EPAC08 - List of Keywords (beam-transport)

A B C D E F G H I K L M N O P Q R S T U V W

beam-transport

Paper	Title	Other Keywords	Page
MOPC040	COBALD - an Inverse Compton Back-scattering Source at Daresbury	laser, electron, photon, vacuum	160
	D. J. Holder STFC/DL/ASTeC, Daresbury, Warrington, Cheshire D. Laundy STFC/DL, Daresbury, Warrington, Cheshire G. Priebe STFC/DL/SRD, Daresbury, Warrington, Cheshire
	An inverse Compton Back-scattering (CBS) ultra-short pulsed x-ray source driven by the multi-terawatt laser installed at Daresbury’s Energy Recovery Linac Prototype (ERLP) is being developed. Hard x-rays, ranging from 15 keV to 30 keV, depending on the backscattering geometry, will be generated through the interaction of the laser pulse and an electron bunch delivered by ERLP. The X-rays created contain 15 ·10⁶ photons per pulse from head-on collisions, with a pulse duration comparable to that of the incoming electron bunch, and 5 ·10⁶ photons per pulse from side-on collisions, where the laser pulse defines the pulse width. The peak spectral brightness of ≈10²⁰ photons/s/mm²/mrad²/0.1% ΔE/E is close to that of 4th-generation synchrotron light sources. Called COBALD, it will initially be used as a short pulse diagnostic for the ERLP electron beam and will explore the extreme challenges of photon/electron beam synchronization, which is a fundamental requirement for all accelerator-based (whether FEL or spontaneous SR) dynamics programmes. Furthermore, a fast-melting experiment will be used as a diagnostic tool to provide further information on the stability of the source.

MOPC059	BBU Limitations for ERLs	dipole, linac, recirculation, lattice	199
	E. Wooldridge, C. D. Beard, P. A. McIntosh, B. D. Muratori, S. L. Smith STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	The BBU threshold in ERLs is a limitation on the maximum beam current due to the interaction of the electron bunches and the Higher Order Modes (HOMs) contained within the RF cavities. Several factors are involved in determining the threshold current; from the cavity the Q, R/Q and degeneracy of the modes all play an important part. From the beam transport the values of the lattice functions α, β and μ have an effect. We will discuss the limits on these variables to provide a BBU current threshold greater than 100 mA for a multiple cavity machine and what will be required to provide higher currents. Also three different cavity profiles were investigated with the aim of reducing the BBU threshold. The TESLA 9-cell cavity was used as a baseline for comparison against possible 7-cell cavity designs, using the TESLA cell shape for their inner cells. The ends of the 7-cell cavities join to different sized beampipes, with radii of 39 mm and 54 mm, to allow the most of the HOMs to propagate to a broadband HOM absorber. Two different beampipe to cavity to transitions were investigated. The optimised 7-cell cavity will be shown to provide an increase in the BBU threshold.

MOPC150	Modifications to the Analysing Magnet in the ISIS Penning Ion Source	extraction, ion-source, ion, emittance	427
	S. R. Lawrie, D. C. Faircloth, A. P. Letchford, M. E. Westall, M. Whitehead, T. Wood STFC/RAL/ISIS, Chilton, Didcot, Oxon J. K. Pozimski STFC/RAL, Chilton, Didcot, Oxon
	A full 3D electromagnetic finite element analysis and particle tracking study is undertaken of the ISIS Penning surface plasma ion source using CST Particle Studio 2008. The existing 90° analysing magnet is found to have a magnetic field index of 1.3, causing beam divergence and contributing to beam loss. Different magnet pole piece geometries are modelled and the effect of space charge investigated. Based on this modelling, three new sets of poles are manufactured and tested on the Ion Source Development Rig. The results are presented herein.

