LINAC 2004 - Classification:Accelerators and Facilities/Ion Linacs

Accelerators and Facilities

Ion Linacs

Paper	Title	Page
MO302	Development of Room Temperature and Superconducting CH-Structures	28
	H. Podlech IAP, Frankfurt-am-Main
	H-mode cavities (IH-DTL, IH-RFQ, 4-Vane-RFQ) have been developed and operated successfully during the last decades for a large variety of applications in ion acceleration. At the IAP Frankfurt a new type of H-mode cavity, the CH-structure is under development. This multi cell drift tube cavity is operated in the H21 mode. Due to its mechanical stability, room temperature as well as superconducting cavities can be realized. The CH-structure is an excellent candidate for high power ion accelerators in the energy range from 5 to 100 MeV. The design status of the GSI 70 MeV, 70 mA proton injector DTL consisting of room temperature CH-structures is reported. Superconducting CH-structures can be used especially for cw operated linacs as designed for XADS, IFMIF or in nuclear physics projects. By using the KONUS beam dynamics and performing the particle simulations with the LORASR code it is possible to realize multi cell cavities without internal focusing lenses. A superconducting 352 MHz CH-structure (β=0.1) with 19 gaps has been built. We present the results of the first tests with this new cavity. The status of a PC version of the LORASR code will be reported.
	Transparencies
MOP01	Beam Intensity Adjustment in the RIA Driver Linac	33
	P.N. Ostroumov, J.A. Nolen, I. Sharamentov ANL/Phys, Argonne, Illinois A.V. Novikov-Borodin RAS/INR, Moscow
	The Rare Isotope Accelerator Facility currently being designed in the U.S. will use both heavy ion and light ion beams to produce radionuclides via the fragmentation and spallation reactions, respectively. Driver beam power of up to 400 kW will be available so that beam sharing between target stations is a viable option to increase the number of simultaneous users. Using a combination of rf-sweepers and DC magnets the driver beams can be delivered to up to four targets simultaneously. With simultaneous beam delivery to more than one target independent adjustment of the relative beam intensities is essential. To enable such intensity adjustment we propose to use a fast chopper in the Medium Energy Beam Transport (MEBT) section. Several options of fast chopper design are discussed. The MEBT beam optics is being designed to accommodate and match the chopper technical specifications. Possible solutions and performance with the fast chopper are proposed.
MOP03	Proposal for Reduction of Transverse Emittance of BNL 200 MeV Linac	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	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	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
MOP07	High Current Beam Transport to SIS18	45
	S. Richter, W. Barth, L. Dahl, J. Glatz, L. Groening, S. Yaramishev GSI, Darmstadt
	The optimized transversal and longitudinal matching of space charged dominated ion beams to SIS18 is essential for a loss free injection. This paper focuses on the beam dynamics in the transfer line (TK) from the post-stripper accelerator to the SIS18. Transverse beam emittance measurements at different positions along the TK were done. Especially, the different foil stripping modes were investigated. A longitudinal emittance measurement set-up was commissioned at the entry to the TK. It is used extensively to tune all the rebunchers along the UNILAC. An addition, a test bench is in use for measurements of longitudinal bunch profiles, which enables to monitor for the final debunching to SIS18. Multi particle simulations by means of PARMILA allow a detailed analysis of experimental results for different ion currents.
MOP08	Investigation of the Beam Matching to the GSI-Alvarez DTL under Space Charge Conditions	48
	S. Yaramishev, W. Barth, L. Dahl, L. Groening, S. Richter GSI, Darmstadt
	The UNILAC consists of the 36 MHz high current RFQ/IH-injector, a gas stripper section at an energy of 1.4 MeV/u and a 108 MHz Alvarez poststripper, accelerating all ions up to of 11.4 MeV/u. The design beam current for U²⁸⁺ is 12.6 emA at full energy. After the stripping process the electrical beam current is increased by a factor of 7 for uranium. This leads to a significant beam emittance growth during the transport through the charge state separator and the matching section to the Alvarez DTL. The paper reports results of beam experiments focused on the matching of the high intensity beams to the Alvarez for different ion species. Measured data are compared with the results of beam dynamics simulations. Possible improvements of the transverse focusing in the Alvarez linac are discussed and the total impact to the beam quality at the synchrotron injection is evaluated.
