ROPC  —  Low- and Medium-Energy Accelerators and Rings   (19-May-05   13:50—17:20)

Chair: M.A. Plum, ORNL, Oak Ridge, Tennessee

Paper Title Page
ROPC001 SNS Warm Linac Commissioning Results 97
  • A.V. Aleksandrov
    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 accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of an H- injector, capable of producing one-ms-long pulses at 60Hz repetition rate with 38 mA peak current, a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The 2.5MeV beam from the Front End is accelerated to 86 MeV in the Drift Tube Linac, then to 185 MeV in a Coupled-Cavity Linac and finally to 1 GeV in the Superconducting Linac. The staged beam commissioning of the accelerator complex is proceeding as component installation progresses. The Front End, Drift Tube Linac and three of the four Coupled-Cavity Linac modules have been commissioned with beam at ORNL. Results and status of the beam commissioning program will be presented.

ROPC002 J-PARC Commissioning Results 220
  • K. Hasegawa
    JAERI, Ibaraki-ken
  The J-PARC (Japan Proton Accelerator Research Complex)comprises a 400-MeV linac, a 3-GeV rapid-cycling synchrotron (RCS), a 50-GeV main ring synchrotron (MR) and experimental facilities. A peak current of 30 mA was accelerated up to 20 MeV of the DTL beam commissioning at the KEK site. The buildings and conventional facilities will be completed in succession in the Japanese Fiscal Year 2005, when the installation of the accelerator components will be actually started at Tokai site. The beam commissioning of the 181 MeV linac will be started in September, 2006, followed by the RCS and MR beam commissioning. To achieve the high beam power with low beam loss, the J-PARC accelerators are based on many newly developed technologies; pi-mode stabilizing loops in the RFQ, RF choppers in the medium energy beam transport, magnetic alloy loaded RF cavities in the synchrotrons, etc. The recent results of the developments of these new technologies, the present construction status and the commissioning schedule will be presented.  
ROPC003 RIKEN RI Beam Factory Project 320
  • Y. Yano
    RIKEN/RARF/CC, Saitama
  The world-top-class radioactive-isotope-beam (RIB) facility, which is called ?RI beam factory (RIBF)?, is under construction at RIKEN. This facility is based on the so-called ?in-flight RI beam separation? scheme. Late in 2006, a new high-power heavy-ion accelerator system consisting of a cascade of three ring cyclotrons with K=570 MeV (fixed frequency, fRC), 980 MeV (Intermediate stage, IRC) and 2500 MeV (superconducting, SRC), respectively, will be commissioned. This new accelerator system will boost energies of the output beams from the existing K540-MeV ring cyclotron up to 440 MeV/nucleon for light ions and 350 MeV/nucleon for very heavy ions. These energetic heavy-ion beams are converted into intense RI beams via the projectile fragmentation or in-flight fission of uranium ions by the superconducting isotope separator, BigRIPS, under construction. The combination of the SRC and BigRIPS will expand our nuclear world into presently unreachable region. Major experimental installations are under priority discussion as the second phase program. Construction of the second phase is expected to start in 2006.  
ROPC004 Recent Intensity Increase in the CERN Accelerator Chain 413
  • E.N. Shaposhnikova, G. Arduini, T. Bohl, M. Chanel, R. Garoby, S. Hancock, K. Hanke, T.P.R. Linnecar, E. Métral, R.R. Steerenberg, B. Vandorpe
    CERN, Geneva
  Future requests for protons from the physics community at CERN, especially after the start-up of the CNGS experiments in 2006, can only be satisfied by a substantial increase in the SPS beam intensity per pulse. In September 2004 a three weeks beam run was dedicated to high intensity; all accelerators in the chain were pushed to their limits to study intensity restrictions and find possible solutions. New record intensities were obtained in the accelerators of the PS & SPS Complex with this fixed-target type beam which is different from the nominal LHC beam. The challenges in producing this high-intensity beam are described together with the measures needed to make it fully operational.  
ROPC005 RIA Post Accelerator Design 425
  • S.O. Schriber
    NSCL, East Lansing, Michigan
  Overall design of the post accelerator for the RIA project is described with emphasis on performance for different ion beams. Characteristics for beams from A=10 to A=240 will be provided with an estimate of output intensities. The rational for selection of different accelerating structures, both for the normal conducting and for the superconducting types, will be provided for a system design that accelerates beams to at least 10 MeV/u.  
ROPC006 Commissioning of Fermilab's Electron Cooling System for 8-GeV Antiprotons 540
  • S. Nagaitsev, D.R. Broemmelsiek, A.V. Burov, K. Carlson, C. Gattuso, M. Hu, B.J. Kramper, T.K. Kroc, J.R. Leibfritz, L.R. Prost, S.M. Pruss, G.W. Saewert, C.W. Schmidt, A.V. Shemyakin, M. Sutherland, V. Tupikov, A. Warner
    Fermilab, Batavia, Illinois
  • W. Gai
    ANL, Argonne, Illinois
  • G.M. Kazakevich
    BINP SB RAS, Novosibirsk
  • S. Seletsky
    Rochester University, Rochester, New York
  A 4.3-MeV electron cooling system has been installed at Fermilab in the Recycler antiproton storage ring and is being currently commissioned. The cooling system is designed to assist accumulation of 8.9-GeV/c antiprotons for the Tevatron collider operations. This paper will report on the progress of the electron beam commissioning effort as well as on detailed plans of demonstrating the cooling of antiprotons.  
ROPC007 Status of the Proton Engineering Frontier Project 576
  • B.H. Choi
    KAERI, Daejon
  Funding: This work is supported by the 21C Frontier R&D program in the Ministry of Science and Technology of the Korean government.