MOPC155	Transport System for Ion Implantation	ion, ion-source, undulator, cathode	439
	S. M. Polozov, E. S. Masunov MEPhI, Moscow R. P. Kuibeda, T. Kulevoy, V. Pershin, S. Petrenko, D. N. Selesnev, I. M. Shamailov, A. L. Sitnikov ITEP, Moscow
	ITEP in collaboration with MEPHI and IHE (Tomsk) develops the high intensity ion beam generation and transport systems for low energy (1-50 keV) ion implantation. Such facilities are used for semiconductor technology. The Bernas type ion source is used for ribbon ion beam production. The periodical system of electrostatic lenses (electrostatical undulator) was proposed for ribbon beam transport line. The design of transport system and the results of beam dynamics investigation are presented. The influence of the electrodes construction errors on the beam dynamics is discussed.

TUZG01	IFMIF: Status and Developments	target, rfq, plasma, radio-frequency	974
	P. Garin CEA, Gif-sur-Yvette
	On the way to the fusion demonstrator (DEMO), ITER is designed to tackle the physics properties of thermonuclear plasmas in relevant conditions, as well as the key technologies. But because of its experimental character, the amount of neutrons produced by ITER all along its life will be about two orders of magnitude below what is expected in a fusion Power Plant. A dedicated facility, called IFMIF (International Fusion Materials Irradiation Facility), is thus mandatory to study and analyse the behaviour of materials under a high flux of energetic neutrons (14 MeV). The Engineering Validation and Engineering Design Activities (EVEDA), launched in the framework of a bilateral agreement between Euratom and the Government of Japan in 2007, with a duration of 6 years, aims at producing the detailed design file enabling the construction of IFMIF. The key systems will be also tested during this phase. One of the most important one is the accelerator, bringing a deuteron beam of 125 mA to an output energy of 40 MeV. The whole facility will be described, including the detail of the accelerator, as well as the organisational framework of the project.
	Slides

TUPC071	Computer-assisted Electron Beam Centroid Characterization at AIRIX Facility	diagnostics, electron, extraction, target	1212
	O. Mouton, M. Caron, D. Collignon, H. Dzitko, B. Gouin, G. Grandpierre, D. Guilhem, L. Hourdin, C. Noel, O. Pierret CEA, Bruyères-le-Châtel
	AIRIX is a high current accelerator designed for flash X-ray radiography. The electron beam produced into a vacuum diode (2 kA, 3.5 to 3.8 MV, 60 ns) is extracted from a velvet cold cathode. For a beam characterisation we have seen* how to calculate the mean beam divergence (X'(0),Y'(0)), the RMS beam size (XRMS(0), YRMS(0)) as well as the 2D transverse beam emittance (ex(0),ey(0)). To have a complete initial characterization of the beam, we have to further calculate the centroid initial position (xc, yc) and its initial divergence (xc', yc'). In this aim, we use experimental results at BPM's located downstream the initial position of the cathode, and we also use the TRAJENV code coupled with the MINUIT minimization library. In this paper, we propose to describe both experimental and theoretical approaches leading to the full beam characterization (beam size, centroid position and divergence) at the diode output. *O. Mouton & al. "Computer assisted Electron Beam Characterization at AIRIX Facility," PAC'07, Albuquerque (USA).

TUPC092	An Application for Beam Profile Reconstruction with Multi-wire Profile Monitors at J-PARC RCS	injection, linac, controls, synchrotron	1272
	H. Sako, S. Hiroki, K. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken H. Ikeda Visual Information Center, Inc., Ibaraki-ken H. Takahashi JAEA, Ibaraki-ken
	J-PARC RCS is commissioned since October 2007. In the early stage of RCS commissioning, Multi-Wire Profile Monitors (MWPM's) are most important beam monitors to measure positions and profiles of beam orbit in the injection line from LINAC. A MWPM consists of either a horizontal or a vertical wire plane. Each wire plane consists of several wires which has a tilt angle, and a wire scatters H^- or proton beams and induced current in the wire is detected. A wire plane moves at a small step in the perpendicular direction to the wires and scans a beam profile. A complex analysis procedure and geometrical description is developed to reconstruct a beam profile from a MWPM. Beam profiles have been measured at MWPM's in the injection line and the H0 beam dump line.

