• M.H. Lieng
  UNIDO, Dortmund
• R. Appleby, G. Corti
  CERN, Geneva
• V. Talanov
  IHEP Protvino, Protvino, Moscow Region

We consider the formation of machine background induced by proton losses in the long straight section of the LHCb experiment at LHC. Both sources showering from the tertiary collimators located in the LHCb insertion region as well as local beam-gas interaction are taken into account. We present the procedure for, and results of, numerical studies of such background for various conditions. The expected impact on the experiment and signal characteristics are also discussed.

• B.J. Holzer, S.D. Fartoukh, F. Schmidt
  CERN, Geneva

The layout of the interaction region for the LHC upgrade project is based on a number of new magnets that will provide the required strengths to focus the colliding beams as well as to separate them after the collision. As in the nominal LHC, a triplet of quadrupole magnets is foreseen for the upgrade optics and in addition a separator dipole to limit the parasitic bunch crossings of the two counter rotating bunch trains. Due to the smaller beta function at the IP however, the requirements for the free aperture of these IR magnets are more demanding and the effect of the higher order multipoles is more severe than under the nominal LHC conditions. Using the tracking simulations to study these effects, target values for the multipole coefficients of the new magnets have been defined as well as a multipole correction scheme that will be used to compensate those field errors which cannot be avoided due to design and construction tolerances. Based on these considerations the required field quality of the new LHC low beta magnets is discussed and the resulting dynamic aperture for different multipole correction scheme is presented.

• K. Fuchsberger, R. Alemany-Fernandez, G. Arduini, R.W. Assmann, R. Bailey, O.S. Brüning, B. Goddard, V. Kain, M. Lamont, A. Macpherson, M. Meddahi, G. Papotti, M. Pojer, L. Ponce, S. Redaelli, M. Solfaroli Camillocci, W. Venturini Delsolaro, J. Wenninger
  CERN, Geneva

After the incident on the 19th September 2008 and more than one year without beam the commissioning of the LHC started again on November 20, 2009. Progress was rapid and collisions under stable beam conditions were established at 1.2 TeV within 3 weeks. In 2010 after qualification of the new quench protection system the way to 3.5 TeV was open and collisions were delivered at this energy after a month of additional commissioning. This paper describes the experiences and issues encountered during these first periods of commissioning with beam.

• K. Foraz, J. Coupard, S. Grillot
  CERN, Geneva

The first LHC shut-down started in fall 2008, just after the incident on the 19th of September 2008. In addition to the typical work of a shut-down, a large number of interventions, related to the 'consolidation after the incident' were performed in the LHC loop. Moreover the amount of work increased during the shut-down, following the recommendations and conclusions of the different working groups in charge of the safety of the personnel and of the machine. This paper will give an overview of the work performed, the organization of the coordination, emphasizing the new safety risks (electrical and cryogenic), and how the interventions were implemented in order to ensure both the safety of personnel and a minimized time window.

• K. Fuchsberger, S.D. Fartoukh, B. Goddard, V. Kain, M. Meddahi, F. Schmidt, J. Wenninger
  CERN, Geneva

The transfer lines from the SPS to the LHC, TI2 and TI8, with a total length of almost 6km are the longest ones in the world. For that reason even small systematic optics errors are not negligible because they add up and result in an injection mismatch in the LHC. Next to other lattice measurement methods Kick-response measurements were the most important sources of information during the early phases of beam commissioning of these transfer lines and the LHC ring. This measurement technique was used to verify orbit-corrector and BPM gains as well as to sort out optics errors. Furthermore fits to off-momentum kick response turned out to be an appropriate method to establish a model for systematic errors of the transfer line magnets. This paper shortly describes the tools and methods developed for the analysis of the taken data and presents the most important results of the analysis.

• K. Fuchsberger, V. Baggiolini, R. Gorbonosov, W. Herr, V. Kain, G.J. Müller, S. Redaelli, F. Schmidt, J. Wenninger
  CERN, Geneva

MADX (Methodical Accelerator Design) is the de-facto standard software for modeling accelerator lattices at CERN. This feature-rich software package is implemented and maintained in the programming languages C and FORTRAN. Nevertheless the controls environment of modern accelerators at CERN, e.g. of the LHC, is dominated by JAVA applications. A lot of these applications, for example for lattice measurement and fitting, require a close interaction with the numerical models, which are all defined by the use of the proprietary MADX scripting language. To close this gap an API to MADX for the JAVA programming language (JMAD) was developed. Already the current implementation provides access to a large subset of the MADX capabilities (e.g. twiss-calculations, matching or querying and setting arbitrary model parameters) without any necessity to define the models in yet another environment. This paper describes shortly the design of this project as well as the current status and some usage examples.

• K. Fuchsberger, R. Alemany-Fernandez, G. Arduini, R.W. Assmann, R. Bailey, O.S. Brüning, B. Goddard, V. Kain, M. Lamont, A. Macpherson, M. Meddahi, G. Papotti, M. Pojer, L. Ponce, S. Redaelli, M. Solfaroli Camillocci, W. Venturini Delsolaro, J. Wenninger
  CERN, Geneva

Following the LHC injection tests of 2008, two injection tests took place in October and November 2009 as preparation for the LHC restart on November 20, 2009. During these injection tests beam was injected through the TI2 transfer line into sector 23 of ring 1 and through TI8 into the sectors 78, 67 and 56 of ring 2. The beam time was dedicated to injection steering, optics measurements and debugging of all the systems involved. Because many potential problems were sorted out in advance, these tests contributed to the rapid progress after the restart. This paper describes the experiences and issues encountered during these tests as well as related measurement results.

• R. Bartoldus, I. Aracena, P. Grenier, D.W. Miller, E. Strauss, D. Su
  SLAC, Menlo Park, California
• J. Beringer, P. Loscutoff
  LBNL, Berkeley, California
• H. Burkhardt, S.M. White
  CERN, Geneva
• W. Kozanecki
  CEA, Gif-sur-Yvette
• J. Walder
  Lancaster University, Lancaster

We present results from the measurement of the 3-D luminosity distribution with the ATLAS Inner Detector during early running. The spatial distribution of pp interactions is reconstructed by a dedicated algorithm in the High-Level Trigger that fits tracks and primary event vertices in real time, and by an offline algorithm that takes full advantage of the high tracking efficiency and resolution. The number of vertices provides online monitoring of the instantaneous luminosity, while luminous-centroid motion mirrors IP-orbit and RF-phase drifts. The x, y and z luminous widths reflect the evolution of the transverse and longitudinal emittances. The length scales of the IP orbit bumps, which directly impact the accuracy of the transverse convolved beam sizes measured during van der Meer scans, are calibrated offline against the measured displacement of the luminous centroid; this significantly improves the accuracy of the absolute luminosity calibration. The simultaneous determination, during such scans, of the transverse convolved beam sizes (from the luminosity variation) and of the corresponding luminous sizes can be used to disentangle the transverse IP sizes of the two beams.

• M. Meddahi, S. Bart Pedersen, A. Boccardi, A.C. Butterworth, B. Goddard, G.H. Hemelsoet, W. Höfle, D. Jacquet, M. Jaussi, V. Kain, T. Lefèvre, E.N. Shaposhnikova, J.A. Uythoven, D. Valuch
  CERN, Geneva
• A.S. Fisher
  SLAC, Menlo Park, California
• E. Gianfelice-Wendt
  Fermilab, Batavia

Unbunched beam is a potentially serious issue in the LHC as it may quench the superconducting magnets during a beam abort. Unbunched particles, either not captured by the RF system at injection or leaking out of the RF bucket, will be removed by using the existing damper kickers to excite resonantly the particles in the abort gap. Following beam simulations, a strategy for cleaning the abort gap at different energies was proposed. The plans for the commissioning of the beam abort gap cleaning are described, and the first results from the beam commissioning are presented.

• S. Redaelli, M.C. Alabau Pons, M. Giovannozzi, G.J. Müller, F. Schmidt, R. Tomás, J. Wenninger
  CERN, Geneva

The mechanical aperture of the Large Hadron Collider (LHC) is a critical parameter for the operation of the machine due to the high stored beam intensities in the superconducting environment. Betatron and momentum apertures must be therefore precisely measured and optimized. In this paper, we present the results of beam-based measurements of the LHC aperture. The experimental results are compared with the expectations from the as-built model of the LHC aperture, taking into account the optics imperfections of the superconducting magnets. The impact of these measurements on various aspects of the LHC operation are also discussed.

