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linac

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MOAP01 Approach to a very high intensity beam at J-PARC proton, injection, hadron, rfq 1
 
  • Y. Yamazaki
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  
MOAP02 Recent Beam Commissioning Results from the Spallation Neutron Source target, extraction, proton, emittance 6
 
  • S. Henderson
    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. The beam commissioning campaign of the SNS accelerator complex, initiated in 2002, has been performed in seven discrete runs as each successive portion of the accelerator complex has been installed. The final beam commissioning run, in which beam was transported to the liquid mercury target was recently completed. In the course of beam commissioning, most beam performance parameters and beam intensity goals have been achieved at low duty factor. The beam performance and beam dynamics measurements of the linac and ring will be presented.  
 
MOAP03 Comparative Studies of Proton Accelerators for High Power Applications proton, target, factory, klystron 11
 
  • W.-T. Weng
    BNL, Upton, Long Island, New York
  There are many applications need high power proton accelerators of various kinds. However, each type of proton accelerator can only provide beam with certain characteristics, hence the match of accelerators and their application needs careful evaluation. In this talk, the beam parameters and performance limitations of linac, cyclotron, synchrotron, and FFAG accelerators will be studied and their relative merits for application in muon, neutron, neutrino, and ADS assessed in terms of beam energy, intensity, bunch length, repetition rate, and beam power requirements. A possible match between the applications and the accelerator of choice will be presented in a matrix form. The accelerator physics and technology issues and challenges involved will also be covered.  
 
MOBP01 ISIS Upgrades – A Status Report synchrotron, target, proton, rfq 20
 
  • D. J.S. Findlay
    CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
  Since 2002 several accelerator upgrades have been made to the ISIS spallation neutron source at the Rutherford Appleton Laboratory in the UK, and upgrades are currently continuing in the form of the Second Target Station Project. The paper will review the upgrade processes, and will also look forward to possible future schemes at ISIS beyond the Second Target Station.  
 
MOCP02 High-power accelerators in China: status and outlook target, proton, injection, dipole 39
 
  • J. Wei
    BNL, Upton, Long Island, New York
  • S. X. Fang, S. Fu
    IHEP Beijing, Beijing
  High intensity accelerator research is a relatively new subject in China. Recent program includes the accelerator-driven sub-critical power generation and the Beijing Spallation Neutron Source (BSNS) project. The Beijing Spallation Neutron Source (BSNS) is a newly approved project based on a H- linear accelerator and a rapid cycling synchrotron. During the past year, several major revisions were made on the design including the type of the front end, the linac frequency, the transport layout, the ring lattice, and the type of ring components. Possible upgrade paths were also laid out: based on an extension of the warm linac, the ring injection energy and the beam current could be raised doubling the beam power on target to reach 200 kW; an extension with a superconducting RF linac of similar length could raise the beam power near 0.5 MW. Based on these considerations, research and development activities are started. In this paper, we discuss the rationale of design revisions and summarize the recent works.  
 
TUAY01 Overview of proton driver studies for neutrino and muon factories proton, synchrotron, factory, target 64
 
  • W. Chou
    Fermilab, Batavia, Illinois
  There are a number of proton driver studies around the world: SPL at CERN, an 8 GeV SCRF linac at Fermilab, AGS upgrade at BNL, Proton Driver for the International Scoping Study on Neutrino Factories and Superbeams, FFAG based proton driver in Japan, etc. This talk will give an overview of them and compare their similarities and differences. Common R&D projects and possible inter-laboratory collaborations will be discussed.  
 