	Transparencies
MOP09	Status of the 7 MeV/u, 217 MHz Injector Linac for the Heidelberg Cancer Therapy Facility	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	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	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	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	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	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	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	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.
MOP18	Cold-Model Tests and Fabrication Status for J-PARC ACS	75
	H. Ao, H. Akikawa JAERI/LINAC, Ibaraki-ken K. Hasegawa, A. Ueno JAERI, Ibaraki-ken N. Hayashizaki TIT, Tokyo M. Ikegami, S. Noguchi KEK, Ibaraki V.V. Paramonov RAS/INR, Moscow Y. Yamazaki J-PARC, Ibaraki-ken
	The J-PARC (Japan Proton Accelerator Research Complex) LINAC will be commissioned with energy of 181-MeV using 50 keV ion source, 3 MeV RFQ, 50 MeV DTL and 181 MeV SDTL (Separated DTL) on September 2006. It is planed to be upgraded by using 400 MeV ACS (Annular Coupled Structure), which is a high-beta structure most suitable for the J-PARC, in a few years from the commissioning. The first ACS cavity, which will be used as the first buncher between the SDTL and the ACS, is under fabrication. Detailed design and tuning procedure of ACS cavities has been studied with RF simulation analysis and cold-model measurements. The results of cold-model measurements, fabrication status, and related development items are described in this paper.
MOP19	Particle Distributions at the Exit of the J-PARC RFQ	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.
MOP20	Design of the R.T. CH-Cavity and Perspectives for a New GSI Proton Linac	81
	Z. Li IMP, Lanzhou W. Barth, K. Dermati, L. Groening GSI, Darmstadt G. Clemente, H. Podlech, U. Ratzinger, R. Tiede IAP, Frankfurt-am-Main
	The CH-Structure has been studied at the IAP Frankfurt and at GSI for several years. Compared with the IH structure (H110-mode), the CH structure (H210-mode) can work at higher frequency (700 MHz) and can accelerate ions to higher energy (up to 150 AMeV). Detailed Microwave Studio (MWS) simulations were performed for this structure. Since a multi-gap cavity can be approximated as a quasi-periodic structure, it is possible to analyze one βλ/2-cell at an energy corresponding to the cavity center. Additionally, a reduced copper conductivity of 85% was assumed. Geometry variations with respect to rf frequency and shunt impedance can be performed rapidly by that method in the first stage of optimization. Effective shunt impedances from 100 MΩ/m down to 25 MΩ/m were obtained for the energy range from 5 AMeV to 150 AMeV by this method. The rf frequency was 350 MHz up to 70 MeV and 700 MHz above. A systematic analysis of the influence of the cell number in long CH cavities on the effective shunt impedance is presented. The possibility to apply this structure to a 70 mA, 70 MeV, 352 MHz proton linac for GSI is discussed.
TU103	Development of the UNILAC Towards a Megawatt Beam Injector	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
TU301	High Power CW Superconducting Linacs for EURISOL and XADS	275
	J.-L. Biarrotte IPN, Orsay
	A multi-MW superconducting proton linac is proposed as the baseline solution for the EURISOL and the XADS driver accelerators. In the EURISOL project, which studies the design of the next-generation European ISOL facility, it is used to produce both neutron-deficient and neutron-rich exotic nuclei far from the valley of stability. In the PDS-XADS project, which aims to the demonstration of the feasibility of an ADS system for nuclear waste transmutation, it is used to produce the neutron flux required by the associated sub-critical reactor. In this paper, we report the main results and conclusions reached within these preliminary design studies. A special emphasis is given on the on-going and future R&D to be done to accomplish the demonstration of the full technology.
