Session 8: Low and Intermediate Energy Accelerators and Sources spc coordinator: K. Blasche, gsi, Darmstadt




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Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
18-931 - Construction Status and Issues of the Spallation Neutron Source Ring

Jie Wei (BNL, Upton, Long Island, New York)

(For the Spallation Neutron Source collaboration) The Spallation Neutron Source (SNS) accelerator complex is now in its sixth year of a seven-year construction cycle. The design, fabrication, test, and assembly of the accumulator ring and its transport lines is approaching the final stage. In order to reach the design goal of this high-power ring to deliver 1.5 MW beam power (1.5$\times 10^{14}$ protons of 1 GeV kinetic energy at a repetition rate of 60 Hz), stringent measures have been implemented to ensure the quality of the accelerator systems. This paper reviews the progress of the ring and transport systems with emphasis on the challenging technical issues and their solutions inccurred during the construction period.

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



Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
19-1056 - Acceleration of Polarized Beams using Multiple Strong Partial Siberian Snakes

Thomas Roser, Leif Ahrens, Mei Bai, Ernest D. Courant, Joseph Glenn, Ramesh C. Gupta, Haixin Huang, Alfredo U Luccio, Waldo MacKay, Nicholaos Tsoupas, Erich Willen (BNL, Upton, Long Island, New York), Masahiro Okamura (RIKEN/RARF/CC, Saitama)

Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20 - 30 % partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

This work was performed under the auspices of the US DOE and RIKEN of

Japan.


Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
20-1106 - Precise Field Mapping System for Cyclotron Magnet

Ki-Hyeon Park, Young Gyu Jung, Dong Eon Kim (PAL, Pohang), Jong-Seo Chai, Yoo-Seok Kim (KIRAMS, Seoul), Bong-Koo Kang (POSTECH, Pohang), Moohyun Yoon (POSTECH, Pohang, Kyungbuk)

A 13 MeV cyclotron has been developed by KIRAMS for radio-isotopes production such as F-18 and O-15 for positron emission tomography(PET). To characterize the cyclotron magnet precisely, a Hall probe mapping system with very high precise positioning mechanism in the Cartesian coordinate has been developed. Hall probe assembly was translated in two dimensions by two stepping motors at both sides of the Hall-probe-carrier to keep synchronously rotation sharing one step-pulse source for x-axis and one motor for y-axis. The data acquisition time had reduced to 60 minutes in full mapping by 'flying' mode. The accuracy of the measurement system is better than during the entire mapping process. In this paper the magnetic field measurement system for the cyclotron magnet is described, and measurement results are presented.



Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
21-1130 - The Bunch Compressor System for SIS18 at GSI

Peter Hülsmann, Martin Emmerling, Werner Gutowski, Gerald Hutter, Wolfgang Vinzenz (GSI, Darmstadt)

For bunch compression down to pulse durations of 50 ns, a dedicated rf system is under development for the SIS12/18 heavy ion synchrotron upgrade and will be described in this paper. Due to space restrictions in SIS12/18 the rf system consists of very short cavities which provide a very large voltage gradient (50 kV/m) at a very low frequency of approximately 800 kHz and rf final stages which provide a short rise time. The only possibilty to meet the requirements is the application of a cavity heavily inductively loaded by metallic alloy (MA) ring cores. This new rf system will be a prototype for the advanced acceleration and compression system needed in SIS100, which is the most important part for the proposed International Acceleration Facility at GSI. In order to gain experience with different MA ring core materials two of the four compressor cavities are loaded differently, which gives us an opportunity to learn the operational advantages of both materials. It is expected that the experimental results will support the final judgement for the future rf system in SIS100.



Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
22-1131 - Upgrading the AC Power Supply to the ISIS Main Magnet Circuit

Steve West, James Gray, Adrian Morris (CCLRC/RAL/ISIS, Chilton, Didcot, Oxon)

ISIS, situated at the Rutherford Appleton Laboratory (RAL) is the world?s most powerful pulsed neutron source. At the heart of the ISIS accelerator is a proton synchrotron which uses a ring of magnets connected in series and configured as a ?White Circuit?. The magnets are connected in series with capacitor banks so that they form a resonant circuit with a fundamental frequency of 50 Hz. The circuit allows the magnets to be fed with an AC current superimposed on a DC current. The AC is currently provided by a 1MVA Motor-Alternator set and it is now proposed to replace this by a solid state UPS (Uninterruptible Power Supply) system. Tests on a smaller 80kVA unit have shown that it is possible to control the magnet current with a modified UPS system in such a way that both the frequency, phase and output voltage are under the direct influence of the control system. This paper discusses the issues surrounding the upgrading of AC supply to the main magnets with a view to improving the system reliability, improving magnet current stability and reducing the risk of mains failure.



Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
23-1164 - Status of the Cooler Synchrotron Cosy-juelich

Bernd Lorentz (FZJ/COSY, Jülich), Ralf Eichhorn, Ralf Gebel, Herbert Schneider (FZJ, Julich), Ulf Bechstedt, Jürgen Dietrich, Andreas Lehrach, Rudolf Maier, Dieter Prasuhn, Alexander Schnase, Rolf Stassen, Hans Stockhorst, Raimund Tölle (FZJ/IKP, Jülich)

The cooler synchrotron COSY accelerates and stores unpolarized and polarized protons and deuterons in the momentum range between 300 MeV/c to 3.65 GeV/c. To provide high quality beams, an Electron Cooler at injection and a Stochastic Cooling System from 1.5 GeV/c up to maximum momentum are available. Vertically polarized proton beams with a polarization of more than 0.80 are delivered to internal and external experimental areas at different momenta. Externally, the maximum momentum is up to date restricted to approximately 3.4 GeV/c by the extraction elements installed in COSY. In 2003 deuteron beams with different combinations of vector and tensor polarization were made available for internal and external experiments. An rf dipole was installed, which is used to induce artificial depolarizing resonances. It can be used for an accurate determination of the momentum of the stored beams. The status of the cooler synchrotron COSY is presented and future plans are discussed.



Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
24-1197 - A Double Electrostatic Storage Ring, DESIREE

Karl-Gunnar Rensfelt, Lars Bagge, Mikael Blom, Håkan Danared, Leif Liljeby, Andras Paal, Ansgar Simonsson, Örjan Skeppstedt (MSL, Stockholm), Henrik Cederquist, Jens-Peter Jensen, Mats Larsson, Sven Mannervik, Henning Schmidt, Kjell Schmidt (Stockholm University, Stockholm)

The advantages of storage rings with only electrostatic elements were first demonstrated by ELISA in Aarhus and later in other places. At MSL and Fysikum at Stockholm University the ideas have been developed further in the Double Electrostatic Storage Ion Ring ExpEriment, DESIREE. Beams of negative and positive ions will be merged in a common straight section of the rings so that low energy collisions can be studied. Furthermore the rings will be cooled to 10 - 20 K in order to relax internal excitations in circulating molecules. A design report can be found at www.msl.se. The project is now (January 2004) almost fully financed and the final design work has recently been started. The paper will shortly review the physics programme and describe the status of the design work.

Knut and Alice Wallenberg Foundation, Stockholm

The Swedish Research Council



Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
25-1234 - Nonlinear Effects Studies for a Large Acceptance Collector Ring

Alexei Dolinskii, Karl Beckert, Peter Beller, Bernhard Franzke, Fritz Nolden, Markus Steck (GSI, Darmstadt)

A large acceptance collector ring (CR) is designed for fast cooling of rare isotope and antiproton beams, which will be used for nuclear physics experiments in the frame of the new international accelerator facility recently proposed at GSI. This contribution describes the linear and non-linear optimisation used to derive a lattice solution with good dynamic behaviour simultaneously meeting the demands for very fast stochastic cooling for two optical modes (for rare isotope and antiproton beams). Effects due to non-linear field contributions of the magnet field in dipoles and quadrupoles are very critical in this ring. Using a single particle dynamics approach, the major magnetic non-linearities of the CR are studied. We discuss the particle dynamics of the dipole and quadrupole fringe fields and the their influence on the dynamic aperture and on the tune. Additionally, the CR will be operated at the transition energy (isochronous mode) for time of flight (TOF) mass spectrometery of short-lived radioactive ions. For this mode a specific correction scheme is required to reach a high degree of isochronism over a large acceptance.



Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
26-1235 - Rare and Exotic Nuclei Ion Beam on the Base of FLNR JINR Cyclotron Complex

Georgy Gulbekyan (JINR, Dubna, Moscow Region)

Cyclotrons U400 and U400M complited by 14.5 GHz ECR ion sources. yclotron U400 are used for acceleration of rare isotopes as 48Ca with beam intensity on the target 1.3 ρμa as the postaccelerater for ion beam exotic nuclei as 6He and 8He. Cyclotron U400M are used for acceleration of light ions as 7Li and 11Be with intensity up to 10 ρμa for production 6He and 8He nuclei on the Be target.



Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
27-1284 - Status of the Booster Injector for the Duke FEL Storage Ring

Stepan Mikhailov, Matthew D. Busch, Mark Emamian, Steve Hartman, Jingyi LI, Vladimir N Litvinenko, Igor Pinayev, Victor Popov, Gary Swift, Patrick Wallace, Ping Wang, Y. K. Wu (DU/FEL, Durham, North Carolina), Nikolai Gavrilov, Yuri Matveev, Dmitry Shvedov, Nikolay Vinokurov, Pavel Vobly (BINP, Novosibirsk)

This paper presents the current status of the booster synchrotron for the Duke FEL storage ring. The booster will provide full energy injection into the storage ring in a wide energy range from 0.27 to 1.2 GeV. When operating the Duke FEL storage ring as the High Intensity Gamma Source (HIGS) to produce gamma photons above 20 MeV with Compton scattering, continuous electron loss occurs. The top-off mode operation of the booster injector will enable the continuous operation of the HIGS facility by replenishing the lost electrons. The design requirement for a very compact booster with the single bunch extraction capability remains a challenge for the machine development. Presently, the booster project is entering the construction phase. The fabrication of the magnetic system, vacuum system, injection and extraction kickers is presently under way in the Budker Institute of Nuclear Physics, Russia. The diagnostic and control system is being developed in the FEL lab, Duke University. The installation and commissioning of the booster synchrotron is planned for 2005.

This work is supported by DOE and by the Dean of Natural Sciences (Duke University)

Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
28-1306 - Challenges for Vertical Injection and Extraction in the Duke Booster Synchrotron

Stepan Mikhailov, Jingyi LI, Igor Pinayev, Y. K. Wu (DU/FEL, Durham, North Carolina), Yuri Matveev, Dmitry Shvedov (BINP, Novosibirsk)

The full energy booster injector for the Duke FEL storage ring is entering the construction phase. The booster is designed to provide continuous injection in the top-off mode. The injected beam energy from the linac pre-injector is 270 MeV and the extraction energy of the booster varies from 270 MeV to 1.2 GeV. The designed maximum current capability of the booster is 4 nC/sec. The booster is also designed to provide the single bunch extraction capability. For the single bunch extraction a kicker with a pulse duration of 11 nsec has been developed, which imposes a strict limitation on the maximum kick angle. The compactness of the booster ring propelled us to choose a vertical injection/extraction scheme with a relatively high vertical beta function of 25 m at kickers and septum magnets. The major disadvantage of such a scheme is a small vertical acceptance for injection and extraction. The paper presents lattice solutions and technical solutions for achieving vertical injection and the single bunch extraction for the booster.

This work is supported by DOE and by the Dean of Natural Sciences (Duke University)

Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
29-1329 - Measuring and Correcting the Vertical Beam Excursions in the AGOR Cyclotron

Mariet Anna Hofstee, Sytze Brandenburg (KVI, Groningen)

Large-scale vertical excursions have been observed in the AGOR cyclotron for light ionbeams at energies close to the focussing limit (E/A =200 Q/A MeV per nucleon). With increasing radius the beam gradually moves down out of the geometrical median plane by several mm, leading to internal beamlosses. It was concluded that this effect is caused by a vertical alignment error of the coils combined with the weak vertical focussing for the beams concerned. Moving the main coils by a total of 0.37 mm has significantly improved the situation at large radii, but results in internal beamlosses for certain beams at small radii due to a large upward excursion. A systematic study of the vertical beam dynamics as a function of beam particle and energy will be presented. Possible causes and solutions will be discussed.