TUPD037	Design and Development of Intercepting Devices at the Spallation Neutron Source	radiation, vacuum, linac, diagnostics	1508
	R. T. Roseberry, S. Assadi, D. W. Crisp, K. R. Gawne ORNL, Oak Ridge, Tennessee
	Beam measurements in the LINAC and transport lines of the Spallation Neutron Source at Oak Ridge National Laboratory utilize a variety of intercepting instruments such as in-line emittance systems, wire scanners, scrapers and scintillation view screens. All of these devices require linear actuators with vacuum feedthroughs. The majority of the actuators acquired during the construction phase of the SNS were of commercial origin and have proven unable to meet long-term physics and engineering requirements. The predominant difficulties with these devices were lack of precision, reliability and longevity. Three new families of linear actuators have been developed at the SNS to address these deficiencies. The approach used in their development, has been to utilize a combination of commercially available linear motion components in custom built chassis to address the needs of a given set of applications. This approach has yielded devices that have met or exceeded expectations for accuracy, precision, radiation resistance, longevity and economy. Aspects of the underlying design of these actuators and their implementation will be presented at this conference.

TUPP085	Beam Dynamics Using Graphical Processing Units (GPUs)	lattice, extraction, simulation, collimation	1727
	R. Appleby, D. Bailey, M. D. Salt UMAN, Manchester
	Simulation of particle beam dynamics in accelerators is computationally expensive, and requires very high particle statistics and accuracy. Conventional beam tracking tools operate sequentially on particle phase space to compute the trajectories of particles through many turns of circular, and linear, machines. Graphical Processing Units (GPUs) utilise stream processing techniques to dramatically speed up parallel computational tasks, and offer considerable performance benefits to particle beam dynamics processing. In this paper, the stream processing beam dynamics code GPMAD is presented, which exploits the NVidia GPU processor, and demonstrates the considerable performance benefits to particle tracking calculations. The accuracy and speed of GPMAD is benchmarked using the Diamond Light Source BTS lattice, and the collimation system is evaluated.

TUPP100	A Four-dimensional Vlasov Solver for Microbunching Instability in the Injection System for X-ray FELs	simulation, collective-effects, electron, emittance	1764
	M. Migliorati, A. Schiavi Rome University La Sapienza, Roma G. Dattoli ENEA C. R. Frascati, Frascati (Roma) M. Venturini LBNL, Berkeley, California
	The phenomenon of microbunching instabilty arises from small charge-density fluctuations in the electron bunches that are amplified by the combined effect of space charge and coherent synchrotron radiation as the beam travels through magnetic compressors. In order to study the coupled longitudinal and transverse beam dynamics we propose to develop a four-dimensional grid-based Vlasov solver. The goal is to give an accurate characterization of the microbunching instability seeded by the random noise present in the initial bunch distribution. Solving directly the Vlasov equation instead of using macroparticle simulations has the advantage of avoiding the statistical fluctuations due to a limited number of macroparticles. Because a Vlasov solver in a high dimension phase-space tends to be particularly time consuming, to be practical a code implementing this method should run on parallel processors. In this paper we report progress toward the realization of such a 4D Vlasov solver.

TUPP102	Beam Transport with Scattering Using SRIM Supporting Software Routines Code	scattering, emittance, simulation, ion	1767
	M. Pavlovic, I. Strasik STU, Bratislava
	In many situations a particle beam is transported through matter-containing components separated by ion-optical elements. The matter-containing components scatter the beam and alter its emittance diagram. In order to include accurately the scattering in beam-transport a special beam-transport module was included in the SRIM Supporting Software Modules package (S3M). It uses transfer-matrix formalism in ion-optical elements. At the entry to a scattering element a beam-generation routine converts the actual σ-matrix into an ensemble of particles and writes a special SRIM input-file. The beam-transport in the scattering element is then calculated by SRIM MC particle tracking. At the exit of the scattering element, the module imports back the SRIM output data and can either continue with transfer-matrix transformations or generate a modified σ-matrix that can be used by other ion-optical programs. It means the beam transport with scattering can either be fully calculated by S3M, or data exchange between S3M and ion-optical programs can be provided. S3M beam-transport module is described in the paper with some typical application examples. M. Pavlovic, I. Strasik. Supporting Routines for the SRIM code, Nucl. Instr. and Meth. B 257 (2007) 601-604.

