LINAC 2004 - List of Keywords

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

rfq

Paper	Title	Other Keywords	Page
MO301	SPIRAL2 at GANIL	ion, linac, emittance, ion-source	23
	M.-H. Moscatello GANIL, Caen
	The detailed design study phase of the SPIRAL2 project has been launched since beginning of 2003. The aim of this facility is to produce rare ion beams, using a Uranium carbide target fission process, based on a fission rate of 10¹³ to 10¹⁴ fissions/s. The driver accelerator accelerates a 5 mA deuteron beam up to 20 MeV/u, impinging on a carbon converter to produce the neutrons necessary to the fission process. It has also to accelerate q/A=1/3 heavy ions, to energies between 0.75 and 14.5 MeV/A for different types of nuclear and non-nuclear physics experiments. The accelerator, based on a RFQ followed by an independently phased superconducting cavity linac with warm focusing sections, is under design. This paper presents the reference design chosen for SPIRAL2 driver accelerator and gives the design status of the different components: Sources, RFQ, Superconducting linac, RF Systems, Cryogenics, Mechanical layout.
	Transparencies

MOP03	Proposal for Reduction of Transverse Emittance of BNL 200 MeV Linac	emittance, linac, injection, proton	36
	J. Alessi, J. Beebe Wang, D. Raparia, W.-T. Weng BNL, Upton, Long Island, New York
	BNL plans to upgrade the AGS proton beam from the current 0.14 MW to higher than 1.0 MW and beyond for such a neutrino facility which consists of two major subsystems. First is a 1.2 GeV super-conducting linac (SCL) to replace the booster as injector for the AGS. Second is the performance upgrade for the AGS itself for the higher intensity and repetition rate. For high intensity proton accelerators, such as the upgraded AGS, there are very stringent limitations on uncontrolled beam losses. A direct effect of linac beam emittance is the halo/tail generation in the circulating beam. Studies show the estimated halo/tail generation in the beam for present normalized RMS emittance of linac beam is unacceptable. To reduce the transverse emittance of 200 MeV linac, the existing radio frequency quadrupole linac (RFQ) has to be relocated closer to drift tube linac (DTL) tank 1 to meet emittance requirement for the AGS injection with low loss. This paper will present the various options of matching between RFQ and DTL, and chopping options in the low energy beam transport (LEBT).

MOP05	The HITRAP-Decelerator for Heavy Highly-Charged Ions	ion, extraction, emittance, storage-ring	39
	L. Dahl, W. Barth, T. Beier, W. Vinzenz GSI, Darmstadt C. A. Kitegi, U. Ratzinger, A. Schempp IAP, Frankfurt-am-Main
	The GSI accelerator facility provides highly charged ions up to U⁹²⁺ by stripping the ions at 400 MeV/u in the transfer line from the SIS18 (Heavy Ion Synchrotron) to the ESR (Experimental Storage Ring). The ESR provides high quality beams by means of stochastic cooling and electron cooling. Deceleration down to 4 MeV/u was already successfully demonstrated. After suitable rebunching, further deceleration down to 6 keV/u, neccessary for the capture of the ions by a penning trap, is done by IH/RFQ-structures. All cavities are operated at 108 MHz. Recently the HITRAP-project (Heavy Ion Trap), described in a Technical Design Report, was approved. The layout of the decelerator and the beam dynamics in different sections are reported.

MOP06	A Dedicated 70 MeV Proton Linac for the Antiproton Physics Program of the Future Facility for Antiproton and Ion Research (FAIR) at Darmstadt	proton, linac, ion, antiproton	42
	L. Groening, W. Barth, L. Dahl, R. Hollinger, P. Spädtke, W. Vinzenz, S. Yaramishev GSI, Darmstadt B. Hofmann, Z. Li, U. Ratzinger, A. Schempp, R. Tiede IAP, Frankfurt-am-Main
	The antiproton physics program of the future International Accelerator Facility at Darmstadt is based on a rate of 7·10¹⁰ cooled antiprotons per hour. To provide the primary proton intensities a proton linac is planned, which will be operated independently from the existing UNILAC for heavy ions. The proposed linac comprises a proton source, a RFQ, and a DTL. Its operation frequency of 352 MHz allows for an efficient acceleration to up to 70 MeV using normal conducting Crossed-bar H-cavities. These CH-cavities show high shunt impedances as known from IH-structures, but allow for much higher relative particle velocities of up to 40%. The beam pulses with a length of 25 μs, a current of 70 mA, and total transverse emittances of 7 μm will allow to fill the existing synchrotron SIS within one multi-turn-injection up to its space charge limit of 7·10¹² protons. The maximum SIS ramping rate limits the applied proton linac repetition rate to 5 Hz. This paper gives an overview of the proposed proton linac. The status of the design including beam dynamic studies will be reported.
	Transparencies

MOP09	Status of the 7 MeV/u, 217 MHz Injector Linac for the Heidelberg Cancer Therapy Facility	ion, linac, quadrupole, ion-source	51
	B. Schlitt, K. Dermati, G. Hutter, F. Klos, C. Mühle, W. Vinzenz, C. Will, O. Zurkan GSI, Darmstadt A. Bechtold, U. Ratzinger, A. Schempp IAP, Frankfurt-am-Main Y.R. Lu PKU/IHIP, Beijing
	A clinical synchrotron facility for cancer therapy using energetic proton and ion beams (C, He and O) is under construction and will be installed at the Radiologische Universitätsklinik in Heidelberg, Germany, starting in 2005. The status of the ECR ion source systems, the beam line components of the low energy beam transport lines, the 400 keV/u RFQ and the 20 MV IH-cavity as well as the linac rf system will be reported. Two prototype magnets of the linac quadrupole magnets have been built at GSI and have been tested successfully. A test bench for the 1.4 MW, 217 MHz cavity amplifier built by industry has been installed at GSI including a 120 kW driver amplifier which will be used also for high power tests of the RFQ. A test bench for the RFQ using proton beams is presently being set up at the IAP. RF tuning of the 1:2 scaled IH-DTL model as well as Microwave Studio simulations of the model and the power cavity have been also performed at the IAP [1]. [1] Y.Lu, S.Minaev, U.Ratzinger, B.Schlitt, R.Tiede, this conference.
	Transparencies