	Transparencies
TUP01	RFQ Drift-Tube Proton Linacs in IHEP	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
TUP02	Development of a 352 MHz Cell-Coupled Drift Tube Linac Prototype	288
	M. Vretenar, Y. Cuvet, J. Genest, C. Völlinger CERN, Geneva F. Gerigk CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
	At linac energies above 40 MeV, alternative structures to the conventional Drift Tube Linac can be used to increase efficiency and to simplify construction and alignment. In the frame of the R&D activities for the CERN SPL and Linac4, a prototype of Cell-Coupled Drift Tube Linac (CCDTL) at 352 MHz has been designed and built. This particular CCDTL concept is intended to cover the energy range from 40 to 90 MeV and consists of modules of ~5 m length made of 3 or 4-gap DTL tanks linked by coupling cells. The focusing quadrupoles are placed between tanks, and are aligned independently from the RF structure. The CCDTL prototype consists of two half tanks connected by a coupling cell and requires an RF power of 120 kW to achieve the design gradient. RF tests will be made at low and high power, the latter up to a 20% duty cycle. This paper introduces the main features of this CCDTL design, describes the RF and mechanical design of the prototype and presents the first measurement results.
TUP03	Design of the LINAC4, A New Injector for the CERN Booster	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	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)	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	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.
TUP07	A Linac-to-Booster Injection Line for Transverse Matching and Correlated Injection Painting	303
	R. Garnett, L. Rybarcyk LANL, Los Alamos, New Mexico
	In this paper we discuss a compact linac-to-booster ring transfer line originally proposed for the Los Alamos Advanced Hydrotest Facility design to vertically inject a 157 MeV H^- beam from the linac into a 10 GeV booster. TRACE 3-D and PARMILA simulations were used to demonstrate the performance of the transfer line to deliver the required transverse beam to the foil while also allowing correlated longitudinal injection painting. Schemes for both transverse and longitudinal matching are important for high-intensity ring applications where low beam loss operation is desirable. The main features of the beam line layout, a proposed longitudinal painting scheme, and the simulation results will be discussed.
TUP08	Carbon Ion Injector Linac for a Heavy Ion Medical Synchrotron	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	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	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	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.
TUP20	Some Relevant Aspects in the Design and Construction of a 30-62 MeV Linac Booster for Proton Therapy	336
	V.G. Vaccaro, S. Falco Naples University Federico II, Mathematical, Physical and Natural Sciences Faculty, Napoli A. D'Elia Naples University Federico II, Napoli D. Davino Universita' degli Studi del Sannio, Benevento M.R. Masullo INFN-Napoli, Napoli
	Recent results in accelerator physics showed the feasibility of a coupling scheme between a cyclotron and a linac for proton acceleration. Cyclotrons with energies up to 30 MeV, mainly devoted to radioisotopes production, are available in a large number of medical centres. This suggested to design a linac booster able to increase the proton energy up to 62 MeV as required for treating tumours like the ocular ones. In this paper we will review the rationale of the project; we will discuss the basic design of a compact 3 GHz SCL (Side Coupled Linac) with a new approach to the linac cavities. Among the many challenges of such a project one of the most interesting is the tuning of the cavities. Because the tuning can be done only after assembling the system, it is difficult to detect which cavities are responsible for the detuning: indeed the resonant behavior of single cavity is lost since the resonances merge into the resonant modes of the whole system. It is shown how, from the measured mode frequencies of the system, it is possible to derive the unknown resonances of each cavity and then refine the tuning. The proposed procedure is quite general and is not restricted to the SCL.
WE201	Results from the Initial Operations of the SNS Front End and Drift Tube Linac	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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TH102	Overview of High Intensity Linac Programs in Europe	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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