• S. Redaelli, M.C. Alabau Pons, K. Fuchsberger, M. Giovannozzi, M. Lamont, G.J. Müller, F. Schmidt
  CERN, Geneva
• X. Buffat
  EPFL, Lausanne

The control of the high intensity beams of the CERN Large Hadron Collider (LHC) is particular challenging and requires a precise knowledge of the critical beam and machine parameters. In recent years efforts were devoted to the design of a software infrastructure aimed at mimicking the behavior of the LHC. An online model of the machine, based on the accelerator design tool MADX, has been developed to support the commissioning and the operation of the LHC. This model is integrated into the JAVA-based LHC software framework and provides the full computing power of MADX, including the best knowledge of the machine aperture and magnetic models. The MADX implementation is server-based and provides various facilities for optics computation to other application clients. In this paper, we present the status of the MADX online application and illustrate how it has been used during the LHC commissioning. Possible future implementations are also discussed.

• K.A. Drees
  BNL, Upton, Long Island, New York
• S.M. White
  CERN, Geneva

Using the vernier scan or Van der Meer scan technique, where one beam is swept stepwise across the other while measuring the collision rate as a function of beam displacement, the transverse beam profiles, the luminosity and the effective cross section of the detector in question can be measured. This report briefly recalls the vernier scan method and presents results from the first RHIC polarized proton run at 250 GeV/beam in 2009.

• S.M. White, R. Alemany-Fernandez, H. Burkhardt, M. Lamont
  CERN, Geneva

Once circulating beams have been established in the LHC the first step towards collisions is to remove the physical separation used to avoid collisions during injection and ramp. A residual separation can remain after the collapsing of the separation bumps. The so-called Van Der Meer method allows for a minimization of this unwanted separation by transversally scanning one beam through the other. The beam sizes at the IP can also be determined by this method and used to give an absolute measurement of the luminosity. We report on how this measurement was implemented and performed in the LHC to optimize and calibrate luminosity.

• F. Zimmermann, M. Giovannozzi, S. Redaelli, Y. Sun, R. Tomás, W. Venturini Delsolaro
  CERN, Geneva
• R. Calaga
  BNL, Upton, Long Island, New York

During the 2009 LHC injection tests, the polarities and effects of specific quadrupole and higher-order magnetic circuits were investigated. A set of magnet circuits had been selected for detailed investigation based on a number of criteria. On or off-momentum difference trajectories launched via appropriate orbit correctors for varying strength settings of the magnet circuits under study - e.g. main, trim and skew quadrupoles; sextupole families and spool piece correctors; skew sextupoles, octupoles - were compared with predictions from various optics models. These comparisons allowed confirming or updating the relative polarity conventions used in the optics model and the accelerator control system, as well as verifying the correct powering and assignment of magnet families. Results from measurements in several LHC sectors are presented.

• F. Zimmermann, M. Giovannozzi
  CERN, Geneva
• A. Xagkoni
  National Technical University of Athens, Athens

We study the interaction of macro-particles residing inside the LHC vacuum chamber, e.g. soot or thermal-insulation fragments, with the circulating LHC proton beam. The coupled equations governing the motion and charging rate of metallic or dielectric micron-size macro-particles are solved numerically to determine the time spent by such "dust" particles close to the path of the beam as well as the resulting proton-beam losses, which could lead to a quench of superconducting magnets and, thereby, to a premature beam abort.

• T. Sen
  Fermilab, Batavia

Synchro-betatron resonances can lead to emittance growth and the loss of luminosity. We consider the detailed dynamics of a bunch near such a low order resonance driven by crossing angles at the collision points. We characterize the nature of diffusion and find that it is anomalous and sub-diffusive. This affects both the shape of the beam distribution and the time scales for growth. Predictions of a simplified anomalous diffusion model are compared with direct simulations.

• J. Stiller
  Heidelberg University, Heidelberg
• H.S. Matis, A. Ratti, W.C. Turner
  LBNL, Berkeley, California
• R. Miyamoto
  BNL, Upton, Long Island, New York
• S.M. White
  CERN, Geneva

The LHC BRAN luminosity detector monitors the high luminosity interaction regions (Atlas and CMS). This chamber, which is an Argon gas ionization detector measures the forward neutral particles from collisions the interaction region. To predict and improve the understanding of the detector's performance, we produced a detailed model of the detector and its surroundings in FLUKA. In this paper, we present the model and results of our simulations including the detector's estimated response to interactions for beam energies of 3.5, 5.0, and 7.0 TeV.

• A. Ratti, H.S. Matis, W.C. Turner
  LBNL, Berkeley, California
• E. Bravin, S.M. White
  CERN, Geneva
• R. Miyamoto
  BNL, Upton, Long Island, New York

The Luminosity Monitor for the LHC is ready for operation during the planned 2009-2010 run. The device designed for the high luminosity regions is a gas ionization chamber, that is designed with the ability to resolve bunch by bunch luminosity as well as survive extreme levels of radiation. The devices are installed at the zero degree collision angle in the TAN absorbers ±140m from the IP and monitor showers produced by high energy neutrons from the IP. They are used in real time as a collider operations tool for optimizing the luminosity at ATLAS and CMS. A photo-multiplier based system is used at low luminosities and also available. We will present early test results, noise and background studies and correlation between the gas ionization and the PMT. Comparison with ongoing modeling efforts will be included.

• Z. Li, T.W. Markiewicz, C.-K. Ng, L. Xiao
  SLAC, Menlo Park, California

Crab cavities are proposed for the LHC upgrade to improve the luminosity. There are two possible crab cavity installations for the LHC upgrade: the global scheme at Interaction Region (IR) 4 where the beam-beam separation is about 420-mm, and the local scheme at the IR5 where the beam-beam separation is only 194-mm. One of the design requirements as the result of a recent LHC-Crab cavity workshop is to develop a 400-MHz cavity design that can be utilized for either the global or local schemes at IR4 or IR5. Such a design would offer more flexibility for the final upgrade installation, as the final crabbing scheme is yet to be determined, and save R&D cost. The cavity size of such a design, however, is limited by the beam-beam separation at IR5 which can only accommodate a cavity with a horizontal size of about 145-mm, which is a design challenge for a 400-MHz cavity. To meet the new design requirements, we have developed a compact 400-MHz half-wave spoke resonator (HWSR) crab cavity that can fit into the tight spaces available at either IR4 or IR5. In this paper, we present the optimization of the HWSR cavity shape and the design of HOM, LOM, and SOM couplers for wakefield damping.

• K.A. Brown, L. Ahrens, M. Bai, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, D. Bruno, C. Carlson, R. Connolly, T. D'Ottavio, R. De Maria, K.A. Drees, W. Fischer, W. Fu, C.J. Gardner, D.M. Gassner, J.W. Glenn, Y. Hao, M. Harvey, T. Hayes, L.T. Hoff, H. Huang, J.S. Laster, R.C. Lee, V. Litvinenko, Y. Luo, W.W. MacKay, M. Mapes, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, S. Nemesure, B. Oerter, F.C. Pilat, V. Ptitsyn, G. Robert-Demolaize, T. Roser, T. Russo, P. Sampson, J. Sandberg, T. Satogata, V. Schoefer, C. Schultheiss, F. Severino, K. Smith, D. Steski, S. Tepikian, C. Theisen, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, G. Wang, M. Wilinski, A. Zaltsman, K. Zeno, S.Y. Zhang
  BNL, Upton, Long Island, New York

Since the last successful RHIC Au+Au run in 2007 (Run7), the RHIC experiments have made numerous detector improvements and upgrades. In order to benefit from the enhanced detector capabilities and to increase the yield of rare events in the acquired heavy ion data a significant increase in luminosity is essential. In Run7 RHIC achieved an average store luminosity of <L>=12x10²⁶ cm^-2 s^-1 by operating with 103 bunches (out of 110 possible), and by squeezing to β*=0.8 m. Our goal for this year's run, Run10, was to achieve an average of <L>=27x10²⁶ cm^-2 s^-1. The measures taken were decreasing β* to 0.6 m, and reducing longitudinal and transverse emittances by means of bunched-beam stochastic cooling. In addition we introduced a lattice to suppress intra-beam scattering (IBS) in both RHIC rings, upgraded the RF system, and separated transition crossings in both rings while ramping. We present an overview of the changes and the results in terms of Run10 increased instantaneous luminosity, luminosity lifetime, and integrated luminosity.

