• M. Giovannozzi, R. Cappi, S.S. Gilardoni, M. Martini, E. Métral, R.R. Steerenberg
  CERN, Geneva
• A.-S. Müller
  FZK, Karlsruhe

• J.S. Berg
  BNL, Upton, Long Island, New York

Linear Non-Scaling FFAGs have, particularly for muon acceleration, a unique type of longitudinal motion. This longitudinal motion can be approximated by a parabolic dependence time-of-flight on energy. This motion can be described in dimensionless variables with two parameters. I describe the relationship between the parameters and the distortion of ellipses in longitudinal space. I discuss the relationship between the longitudinal acceptance and the time spent in the FFAG, the latter being especially relevant for decays in muon accelerators. I discuss what improvement one can expect to achieve by adding higher-harmonic RF systems to the accelerator.

• F. Noda, N. Hayashi, H. Hotchi, J. Kishiro, P.K. Saha, Y. Shobuda, K. Yamamoto
  JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• S. Machida, A.Y. Molodojentsev
  KEK, Ibaraki

• V.A. Shchepunov
  ORAU, Oak Ridge, Tennessee
• H. Wollnik
  JIHIR, Oak Ridge, Tennessee

A multi-pass time-of-flight (MTOF) mass separator is under development by the UNIRIB collaboration. The MTOF consists of two coaxial electrostatic mirrors, focusing lenses and auxiliary injection, extraction and separation elements. The injected ions having almost the same energy but different masses undergo hundreds or thousands of reflections between the mirrors. In the course of this periodic motion, the ions of different masses and hence velocities are spatially separated in longitudinal direction. The periodic motion in the MTOF has been investigated with a recently developed ray tracing program utilizing the canonical integration technique. Results of the performed numerical simulations are discussed. The simulations displayed nonlinear character of the ion’s behavior both in transverse and longitudinal phase spaces. The ion’s transverse stability and longitudinal isochronicity were the matters of primary attention. It is shown in particular that at transverse tunes of around q=0.75 the system can be adjusted to be isochronous up to at least the 3rd order of the ToF optical aberrations.

• M.-J. Yang
  Fermilab, Batavia, Illinois

• B. Doliwa, H. De Gersem, T. Weiland
  TEMF, Darmstadt

Maintaining the impedance budget is an important task in the planning of any new accelerator facility. While estimates from analytical computations and measurements play a central role in doing so, numerical calculations have become an important alternative today. On the basis of Finite Integration Theory, we have developed a simulation tool for the direct computation of coupling impedances in the frequency domain. After discussing the special features of our code as compared to commercial programs, we present our results for cases where coupling impedances have been obtained from another source, e.g. experiment. In particular, we consider the longitudinal and transverse impedances of the SNS extraction kicker and present investigations related to the injection/extraction system of the future heavy-ion synchrotron at GSI.

• J. Kamiya, T. Takayanagi
  JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• T. Kawakubo, S. Murasugi, E. Nakamura
  KEK, Ibaraki

• T. Takayanagi, Y. Irie, J. Kamiya
  JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• T. Kawakubo, I. Sakai
  KEK, Ibaraki

• H.S. Suh, H.S. Han, S.-H. Jeong, Y.G. Jung, H.-S. Kang, H.-G. Lee, K.-H. Park, C. K. Ryu
  PAL, Pohang, Kyungbuk

The PEFP(Proton Engineering Frontier Project) proton linac is designed to have two proton beam extraction lines at the 20-MeV and 100-MeV end. The 20-MeV extraction line is branched out into 5 beamlines by using the switching magnet. The magnet bends the proton beam by +20, +10, 0, -10, -20 degrees, respectively, and has an AC frequency of 5 Hz with a programmable ac power supply. It employs an H-shape, 0.45 T magnetic field, 0.5 m effective magnet length, 30x5 cm bore aperture. The pole shape is optimized for the field levels. Laminated steel of 0.5 mm is enough to suppress the eddy current effect in the yoke. This paper presents the magnet specification and primary design.

• D. Shuman, W. Barry, S. Prestemon, R.D. Schlueter, C. Steier, G.D. Stover
  LBNL, Berkeley, California

Stray field from an eddy current septum magnet adversely affects the circulating beam and can be reduced using several techniques. The stray field time history typically has a fast rise section followed by a long exponential decay section when pulsed with a half sine drive current. Changing the drive current pulse to a full sine has the effect of both reducing peak stray field magnitude by ~3x, and producing a quick decay from this peak to a lower field level which then has a similar long decay time constant as that from the half sine only drive current pulse. A method for tuning the second half sine (reverse) drive current pulse to eliminate the long exponential decay section is given.

• C. Pai, H. Hahn, H.-C. Hseuh, Y.Y. Lee, W. Meng, J.-L. Mi, D. Raparia, J. Sandberg, R.J. Todd, N. Tsoupas, J.E. Tuozzolo, D.S. Warburton, J. Wei, D. Weiss, W. Zhang
  BNL, Upton, Long Island, New York

Two extraction kicker magnet assemblies that contain seven individual pulsed magnet modules each will kick the proton beam vertically out of the SNS accumulator ring into the aperture of the extraction lambertson septum magnet. The proton beam then travels to the 1.4 MW SNS target assembly. The 14 kicker magnets and major components of the kicker assembly have been fabricated in BNL. The inner surfaces of the kicker magnets were coated with TiN to reduce the secondary electron yield. All 14 PFN power supplies have been built, tested and delivered to ORNL. Before final installation, a partial assembly of the kicker system with three kicker magnets was assembled to test the functions of each critical component in the system. In this paper we report the progress of the construction of the kicker components, the TiN coating of the magnets, the installation procedure of the magnets and the full power test of the kicker with the PFN power supply.