MOP10	The IH Cavity for HITRAP	emittance, ion, bunching, simulation	54
	C. A. Kitegi, U. Ratzinger IAP, Frankfurt-am-Main S. Minaev ITEP, Moscow
	RFQs are already successfully used to decelerate ions and to match them to ion traps. Within the Heavy Ions TRAP project HITRAP at GSI a combination of an IH drift tube cavity operating at the H11(0) mode and a 4-rod RFQ is proposed to decelerate the 1 ms long heavy ion bunches (up to U⁹²⁺) from 4 A×MeV to 6 A keV after storage ring extraction. The transition energy from the IH into the RFQ is 0.5AmeV. The operating frequency is 108.408 MHz. The A/q range of the linac is up to 3.A 4-gap quarter wave resonator working at 108.408MHz provides theμbunch structure for the IH. The transmission mainly defined by the buncher is about 30%. An alternative 2nd harmonic bunching section, which allows higher transmission and/or smaller longitudinal emittance, will be discussed.By applying the KONUS dynamics, the 2.7 meter long IH cavity will perform a high efficient deceleration by up 10.5 MV with 200kW rf power. The beam dynamics performed with the LORASR simulation code will be shown. It is aimed to reach an effective shunt impedance around 220MW/m for the IH cavity

MOP11	The Compact 20 MV IH-DTL for the Heidelberg Cancer Therapy Facility	simulation, ion, linac, emittance	57
	Y.R. Lu, Y.R. Lu, B. Schlitt GSI, Darmstadt S. Minaev ITEP, Moscow U. Ratzinger, R. Tiede IAP, Frankfurt-am-Main
	A clinical synchrotron facility for cancer therapy using energetic proton and ion beams (C, He and O) is under construction and will be installed at the Radiologische Universitätsklinik in Heidelberg, Germany, starting in 2005. The different rf tuning concepts and tuning results for an 1:2 scaled IH-DTL model cavity are presented. Microwave Studio simulations have been carried out for the model and for the real power cavity. Results from the model measurements and the field simulations agree very well also for the higher order modes. The beam matching from the RFQ to the IH-DTL was optimised. Beam dynamics simulations using the LORASR code and starting with a particle distribution at the RFQ exit as calculated with PARMTEQ are presented. The IH drift tube array was matched with the gap voltage distribution resulting from rf model measurements.

MOP12	KONUS Beam Dynamics Design of a 70 mA, 70 MeV Proton CH-DTL for GSI-SIS12	linac, proton, acceleration, quadrupole	60
	R. Tiede, G. Clemente, H. Podlech, U. Ratzinger IAP, Frankfurt-am-Main W. Barth, L. Groening GSI, Darmstadt Z. Li IMP, Lanzhou S. Minaev ITEP, Moscow
	The future scientific program at GSI needs a dedicated proton injector into the synchrotron SIS, in order to increase the proton intensity of the existing UNILAC/SIS12 combination by a factor of 70, resulting in 7· 10¹² protons in the synchrotron. A compact and efficient 352 MHz RFQ - CH-DTL combination based on novel structure developments for RFQ and DTL was worked out. For DTLs operated in an H-mode like CH-cavities (H210-mode), the shunt impedance is optimized by use of the KONUS beam dynamics. Beam dynamics simulation results of the CH-DTL section, covering the energy range from 3 to 70 MeV, with emphasis on the low energy front end are presented. Optimization aims are the reduction of emittance growth, of beam losses and of capital costs, by making use of the high acceleration gradients and shunt impedance values provided by the Crossbar H-Type (CH) structure. In addition, the beam dynamics design of the overall DTL layout has to be matched to the power limits of the available 352 MHz power klystrons. The aim is to power each cavity by one klystron with a peak rf power of around 1 MW.

MOP14	Development of Intense Beam Proton Linac in China	linac, proton, dipole, vacuum	63
	S. Fu, S.X. Fang, H. Ouyang, S. Zhao IHEP Beijing, Beijing B. Cui, X. Guan CIAE, Beijing J. Fang, Z.Y. Guo PKU/IHIP, Beijing
	Study on intense beam proton linac was started about four years ago in a national program for the basic research on ADS in China. This ADS program is meant for the future development of the clean nuclear power generation. Another important application of HPPA for Chinese Spallation Neutron Source was also proposed recently in China, and it is financially supported by Chinese Academy of Sciences. In this paper, the research progress on intense beam proton linac in these two application fields will be outlined. It involves the test result of an high-current ECR proton source, construction status of a 3.5 MeV RFQ accelerator and the design of a DTL linac.

MOP15	TRASCO-RFQ as Injector for the SPES-1 Project	target, linac, focusing, beam-losses	66
	P. Posocco, M. Comunian, A. Pisent INFN/LNL, Legnaro, Padova E. Fagotti INFN Milano, Milano
	The funded first phase of SPES foresees the realization at LNL of a facility able, on one hand, to accelerate a 10 mA protons beam up to 20 MeV for nuclear studies and, on the other hand, to accelerate a 30 mA protons beam up to 5 MeV for BNCT and preliminary ADS studies. In this two-way facility, the TRASCO RFQ will operate in two different current regimes. Moreover a specific MEBT has to be designed able to match the beam to the following superconducting linac and to deliver a beam with the correct characteristics to the neutron production target for the BNCT studies.

MOP16	The TRASCO-SPES RFQ	vacuum, dipole, quadrupole, coupling	69
	A. Pisent, M. Comunian, J. Esposito, A. Palmieri INFN/LNL, Legnaro, Padova E. Fagotti INFN Milano, Milano G. Lamanna CINEL, Vigonza (PD) M. S. Mathot CERN, Geneva
	A high intensity RFQ is under construction at LNL. Developed within TRASCO research program, the Italian feasibility study an ADS (Accelerator Driven System), it will be employed as the first accelerating element of SPES facility, the ISOL project of LNL. The RFQ operates at the frequency of 352 MHz in CW mode, is able to deliver a proton current up to 30 mA and consists of six brazed segments whose length is 1.2 m. In this article the results obtained from the construction of a 20 cm “technological model”, aimed at testing the construction procedure of the final structure, will be discussed. Finally we will report about the machining and the outcomes obtained after RF testing of the first two segments built up to now.