TUPP134	Commissioning of the Carbon Beam Gantry at the Heidelberg Ion Therapy (HIT) Accelerator	ion, proton, synchrotron, quadrupole	1842
	U. Weinrich, C. M. Kleffner GSI, Darmstadt
	The HIT facility comprises the only carbon ion gantry worldwide. This gantry is especially unique in offering fully flexible beam transport to the patient for carbon ions up to an energy of 430 MeV/u. It includes a full 3D-beam scanning system and full medical treatment environment. The gantry can be rotated by 360 degree so that the beam may be directed at the patient from arbitrary directions. Commissioning with beam of the gantry was successfully started in January 2008 when the first proton and carbons beams were transported into the gantry treatment room. Based on theoretical calculations for rotation independent settings of the beam optics, the beam commissioning aims for an efficient practical way to realize the full variety of required beam properties (2 ion types, 10 intensities, 255 energy steps, and four beam sizes) in the isocenter independent of the gantry angle. The presentation will report on the concept and progress of the beam commissioning process.

WEPP053	Beam Transport in Toroidal Magnetic field	injection, simulation, proton, ion	2641
	N. S. Joshi, M. Droba, O. Meusel, U. Ratzinger IAP, Frankfurt am Main
	The concept of a storage ring with toroidal magnetic field was presented in the two previous EPAC conferences. Here we report the first results of experiments performed with beam transport in toroidal magnetic fields and details of the injection system. The beam transport experiments were carried out with 30 degree toroidal segments with an axial magnetic field of 0.6T. The space charge force and dynamics of a proton beam near the brillouin flow limit are presented here. The multiturn injection system relies on a specified injection coil together with an electric kicker system. The scaling law for the complete storage ring is discussed. The advantages and disadvantages for such a stellarator type storage ring on the 5T level will be reviewed.

THXG01	SNS Progress, Challenges and Upgrade Options	linac, target, injection, beam-losses	2892
	S. Henderson ORNL, Oak Ridge, Tennessee
	The talk describes the progress of SNS towards 1 MW, includes discussion of the challenges of successfully running high power superconducting pulsed proton linacs, and also looks forward to upgrade programmes.
	Slides

THPPGM03	EPS-AG 2008 Gersh Budker Prize Presentation: The Successful Construction and Commissioning of the Spallation Neutron Source	target, linac, proton, site	2960
	N. R. Holtkamp ITER, St Paul lez Durance N. R. Holtkamp ORNL, Oak Ridge, Tennessee
	The Spallation Neutron Source collaboration between six Department of Energy laboratories was a unique arrangement in its mission to build a large science facility, with equally distributed responsibility for design, construction, project management and budget. The Oak Ridge National Laboratory, with no previous experience in large accelerator construction, was selected as the project site, the team was recruited worldwide, and the management team was exchanged several times during the construction period. The constraints of such a collaboration, a new team having to work together on a complex project, facing demanding scientific and technical challenges, is a cocktail that can easily lead to failure, but also to success, as proven. Was it luck or good management that decided the fate of the project? Can the weakness of such a situation simultaneously become its strength? In hindsight, it is interesting to reflect on how it was done and what became of some of the key players. Certainly this experience in many ways provided the author with a key to face a much larger challenge, namely the management of an international science project shared between seven Countries, called ITER. A project that takes the concepts tried at SNS to another extreme. Comparisons will be provided and some of the unique features will be discussed.
	Slides