• J. Rank, Y.Y. Lee, W.J. McGahern, G. Miglionico, D. Raparia, N. Tsoupas, J.E. Tuozzolo, J. Wei
  BNL, Upton, Long Island, New York

In the Spallation Neutron Source, at Oak Ridge National Laboratory in Tennessee, multiple-stage injections to an accumulator ring increase intensity until a final extraction delivers the full proton beam to the target via transfer line. This extraction is achieved by a series of kicker elements and a thin septum Extraction Lambertson Septum Magnet. Here we discuss the lattice geometry, beam dynamics and optics, and the vacuum, electromagnetic and electromechanical design aspects of the SNS Extraction Lambertson Septum Magnet. Relevant datums are established. Beam optics is studied. Vector calculus is solved for pitch and roll angles. Fundamental magnet sections are depicted schematically. Coil, pole and yoke design calculations and electromagnetics optimization are presented.

• D. Raparia
  BNL, Upton, Long Island, New York

The Spallation Neutron Source (SNS) is a second generation pulsed neutron source (1.5 MW) and is presently in the sixth year of a seven-year construction cycle at Oak Ridge National Laboratory. The operation of the facility will begin in 2006. The most stringent requirement for the SNS accelerator complex is to allow hands-on maintenance. Operational experiences show that the most losses occur in the injection and extraction. SNS accumulator ring injection and extraction has been design with grate care to reduce uncontrolled losses. Injection systems consist of fast programmable kicker magnets and DC dump magnets to paint the beam in transverse phase space. Extraction systems consist of fast kicker magnets and a Lamberton magnet to extract beam in single turn. Paper will discuss design, construction and testing of these devices.

• C. Wang, V.P. Yakovlev
  Omega-P, Inc., New Haven, Connecticut
• J.L. Hirshfield
  Yale University, Physics Department, New Haven, CT
• T.C. Marshall
  Columbia University, New York

A novel dielectric structure is described for a two-beam wake field accelerator (WFA), which consists of three or four rectangular dielectric slabs positioned within a rectangular conducting pipe. This structure can be thought of as equivalent to two symmetric dielectric-lined three-zone rectangular waveguides, joined side-by-side. The design mode in the two-beam structure is the LSM-31 mode, a combination of two symmetric LSM-11 modes of the two three-zone waveguides. This two-channel mode can be employed to decelerate drive particles in one channel and accelerate test particles in the other. It is possible to find structure parameters that give a high ratio of acceleration gradient for the test beam, to deceleration gradient for the drive beam, of the order of 100.

• R. Filippini, E. Carlier, L. Ducimetière, B. Goddard, J.A. Uythoven
  CERN, Geneva

• J.A. Uythoven, G. Arduini, B. Goddard, D. Jacquet, V. Kain, M. Lamont, V. Mertens, A. Spinks, J. Wenninger
  CERN, Geneva
• Y.-C. Chao
  Jefferson Lab, Newport News, Virginia

• J. Wenninger, B. Goddard, V. Kain, J.A. Uythoven
  CERN, Geneva

• J. Wenninger, G. Arduini, B. Goddard, D. Jacquet, V. Kain, M. Lamont, V. Mertens, J.A. Uythoven
  CERN, Geneva
• Y.-C. Chao
  Jefferson Lab, Newport News, Virginia

• M. Giovannozzi, J. Morel
  CERN, Geneva

• J.A. Holmes, V.V. Danilov
  ORNL, Oak Ridge, Tennessee
• L.K. Jain
  UW/Physics, Waterloo, Ontario

Detailed studies of the transverse stability of the SNS ring have been carried out for realistic injection scenarios. For coasting beam models and single harmonic impedances, analytic and computational results including phase slip, chromaticity, and space charge are in excellent agreement. For the dominant extraction kicker impedance and bunched beams resulting from injection, computationally determined stability thresholds are significantly higher than for coasting beams. At this time, we have no analytic model to treat the bunched beam case, but we present a formulation that provides an approach to this problem.

• J.C. Dooling, F.R. Brumwell, G.E. McMichael, S. Wang
  ANL, Argonne, Illinois

The Intense Pulsed Neutron Source (IPNS) Rapid Cycling Synchrotron (RCS) accelerates 3.2x 10¹² protons from 50 MeV to 450 MeV in a single bunch (h=1) at 30 Hz. The rf frequency varies from 2.21 MHz to 5.14 MHz during the 14.2 ms acceleration interval. To maintain stability of the bunch, phase modulation is introduced to the rf at approximately twice the synchrotron frequency (synchrotron tune is 0.0014). This phase modulation causes a parametric quadrupole oscillation to develop in the bunch, and as this occurs, the bunch spectrum shows a significant increase in high frequency content. Without phase modulation, the beam experiences an instability which results in the loss of a large fraction of the charge 2-4 ms prior to extraction. It is unclear if the stability imparted to the beam by phase modulation comes from the quadrupole oscillation or from the high frequency excitation. A longitudinal tracking code is presently being modified to include amplitude and phase modulation of the bunch. The numerical analysis will be used to compare growth rates with those observed in the machine. The results of this analysis will be important as we introduce second harmonic rf with a new third cavity in the RCS later in 2005.