MOP17	Design of the SPES-1 LEBT	electron, simulation, ion, proton	72
	E. Fagotti INFN Milano, Milano M. Comunian, A. Pisent INFN/LNL, Legnaro, Padova
	The low-energy-beam transport (LEBT) system for the SPES-1 accelerator transports the beam at 80 keV and 30 mA from the ion-source TRIPS to the TRASCO RFQ entrance. A second mode of operation corresponding to 10 mA current is also foreseen. The code PARMELA performed these simulations of the beam transport through the LEBT. This code is used to transport H⁺ and H²⁺ in the electrostatic fields of the ion-source extraction, in the magnetic fields of both the source and the solenoid lenses and under space charge and neutralization influence.

MOP19	Particle Distributions at the Exit of the J-PARC RFQ	simulation, linac, beam-transport, injection	78
	Y. Kondo, A. Ueno JAERI, Ibaraki-ken K. Ikegami, M. Ikegami KEK, Ibaraki
	A 324 MHz, 3 MeV RFQ (Radio-Frequency Quadrupole) linac with 3.115 m vane length is used as the first RF linac of the J-PARC linac. The results of the J-PARC linac end-to-end (from the RFQ entrance to the injection point of the RCS) simulations significantly depend on the initial particle distributions. In the transverse phase spaces, Gaussian particle distributions, whose parameters were decided to reproduce the emittance measured in the LEBT (Low Energy Beam Transport), was used at the entrance of the RFQ. Two simulation codes, PARMTEQM and TOUTATIS, were used to produce the particle distributions at the exit of the RFQ. Since the simulated emittances showed good agreements with the emittances measured at downstream of the RFQ, they were confirmed to have the validity to be used as the initial distribution of the end-to-end simulation.

MOP71	Advanced Beam-Dynamics Simulation Tools for RIA	linac, simulation, beam-losses, acceleration	186
	T.P. Wangler, R. Garnett LANL, Los Alamos, New Mexico N. Aseev, P.N. Ostroumov ANL/Phys, Argonne, Illinois R. Crandall TechSource, Santa Fe, NM D. Gorelov, R.C. York NSCL, East Lansing, Michigan J. Qiang, R. Ryne LBNL, Berkeley, California
	Understanding beam losses is important for the high-intensity RIA driver linac. Small fractional beam losses can produce radioactivation of the beamline components that can prevent or hinder hands-on maintenance, reducing facility availability. Operational and alignment errors in the RIA driver linac can lead to beam losses caused by irreversible beam-emittance growth and halo formation. We are developing multiparticle beam-dynamics simulation codes for RIA driver-linac simulations extending from the low-energy beam transport (LEBT) line to the end of the linac. These codes run on the NERSC parallel supercomputing platforms at LBNL, which allow us to run simulations with large numbers of macroparticles for the beam-loss calculations. The codes have the physics capabilities needed for RIA, including transport and acceleration of multiple-charge-state beams, and beam-line elements such as high-voltage platforms within the linac, interdigital accelerating structures, charge-stripper foils, and capabilities for handling the effects of machine errors and other off-normal conditions. We will present the status of the work, including examples showing some initial beam-dynamics simulations.

TU101	Engineering and Building RF Structures - The Works	vacuum, linac, simulation, radio-frequency	237
	D. Schrage LANL, Los Alamos, New Mexico
	The translation of the physics designs of linear accelerators into engineering and manufacturing requirements is discussed. The stages of conceptual design, prototyping, final design, construction, and installation are described for both superconducting (LANL β = 0.175 Spoke Cavity) and normal-conducting (APT/LEDA 6.7 MeV RFQ) accelerators. An overview of codes which have linked accelerator cavity and thermal/structural analysis modules is provided.
	Transparencies

TU103	Development of the UNILAC Towards a Megawatt Beam Injector	ion, heavy-ion, linac, proton	246
	W. Barth, L. Dahl, J. Glatz, L. Groening, S. Richter, S. Yaramishev GSI, Darmstadt
	For the future Facility for Antiproton and Ion Research (FAIR) at Darmstadt the present GSI-accelerator complex, consisting of the linear accelerator UNILAC and the heavy ion synchrotron SIS18, is foreseen to serve as an U²⁸⁺ injector for up to 10¹² particles/sec. After a new High Current Injector was installed, many different ion species were accelerated in the UNILAC for physics experiments. In 2001 a high energy physics experiment used up to 2·10⁹ uranium ions per spill (U⁷³⁺), while a MEVVA ion source was in routine operation for the first time. In the past two years different hardware measures and a careful fine tuning in all sections of the UNILAC resulted in an increase of the beam intensity to 9.5·10¹⁰ U²⁷⁺ ions per 100 μs or 1.5·10¹⁰ U⁷³⁺ ions per 100 μs. The contribution reports results of beam measurements during the high current operation with uranium beams (pulse beam power up to 0.5 MW). One of the major tasks was to optimize the beam matching to the Alvarez-DTL. In addition further upgrades, including improved beam diagnostics, are described, which allow to fill the SIS18 up to the space charge limit of 2.7·10¹¹ U²⁸⁺ ions per cycle.
	Transparencies

TUP01	RFQ Drift-Tube Proton Linacs in IHEP	focusing, linac, quadrupole, emittance	285
	Yu. Budanov, O.K. Belyaev, S.V. Ivanov, A.P. Maltsev, I.G. Maltsev, V.B. Stepanov, S.A. Strekalovskyh, V.A. Teplyakov, V. Zenin IHEP Protvino, Protvino, Moscow Region
	A linac with drift tubes and RF quadrupoles (alias, an RFQ DTL) constitutes a natural extension of the RFQ concept towards higher beam energies. Complementing an RFQ with drift tubes intermitted by spacer electrodes separates functions of focusing and acceleration. Such a structure allows for an increased accelerating rate and upgrades shunt impedance to values competitive against those inherent in the other common accelerator types. Various accelerating/focusing structures for the RFQ DTLs were implemented in IHEP. Their succession is marked by a progress in performance, which is due to efforts in design, manufacturing technology and calculation technique advances that facilitated R&D of such the structures. A sound practical expertise in the field is accumulated. The 30 MeV RFQ DTL is in service as an injector for a 1.5 GeV PS of IHEP since 1985. An upgraded successor – the RFQ DTL, employing a cavity loaded by a novel accelerating/focusing structure with an increased accelerating rate, is now being assembled and tested. Its pre-commissioning results will be outlined. Prospects in R&D of a structure suitable for a front-end part of the CERN SPL will be evaluated.
	Transparencies

