THPD  —  Poster Session   (27-May-10   16:00—18:00)

Paper Title Page
THPD001 Electron Linac Photo-fission Driver for the Rare Isotope Program at TRIUMF 4275
 
  • S.R. Koscielniak, F. Ames, R.A. Baartman, P.G. Bricault, I.V. Bylinskii, Y.-C. Chao, K. Fong, R.E. Laxdal, M. Marchetto, L. Merminga, A.K. Mitra, I. Sekachev, V.A. Verzilov, V. Zvyagintsev
    TRIUMF, Vancouver
  • A. Chakrabarti, S. Dechoudhury, M. Mondal, V. Naik
    DAE/VECC, Calcutta
 
 

In July 2009 TRIUMF, in collaboration with the University of Victoria and other partners, was awarded Canadian federal government funds for the construction of an electron linear accelerator (e-linac) in support of its expanding rare isotope beam (RIB) program. The project anticipates Provincial funds for the construction of buildings to be announced in June 2010. TRIUMF has embarked on the detailed design for the 10 MeV Injector cryomodule and the first of two 20 MeV Accelerator cryomodules (ACMs), all rated up to 10 mA. The project first stage, ICM and ACM1, providing 25 MeV 4 mA is planned to be completed in November 2013. The injector is being fast tracked in a collaboration with the VECC in Kolkata, India. This paper gives an overview of the facility layout, and accelerator design progress including beam dynamics and cryomodule concept.

 
THPD002 Compact Solid State Direct Drive RF LINAC 4278
 
  • O. Heid, T.J.S. Hughes
    Siemens AG, Healthcare Technology and Concepts, Erlangen
 
 

The concept of a compact particle accelerator capable of delivering accelerating fields upto 100MV/m using a direct drive RF LINAC is explored. Such a machine consists of a succession of RF cavities with the RF power being supplied from a ring of solid state RF transistors placed around the cavity circumference. To achieve the required accelerating fields 3 core technologies are presented. (i) The solid-state transistors are used to drive the wall currents in the cavities so achieving a direct drive of the cavity. This allows unprecedented powers to be reached (>GW class) as well as enabling independent phase control of the individual cavities. Central to the implementation is the design of the RF drive consisting of distributed SiC vJFET modules delivering 750kA at 800V per cavity. (ii) A High Gradient Insulator structure is required to hold an electric field of >100MV/m. In contrast to a conventional HGI, the concept utilizes a vacuum insulated grading layer structure. (iii) A chopper and injection system allow the formation of proton bunches with a spatial emissivity <3ns and an injection field of up to 100MV/m.

 
THPD003 Test and Commissioning of the Third Harmonic RF System for FLASH 4281
 
  • E. Vogel, C. Albrecht, N. Baboi, C. Behrens, T. Delfs, J. Eschke, C. Gerth, M.G. Hoffmann, M. Hoffmann, M. Hüning, R. Jonas, J. Kahl, D. Kostin, G. Kreps, F. Ludwig, W. Maschmann, C. Mueller, P. Nommensen, J. Rothenburg, H. Schlarb, Ch. Schmidt, J.K. Sekutowicz
    DESY, Hamburg
  • H.T. Edwards, E.R. Harms, A. Hocker, T.N. Khabiboulline
    Fermilab, Batavia
  • M. Kuhn
    Uni HH, Hamburg
 
 

Ultra short bunches with high peak current are required for efficient creation of high brilliance coherent light at the free electron laser FLASH. They are obtained by a two stage transverse magnetic chicane bunch compression scheme based on acceleration of the beam off the rf field crest. The deviation of the rf field's sine shape from a straight line leads to long bunch tails and reduces the peak current. This effect will be eliminated by adding the Fermilab-built third harmonic superconducting accelerating module operating at 3.9 GHz to linearize the rf field. The third harmonic module also allows for the creation of uniform intensity bunches of adjustable length that is needed for seeded operation. This paper summarizes the results from the first complete rf system test at the crymodule test bench at DESY and the first experience gained operating the system with beam in FLASH.

 
THPD004 Design of the Positron Transport System for SuperKEKB 4284
 
  • N. Iida, T. Kamitani, M. Kikuchi, Y. Ogawa, K. Oide
    KEK, Ibaraki
 
 

SuperKEKB, the upgrade plan of KEKB, aims to boost the luminosity up to 8·1035 /cm2/s. The beam energy of the Low Energy Ring (LER) is 4 GeV for positrons, and that of the High Energy Ring is 7 GeV for electrons. SuperKEKB is designed to produce low emittance beams. The horizontal and vertical emittances of the injection beams are 4nm and 1nm, respectively, which are one or two orders smaller than those of KEKB. The positron injector system consists of the source, capture system, L-band and S-band linacs, collimators, an energy compression system (ECS), a 1-GeV damping ring, a bunch compression system (BCS), S-band and C-band linacs, and a beam transport line into the LER. This paper reports a design of the positron beam transport system from L-band linacs to SuperKEKB.

 
THPD006 Simultaneous Top-up Injection for Three Different Rings in KEK Injector Linac 4287
 
  • M. Satoh
    KEK, Ibaraki
 
 

The KEK injector linac sequentially provides beams, and transfers them to the following four storage rings: a KEKB low-energy ring (LER) (3.5 GeV/positron), a KEKB high-energy ring (HER) (8 GeV/electron), a Photon Factory ring (PF ring; 2.5 GeV/electron), and an Advanced Ring for Pulse X-rays (PF-AR; 3 GeV/electron). So far, beam injection to the PF ring and PF-AR is carried out twice a day, whereas the KEKB rings are operated in the continuous injection mode (CIM) so that the stored current remains almost constant. The KEK linac upgrade project has been started since 2004 so that the PF top-up and KEKB CIM can be performed at the same time. The aim of this upgrade is to change the linac parameters up to 50 Hz, which is the maximum linac beam repetition rate, by using a multi-energy-linac scheme. This upgrade has been successfully completed. The simultaneous top-up operation for three rings has stably been carried out since this April. We will report the simultaneous top-up injection for the KEKB and PF rings in detail.

 
THPD007 The Linac Upgrade Plan for SuperKEKB 4290
 
  • T. Sugimura, M. Akemoto, D.A. Arakawa, A. Enomoto, S. Fukuda, K. Furukawa, T. Higo, H. Honma, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, H. Nakajima, K. Nakao, Y. Ogawa, S. Ohsawa, M. Satoh, T. Shidara, A. Shirakawa, T. Suwada, T. Takenaka, Y. Yano, K. Yokoyama, M. Yoshida
    KEK, Ibaraki
 
 

The next generation B-factory 'SuperKEKB' project whose target luminosity is 8 ×1035 cm-2s-1 is under consideration. A 'nano-beam scheme' is introduced to the SuperKEKB. In the scheme, an electron beam (Energy = 7 GeV, Charge = 3-4 nC/bunch, Vertical emittance =2.8 x 10-5 m) and a positron beam (Energy = 4 GeV, Charge = 4 nC/bunch, Vertical emittance = 1.6 x 10-5 m), are required at the end of injector linac. They are quite challenging targets for the present linac. In order to meet the requirements, we will introduce some new components to the linac. They are a photo-cathode RF gun for an electron beam, a positron capture section using new L-band cavities, a newly designed positron-generation target system and a damping ring for a positron beam. This presentation shows a strategy of our injector upgrade.

 
THPD008 Upgrade of Cartridge-type Exchangeable Na2KSb Cathode RF Gun 4293
 
  • M. Uesaka, Y. Muroya, T. Ueda
    The University of Tokyo, Nuclear Professional School, Ibaraki-ken
  • K. Kanbe, K. Miyoshi
    University of Tokyo, Tokyo
 
 

We are commissioning the cathode, Na2KSb at the wavelength of 266, 400 nm with thermo-mechanically modified structure and improved vacuum system (2·10-08 Pa). We could improve RF reflection waveform and obtain the maximum energy of 22 MeV. We estimate the electrical field of 50 MV at the cathode. So far, we have obtained the quantum efficiencies of 1.1, 0.01% and the maximal charges of 4.6, 1 nC for 266, 400 nm. We are observing and checking carefully individual difference of QE of the cathodes for 266, 400 nm, and we have obtained 22 MeV energy. This new RF photocathode RF gun system has been already used for subpicosecond time-resolved radiation chemistry.

 
THPD009 Study on the High Order Modes of the 3.5cell Cavity at Peking University 4296
 
  • F. Wang, F.S. He, L. Lin, K. Zhao
    PKU/IHIP, Beijing
 
 

As part of the updated DC-SC injector, a 3.5cell cavity has been fabricated at Peking University, which includes two Coaxial High Order Mode (HOM) couplers. The effect of the HOM couplers has been studied by numerical simulation and measurement. The results are highly uniform and show that the two couplers do effectively damp the HOMs.

 
THPD011 Lattice Design for the LHeC Recirculating Linac 4298
 
  • Y. Sun, A.L. Eide, F. Zimmermann
    CERN, Geneva
  • C. Adolphsen
    SLAC, Menlo Park, California
 
 

In this paper, we present a lattice design for the Large Hadron Electron Collider (LHeC) recirculating Linac. The recirculating Linac consists of one roughly 3km long linac hosting superconducting RF (SRF) accelerating cavities, two arcs and one transfer line for the recirculation. Electron beam will have two passes in the SRF linac to get a maximum energy of 140 GeV, or have four passes with a maximum energy of 60 GeV (two for acceleration and two for deceleration) in the Energy Recovery Linac (ERL) option.

 
THPD012 Preliminary Study on Emittance Growth in the LHeC Recirculating Linac 4301
 
  • Y. Sun, F. Zimmermann
    CERN, Geneva
  • C. Adolphsen
    SLAC, Menlo Park, California
 
 

In this paper, we estimate the emittance growth in the LHeC recirculating Linac, the lattice design of which is presented in another paper of IPAC10 proceedings. The possible sources for emittance growth included here are: energy spread from RF acceleration in the SRF (superconducting RF) linac plus large chromatic effects from the lattice, synchrotron radiation (SR) fluctuations in the recirculating arcs. 6-D multi-particle tracking is launched to calculate the emittance from the statistical point of view. The simulation results are also compared with a theoretical estimation.