• J. Peters
  DESY, Hamburg

The HERA RF-Volume Source is the only source that delivers routinely a H – current of 40 mA without Cs. It has been running for years without interruption for maintenance. The production mechanism for H – ions in this type of source is still under discussion. Laser photodetachment measurements have been done at DESY in order to measure the H – distribution in the source. The measurements were done also under extraction conditions at high voltage. The dependency of the quality of the Hminus beam on the frequency was investigated. A frequency range of 1.65 – 9 Mhz was scanned and the emittance was measured for several Hminus currents up to 40 mA. The results of our investigations make further source improvements possible. Recently currents of 60 mA were reached.

• M. Cavenago
  INFN/LNL, Legnaro, Padova
• V. Antoni, F. Sattin
  CNR/RFX, Padova
• A. Tanga
  MPI/IPP, Garching

Effects of plasma meniscus on the emittance in negative ion source proposed for spallation sources or neutral beam injectors (NBI) for tokamaks are particularly interesting to study with fluid models because: 1) at least three different charged fluid can be recognised: the thermalized and fully magnetized electrons; the slightly magnetized and roughly thermalized positive ions; the negative ions, typically formed within few cm from meniscus; 2) different implementation of the magnetic filter system need to be compared; 3) optimization of electron dump and outlet electrode strongly depends on plasma meniscus contact point. With reasonable assumption on system geometry, 2D and 3D charged fluid quation for the selfconsistent electrostatic field can be written and effect of grid aperture is investigated. Moreover, these equations are easily implemented into a multiphysics general purpose program. Preliminary results are described, and compared to existing codes.

• I.-S. Hong, Y.-S. Cho, S.-H. Han
  KAERI, Daejon

Duoplasmatron type ion source with 50keV proton beam has been constructed and stably operated as the injector for Proton Engineering Frontier Project(PEFP). In DC operation, the beam current of 50mA with 50kV extraction voltage is routinely obtained. However, the pulsed operation mode of the ion source also has been considered to reduce beam induced damage at the entrance of RFQ. A high voltage pulse switch is connected between accelerating electrode and ground electrode for this purpose. The detailed scheme on the focusing of the pulsed proton beam with space charge compensation is in progress. Beam profile and current in front of RFQ will be measured by DCCT and optical measuring tools.

• J. Qiang, D. Leitner, D.S. Todd
  LBNL, Berkeley, California

The driver linac of the proposed Rare Isotope Accelerator (RIA) requires a great variety of high intensity, high charge state ion beams. In order to design and optimize the low energy beam line optics of the RIA front end, we have developed a new parallel three-dimensional model to simulate the low energy, multi-species beam transport from the ECR ion source extraction region to the focal plane of the analyzing magnet. A multi-section overlapped computational domain has been used to break the original transport system into a number of independent subsystems. Within each subsystem, macro-particle tracking is used to obtain the charge density distribution in this subdomain. The three-dimensional Poisson equation is solved within the subdomain and particle tracking is repeated until the solution converges. Two new Poisson solvers based on a combination of the spectral method and the multigrid method have been developed to solve the Poisson equation in cylindrical coordinates for the beam extraction region and in the Frenet-Serret coordinates for the bending magnet region. Some test examples and initial applications will also be presented.

• G.A. Westenskow, D.P. Grote, E. F. Halaxa
  LLNL, Livermore, California
• F.M. Bieniosek, J.W. Kwan
  LBNL, Berkeley, California

To provide compact high-brightness heavy-ion beams for Heavy Ion Fusion (HIF) accelerators, we have been experimenting with merging multi-beamlets in an injector which uses an RF plasma source. In an 80-kV 20-microsecond experiment, the RF plasma source has produced up to 5 mA of Ar+ in a single beamlet. An extraction current density of 100 mA/cm2 was achieved, and the thermal temperature of the ions was below 1 eV. More than 90% of the ions were in the Ar+ state, and the energy spread from charge exchange was found to be small. We have tested at full voltage gradient the first 4 gaps of a 61-beamlet injector design. Einzel lens were used to focus the beamlets while reducing the beamlet to beamlet space charge interaction. We will report on a converging 119 multi-beamlet source. Although the source has the same optics as a full 1.6 MV injector system, the test will be carried out at 400 kV due to the test stand HV limit. We will measure the beam’s emittance after the beamlets are merged and have been transported through an electrostatic quadrupole. Our goal is to confirm the emittance growth and to demonstrate the technical feasibility of building a driver-scale HIF injector.

• D.C. Faircloth, R. Sidlow, M. Whitehead, T.W. Wood
  CCLRC/RAL/ISIS, Chilton, Didcot, Oxon

The development of H^- ion sources with performances exceeding those achieved today is a key requirement for the next generation of high power proton accelerators. The Penning surface plasma source development program at ISIS is now well established. To allow different ion source designs to be fully tested, the ability to vary the Penning field is required. Until now the Penning field has been generated by the same magnetic circuit that creates the analyzing field, giving no practical way of altering the Penning field alone. This paper describes the infrastructure changes required to allow the Penning field to be independently varied. The effect the Penning field has on beam current, emittance and discharge stability are discussed.