TUAY02 End-to-end beam dynamics for CERN Linac4 emittance, rfq, quadrupole, booster 79
 
  • A. M. Lombardi, G. Bellodi, J.-B. Lallement, S. Lanzone, E. Zh. Sargsyan
    CERN, Geneva
  • M. A. Baylac
    LPSC, Grenoble
  • R. Duperrier, D. Uriot
    CEA, Gif-sur-Yvette
  LINAC 4 is a normal conducting H- linac which aims to intensify the proton flux available for the CERN accelerator complex. This injector is designed to accelerate a 65 mA beam of H- ions up to 160 MeV for injection into the CERN Proton Synchrotron Booster. The acceleration is done in three stages : up to 3 MeV with a Radio Frequency Quadrupole (the IPHI RFQ) operating at at 352 MHz, then continued to 90 MeV with drift-tube structures at 352 MHz (conventional Alvarez and Cell Coupled Drift Tube Linac) and, finally, with a Side Coupled Linac at 700MHz. The accelerator is completed by a chopper line at 3 MeV and a transport and matching line to the PS booster. After the overall layout was determined based on general consideration of beam dynamics and RF, a global optimisation based on end-to-end simulation has refined some design choices. The results and lessons learned from the end-to-end simulations are reported in this paper.  
 
TUAY03 Design of the Driver Linac for the Rare Isotope Accelerator ion, rfq, heavy-ion, acceleration 89
 
  • P. N. Ostroumov, J. A. Nolen, K. W. Shepard
    ANL, Argonne, Illinois
  The proposed design of the Rare Isotope Accelerator (RIA) driver linac is based on cw fully superconducting 1.4 GV linac capable to accelerate uranium ions up to 400 MeV/u and protons to 1 GeV with 400 kW beam power. Extensive research and development effort has resolved many technical issues related to the construction of the driver linac and other systems of the RIA facility. Particularly, newly developed high-performance SC cavities will provide the required voltage for the driver linac using 300 cavities designed for six different geometrical betas. We are currently looking at alternatives for staging the facility to reduce the initial cost by about a factor of two. A possibility for the first stage includes ~850 MV driver linac to deliver uranium beams at 200 MeV/u and protons at 550 MeV. Thanks to successful tests of the front end systems, 400 kW beams can be obtained with increased intensities of heavy-ion beams from the ECR and higher rf power in the linac even at the first stage of the facility.  
 
TUAY04 Beam Dynamics Design of the PEFP 100 MeV Linac proton, quadrupole, emittance, rfq 99
 
  • J.-H. Jang, Y.-S. Cho, K. Y. Kim, Y.-H. Kim, H.-J. Kwon
    KAERI, Daejon
  The Proton Engineering Frontier Project (PEFP) is constructing a 100 MeV proton linac in order to provide 20 MeV and 100 MeV proton beams. The linac consists of a 50 keV proton injector including an ion source and a low energy beam transport (LEBT), a 3 MeV radio-frequency quadrupole (RFQ), a 20 MeV drift tube linac (DTL), a medium energy beam transport (MEBT), and the higher energy part (20 MeV ~ 100 MeV) of the 100 MeV DTL. The MEBT is located after the 20 MeV DTL to extract 20 MeV proton beams. The 20 MeV part of the linac was completed and is now under beam test. The higher energy part of the PEFP linac was designed to operate with 8% beam duty. This brief report discusses the design of the PEFP 100MeV linac as well as the MEBT.  
 
TUAY05 Application of the extreme value theory to estimate beam loss in an ion linac, using large scale Monte Carlo simulations beam-losses, quadrupole, simulation, beam-transport 107
 
  • R. Duperrier, D. Uriot
    CEA, Gif-sur-Yvette
  The influence of random perturbations of high intensity accelerator elements on the beam losses is considered. This paper presents the error sensitivity study which has been performed for the SPIRAL2 linac in order to define the tolerances for the construction. The proposed driver aims to accelerate a 5 mA deuteron beam up to 20 A. MeV and a 1 mA ion beam for q/A = 1/3 up to 14.5 A. MeV. It consists in an injector (two ECRs sources + LEBTs with the possibility to inject from several sources + Radio Frequency Quadrupole) followed by a superconducting section based on an array of independently phased cavities where the transverse focalization is performed with warm quadrupoles. The correction scheme and the expected losses are described. The Extreme Value Theory is used to estimate the expected beam losses. The described method couples large scale computations to obtain probability distribution functions. The bootstrap technique is used to provide confidence intervals associated to the beam loss predictions. With such a method, it is possible to measure the risk to loose a few watts in this high power linac (up to 200 kW).  
 