 
THPD013 Construction of a Thermionic RF Gun Linac System for Ultrashort Electron Beam 4304
 
  • W.K. Lau, J.H. Chen, J.-Y. Hwang, A.P. Lee, C.C. Liang, T.H. Wu
    NSRRC, Hsinchu
  • W.C. Cheng
    National Chiao Tung University, Hsinchu
  • N.Y. Huang
    NTHU, Hsinchu
 
 

A 25-30 MeV S-band linac system that equipped with thermionic cathode rf gun is being constructed at NSRRC for generation of ultrashort relativistitic electron beam. According to simulation studies, high quality GHz repetition rate electron pulses of about 50 pC as short as few tens fsec can be produced. This injector system will be used as the driver for experiments on fsec head-on inverse Compton scattering X-ray source and high power wake field microwave sources. The progress of our construction work will be presented.

 
THPD014 Muon Backgrounds in CLIC 4307
 
  • H. Burkhardt
    CERN, Geneva
  • G.A. Blair, L.C. Deacon
    Royal Holloway, University of London, Surrey
 
 

We report on a study of muon backgrounds in CLIC. For this we combined halo and tail generation using HTGEN with detailed tracking by BDSIM of impacting halo particles and resulting secondaries from the collimation spoilers to the detector.

 
THPD016 Upgrade of the Drive LINAC for the AWA Facility Dielectric Two-Beam Accelerator 4310
 
  • J.G. Power, M.E. Conde, W. Gai
    ANL, Argonne
  • Z. Li
    SLAC, Menlo Park, California
  • D. Mihalcea
    Northern Illinois University, DeKalb, Illinois
 
 

We report on the design of a 7 cell, standing wave, 1.3 GHz LINAC cavity and the associated beam dynamics studies for the upgrade of the drive beamline for the Argonne Wakefield Accelerator (AWA) facility. The LINAC design is a compromise between single bunch operation (100 nC @ 75 MeV) and minimizing the energy droop due to beam loadning along the bunch train during bunch train operation. The 1.3 GHz drive bunch train target parameters are: 75 MeV, 10-20 ns macropulse duration, 16x60nC microbunches; this is equivalent to a macropulse current and beam power of 80 Amps and 6 GW, respectively. Each LINAC structure accelerates approximately 1000 nC in 10 ns by a voltage of 11 MV at an RF power of 10 MW. Due to the short bunch train duration desired (~10 ns) and the existing frequency (1.3 GHz), compensation of the energy droop along the bunch train is difficult to accomplish with the two standard techniques: time-domain or frequency-domain beam loading compensation. Therefore, to minimize the energy droop, our design is based on a large stored energy LINACs. In this paper, we present our LINAC optimization method, detailed LINAC design, and beam dynamics studies of the drive beamline.

 
THPD019 Experimental Generation of Longitudinally-modulated Electron Beams using an Emittance-exchange Technique 4313
 
  • Y.-E. Sun, A.S. Johnson, A.H. Lumpkin, J. Ruan, R. Thurman-Keup
    Fermilab, Batavia
  • P. Piot
    Northern Illinois University, DeKalb, Illinois
 
 

We report our experimental demonstration of longitudinal phase space modulation using transverse-to-longitudinal emittance exchange technique. The experiment is carried out at the A0 photoinjector at Fermi National Accelerator Lab. A vertical multi-slit plate is inserted into the beamline prior to the emittance exchange, thus introducing beam horizontal profile modulation. After the emittance exchange, the longitudinal phase space coordinates (energy and time structures) of the beam are modulated accordingly. This is a clear demonstration of the transverse-to-longitudinal phase space exchange. In this paper, we present our experimental results on the measurement of energy and time profile of the electron beam, as well as numerical simulations of the experiment.

 
THPD020 Beam Dynamics Simulations of the NML Photoinjector at Fermilab 4316
 
  • Y.-E. Sun, M.D. Church
    Fermilab, Batavia
  • P. Piot
    Northern Illinois University, DeKalb, Illinois
 
 

Fermilab is currently constructing a superconducting RF (SRF) test linear accelerator at the New Muon Lab (NML). Besides testing SRF accelerating modules for ILC and Project-X, NML will also eventually support a variety of advanced accelerator R&D experiments. The NML incorporates a 40 MeV photoinjector capable of providing electron bunches with variable parameters. The photoinjector is based on the 1+1/2 cell DESY-type gun followed by two superconducting cavities. It also includes a magnetic bunch compressor, a round-to-flat beam transformer and a low-energy experimental area for beam physics experiments and beam diagnostics R&D. In this paper, we explore, via beam dynamics simulations, the performance of the photoinjector for different operating scenarios.

 
THPD022 FFAG Tracking with Cyclotron Codes 4319
 
  • M.K. Craddock
    UBC & TRIUMF, Vancouver, British Columbia
  • Y.-N. Rao
    TRIUMF, Vancouver
 
 

This paper describes tracking studies of non-scaling (NS) FFAGs using cyclotron codes in place of the more conventional lumped-element synchrotron codes. The equilibrium orbit code CYCLOPS determines orbits, tunes and period at fixed energies, while the general orbit code GOBLIN tracks a representative bunch of particles through the acceleration process. Results will be presented for the EMMA linear NS-FFAG under construction at Daresbury (10-20 MeV electrons), and for two non-linear NS-FFAG designs: Rees's isochronous IFFAG (8-20 GeV muons) and Johnstone's design for ADSR (250-1000 MeV protons). Our results are compared with those obtained using lumped-element codes. In the case of EMMA, results are presented for both the measured and design fields.

 
THPD023 Beam Dynamics Simulations regarding the Experimental FFAG EMMA, using the on-line code 4322
 
  • F. Méot
    CEA, Gif-sur-Yvette
  • Y. Giboudot
    Brunel University, Middlesex
  • D.J. Kelliher
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
  • T. Yokoi
    JAI, Oxford
 
 

The Electron Model for Many Applications FFAG (EMMA) has been the object of extensive beam dynamics simulations during its design and construction phases, using the ray-tracing code Zgoubi, which has been retained as the on-line simulation engine. On the other hand EMMA commissioning requires further advanced beam dynamics studies as well as on-line and off-line simulations. This contribution reports on some aspects of the studies so performed during the last months using Zgoubi.

 
THPD024 Recent Developments On The EMMA On-line Commissioning Software 4325
 
  • F. Méot
    CEA, Gif-sur-Yvette
  • J.S. Berg
    BNL, Upton, Long Island, New York
  • Y. Giboudot
    Brunel University, Middlesex
  • D.J. Kelliher, S. Machida
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
  • B.J.A. Shepherd
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • S.C. Tygier
    UMAN, Manchester
 
 

The EMMA (Electron Model for Many Applications) FFAG experiment at Daresbury will involve on-line modeling (a ‘‘Virtual EMMA'') based on stepwise ray-tracing methods. Various aspects of the code of concern and of its interfacing to real world - machine and users - are addressed.

 
THPD025 Recent Status of the MAMI-C Accelerator and First Experiences with the Energy Upgrade towards 1.6 GeV 4328
 
  • R.G. Heine, K. Aulenbacher, M. Dehn, H. Euteneuer, A. Jankowiak, P. Jennewein, H.-J. Kreidel, U. Ludwig-Mertin, O. Ott, G.S. Stephan, V. Tioukine
    IKP, Mainz
  • O. Chubarov
    Siemens AG, Erlangen
 
 

The university of Mainz institute for nuclear physics is operating the microtron cascade MAMI (Mainzer Mikrotron) since the late 1970ies. The microtron delivers a cw electron beam to users of the hadron physics community. The recent, fourth stage MAMI-C having a design energy of 1.5 GeV is operated since 2006*. This article deals with the recent developments and operational experiences of MAMI-C, as well as with the energy upgardes to 1.56 GeV** and as final step towards 1.6 GeV. The final increase of beam energy was due to user demands, since it is expected to raise the event rate of the eta prime production by an order of magnitude.


* A.Jankowiak, et al., EPAC08, Genoa, Italy, p.51 (MOZCM01)
** A. Jankowiak, et al., PAC09, Vancouver, Canada (WE6PFP111)

 
THPD026 Beam Optics and Magnet Design of Helium Ion FFAG Accelerator 4331
 
  • H.L. Luo, H. Hao, X.Q. Wang, Y.C. Xu
    USTC/NSRL, Hefei, Anhui
 
 

Fixed-Field Alternating Gradient (FFAG) accelerator accelerates in smaller costs heavy-ion with higher beam current than conventional circular accelerator, which could be more useful for the study of radioactive material. In this paper, the periodic focusing structure model of a Helium ion FFAG with a few MeV energy, which is contributed to study the impact of Helium embitterment on fusion reactor envelope material is proposed. A large-aperture magnet for Helium ion FFAG synchrotron is designed by using a 3D magnetic field simulation code OPERA-3D. The linear and nonlinear beam dynamics is studied through tracking the particle in the magnetic field generated by OPERA-3D.

 
THPD027 Orbit Correction in a non-scaling FFAG 4334
 
  • D.J. Kelliher, S. Machida
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
  • S.L. Sheehy
    JAI, Oxford
 
 

EMMA - the Electron Model of Many Applications - is to be built at the STFC Daresbury Laboratory in the UK and will be the first non-scaling FFAG ever constructed. The purpose of EMMA is to study beam dynamics in such an accelerator. The EMMA orbit correction scheme must deal with two characteristics of a non-scaling FFAG: i.e. the lack of a well defined reference orbit and the variation with momentum of the phase advance between lattice elements. In this study we present a novel orbit correction scheme that avoids the former problem by instead aiming to maximise both the symmetry of the orbit and the physical aperture of the beam. The latter problem is dealt with by optimising the corrector strengths over the energy range.