• V. Variale, A. Boggia, T. Clauser, A. Rainò, V. Valentino
  INFN-Bari, Bari
• P.A. Bak, M. A. Batazova, G.I. Kuznetsov, S. Shiyankov, B.A. Skarbo
  BINP SB RAS, Novosibirsk
• G. Verrone
  Università e Politecnico di Bari, Bari

The "charge state breeder" BRIC (BReeding Ion Charge) is based on an EBIS source and it is designed to accept Radioactive Ion Beam (RIB) with charge +1, in a slow injection mode, to increase their charge state up to +n. BRIC has been developed at the INFN section of Bari (Italy) during these last 3 years with very limited funds. Now, it has been assembled at the LNL (Italy) where are in progress the first tests as stand alone source. The new feature of BRIC, with respect to the classical EBIS, is given by the insertion, in the ion drift chamber, of a Radio Frequency (RF) Quadrupole aiming to filtering the unwanted elements and then making a more efficient containment of the wanted ions. In this contribution, the measurements of the selective effect on the ion charge state containement of the RF quadrupole field, applied on the ion chamber, will be reported and discussed. The ion charge state analisys of the ions trapped in BRIC seem confirm, as foreseen by simulation results carried out previously, that the selective containment can be obtained. A modification of the collector part to improve the ion extraction of BRIC will be also presented and shortly discussed.

• D.S. Todd, D. Leitner, C.M. Lyneis, J. Qiang
  LBNL, Berkeley, California
• D.P. Grote
  LLNL, Livermore, California

The next-generation superconducting ECR ion source VENUS serves as the prototype injector ion source for the linac driver of the proposed Rare Isotope Accelerator (RIA). The high-intensity heavy ion beams required by the RIA driver linac present significant challenges for the design and simulation of an ECR extraction and low energy ion beam transport system. Extraction and beam formation take place in a strong (up to 3T) axial magnetic field, which leads to significantly different focusing properties for the different ion masses and charge states of the extracted beam. Typically, beam simulations must take into account the contributions of up to 30 different charge states and ion masses. Two three-dimensional, particle-in-cell codes developed for other purposes, IMPACT and WARP, have been adapted in order to model intense, multi-species DC beams. A discussion of the differences of these codes and the advantages of each in the simulation of the low energy beam transport system of an ECR ion source is given. Direct comparisons of results from these two codes as well as with experimental results from VENUS are presented.

• T. Tanaka, H. Hama, F. Hinode, M. Kawai
  LNS, Sendai
• A. Miyamoto
  HSRC, Higashi-Hiroshima
• K. Shinto
  Tohoku University, Sendai

• A. Seryi
  SLAC, Menlo Park, California

• S. Passarello, G. Cuttone, G. Gallo, D. Garufi, A. Grmek, G. Manno, M. Re, E. ZappalÃ
  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.

• Y. Muttoni, J.-P. Corso, R. V. Valbuena
  CERN, Geneva

• S.-H. Jeong, H.S. Han, Y.G. Jung, H.-S. Kang, H.-G. Lee, K.-H. Park, C. K. Ryu, H.S. Suh
  PAL, Pohang, Kyungbuk
• H.H. Lee
  UU, Gyeongju

The 100-MeV PEFP proton linac has two proton beam extraction lines for user’ experiment. Each extraction line has 5 beamlines and has 5 Hz operating frequency. An AC switching magnet is used to distribute the proton beam to the 5 beamlines, An AC switching magnet is powered by PWM-controlled bipolar switching-mode converters. This converter is designed to operate at ±350A, 5 Hz programmable step output. The power supply is employed IGBT module and has controlled by a DSP (Digital Signal Process). This paper describes the design and test results of the power supply.

• I.V. Khodak, V.A. Kushnir
  NSC/KIPT, Kharkov

• V.P. Yakovlev, O.A. Nezhevenko
  Omega-P, Inc., New Haven, Connecticut
• J.L. Hirshfield
  Yale University, Physics Department, New Haven, CT

High-power ultra-fast, electrically-controlled switches based on ferroelectric elements for accelerator applications in the centimeter and millimeter wavelength ranges are discussed. Examples of fast switches and phase shifters for pulse compression and power distribution systems at X– and Ka- band are presented. It is shown that such proposed switch designs based on modern ferroelectric materials allow the generation of pulsed power of hundreds of MW’s in both the centimeter and millimeter wave ranges.

• D. Teytelman
  SLAC, Menlo Park, California

The RF system of the PEP-II collider uses two fast feedback loops around each klystron and set of cavities. These loops reduce the impedance of the fundamental mode of the accelerating cavities seen by the beam, and are necessary to reduce the growth rates of longitudinal modes within the RF system bandwidth. Operation of the accelerator at high beam currents is very sensitive to the configuration of the low-level RF feedback loops. There are 7 loop control parameters that strongly influence the stability of the feedback loops and the achieved level of longitudinal impedance reduction. Diagnostic techniques for the analysis of the RF feedback via closed-loop system transfer function measurements will be presented. The model is fit to the measured closed-loop transfer function data and the extracted parameters are then used to calculate optimal tuning and corrections to the loop control elements in the physical channel. These techniques allow fine-tuning of RF feedback with stored beam as well as diagnosis of mis-configured or malfunctioning elements of the system. Results from PEP-II operation will be presented to illustrate the techniques and their applications.