TUP03	Design of the LINAC4, A New Injector for the CERN Booster	linac, proton, injection, quadrupole	291
	M. Vretenar, R. Garoby, K. Hanke, A.M. Lombardi, C. Rossi CERN, Geneva F. Gerigk CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
	A new H^- linac (LINAC4) is presently under study at CERN. This accelerator, based on normal conducting structures at 352 and 704 MHz, will provide a 40 mA 160MeV H^- beam to the CERN booster, thus overcoming the present space-charge bottleneck at injection with a 50 MeV proton beam. LINAC4 is conceived as the first stage of a future 2.2 GeV superconducting linac (SPL) and it is therefore designed for a higher duty cycle than required for injection in the booster. This paper discusses the design choices, presents the layout of the facility and illustrates the advantages for the LHC and other CERN users. An R&D and construction strategy mainly relying upon international collaborations is also presented.

TUP04	The SPL Front End: A 3 MeV H^- Test Stand at CERN	linac, proton, quadrupole, simulation	294
	R. Garoby, L. Bruno, F. Caspers, J. Genest, K. Hanke, M. Hori, D. Kuchler, A.M. Lombardi, M. Magistris, A. Millich, M. Paoluzzi, C. Rossi, E.Zh. Sargsyan, M. Silari, T. Steiner, M. Vretenar CERN, Geneva P.-Y. Beauvais CEA/DSM/DAPNIA, Gif-sur-Yvette
	In the frame of the SPL (Superconducting Proton Linac) study at CERN, a new 160 MeV proton injector for the CERN PS Booster is presently under development. This linear accelerator (Linac4) would not only be a first step towards a future, multi-MW superconducting linac, but would also improve in the medium term both the beam availability and beam quality for CERN’s proton users. Within the framework of the Linac 4 study and with the support of the EU funded Joint Research Activity HIPPI, a 3 MeV test stand is under construction at CERN. This test stand will explore some of the most critical issues of the linac, such as the beam dynamics at low energy, with special emphasis on the Chopper line that has been designed to generate the required time structure of the beam, to clean the beam halo, and to match it to the subsequent RF structures. In this context, a new Beam Shape and Halo Monitor is under construction. The beam acceleration will be performed by an RFQ that is being developed in France within the IPHI collaboration between CEA and CNRS. Moreover, the test stand will be equipped with an additional 1 MW RF klystron to test different RF structures that are being designed at 352 MHz as preliminary studies for the Linac4. High Intensity Pulsed Proton Injectors
	Transparencies

TUP05	Beam Dynamics for a new 160 MeV H^- Linac at CERN (LINAC4)	linac, emittance, quadrupole, simulation	297
	F. Gerigk CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon E. Benedico Mora, A.M. Lombardi, E.Zh. Sargsyan, M. Vretenar CERN, Geneva
	LINAC4 is a normal conducting H^- linac proposed at CERN to provide a higher proton flux to the CERN accelerator chain. It should replace the existing LINAC2 as injector for the PS booster. The same machine can also operate in the future as the front end of the SPL, a 2.2 GeV superconducting linac with 1.8 mA average current. At present the test set-up for LINAC4 consists of a Radio Frequency Quadrupole (RFQ), a chopper line, a Drift Tube Linac (DTL), and Cell Coupled DTL (CCDTL) operating at 352.2 MHz and finally a Side Coupled Linac (SCL) at 702.2 MHz. This paper discusses the overall beam dynamics concept, presents the optics for the different sections of the machine and compares end-to-end simulations realised with two tracking codes (PATH and IMPACT). Estimates of beam loss due to various error sources are presented and the challenging features in the current design are highlighted.
	Transparencies

TUP06	Results of the High-Power Conditioning and the First Beam Acceleration of the DTL-1 for J-PARC	coupling, linac, acceleration, quadrupole	300
	F. Naito, S. Anami, J. Chiba, Y. Fukui, K. Furukawa, Z. Igarashi, K. Ikegami, M. Ikegami, E. Kadokura, N. Kamikubota, T. Kato, M. Kawamura, H. Kobayashi, C. Kubota, E. Takasaki, H. Tanaka, S. Yamaguchi, K. Yoshino KEK, Ibaraki K. Hasegawa, Y. Kondo, A. Ueno JAERI, Ibaraki-ken T. Itou, Y. Yamazaki JAERI/LINAC, Ibaraki-ken T. Kobayashi J-PARC, Ibaraki-ken
	The first tank of the DTL for Japan Proton Accelerator Research Complex (J-PARC) was installed in the test facility at KEK. The DTL tank is 9.9 m in length and consists of the 76 cells. The resonant frequency of the tank is 324 MHz. After the installation of the tank, the high-power conditioning was carried out deliberately. Consequently the peak rf power of 1.3 MW (pulse repetition 50 Hz, pulse length 600 μs) was put into the tank stably. (The required power is about 1.1 MW for the designed accelerating field of 2.5 MV/m on the axis.) Following the conditioning, negative hydrogen beam, accelerated by the RFQ linac up to 3 MeV, was injected to the DTL and accelerated up to its design value of 19.7 MeV. The peak current of 30 mA was achieved with almost 100% transmission. In this paper, the conditioning history of the DTL and the result of the first beam test will be described.