 
THPD028 Preparations for EMMA Commissioning 4337
 
  • B.D. Muratori, J.K. Jones, A. Kalinin, A.J. Moss, Y.M. Saveliev, R.J. Smith, S.L. Smith, S.I. Tzenov, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • G. Cox
    STFC/DL, Daresbury, Warrington, Cheshire
  • D.J. Holder
    Cockcroft Institute, Warrington, Cheshire
  • D.J. Kelliher, S. Machida
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
 
 

The first results from commissioning EMMA - the Electron Model of Many Applications- are summarised in this paper. EMMA is a 10 to 20 MeV electron ring designed to test our understanding of beam dynamics in a relativistic linear non-scaling fixed field alternating gradient accelerator (FFAG). EMMA will be the world's first non-scaling FFAG and the paper will outline the characteristics of the beam injected in to the accelerator as well as summarising the results of the extensive EMMA systems commissioning. The paper will report on the results of simulations of this commissioning and on the progress made with beam commissioning.

 
THPD029 Setting the Beam onto the Reference Orbit in Non Scaling FFAG Accelerators 4340
 
  • S.I. Tzenov, J.K. Jones, B.D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • Y. Giboudot
    Brunel University, Middlesex
 
 

Described in the paper are systematic procedures to inject and keep the beam on the reference trajectory for a fixed energy, as applied to the EMMA non scaling FFAG accelerator. The notion of accelerated orbits in FFAG accelerators has been introduced and some of their properties have been studies in detail.

 
THPD030 Characterisation of the ALICE Accelerator as an Injector for the EMMA NS-FFAG 4343
 
  • J.M. Garland, H.L. Owen
    UMAN, Manchester
  • J.W. McKenzie, B.D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
 
 

EMMA (Electron Model with Many Applications) is the first proof-of-principle non-scaling FFAG accelerator and is presently under construction at Daresbury Laboratory in the UK. To probe different parts of the bunch phase space during the acceleration from 10 to 20 MeV (which requires rapid resonance crossing), electron bunches are needed with sufficiently small emittance. To understand the phase space painting into the 3000 mm-mrad EMMA acceptance, we have modelled ALICE (Accelerators and Lasers in Combined Experiments) - which acts as an injector for EMMA - using GPT and compared the estimated emittances with measurements made with a variety of screen-based methods. Although the emittances are not yet as small as desired, we obtain reasonable agreement between simulation and measurement.

 
THPD031 Development of Tomographic Reconstruction Methods for Studies of Transverse Phase Space in the EMMA FFAG Injection Line 4346
 
  • M.G. Ibison, K.M. Hock, D.J. Holder, M. Korostelev
    Cockcroft Institute, Warrington, Cheshire
 
 

We present a simulation study on the reconstruction of the phase space distribution of a beam in the EMMA injection line. The initial step has been to use a Gaussian beam to calculate the phase space distribution and the horizontal and vertical beam projections which would be expected at a screen. The projections obtained from a range of optical configurations are provided as input for reconstructing the phase space distribution using a standard tomography method. The result from the reconstruction can be compared with the known phase space distribution. By taking into account the limited range of quadrupole strengths available, we can determine how practical limitations may affect the reconstruction.


*"EMMA: THE WORLD'S FIRST NON-SCALING FFAG," R. Edgecock, D. Kelliher, S. Machida, STFC/RAL, Didcot, UK et al. in Proceedings of EPAC08, Genoa, Italy

 
THPD033 Nonlinear Propagation of Laser Pulses in Plasmas: a Comparison between Numerical and Analytical Solutions 4349
 
  • A. Bonatto, R. Pakter, F.B. Rizzato
    IF-UFRGS, Porto Alegre
 
 

In this work the nonlinear relativistic propagation of intense lasers in plasmas is investigated. It is known that, under appropriate conditions, the ponderomotive force associated with the laser envelope can excite large amplitude electron waves (wakefields), which can be of interest for particle acceleration schemes. Numerical solutions showing some of the possible behaviors of this system are presented and compared to analytical ones, obtained through an effective potential approach using a one-dimensional Lagrangian formalism.

 
THPD034 Stable Proton Beam Acceleration from a Two-specie Ultrathin Foil Target 4352
 
  • T.P. Yu, M. Chen, A.M. Pukhov
    HHUD, Dusseldorf
  • T.P. Yu
    National University of Defense Technology, Changsha, Hunan
 
 

By using multi-dimensional particle-in-cell simulations, we investigate the stability of proton beam acceleration in a two-specie ultra-thin foil. In this two-specie regime, the lighter protons are initially separated from the heavier carbon ions due to their higher charge-to-mass ratio Z/m. The laser pulse is well-defined so that it doesn't penetrate the carbon ion layer. The Rayleigh-Taylor-like (RT) instability seeded at the very early stage then only degrades the acceleration of the carbon ions which act as a "cushion" for the lighter protons. Due to the absence of proton-RT instability, the produced high quality mono-energetic proton beams can be well collimated even after the laser-foil interaction concludes.

 
THPD035 Matching the Laser Generated p - bunch into a CH-DTL 4355
 
  • A. Almomani, M. Droba, U. Ratzinger
    IAP, Frankfurt am Main
  • I. Hofmann
    GSI, Darmstadt
 
 

The concept of laser acceleration of protons by Target Normal Sheath Acceleration TNSA from thin foils could be used to produce a high intensity proton bunch. This proton bunch could be injected into a linac at energies of ten to several tens MeV. A CH- structure is suggested as the linac structure because of its high gradient. The motivation for such a combination is to deliver single beam bunches with quite small emittance values of extremely high particle number - in the order of 10 billion protons per bunch. Optimum emittance values for linac injection are compared with available, laser generated beam parameters. Options and simulation tools for beam matching by pulsed solenoid and CH- structure using LASIN and LORASR codes are presented.

 
THPD036 Electron Acceleration by a Whistler Pulse 4358
 
  • R. Singh
    Indian Institute of Technology Delhi, Plasma Physics Group, New Delhi
  • A.K. Sharma
    Indian Institute of Technology Delhi, New Delhi
 
 

A Gaussian whistler pulse is shown to cause ponderomotive acceleration of electrons in a plasma when the peak whistler amplitude exceeds a threshold value. The threshold amplitude decreases with the ratio of plasma frequency to electron cyclotron frequency ωp / ωc. However above the threshold amplitude the acceleration energy decreases with ωp / ωc. The electrons gain velocities about twice the group velocity of the whistler. For acceleration of electrons one requires a whistler pulse of ω > ωc/2. It is seen that to enhance the energy gain the value of peak laser amplitude should be above a threshold value.

 
THPD037 Studies on Beam Loading in the CLIC RF Deflectors 4360
 
  • D. Alesini, C. Biscari, A. Ghigo
    INFN/LNF, Frascati (Roma)
 
 

After a short description of the Frequency Multiplication Scheme of the CLIC drive beam we present the impact of beam loading in the RF deflectors. First order scaling laws for the beam loading have been obtained to compare the effects in CLIC with those in the Test Facility CTF3. A dedicated tracking code has been written to study the multi-bunch multi-turn beam dynamics and the results are presented. Possible solutions to mitigate the beam loading effects such as the use of multiple RF deflectors are shown.

 
THPD038 Hybrid Schemes for the Post-acceleration of Laser Generated Protons 4363
 
  • A. Mostacci, M. Migliorati, L. Palumbo
    Rome University La Sapienza, Roma
  • D. Alesini, P. Antici
    INFN/LNF, Frascati (Roma)
  • L. Picardi, C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
 
 

Protons generated by the irradiation of a thin metal foil by a high-intensity short-pulse laser have shown to posses interesting characteristics in terms of energy, emittance, current and pulse duration. They might therefore become in the next future a competitive source to conventional proton sources. Previous theoretical and numerical studies already demonstrated the possibility of an efficient coupling between laser-plasma acceleration of protons with traditional RF based beam-line accelerator techniques. This hybrid proton accelerator would therefore benefit from the good properties of the laser-based source and from the flexibility and know-how of beam handling as given from RF based accelerator structure. The proton beam parameters of the source have been obtained from published laser interaction experimental results and are given as input to the numerical study by conventional accelerator design tools. In this paper we discuss recent results in the optimization and design of the such hybrid schemes in the context of proton accelerators for medical treatments.

 
THPD039 Proton Generation Driven by a High Intensity Laser Using a Thin-foil Target 4366
 
  • A. Sagisaka, P.R. Bolton, S.V. Bulanov, H. Daido, T. Esirkepov, T. Hori, S. Kanazawa, H. Kiriyama, K. Kondo, S. Kondo, M. Mori, Y. Nakai, M. Nishiuchi, K. Ogura, H. Okada, S. Orimo, A.S. Pirozhkov, H. Sakaki, F. Sasao, H. Sasao, T. Shimomura, A. Sugiyama, H. Sugiyama, M. Tampo, M. Tanoue, D. Wakai, A. Yogo
    JAEA, Kyoto
  • I.W. Choi, J. Lee
    APRI-GIST, Gwangju
  • H. Nagatomo
    ILE Osaka, Suita
  • K. Nemoto, Y. Oishi
    Central Research Institute of Electric Power Industry, Yokosuka-shi, Kanagawa
 
 

High-intensity laser and thin-foil interactions produce high-energy particles, hard x-ray, high-order harmonics, and terahertz radiation. A proton beam driven by a high-intensity laser has received attention as a compact ion source for medical applications. We have performed the high intensity laser-matter interaction experiments using a thin-foil target irradiated by Ti:sapphire laser (J-KAREN) at JAEA. In this laser system, the pulse duration is 40 fs (FWHM). The laser beam is focused by an off-axis parabolic mirror at the target. The estimated peak intensity is ~5x1019 W/cm2. We have developed on-line real time monitors such as a time-of-flight proton spectrometer which is placed behind the target and interferometer for electron density profile measurement of preformed plasma. We observed the maximum proton energy of ~7 MeV.