• M. Yoshii, S. Anami, E. Ezura, K. Hara, Y. Hashimoto, C. Ohmori, A. Takagi, M. Toda
  KEK, Ibaraki
• M. Nomura, A. Schnase, F. Tamura, M. Yamamoto
  JAERI, Ibaraki-ken

• J. Guo, S.G. Tantawi
  SLAC, Menlo Park, California

In this paper, we present the recent results of our research on the high power ultra-fast silicon RF switches. This switch is composed of a group of PIN diodes on a high purity SOI (silicon on oxide) wafer. The wafer is inserted into a cylindrical waveguide under T·10⁰¹ mode, performing switching by injecting carriers into the bulk silicon. Our current design is using a CMOS compatible process and the fabrication is accomplished at SNF (Stanford Nanofabrication Facility). This design is able to achieve sub-100ns switching time, while the switching speed can be improved further with 3-D device structure and faster circuit. Power handling capacity of the switch is at the level of 10MW. The switch was designed for active X-band RF pulse compression systems - especially for NLC, but it is also possible to be modified for other applications and other frequencies such as L-band.

• M.-H. Wang, H.-P. Chang, J. Chen, J.-R. Chen, K.-T. Hsu, C.-C. Kuo, G.-H. Luo
  NSRRC, Hsinchu

• M. Kumada
  NIRS, Chiba-shi
• B.I. Grishanov, E.B. Leivichev, V.V. Parkhomchuk, F.V. Podgorny, S. Rastigeev, V.B. Reva, A.N. Skrinsky, V.A. Vostrikov
  BINP SB RAS, Novosibirsk

• V. Auslender, A.A. Bryazgin, V.G. Cheskidov, B.L. Faktorovich, V. Gorbunov, I.V. Gornakov, V.E. Nekhaev, A.D. Panfilov, A.V. Sidorov, V.O. Tkachenko, A.F.A. Tuvik, L.A. Voronin
  BINP SB RAS, Novosibirsk

• J.W.  Staples, R. Keller, A. Sessler
  LBNL, Berkeley, California
• W. Chou
  Fermilab, Batavia, Illinois
• P.N. Ostroumov
  ANL, Argonne, Illinois

Accelerator-driven High-Energy Density Physics experiments require typically 1 nanosecond, 1 microcoulomb pulses of mass 20 ions accelerated to several MeV to produce eV-level excitations in thin targets, the "warm dense matter" regime. Traditionally the province of induction linacs, RF-based acceleration may be a viable alternative with recent breakthroughs in accelerating structures and high-field superconducting solenoids. A reference design for an RF-based accelerator for HEDP research is presented using 15 T solenoids and multiple-gap RF structures configured with either multiple parallel beams (combined at the target) or a single beam and a small stacking ring that accumulates 1 microcoulomb of charge. In either case, the beam is ballistically compressed with an induction linac core providing the necessary energy sweep and injected into a plasma-neutralized drift compression channel resulting in a 1 mm radius beam spot 1 nanosecond long at a thin foil or low-density target.

• K. Shinto, S. Kitajima, M. Sasao, H. Sugawara, Takenaga, M. Takenaga, S. Takeuchi
  Graduate School of Engineering, Tohoku University, Sendai
• O. Kaneko, M. Nishiura
  NIFS, Gifu
• S. Kiyama
  AIST, Tsukuba
• M. Wada
  Doshisha University, Graduate School of Engineering, Kyoto

*M. Sasao et al., Proc. of PAC99, pp. 1306-1308. **M. Sasao et al., Rev. Sci. Instr. Vol.69, pp.1063-1065 (1998).

• L. Ducimetière
  CERN, Geneva

• W. Zhang, J. Sandberg
  BNL, Upton, Long Island, New York
• R.I. Cutler
  ORNL, Oak Ridge, Tennessee
• L. Ducimetière, T. Fowler, V. Mertens
  CERN, Geneva
• T. Kawakubo, Y. Shirakabe
  KEK, Ibaraki

The pulsed power technology has been applied in particle accelerators and storage rings for over four decades. It is most commonly used in injection, extraction, beam manipulation, source, and focusing systems. These systems belong to the class of repetitive pulsed power. In this presentation, we review and discuss the history, present status, and future challenge of pulsed power applications in high intensity proton accelerators and storage rings.

• C.C. Jensen, G. E. Krafczyk
  Fermilab, Batavia, Illinois

This system extracts up to 9.6 us of 120 GeV beam every 1.87 seconds for the NuMI beamline neutrino experiments. A pulse forming network consisting of two continuous wound coils and 68 capacitors was designed and built to drive three kicker magnets. The field stability requirement is better than ± 1% with a field rise time of 1.6 us. New kicker magnets were built based on the successful traveling wave magnets built for the Main Injector. Two of these magnets, which have a propagation time of 550 ns, are in series making the risetime of the pulser a serious constraint. A forced cooling system using Fluorinert® was designed for the magnet termination resistors to maintain the field flatness and amplitude stability. The system has been commissioned and early results will be presented.

• M. Yoshioka, H. Kobayashi, T. Oogoe, Y. Takeuchi, Y. Watanabe
  KEK, Ibaraki
• Y. Kuniyasu
  MELCO SC, Tsukuba
• H. Oki, Y. Takiyama
  ,

J-PARC comprises a 400 MeV linac (181 MeV at the first stage), a 3 GeV rapid-cycling synchrotron and a 50 GeV synchrotron (Main Ring), which will provide high power proton beam to the material and life science facility, the neutrino facility and the nuclear and particle physics experimental hall. The installation of the accelerator components for the Main Ring will be started on mid. 2005 and the beam commissioning is scheduled in end of 2007. This paper describes the installation scenario of the accelerator components into the main ring tunnel and the development of radiation maintenance scenario for the beam injection and ejection systems.