The Proton Engineering Frontier Project (PEFP) approved and launched by the Korean government in July 2002 includes a 100MeV proton linear accelerator development and a program for its utilization. The first phase of the project, running from 2002 to 2005, was the design of a 100MeV proton linear accelerator and a part of development to 20 MeV. This consists of a 50 keV proton injector, a 3 MeV radio frequency quadrupole (RFQ), and a 20MeV drift tube linac (DTL). The 50 keV injector and the 3 MeV RFQ has been installed and tested, and the 20 MeV DTL is being assembled and tuned for beam tests. At the same time, the utilization programs using the proton beam have been planned, and some are now under way. The status and progress of the project are reported in detail.

ROPC008 Experimental Progress in Fast Cooling in the ESR 615
  • M. Steck, K. Beckert, P. Beller, B.  Franzke, F. Nolden
    GSI, Darmstadt
  The ESR storage ring at GSI is operated with highly charged heavy ions. Due to the high electric charge the ions interact much stronger with electromagnetic fields. Therefore both cooling methods which are applied to stored ions in the ESR, stochastic cooling and electron cooling, are more powerful than for singly charged particles. The experimental results exhibit cooling times for stochastic cooling of a few seconds. For cold ion beams, electron cooling provides cooling times which are one to two orders of magnitude smaller. The beams are cooled to beam parameters which are limited by intrabeam scattering. At small ion numbers, however, intrabeam scattering is suppressed by electron cooling, clear evidence was found that the ion beam forms a one-dimensional ordered structure, a linear chain of ions. The strengths of stochastic cooling and electron cooling are complementary and can be combined favorably. Stochastic cooling is employed for pre-cooling of hot secondary beams followed by electron cooling to provide ultimate beam quality. In a similar manner, first experiments with carbon ions have been performed to use electron cooling as a pre-cooling method in combination with laser cooling.  
ROPC009 First Acceleration with Superconducting RF Cavities at ISAC-II 662
  • R.E. Laxdal, K. Fong, M. Marchetto, W.R. Rawnsley, V. Verzilov
    TRIUMF, Vancouver
  We have demonstrated the first acceleration of ions with superconducting rf at TRIUMF/ISAC. Alpha particles from a radioactive source were accelerated from 2.8MeV through the ISAC-II medium beta cryomodule to a maximum energy of 9.4 MeV. The four 106 MHz quarter wave cavities (beta_o=7%) were set to the ISAC-II specified gradient of 6 MV/m (Leff=18cm, Ep=30MV/m and Veff=1.08MV) with a cavity power of about 6W per cavity. The final particle energy spectra was measured with a silicon detector. The initial alpha energy corresponds to a velocity of beta=3.9% giving an expected T/To efficiency of 0.48, 0.76, 0.92 and 0.99 for the four cavities respectively and an expected final energy of 9.6MeV. The experimental set-up including details of the source and diagnostic boxes and the detector electronics are described. Beam simulations of the unbunched, uncollimated beam indicate a unique spectral fingerprint that can be used to unambiguously determine each cavity voltage.  
ROPC010 Testing, Installation, Commissioning and First Operation of the ISIS RFQ Pre-Injector Upgrade 695
  • A.P. Letchford, D.C. Faircloth, D.J.S. Findlay, M. Perkins, A.F. Stevens, M. Whitehead
    CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
  Situated at the Rutherford Appleton Laboratory (Oxon., UK), ISIS is currently the world's most intense pulse spallation neutron source, delivering 160 kW of 800 MeV protons to a tungsten target at 50 Hz. A major facility upgrade programme involves the construction of a second, 10 Hz target and an increase in the total beam power of up to 50% (i.e. up to 240 kW). To achieve the planned increase in average beam current to 300 μA whilst maintaining the current manageable levels of beam loss, four 2nd harmonic RF cavities have been installed in the synchrotron and the ageing Cockroft-Walton pre-injector in the linac has been replaced with a 665 keV, 202.5 MHz, 4-rod RFQ. This paper describes the extensive testing, installation, commissioning and successful initial operation of the RFQ pre-injector upgrade.