Low- and Medium-Energy Accelerators and Rings

Circular Accelerators

Paper Title Page
FPAE001 Design Work for the High-Energy Storage Ring for Antiprotons of the Future GSI Project 776
  • A. Lehrach, S. An, K. Bongardt, J. Dietrich, R. Eichhorn, B. Lorentz, R. Maier, S. Martin, D. Prasuhn, Y. Senichev, E.A. Senicheva, H. Stockhorst, R. Tölle, E. Zaplatin
    FZJ, Jülich
  • O. Boine-Frankenheim, A. Dolinskii, M. Steck
    GSI, Darmstadt
  • B. Gålnander, D. Reistad
    TSL, Uppsala
  • F.H. Hinterberger
    Universität Bonn, Helmholtz-Institut für Strahlen- und Kernphysik,, Bonn
  The High-Energy Storage Ring (HESR) of the future international Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is planned as an antiproton cooler and storage ring in the momentum range from 1.5 to 15 GeV/c. The design work for the HESR is organized by a consortium with scientists from FZ Jülich, GSI Darmstadt and TSL Uppsala. An important feature of the new facility is the combination of phase space cooled beams with internal targets, resulting in demanding beam parameter in two operation modes: high luminosity mode with beam intensities up to few times 1011, and high resolution mode with a momentum spread down to 10-5, respectively. To reach these beam parameters very powerful phase space cooling is needed, utilizing high-energy electron cooling and high-bandwidth stochastic cooling. In this paper an overview of the design work is given, focusing on recent developments and planned R&D work.  
FPAE004 Optical Matching of Slowly Extracted Beam with Transport System at HIMAC 910
  • T. Furukawa, K. Noda, E. Takada, M. Torikoshi, T.H. Uesugi, S. Yamada
    NIRS, Chiba-shi
  • T. Fujimoto, M. Katsumata, S. Shibuya, T. Shiraishi
    AEC, Chiba
  The optical matching between the ring and the transport line plays important role in order to control the beam size and profile after the transport. At HIMAC, thus, we have studied the optical matching of the slowly extracted beam. As a result, it was verified that the beam size of the slowly extracted beam were controlled owing to the optical matching. It was also found that small deviation of quadrupole strength in the ring brings orbit distortion at the transport system.  
FPAE005 Characteristics of Injected Beam at HIMAC Synchrotron 952
  • T.H. Uesugi, T. Furukawa, K. Noda, S. Shibuya
    NIRS, Chiba-shi
  At the HIMAC synchrotron, we have carried out the tune survey with the lifetime measurement in order to obtain the high intensity. Under the relatively high intensity, it was observed that a part of the circulating beam was lost due to the coherent oscillation in both the horizontal and the vertical direction. Taking account of the tune shift and spreads, the working point was optimized so as to avoid resonance line. We will describe the experimental result.  
FPAE006 Optimization of AGS Polarized Proton Operation with the Warm Helical Snake 1003
  • J. Takano, M. Okamura
    RIKEN, Saitama
  • L. Ahrens, M. Bai, K.A. Brown, C.J. Gardner, J. Glenn, H. Huang, A.U. Luccio, W.W. MacKay, T. Roser, S. Tepikian, N. Tsoupas
    BNL, Upton, Long Island, New York
  • T. Hattori
    RLNR, Tokyo
  Funding: US DOE and RIKEN Japan.

A normal conducting helical dipole partial Siberian snake (Warm Snake) has been installed in the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL) for overcoming all of imperfection depolarizing resonances and reducing the transverse coupling resonances caused by the solenoidal Siberian snake which had been operated in AGS before the last polarized run. The polarized proton beam has been accelerated successfully with the warm snake and the polarization at extraction of the AGS was increased to 50% as opposed to 40% with the solenoidal snake. The magnetic field and beam trajectory in the warm snake was calculated by using the OPERA-3D/TOSCA software. We present optimization of the warm snake with beam during RUN5.