• V. Kain, B. Goddard, R. Schmidt, J. Wenninger
  CERN, Geneva

• H.-C. Hseuh, M. Blaskiewicz, P. He, Y.Y. Lee, C. Pai, D. Raparia, R.J. Todd, L. Wang, J. Wei, D. Weiss
  BNL, Upton, Long Island, New York
• S. Henderson
  ORNL, Oak Ridge, Tennessee

The inner surfaces of the 248 m SNS accumulator ring vacuum chambers are coated with ~100 nm of titanium nitride (TiN) to reduce the secondary electron yield (SEY) of the chamber walls. All the ring inner surfaces are made of stainless or inconel, except those of the injection and extraction kickers. Ceramic vacuum chambers are used for the 8 injection kickers to avoid shielding of a fast-changing kicker field and to reduce eddy current heating. The internal diameter was coated with Cu to reduce the beam coupling impedance and provide passage for beam image current, and a TiN overlayer to reduce SEY. The ferrite surfaces of the 14 extraction kicker modules were coated with TiN to reduce SEY. Customized masks were used to produce coating strips of 1 cm x 5 cm with 1 to 1.5 mm separation among the strips. The masks maximized the coated area to more than 80%, while minimizing the eddy current effect to the kicker rise time. The coating method, as well as the physical and electromagnetic properties of the coatings for both types of kickers will be summarized, with emphasis on the effect to the beam and the electron cloud buildup.

†Corresponding author email: hseuh@bnl.gov.

• R.J. Todd, P. He, H.-C. Hseuh, D. Weiss
  BNL, Upton, Long Island, New York

The inner surfaces of the 248 m Spallation Neutron Source (SNS) accumulator ring vacuum chambers are coated with ~100 nm of titanium nitride (TiN) to reduce the secondary electron yield (SEY) of the chamber walls. There are approximately 100 chambers and kicker modules, some up to 5 m in length and 36 cm in diameter, coated with TiN. The coating is deposited by means of reactive DC magnetron sputtering using a cylindrical magnetron with internal permanent magnets. This cathode configuration generates a deposition rate sufficient to meet the required production schedule and produces stoichiometric films with good adhesion, low SEY and acceptable outgassing. Moreover, the cathode magnet configuration allows for simple changes in length and has been adapted to coat the wide variety of chambers and components contained within the arc, injection, extraction, collimation and RF regions. Chamber types, quantities and the cathode configurations used to coat them are presented herein. A brief summary of the salient coating properties is given including the interdependence of SEY as a function of surface roughness and its effect on outgassing. Limitations of this coating method are also discussed.

• H. Hayano, S. Araki, H. Hayano, Y. Higashi, Y. Honda, K.-I. Kanazawa, K. Kubo, T. Kume, M. Kuriki, S. Kuroda, M. Masuzawa, T. Naito, T. Okugi, R. Sugahara, T. Tauchi, N. Terunuma, N. Toge, J.U. Urakawa, V.V. Vogel, H. Yamaoka, K. Yokoya
  KEK, Ibaraki
• I.V. Agapov, G.A. Blair, G.E. Boorman, J. Carter, C.D. Driouichi, M.T. Price
  Royal Holloway, University of London, Surrey
• D.A.-K. Angal-Kalinin, R. Appleby, J.K. Jones, A. Kalinin
  CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
• P. Bambade
  LAL, Orsay
• K.L.F. Bane, A. Brachmann, T.M. Himel, T.W. Markiewicz, J. Nelson, N. Phinney, M.T.F. Pivi, T.O. Raubenheimer, M.C. Ross, R.E. Ruland, A. Seryi, C.M. Spencer, P. Tenenbaum, M. Woodley
  SLAC, Menlo Park, California
• S.T. Boogert, A. Liapine, S. Malton
  UCL, London
• H.-H. Braun, D. Schulte, F. Zimmermann
  CERN, Geneva
• P. Burrows, G.B. Christian, S. Molloy, G.R. White
  Queen Mary University of London, London
• J.Y. Choi, J.Y. Huang, H.-S. Kang, E.-S. Kim, S.H. Kim, I.S. Ko
  PAL, Pohang, Kyungbuk
• S. Danagoulian
  North Carolina A&T State University, Greensboro, North Carolina
• N. Delerue, D.F. Howell, A. Reichold, D. Urner
  OXFORDphysics, Oxford, Oxon
• J. Gao, W. Liu, G. Pei, J.Q. Wang
  IHEP Beijing, Beijing
• B.I. Grishanov, P.L. Logachev, F.V. Podgorny, V.I. Telnov
  BINP SB RAS, Novosibirsk
• J.G. Gronberg
  LLNL, Livermore, California
• Y. Iwashita, T. Mihara
  Kyoto ICR, Uji, Kyoto
• M. Kumada
  NIRS, Chiba-shi
• S. Mtingwa
  North Carolina University, Chapel Hill, North Carolina
• O. Napoly, J. Payet
  CEA/DSM/DAPNIA, Gif-sur-Yvette
• T.S. Sanuki, T.S. Suehara
  University of Tokyo, Tokyo
• T. Takahashi
  Hiroshima University, Higashi-Hiroshima
• E.T. Torrence
  University of Oregon, Eugene, Oregon
• N.J. Walker
  DESY, Hamburg

• B. Parker, M. Anerella, J. Escallier, M. Harrison, P. He, A.K. Jain, A. Marone, K.-C. Wu
  BNL, Upton, Long Island, New York
• T.W. Markiewicz, T.V.M. Maruyama, Y. Nosochkov, A. Seryi
  SLAC, Menlo Park, California

