JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
The beam commissioning of J-PARC linac has been started since November 2006, and the initial commissioning has been completed in September 2007. Since then, the linac beam has been supplied to the succeeding RCS (Rapid Cycling Synchrotron) for its commissioning with occasional linac beam studies for finer tuning. The emphasis of the linac tuning has been shifted to the characterization and stabilization of the beam parameters, and better beam availability has gradually been required for the linac operation. In this paper, we present the current linac performance and operational experience obtained so far after a brief review of the commissioning history. Remaining commissioning tasks and the future upgrade plan to increase the beam power are also discussed.
IHEP Beijing, Beijing
China Spallation Neutron Source (CSNS) consist of an H- linac as an injector of a rapid cycling synchrotron of 1.6 GeV. The 324 MHz rf linac is designed with beam energy of 81 MeV and a peak current of 30 mA. The linac design and R&D are in progress. A test stand of a Penning ion source is under construction. RFQ technology has been developed in ADS study, with beam energy of 3.5 MeV, a peak current of 47 mA at 7% duty factor and a beam transmission rate more than 94%. The first segment of the DTL tank has been fabricated. This paper will introduce the design and R&D status of the linac.
Soreq NRC, Yavne
ACCEL, Bergisch Gladbach
The Soreq Applied Research Accelerator Facility, SARAF, is currently under construction at Soreq NRC. SARAF is based on a continuous wave (cw), proton/deuteron rf superconducting linear accelerator with variable energy (5-40 MeV) and current (0.04-2 mA). SARAF is designed to enable hands-on maintenance, which implies beam loss below 10-5 for the entire accelerator. Phase I of SARAF consists of an ECR ion source, a LEBT section, a 4-rod RFQ, a MEBT section, a superconducting module housing 6 half-wave resonators and 3 superconducting solenoids, a diagnostic plate and a beam dump. Phase II will include 5 additional superconducting modules. The ECR source has been in routine operation since 2006, the RFQ has been operated with ions and is currently under characterization. The superconducting module rf performance is being characterized off the beam line. Phase I commissioning results, their comparison to beam dynamics simulations and Phase II plans will be presented.
GSI, Darmstadt
Funding: EU-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" program (CARE, contract number RII3-CT-2003-506395); EU-INTAS Project Ref. no. 06-1000012-8782
The present GSI accelerator chain will serve as an injector for FAIR. The linear accelerator UNILAC and the heavy ion synchrotron SIS18 should deliver up to 1012 U28+ particles/sec. In the past two years different hardware measures and a careful fine tuning of the UNILAC resulted in a 35% increase of the beam intensity to a new record of 1.25*1011 U27+ ions per 100μs or 2.3*1010 U73+ ions per 100μs. The increased stripper gas density, the optimization of the Alvarez-matching, the use of various newly developed beam diagnostics devices and a new charge state separator system in the foil stripper section comprised the successful development program. The contribution reports results of beam measurements during the high current operation with uranium beams (pulse beam power up to 0.65 MW). The UNILAC upgrade for FAIR will be continued by assembling a new front-end for U4+, stronger power supplies for the Alvarez quadrupoles, and versatile high current beam diagnostics devices. Additionally, the offered primary proton beam intensities will be increased by a new proton linac, which should be commissioned in 2013.
Fermilab, Batavia
ANL, Argonne
IUCF, Bloomington, Indiana
Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The High Intensity Neutrino Source (HINS) linac R&D program at Fermilab aims to construct and operate a first-of-a-kind, 60 MeV, superconducting H- linac. The machine will demonstrate acceleration of high intensity beam using superconducting spoke cavities from 10 MeV, solenoidal focusing optics throughout for axially-symmetric beam to control halo growth, and operation of many cavities from a single high power rf source for acceleration of non-relativistic particles.
IAP, Frankfurt am Main
RFQs are the new standard injector for a number of projects. The development of the 4-Rod RFQ structure has led to a number of interesting developments, which will be discussed with actual projects as examples. Recent work on the FAIR - p linac, the GSI - high charge state injector upgrade, the GSI - HITRAP, the new BNL - EBIS-RFQ, and the RFQ of the MSU - CW Reaccelerator will be presented and the status of these projects and will be discussed.