Rijks Universiteit Groningen and Stichting FOM, Utrecht

Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
30-1333 - Luminosity Considerations for Internal and External Experiments @ COSY

Andreas Lehrach, Ulf Bechstedt, Jürgen Dietrich, Ralf Eichhorn, Ralf Gebel, Bernd Lorentz, Rudolf Maier, Dieter Prasuhn, Herbert Schneider, Rolf Stassen, Hans Stockhorst, Raimund Tölle (FZJ/IKP, Jülich), Alexander Schnase (J-PARC /JAERI, Tokai-Mura, Naka-Gun, Ibaraki-Ken)

The future physics program at the Cooler-Synchrotron COSY in Jülich requires intense beams to provide high luminosities up to 10^32cm^-2s^-1 for internal and external experiments. In 2003 the number of unpolarized protons could significantly be increased up to the theoretical space charge limit of COSY. This was achieved by careful study and adjustment of all subsystems in the accelerator chain of COSY. The intensities for polarized proton beams are at best an order of magnitude lower compared to one for unpolarized beams, depending on the beam current provided the injector cyclotron. Still there is some potential for further enhancement of polarized beam intensities. In this paper, luminosity considerations for polarized and unpolarized beams at COSY are presented taking into account different machine cycles and operation modes for internal and external experimental set-ups.



Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
31-1334 - DAFNE Operation with the FINUDA Experiment.

Catia Milardi (INFN/LNF, Frascati (Roma))

DAFNE operation restarted in September 2003, after a six months shut-down for the installation of FINUDA, a magnetic detector dedicated to the study of hypernuclear Physics. FINUDA is the third experiment running, in sequence, at DAFNE and operates while keeping on place the other detector KLOE. During the shut-down both the Interaction Regions have been equipped with remotely controlled rotating quadrupoles in order to operate at different solenoid fields. Among many other har ware upgrades one of the most significant is the reshaping of the wiggler pole profile to improve the field quality and the machine dynamic aperture. Commissioning of the collider in the new configuration has been completed in short time. The peak luminosity delivered to FINUDA has reached 6 1031 s-1 cm-2, with a daily integrated value exceeding 3 pb-1.



Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
32-1540 - System Parameters for Magnets and Power Supplies

William J. McGahern, Sorin Badea, F. M. Hemmer, Robert Lambiase, George Mahler, Chien Pai, Charlie Pearson, Jim Rank, Deepak Raparia, Jon Sandberg, Joseph Tuozzolo (BNL, Upton, Long Island, New York)

The Spallation Neutron Source (SNS), currently under construction at Oak Ridge, Tennessee, is a collaborative effort of six U.S. Department of Energy partner laboratories. With over 312 magnets and 251 power supplies that comprise the beam transport lines and the accumulator ring, it is a challenge to maintain a closed loop on the variable parameters that are integral to these two major systems. This paper addresses the input variables, responsibilities and design parameters used to define the SNS magnet and power supply systems.

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



Type of presentation requested: Poster

Classification: [A04] Low- and Intermediate-Energy Circular Accelerators
33-244 - An Electrostatic Quadrupole Doublet with an Integrated Steerer

Carsten Peter Welsch, Manfred Grieser, Joachim Ullrich (MPI-K, Heidelberg), Christian Glaessner (IAP, Frankfurt-am-Main)

Electrostatic storage rings have proven to be a valuable tool for atomic and molecular physics Due to the mass independence of the fields in the bending and focusing elements, different kinds of ions with the same charge/energy ratio from light protons to very heavy biomolecules, can be stored with the same field setup. The transverse dimensions of the circulating beam are controlled by electrostatic quadrupole doublets or triplets. It is essential that the fields in these lenses can be adjusted independently one from another to allow an exact control of the stored ions. In this paper, first an overview of the principle of electrostatic lenses is given. After a short discussion of fringe field effects, the results of field calculations are presented and the final layout of an electrostatic quadrupole doublet with an integrated steerer as it will be used in future electrostatic storage rings in Frankfurt and Heidelberg is discussed.