• R. Calaga, W. Fischer, G. Robert-Demolaize
  BNL, Upton, Long Island, New York

Long range beam-beam experiments were conducted during the Run 2009 in the yellow and the blue beams of the RHIC accelerator with DC wires. The effects of a long-range interaction with a DC wire on colliding and non-colliding bunches with the aid of orbits, tunes, and losses were studied. Results from distance and currents scans and an attempt to compensate a long-range interaction with a DC wire is presented.

• W. Fischer, E.N. Beebe, D. Bruno, D.M. Gassner, X. Gu, R.C. Gupta, J. Hock, A.K. Jain, R.F. Lambiase, Y. Luo, M. Mapes, W. Meng, C. Montag, B. Oerter, M. Okamura, A.I. Pikin, D. Raparia, Y. Tan, R. Than, J.E. Tuozzolo, W. Zhang
  BNL, Upton, Long Island, New York

In polarized proton operation the luminosity of RHIC is limited by the head-on beam-beam effect, and methods that mitigate the effect will result in higher peak and average luminosities. Two electron lenses, one for each ring, are being constructed to partially compensate the head-on beam-beam effect in the two rings. An electron lens consists of a low energy electron beam that creates the same amplitude dependent transverse kick as the proton beam. We discuss design consideration, present the main parameters, and estimate the performance gains.

• P. Thieberger, R. Bonati, G.F. Corbin, J.P. Cozzolino, A.K. Jain, G.T. McIntyre, M.G. Minty, C. Montag, J.F. Muratore, C. Schultheiss, S. Seberg, J.E. Tuozzolo
  BNL, Upton, Long Island, New York

We report on recent developments for mitigating vibrations of the quadrupole magnets near the interaction regions of the Relativistic Heavy Ion Collider (RHIC). High precision accelerometers, geophones, and a laser vibrometer were installed around one of the two interaction points to characterize the frequencies of the mechanical motion. In addition actuators were mounted directly on the quadrupole cryostats. Using as input the locally measured motion, dynamic damping of the mechanical vibrations has been demonstrated. In this report we present these measurements and measurements of the beam response. Future options for compensating the vibrations are discussed.

• M.G. Minty, R.L. Hulsart, A. Marusic, R.J. Michnoff, V. Ptitsyn, G. Robert-Demolaize, T. Satogata
  BNL, Upton, Long Island, New York

For improved reproducibility of good operating conditions and ramp commissioning efficiency, new dual-plane slow orbit feedback during the energy ramp was implemented during run-10 in the Relativistic Heavy Ion Collider (RHIC). The orbit feedback is based on steering the measured orbit, after subtraction of the dispersive component, to either a design orbit or to a previously saved reference orbit. Using multiple correctors and beam position monitors, an SVD-based algorithm is used for determination of the applied corrections. The online model is used as a basis for matrix computations. In this report we describe the feedback design, review the changes made to realize its implementation, and assess system performance.

• M.G. Minty, A.J. Curcio, W.C. Dawson, C. Degen, Y. Luo, G.J. Marr, B. Martin, A. Marusic, K. Mernick, P. Oddo, T. Russo, V. Schoefer, R. Schroeder, C. Schultheiss, M. Wilinski
  BNL, Upton, Long Island, New York

Precision measurement and control of the betatron tunes and betatron coupling in the Relativistic Heavy Ion Collider (RHIC) are required for establishing and maintaining both good operating conditions and, particularly during the ramp to high beam energies, high proton beam polarization. While the proof-of-principle for simultaneous tune and coupling feedback was successfully demonstrated earlier, routine application of these systems has only become possible recently. Following numerous modifications for improved measurement resolution and feedback control, the time required to establish full-energy beams with the betatron tunes and coupling regulated by feedback was reduced from several weeks to a few hours. A summary of these improvements, select measurements benefitting from the improved resolution and a review of system performance are the subject of this report.

• A. Marusic, M.G. Minty, S. Tepikian
  BNL, Upton, Long Island, New York

Chromaticity feedback during the ramp to high beam energies has been demonstrated in the Relativistic Heavy Ion Collider (RHIC). In this report we review the feedback design and measurement technique. Commissioning experiences including interaction with existing tune and coupling feedback are presented together with supporting experimental data.

• M.G. Minty
  BNL, Upton, Long Island, New York

In this report we present recent experimental data from the Relativistic Heavy ion Collider (RHIC) illustrating effects resulting from of ~ 10 Hz vibrations of the triplet quadrupole magnets in the interactions regions and evaluate the impact of these vibrations on RHIC collider performance. Measurements revealed modulation of the betatron tunes of appreciable magnitude relative to the beam-beam parameter. Comparison of the discrete frequencies in the spectra of the measured beam positions and betatron tunes confirmed a common source. The tune modulations were shown to result from feed-down in the sextupole magnets in the interaction regions. In addition we show that the distortions to the closed orbit of the two counter-rotating beams produced a modulated crossing angle at the interaction point(s).

• C. Montag, L. Ahrens, M. Bai, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, A.V. Fedotov, W. Fischer, G. Ganetis, C.J. Gardner, J.W. Glenn, H. Hahn, M. Harvey, T. Hayes, H. Huang, P.F. Ingrassia, J.P. Jamilkowski, A. Kayran, J. Kewisch, R.C. Lee, D.I. Lowenstein, A.U. Luccio, Y. Luo, W.W. MacKay, Y. Makdisi, N. Malitsky, G.J. Marr, A. Marusic, M.P. Menga, R.J. Michnoff, M.G. Minty, J. Morris, B. Oerter, F.C. Pilat, P.H. Pile, E. Pozdeyev, V. Ptitsyn, G. Robert-Demolaize, T. Roser, T. Russo, T. Satogata, V. Schoefer, C. Schultheiss, F. Severino, M. Sivertz, K. Smith, S. Tepikian, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang
  BNL, Upton, Long Island, New York

During the second half of Run-9, the Relativistic Heavy Ion Collider (RHIC) provided polarized proton collisions at two interaction points with both longitudinal and vertical spin direction. Despite an increase in the peak luminosity by up to 40%, the average store luminosity did not increase compared to previous runs. We discuss the luminosity limitations and polarization performance during Run-9.

• C. Montag, M. Blaskiewicz, J.M. Brennan, S. Tepikian
  BNL, Upton, Long Island, New York

During the acceleration process, heavy ion beams in RHIC cross the transition energy. When RHIC was colliding deuterons and gold ions during Run-8, lattices with different integer tunes were used for the two rings. This resulted in the two rings crossing transition at different times, which proved beneficial for the "Yellow" ring, the RF system of which is slaved to the "Blue" ring. For the symmetric gold-gold run in FY2010, lattices with different transition energies but equal tunes were implemented. We report the optics design concept as well as operational experience with this configuration.

• C. Montag, W. Fischer, D.M. Gassner, P. Thieberger
  BNL, Upton, Long Island, New York
• E. Haug
  University of Tuebingen, Tuebingen

Installation of electron lenses for the purpose of head-on beam-beam compensation is foreseen at RHIC. To optimize the relative alignment of the electron lens beam with the circulating proton (or ion) beam, photon detectors will be installed to measure the bremsstrahlung generated by momentum transfer from protons to electrons. We present the detector layout and simulations of the bremsstrahlung signal as function of beam offset and crossing angle.

• R. De Maria, R. Calaga
  BNL, Upton, Long Island, New York
• M. Giovannozzi, Y. Sun, R. Tomás, F. Zimmermann
  CERN, Geneva

IR4 is a potential candidate for the installation of crab cavities in the CERN Large Hadron Collider. In this paper we present several operational scenarios in which the effect of the kick imparted by the cavity is enhanced by performing a dynamic unsqueeze of the beta function at collision energy. Linear optics, power supply requirements, beam aperture and finally potential luminosity increase studies will be discussed in order to rank and assess the feasibility of the various options.