THPC028	High Energy Beam Transport Line for the IFMIF-EVEDA Accelerator	quadrupole, diagnostics, emittance, dipole	3041
	C. Oliver, B. Brañas, A. Ibarra, I. Podadera Aliseda CIEMAT, Madrid N. Chauvin, A. Mosnier, D. Uriot CEA, Gif-sur-Yvette
	The IFMIF-EVEDA accelerator will be a 9 MeV, 125 mA cw deuteron accelerator which will verify the validity of the design of the future IFMIF accelerator. A transport line is necessary to handle the high current beam from the DTL exit up to the beam dump. This line must produce the beam expansion to obtain an acceptable power density at the beam dump. Therefore the design of the transport line must consider the geometry and power handling capacity of the beam dump, the space requirements for diagnostics and the restrictions on the maximum length of the line. In addition, a bending magnet is required in order to avoid excessive irradiation of the diagnostics and line elements by neutrons and gammas produced at the beam dump and to perform energy spread measurements. In this contribution, the preliminary design of the high energy beam transport line will be presented. The results of a sensitivity study to the input beam and line elements errors will also be discussed.

THPC054	Transportation of Decay Products in the Beta-beam Decay Ring	dipole, ion, lattice, quadrupole	3104
	A. Chancé, J. Payet CEA, Gif-sur-Yvette
	The principle of the neutrino production in the beta-beams relies on the beta-decay of the radioactive ions Neon 18 and Helium 6 in a storage ring. After decaying, the daughter particles have their magnetic rigidity significantly changed (-33% for Helium and +11% for Neon). Therefore, the decay products will be quickly lost on the walls of the decay ring after entering a dipole. Absorbers have been inserted in the decay ring in order to collect most decay products. Their optimization implies to calculate the trajectories of the decay products in the dipoles for very large momentum differences with a good accuracy. For pure dipoles without fringe field as in the decay ring, an analytic treatment can be used to simulate the transportation. It is then possible to obtain the equivalent dipole which gives the beam sizes of the daughter particles. In a first part, we will describe the analytic treatment of the central trajectory and the motion of the ions around. In a second part, we will compare this treatment with the one with matrices for different orders in the case of the beta-beam decay ring.

THPP044	Experience with the SNS SC Linac	linac, beam-losses, emittance, focusing	3461
	Y. Zhang, A. V. Aleksandrov, C. K. Allen, I. E. Campisi, S. M. Cousineau, V. V. Danilov, J. Galambos, J. A. Holmes, D.-O. Jeon, S.-H. Kim, T. A. Pelaia, A. P. Shishlo ORNL, Oak Ridge, Tennessee
	The SNS SC linac (SCL) is designed to deliver 1 GeV, up to 1.56 MW pulsed H^- beams for neutron production. Beam commissioning of the SNS accelerator systems completed in June 2006 with the maximum linac output beam energy approximately 952 MeV. In 2007, we successfully tuned the SCL for 1 GeV beams during a test run, and the SNS linac achieved its design energy for the first time. During the linac tune-up, phase scan signature matching, drifting beam measurement as well as linac RF cavity phase scaling was applied. In this paper, we will introduce the experiences with the SCL, and we will also briefly discuss beam parameter measurements.

THPP052	Electron Cooling Force Calculations for HESR	electron, ion, plasma, antiproton	3482
	K. Rathsman, B. Gålnander, D. Reistad TSL, Uppsala H. Danared MSL, Stockholm
	The High energy storage ring HESR at FAIR is being realized by a consortium consisting of Forschungszentrum Jülich, GSI Darmstadt and Uppsala University. An important feature of this new facility is the combination of phase-space cooled beams and dense internal targets. Charmonium spectroscopy, which is one of the main items in the experimental program, requires antiproton momentum up to 8.9 GeV/c with a resolution of dp/p=0.00001. This can only be achived with electron cooling. The electron cooler proposed for HESR allows beam cooling between 1.5 GeV/c and 8.9 GeV/c. Along the 24 m interaction section beween electrons and antiprotons, the electrons are guided by a solenoid field of 0.2 T with a field straightness of 0.00001 radians rms. To predict the final momentum resolution of the antiproton beam in HESR, electron cooling force calculations, simulations of electron cooling and comparison to experimental data are needed. This paper focuses on the force calculations. The method is based on the theory by Derbenev and Skrinsky, (i.e. the Vlasov techique) and the electron cooling force is numerically calulated using adaptive Monte Carlo integration methods.