IAP, Frankfurt am Main
GSI, Darmstadt
Funding: Work supported by BMBF
The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum will comprise a short 175 MHz linac sequence consisting of a 1.4 m long 700 keV 4-rod type RFQ followed by a 50 cm IH-DTL for proton acceleration up to 2 MeV. The beam current is 200 mA at pulsed and 30 mA at cw operation. The aim is to have a very compact device driven by only one rf amplifier to reduce costs and required installation space. A coupling between the RFQ and the IH resonators by means of a galvanic connection is foreseen, which is realized by two brackets going right away through a common partitioning end flange lid. The accelerators could also be driven separately by just removing the brackets. The distance between the end of the RFQ electrodes and the middle of the first DTL gap is only 5 cm, there is no additional beam optics in between. Preliminary beam dynamics and rf simulations have been carried out together with accompanying measurements on rf models.
IAP, Frankfurt am Main
The Frankfurter neutron source at Stern-Gerlach-Zentrum (SGZ) uses a proton injector as a driver for the 7Li(p,n) neutron production. A volume type ion source will deliver a 100 keV, 200 mA proton beam continuously. It is intended to use a LEBT section consisting of four solenoids to transport the beam and to match it into the acceptance of the RFQ. A chopper system between solenoid 2 and 3 will provide beam pulses with a length of about 100 ns with a repetition rate of 250 kHz. The RFQ and the following IH drift tube LINAC will be coupled together to achieve an efficiency beam acceleration. Furthermore only one power amplifier will be needed to provide the rf power for both accelerator stages. The Mobley type bunch compressor will merge 7 micro-bunches formed in the accelerator module to one single 1ns bunch with an estimated peak current of about 8.6 A. A rebuncher will provide the post acceleration at a final beam energy adjustable between 1.8 and 2.4 MeV. The whole injector suffers from the high beam intensity and therefore high space charge forces. It will gives the opportunity to develop new accelerator concepts and beam diagnostic technics.
KAERI, Daejon
A 20 MeV proton accelerator, which consists of a 50 keV injector, a 3 MeV RFQ and a 20 MeV DTL, has been tested by Proton Engineering Frontier Project (PEFP) at Korea Atomic Energy Research Institute (KAERI. The operation conditions are 20 MeV, 20 mA peak current, 50 μs pulse length with a 1 Hz repetition rate due to the limited radiation shielding. The accelerator was tuned to reach to the above operating conditions. Moreover, an irradiation facility with external beam has been installed to supply the proton beam for the user and irradiation test. In this paper, we present results from tuning operation and the irradiation tests.
CERN, Geneva
Linac4 is a 160 MeV, 40 mA H- linear accelerator which will be the source of particles for all CERN proton accelerators from 2013. Its construction has started in 2008, as part of a program for the progressive replacement or upgrade of the LHC injectors during the next decade. Linac4 will initially inject into the PS Booster and at a later stage into a 4 GeV Superconducting Proton Linac (SPL), which could ultimately be upgraded to high duty cycle operation. For this reason accelerating structures, rf hardware and shielding of Linac4 are dimensioned for higher duty from the initial phase. Linac4 is normal-conducting, 80 m long and consists of an rf volume ion source, an RFQ, a beam chopping section and a cascade of three different types of 352 MHz accelerating structures. Its main design requirements are high reliability, high beam brightness and low beam loss. The accelerator will be housed in an underground tunnel on the CERN site, which can eventually be extended to the SPL, with equipment installed in a surface building above. The main parameters, the status of the main components, the planning, the project organisation and the civil engineering infrastructure are presented.