FPAE007 A Project of the 2.5 GeV Booster-Synchrotron in BINP 1039
  • V.A. Kvardakov, V. Barbashin, V. Kiselev, E.V. Kremyanskaya, E. Levichev, S.I. Mishnev, V. Petrov, A.N. Skrinsky, V.V. Smaluk, I. Zemlyansky
    BINP SB RAS, Novosibirsk
  A project of the 2.5 GeV booster synchrotron to provide effective injection of electron and positron beams into VEPP-2000 and VEPP-4M storage rings, and for future facilities, is developing in BINP. The beams are injected to synchrotron at 510 MeV energy from a damping ring, which is the part of the new injection facility. In this report, the synchrotron parameters are presented, the basic systems are briefly described.  
FPAE008 Iso-Adiabatic Merging of pbar Stacks in the Recycler 1093
  • C.M. Bhat
    Fermilab, Batavia, Illinois
  Funding: Work supported by the Universities Research Association, Inc., under contract DE-AC02-76CH03000 with the U.S. Department of Energy.

Here, I have proposed an efficient scheme to merge two stacks of pbars in the Recycler* with emittance dilution <15%. First I discuss a method to match energy spreads of the two stacks and subsequently merging them. The scheme is illustrated with multiparticle dynamics simulations and beam measurements in the Recycler.

*G. Jackson, Fermilab-TM-1991, November, 1996.

FPAE009 Bunched Beam Cooling in the Fermilab Recycler 1153
  • D.V. Neuffer, D.R. Broemmelsiek, A.V. Burov, S. Nagaitsev
    Fermilab, Batavia, Illinois
  Stochastic cooling with bunched beam in a linear bucket has been obtained and implemented operationally in the fermilab recycler. In this implementation the particle bunch length is much greater than the cooling system wavelengths. The simultaneous longitudinal bunching enables cooling to much smaller longitudinal emittances than the coasting beam or barrier bucket system. Characteristics and limitations of bunched beam stochastic cooling are discussed.  
FPAE010 Barrier RF System and Applications in Main Injector 1189
  • W. Chou, D. Wildman
    Fermilab, Batavia, Illinois
  • A. Takagi
    KEK, Ibaraki
  • H. Zheng
    CALTECH, Pasadena, California
  Funding: Work supported by the Universities Research Association, INC. under contract with the U.S. Department of Energy NO. DE-AC02-76CH03000 and by the US-Japan Collaboration in High Energy Physics.

A wideband RF system (the barrier RF) has been built and installed in the Fermilab Main Injector. The cavities are made of low Q Finemet cores. The modulators use high voltage fast solid-state switches. It can generate ±7 kV single square voltage pulses. It is used to stack two proton batches to double the bunch intensity for pbar production. The stacked high intensity beams have been successfully accelerated to 120 GeV with small losses. A new test to continuously stack 12 batches for the NuMI experiment is under way.

FPAE012 Experimental Test of a New Antiproton Acceleration Scheme in the Fermilab Main Injector 1303
  • V. Wu, C.M. Bhat, B. Chase, J.E. Dey, K.G. Meisner
    Fermilab, Batavia, Illinois
  Funding: Operated by Universities Research Association, Inc. for the U.S. Department of Energy under contract DE-AC02-76CH03000.

In an effort to provide higher intensity and lower emittance antiproton beam to the Tevatron collider for high luminosity operation, a new Main Injector (MI) antiproton acceleration scheme has been developed [1-4].* In this scheme, beam is accelerated from 8 to 27 GeV using the 2.5 MHz rf system and from 27 to 150 GeV using the 53 MHz rf system. This paper reports the experimental results of beam study. Simulation results are reported in a different PAC'05 paper [5]. Experiments are conducted with proton beam from the Booster. Acceleration efficiency, emittance growth and beam harmonic transfer between 2.5 MHz (h=28) and 53 MHz (h=588) buckets have been studied. Beam study shows that one can achieve an overall acceleration efficiency of about 100%, longitudinal emittance growth less than 20% and negligible transverse emittance growth.

*G. P. Jackson, The Fermilab Recycler Ring Technical Design Report, FERMILAB-TM-1991, November 1996.