Type of presentation requested: Poster

Classification: [A07] Electrostatic Accelerators
34-435 - Compact Electrostatic Tandem Accelerator Based Neutron Source for the Medicine

Valery Shirokov, Alexey Babkin, Pavel Bykov, Gennady Kraynov, Gregory Silvestrov, Yuri Tokarev (BINP, Novosibirsk), Mikhail Bokhovko, Oleg Kononov, Victor Kononov (IPPE, Kaluga Region)

Status of original heavy hydrogen ion electrostatic accelerator-tandem is described. Potential electrodes with vacuum insulation organize tract for accelerating ion beam before and after gas stripper, located inside the high voltage electrode. There are no accelerating tubes in the tandem proposed. 20 kHz, 10 kW, 500 kV compact sectioned rectifier is a high voltage source. Both the geometry of neutron source and results of the rectifier testing are presented. Estimation of yield and space-energy distribution of neutron, as a result of nuclear reactions produced by heavy hydrogen ion in beryllium or carbon targets are given. Result of Monte-Carlo simulation of neutron and photon transferring for these sources of neutron is the distribution of the absorbed dose incide phantom. Result of the simulation are compared with result of the experiment. The possibility of use of this neutron source for the neutron or neutron capture therapy is discussed too.



Type of presentation requested: Poster

Classification: [A07] Electrostatic Accelerators
35-535 - CSR - a Cryogenic Storage Ring at MPI-K

Carsten Peter Welsch, Manfred Grieser, Dirk Schwalm, Joachim Ullrich, Robert Von Hahn, Andreas Wolf (MPI-K, Heidelberg), Daniel Zajfman (Weizmann Institute of Science, Rehovot)

A small cryogenic storage ring is planned to be developed at MPI-K, Heidelberg. The energy in the machine will be variable from 300 keV > down to 20 keV. Electron cooling will be applied to produce a high quality ion beam. The ring shall accommodate slow, vibrationally and rotationally cooled molecular ions and highly charged ions from the EBIT ion source. Moreover, it will serve as a test facility for the low-energy antiproton ring planned within the FLAIR collaboration to be installed at the future GSI facility. A number of technological challenges have to be handled: Especially highly charged ions require a vacuum in the order below 10-13 mbar to achieve reasonable lifetimes. Therefore - and for enabling experiments with rotationally cold molecules - the complete machine will be cooled down to below 10 K. Moreover, experiments with reaction microscopes to determine the full kinematics of ion- (antiproton-) atom or molecule collisions require a bunched operation with a bunch length below 2 ns. The optical elements of the machine and the lattice functions are given and first ideas about the vacuum chamber design are described in this paper.



Type of presentation requested: Poster

Classification: [A07] Electrostatic Accelerators
36-539 - Ultra-low Energy Antiprotons at FLAIR

Carsten Peter Welsch, Manfred Grieser, Joachim Ullrich (MPI-K, Heidelberg)

The Future Accelerator Facility for Beams of Ions and Antiprotons at Darmstadt will produce the highest flux of antiprotons in the world. So far it is foreseen to accelerate the antiprotons to high energies (3-15 GeV) for meson spectroscopy and other nuclear and particle physics experiments in the HESR (High Energy Storage Ring). Within the planned complex of storage rings, it is possible to decelerate the antiprotons to about 30 MeV kinetic energy, opening up the possibility to create low energy antiprotons. In the proposed FLAIR facility the antiprotons shall be slowed down in a last step from 300 keV to 20 keV in an electrostatic storage ring (USR) for various in-ring experiments as well as for their efficient injection into traps. In this energy range - especially if one thinks about realizing a real multi-purpose facility with not only antiprotons, but also various highly-charged radioactive ions to be stored and investigated - electrostatic storage rings have clear advantages compared to their magnetic counterparts. In case one envisions to even approach the eV range, electrostatic machines are the only possible choice. This contribution presents the layout and design parameters of the USR.


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