TUAZ06 Development of hybrid typoe carbon stripper foils with high durability against 1800K for RCS of J-PARC injection, vacuum, laser, ion 122
 
  • I. Sugai, Y. Arakida, Z. Igarashi, K. I. Ikegami, Y. Irie, H. Kawakami, M. Oyaizu, A. Takagi, Y. Takeda
    KEK, Ibaraki
  We have successfully made long-lived and hybrid , thick, boron mixed carbon stripper foils for high energy and high intensity accelerators. The foils were made by the controlled DC arc-discharge method, and the thickness is wide range from 50 to 600 ug/cm2. The lifetime of the foils was tested with use of 3.2 MeV Ne+DC beams of 2.5 uA, in which a significant of energy was deposited in the foils and thus we could simulate the condition by high power accelerator. The lifetime in maximum was shown to be extremely long, 102 and 410 times longer those of diamond and commercially available best carbon foils, respectively.  
 
TUBY02 Physics Design of a Multi-GeV Superconducting H-minus Linac focusing, rfq, proton, lattice 134
 
  • P. N. Ostroumov
    ANL, Argonne, Illinois
  • G. Apollinari, G. W. Foster, R. C. Webber
    Fermilab, Batavia, Illinois
  We discuss design of a pulsed linac based on 430 independently phased superconducting resonators for acceleration of 40 mA peak current H-minus beam up to 8-GeV. Most of the voltage gain (from ~410 MeV to 8 GeV) is provided by ILC cavities and squeezed ILC-style cavities operating at 1300 MHz. Significant cost savings are expected from the use of an rf power fan out from high-power klystrons to multiple cavities. The front end of the linac operating at 325 MHz will be based on multiple-spoke cavities. A room temperature section comprised of a conventional RFQ and 16 short normal conducting H-type resonators is proposed for the initial acceleration of an H-minus or proton beam up to 10 MeV. We have developed an accelerator lattice which satisfies the beam physics and engineering specifications.  
 
TUBY03 Error study of LINAC 4 simulation, emittance, quadrupole, proton 137
 
  • M. A. Baylac, J.-M. De Conto, E. Froidefond
    LPSC, Grenoble
  • E. Zh. Sargsyan
    CERN, Geneva
  LINAC 4 is a normal conducting H- linac which aims to intensify the proton flux available for the CERN accelerator complex. This injector is designed to accelerate a 65 mA beam up to 180 MeV. The linac consists of 4 different types of accelerating structures: the 352 MHz IPHI-RFQ, a 352 MHz 3-tank Drift Tube Linac, a 352 MHz Coupled Cavity Drift Tube Linac, and a 704.4 MHz Side Coupled Linac to boost the beam up to the final energy. As LINAC 4 is also designed as a pre-injector for a high power superconducting linac (3.5 GeV, 4 MW) the requirements on acceptable beam emittance growth, halo formation and particle loss are extremely tight. In order to determine the tolerances on the linac components, we examined the sensitivity of the structure to errors on the accelerating field and on the focusing quadrupoles. Simulations were performed between 3 and 180 MeV with the transport code TRACEWIN to evaluate the emittance growth, energy and phase jitter, halo formation of the transported beam and the amount of lost particles. We will present results on individual sensitivities to a single error, as well as the global impact of simultaneous errors on the beam quality. We will mention a f  
 
TUBY04 Operational flexibility of the SPL as proton driver for neutrino and other applications proton, target, factory, dipole 150
 
  • F. Gerigk, R. Garoby
    CERN, Geneva
  The pulse structure of proton linacs is determined by the linac energy, the RF system, and the maximum duty cycle of the source. Short bursts of protons in the microsecond range can be achieved by adding an accumulator ring and a reduction of the bunch length to the order of nanoseconds can be accomplished with an additional bunch compressor ring. The size of the rings along with their RF frequency determines the time structure of the proton driver output burst to hit the target. This pulse structure can be further modified using multiple fillings of the accumulator and compressor rings within one linac pulse. This paper illustrates the possible modes of operation of the SPL at CERN along with its limitations at various energies in combination with accumulator and compressor rings.  
 