FPAE013 Calculation of the Orbit Length Change of the Recycler Due to Main Injector Ramp 1318
  • M. Xiao
    Fermilab, Batavia, Illinois
  Orbit length of beam in the Recycler changes during the Main Injector ramps. The unknown kicks from the effects generated by stray field are distributed around the ring. To estimate the changes, simulated virtual kicks are created around each lambson, C-magnet and bus cable of the Main Injector. The orbit lengths are calculated from measurements of evolution frequency and transverse beam positions. A BPM system distributed throughout the Recycler lattice in both Horizontal and vertical planes are used to take the closed orbit measurement during the ramps. The calculation method and the results of the orbit length changes and the strength of the simulated kicks are presented in this report.  
FPAE014 Acceleration of Polarized Protons in the AGS with Two Helical Partial Snakes 1404
  • H. Huang, L. Ahrens, M. Bai, A. Bravar, K.A. Brown, G. Bunce, E.D. Courant, C.J. Gardner, J. Glenn, R.C. Gupta, A.U. Luccio, W.W. MacKay, V. Ptitsyn, T. Roser, S. Tepikian, N. Tsoupas, E. Willen, A. Zelenski, K. Zeno
    BNL, Upton, Long Island, New York
  • F. Lin
    IUCF, Bloomington, Indiana
  • M. Okamura
    RIKEN/RARF/CC, Saitama
  • J. Takano
    RIKEN, Saitama
  • D.G. Underwood
    ANL, Argonne, Illinois
  • J. Wood
    UCLA, Los Angeles, California
  Funding: Work supported by U.S. DOE and RIKEN of Japan.

The RHIC spin program requires 2*1011 proton/bunch with 70% polarization. As the injector to RHIC, AGS is the bottleneck for preserving polarization: there is not enough space in the ring to install a full snake to overcome the numerous depolarizing resonances. An ac dipole and a partial Siberian snake have been used to preserve beam polarization in the past. The correction with this scheme is not 100% since not all depolarizing resonances can be overcome. Recently, two helical snakes with double pitch design have been built and installed in the AGS. With careful setup of optics at injection and along the ramp, this combination can eliminate all depolarizing resonances encountered during acceleration. This paper presents the accelerator setup and preliminary results.

FPAE016 Spallation Neutron Source Ring - Design and Construction Summary 1499
  • 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.

(J. Wei for the Spallation Neutron Source Collaboration) After six years, the construction of the Spallation Neutron Source (SNS) accumulator ring [1] and the transport lines is completed in March 2005. Designed to deliver 1.5 MW beam power (1.5 x 1014 protons of 1 GeV kinetic energy at a repetition rate of 60 Hz), stringent measures have been implemented in the fabrication, test, and assembly to ensure the quality of the accelerator systems. This paper summarizes the construction of the ring and transport systems with emphasis on the challenging technical issues and their solutions [2].

[1] J. Wei, et al, Phys. Rev. ST-AB, Vol. 3, 080101 (2000). [2] J. Wei, "Synchrotrons and Accumulators for High-Intensity Proton Beams", Rev. Mod. Phys., Vol. 75, 1383 – 1432 (2003).

FPAE017 Observation of Longitudinal Diffusion and Cooling Due to Intrabeam Scattering at the Fermilab Recycler Ring 1560
  • M. Hu, S. Nagaitsev
    Fermilab, Batavia, Illinois
  The Fermilab Recycler Ring is a high vacuum fixed energy antiproton storage ring with both stochastic and electron cooling systems. In this note the technique for diffusion rate measurement, beam parameters and the analysis of data are presented, as well as the effect of intrabeam scattering on the operational considerations for the storage and cooling of the antiproton beam in the Recycler.  
FPAE019 Booster 6-GeV Study 1637
  • X. Yang, C.M. Ankenbrandt, J.R. Lackey, R.D. Padilla, W. Pellico
    Fermilab, Batavia, Illinois
  • J. Norem
    ANL, Argonne, Illinois
  Funding: Fermi National Accelerator Laboratory, Accelerator Division, Proton Source Department.