TUP08	Carbon Ion Injector Linac for a Heavy Ion Medical Synchrotron	linac, ion, focusing, vacuum	306
	D.A. Swenson LLC, Albuquerque, New Mexico
	The design of a Carbon Ion Injector Linac for a heavy ion medical synchrotron will be presented. The linac is designed to accelerate quadruply-ionized carbon ions (¹²C⁴⁺) with a charge/mass ratio (q/A) of 0.333, and all other ions with the same or higher charge/mass ratios, such as H¹⁺, H₂¹⁺, D¹⁺, T¹⁺, ³He¹⁺, ⁴He²⁺, ⁶Li²⁺, ¹⁰B⁴⁺, and ¹⁶O⁶⁺ to an output energy of 7 MeV/u. The 200 MHz linac consists of an Radio Frequency Quadrupole (RFQ) linac to accelerate the ions from an input energy of 0.008 MeV/u to an intermediate energy of 0.800 MeV/u, and an Rf-Focused Interdigital (RFI) linac to accelerate these ions to the output energy. The combined linac structures have a total length of 7.8 meters and a total peak rf power requirement of about 600 kW. The RFQ linac employs a radial-strut, four-bar design that is about twice as efficient as the conventional four-bar RFQ design. The RFI linac, which is basically an interdigital drift tube structure with rf quadrupole focusing incorporated into each drift tube, is about 5 times more efficient than the conventional Drift Tube Linac (DTL) structure. Details of the linac structures and their calculated performance will be presented.

TUP09	The Heidelberg High Current Injector: A Versatile Injector for Storage Ring Experiments	ion, ion-source, storage-ring, extraction	309
	R. von Hahn, M. Grieser, R. Repnow, D. Schwalm, C.P. Welsch MPI-K, Heidelberg
	The High Current Injector (HCI) was designed and built as a dedicated injector for the Test Storage Ring in Heidelberg to deliver mainly singly charged Li- and Be-ions. After start for routine operation in 1999 the HCI delivered stable beams during the following years for about 50 % of the experiments with very high reliability. Due to the requirements from the experiment the HCI changed during that period from a machine for singly charged positive ions to an injector for a large variety of molecules as well as positively or negatively charged light ions. After successful commissioning of the custom built 18 GHz high power ECR-source at its present test location various modifications and additions were made in preparation of a possible conversion into an injector for highly charged heavy ions as a second phase. This paper gives an overview of the experience gained in the passed 5 years and presents the status of the upgrade of the HCI.

TUP10	Design of a Deuteron RFQ for Neutron Generation	ion, ion-source, proton, target	312
	Z.Y. Guo, J. Chen, J. Fang, Y.R. Lu, S.X. Peng, Z.Z. Song, J.X. Yu, C. Zhang, K. Zhu PKU/IHIP, Beijing A. Schempp IAP, Frankfurt-am-Main
	A deuteron RFQ is designed for neutron generation with 9Be(d,n)10B reaction. Considering the limitation of available RF transmitter, the frequency was chosen as 201.5 MHz and the peak RF power was set to 400 kW with 10% duty factor. The deuteron beam will be extracted from an ECR ion source also with 10% duty factor and then be accelerated to about 2 MeV by RFQ with high transmission efficiency. The system will be described and the design results of particle dynamics and structure will be given.

TUP11	High current RFQ using laser ion source	laser, plasma, ion, ion-source	315
	M. Okamura, R.A. Jameson, J. Takano, K. Yamamoto RIKEN, Saitama R. Becker, A. Schempp IAP, Frankfurt-am-Main T. Fujimoto AEC, Chiba T. Hattori, N. Hayashizaki TIT, Tokyo Y. Iwata, S. Shibuya NIRS, Chiba-shi H. Kashiwagi JAERI/ARTC, Gunma-ken
	A new RFQ was fabricated for very high current heavy ions. The designed target current is 100 mA with cabon 4⁺ beam. Acceleration test result will be reported at the conference.

TUP14	Status of the RFI Linac Prototype	linac, ion, ion-source, quadrupole	321
	D.A. Swenson, W.J. Starling LLC, Albuquerque, New Mexico
	A prototype of the Rf Focused Interdigital (RFI) linac structure is currently under construction at Linac Systems. The RFI linac structure is basically an interdigital (or Wideröe) linac structure with rf quadrupole focusing incorporated into each drift tube. The 200 MHz RFI prototype, consisting of a short RFQ linac followed by a short RFI linac, will accelerate a 20 mA beam of protons from an injection energy of 25 keV to an output energy of 2.50 MeV in a total linac structure length of 1.44 meters. The linac structures are designed for continuous (cw) operation, and will be tested initially at a 33% duty factor. The peak structure power of 66 kW and peak beam power of 50 kW will be supplied by a 144 kW, 33% duty rf power system. A microwave ion source will supply the proton beam and an articulated Einzel lens will steer and focus the beam into the RFQ aperture. The mechanical design of the linac structures will be presented, the calculated performance will be described, the status of the components will be reported. The prototype is scheduled to come into operation in the fall of this year.

TUP16	Investigation on Beam Dynamics Design of High-Intensity RFQs	focusing, space-charge, acceleration, emittance	327
	C. Zhang, A. Schempp IAP, Frankfurt-am-Main J. Chen, J. Fang, Z.Y. Guo PKU/IHIP, Beijing
	Recently various potential uses of high-intensity beams bring new opportunities as well as challenges to RFQ accelerator research because of the new problems arising from the strong space-charge effects. Unconventional concepts of beam dynamics design, which surround the choice of basic parameters and the optimization of main dynamics parameters’ variation along the machine, are illustrated by the designing Peking University (PKU) Deuteron RFQ. An efficient tool of LANL RFQ Design Codes for beam dynamics simulation and analysis, RFQBAT, is introduced. Some quality criterions are also presented for evaluating design results.

TUP18	Beam Dynamics Issues of SPES-1 Linac	linac, quadrupole, simulation, emittance	330
	E. Fagotti INFN Milano, Milano M. Comunian, A. Palmieri, A. Pisent INFN/LNL, Legnaro, Padova
	An Independent Superconducting Cavity Linac able to accelerate 10 mA CW proton beam up to 20 MeV has been studied for the SPES-1 project. This paper presents the results of beam dynamics studies through SPES linac including mapped fields effects on cavities and magnets.

TUP19	Characterization of Beam Parameter and Halo for a High Intensity RFQ Output under Different Current Regimes	emittance, simulation, space-charge, proton	333
	E. Fagotti INFN Milano, Milano M. Comunian, A. Palmieri, A. Pisent INFN/LNL, Legnaro, Padova
	The characterization of the beam distribution at the exit of a high intensity RFQ is a crucial point in view of a correct simulation of beam behavior in the following linac structure. At this scope we need to know the beam halo quantification as a function of the input beam and RFQ parameters. In this paper, the description of Beam halo based upon moments of the particle distribution at the exit of the TRASCO-RFQ is given.