 
THPD040 Collimated Electron and Proton Beam from Ultra-intense Laser Interaction with a Rear Hole Target 4369
 
  • X.H. Yang, C.L. Tian, Y. Yin, T.P. Yu
    National University of Defense Technology, Changsha, Hunan
  • Y.Q. Gu
    Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang
  • S. Kawata, Y.Y. Ma
    Center for Optical Research and Education, Utsunomiya University, Utsunomiya
  • F.Q. Shao
    National University of Defense Technology, Graduate School, Changsha
  • H. Xu
    National University of Defense Technology, Parallel and Distributed Processing, Changsha
  • M.Y. Yu
    Ruhr-Universität Bochum, Bochum
 
 

We have proposed a scheme for the generation of collimated proton beams from the interaction of an ultra-intense laser pulse with a rear hole target, which is studied by a 2.5D particle-in-cell (PIC) code PLASIM. When an ultraintense short laser pulse irradiates on such a target, the hot electrons will expand fast into the hole from the inner surfaces of the hole, and strong longitudinal sheath electric field and transverse electric field are produced. However, the plasma in the corners expand slower and be compressed strongly, and then a strong plasma jet is sprayed out from the corner with very high speed, which is just like what happened in armor piercing bullet due to the cumulative energy effect. The two jets extend into the hole and focus along the axis of the hole. At last, a high quality collimated proton beam can be obtained near the end of the hole along the propagation axis. It's found that the beam can propagate over a much longer distance without divergence. The effect of the hole diameter on the collimated proton beam is also investigated. Such target may serve as an important source for collimated proton beam in practical applications.

 
THPD041 Evolution of Electron Bunches in a Combined Quasi-static and Laser Electric Field 4372
 
  • V.A. Papadichev
    LPI, Moscow
 
 

Short pulses of electrons of femtosecond and attosecond duration are necessary for numerous applications: studying fast processes in physics, chemistry, biology and medicine*. Previous calculations revealed that it is possible to obtain such short bunches by applying quasi-static electric voltage to a needle placed into a laser focus**,***. This paper presents results of computer simulation of the electron bunch evolution for various parameters of the problem (quasi-static and laser electric fields, radius of curvature of the needle, velocity of electron emission etc.). Simple model for analytical calculation of bunch evolution was elaborated to precisely assess its shortening in the case when one can neglect space-charge forces in the bunch. Influence of velocity dispersion in the bunch due to emission process is discussed and the way to optimize the bunching was proposed. Bunch dynamics accounting for space-charge forces was studied using analytical solution of equation of motion.


* P.Emma. Proc. EPAC04, p. 225, Lucerne, Suisse.
** V.A.Papadichev. Proc. EPAC08, p. 2812, Genoa, Italy.
*** V.A.Papadichev. Proc. EPAC08, p. 2815, Genoa, Italy.

 
THPD042 Dispersion Engineering and Disorder in Photonic Crystals for Accelerator Applications 4375
 
  • R. Seviour
    Lancaster University, Lancaster
 
 

The possibility of achieving higher accelerating gradients at higher frequencies with the reduction of the effect of HOMs, compared to conventional accelerating structures, is increasing interest in the possible use of Photonic Crystals (PC) for accelerator applications. In this paper we analyze how the properties of the lattice of a PC resonator can be engineered to give a specific band structure, and how by tailoring the properties of the lattice specific EM modes can either be confined or moved into the propagation band of the PC. We further go on to discuss the role of disorder in achieving mode confinement and how this can be used to optimize both the Q and the accelerating gradient of a PC based accelerating structure. We also examine the use of high disorder to give rise to Anderson Localization, which gives rise to exponential localization of an EM mode. Discussing the difference between the extended Bloch wave, which extends over the entire PC, and the Anderson localized mode.

 
THPD043 Metamaterial Mediated Inverse Cherenkov Acceleration 4378
 
  • Y.S. Tan
    Lancaster University, Lancaster
  • R. Seviour
    Cockcroft Institute, Lancaster University, Lancaster
 
 

In this paper we examine the effect of introducing an Electromagnetic metamaterial into a Travelling Wave structure to mediate inverse Cherenkov acceleration. Electromagnetic metamaterials are artificial materials that consist of macroscopic structures that yield an effective permittivity and permeability less than zero. The properties of metamaterials are highly frequency dependent and give rise to very novel dispersion relationships. We show that the introduction of a specifically designed metamaterial into the interaction region gives rise to a novel dispersion curve yielding a unique wave-particle interaction. We demonstrate that this novel wave-particle interaction gives rise energy exchange from wave to beam over an extended interaction regime. We also discuss the benefits and issues that arise from having a metamaterial in a high vacuum high power environment with a specific focus on the issue of loss in metamaterial structures.

 
THPD045 Fabrication of a Laser-based Microstructure for Particle Acceleration 4381
 
  • J. Zhou, J.C. McNeur, J.B. Rosenzweig, G. Travish
    UCLA, Los Angeles
  • R.B. Yoder
    Manhattanville College, Purchase, New York
 
 

The Micro-Accelerator Platform is an optical-wavelength microstructure for laser acceleration of particles, currently under development at UCLA. It is a slab-symmetric structure and can be constructed in layers using existing nanofabrication techniques. We present several possible fabrication techniques and preliminary experimental outcomes for manufacturing this structure.

 
THPD046 Initial Results on Electron Beam Generation using Pyroelectric Crystals 4384
 
  • U.H. Lacroix, D.M. Fong, G. Travish, N. Vartanian
    UCLA, Los Angeles
  • E.R. Arab
    PBPL, Los Angeles
  • R.B. Yoder
    Manhattanville College, Purchase, New York
 
 

Pyroelectric crystals, which produce large surface electric fields during heating and cooling, have been proposed as a mechanism for constructing a stand-alone electron beam source. We report on experimental tests of this concept, using a variety of field emission tips combined with a pyroelectric crystal to produce a low-energy electron beam during thermal cycling. The mechanism is suitable for generating very small electron bunches, with energies up to tens of kilovolts, for use in microaccelerator structures.

 
THPD047 A Tapered Dielectric Structure for Laser Acceleration at Low Energy 4387
 
  • J.C. McNeur, R. Dusad, Z.B. Hoyer, J.B. Rosenzweig, G. Travish, N. Vartanian, J. Xu, J. Zhou
    UCLA, Los Angeles
  • E.R. Arab
    PBPL, Los Angeles
  • R.B. Yoder
    Manhattanville College, Purchase, New York
 
 

This paper extends the physics of the Micro-Accelerator Platform (MAP), which is in development as an optical structure for laser acceleration of relativistic electrons. The MAP is a resonant, optical-scale, slab-symmetric device that is fabricated from dielectric materials using layer-deposition techniques. For stand-alone applications, low-energy electrons (beta ~ 0.3) must be synchronously accelerated to relativistic speeds for injection into the MAP. Even lower energies are desired for other particle species (e.g. protons or muons). In this paper, we present design and simulation studies on a tapered geometry and associated coupling scheme that can produce synchronous acceleration at beta < 1 within a MAP-like structure.

 
THPD048 First High-gradient Tests of the Single-cell SC Cavity with the Feedback Waveguide 4390
 
  • P.V. Avrakhov, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • M. Ge, I.G. Gonin, T.N. Khabiboulline, J.P. Ozelis, A.M. Rowe, N. Solyak, G. Wu, V.P. Yakovlev
    Fermilab, Batavia
  • J. Rathke
    AES, Medford, NY
 
 

Use of a superconducting travelling wave accelerating (STWA) structure with a small phase advance per cell rather than a standing wave structure may provide a significant increase in the accelerating gradient in the ILC linac. For the same surface electric and magnetic fields the STWA achieves an accelerating gradient 1.2 larger than TESLA-like standing wave cavities. In addition, the STWA allows longer acceleration cavities, reducing the number of gaps between them. However, the STWA structure requires a SC feedback waveguide to return the few hundreds of MW of circulating RF power from the structure output to the structure input. A test single-cell cavity with feedback was designed and manufactured to demonstrate the possibility of a proper processing to achieve a high accelerating gradient. The first results of high-gradient tests of a prototype 1.3 GHz single-cell cavity with feedback waveguide will be presented.

 
THPD050 A Proposed Experiment on the Proton Driven Plasma Wakefield Acceleration 4392
 
  • A. Caldwell, G.X. Xia
    MPI-P, München
  • R.W. Assmann, F. Zimmermann
    CERN, Geneva
  • K.V. Lotov
    BINP SB RAS, Novosibirsk
  • A.M. Pukhov
    HHUD, Dusseldorf
 
 

Proton driven plasma wakefield acceleration holds promise to accelerate a bunch of electrons to the energy frontier in a single acceleration channel. To verify this novel idea, a demonstration experiment is now being planned. The idea is to use the high energy proton bunches from the Super Proton Synchrotron (SPS) at CERN, to shoot them into a plasma cell and drive large amplitude of plasma wake. The interactions between the plasma and protons are simulated and the results are presented in this paper.

 
THPD051 Producing Short Proton Bunch for Driving Plasma Wakefield Acceleration 4395
 
  • G.X. Xia, A. Caldwell
    MPI-P, München
 
 

A high energy, intense and short proton bunch can be employed to excite an interesting plasma wakefield for the electron beam acceleration. To excite a large amplitude of plasma wave, a short driver is thus required. In this paper, several proton bunch compression scenarios are analyzed. A magnetic bunch compressor is designed to compress the SPS proton beam for the demonstration experiment at CERN. The simulation results of bunch compression are given.