• T. Fujinaka, T. Matsunaga, S. Mochizuki, H. Takase
  Kyushu University, Center for Accelerator and Beam Applied Science, Fukuoka
• H. Arima, T. Hasuo, N. Ikeda, K. Ishibashi, T. Korenaga, K. Maehata, N. Shigyo, Y. Uozumi, G. Wakabayashi, Y. Yonemura
  Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka
• K. Fujita, T. Morikawa, T. Noro, T. Wakasa
  Kyushu University, Fukuoka
• Y. Mori
  KURRI, Osaka
• H. Nakayama, A. Takagi
  KEK, Ibaraki
• T. Tomimasu
  SAGA, Tosu

150 MeV FFAG accelerator is under construction at Center for Accelerator and Beam Applied Science on Ito Campus to promote activities in all related scientific, medical, engineering and educational field at Kyushu University. In this paper, status of the development of hardware and the results of the beam commissioning of the injector are described.

• M. Fukuda, K. Hatanaka, H. Kawamata, M. Kibayashi, T. Saito, H. Tamura, T. Yorita
  RCNP, Osaka

An upgrade program of the RCNP cyclotron facility for increase of beam intensity and improvement of beam quality is in progress to meet requirements from research in nuclear physics and industrial applications using secondarily produced particles such as neutrons, muons and radioisotopes. A 2.45 GHz ECR ion source using a set of permanent magnets was developed for high intensity proton beam production. The proton beam intensity more than 0.5 mA at an extraction energy of 15 keV has been obtained with a proton ratio more than 80 %. The quality of the pre-accelerated beam from the K140 injector AVF cyclotron has been improved by a flat-top(FT) acceleration system to enhance the beam transmission to the K400 ring cyclotron. Transversal resonant mode of a dee electrode with a span angle of 180 degrees was investigated to achieve the FT acceleration in the frequency region from 50 to 60 MHz. In this paper, developments for high intensity proton beam acceleration and beam quality improvement using the FT acceleration system of the AVF cyclotron will be mainly presented.

• N.Yu. Kazarinov, V.I. Kazacha
  JINR, Dubna, Moscow Region

In order to decrease the energy of an ion accelerated in a cyclotron on value of some MeV/eau it is possible to run an ion beam through a thin metal foil (degrader). One can calculate the final ion energy, angular and energy stragglings, which the beam attains in the degrader, for example, by means of code LISE++. The formulae for calculation of the beam second order moments after degrader were obtained. The formulae for calculation of final beam momentum spread, new values of rms beam emittances, Twiss parameters and the dispersion functions were also obtained. The new ion beam parameters allow one to calculate the beam transportation along the beam line after degrader.

• A. Garonna
  EPFL, Lausanne
• A. Garonna
  TERA, Novara

Hadrontherapy, the technique of tumor radiotherapy employing heavy ion beams, is developing rapidly(*). The TERA Foundation proposes an innovative dedicated accelerator, called Cyclinac(**). It is composed of a 230 MeV/u cyclotron providing fast pulsed beams of H²⁺, for proton therapy with standard techniques, or C⁶⁺, injected into a high gradient linac. Its energy can thus be modulated from pulse to pulse (up to 400 MeV/u), for optimal irradiation of solid tumors with the most modern techniques of dose active spreading. A preliminary design of a superconducting synchrocyclotron for this application is presented. Its advantages are the reduced construction and operating costs (small magnet and low RF power consumption), and the good adaptation of its beam characteristics to therapy (low current and fast repetition rate). The magnet features a central field of 5 T, which has azimuthal symmetry and decreases with the radius, ensuring radial and vertical focusing. The weight is around 300 t. Ions are produced in an EBIS, injected axially and resonantly extracted at 1 m radius. The RF is mechanically modulated by a rotating capacitor, providing the required 400 Hz repetition rate.

* U. Amaldi, G. Kraft, J.Rad. Res., 48 Suppl A (2007) 27
** U. Amaldi, S. Braccini, P. Puggioni, Reviews of Accelerator Science and Technology, Vol.2 (2009)

• D.J. Kelliher, S. Machida
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon
• S.L. Sheehy
  JAI, Oxford

A novel nonlinear, nonscaling FFAG ring has been designed for proton and ion acceleration [1]. It can be used for proton and carbon therapy as well as a proton driver for various facilities such as a high intensity neutrino factory. The machine has novel features including variable energy extraction and a high repetition rate of about 1 kHz. Taking as an example the PAMELA proton ring, under study at the John Adams Institute in Oxford, we present results of an error study. A calculation of alignment tolerance is made, in which the effects of translational misalignments of the triplet magnets are included. The effect of misalignments on the dynamic aperture of the machine is investigated.

[1] S. L. Sheehy, K. J. Peach, H. Witte, D. J. Kelliher and S. Machida, Phys. Rev. ST Accel. Beams, 13 (2010) 040101

• S. Machida
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon

The lattice of a Fixed Field Alternating Gradient (FFAG) accelerator normally has high symmetry. The whole ring consists of many identical cells which have a simple FODO, double or triplet focusing unit. There is, however, no real reason for an FFAG lattice to have high symmetry, except for a linear nonscaling design which relies on high symmetry to avoid betatron resonances. We propose an FFAG lattice design with a superperiod that makes it possible to have long straight sections for injection, extraction and rf cavities. We discuss how to introduce a superperiod structure. The impact on dynamic aperture, dispersion function, longitudinal dynamics as well as the advantage of having long straight sections will be presented.

• R.T.P. D'Arcy
  UCL, London
• D.J. Holder, B.D. Muratori
  Cockcroft Institute, Warrington, Cheshire
• J.K. Jones
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire

EMMA (Electron Machine with Many Applications) is a prototype non-scaling Fixed Field Alternating Gradient (NS-FFAG) accelerator presently under construction at Daresbury Laboratory, UK. The energy recovery linac ALICE will serve as an injector for EMMA within the energy range of 10 to 20 MeV. The injection line consists of a symmetric 30° dogleg to extract the beam from ALICE, a matching section and a tomography section for transverse emittance measurements. This is followed by a transport section to the injection point of the EMMA ring. Commissioning of the EMMA injection line started in early 2010. A number of different injection energy and bunch charge regimes are planned; for some of the regimes the effects of space charge will be significant. It is therefore necessary to model the electron beam transport in this line using a code capable of both calculating the effect of, and compensating for, space charge. Therefore the General Particle Tracer (GPT) code has been used. A range of injection beam parameters have been modelled for comparison with experimental results.

• R.J. Barlow, A.M. Toader, S.C. Tygier
  UMAN, Manchester

Accelerator Driven Subcritical Reactors require a high currents of energetic protons. We compute the limits imposed by space charge, and explore what can be achieved using various proposed FFAG lattices. Limitations due to beam losses and reliability are also discussed

• T. Yokoi, K.J. Peach, H. Witte
  JAI, Oxford

PAMELA (Particle Accelerator for MEdicaL Application) aims to design a particle therapy facility using Non-scaling FFAG (Fixed Field Alternating Gradient) accelerator. In the beam extraction in PAMELA, the biggest challenge is the flexible energy variability, which is desirable for better dose field formation. The feature is a unique feature of PAMELA for a fixed field accelerator. To realize energy variable beam extraction, PAMELA employs vertical extraction using large a aperture kicker magnet. In the paper, the detail of the extraction scheme, hardware specifications are discussed.

• T. Adachi, T. Kawakubo
  KEK, Ibaraki
• T. Yoshii
  Nagaoka University of Technology, Nagaoka, Niigata

New acceleration system using an induction cell has been developed at KEK by using KEK 12-GeV PS*. We call an accelerator using the induction acceleration system "Digital Accelerator". The PS-Booster is now being renovated as the first Digital Accelerator (DA) by introducing the induction acceleration instead of rf**. Argon ion beam from the ECR ion source is injected to the DA by an electrostatic beam kicker. Another electrostatic device with the same structure is used for chopping the beam before injection. The accelerated beam is extracted by the existing extraction system, which comprises bump, septum and kicker magnets. Since these magnets are installed in a vacuum chamber, vacuum pressure deteriorates due to outgas from them. In order to reduce a beam loss in the DA ring, the pressure level is crucial especially for an ion beam. Therefore, we decided to put the septum magnet outside the vacuum chamber and insert a vacuum duct in the gap, since it dominantly contributes to the vacuum pressure more than the other magnets. This paper describes the electrostatic beam chopper, injection kicker and septum magnet containing the vacuum duct for the KEK DA and beam dynamics.