TUP21	Beam Dynamics Design of J-PARC Linac High Energy Section	linac, injection, simulation, beam-transport	339
	M. Ikegami, T. Kato, S. Noguchi KEK, Ibaraki H. Ao, Y. Yamazaki JAERI/LINAC, Ibaraki-ken K. Hasegawa, T. Ohkawa, A. Ueno JAERI, Ibaraki-ken N. Hayashizaki TIT, Tokyo V.V. Paramonov RAS/INR, Moscow
	J-PARC linac consists of a 3 MeV RFQ linac, a 50 MeV DTL (Drift Tube Linac), a 190 MeV SDTL (Separate-type DTL), and a 400 MeV ACS (Annular-Coupled Structure) linac. Recently, the beam dynamics design of the ACS part has been slightly modified to reduce construction cost. Namely, the number of klystron modules are reduced from 23 to 21, and the number of accelerating cells in one klystron module is increased from 30 to 34 to maintain the total energy gain. This design change curtails the margin for RF power by around 5 %, and the total length of the ACS section is nearly unchanged. The beam matching section between SDTL and ACS is also revised correspondingly. These modifications of the design are described in this paper together with 3D particle simulation results for the new design.

TUP27	Acceleration of Several Charge States of Lead Ion in CERN LINAC3	linac, ion, acceleration, injection	351
	V. Coco, J.A. Chamings, A.M. Lombardi, E.Zh. Sargsyan, R. Scrivens CERN, Geneva
	CERN’s LINAC3 is designed to accelerate a 100 μAe Pb²⁵⁺ ion beam from 2.5 keV/u to 4.2 MeV/u. The beam is then stripped using a carbon foil and the resulting 25 μAe 54⁺ beam is accumulated and cooled in the Low Energy Ion Ring (LEIR) before transfer to the Proton Synchrotron (PS) and ultimately to the Large Hadron Collider (LHC). The Pb²⁵⁺ ions are selected with a spectrometer from a mixture of ten charge states produced by an Electron Cyclotron Resonance (ECR) source. In view of the fact that the stripping efficiency to Pb⁵⁴⁺ is mostly dependent on energy and not on initial charge state, the feasibility of simultaneously accelerating to 4.2 MeV/u several charge states has been investigated. In this paper we report two possible technical solutions, their advantage in terms of intensity for the downstream machines and the experimental results supporting these conclusions.

TUP66	An Alternate Scheme for J-PARC SDTL Tuning	emittance, simulation, injection, linac	417
	M. Ikegami KEK, Ibaraki Y. Kondo, A. Ueno JAERI, Ibaraki-ken
	J-PARC linac consists of a 3 MeV RFQ linac, a 50 MeV DTL (Drift Tube Linac), a 190 MeV SDTL (Separate-type DTL), and a 400 MeV ACS (Annular-Coupled Structure) linac. As presented in a separate paper, we plan to perform phase-scan with precise TOF (Time Of Flight) beam-energy measurement in RF tuning of SDTL tanks. As a back-up method, we are considering to prepare an RF tuning scheme with rough TOF measurement for SDTL. In this paper, the principle of this scheme is presented, and its advantages and disadvantages are discussed based on a systematic particle simulation.

TUP82	Low Energy Beam Transport using Space Charge Lenses	space-charge, ion, emittance, focusing	465
	O. Meusel, A. Bechtold, H. Klein, J. Pozimski, U. Ratzinger, A. Schempp IAP, Frankfurt-am-Main
	Gabor lenses provide strong cylinder symmetric electric focusing using a confined nonneutral plasma. The density distribution of the enclosed space charge is defined by the enclosure conditions in transverse and longitudinal direction. For a homogeneous charge density distribution the resulting electrostatic field and therefrom the focusing forces inside the space charge cloud are linear. Additionally in case of a positive ion beam the space charge of the confined electrons causes compensation of the ion beam space charge forces. To study the capabilities of a Gabor double lens system to match an ion beam into a RFQ a testinjector was installed at the IAP and put into operation successfully. First beam profiles and emittance measurements as well as measurements of the beam energy and energy spread have already been performed and show satisfactory results and no significant deviation from the theoretical predictions. To verify the beam focusing of bunched beams using this lens type at beam energies up to 500 keV a new high field Gabor lens was build and will be installed behind of the RFQ.

TUP93	Results of a 3D-EM-Code Comparison on the TRISPAL Cavity Benchmark	coupling, simulation, resonance	495
	P. Balleyguier CEA/DAM, Bruyères-le-Châtel
	Several 3D electromagnetic codes (MAFIA, CST MicroWave-Studio, Vector-Fields Soprano, Ansoft HFSS, SLAC Omega3P) have been tested on a 2-cell cavity benchmark. Computed frequencies and Q-factors were compared to experimental values measured on a mock-up, putting the emphasis on the effect of coupling slots. It comes out that MAFIA limitations due to the staircase approximation is overcome by all other codes, but some differences still remain for losses calculations in re-entrant corners