 
THPD052 Manipulation of Negatively Charged Beams via Coherent Effects in Bent Crystals 4398
 
  • V. Guidi, E. Bagli, A. Mazzolari
    INFN-Ferrara, Ferrara
  • A.G. Afonin, Y.A. Chesnokov, V.A. Maisheev, I.A. Yazynin
    IHEP Protvino, Protvino, Moscow Region
  • S. Baricordi, P. Dalpiaz, M. Fiorini, D. Vincenzi
    UNIFE, Ferrara
  • D. Bolognini, S. Hasan, M. Prest
    Università dell'Insubria & INFN Milano Bicocca, Como
  • G. Della Mea, R. Milan
    INFN/LNL, Legnaro (PD)
  • A.S. Denisov, Yu.A. Gavrikov, Yu.M. Ivanov, L.P. Lapina, L.G. Malyarenko, V. Skorobogatov, V.M. Suvorov, S.A. Vavilov
    PNPI, Gatchina, Leningrad District
  • S. Golovatyuk, A.D. Kovalenko, A.M. Taratin
    JINR, Dubna, Moscow Region
  • A. Mattera
    INFN MIB, MILANO
  • W. Scandale
    CERN, Geneva
  • S. Shiraishi
    Enrico Fermi Institute, University of Chicago, Chicago, Illinois
  • E. Vallazza
    INFN-Trieste, Trieste
  • A. V. Vomiero
    INFM-CNR, Istituto Nazionale di Fisica della Materia - Consiglio Nazionale delle Ricerche, Brescia
 
 

New results in coherent interaction of negatively-charged particles with bent crystals showed unprecedentedly and significantly high efficiency to manipulate such beams, in the same way as for positively charged particles. Key feature under experimental attainment was the usage of high-quality suitably thin silicon crystals. We experimentally tested crystals Vs. 150 GeV negative pions at external lines of CERN SPS. We observed planar channeling at full deflection angle 30% high single-pass efficiency and large acceptance (about 20μrad). Moreover in the axial case, we reached more than 90% deflection efficiency and larger acceptance (about 60μrad). We also observed volume reflection in a bent crystal, at more than 70% single-pass efficiency with such a wide acceptance as the bending angle. At last, volume reflection by several planes in a single bent crystal was successfully tested with very high efficiency (about 80%). In summary both channeling and volume reflection modes appear to be useful technique for the manipulation of negatively charged beams, e.g. for collimation in the new generation of high intensity accelerators.


The UA9 collaboration

 
THPD053 Capture and Transport of Electron Beams from Plasma Injectors 4401
 
  • P. Antici, A. Mostacci
    INFN/LNF, Frascati (Roma)
  • C. Benedetti
    Bologna University, Bologna
  • M. Migliorati, L. Palumbo
    Rome University La Sapienza, Roma
 
 

Electron beams produced by laser-plasma interaction are attracting the interest of the conventional accelerator community. In particular Laser-accelerated electrons are particularly interesting as source, considering their high initial energy and their strong beam current. Moreover, the advantages of using laser-plasma electron beam can be expressed in terms of size and cost of the global accelerating infrastructure. However, improvements are still necessary since, currently, the many laser-accelerated beams are characterized by a large energy spread and a high beam divergence that degrades quickly the electron beam properties and makes those sources not suitable as a replacement of conventional accelerators. In this paper, we report on the progress of the study related to capture, shape and transport of laser generated electrons by means of tracking codes. Our study has focused on laser-generated electrons obtained nowadays by conventional multi hundred TW laser systems and on numerical predictions. We analyze different lattice structures, working on the optimization of the capture and transport of laser-accelerated electrons. Results and open problems are shown and discussed.

 
THPD054 Inverse Compton Scattering by Laser Accelerated Electrons and its Application to Standoff Detection of Hidden Objects 4404
 
  • Y. Kitagawa, K. Fujita, R. Hanayama, K. Ishii, Y. Mori
    GPI, Hamamatsu
  • T. Kawashima
    Hamamatsu Photonics K.K., Hamamatsu
  • H. Kuwabara
    IHI, Yokohama
 
 

A technique for remote detection of hidden objects is an urgent issue, but is not yet realized, because a source and a sensor must be located on the same side of the object. An ultra-intense laser can produce extremely short and directional radiations, that is the inverse Compton scatterings used for the backscattering system. We here demonstrate that the laser-wakefiled-accelerated 10-MeV electrons inversely scatter the same laser light to keV X-ray emissions. A 10 TW OPCPA Ti:sapphire laser BEAT ( 1J output, wavelength 815 nm, and pulse width 150fs) is divided to two beams. A 0. 8-J beam is focused to an entrance edge of helium gasjet to accelerate electrons via wakefield and the other 0.2-J beam is focused to the exit of the plasma channel from the opposite direction. A second harmonic probe light measured the channel density. To the upstream direction of the latter beam, a CdTe detector analyzed the Compton spectrum under a photon counting mode* in the range of 1 keV to 20 keV, which well agrees with that calculated from the obtained electron spectrum up to a few tens MeV. We also have observed that the emission is strong into the laser axis direction.


*H. Kuwabara, Y. Mori, Y. Kitagawa, 'Coincident Measurement of a Weakly Backscattered X-ray with a CPA Laser-Produced X-ray Pulse', Plasma Fusion Research: 3, 003-004 (2008).

 
THPD055 Improvement in Proton Beam Properties during Laser Acceleration and Propagation 4407
 
  • Y.Y. Ma, S. Kawata, K. Takahashi
    Center for Optical Research and Education, Utsunomiya University, Utsunomiya
  • Y.Q. Gu, Y.Y. Ma
    Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang
  • F.Q. Shao
    National University of Defense Technology, Graduate School, Changsha
  • Z.M. Sheng
    Shanghai Jiao Tong University, Shanghai
  • Y. Yin, T.P. Yu, D. F. Zhou
    National University of Defense Technology, Changsha, Hunan
  • M.Y. Yu
    Ruhr-Universität Bochum, Bochum
  • H.B. Zhuo
    National University of Defense Technology, Parallel and Distributed Processing, Changsha
 
 

Energetic protons of tens MeV or more produced by intense lasers have been observed in recent experiments and numerical simulations. Meanwhile, significant efforts have been made to improve the proton beam quality *,**,***. For most applications, it is important to improve the quality of the proton beam both during the production and during the propagation. Some schemes are proposed to improve the quality of the proton beam both during the production form the laser plasma interaction and during the propagation. The physics is investigated by 2D3V and 3D particle-in-cell codes PLASIM and PLASIM3D. In this paper, we propose to use an umbrella-like target to accelerate, and collimate protons. It is found that high intensity collimated MeV-proton beams can be produced ****. We also propose a scheme to generate quasi-monoenergetic proton beam from the interactions of an ultra-intense laser pulse and a thin tailored hole target. Particle simulation shows that a monoenergetic proton beam is generated from the hole. The propagation of a proton beam both in vacuum and in a plasma is also studied. Compared with the propagation in vacuum, the proton beam quality can be improved obviously.


* T. Toncian, et al. Science 312, 410(2006).
** B. M. Hegelich, et al. Nature 439, 441(2006).
*** H. Schwoerer, et al. Nature 439, 445(2006).
**** Y. Y. Ma et al., Phys Plasmas 16, 34502(2009).

 
THPD056 Experimental Program for the CLIC Test Facility 3 Test Beam Line 4410
 
  • E. Adli
    University of Oslo, Oslo
  • A.E. Dabrowski, S. Döbert, M. Olvegård, D. Schulte, I. Syratchev
    CERN, Geneva
  • R.L. Lillestol
    NTNU, Trondheim
 
 

The CLIC Test Facility 3 Test Beam Line is the first prototype for the CLIC drive beam decelerator. Stable transport of the drive beam under deceleration is a mandatory component in the CLIC two-beam scheme. In the Test Beam Line more than 50% of the total energy will be extracted from a 150 MeV, 28 A electron drive beam, by the use of 16 Power Extraction and Transfer structures. A number of experiments are foreseen to investigate the drive beam characteristics under deceleration in the Test Beam Line, including beam stability, beam blow up and the efficiency of the power extraction. General benchmarking of decelerator simulation and theory studies will also be performed. Specially designed instrumentation including precision BPMs, loss monitors and a time-resolved spectrometer dump will be used for the experiments. This paper describes the experimental program foreseen for the Test Beam Line, including the relevance of the results for the CLIC decelerator studies.

 
THPD057 The Analysis of Tunable Dielectric Loaded Wakefield Accelerating Structure of Rectangular Geometry 4413
 
  • I.L. Sheynman, A. Altmark, S. Baturin
    LETI, Saint-Petersburg
  • A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
 
 

The analysis of Vavilov-Cherenkov radiation generated by wide high current relativistic electronic bunch in a rectangular waveguide with multilayered dielectric filling is carried out. One ceramic layer of the structure possesses ferroelectric properties, which allow the waveguide frequency spectrum to be controlled by varying the permittivity of this ferroelectric layer by external electric field. On the basis of decomposition on orthogonal eigenmodes of a rectangular multilayered waveguide analytical expressions are received and numerical modeling of wakefield electromagnetic fields and the radial forces deflecting the bunch is spent.

 
THPD058 Definition of Focusing System Parameters on the Basis of the Analysis of a Transverse Bunch Dynamics in Dielectric Loaded Wakefield Accelerator 4416
 
  • I.L. Sheynman
    LETI, Saint-Petersburg
  • A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
 
 

The strong focusing of high current relativistic electron beams in multi-bunch wakefield acceleration is investigated. These beams are used for generating wake fields in dielectric loaded accelerating structures. We consider ramped charge distribution in the sequence of high current drive bunch. It is shown that the beam focusing system dumping beam break-up effect and elongating of a maximum distance the high current beam can travel determines the effectiveness of the energy transfer to the accelerated electron bunch. The optimal parameters of the focusing system on the basis of self-consistent transverse dynamics analysis are determined.

 
THPD059 The Status of Turkish Accelerator Center Project 4419
 
  • S. Ozkorucuklu
    SDU, Isparta
  • A. Aksoy, B. Ketenoğlu, O. Yavas
    Ankara University, Faculty of Engineering, Tandogan, Ankara
  • P. Arikan
    Gazi University, Faculty of Arts and Sciences, Teknikokullar, Ankara
  • O. Cakir, A.K. Çiftçi, R. Çiftçi, K. Zengin
    Ankara University, Faculty of Sciences, Tandogan/Ankara
  • H. Duran Yildiz
    Dumlupinar University, Faculty of Science and Arts, Kutahya
 
 

The status and road map of Turkish Accelerator Center (TAC) project is explained. TAC project is in third phase after feasibility and conceptual design phases with support of State Planning Organisation (SPO) of Turkey that the main aim of this phase is to complete of technical design report of TAC and to establish the first (test) facility. The first facility is planned as superconducting electron linac based IR FEL and bremsstrahlung facility. Third phase will be completed in 2013. It is planned that TAC will include a linac on ring type electron positron collider as a super charm factory, third and fourth generation light sources (SR and SASE FEL) and a proton facility. TAC collaboration is an inter-university collaboration of ten Turkish Universities under the coordination of Ankara University and TAC is a national project with international collaboration. In this study, the status of the project and the road map is explained with some results from design and construction studies.