THPP074	Optimal Design of a High Current MEBT with Chopper	kicker, emittance, target, focusing	3533
	A. V. Aleksandrov ORNL, Oak Ridge, Tennessee
	Many existing and proposed projects require a certain temporal structure imposed on the beam pulse, e.g., creating gaps for low-loss extraction from a circular accelerator. Usually it is achieved using chopper systems. In order to reduce average beam power on the target and simplify kicker requirements chopper system is located in a lower energy part of the accelerator, typically in the medium energy transport line (MEBT) between the RFQ and the linac. Many of the MEBT layouts, proposed and in use, look very much alike and try to achieve a compromise between two opposing requirements of providing strong transverse focusing and sufficiently long empty drifts for the kickers. As a result, both requirements are not fully satisfied leading to space charge induced emittance increase and very challenging technical specifications for the kicker and its power supply. These difficulties quickly increase with the beam current. We propose a different MEBT layout, which does not compromise quality of beam transport and allows space for a kicker with any reasonable parameters. A generic design of a 5.5m long MEBT transporting 100mA with emittance increase of less than 5% is shown as an example.

THPP079	Design of the High Current Linac of SPES Project	linac, rfq, target, klystron	3545
	A. Pisent, M. Comunian, E. Fagotti, A. Palmieri, P. A. Posocco INFN/LNL, Legnaro, Padova F. Grespan Università degli Studi di Milano, Milano
	The proposed driver, composed by a four vanes RFQ and an Alvarez DTL, generates a high intensity beam, for an average current of 1.5 mA and an energy of 43 MeV, upgradable to 95 MeV. The high rep rate (50 Hz) is necessary for the correct mechanical behavior of the target. The accelerator is composed by the source TRIPS, built at LNS and now in operation at LNL, by the RFQ of TRASCO research program (5 MeV 30 mA), very advanced in the construction, and by a normal conducting Drift Tube Linac (DTL). This last accelerating structure is the same proposed for LINAC4 at CERN. A prototype of this structure, of interest for both projects, is in construction in Italy with the joint effort of CERN and LNL. The RFQ and the two tanks of the DTL are fed by 3 klystrons; the first one, with a power of 1.3 MW, is already at LNL, while the other two with a power of 2.5 MW each are the same adopted for LINAC4. The power supply of the RF system (50 Hz 0.6 ms) has been evaluated in details on the bases of the system in operation for the Japanese project JPARC. This paper illustrates the physical design and beam dynamics studies of this linac.

THPP104	The High Energy Beam Transport System for FAIR	extraction, diagnostics, dipole, ion	3608
	S. Ratschow, F. Hagenbuck, P. J. Spiller GSI, Darmstadt
	The High Energy Beam Transport System of FAIR, with a total length of more than 2350 m, forms a complex system connecting seven accelerator- and storage-rings, the experimental caves, beam dumps, stripping stations, the antiproton target and the Super-FRS. The variety of beams to be transported is considerable, ranging from slow extracted beams with long spills of up to 100 s to short intense bunches with lengths of a few nanoseconds and a momentum spread of up to ±1%. The range of beam intensity covers more than six orders of magnitude. The SIS100/300 rings are located 13.5 m under ground while the rest of the facility is essentially on ground level necessitating a 3-dimensional layout of the beam line system. Most of the beam transport system consists of normal conducting magnets. However, the SIS300 beam line system has to be built with superconducting magnets. Due to the large variety of beam parameters, a careful planning of the beam diagnostics system is important. The paper summarizes the design fundamentals and the current status of the system design.