*K. Takayama, Phys. Rev. Lett. 98, 054801 (2007)
**K. Takayama, "KEK Digital Accelerator for Material and Biological Sciences", T. Iwashita, "Induction Acceleration System", in this conference

• T. Iwashita, T. Adachi, T. Arai, Y. Arakida, M. Hasimoto, H. Someya, K. Takayama, M. Wake
  KEK, Ibaraki
• T.S. Dixit
  SAMEER, Mumbai
• K. Mochiki, T. Sano
  Tokyo City University, Tokyo

The KEK-DA (Digital Accelerator) is a modification of the KEK 500 MeV booster*, in which an induction acceleration system is employed. It has an ability to accelerate arbitrary ions with their possible charge states**. An outline of the acceleration scenario is described and a necessary control system fully integrating the induction acceleration system is given in details. The KEK-DA is a rapid cycle synchrotron operating at 10 Hz; the accelerating pulse voltage must be dynamically varied in time to follow the ramping magnetic field. A novel technique combining the pulse density control and intermittent operation of acceleration cells is required. The intelligent gate control system which uses 1 GHz digital signal processors (DSPs) has been designed. Construction of the KEK-DA is in the final stage; installation of the induction cells and the power supplies are done. The whole system including gate control system is demonstrated with high voltage outputs,long-term stability of the system through a heat run is examined. Also a future plan which replaces DSPs by FPGA (Field Programmable Gate Array)is discussed.

* K.Takayama et al., JOURNAL OF APPLIED PHYSICS 101, 063304 (2007).
** K.Takayama et al., "KEK Digital Accelerator for Material and Biological Sciences" in this conference.

• K. Takayama, T. Adachi, T. Arai, Y. Arakida, M. Hasimoto, T. Iwashita, E. Kadokura, M. Kawai, T. Kawakubo, K. Koyama, T. Kubo, T. Kubo, H. Nakanishi, K. Okamura, H. Someya, A. Takagi, M. Wake
  KEK, Ibaraki
• T. Kikuchi, T. Yoshii
  Nagaoka University of Technology, Nagaoka, Niigata
• K.W. Leo
  Sokendai, Ibaraki
• K. Mochiki, T. Sano
  Tokyo City University, Tokyo
• M. Okamura
  RBRC, Upton, Long Island, New York
• K. Okazaki
  Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture
• H. Tanaka
  Iwate university, Morioka, Iwate

A novel circular accelerator capable of accelerating any ions from an extremely low energy to relativistic energy is discussed. A digital accelerator (DA)* is based on the induction synchrotron concept, which had been demonstrated in 2006. All ions are captured and accelerated with pulse voltages generated by induction acceleration cell (IAC). The IAC is energized by the switching power supply, in which power solid-state conductors are employed as switching elements and their tuning on/off is maneuvered by gate signals digitally manipulated from the circulating signal of an ion beam. Acceleration synchronized with the revolution of the ion beam is always guaranteed. The concept is realized by renovating the KEK 500 MeV booster into the DA, introducing a laser ablation ion source. Ion energy of 85-140 MeV/au and intensity of 10⁺⁹ - 10⁺¹⁰ /sec are estimated and these ions will be delivered without any large-scale injector. Companion papers** will discuss more details of instruments of DA. Applications for innovative material sciences and life sciences will be briefly introduced as well as the outline of DA.

*K. Takayam, J. of Appl. Phys. 101 (2007) 063304.
**K.Takayama "Ion source and LEBT", T.Adachi "Injection and extraction system", T.Iwashita "Induction acceleration system" in this conference.

• K. Takayama, T. Adachi, T. Arai, Y. Arakida, M. Hasimoto, T. Kawakubo, K. Koyama, T. Kubo, T. Kubo, H. Nakanishi, A. Takagi, K. Zhang
  KEK, Ibaraki
• T. Kikuchi
  Nagaoka University of Technology, Nagaoka, Niigata
• K.W. Leo
  Sokendai, Ibaraki
• K. Okazaki
  Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture

KEK digital accelerator (DA) capable of accelerating all species of ion* is an induction synchrotron employing no large scale injectors. At the beginning of its operation, Ar ions from the ECR ion source (ECRIS) embedded in the 200 kV high voltage terminal (HVT) are directly injected into KEK-DA though the low energy BT line (LEBT). The permanent magnet ECRIS was assembled at KEK. Its characteristics such as a charge-state spectrum, emittance, and intensity are presented. The 200 kV HVT has been also assembled at KEK. Its voltage stability in the pulse mode operation, where a plasma of 1 msec is created by x-band microwaves at 10 Hz, is discussed. The LEBT consists of the Eintzel lens, momentum analyzer, B magnets with edge focusing, electrostatic chopper**, and a combination of Q magnets. In the upper LEBT from the ion extraction hall to the entrance of the analyzer, possible charge-state ions are contaminated in the space-charge limit and beam focusing is realized through the Eintzel lens and tandem acceleration gaps. In the lower LEBT from the analyzer to the KEK-DA injection point, the lattice has been optimized so as to meet optics matching at the injection point.

*K. Takayama, J. of Appl. Phys. 101 063304(2007), "KEK digital accelerator for material and biological sciences" in this conference
**T.Adachi, "Injection and extraction system" in this conference

• N. Grouas, P. Bosland, P. Bredy, G. Disset, P. Hardy, V.M. Hennion, H. Jenhani, J. Migne, A. Mohamed, F. Orsini, J. Plouin, J. Relland
  CEA, Gif-sur-Yvette
• B. Branas Lasala, I. Podadera Aliseda, S. Sanz, F. Toral
  CIEMAT, Madrid
• E.N. Zaplatin
  FZJ, Jülich

The IFMIF project aims to build a high intensity material irradiation facility which one of the main components is a high intensity deuteron accelerator. A prototype of this accelerator will be built in Rokkasho in Japan. It includes a cryomodule composed of 8 superconducting cavities (HWR) powered by 200 kW couplers to accelerate the deuteron beam from 5 MeV to 9 MeV. The beam is focused inside the cryomodule by 8 superconducting solenoids. The cryomodule design has to respect some severe beam dynamics requirements, in particular a restricted space for the component interfaces and an accurate alignment to be kept during cooling down. A double cryogenic system has been designed as it is necessary to control the cavity cooling independently from the solenoid one. The cryomodule design should also be compatible with its environment in the Rokkasho building. This paper gives then a general overview of the 1rst cryomodule current design and its interfaces. It defines the concept chosen for the Cryogenic System, explains the method foreseen for the assembly and alignment and describes the integration study in Rokkasho.

• H. Jenhani, P. Bosland, P. Bredy, M. Desmons, G. Devanz, G. Disset, N. Grouas, P. Hardy, V.M. Hennion, J. Migne, A. Mohamed, F. Orsini, J. Plouin, J. Relland
  CEA, Gif-sur-Yvette
• B. Branas Lasala, I. Podadera Aliseda, S. Sanz, F. Toral
  CIEMAT, Madrid
• F.M. Mirapeix, C. Palacios
  TTI, Santander
• E.N. Zaplatin
  FZJ, Jülich

The driver of the International Fusion Material Irradiation Facility (IFMIF) consists of two 125 mA, 40 MeV CW deuteron accelerators. A superconducting option for the 5 to 40 MeV linac based on Half-Wave Resonators (HWR) has been chosen. The first cryomodule houses 8 HWR's supplied by high power RF couplers; each of them should be able to operate at 200 kW in CW. This paper will give an overview of the RF design of the 175 MHz CW power coupler. The detailled mechanical studies and the realization will be performed by the Industry. Global approach of the contract with the Industry and the organization of the intermediate validation tests will be discussed. In a second part, the choices and the last advances concerning the couplers RF power test stand will be described.

