds the RF cavities sits is mounted on a vacuum vessel. The RF vacuum is shared between the cavities and the vacuum vessel around the cavities such that. Therefore there is no differential pressure on the thin beryllium windows. This paper discusses the design progress of the RFCC module, the fabrication progress of a prototype 201.25-MHz cavity, and the superconducting coupling coil that will be cooled using a single, small 4 K cooler.

WPAE046 Diffusion Brazing and Welding of the Accelerating Structure 2938
  • V.S. Avagyan
    CANDLE, Yerevan
  Funding: This work has been performed in Yerevan Physics Institute and the Institute of Electrowelding E.O. Paton, the Ukraine.

This work presents technologies of copper accelarating structure diffusion joints. The formation conditions of copper diffusion joint with minimal residual plastic strain are determined experimentally.

WPAE050 First Calibrations of Alanine and Radio-Photo-Luminescence Dosemeters to a Hadronic Radiation Environment 3097
  • M. Fuerstner, I. Brunner, D. Forkel-Wirth, S. Mayer, H.G. Menzel, H. Vincke
    CERN, Geneva
  • I. Floret
    Ecole d'ingénieurs de Genève, Genève
  Alanine and Radio-Photo-Luminescence (RPL) dosimeters are used to monitor radiation doses occurring inside the tunnels of all CERN accelerators including the Large Hadron Collider (LHC). They are placed close to radiation sensitive machine components like cables or insulation of magnet coils to predict their remaining lifetime. The dosimeters are exposed to mixed high-energy radiation fields. However, up to now both dosimeter types are calibrated to 60Co-photons only. In order to study the response of RPL and alanine dosimeters to mixed particle fields like those occurring at CERN’s accelerators, an irradiation campaign at the CERN-EC High-Energy Reference field Facility (CERF-field) was performed. Moreover, the dosimeters were first time calibrated to a proton radiation field of a constant momentum of 24 GeV/c. In addition to the experiment FLUKA Monte Carlo simulations were carried out, which provide information concerning the energy deposition and the radiation field at the dosimeter locations.  
WPAE053 Neutronics Assessments for a RIA Fragmentation Line Beam Dump Concept 3227
  • J.L. Boles, L. Ahle, S. Reyes, W. Stein
    LLNL, Livermore, California
  Funding: Work performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

Heavy ion and radiation transport calculations are in progress for conceptual beam dump designs for the fragmentation line of the proposed Rare Isotope Accelerator (RIA). Using the computer code PHITS, a preliminary design of a motor-driven rotating wheel beam dump and adjacent downstream multipole has been modeled. Selected results of these calculations are given, including neutron and proton flux in the wheel, absorbed dose and displacements per atom in the hub materials, and heating from prompt radiation and from decay heat in the multipole.

WPAE054 Irradiation Effects on RIA Fragmentation Cu Beam Dump 3265
  • S. Reyes, L. Ahle, J.L. Boles, W. Stein
    LLNL, Livermore, California
  • B.D. Wirth
    UCB, Berkeley, California
  Funding: U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

Within the scope of conceptual R&D activities in support of the Rare-Isotope Accelerator (RIA) facility, high priority is given to the development of high-power fragmentation beam dumps. A pre-study was made of a static water-cooled Cu beam dump that can meet requirements for a 400 MeV/u uranium beam. The issue of beam sputtering was addressed and found to be not a significant issue. Preliminary radiation transport simulations show significant damage (dpa) in the vicinity of the Bragg peak of uranium ions. Experimental data show that defects in Cu following neutron or high-energy particle irradiation tend to saturate at doses between 1 and 5 dpa, and this saturation in defect density also results in saturation of mechanical property degradation. However, effects of swift heavy ion irradiation and the production of gaseous and solid transmutant elements still need to be addressed. Initial calculations indicate that He concentrations on the order of 100 appm are produced in the beam dump after several weeks of continuous operation and He embrittlement should be a concern. Recommendations are made for further investigation of Cu irradiation effects RIA-relevant conditions.