Since a wider aperture has been obtained along the Fermilab Booster beam line, this opens the opportunity for Booster running a higher intensity proton beam than ever before. Sooner or later, the available RF accelerating voltage will become a new limit for the beam intensity. Either by increasing the RF accelerating voltage or by reducing the accelerating rate can achieve the similar goal. The motivation for the 6-GeV study is to gain the relative accelerating voltage via a slower acceleration.

FPAE020 Induction Acceleration of a Single RF Bunch in the KEK PS 1679
  • K. Takayama, D.A. Arakawa, Y.A. Arakida, S. Igarashi, T. Iwashita, T. Kono, E. Nakamura, M. Sakuda, H. Sato, Y. Shimosaki, M.J. Shirakata, T. Sueno, K. Torikai, T. Toyama, M. Wake, I. Yamane
    KEK, Ibaraki
  • K. Horioka
    TIT, Yokohama
  • A.K. Kawasaki, A. Tokuchi
    NICHICON, Shiga
  • J. Kishiro
    JAERI/LINAC, Ibaraki-ken
  • K. Koseki
    GUAS/AS, Ibaraki
  • M.S. Shiho
    JAERI/NAKA, Ibaraki-ken
  • M. Watanabe
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  A single bunch trapped in an RF bucket was accelerated by induction devices from 500 MeV to 8GeV beyond transition energy in the KEK-PS. This is the first demonstration of induction acceleration in a high energy circular ring. The acceleration was confirmed by measuring a temporal evolution of the RF phase through an entire acceleration.* Key devices in an induction acceleration system are an induction accelerating cavity capable of generating an induced voltage of 2kV/cell, a pulse modulator to drive the cavity (switching driver), and a DSP system to control gate signals for switching. Their remarkable characteristics are its repetition ratio of about 1MHz and duty factor of 50%. All devices have been newly developed at KEK so as to meet this requirement. The pulse modulator employing MOSFETs as switching elements is connected with the accelerating cavity through a long transmission cable in order to avoid a high-dose irradiation in the accelerator tunnel. The induction system has been running beyond more than 24 hours without any troubles. The paper will take an introductive role for related other 6 papers too, which describe more technical aspects and novel beam physics associated with the induction acceleration.

*K.Takayama et al., submitted to Phys. Rev. Lett., http://www.arxiv.org/pdf/physics/0412006.

FPAE021 Alignment and Steering for Injection and Multi-Turn Operation of the University of Maryland Electron Ring (UMER) 1709
  • M. Walter, G. Bai, S. Bernal, I. Haber, M. Holloway, R.A. Kishek, P.G. O'Shea, B. Quinn
    IREAP, College Park, Maryland
  • M. Reiser
    University Maryland, College Park, Maryland
  Funding: This work is funded by US Dept. of Energy grant numbers DE-FG02-94ER40855 and DE-FG02-92ER54178.

The injection line and main lattice for the University of Maryland Electron Ring (UMER) has been completed. The electron beam has been guided around the full 360 degrees of the ring. Beam steering and matching in the injection line is achieved with six quadrupole magnets and several small steering dipole magnets. The dipole component of an offset quadrupole and a pulsed dipole are used to achieve the 10 degree bend required from the injection line into the ring. The pulsed dipole is designed to operate with a short pulse (2 kV, -30 A, 100 ns flat top duration) for injection superimposed on a long pulse (300 V, 15 A, 20·10-6 s duration) for multiple beam passes. The beam is controlled in the recirculating ring with a regular lattice of 36 dipole and 72 quadrupole magnets. Initial experimental results of the beam transport and control will be presented.