• A. Mosnier, P.-Y. Beauvais, R. Gobin, J.-F. Gournay, P. Joyer, J. Marroncle, P.A.P. Nghiem, F. Orsini
  CEA, Gif-sur-Yvette
• B. Brañas, A. Ibarra, P. Méndez, I. Podadera Aliseda, J. Sanz, F. Toral
  CIEMAT, Madrid
• M. Comunian, A. Facco, A. Palmieri, A. Pepato, A. Pisent
  INFN/LNL, Legnaro (PD)
• P. Garin, Ch. Vermare
  IFMIF/EVEDA, Rokkasho
• R. Heidinger
  Fusion for Energy, Garching
• H. Kimura, T. Kojima, T. Kubo, S. Maebara, S. O'hira, Y. Okumura, K. Shinto, H. Takahashi, K. Yonemoto
  JAEA, Aomori

The objectives of the IFMIF/EVEDA project are to produce the detailed design of the entire IFMIF facility, as well as to build and test a number of prototypes, including a high-intensity CW deuteron accelerator (125 mA @ 9 MeV). Most of the accelerator components (Injector, RFQ, Superconducting RF-Linac, Transport Line and Beam Dump, RF Systems, Local control systems, beam instrumentation) are designed and provided by European institutions (CEA/Saclay, CIEMAT, INFN/LNL, SCK-CEN), while the RFQ couplers, the supervision of the control system and the building including utilities constructed at Rokkasho BA site are provided by JAEA. The coordination between Europe and Japan is ensured by an international project team, located in Rokkasho, where the accelerator will be installed and commissioned. The design and R&D activities are presented, as well as the schedule of the prototype accelerator.

• F. Orsini, P. Bosland, P. Bredy, G. Disset, N. Grouas, P. Hardy, V.M. Hennion, H. Jenhani, J. Migne, A. Mohamed, J. Plouin, J. Relland
  CEA, Gif-sur-Yvette
• B. Branas Lasala, I. Podadera Aliseda, S. Sanz, F. Toral
  CIEMAT, Madrid
• E.N. Zaplatin
  FZJ, Jülich

In the framework of the International Fusion Materials Irradiation Facility (IFMIF), which consists of two high power CW accelerator drivers, each delivering a 125 mA deuteron beam at 40 MeV, an accelerator prototype is presently under design for the first phase of the project. A superconducting option has been chosen for the 5 MeV RF Linac, based on a cryomodule composed of 8 low-beta Half-Wave Resonators (HWR), 8 Solenoid Packages and 8 RF couplers. This paper will focus on the HWR sub-system: the RF, thermo-mechanical design, and the realization of the first prototype of HWR will be presented. The resonator tuning frequency is controlled by an innovant Cold Tuning System (CTS), located in the central region of the cavity. The different options for tuning will be discussed and the final thermo-mechanical design will be detailed. First validation test results of the CTS are expected for the conference.

• P. Puppel, U. Ratzinger
  IAP, Frankfurt am Main
• L.H.J. Bozyk
  TU Darmstadt, Darmstadt
• P.J. Spiller
  GSI, Darmstadt

StrahlSim is a unique code for the simulation of charge exchange driven beam loss and dynamic vacuum effects in heavy ion synchrotrons. Dynamic vacuum effects are one of the most challenging problems for accelerators using intermediate charge state, high intensity heavy ion beams (e.g. AGS Booster, LEIR, SIS18). StrahlSim can be used as a design tool for synchrotrons, e.g. for the estimation of pumping power needed to stabilize the dynamic vacuum. Recently, StrahlSim has been extended to simulate time dependent longitudinal pressure profiles. The new code calculates a self-consistent static pressure distribution along the accelerator and simulates local pressure rises caused by dynamic and systematic beam losses. StrahlSim determines the loss distribution of charge exchanged beam ions and respects the beam energy dependence of the charge exchange cross sections. The beam loss calculated by means of the new time dependent longitudinal pressure profiles has been benchmarked with measured data from the latest SIS18 machine experiments.

• U. Ratzinger, L.P. Chau, H. Dinter, M. Droba, M. Heilmann, N.S. Joshi, O. Meusel, I. Müller, D. Mäder, Y.C. Nie, D. Noll, H. Podlech, H. Reichau, A. Schempp, S. Schmidt, K. Volk, C. Wagner, C. Wiesner
  IAP, Frankfurt am Main
• R. Reifarth
  IKF, Frankfurt-am-Main

An intense 2 MeV, 200 mA proton beam will drive a neutron source by the reaction Li7(p,n)Be7 on solid as well as on liquid lithium targets. Actually, the facility is under construction at the physics faculty new experimental hall in Frankfurt. To study in detail the burning of elements in stars by the s-process, a pulsed beam operation with a bunch compressor at the linac exit will offer several Ampere beam current within 1 ns pulse length and with 250 kHz rep. rate at the n - production target. As the upper limit of generated neutrons and the total n- flux at this source are well defined the sample for neutron capture measurements can be placed after a time of flight path as short as 0.8 m only. This will provide highest accessible pulsed neutron flux rates for neutron energies in the 1 - 500 keV range. The highly space charge dominated bunch forming process as well as the ion source, the rf coupled 175 MHz RFQ/DTL - resonator and the target development will be explained.

• A. Pepato, R. Dima, F. Scantamburlo
  INFN- Sez. di Padova, Padova
• M. Comunian, E. Fagotti, F. Grespan, A. Palmieri, A. Pisent, C. Roncolato
  INFN/LNL, Legnaro (PD)
• D. Dattola, P. Mereu
  INFN-Torino, Torino

In the framework of the IFMIF/EVEDA project, the RFQ is a 9.8 m long cavity, with very challenging mechanicals specification. In the base line design, the accelerator tank is composed of 18 modules that are flanged together. The construction procedure of each module foresees the horizontal brazing of the four electrodes and then the vertical brazing of the flanges. A RFQ prototype, composed of 2 modules, aimed at testing all the mechanical construction procedure is under construction. In this article, the progress of the prototype construction and the progresses in the design and engineering phase, as well the description of all the fabrication phases is reported.

• A. Palmieri, F. Grespan
  INFN/LNL, Legnaro (PD)
• G. Cotto
  Torino University, ., Torino
• D. Dattola, P. Mereu
  INFN-Torino, Torino

In order to validate the tuning and stabilization procedures established for the IFMIF RFQ, a campaign of low power tests on an aluminum real-scale RFQ built on purpose has been carried out. Such campaign consisted of the determination of mode spectra, the measurements of the electric field distribution with bead pulling technique, and the implementation of the tuning procedure. The main outcomes and results obtained are reported in the article.

• A. Palmieri, F. Grespan, A. Pisent
  INFN/LNL, Legnaro (PD)

An important issue for high intensity RFQs (tenth of mA beam current and more) is the necessity of keeping the beam losses as low as possible, in order to allow reliable and safe maintenance of the machine. Typically, beam dynamics outcomes driven by these constraints result both in a RFQ length that is considerably higher than the wavelength and in an intra-vane voltage admitted variation with respect to the design value that must not exceed a few percent. Therefore an analytical tool is needed in order to foresee the effect of geometric perturbations on the voltage profile, in order to give an indication on the permitted ranges of geometrical errors in the RFQ construction. In this article a five conductors transmission line equivalent circuit for the four-vane RFQ is presented and the effects of geometrical perturbations on the voltage profile are analyzed in some particular cases. The case study is the IFMIF RFQ (125 mA deuteron current, 9.8 m length, 175 MHz frequency), whose features are particularly suitable for this kind of analysis.

• Y. Irie, S. Fukumoto, K. Muto, H. Nakanishi, A. Takagi
  KEK, Ibaraki
• D. Bayley, I.S.K. Gardner, R.J. Mathieson, A. Seville, J.W.G. Thomason
  STFC/RAL/ISIS, Chilton, Didcot, Oxon
• J.C. Dooling, D. Horan, R. Kustom, M.E. Middendorf
  ANL, Argonne
• T. Oki
  Tsukuba University, Ibaraki

A low-output-impedance RF system for the second harmonic cavity in the ISIS synchrotron has been developed by collaboration between Argonne National Laboratory (US), KEK (Japan) and Rutherford Appleton Laboratory (UK). The system has less than 30 Ω of output impedance over wide frequency range of 2.7-6.2 MHz. However, distortions of voltage waveform in the driver stage have been a long-standing issue. It was found such distortions were generated depending upon the higher-order-modes of the anode-choke impedance. In this report, method to realize the smooth sinusoidal waveform in the wideband system is presented.

• M. Yoshioka, H. Kobayashi, H. Matsumoto
  KEK, Ibaraki

The J-PARC accelerator complex consists of a linear accelerator (330 m long, 181 MeV), a rapid cycling synchrotron (3 GeV RCS, 350 m circumference, 25 Hz) and a slow cycling synchrotron (MR, 30 GeV as a first step energy, 1600 m circumference, typically with 3.5 sec cycle). The RCS provides high intensity proton beam to the materials and life science facility and the MR. The MR has two beam extraction lines. One is a slow extraction system for the hadron physics, and other a fast extraction system for neutrino science. We have to challenge many issues to complete construction of the J-PARC accelerator facility on-schedule in 2008 despite all the hardships, such as the problems included in the original design, technology choices and fabrication procedure of the machine components, and construction of conventional facilities. As a first step of operation, we could commission all accelerator facilities and provide beam to all experimental facilities in 2009 successfully. We will report about analysis of these issues and how to solve them, which is a necessary step to realize the design beam power as a next step, and to challenge the future upgrade beyond the original design.