WE201	Results from the Initial Operations of the SNS Front End and Drift Tube Linac	emittance, linac, ion-source, ion	533
	V. Aleksandrov ORNL/SNS, Oak Ridge, Tennessee
	The Spallation Neutron Source accelerator systems will deliver a 1 GeV, 1.44 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of an H^- injector (the Front-End), capable of producing one millisecond long pulses with 38 mA of peak current at a repetition rate of 60 Hz, a 1 GeV linear accelerator, an accumulator ring and associated transport lines. A 2.5 MeV beam from the injector is accelerated to 86 MeV in the Drift Tube Linac, then to 185 MeV in a Coupled-Cavity Linac and finally to 1 GeV in a Superconducting Linac. The staged beam commissioning of the accelerator is proceeding in parallel with component installation. The Front End and Drift Tube Linac tanks 1-3 have been commissioned at ORNL. The primary design goals of peak current, transverse emittance and beam energy have been achieved. Beam with 38 mA peak current, 1 msec beam pulse length, and 1 mA average beam current has been accelerated through the DTL tank 1. Results and status of the beam commissioning program will be presented. * on behalf of the SNS Project
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WE202	Recent Results in the Field of High Intensity CW Linac Development for RIB Production	linac, target, proton, ion	538
	A. Pisent INFN/LNL, Legnaro, Padova
	High Intensity CW Linacs have been proposed as driver accelerators for RIB production in various projects, since thy can drive in steady conditions a MW power range target for the production of spallation neutrons that induce fission in a natural uranium target. Particularly important for this application, with a relatively low beam current, is the necessity to develop a superconducting intermediate energy part with good power conversion efficiency. The second specific requirement of RIB facility drivers, that is also fulfilled by a superconducting intermediate energy linac, is the necessity to keep some flexibility in the species that can be accelerated (deuterons or light ions). In EURISOL RTD project a 1 GeV 5 mA proton linac, has been proposed for this application. In SPES project, recently approved for its initial phase at LNL, a lower energy proton beam will be used on a solid target. The results of the specific R&D programs on in the field of CW RFQ and superconducting low energy linacs will be illustrated. In particular for LNL the status of the RFQ construction and the superconducting cavities prototype tests will be given.
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TH101	Status of the J-PARC Linac, Initial Results and Upgrade Plan	linac, emittance, ion, proton	554
	Y. Yamazaki JAERI/LINAC, Ibaraki-ken
	The J-PARC linac building will be completed by March, 2005, when the installation of the linac components will start. On the other hand, the front end linac, comprising the 3 MeV RFQ linac, the MEBT with the beam chopper, and the 20 MeV DTL first tank, is under beam commissioning in the KEK site. A peak current of 30 mA, which is enough for the 0.6 MW operation of Rapid-Cycling Synchrotron (RCS), was accelerated up to 20 MeV on the second day of the beam commissioning, last November. The detailed study of the system is under way, including the stability test of many components. The front end linac will be shipped to the JAERI Tokai site after the building completion there. The beam commissioning of the 181 MeV linac will start in September 2006, that of the 3 GeV RCS in May, 2007, and that of the 50 GeV Main Synchrotron (MR) in November 2007. The beam acceleration in the MR will be done by March, 2008. It is strongly recommended by the government committee that the upgrade to the 400 MeV linac should start immediately after the completion of the above accelerator system, that is, in April 2008, with the period of three years, aiming the 1 MeV RCS beam power.
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TH102	Overview of High Intensity Linac Programs in Europe	linac, proton, ion, target	559
	M. Vretenar, R. Garoby CERN, Geneva
	Recent years have seen a boost in the European Union (EU) engagement for accelerator research in Europe. Laboratories and institutions from member states are invited to combine their efforts and to define common goals and strategies, in order to receive a financial support up to 50% of the total project cost. In the field of High Intensity Linacs, the EU had already supported the EURISOL initiative for nuclear physics, which this year is applying for funding of a Design Study, and the development of linacs for Waste Transmutation. More recently, an initiative for high-energy physics has been approved, which includes a programme for the development of pulsed linac technologies. Together with the ongoing national projects, these European initiatives represent a strong focussed effort towards the development of linac technologies, intended to overcome difficulties coming from decreasing national budgets. This paper presents a summary of the requests coming from the European physics communities and an overview of linac R&D activities sponsored by the EU, together with some information on parallel national projects. The parameter choices as well as the main technical features of the different projects are presented and compared.
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THP03	DESIGN IMPROVEMENT OF THE RIA 80.5 MHZ RFQ	ion, emittance, linac, simulation	599
	Q. Zhao, V. Andreev, M. Doleans, D. Gorelov, T.L. Grimm, W. Hartung, F. Marti, S.O. Schriber, X. Wu, R.C. York NSCL, East Lansing, Michigan
	An 80.5 MHz, continuous-wave, normal-conducting, radio-frequency quadrupole (RFQ) was designed for the front end of the Rare Isotope Accelerator (RIA) driver linac. It will accelerate various ion beams (hydrogen up to uranium) from 12 keV/u to about 300 keV/u. The 4-meter-long RFQ accepts the pre-bunched beam from the low energy beam transport (LEBT) and captures more than 80% with a current of ~0.3 mA. Beam dynamics simulations show that the longitudinal output emittance is small for both single^- and two-charge-state ion beams with an external multi-harmonic buncher. A 4-vane resonator with magnetic coupling windows was employed in the cavity design to provide large mode separation, high shunt impedance, and a small transverse dimension. The results of beam dynamics as well as the electromagnetic simulations are presented.

THP08	The Frankfurt Funneling Experiment	ion, linac, emittance, simulation	614
	A. Schempp, U. Bartz, N. Müller, J. Thibus, H. Zimmermann IAP, Frankfurt-am-Main
	Funneling is a procedure to multiply beam currents of rf-accelerators at low energies. In the ideal case the beam current can be multiplied in several stages without emittance growth. The Frankfurt Funneling Experiment consists of two ion sources, a Two-Beam RFQ accelerator, two different funneling deflectors and a beam diagnostic equipment system. The whole set-up is scaled for He⁺ instead of Bi⁺ for the first funneling stage of a HIIF driver. The progress of our experiment and the results of the simulations will be presented.

THP10	Tuner Design for High Power 4-Rod-RFQs	linac, simulation, ion, vacuum	617
	A. Schempp, L. Brendel, B. Hofmann, H. Liebermann IAP, Frankfurt-am-Main
	The performance of high power RFQ linacs, as used in spallations sources and proposed for projects like ADxy, IFMIF or high duty factor drivers for RIB application are limited by beam dynamics properties as well as technical limits like sparking, power density, cooling and thermal stresses. A "one piece structure" even possible in theory has to have means for tuning the real fields like exchangable or moving tuners. Tuner design features will be discussed and results will be presented.

THP11	Design of A 352 MHz-Proton-RFQ for GSI	proton, emittance, antiproton, linac	620
	A. Schempp, L. Brendel, B. Hofmann IAP, Frankfurt-am-Main
	Part of the future project of GSI is a new p-linac for the production of Antiprotons. The 4- Rod-RFQ operating at 350 MHz has to accelerate up to 100 mA protons from an ECR source. Design studies have been made using the Parmteq- and Microwave Studio codes to optimize beam dynamics properties and the field distribution of the RFQ. Results of the design studies will be presented.