FPAE022 Cycle-to-Cycle Extraction Synchronization of the Fermilab Booster for Multiple Batch Injection to the Main Injector 1802
  • R.M. Zwaska, S.E. Kopp
    The University of Texas at Austin, Austin, Texas
  • W. Pellico
    Fermilab, Batavia, Illinois
  We report on a system to ensure cycle-to-cycle synchronization of beam extraction from the Fermilab Booster accelerator to the Main Injector. Such synchronization is necessary for multiple batch operation of the Main Injector for the Run II upgrade of anti-proton production using slip-stacking in the Main Injector, and for the NuMI (Neutrinos at the Main Injector) neutrino beam. To perform this task, a system of fast measurement and feedback is used to control the longitudinal progress of the Booster beam throughout its acceleration period by manipulation of the transverse position maintained by the low-level radio frequency system.  
FPAE023 Direct Antiproton Deceleration in the Fermilab Proton Driver 1817
  • G.P. Jackson, S.D. Howe
    Hbar Technologies, LLC, West Chicago, Illinois
  The Fermilab Proton Driver is an 8 GeV kinetic energy H- linear accelerator proposed as a new source of high brightness protons for the Main Injector. The Recycler ring is an 8 GeV antiproton storage ring that resides in the same tunnel as the Main Injector. This paper describes a scenario wherein the current Main Injector proton injection kickers and Lambertson magnet are moved vertically into the Recycler ring to enable antiproton extraction toward the Proton Driver. By employing a pair of intermediate vertical bends at the appropriate vertical betatron phase advance, the vertical dispersion into the Proton Driver can be eliminated and direct antiproton deceleration made possible. Because the H- and antiproton beams have the same charge but opposite direction, matching of the Recycler lattice to the Proton Driver is required to accommodate the reversed effect of the focusing and defocusing quadrupoles.  
FPAE024 Studies Performed in Preparation for the Spallation Neutron Source Accumulator Ring Commissioning 1859
  • S.M. Cousineau, V.V. Danilov, S. Henderson, J.A. Holmes, M.A. Plum
    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 accumulator ring will compress 1.5?1014, 1 GeV protons from a 1 ms bunch train to a single 695 ns proton bunch for use in neutron spallation. Due to the high beam power, unprecedented control of beam loss will be required in order to control radiation and allow for hands-on maintenance in most areas of the ring. A number of detailed investigations have been performed to understand the primary sources of beam loss and to predict and mitigate problems associated with radiation hot spots in the ring. The ORBIT particle tracking code is used to perform realistic simulations of the beam accumulation in the ring, including detailed modeling of the injection system, transport through the measured magnet fields including higher order multipoles, and beam loss and collimation. In this paper we present the results of a number of studies performed in preparation for the 2006 commissioning of the accumulator ring.

FPAE025 Study of Slow Beam Extraction Through the Third Order Resonance with Transverse Phase Space Manipulation by a Mono-Frequency RFKO 1892
  • A. Miyamoto, H. Hama, F. Hinode, M. Kawai, K. Shinto, T. Tanaka
    LNS, Sendai
  An electron pulse-stretcher ring (STB ring) has a function which converts a pulse beam generated by RF linac into a quasi-continuous beam. Circulating beam in the ring is extracted by the third order resonance. Since there is no accelerating field in the ring, the beam approaches a transverse resonance condition due to synchrotron radiation loss with finite chromaticity. The extracted beam from the ring has some spread in time and space corresponding to injected beam from linac even if the injected beam is perfectly matched to the ring optics. However, the extracted beam emittance can be reduced by applying a phase space manipulation using an RF shaker. Under the influence of perturbation using an RF shaker driven by a mono-frequency, the betatron amplitude of circulating beam can be controlled in order to reduce the extracted beam emittance. The experimental results will be reported in this conference.  
FPAE026 Development of FFAG Accelerator at KEK 1943
  • Y. Yonemura, N. Ikeda, M. Matoba
    Kyushu University, Fukuoka
  • M. Aiba, S. Machida, Y. Mori, A. Muto, J. Nakano, C. Ohmori, K.O. Okabe, I. Sakai, Y. Sato, A. Takagi, T. Yokoi, M. Yoshii, Y. Yuasa
    KEK, Ibaraki
  • R. Taki
    GUAS/AS, Ibaraki
  • T. Uesugi
    NIRS, Chiba-shi
  • A. Yamazaki
    LNS, Sendai
  • M. Yoshimoto
    JAERI, Ibaraki-ken
  The 150MeV proton FFAG accelerator is constructed and a beam is extracted at the final energy. This is the prototype FFAG for various applications such as proton beam therapy. We are now in preparation for using an extracted beam in the practical applications.