WPAE056 Geant4-Based Simulation Study of PEP-II Beam Backgrounds in the BaBar Detector at the SLAC B-Factory 3351
  • W.S. Lockman
    SCIPP, Santa Cruz, California
  • D. Aston, G.R. Bower, M. Cristinziani, H. Fieguth, D. H. Wright
    SLAC, Menlo Park, California
  • N.R. Barlow, C.L. Edgar
    Manchester University, Manchester
  • N.L. Blount, D. Strom
    University of Oregon, Eugene, Oregon
  • M. Bondioli
    INFN-Pisa, Pisa
  • G. Calderini
    UNIPI, Pisa
  • B. Campbell, S.H. Robertson
    CHEP, Montreal, Quebec
  • W. Kozanecki
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • B.A. Petersen
    Stanford University, Stanford, Califormia
  To improve the understanding of accelerator-induced backgrounds at the SLAC B-Factory and validate the proposed PEP-II luminosity upgrade, we simulate lost-particle backgrounds in the BaBar detector originating from beam-gas interactions and radiative-Bhabha scatters. To perform this study, we have extended the GEANT4-based BaBar detector simulation to include PEP-II beam-line components and magnetic fields up to 10m away from the interaction point. We first describe the simulation model and then compare predicted background levels with measurements from dedicated single-and colliding-beam experiments. Finally, we compare the simulated background levels in the current and the proposed luminosity-upgrade configurations.  
WPAE057 Net Shape Manufacturing of Accelerator Components by High Pressure Combustion Driven Powder Compaction
  • K. Nagarathnam
    UTRON Inc, Manassas, Virginia
  Funding: Funding Agency: Department of Energy (DOE) Under SBIR Contracts#DE-FG02-02ER83567 and DE-FG02-03ER83816.

We present an overview of the net shape and cost-effective manufacturing aspects of high density accelerator (normal and superconducting) components (e.g., NLC Copper disks) and materials behavior of copper, stainless steel, refractory materials (W, Mo and TZM), niobium and SiC by innovative high pressure Combustion Driven Compaction (CDC) technology. Some of the unique process advantages include high densities, net-shaping, improved surface finish/quality, suitability for simple/complex geometries, synthesis of single as well as multilayered materials, milliseconds of compaction process time, little or no post-machining, and process flexibility. Some of the key results of CDC fabricated sample geometries, process optimization, sintering responses and structure/property characteristics such as physical properties, surface roughness/quality, electrical conductivity, select microstructures and mechanical properties will be presented. Anticipated applications of CDC compaction include advanced x-ray targets, vacuum seals, accelerator/RF microwave components, high temperature nozzle liner parts/heat sinks, and advanced high density magnets.

WPAE082 Design of a Precision Positioning System for the Undulators of the Linac Coherent Light Source 4099
  • E. Trakhtenberg, J.T. Collins, P.K. Den Hartog, M. White
    ANL, Argonne, Illinois
  A precision positioning system has been designed for the Linac Coherent Light Source (LCLS) and a prototype system is being fabricated. The LCLS will use a beam based alignment technique to precisely align all of the segments of the 130-m long undulator line. The requirement for overlap between the electron beam and the x-ray beam, in order to develop and maintain lasing, demands that each of the quadrupoles be aligned within a tolerance of ± 2 μm and that the undulator axis be positioned within ± 10 μm vertically and horizontally. Five cam movers, each with an eccentricity of 1.5 mm, will allow adjustment of a cradle supporting the undulator, its vacuum chamber, a quadrupole, and a beam position monitor. An additional motion transverse to the beam axis allows removal of individual undulators from the beam path. Positioning feedback will be provided by a wire position monitor system and a hydrostatic leveling system.  
WPAT095 Low-Loss Ferroelectric for Accelerator Application 4305
  • A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • A. Dedyk, S.F. Karmanenko
    Eltech University, St. Petersburg
  • E. Nenasheva
    Ceramics Ltd., St. Petersburg
  • V.P. Yakovlev
    Omega-P, Inc., New Haven, Connecticut
  Funding: U.S. Department of Energy.

Ferroelectric ceramics have an electric field-dependent dielectric permittivity that can be altered by applying a bias voltage. Ferroelectrics have unique intrinsic properties that makes them attractive for high-energy accelerator applications: very small response time of ~ 10-11 sec, considerably high breakdown limit of more than 100 kV/cm, good vacuum properties. Because of these features, bulk ferroelectrics may be used as active elements of tunable accelerator structures,* or in fast, electrically - controlled switches and phase shifters in pulse compressors or power distribution circuits of future linear colliders.** One of the most critical requirements for ferroelectric ceramic in these applications is the dielectric loss factor. In this paper, the new bulk ferroelectric ceramic is presented. The new composition shows a loss tangent of 4× 10-3 at 35 GHz. The ceramics have high tunability factor: the bias voltage of 50 kV/cm was enough to reduce the permittivity from 500 to 400. The material chemical compound, features of the technology process, and mechanical and electrical properties are discussed. The ways of BST ferrolectric parameters further improvement are discussed as well.

*A. Kanareykin, W. Gai, J. Power, E. Sheinman, and A. Altmark, AIP Conf. Proc. 647, Melville, N.Y., 2002, p. 565. **V.P. Yakovlev, O.A. Nezhevenko, J.L. Hirshfield, and A.D. Kanareykin, AIP Conf. Proc. 691, Melville, N.Y., 2003, p.187.