STFC/RAL/ISIS, Chilton, Didcot, Oxon
Imperial College of Science and Technology, Department of Physics, London
Fundación Tekniker, Elbr (Guipuzkoa)
University of Warwick, Coventry
Bilbao, Faculty of Science and Technology, Bilbao
Fundación TEKNIKER, Eibar (Gipuzkoa)
STFC/RAL, Chilton, Didcot, Oxon
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
Elytt Energy, Madrid
High power proton accelerators (HPPAs) with beam powers in the several megawatt range have many applications including drivers for spallation neutron sources, neutrino factories, waste transmuters and tritium production facilities. The UK's commitment to the development of the next generation of HPPAs is demonstrated by a test stand being constructed in collaboration between RAL, Imperial College London, the University of Warwick and the Universidad del Pais Vasco, Bilbao. The aim of the RAL Front End Test Stand is to demonstrate that chopped low energy beams of high quality can be produced and is intended to allow generic experiments exploring a variety of operational conditions. This paper describes the current status of the RAL Front End Test Stand.
TRIUMF, Vancouver
The ISAC-III proposal is a ten year plan to triple the amount of radioactive ion beam (RIB) time at the facility. The plan includes the addition of two new independent target stations with a design suitable for actinide target materials, a second 500 MeV proton beam line from the TRIUMF cyclotron and a new 50 MeV electron linac as a complementary driver to provide RIBs through photo-fission. The two new target stations will require a new mass-separator and low-energy beam-transport complex to deliver the additional beams to the ISAC experimental facilities. It is also proposed to install a new linear accelerator section to provide the capability for two simultaneous accelerated RIBs to experimenters. This paper will describe the proposed installations in the low-energy transport and accelerator sections of the ISAC complex.
GSI, Darmstadt
IAP, Frankfurt am Main
For injection into the ion trap facility HITRAP, the GSI accelerator complex has the unique possibility to provide beams of highly stripped ions and even bare nuclei up to Uranium at an energy of 4 MeV/u. The HITRAP facility consists of linear 108 MHz-structures of IH- and RFQ-type to decelerate the beams further down to 6 keV/u for capturing in a large penning trap for cooling purpose. The installation is completed except of the RFQ-tank. During commissioning periods in 2007 64Ni28+ and 20Ne10+ beam was used to investigate the beam optics from the experimental storage ring extraction to the HITRAP double-drift-buncher system. In 2008 the IH-structure decelerator and the downstream matching section was examined with 197Au79+ beam. Comprehensive beam diagnostics were installed: Faraday cups, tubular and short capacitive pick ups, SEM grids, YAG scintillation screens, a single shot pepperpot emittance meter, and a diamond detector for bunch shape measurements. Results of the extensive measurements are presented.
DAE/VECC, Calcutta
An ISOL (Isotope Separator On Line) type of RIB (Radioactive Ion Beam) facility* is being developed at our centre. The post-acceleration scheme will consist of a Radio Frequency Quadrupole** (RFQ) followed by a few IH LINAC cavities - further augumentation of energy using SC QWRs will be taken up at a later stage. The first two IH cavities have been designed for 37.6 MHz frequency like the preceding RFQ to keep the rf defocusing smaller. Explosively bonded copper on steel has been used for the fabrication of the IH cavities (1.72 m inner diameter, 0.6 m and 0.87 m lengths) and the inner components have been made out of ETP grade copper. Also, we have adopted an octagonal cavity structure to avoid fabrication complicacies. Thermal analysis of the cavities have been carried out and cooling configurations have been optimized accordingly to control the temperature rise of the LINACs. Detailed mechanical analysis has been carried out to reduce the deflection of the LINAC components under various loads. Design and fabrication aspects of these two cavities and results of the low power tests will be reported in this paper.
* Alok Chakrabarti et. al. ; Proc. Part. Accl. Conf. 2005, pp-395.