THP12	Superconducting RFQs in the PIAVE Injector	feedback, linac, cryogenics, target	623
	G. Bisoffi, G. Bassato, G. Bezzon, A. Calore, S. Canella, F. Chiurlotto, A. Lombardi, P. Modanese, A.M. Porcellato, S. Stark INFN/LNL, Legnaro, Padova
	The PIAVE superconducting RFQs were installed on the linac line and connected to the TCF50 cryogenic system. First results on the on-line resonator performance (e.g. Q-curves, amplitude and phase locking) are described as well as the behaviour of the fast tuners.

THP47	The RF-System for A High Current RFQ at IHEP	klystron, cathode, power-supply, monitoring	712
	Z. Zhang, J. Li, J. Qiao, X. Xu IHEP Beijing, Beijing
	The R&D of a high current proton RFQ is one of the most important research tasks of the Accelerator Driven Sub-critical system (ADS) basic research project. In preliminary research phase, the 352.2 MHz RF system will be operated in pulse mode. CERN kindly provided IHEP with some RF equipment. Because the given RF system was used for CW operation at CERN before, to apply them to our pulse mode operation, some modifications and improvements are necessary. We made some indispensable assemblies, and also did some tests and commissioning of every sub-system. At present, the initial high power conditioning of the klystron is finished, and output power can reach nominal value. A description of RF power system is given, in particularly, the performance of HV power supply, thyratron crowbar and capacitors, hard tube modulator and its control electronics, and klystron power conditioning are presented.
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THP52	RF Reference Distribution System for the J-PARC Linac	linac, klystron, power-supply, feedback	727
	T. Kobayashi, E. Chishiro JAERI, Ibaraki-ken S. Anami, S. Michizono, S. Yamaguchi KEK, Ibaraki
	J-PARC (Japan Proton Accelerator Complex) linac, which is 300 m long, consists of 324 MHz accelerating section of the upstream and 972 MHz section (as future plan) of the downstream. In the klystron gallery, totally about 50 RF source control stations will stand for the klystrons and solid-state amplifiers. The error of the accelerating field must be within ±1° in phase and ±1% in amplitude. Thus, the high phase stability is required to the RF reference for all of the low-level RF control systems and the beam monitor systems. This paper presents a final design of the RF reference distribution system for this linac. The RF reference (12 MHz) is distributed to all stations optically. Low-jitter E/O and O/E with temperature stabilizers are developed. The reference is optically amplified and divided into 14 transmission lines, and is delivered through PSOF (the phase-stabilized optical fiber), the temperature of which is stabilized by cooling water. Each of the transmitted signals is divided more into 4 signals by an optical coupler. Our objective for the phase stability of the reference aims at <±0.3° at a 972 MHz frequency.

THP54	Moscow Meson Factory DTL RF System Upgrade	vacuum, coupling, dipole, impedance	733
	A.I. Kvasha RAS/INR, Moscow
	The last paper devoted to description of the first part (DTL) RF system of Moscow Meson Factory upgrade was published in the Proceedings of PAC95 Conference in Dallas. Since then some new works directed at improvement of reliability and efficiency of the RF system were carried out. Among them there are a new powerful pulse triode “Katran” installed in the output RF power amplifiers (PA) of three channels, modifications of the anode modulator control circuit and crow-bar system, a new additional RF channel for RF supply of RFQ and some alterations in placing of the anode modulator equipment decreasing a level of interference’s at crow-bar circuits. Some new checked at MMF RF channels ideas concerning of PA tuning are of interest for people working in this sphere of activity.

THP86	Low Power Measurements on a Finger Drift Tube Linac	linac, simulation, ion, booster	800
	A. Schempp, K.-U. Kühnel IAP, Frankfurt-am-Main C.P. Welsch MPI-K, Heidelberg
	The efficiency of RFQs decreases at higher particle energies. The DTL structures used in this energy regions have a defocusing influence on the beam. To achieve a focusing effect, fingers with quadrupole symmetry were added to the drift tubes. Driven by the same power supply as the drift tubes, the fingers do not need an additional power source or feedthrough. Beam dynamics have been studied with PARMTEQ . Detailed analysis of the field distribution was done and the geometry of the finger array has been optimized with respect to beam dynamics. A spiral loaded cavity with finger drift tubes was built up and low power measurements were done. In this contribution, the results of the rf simulating with Microwave Studio are shown in comparison with bead pertubation measurement on a prototype cavity.

THP88	Longitudinal Bunch Shape Monitor Using the Beam Chopper of the J-PARC	linac, emittance, proton, beam-transport	806
	F. Naito KEK, Ibaraki
	We propose the longitudinal bunch shape monitor for the low energy part of the linac of the J-PARC. The monitor uses the beam chopper cavity installled in the MEBT line between thr RFQ and the DTL of the J-PARC as a kind of the bunch rotator. Consequentry the longitudinal bunch shape is measured along the horizontal direction. If we can measure the energy distribution of the bunch also, the longitudinal emittance of the beam is derived. In the paper, the basic idea of the monitor is discussed in detail.

FR103	Status of the SNS Linac: An Overview	linac, target, laser, proton	837
	N. Holtkamp ORNL, Oak Ridge
	The Spallation Neutron Source SNS is a second generation pulsed neutron source and under construction at Oak Ridge National Laboratory. The SNS is funded by the U.S. Department of Energy?s Office of Basic energy Sciences and is dedicated to the study of the structure and dynamics of materials by neutron scattering. A collaboration composed of six national laboratories (ANL, BNL, TJNAF, LANL, LBNL, ORNL) is responsible for the design and construction of the various subsystems. With the official start in October 1998, the operation of the facility will begin in 2006 and deliver a 1.0 GeV, 1.4 MW proton beam with a pulse length of approximately 700 nanoseconds on a liquid mercury target. The multi-lab collaboration allowed access to a large variety of expertise in order to enhance the delivered beam power by almost an order of magnitude compared to existing neutron facilities. The SNS linac consists of a combination of room temperature and superconducting structures and will be the first pulsed high power sc linac in the world. The challenges and the achievements will be described in the paper. SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos and Oak Ridge.
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