Low- and Medium-Energy Accelerators and Rings


Paper Title Page
FPAE027 Status of the ISAC-II Accelerator at TRIUMF 2003
  • R.E. Laxdal, W. Andersson, P. Bricault, I. Bylinskii, K. Fong, M. Marchetto, A.K. Mitra, R.L. Poirier, W.R. Rawnsley, P. Schmor, I. Sekachev, G. Stanford, G.M. Stinson, V. Zviagintsev
    TRIUMF, Vancouver
  A heavy ion superconducting linac is being installed at TRIUMF to increase the final energy of radioactive beams at ISAC. A first stage of 20MV consisting of five medium beta cryomodules each with four quarter wave bulk niobium cavities and a superconducting solenoid is being installed with initial beam commissioning scheduled for Dec. 2005. The initial cryomodule has met cryogenic and rf performance specifications. In addition we have demonstrated acceleration of alpha particles in an off-line test. A 500W refrigerator system has been installed and commissioned in Jan. 2005 with cold distribution due for commissioning in Sept. 2005. A transfer beamline from the ISAC accelerator and beam transport to a first experimental station are being installed. The status of the project will be presented.  
FPAE028 Design of the High Intensity Exotic Beams SPIRAL 2 Project 2044
  • A. Mosnier
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • M.H. Moscatello
    GANIL, Caen
  The SPIRAL 2 facility will be able to deliver stable heavy ion beams and deuteron beams at very high intensity, allowing to produce and accelerate light and heavy rare ion beams. The driver will accelerate a 5 mA deuteron beam up to 20 MeV/u and also q/A=1/3 heavy ions up to 14.5 MeV/u. The injector consist of the ion sources, a 4-vane RFQ and the low and medium beam transfer lines. It is followed by an independently phased superconducting linac with compact cryostats separated with warm focusing sections. The overall design and results of simulations with combined errors, the results of tests of prototypes for the most critical components are presented.  
FPAE029 Setup and Performance of the RHIC Injector Accelerators for the 2005 Run with Copper Ions 2068
  • C.J. Gardner, L. Ahrens, J.G. Alessi, J. Benjamin, M. Blaskiewicz, J.M. Brennan, K.A. Brown, C. Carlson, J. DeLong, J. Glenn, T. Hayes, W.W. MacKay, G.J. Marr, J. Morris, T. Roser, F. Severino, K. Smith, D. Steski, N. Tsoupas, A. Zaltsman, K. Zeno
    BNL, Upton, Long Island, New York
  Funding: Work performed under the auspices of the U.S. Department of Energy.

Copper ions for the 2005 run of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory are accelerated in the Tandem, Booster and AGS prior to injection into RHIC. The setup and performance of this chain of accelerators will be reviewed.

FPAE031 Polarized Electron Beams for Nuclear Physics at the MIT Bates Accelerator Center
  • M. Farkhondeh, dc. Cheever, W.A. Franklin, E. Ihloff, B. McAllister, R. Milner, W. North, C. Tschalaer, E. Tsentalovich, D. Wang, D. Wang, F. Wang, A. Zolfaghari, T. Zwart, J. van der Laan
    MIT, Middleton, Massachusetts
  Funding: U.S. Department of Energy.

The MIT Bates Accelerator Center is delivering highly polarized electron beams to its South Hall Ring for use in Nuclear Physics Experiments. Circulating electron currents in excess of 200 mA with polarization of 70% are scattered from a highly polarized, but very thin atomic beam source deuterium target. At the electron source a compact diode laser creates photoemission of quasi-CW mA pulses of polarized electrons at low duty factors from a strained GaAs photocathode. Refurbished RF transmitters provide power to the 2856 MHz linac, accelerating the beam to 850 MeV in two passes before injection into the South Hall Ring. In the ring a Siberian snake serves to maintain a high degree of longitudinal polarization at the BLAST scattering target. A Compton laser back-scattering polarimeter measures the electron beam polarization with a statistical acuracy of 6% every 15 minutes.