** Alok Chakrabarti et. al. ; Nucl. Instr. & Meth., A535 (2004) 599.
DAE/VECC, Calcutta
An ISOL type Rare Isotope Beam (RIB) Facility is being developed at VECC, Kolkata around the existing K=130 room temperature cyclotron. The possibility of using the photo-fission production route using a 50 MeV electron linac is also being explored. The production target and a 6.4 GHz ECR based charge-breeder system will lead to two beam lines. The first one, a low energy beam transport (LEBT) line consisting of a 1.7 m long, 33.7 MHz RFQ, will be dedicated to material science & other ion-beam based experiments. The second, post-acceleration beam line will accelerate the beams to 1.3 MeV/u using a longer, 3.4 m RFQ and a series of IH linear accelerators. In the first stage, the beam energy will be about 400 keV/u using three modules of linacs. Subsequently the energy will be boosted to about 1.3 MeV/u. Some of the systems have already been installed and made operational. The LEBT line has been tested and stable ion beams accelerated to 29 keV/u with high efficiency in the 1.7 m RFQ. The 3.4 m RFQ and the first IH Linac tank are under installation in the post-acceleration beam line. In this contribution an overview of the present status of the facility will be presented.
RIKEN Nishina Center, Wako, Saitama
Present status of the RIKEN heavy-ion linac (RILAC) will be reported, which has been used for the injector to the RIKEN RI-beam factory since 2006 as well as for the nuclear physics experiments on superheavy elements since 2002. An alternative injector to the RI-beam factory, consisting of a superconducting ECR ion source, an RFQ, and three DTLs, will be also discussed. The construction of the ion source will be completed in this year and the extraction test of the beams will be started from 2009. An RFQ linac, originally developed for the ion implantation*, was given to RIKEN through the courtesy of Kyoto University. Reconditioning of this RFQ is underway, which will be modified for the new injector in the near future.
*H. Fujisawa: Nucl. Instrum. Methods A345, 23 (1994).
PKU/IHIP, Beijing
Funding: Supported by NSFC (10775009)
The methodology for low energy spread RFQ beam dynamics design has been studied for 14C+ AMS application. This paper will present a low energy beam dynamics and rf design for a new trapezoidal IH-RFQ. It will accelerate 14C from 40 keV to 500 keV with the length of 1.1 m; operate at 104 MHz with the rf peak power less than 27 kW. The transmission efficiency is better than 95% and the energy spread is as low as 0.6%. The rf structure design and its rf efficiency have been studied by electromagnetic simulation. It shows such trapezoidal IH-RFQ has higher operating frequency than normal IH-RFQ, and it will have more longitudinal accelerating efficiency.
PKU/IHIP, Beijing
Funding: supported by NSFC 10455001
Longer the RFQ length is, lower kinetic energy gain per unit length is; lower the injection energy DTL is, much higher accelerating efficiency is; more accelerating gaps at DTL entrance means stronger transverse focusing is needed for the beam. SFRFQ is such an intermediate structure, which combines RFQ and DTL together, it can increase the accelerating efficiency at RFQ high energy end by inserting gap acceleration between RFQ electrodes while provide strong focusing by RFQ focusing field. One prototype cavity has been manufactured and will be used as a post accelerator of ISR RFQ to accelerate O+ from 1 MeV to 1.6 MeV in 1meter. A code SFRFQCODEV1.0 was developed for the beam dynamics design. The rf conditioning and full rf power test has been carried out. The intervane or gap voltage have reached 86 kV at 29 kW with 1/6 duty cycle and repetition frequency 166 Hz. The initial beam test results will also be presented in this paper.
JINR, Dubna, Moscow Region
IHEP Protvino, Protvino, Moscow Region
Goal of the NICA/MPD project under realization at JINR is to start in the coming 5-7 years an experimental study of hot and dense strongly interacting QCD matter and search for possible manifestation of signs of the mixed phase and critical endpoint in heavy ion collisions. The Nuclotron-based Ion Collider fAcility (NICA) and the Multi Purpose Detector (MPD) are proposed for these purposes. The NICA collider is aimed to provide experiment with heavy ions like Au, Pb or U at energy up to 3.5 x 3.5 GeV/u with average luminosity of 1027 cm-2s-1. The existing Nuclotron injection complex consists of HV fore-injector and Alvarez-type linac LU-20. The LU-20 accelerates the protons up to the energy of 20 MeV and ions at Z/A=0.33 up to the energy of 5 MeV/u. New injector designed for efficient operation of the NICA facility is based on Electron String Ion Source providing short (< 10 ns) and intensive (up to 10 mA) pulses of U32+ ions, one section of RFQ and four sections of RFQ Drift Tube Linac accelerating the ions at Z/A=0.12 up to 6 MeV/u of the kinetic energy. General parameters of the injector are discussed.