We present a compact superconducting final focus (FF) magnet system for the ILC based on recent BNL direct wind technology developments. Direct wind gives an integrated coil prestress solution for small transverse size coils. With beam crossing angles more than 15 mr, disrupted beam from the IP passes outside the coil while incoming beam is strongly focused. A superconducting FF magnet is adjustable to accommodate collision energy changes, i.e. energy scans and low energy calibration runs. A separate extraction line permits optimization of post IP beam diagnostics. Direct wind construction allows adding separate coils of arbitrary multipolarity (such as sextupole coils for local chromaticity correction). In our simplest coil geometry extracted beam sees significant fringe field. Since the fringe field affects the extracted beam, we also study advanced configurations that give either dramatic fringe field reduction (especially critical for gamma-gamma colliders) or useful quadrupole focusing on the outgoing beam channel. We present prototype coil winding test results and discuss our progress toward an integrated FF solution that addresses important machine detector interface issues.

• R.W. Helms, D. L. Rubin
  Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York

Current specifications for the International Linear Collider call for bunch trains hundreds of kilometers in length. We describe a scheme for manipulating a compressed bunch train in the damping ring using RF deflectors and multiple transfer lines. The concept is demonstrated in the design of a 4 km damping ring that circulates 2800 bunches spaced 4 ns apart, and we show that injection and extraction of individual bunches is possible with conventional kickers requiring rise/fall times of only 16 ns. The performance and stability of the 4 km damping ring is evaluated and compared with existing machines.

• Y. Nosochkov, K. C. Moffeit, A. Seryi, M. Woods
  SLAC, Menlo Park, California
• R. Arnold
  University of Massachusetts, Amherst
• W.P. Oliver
  Tufts University, Medford, Massachusetts
• B. Parker
  BNL, Upton, Long Island, New York
• E.T. Torrence
  University of Oregon, Eugene, Oregon

One of the two ILC Interaction Regions will have a large horizontal crossing angle which would allow to extract the spent beams in a separate beam line. In this paper, the extraction line design for 20 mrad crossing angle is presented. This beam line transports the primary e+/e^- and beamstrahlung photon beams from the IP to a common dump, and includes diagnostic section for energy and polarization measurements. The optics is designed for a large energy acceptance to minimize losses in the low energy tail of the disrupted beam. The extraction optics, diagnostic instrumentation and particle tracking simulations are described.

• P. Tenenbaum, T.O. Raubenheimer
  SLAC, Menlo Park, California
• A. Wolski
  LBNL, Berkeley, California

• D.V. Neuffer
  Fermilab, Batavia, Illinois

• Y.L. Yang, J.H. Liu, L. Liu, B. Sun, J.H. Wang, K. Zheng
  USTC/NSRL, Hefei, Anhui

• S.R. Koscielniak
  TRIUMF, Vancouver
• C. Johnstone
  Fermilab, Batavia, Illinois

A fixed-field alternating-gradient accelerator (FFAG) that employs only linear-field elements ushers in a new regime in accelerator design and dynamics. The linear-field machine has the ability to compact an unprecedented range in momenta within a small component aperture. With a tune variation which results from the natural chromaticity, the beam crosses many strong, uncorrec-table, betatron resonances during acceleration. Further, relativistic particles in this machine exhibit a quasi-parabolic time-of-flight that cannot be addressed with a fixed-frequency rf system. This leads to a new concept of bucketless acceleration within a rotation manifold. With a large energy jump per cell, there is possibly strong synchro-betatron coupling. A few-MeV electron model has been proposed to demonstrate the feasibility of these untested acceleration features and to investigate them at length under a wide range of operating conditions. This paper presents a lattice optimized for a 1.3 GHz rf, initial technology choices for the machine, and describes the range of experiments needed to characterize beam dynamics along with proposed instrumentation.

• A. Tatum, J.R. Beene
  ORNL, Oak Ridge, Tennessee

The Holifield Radioactive Ion Beam Facility (HRIBF) is a national user facility dedicated to nuclear structure, reactions, and nuclear astrophysics research with radioactive ion beams (RIBs) using the isotope separator on-line (ISOL) technique. An integrated strategic plan for physics, experimental systems, and RIB production facilities have been developed and implementation of the plan is under way. Specific research objectives are defined for studying the nature of nucleonic matter, the origin of elements, solar physics, and synthesis of heavy elements. Experimental systems upgrade plans include new detector arrays and beam lines, and expansion and upgrade of existing devices. A multifaceted facility expansion plan includes a $4.75M High Power Target Laboratory (HPTL), presently under construction, to provide a facility for testing new target materials, target geometries, ion sources, and beam preparation techniques. Additional planned upgrades include a second RIB production system (IRIS2), an external axial injection system for the present driver cyclotron, ORIC, and an additional driver accelerator for producing high-intensity neutron-rich beams.

• Y. Yano
  RIKEN/RARF/CC, Saitama

• 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

• 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

• 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

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.

• 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

• 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

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.

• J. Wei
  BNL, Upton, Long Island, New York

(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).

• R.M. Zwaska, S.E. Kopp
  The University of Texas at Austin, Austin, Texas
• W. Pellico
  Fermilab, Batavia, Illinois

• A. Miyamoto, H. Hama, F. Hinode, M. Kawai, K. Shinto, T. Tanaka
  LNS, Sendai

• 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

• 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

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.