 
THPD061 Nonlinear Theory of Wakefield Excitation in A Rectangular Multizone Dielectric Resonator 4422
 
  • G.V. Sotnikov, K.V. Galaydych
    NSC/KIPT, Kharkov
  • A.M. Naboka
    IERT, Kharkov
 
 

To excite intensive accelerating fields a multi-zone dielectric structures can be used*. As have shown already carried out researches, at their excitation by relativistic charged particle bunches the maximal amplitude of an accelerating field significantly depends on group velocity of energized waves. Till now these effects in wakefield multi-zone dielectric accelerators in details are not investigated. In addition the large charge of drive bunches requires the obligatory account of its space charge on bunch dynamics. To account the specified effects we built the nonlinear self-consistent theory of wake field excitation in the multilayered dielectric resonators. Expressions for excited fields, functionally depending on position of bunch particles in the resonator are found analytically. Excited fields are presented in the form of superposition solenoidal (LSE and LSM types) and potential fields. The nonlinear theory built in a general view is valid for any number of dielectric layers. Use of the constructed theory for the account of nonlinear and groups velocity effects is demonstrated on an example of 5-zone dielectric resonator with parameters close to experiment**.


* C. Wang et.al. In Proc. PAC 2005. IEEE, 2005, p. 1333.
** G.V.Sotnikov et.al. AIP Conf. proc. V.1086, p.415.

 
THPD062 Argonne Wakefield Accelerator Facility (AWA) Upgrades 4425
 
  • M.E. Conde, S.P. Antipov, W. Gai, R. Konecny, W. Liu, J.G. Power, Z.M. Yusof
    ANL, Argonne
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio
 
 

The AWA Facility is dedicated to the study of advanced accelerator concepts based on electron beam driven wakefields. The facility employs an L-band photocathode RF gun to generate high charge short electron bunches, which are used to drive wakefields in dielectric loaded structures, as well as in metallic structures. Accelerating gradients as high as 100 MV/m have been reached in dielectric structures, and RF pulses of up to 44 MW have been generated at 7.8 GHz. In order to reach higher accelerating gradients and higher RF power levels, several upgrades are underway: (a) a new RF gun with higher QE photocathode will replace the present drive gun; (b) the existing RF gun will generate a witness beam to probe the wakefields; (c) three new 25 MW L-band RF power stations will be added to the facility; (d) five additional linac structures will bring the beam energy up from 15 MeV to 75 MeV. The drive beam will consist of bunch trains of up to 32 bunches, with up to 60 nC per bunch. The goal of future experiments is to reach accelerating gradients of several hundred MV/m and to extract RF pulses with GW power level.

 
THPD063 Design and High Power Test of Photonic Bandgap Structures for Accelerator Applications 4428
 
  • B.J. Munroe, R.A. Marsh, M.A. Shapiro, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts
 
 

Photonic bandgap (PBG) structures show promising results for use in future collider applications. Both acceleration and wakefield damping have been demonstrated experimentally. The breakdown performance of a single cell PBG structure was tested at X-band at SLAC and found to have significant contributions from magnetic field effects. A new structure has been designed at 17.1 GHz to be tested at MIT to investigate the scaling of these and other breakdown effects with frequency. The 17.1 GHz structure will also use the open nature of the PBG lattice to greatly improve the breakdown diagnostics. Finally, a novel PBG structure has been designed for testing at SLAC using elliptical inner rods. This design significantly reduces the pulsed heating in the structure and should therefore improve the breakdown performance.

 
THPD066 Observation of Wakefields in a Beam-Driven Photonic Band Gap Accelerating Structure 4431
 
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio
  • S.P. Antipov, M.E. Conde, W. Gai, F. Gao, J.G. Power, Z.M. Yusof
    ANL, Argonne
  • H. Chen, C.-X. Tang, S.X. Zheng
    TUB, Beijing
  • P. Xu
    Tsinghua University, Beijing
 
 

Wakefield excitation has been experimentally studied in a 3-cell X-band standing wave Photonic Band Gap (PBG) accelerating structure. Major monopole (TM01- and TM02-like) and dipole (TM11- and TM12-like) modes were indentified and characterized by precisely controlling the position of beam injection. The quality factor Q of the dipole modes was measured to be ~10 times smaller than that of the accelerating mode. A charge sweep, up to 80 nC, has been performed, equivalent to ~30 MV/m accelerating field on axis. A variable delay low charge witness bunch following a high charge drive bunch was used to calibrate the gradient in the PBG structure by measuring its maximum energy gain and loss. Experimental results agree well with numerical simulations.

 
THPD067 The First Experiment of a 26 GHz Dielectric Based Wakefield Power Extractor 4434
 
  • C.-J. Jing, F. Gao, A. Kanareykin, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  • M.E. Conde, W. Gai, R. Konecny, J.G. Power
    ANL, Argonne
 
 

High frequency, high power rf sources are needed for many applications in particle accelerators, communications, radar, etc. We have developed a 26GHz high power rf source based on the extraction of wakefields from a relativistic electron beam. The extractor is designed to couple out rf power generated from a high charge electron bunch train traversing a dielectric loaded waveguide. The first high beam experiment has been performed at Argonne Wakefield Accelerator facility. The experimental results successfully demonstrate the 15ns 26GHz rf pulse generated from the wakefield extractor with a bunch train of 16 bunches. Meanwhile, ~ 30MW short rf pulse has been achieved with a bunch train of 4 bunches. Beam Breakup has prevented charge transport through the power extractor beyond 10nC. We are doing simulations and developing methods to alleviate the BBU effect.

 
THPD068 Experiment on a Tunable Dielectric-Loaded Accelerating Structure 4437
 
  • C.-J. Jing, A. Kanareykin, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  • M.E. Conde, W. Gai, J.G. Power
    ANL, Argonne
  • E. Nenasheva
    Ceramics Ltd., St. Petersburg
 
 

Dielectric-Loaded Accelerating (DLA) structures are generally lack of approaches to tune frequency after the fabrication. A tunable DLA structure has been developed by using an extra nonlinear ferroelectric layer. Dielectric constant of the applied ferroelectric material is sensitive to temperature and DC voltage. Bench test shows the +14MHz/°C, and 6MHz frequency tuning range for a 25kV/cm of DC bias field. A beam test is planned at Argonne Wakefield Accelerator facility before the IPAC conference. Detailed results will be reported.

 
THPD069 Studies of Nonlinear Media with Accelerator Applications 4440
 
  • P. Schoessow, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • S. Baturin
    LETI, Saint-Petersburg
  • V.P. Yakovlev
    Fermilab, Batavia
 
 

Materials possessing variations in the permittivity as a function of the electric field exhibit a variety of phenomena for electromagnetic wave propagation such as frequency multiplication, wave steepening and shock formation, solitary waves, and mode mixing. New low loss nonlinear microwave ferroelectric materials present interesting and potentially useful applications for both advanced and conventional particle accelerators. Accelerating structures (either wakefield-based or driven by an external rf source) loaded with a nonlinear dielectric may exhibit significant field enhancements. In this paper we will explore the large signal permittivity of these new materials and applications of nonlinear dielectric devices to high gradient acceleration, rf sources, and beam manipulation. We describe planned measurements using a planar nonlinear transmission line to characterize in detail the electric field dependence of the permittivity of these materials. We will present a concept for a nonlinear transmission line that can be used to generate short, high intensity rf pulses to drive fast rf kickers.

 
THPD070 Numerical and Experimental Studies of Dispersive, Active, and Nonlinear Media with Accelerator Applications 4443
 
  • P. Schoessow, C.-J. Jing, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • S.P. Antipov
    ANL, Argonne
 
 

Current advanced accelerator modeling applications require a more sophisticated treatment of dielectric and paramagnetic media properties than simply assuming a constant permittivity or permeability. So far active media have been described by a linear, frequency-dependent, single-frequency, scalar dielectric function.  We have been developing algorithms to model the high frequency response of dispersive, active, and nonlinear media. The work described also has applications for modeling of other electromagnetic problems involving realistic dielectric and magnetic media. Results to be reported include treatment of multiple Lorentz resonances based on auxiliary differential equation, Fourier, and hybrid approaches. We will also report on recent measurements of paramagnetic active microwave materials using EPR spectroscopy. Comparison of the results to numerical simulations will be presented.

 
THPD072 Laser Energy Conversion to Solitons and Monoenergetic Protons in Near-critical Hydrogen Plasma 4446
 
  • I. Pogorelsky, M. Babzien, M.N. Polyanskiy, V. Yakimenko
    BNL, Upton, Long Island, New York
  • N. Dover, Z. Najmudin, C.A.J. Palmer, J. Schreiber
    Imperial College of Science and Technology, Department of Physics, London
  • G. Dudnikova
    UMD, College Park, Maryland
  • M. Ispiryan, P. Shkolnikov
    Stony Brook University, StonyBrook
 
 

Recent theoretical and experimental studies point to better efficiency of laser-driven ion acceleration when approaching the critical plasma density regime. Simultaneously, this is the condition for observing solitons: "bubble"-like quasi-stationary plasma formations with laser radiation trapped inside. Exploring this regime with ultra-intense solid state lasers is problematic due to the lack of plasma sources and imaging methods at ~1021/cc electron density. The terawatt picosecond CO2 laser operated at Brookhaven's Accelerator Test Facility offers a solution to this problem. At 10 μm laser wavelength, the CO2 laser shifts the critical plasma density to 1019/cc which is attainable with gas jets and can be optically probed with visible light. Capitalizing on this approach, we focused a circular-polarized CO2 laser beam with a0=0.5 onto a hydrogen gas jet and observed monoenergetic proton beams in the 1 MeV range. Simultaneously, the laser/plasma interaction region has been optically probed with a 2nd harmonic picosecond Nd:YAG laser to reveal stationary soliton-like plasma formations. 2D PIC simulations agree with experimental results and aid in their interpretation.