TUBY05 A HIGH ENERGY GAIN DEUTERON LINAC simulation, rfq, emittance, lattice 156
 
  • J. Rodnizki, D. Berkovits, K. Lavie, A. Shor, Y. Yanai
    Soreq NRC, Yavne
  The beam dynamic simulation of the SARAF 40 MeV, 4 mA deuteron beam superconducting linac is extended in this work to 90 MeV for the EURISOL driver. It is designed for a high energy gain gradient with a moderate emittance growth, based on an end-to-end 3D simulation using a detailed 40 k macro particles distribution at the RFQ exit. The linac consists of 84 superconducting HWRs and one superconducting solenoid per two HWRs. The result average energy gain is 2.0 MeV/m. At the linac first cryomodule, where the  mismatch is high, the emittance growth is controlled by considering the bunch acceleration phase at each of the HWR coupled acceleration gaps.  
 
WEAX03 Space charge neutralization and its dynamic effects space-charge, electron, simulation, proton 187
 
  • R. Duperrier, N. Pichoff, D. Uriot
    CEA, Gif-sur-Yvette
  • A. BenIsmail
    LLR, Palaiseau
  High-power accelerators are being studied for several projects including accelerator driven neutron or neutrino sources. The low energy part of these facilities has to be carefully optimized to match the beam requirements of the higher energy parts. In this low energy part, the space charge self force, induced by a high intensity beam, has to be carefully controlled. This nonlinear force can generate a large and irreversible emittance growth of the beam. To reduce the space charge (SC), neutralization of the beam charge can be done by capturing some particles of the ionised residual gas in the vacuum chamber. This space charge compensation (SCC) regime complicates the beam dynamics study. This contribution aims to modelize the beam behavior in such a regime and to give order of magnitude to the linac designer for the neutralization rise time and the induced emittance growth.  
 
WEAZ01 Overview of beam loss mechanisms in injection and extraction injection, extraction, beam-losses, emittance 172
 
  • M. Tomizawa
    KEK, Ibaraki
  
WEBX04 Measurement strategy for the CERN Linac4 Chopper-line rfq, quadrupole, simulation, booster 262
 
  • J.-B. Lallement, K. Hanke, H. Hori, A. M. Lombardi, E. Zh. Sargsyan
    CERN, Geneva
  Linac4 is a new accelerator under study at CERN. It is designed to accelerate H- ions to 160 MeV of energy, for injection into the existing Proton Synchrotron Booster. The low energy section, comprising an H- ion source, a 352 MHz Radio Frequency Quadrupole and a 3 MeV chopper line will be assembled at CERN in the next years. Linac 4 is also designed as an injector for the SPL, a high power proton driver delivering 5MW at 3.5 GeV. In this case the beam losses must be limited to 1 W/m and therefore the formation of transverse and longitudinal halo at low energy becomes a critical issue which has to be measured and controlled. The chopper-line is composed of 11 quadrupoles, 3 bunchers and the chopper itself. Its beam dynamics will be characterized with specific detectors and diagnostic lines. In particular the transverse and longitudinal halo will be measured by a Beam Shape and Halo Monitor (BSHM) with a sensitivity of 10.000 particles per bunch and a time resolution of 2ns. In this paper we present the simulation work in preparation for the measurement campaign scheduled in 2008.  
 
THAY07 SC Spoke Cavity proton, ion, hadron, beam-loading 337
 
  • M. P. Kelly
    ANL, Argonne, Illinois
  Superconducting (SC) TEM-class spoke cavities have been an area of active research during the past decade with application to cw and pulsed ion linacs required for proposed facilities world-wide. Single- and multi-spoke geometries have been developed for use with ions over the full mass range and with velocities 0.2 < v/c < 0.8. Spoke cavities for this range, generally designed for 4 K operation, have several advantages over 2 K elliptical-cell cavities stemming mostly from the lower operating frequency. However, recent spoke-cavity results in 2 K operation, based on new and evolving cavity processing techniques such as clean assembly and hydrogen degassing, show very low rf losses even for high surface fields (EPEAK ~30 MV/m) required in operations. 2K results indicate even higher voltage gains per cavity with reduced heat loads are possible. Other implications of 2 Kelvin spoke cavity operation for ion linacs are discussed.  
 