• M.L. Mallory, J.B. Ball, D. Dowling, E. D. H. Hudson, R. S. L. Lord, A. Tatum
  ORNL, Oak Ridge, Tennessee

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.

• J.-H. Jang, Y.-S. Cho, Y.-H. Kim, H.-J. Kwon
  KAERI, Daejon

A MEBT system of the PEFP(Proton Engineering Frontier Project) has to be installed after the 20MeV DTL where the beam will be supplied to the user group through a beam extraction system. Until now we don't have a plan to put in some matching devices between the RFQ and 20MeV DTL except using the four quadrupole magnets in the first DTL tank as transverse matching tools. The MEBT plays the key role to match the 20MeV output beam into the next accelerator in the longitudinal direction as well as transverse one. This report shows the basic concept and the design status of the system.

• M.L. Lopes, M.N. Martins, P.B. Rios, J. Takahashi
  USP/LAL, Bairro Butantan

In this work we present a new design for the IFUSP main microtron accelerator. The new configuration improves the maximum output energy and eases the operation of the machine. The accelerator will be able to deliver 38 MeV after 43 turns. The input energy was reduced from 4.9 to 2.5 MeV, so that the first microtron stage, the booster, could be eliminated, reducing the number of synchronous stages and easing the operation. We present results for the energy, energy gain and phase slip per turn, and the beam ellipses. We also discuss the design of the insertion and extraction lines.

• E. Mustafin, J. Kaugerts, G. Moritz, G. Walter
  GSI, Darmstadt
• L.N. Latysheva, N. Sobolevskiy
  RAS/INR, Moscow

Radiation damage to various elements of the cosine-theta type dipoles of the SIS300 synchrotron of the FAIR Project was calculated. Among the elements under consideration were the superconducting cable, insulating materials, and high-current by-pass protection diodes. The Monte-Carlo particle transport codes MARS and SHIELD were used to simulate propagation of the lost ions and protons, together with the products of nuclear interactions in the material of the elements. It was found that the lifetime of the protection diodes under irradiation is a more restrictive limit for the tolerable level of beam losses than the occurrence of magnet quenches.

• E.H.R. Gaxiola, J. Bertin, F. Caspers, L. Ducimetière, T. Kroyer
  CERN, Geneva

• E.H.R. Gaxiola, G. Arduini, W. Höfle, F. Roncarolo, E. Vogel, E. Vossenberg
  CERN, Geneva

• S.R. Reeves, C.C. Jensen
  Fermilab, Batavia, Illinois

The temperature stability of the kicker magnet termination resistor assembly directly affects the field flatness and amplitude stability of the kick. Comprehensive thermal enhancements were made to the existing Main Injector resistor assembly design to satisfy NuMI performance specifications. Additionally, a fluid-processing system utilizing Fluorinert® FC-77 high-voltage dielectric was built to precisely control the setpoint temperature of the resistor assembly from 70 to 120F, required to maintain constant resistance during changing operational modes. The Fluorinert® must be continually processed to remove hazardous breakdown products caused by radiation exposure to prevent chemical attack of system components. Design details of the termination resistor assembly and Fluorinert® processing system are described. Early performance results will be presented.

• K.A. Brown, S. Binello, M. Harvey, J. Morris, A. Rusek, N. Tsoupas
  BNL, Upton, Long Island, New York

The NASA Space Radiation Laboratory (NSRL) was constructed in collaboration with NASA for the purpose of performing radiation effect studies for the NASA space program. The NSRL makes use of heavy ions in the range of 0.05 to 3 GeV/n slow extracted from BNL's AGS Booster. NASA is interested in reproducing the energy spectrum from a solar flare in the space environment for a single ion species. To do this we have built and tested a set of software tools which allow the state of the Booster and the NSRL beam line to be changed automatically. In this report we will desribe the system and present results of beam tests.

• R. H. Carcagno, SF. Feher, M.J. Lamm, A. Makulski, R. Nehring, D.F. Orris, Y.M.P. Pischalnikov, M. Tartaglia
  Fermilab, Batavia, Illinois

• S. Peng
  ORNL, Oak Ridge, Tennessee
• L.T. Hoff, K. Smith
  BNL, Upton, Long Island, New York

The low-level RF control system for the SNS Ring differs considerably from that for the Linac. To accommodate requirements for higher data throughput and improved performance the system is based on a PCI Digital Signal Processor (DSP). In accordance with SNS standards, a VME-based PowerPC© is used, but advantage is taken of the on-board PMC slot which houses a Bittware© Hammerhead© PMC card with four AD-21162 DSPs.The EPICS system handles system configuration and data traffic while the DSP performs the low-level RF controls. Protocol and software to support both the PowerPC and the DSP have been developed. This paper presents the system design and initial testing experience.

• S.M. Hartman, S. Mikhailov, Y.K. Wu
  DU/FEL, Durham, North Carolina

The Duke FEL is developing a booster synchrotron to provide full energy injection into the Duke electron storage ring. In this paper, we describe the development of the control system for the booster. Requirements include the competing needs of simple and reliable turn-key operation for the machine as a booster; and the sophistication and flexibility of operation of the machine as a storage ring for commissioning, machine studies and as a light source. To simplify operations and machine studies, the high level controls will present the system in terms of the physics quantities of the accelerator, allowing a tight integration between the physics model and the low level hardware control, as we have previously implemented for Duke storage ring.