 
THPD073 Acceleration Module in Linear Induction Accelerator 4449
 
  • S. Wang, J. Deng
    CAEP/IFP, Mainyang, Sichuan
 
 

Linear Induction Accelerator (LIA) is a unique type of accelerator, which is capable to accelerate kilo-Ampere beam current to tens of MeV. The LIA acceleration modules, filled with ferrite or ferromagnetic toroid cores, can be conveniently stacked to obtain high energy. During the evolution of LIA, several models for the LIA acceleration module and the function of the cores have been proposed. Authors of this paper surveyed these models and tried to bridged them to form a consistent understanding of the LIA acceleration module. The unified understanding should be helpful in the further development and design of the LIA acceleration module.

 
THPD074 Using Project X as a Proton Driver for Muon Colliders and Neutrino Factories 4452
 
  • G. Flanagan, R.J. Abrams, C.M. Ankenbrandt, M.A.C. Cummings, R.P. Johnson
    Muons, Inc, Batavia
  • M. Popovic
    Fermilab, Batavia
 
 

The designs of accelerator systems that will be needed to transform Fermilab's Project X into a high-power proton driver for a muon collider and/or a neutrino factory are discussed. These applications require several megawatts of beam power delivered in tens or hundreds of short multi-GeV bunches per second, respectively. Project X may require a linac extension to higher energy for this purpose. Other major subsystems that are likely to be needed include storage rings to accumulate and shorten the proton bunches and an external beam combiner to deliver multiple bunches simultaneously to the pion production target.

 
THPD076 Transverse Coupling Compensation at the UVX LNLS Storage Ring 4455
 
  • X.R. Resende, L. Liu
    LNLS, Campinas
 
 

In this paper we report on recent developments in transverse coupling characterization and compensation in the UVX storage ring at the Brazilian Synchrotron Light Laboratory (LNLS). We have designed and manufactured a compact skew quadrupole with which it was possible to completely compensate coupling introduced by insertion devices (IDs) in the ring.

 
THPD077 Linear Collider Test Facility: Twiss Parameter Analysis at the IP/Post-IP location of the ATF2 beam line 4458
 
  • B. Bolzon, A. Jeremie
    IN2P3-LAPP, Annecy-le-Vieux
  • S. Bai
    IHEP Beijing, Beijing
  • P. Bambade
    KEK, Ibaraki
  • G.R. White
    SLAC, Menlo Park, California
 
 

At the first stage of the ATF2 beam tuning, vertical beam size is usually bigger than 3um at the IP. Beam waist measurements using wire scanners and a laser wire are usually performed to check the initial matching of the beam through to the IP. These measurements are described in this paper for the optics currently used (βx=4cm and βy=1mm). Software implemented in the control room to automate these measurements with integrated analysis is also described. Measurements showed that beta functions and emittances were within errors of measurements when no rematching and coupling corrections were done. However, it was observed that the waist in the horizontal (X) and vertical (Y) plane was abnormally shifted and simulations were performed to try to understand these shifts. They also showed that multiknobs are needed in the current optics to correct simultaneously αx, αy and the horizontal dispersion (Dx). Such multiknobs were found and their linearity and orthogonality were successfully checked using MAD optics code. The software for these multiknobs was implemented in the control room and waist scan measurements using the αy knob were successfully performed.

 
THPD078 A Non Invasive Technique for the Transverse Matching in a Periodic Focusing Channel of a Linac 4461
 
  • R.D. Duperrier, D. Uriot
    CEA, Gif-sur-Yvette
 
 

A main interest in the high intensity ion linacs is the control of the particle loss in the vacuum chamber. A extremely low fraction of the beam (10-4 or 10-7) is sufficient to complicate the hands on maintenance in such accelerator. Beam mismatching being a major source of halo, it is proposed a non invasive technique to adapt the beam to a periodic focusing channel of a linac based on a FDO of FODO lattice. It is demonstrated that only the matched beam can correspond to a particular signature of the quadrupolar moment of the Beam Positions Monitors. This technique allows also to measure the emittance value or evolution along the channel.

 
THPD079 Optical Studies for the Super Separator Spectrometer S3 4464
 
  • D. Boutin, M. Authier, F. Dechery, O. Delferrière, A. Drouart, J. Payet, D. Uriot
    CEA, Gif-sur-Yvette
  • M. Amthor, H. Savajols, M.-H. Stodel
    GANIL, Caen
  • S.L. Manikonda, J.A. Nolen
    ANL, Argonne
 
 

S3 (Super Separator Spectrometer) [1] is a future device designed for experiments with the high intensity heavy ion stable beams of SPIRAL2 [2] at GANIL (Caen, France). It will include a target resistant to these very high intensities, a first stage momentum achromat for primary beam extraction and suppression, a second stage mass spectrometer and a dedicated detection system. This spectrometer includes large aperture quadrupole triplets with embedded multipolar corrections. To enable the primary beam extraction one triplet has to be opened on one side, which requires an appropriate design of such a multipolar magnet. The final mass separation power required for S3 needs a careful design of the optics with a high level of aberration correction. Multiple symmetric lattices were studied for this purpose. A 4-fold symmetric lattice and the achieved results are described in this paper.


[1] A. Drouart et al., Nucl. Phys. A 834 (2010) 747c. [2] SPIRAL2, http://pro.ganil-spiral2.eu/spiral2

 
THPD080 Coupling Measurements in ATF2 Extraction Line 4467
 
  • C. Rimbault
    LAL, Orsay
  • S. Kuroda, T. Tauchi, N. Terunuma
    KEK, Ibaraki
  • G.R. White, M. Woodley
    SLAC, Menlo Park, California
 
 

The purpose of ATF2 is to deliver a beam with stable very small spotsizes as required for future linear colliders such as ILC or CLIC. To achieve that, precise controls of the aberrations such as dispersion and coupling are necessary. Theoretically, the complete reconstruction of the beam matrix is possible from the measurements of horizontal, vertical and tilted beam sizes, combining skew quadrupole scans at several wire-scanner positions. Such measurements were performed in the extraction line of ATF2 in May 2009. We present analysis results attempting to resolve the 4X4 beam matrix and discuss the experimental limitations of 4D emittance measurements with wire scanners.

 
THPD081 Reducing Energy Spread of the Beam by Non-isochronous Recirculation at the S-DALINAC 4470
 
  • F. Hug, A. Araz, R. Eichhorn, N. Pietralla
    TU Darmstadt, Darmstadt
 
 

The Superconducting Linear Accelerator S-DALINAC at the University of Darmstadt/ Germany is a recirculating Linac with two recirculations. Currently acceleration in the Linac is done on crest of the acceleration field using the maximum of the field in every turn. The recirculation of the beam is done isochronous without any longitudinal dispersion. In this recirculation scheme the energy spread of the resulting beam is determined by the stability of the used RF system. In this work we will present a new non-isochronous recirculation scheme, which uses longitudinal dispersion in the recirculations and an acceleration on edge of the accelerating field as it is done in microtrons. We will present beam dynamic calculations which show the usability of this system even in a Linac with only two recirculations and first measurements of longitudinal dispersion using RF monitors.

 
THPD082 Beam Accumulation in a Stellarator Type Storage Ring 4473
 
  • M. Droba, N.S. Joshi, O. Meusel, H. Niebuhr, U. Ratzinger
    IAP, Frankfurt am Main
 
 

The stellarator-type storage ring for multi- Ampere proton and ion beams with energies in the range of 100 AkeV to 1AMeV was designed. The main idea for beam confinement with high transversal momentum acceptance was presented in EPAC06 and EPAC08. Stable beam transport in opposite directions is possible through the same aperture with two crossing points along the structure. Elsewhere the beams are separated by the RxB drift motion in curved sections. The space charge compensation through the trapped or circulated electrons will be discussed. This ring is typically suited for experiments in plasma physics and nuclear astrophysics. Here we present the complete simulations for optimization of ring geometry, a stable beam confinement and developments in beam injection.

 
THPD083 Apochromatic Beam Transport in Drift-Quadrupole Systems 4476
 
  • V. Balandin, R. Brinkmann, W. Decking, N. Golubeva
    DESY, Hamburg
 
 

A straight drift-quadrupole system, though not being an achromat, can transport certain incoming beam ellipses without introducing first-order chromatic distortions. Several examples of such apochromatic beam transport are available in the literature. In this paper we show that the possibility of apochromatic focusing is a general property: For every drift-quadrupole system there exist an unique set of Twiss parameters (apochromatic Twiss parameters), which will be transported through that system without first order chromatic distortions. Moreover, we prove that at the same time the apochromatic Twiss parameters bring the second order effect of the betatron oscillations on the shift of the average bunch path length to the minimal possible value and also minimize the effect of betatron oscillations on bunch lengthening for Gaussian beam. As an example we consider the application of the apochromatic focusing concept to the design of matching sections and phase shifter of the post-linac collimation section of the European XFEL Facility.

 
THPD084 Two Cell Repetitive Achromats and Four Cell Achromats Based on Mirror Symmetry 4479
 
  • V. Balandin, R. Brinkmann, W. Decking, N. Golubeva
    DESY, Hamburg
 
 

An achromat is a focusing system, in which as large a number of higher order aberrations as possible is canceled by symmetries of the linear optics and the rest is corrected by the usage of third and higher order multipoles. The first achromats ever considered were repetitive achromats, in which the cancellation of higher order aberrations relies on appropriate selection of cell tunes. Later on achromats, employing mirror symmetry, were also developed. In this paper we remove one superfluous constraint on the linear optics in the theory of four cell mirror symmetric achromats, make an accurate consideration of two cell repetitive achromats, and compare the number of multipoles required for each of those achromats. Moreover, we contribute a point of view, from which both approaches to the achromat design become identical. As a practical application we consider the design of the arcs of the post-linac collimation section of the European XFEL Facility.