THAZ02 SNS Commissioning Strategies and Tuneup Algorithms target, controls, injection, quadrupole 283
 
  • J. Galambos
    ORNL, Oak Ridge, Tennessee
  The Spallation Neutron Source (SNS) has been recently commissioned. The strategies for the initial beam commissioning of the superconducting linac (SCL) and storage ring will be discussed. The SCL commissioning had to accommodate an unanticipated wide range of cavity performance, compared to design expectations. Methods for setting cavity phases and determination of amplitudes will be discussed. The ring commissioning involved the usual establishment of a circulating beam, and then measurement and correction the tune and beta functions, all with a low intensity beam. Then the gradual increase of beam intensity and commissioning of RF and phase space painting were investigated. The methods to accomplish these tasks will be discussed. In general, the first order beam behavior is well understood. Key factors in the successful commissioning are: flexibility in accommodating beam conditions that are different from the design, good communication between the different groups, and attention to detail. Examples for these factors will be emphasized.  
 
THAZ06 Commissioning scenarios for the J-PARC accelerator complex injection, extraction, closed-orbit, acceleration 329
 
  • T. Koseki
    KEK, Ibaraki
  The J-PARC accelerator complex consists of a 400-MeV linac, a 3.0-GeV rapid-cycling synchrotron (RCS), a 50-GeV main ring (MR) and associated beam transport lines to experimental facilities, which use the 3- and 50-GeV proton beams. It is now under construction in the Tokai campus of JAEA as a joint project between JAEA and KEK. The beam commissioning of each accelerator is scheduled to start for linac in December 2006, RCS in September 2007 and MR in May 2008. The commissioning strategy for the accelerator complex will be presented.  
 
THBZ02 Commissioning strategies for J-PARC linac and L3BT injection, beam-transport, controls, quadrupole 347
 
  • M. Ikegami, S. Lee
    KEK, Ibaraki
  • Y. Kondo, T. Ohkawa
    JAEA, Ibaraki-ken
  • A. Ueno
    JAEA/LINAC, Ibaraki-ken
  We plan to start the beam commissioning of J-PARC linac with reduced energy of 181 MeV in the end of this year. Detailed commissioning strategies for the linac and the succeeding beam transport line, to which we refer as L3BT or Linac-to-3-GeV-synchrotron Beam Transport, will be presented in this talk. The emphasis will be put on the commissioning procedures for two debuncher cavities and a transverse collimator system located in L3BT, because they are key elements in determining the final beam quality at the injection point to the succeeding 3-GeV synchrotron. The unique design and features of the collimator system are also presented.  
 
THBZ05 The SNS linac commissioning – comparison of measurement and model* optics, simulation, emittance, lattice 353
 
  • D.-O. Jeon
    ORNL, Oak Ridge, Tennessee
  The Spallation Neutron Source linac commissioning was an excellent opportunity to benchmark the model with the measurement data for a high intensity linac. A new halo formation mechanism due to large beam eccentricity predicted by simulation was confirmed through a series of emittance measurement. Also the phase scan technique and the acceptance scan technique were benchmarked. Commissioning both demonstrated the validity of the model and revealed the shortfall of the model.  
 
THCX02 Cost Comparison of Linear and Circular Accelerators acceleration, RF-structure, synchrotron, factory 356
 
  • A. G. Ruggiero
    BNL, Upton, Long Island, New York
  A simple comparison of construction cost between a Linear and a Circular Accelerator is made. Two simplified models are proposed and studied. The comparison is made with the two major magnet and RF cavity components. An approximated criterion is found according to which the Circular Accelerator is indeed the more economical of the two provided that the beam circulates a minimum number of turns.  
 
FRAP02 Summary of Working Gropu B space-charge, simulation, resonance, beam-losses 363
 
  • S. M. Cousineau
    ORNL, Oak Ridge, Tennessee