• M. Yoshii, K. Hara, C. Ohmori, T. Shimada, H. Suzuki, M. Tada
  KEK/JAEA, Ibaraki-Ken
• E. Ezura, K. Hasegawa, A. Takagi, K. Takata
  KEK, Ibaraki
• M. Nomura, A. Schnase, F. Tamura, M. Yamamoto
  JAEA/J-PARC, Tokai-mura

The Japan Proton Accelerator Complex includes the 3GeV rapid cycling synchrotron (RCS) and the 50GeV main ring synchrotron (MR). Both synchrotrons use the high field gradient magnetic alloy (MA) loaded cavities. In RCS, 11 RF systems have been fully operational since December 2008. The RCS RF systems are operated with dual-harmonic acceleration voltages. Beam acceleration and bunch shape manipulation are efficiently taking place. 120kW of the neutron user operation was started at the Material and Life science facilities in November 2009. In MR synchrotron, the 5th RF system were installed in August 2009, and therefore 5 RF systems are now in operation. Beam commissioning for delivering protons to the hadron facility and neutrino beam experimental facility are under way. The neutrino user experiment is intended to start January 2010. Proton beam operation with more than 100kW is required. The approaches to realizing high intensity operation and the MR upgrade plan will be presented.

• H. Ao, K. Hirano, T. Morishita
  JAEA/LINAC, Ibaraki-ken
• H. Asano, N. Ouchi, N. Tsubota
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• K. Hasegawa
  JAEA, Ibaraki-ken
• F. Naito, K. Takata
  KEK, Ibaraki
• V.V. Paramonov
  RAS/INR, Moscow
• Y. Yamazaki
  J-PARC, KEK & JAEA, Ibaraki-ken

The mass production of the ACS (Annular Coupled Structure) cavity started from March 2009 for the J-PARC Linac energy upgrade from 181 MeV to 400 MeV. This upgrade project requires 18 ACS accelerating modules and two debunchers additionally within three years. The construction schedule is so tight that we have to optimize the fabrication process. For example the geometrical beta is varied for each accelerating module, thus the several test cells were fabricated and for the all beta before the mass production to confirm the initial design and the frequency tuning procedure. This paper describes our approach for the mass production and the current status and results.

• K. Hasegawa, T. Kobayashi, Y. Kondo, T. Morishita, H. Oguri
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• Y. Hori, C. Kubota, H. Matsumoto, F. Naito, M. Yoshioka
  KEK, Ibaraki

The J-PARC RFQ (length 3.1m, 4-vane type, 324 MHz) accelerates a beam from the ion source to the DTL. The beam test of the linac was started in November 2006 and 181 MeV beam was successfully accelerated in January 2007. Since then, the linac has been delivered beams for commissioning of the linac itself, downstream accelerators and facilities. Trip rates of the RFQ, however, unexpectedly increased in Autumn 2008, and we have been suffering from this issue for user run operation since then. We tried to recover by tender conditioning, modification of RF control, improvement of vacuum properties and so on. By taking these measures, we manage to have 2 to 3 days continuous beam operation. In this report, we describe the status of the RFQ.

• H. Hotchi, H. Harada, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• Y. Irie
  KEK, Ibaraki

We have recently demonstrated 300-kW output in the J-PARC 3-GeV RCS. In this paper we will discuss beam dynamics issues in such a high intensity beam operation together with the corresponding beam simulation results.

• M. Kinsho
  JAEA/J-PARC, Tokai-mura

The J-PARC 3-GeV rapid cycling synchrotron (RCS) has been operated for the neutron and MLF users program from December 23rd, 2008. The RCS operations not only in support of the MLF but also were providing beam to support commissioning of the MR. In parallel we are challenging to realize higher beam power operations with better stability. Before scheduled maintenance last summer beam power was limited by the front end of about 20 kW, after that maintenance the RCS has been operated the beam power of more than 100 kW for MLF users. After beam deliver operation to the MR and MLF, while the priority has been given to their beam tuning, the RCS also continues further beam studies toward higher beam intensity. On December 7th, 2009, the RCS achieved the beam power of more than 300kW to the neutron production target with 25Hz. This presentation will concentrate itself on the outcome of the J-PARC RCS commissioning program, including the discussion on the issues of the high-power operation.

• S. Wang, Q. Qin
  IHEP Beijing, Beijing

The accelerator of China Spallation Neutron Source (CSNS) consists of a low energy linac and a Rapid Cycling Synchrotron (RCS). The opimization of beam dynamics design for RCS and two beam transport line are introduced, and the details design and some simulation results are presented.

• J. Wei, Y.J. Bai, J.C. Cai, H. Chen, C. Cheng, Q. Du, T. Du, Q.X. Feng, Z. Feng, H. Gong, X. Guan, X.X. Han, T.C. Huang, Z.F. Huang, R.K. Li, W.Q. Li, C.-K. Loong, C.-X. Tang, Y. Tian, X.W. Wang, X.F. Xie, Q.Z. Xing, Z.F. Xiong, D. Xu, Y.G. Yang, Z. Zeng, H.Y. Zhang, X.Z. Zhang, S.X. Zheng, Z.H. Zheng, B. Zhong
  TUB, Beijing
• J.H. Billen, L.M. Young
  LANL, Los Alamos, New Mexico
• S. Fu, J. Tao, Y.L. Zhao
  IHEP Beijing, Beijing
• W.Q. Guan, Y. He, G.H. Li, J. Li, D.-S. zhang
  NUCTECH, Beijing
• J.H. Li
  CIAE, Beijing
• T.J. Liang
  Institute of Physics, Chinese Academy of Sciences, Beijing
• Z.W. Liu, L.T. Sun, H.W. Zhao
  IMP, Lanzhou
• B.B. Shao
  Tsinghua University, Beijing
• J. Stovall
  CERN, Geneva

This paper reports the design and construction status, technical challenges, and future perspectives of the proton-linac based Compact Pulsed Hadron Source (CPHS) at the Tsinghua University, Beijing, China.

• Y. Lee, P.-A. Duperrex, V. Gandel, D.C. Kiselev, U. Müller
  PSI, Villigen

A new current monitor (MHC5) based on a re-entrant cavity tuned at the 2nd RF harmonic (101.26 MHz) has been in operation since April 2009 at PSI. It monitors the current of the high intensity 590 MeV proton beam at 8 m downstream of the graphite meson production target (TgE). The scattered particles and their secondaries from TgE introduce a heavy thermal load approximately of 230 W on MHC5 at 2 mA beam intensity, which is carried away by active water cooling. The inhomogeneous temperature profile in MHC5 results in thermomechanical deformations which leads to a change in its HF electromagnetic characteristics. Indeed, an anomalous RF drifts were observed during initial operations, which had to be compensated for, to obtain correct beam current monitoring. In this paper, the physics of the observed RF drift is analyzed by using advanced multiphysics simulation technologies.

• B. Jones, D.J. Adams, S.J.S. Jago, H. V. Smith, C.M. Warsop
  STFC/RAL/ISIS, Chilton, Didcot, Oxon

The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. The accelerator facility consists of a 70 MeV H^- linac and a 50 Hz proton synchrotron accelerating up to 3.75x10¹³ protons per pulse from 70 to 800 MeV, delivering a mean beam power of 0.24 MW. Present upgrade studies are investigating how replacement of the existing linac and increased injection energy could increase beam power in the existing ISIS ring. Such an upgrade would replace one of the oldest sections of the ISIS machine, and with reduced space charge and optimised injection, may allow substantially increased intensity in the ring, perhaps towards the 0.5 MW regime. A critical aspect of such an upgrade would be the new higher energy injection straight. This paper summarises beam dynamics and hardware requirements for 180MeV H^- charge exchange injection into ISIS including; optimisation of the injection magnets; requirements for beam dumps and results of stripping foil simulations with estimates of stripping efficiency and foil heating.