FPAE032 ORIC Beam Energy Increase 2257
  • M.L. Mallory, J.B. Ball, D. Dowling, E. D. H. Hudson, R. S. L. Lord, A. Tatum
    ORNL, Oak Ridge, Tennessee
  Funding: Managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05=00OR 22725.

The detection of and solution to a beam interference problem in the Oak Ridge Isochronous Cyclotron (ORIC) extraction system has yielded a 20% increase in the proton beam energy. The beam from ORIC was designed to be extracted before the nu r equal one resonance. Most cyclotrons extract after the nu r equal one resonance, thus getting more usage of the magnetic field for energy acceleration. We have now determined that the electrostatic deflector septum interferes with the last accelerated orbit in ORIC, with the highest extraction efficiency obtained near the maximum nu r value. This nu r provides a rotation in the betatron oscillation amplitude that is about the same length as the electrostatic septum thus allowing the beam to jump over the interference problem with the septum. With a thinned septum we were able to tune the beam through the nu r equal one resonance and achieve a 20% increase in beam energy. This nu r greater than one extraction method may be desirable for very high field cyclotrons since it provides ten times the clearance at extraction compared to dee voltage gain, thus allowing the possibility of utilizing a magnetic extractor.

FPAE033 Operational Availability of the SNS During Commissioning 2289
  • G.W. Dodson, 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. Operating statistics were taken and used by system owners to target developments to improve accelerator availability. This progression will be shown along with the overall availability goals of the SNS and a RAM calculation showing the system and subsystem availability required to meet these goals.

FPAE035 Steps Towards a 3 mA, 1.8 MW Proton Beam at the PSI Cyclotron Facility 2405
  • P.A. Schmelzbach, S.R.A. Adam, A. Adelmann, H. Fitze, G. Heidenreich, J.-Y. Raguin, U. Rohrer, P.K. Sigg
    PSI, Villigen
  The PSI Cyclotron Facility produces routinely a 1.8-1.9 mA proton beam at 590 MeV. The beam power reaches 1.1 MW at the the pion production targets and 0.7 MW at the neutron spallation target SINQ. The accelerator complex will be analysed in respect to his potential for future improvements. The ongoing developments aiming to increase the beam intensity to 3 mA and hence the beam power to 1.8 MW will be discussed. Smooth extrapolations of the observed machine parameters as well as recent advances in the theoretical treatment of space charge dominated beams show that this goal can be achieved with available technologies. IA new RF-cavity operated at a voltage in excess of 1 MV has been successfully tested and installed in the Ring Cyclotron. Bunchers for the low energy and the medium energy transfer lines are in the design phase. A conceptual study of new accelerating cavities to replace the obsolete flattop-cavities of the Injector Cyclotron has been performed. While the upgrade of the Ring Cyclotron with four new cavities will be completed in 2008, it is still an open question whether this accelerator will be operated in the "round beam" mode like the Injector Cyclotron or with an upgraded flattopping system.  
FPAE036 Lattice Modification of a 1.2 GeV STB Ring for Generation of High Energy Gamma-Rays Using Internal Target Wire 2458
  • F. Hinode, H. Hama, M. Kawai, A. Kurihara, A. Miyamoto, M. Mutoh, M. Nanao, Y. Shibasaki, K. Shinto, S. Takahashi, T. Tanaka
    LNS, Sendai
  A 1.2 GeV Stretcher-Booster Ring (STB ring) has been routinely operated at Laboratory of Nuclear Science (LNS), Tohoku University. The STB ring has functions of a pulse-beam stretcher and a booster-storage ring. In the booster-storage operation, high energy gamma-ray beam generated via bremsstrahlung from internal target wire is utilized for experiments of nuclear physics. Some fractions of circulating electrons are also deflected in the target wire due to Coulomb scattering without significant loss of the energy. The scattered electrons that are not getting out of the dynamic aperture once can circulate in the ring. Such electrons, however, would hit the chamber walls and supports of the target wire during further turns, because they have very large betatron amplitude. Consequently the Coulomb scattered electrons must be a source of significant background and may cause a degradation of gamma-ray beam quality. The quality of the gamma-ray beam has been improved by modifying the lattice functions of the ring, and we report the improvement in this conference.