 
THPD085 Correction of the Linear Optics at PETRA III 4482
 
  • J. Keil, K. Balewski
    DESY, Hamburg
 
 

PETRA III is a 6 GeV third generation light source located at DESY/Hamburg. The former pre-accelerator of HERA has been converted in 2007/2008 into a high brilliance synchrotron light source with an emittance of 1 nm*rad. The commissioning of PETRA III started in 2009. PETRA III is like other third generation light sources very sensitive to errors of the linear optics. Gradient errors reduce the dynamic aperture, increase the emittance and change the beam size. The correction of the optics is based on orbit response matrix data which were analyzed both with the program LOCO and with a fit of the beta-functions and phase-functions at BPMs and correctors. Initial results of the modelling of the machine and the correction of the linear optics functions will be presented.

 
THPD086 Measurement and Correction of Transverse Dispersion in PETRA III 4485
 
  • G.K. Sahoo, K. Balewski, W. Decking, J. Keil
    DESY, Hamburg
 
 

PETRA III is a 6GeV positron light source with a design horizontal beam emittance of 1nm.rad and 1% emittance coupling. This low emittance is achieved with proper correction of horizontal dispersion to its theoretical values in the arcs as well as dispersion free sections. The spurious vertical dispersion, arising due to misalignment and rotational errors of the magnets is also duly corrected as this contributes to the vertical beam size of the photon beam. Here we discuss the method taken to correct the horizontal dispersion using a combined orbit and dispersion correction scheme. In the vertical plane the same procedure can be used as that of horizontal plane or only the dispersion can be corrected using dedicated skew quadrupoles to millimeter level after orbit correction has been done. In this paper we present the methods used and results obtained in correction of dispersions in transverse planes.

 
THPD087 Potential Forms for Electrostatic and Magnetic Cylindrical Lens and Tracking of Charged Particle 4488
 
  • M.H. Rashid, R.K. Bhandari, C. Mallik
    DAE/VECC, Calcutta
 
 

A cylindrical lens is mainly used for focusing and transporting low energy beam. Some analytical forms of scalar potential have been formulated to evaluate electric and magnetic field and its derivatives on the central axis, which help in evaluation of potential and field in the region about the central axis. They are, subsequently, used to analytically find out the optical properties of a lens as well as in tracking of charged particles. It turns into a tool to design an electrostatic or a magnetic cylindrical lens. A section-technique has been developed to evaluate the optical cardinal points of a thick lens very accurately. Smooth profiles of the field and potential along the axis are divided into large number of small stepped profile. Each step represents a weak thin lens as change in radial movement is very small. The effect of the individual weak lenses is evaluated and combined by matrix multiplication method to get optical property of the thick lens. The obtained values are verified by exactly tracking the particles by solving the Lorentz equation of motion of charged particle in electric or magnetic field.

 
THPD088 Study of Coupler's Effects on ILC Like Lattice 4491
 
  • A. Saini
    University of Delhi, Delhi
  • A. Latina, A. Lunin, K. Ranjan, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia
 
 

It is well known that insertion of a coupler into a RF cavity breaks the rotational symmetry of the cavity, resulting in an asymmetric field. This asymmetric field results in a transverse RF Kick. This RF kick transversely offsets the bunch from the nominal axis & it depends on the longitudinal position of the particle in the bunch. Also, insertion of coupler generates short range transverse wake field which is independent from the transverse offset of the particle. These effects cause emittance dilution and it is thus important to study their behavior & possible correction mechanisms. These coupler effects, i.e. coupler's RF kick & coupler's wake field are implemented in a beam dynamics program, Lucretia. Simulations are performed for main linac & bunch compressor of International Linear Collider (ILC) like lattices. Results are compared with Placet results & a good agreement has been achieved.

 
THPD089 Analytical Formula for the Transient Bunch Lengthening by a Betatron Motion along Bending Sections 4494
 
  • Y. Shoji
    NewSUBARU/SPring-8, Laboratory of Advanced Science and Technology for Industry (LASTI), Hyogo
 
 

A simple analytical formula for the transient bunch lengthening by betatron motion along bending sections is explained. The formula describes a longitudinal and transverse coupling for a single-pass line, which is obtained as an extension of the formula for a storage ring. The bunch lengthening is expressed by a product of three factors: the square root of horizontal betatron emittance, a betatron phase factor, and the square root of the H-function, in other words, dispersion action. That effect had been calculated in many reports concerning with sub-ps electron bunch generation, such as the laser-bunch slicing, the vertical bunch deflection by a crab cavity, and the beam transport along a quasi-isochronous bending arcs. In these works the transfer matrix elements, R15 and R25, had been calculated for each of various conditions. On the contrary, our simple and general analytical formula gives a good foresight to understand the observed phenomena and for an easy optimization of parameters of bending arcs.

 
THPD090 Design of Modified Lattice of Long Straight Section in the SPring-8 Storage Ring 4497
 
  • K. Soutome, K. Fukami, M. Oishi, Y. Okayasu, J. Schimizu, Y. Shimosaki, M. Shoji, M. Takao, H. Yonehara
    JASRI/SPring-8, Hyogo-ken
 
 

A set of three in-vacuum undulators is going to be installed in one of four long straight sections of the SPring-8 storage ring. In order to make the undulator gap as narrow as possible, we plan to divide this long straight section into three sub-sections and install quadrupole magnets between these sub-sections to lower the vertical betatron function. In the modified lattice, however, the symmetry of the ring is lowered and in general it becomes difficult to keep a sufficient dynamic aperture for on- and off-momentum electrons. The long straight sections were originally introduced in the year 2000 and at that time we developed a method of "quasi-transparent matching of sextupole fields" where two key concepts of betatron phase matching and local chromaticity correction were combined to obtain a sufficient dynamic aperture and momentum acceptance. Then, in the year 2007 "counter-sextupole magnets" were further installed to cancel the effect due to non-linear kick by sextupole magnets used for local chromaticity correction. In designing the new lattice with a modified long straight section, we followed the same line and could recover the dynamic aperture and momentum acceptance.

 
THPD091 Explicit Maps for the Fringe Field of a Quadrupole 4500
 
  • D.M. Zhou
    KEK, Ibaraki
  • Y. Chen, J. Tang, N. Wang
    IHEP Beijing, Beijing
 
 

A perturbation method based on Lie technique, originated by J. Irwin and C.-x. Wang, was extended to calculate the linear maps for the fringe field of a quadrupole. In our method, the fringe field shape is not necessarily anti-symmetric with respect to the hard-edge position. The linear maps were explicitly expressed as functions of fringe field integrals. Thus they can be used to assess the influence of the quadrupole fringe fields in beam dynamics.

 
THPD092 Applications of Advanced scaling FFAG Accelerator 4503
 
  • J.-B. Lagrange, Y. Ishi, Y. Kuriyama, Y. Mori, K. Okabe, T. Planche, T. Uesugi, E. Yamakawa
    KURRI, Osaka
 
 

Until today, scaling FFAG accelerator were only designed in a ring shape. But a new criteria of the magnetic field configuration satisfying the scaling condition even for straight FFAG beam line has been recently found. Moreover, combining different types of cells can be used to imagine new lattices. Various applications using these recent developments are here examined: inprovements of the PRISM project and the ERIT project, and a zero-chromatic carbon gantry concept are presented.

 
THPD093 New Approaches to Muon Acceleration with Zero-chromatic FFAGS 4506
 
  • T. Planche, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, K. Okabe, T. Uesugi, E. Yamakawa
    KURRI, Osaka
 
 

The acceleration of intense muon beams up to 25 GeV is the challenge of the international design work for a future neutrino factory. The present baseline scenario for muon acceleration is based on linacs, recirculating linear accelerators (RLAs) and non-scaling fixed field alternating gradient (FFAG) rings. However RLAs are one of the most cost driving part. Two new approaches to use zero-chromatic FFAG instead of RLA have been proposed. Detailed lattices parameters and 6D tracking results are presented.

 
THPD094 Production of Femtosecond Electron Pulse using Alpha Magnet together with Off-crest Acceleration for Generation of Coherent THz Radiation 4509
 
  • F. Miyahara, H. Hama, F. Hinode, M. Kawai, T. Muto, K. Nanbu, H. Oohara, Y. Tanaka
    Tohoku University, School of Scinece, Sendai
 
 

We have studied production of the very short-bunch electron beam to generate intense coherent THz radiation*. The bunch length of 100 fs is required to produce CSR around 1 THz. The beam from the thermionic RF-gun is introduced into the bunch compression system consist of an alpha magnet and a linac. The alpha magnet is often used as a bunch compressor for electron energy of several MeV. However, for our system, the alpha magnet plays a role of the longitudinal phase space rotator and energy filter. The bunch compression is done in the linac employing velocity bunching. The beam is injected on near the zero-cross phase of the RF field in the linac, and then the beam phase slip toward the crest. The longitudinal phase space and beam phase with respect to RF field at the entrance of the linac are optimized so that the bunch length would be minimum. In current analysis using numerical simulation based on the GPT code**, an rms bunch length of 30 fs has been obtained for a bunch charge of 20 pC. We will discuss the bunch compression scheme and the beam dynamics in the system. Prospect of the coherent radiation from the beam will be also reported.


* H. Hama et al, Proc. Ultrashort Electron & Photon Beam Techniques and Applications, Xian, China (2009)
** General Particle Tracer (GPT), URL: http://www.pulsar.nl/gpt

 
THPD096 Simulation of Multiknobs Correction at ATF2 4512
 
  • S. Bai, J. Gao
    IHEP Beijing, Beijing
  • P. Bambade
    KEK, Ibaraki
  • B. Bolzon
    IN2P3-LAPP, Annecy-le-Vieux
 
 

The ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with a purpose to reach a 37nm vertical beam size at the interaction point. During initial commissioning, we started with larger than nominal β-functions at the IP, to reduce the effects from higher-order optical aberrations and thereby simplify the optical corrections needed. We report on simulation studies at two different IP locations developed based on waist scan, dispersion, coupling and β function multiknobs correction in the large β optics of ATF2, in the presence of two kinds of magnet inaccuracies (quadrupole gradient and roll errors) to generate all possible linear optics distortions at the IP. A vertical beam size which is very close to the nominal beam size is obtained based on the simulation study.