• A.P. Letchford, M.A. Clarke-Gayther, D.C. Faircloth, S.R. Lawrie, M. Perkins, P. Wise
  STFC/RAL/ISIS, Chilton, Didcot, Oxon
• S.M.H. Alsari, S. Jolly, D.A. Lee, P. Savage
  Imperial College of Science and Technology, Department of Physics, London
• I. Ariz, R. Enparantza, P. Romano, A. Sedano
  Fundación TEKNIKER, Eibar (Gipuzkoa)
• J.J. Back
  University of Warwick, Coventry
• F.J. Bermejo
  Bilbao, Faculty of Science and Technology, Bilbao
• M. Eguiraun
  ESS-Bilbao, Zamudio
• V. Etxebarria
  University of the Basque Country, Faculty of Science and Technology, Bilbao
• C. Gabor, D.C. Plostinar
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon
• N. Garmendia, H. Hassanzadegan
  ESS Bilbao, Bilbao
• A. Kurup
  Fermilab, Batavia
• J.K. Pozimski
  STFC/RAL, Chilton, Didcot, Oxon

The Front End Test Stand (FETS) under construction at the Rutherford Appleton Laboratory is the UK's contribution to research into the next generation of High Power Proton Accelerators (HPPAs). HPPAs are an essential part of any future Spallation Neutron Source, Neutrino Factory, Muon Collider, Accelerator Driven Sub-critical System, Waste Transmuter etc. FETS will demonstrate a high quality, high intensity, chopped H-minus beam and is a collaboration between RAL, Imperial College and the Universtity of Warwick in the UK and the Universidad del Pais Vasco in Spain. This paper describes the current status and future plans of FETS.

• S. Jolly, M.J. Easton
  Imperial College of Science and Technology, Department of Physics, London
• A.P. Letchford
  STFC/RAL/ISIS, Chilton, Didcot, Oxon
• J.K. Pozimski
  STFC/RAL, Chilton, Didcot, Oxon

A 4m-long, 324MHz four-vane RFQ, consisting of four coupled sections, is currently being designed for the Front End Test Stand (FETS) at RAL in the UK. A novel design method, integrating the CAD and electromagnetic design of the RFQ with beam dynamics simulations, is being used to optimise the design of the RFQ. Basic RFQ parameters are produced with the RFQSIM code. A full CAD model of the RFQ vane tips is produced in Autodesk Inventor, based upon these parameters. This model is then imported into a field mapping code to produce a simulation of the electrostatic field around the vane tips. This field map is then used to model the beam dynamics within the RFQ using General Particle Tracer (GPT). Previous studies have been carried out using field mapping in CST EM Studio. A more advanced technique using Comsol Multiphysics and Matlab, that more tightly integrates the CAD modelling, field mapping and beam dynamics simulations, is described. Results using this new method are presented and compared to the previous optimisation process using field maps from CST.

• J.J. Back
  University of Warwick, Coventry
• J. Alonso
  Fundación Tekniker, Elbr (Guipuzkoa)
• F.J. Bermejo
  Bilbao, Faculty of Science and Technology, Bilbao
• R. Enparantza
  Fundación TEKNIKER, Eibar (Gipuzkoa)
• D.C. Faircloth, A.P. Letchford
  STFC/RAL, Chilton, Didcot, Oxon
• C. Gabor
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon
• S.R. Lawrie
  STFC/RAL/ISIS, Chilton, Didcot, Oxon
• J. Lucas
  Elytt Energy, Madrid
• J.K. Pozimski, P. Savage
  Imperial College of Science and Technology, Department of Physics, London

The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory is intended to demonstrate the early stages of acceleration (0-3 MeV) and beam chopping required for high power proton accelerators, including proton drivers for pulsed neutron spallation sources and neutrino factories. A Low Energy Beam Transport (LEBT), consisting of three solenoids and four drift sections, is used to transport the H^- beam from the ion source to the FETS Radio Frequency Quadrupole. We present the status of the installation and commissioning of the LEBT, and compare particle dynamics simulations with preliminary measurements of the H^- beam transport through the LEBT.

• S.M.H. Alsari, J.K. Pozimski, P. Savage, O. Zorba
  Imperial College of Science and Technology, Department of Physics, London
• A.P. Letchford
  STFC/RAL/ISIS, Chilton, Didcot, Oxon

The Front End Test Stand (FETS) is an experiment based at the Rutherford Appleton Laboratory (RAL) in the UK. The test stand is being constructed in collaboration between STFC, Imperial College London, ASTeC, the University of Warwick and the Universidad del Pais Vasco. This experiment will design, build and test the first stages necessary to produce a very high quality, chopped H^- ion beam as required for the next generation of high power proton accelerators (HPPAs). HPPAs with beam powers in the megawatt range have many possible applications including drivers for spallation neutron sources, neutrino factories, accelerator driven sub-critical systems, waste transmuters and tritium production facilities. An automatic tuning system has been developed for the main 324MHz 4-vane RFQ accelerator and has been tested to fine tune the changes in the resonant frequency of a 324MHz 4-vane cold model RFQ, which been designed as part of the development of the test stand. This paper will present the electronics design of the automated tuning system along with the mechanical tuner structure. The design concepts will be discussed. Furthermore, results of the RF tuning would be presented.

• N. Solyak, E. Gianfelice-Wendt, I.G. Gonin, S. Kazakov, V.A. Lebedev, S. Nagaitsev, J.-F. Ostiguy, N. Perunov, G.V. Romanov, V.P. Yakovlev
  Fermilab, Batavia

The concept design of the 2.5 GeV superconducting CW linac of the Project X is discussed. The linac structure and break points for different cavity families are described. The results of the RF system optimization are presented as well as the lattice design and beam dynamics analysis.

• N. Solyak, I.G. Gonin, J.-F. Ostiguy, V.P. Yakovlev
  Fermilab, Batavia
• N. Perunov
  MIPT, Dolgoprudniy, Moscow Region

In this paper, we discuss beam dynamics optimization for a proposed continuous wave (CW) Project-X superconducting (SC) linac. This 2.6 GeV linac has an average current (over few microseconds) of 1 mA, with a pulsed current of up to 5-10 mA. The beam power is 2.6 MW. The CW linac consists of a low-energy 325 MHz section (2.5 MeV - 470 MeV) containing three families of SC single-spoke resonators and one family of triple-spoke resonators followed by a high-energy 1.3 GHz SC section (470 MeV - 2.6 GeV) containing squeezed elliptical (β=0.81) and ILC-type (β=1) cavities. Transverse and longitudinal dynamics in the CW linac are modeled assuming a peak current 10 mA. Different options for focusing structures are considered: solenoidal, doublet, and triplet focusing in the low-energy section; FODO and doublet focusing in the high energy section.

• M.A. Plum
  ORNL, Oak Ridge, Tennessee

The Spallation Neutron Source accelerator complex consists of a 2.5 MeV H^- front-end injector system, a 186 MeV normal-conducting linear accelerator, a 1 GeV superconducting linear accelerator, an accumulator ring, and associated beam transport lines. Since initial operation began in 2006, the beam power has been steadily increasing toward the design goal of 1.4 MW. In September 2009 the power surpassed 1 MW for the first time, and operation at the 1 MW level is now routine. The status of the beam power ramp-up program and present operational limitations will be described.

• M. Ichikawa, H. Fujisawa, Y. Iwashita, H. Tongu, S. Ushijima, M. Yamada
  Kyoto ICR, Uji, Kyoto

We aim to develop a small and high intensity proton source for a compact accelerator based neutron source. Because this proton source shall be located close to RFQ for simplification, ratio of H⁺ to molecular ions such as H²⁺ or H³⁺ must be large. Therefore, we selected an ECR ion source with permanent magnets as small and high intensity ion source. ECR ion sources can provide high H⁺ ratio because of their high plasma temperature. Using permanent magnets makes the ion source small and running cost low. Because there is no hot cathode, longer MTBF is expected. Usually, gas is fed into ion sources continuously, even if ion sources run in pulse operation mode. But, continuous gas flow doesn't make vacuum in good level. So, we decided to install pulse gas valve directly to the plasma chamber. Feeding the gas only when the ion source is in operation reduces the gas load to the evacuation system and the vacuum level can be kept high. Up to now, we developed the first and second model of the ion source. And the research is being conducted using the second model. Recent experimental results will be presented.