ITEP, Moscow
GSI, Darmstadt
Funding: Work supported by the European Community INTAS Project Ref. no. 06-1000012-8782.
For the operation of the GSI-accelerator chain as an injector for the future FAIR facility a considerable increase of the heavy ion beam intensity by a factor 3-5 at the end of the UNILAC is required. The bottleneck of the whole UNILAC, is the front-end system of the High Current Injector. It is shown that the transverse RFQ-acceptance can be significantly increased while the emittance growth can be reduced. Both goals are achieved with only a moderate change of the RFQ electrode geometry; the intervane voltage raised from 125 kV to 155 kV keeping the design limit of the maximum field at the electrode surface. The changed resonant frequency can be compensated with a relatively small correction of the carrying rings. The beam parameters in the final focusing elements of the LEBT were improved together with the input radial matcher design; the length of the gentle buncher section was considerably increased to provide slow and smooth bunching resulting in a reduce influence of space charge forces. DYNAMION-simulation with the modified electrode design resulted in an increase of U4+-beam current of up to 20 emA. It is planned to start the upgrade measure in spring 2009.
IAP, Frankfurt am Main
BNL, Upton, Long Island, New York
A new RFQ is being built as a part of the new EBIS-linac at BNL. The RFQ accepts highly charged ions from the EBIS ion source with energy of 17 keV/u and ion currents of up to 10 mA. The operation frequency will be 100.625 MHz . The design had been optimized to get a rather short structure with LRFQ=3.1 m with moderate electrode voltages of UQ = 70 kV. The resonant insert has a cooled base plate and solid stems and vane-electrodes. The mechanical design is very stiff, with a precise base-structure. The top lid along the RFQ allows installation, alignment, inspection and maintenance. After the mechanical alignment of the electrodes the longitudinal electrode voltage distribution will be adjusted with tuning plates between the stems. The properties of the RFQ, the results of the tuning and the status of the project will be discussed.
DAE/VECC, Calcutta
Radio Frequency Quadrupole (RFQ) would be the first post accelerator for the upcoming Rare Isotope Beam (RIB) facility at Variable Energy Cyclotron Centre (VECC), India. A 33.7 Mhz RFQ capable of accelerating stable as well as RI beams of q/A > 1/16 to about 30 keV/u has already been constructed and operational since September 2005 . This has been installed in a dedicated beam line for doing material science experiments. Another 3.4 m long RFQ resonating at 37.6 Mhz and capable of accelerating heavy ion beams up to 98 keV/u have been fabricated which is to be installed in the beam line for the VEC-RIB facility. The physical parameters,rf test along with the measurements of accelerated beams from RFQ would be presented.
INFN/LNL, Legnaro, Padova
Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Padova
The IFMIF-EVEDA (Engineering Validation and Engineering Design Activities) project foresees the construction of a high intensity deuteron accelerator up to 9 MeV, with the characteristics required for the actual IFMIF facility. The linac will be installed in Rokkasho, and INFN is in charge of the construction of a 5 MeV, 125 mA, deuteron RFQ operating at 175 MHz. In this article the beam dynamics design of this challenging RFQ is described, namely the design, the main outcomes in terms of beam particles physics, and finally the study of mechanical and rf field error tolerances. The RFQ design method has been aimed to the optimization of the voltage and R0 law along the RFQ, the accurate tuning of the maximum surface field and the enlargement of the acceptance in the final part of the structure. As a result this RFQ is characterized by a length shorter than in all previous design, very low losses (especially at higher energy) and small rf power dissipation.
INFN/LNL, Legnaro, Padova
Università degli Studi di Milano, Milano
The RFQ of IFMIF-EVEDA project is characterized by very challenging specifications, with 125 mA of deuteron current accelerated up to 5 MeV. Upon beam dynamics studies, it has been chosen a law for the variation of R0 and voltage along the structure; this law provides a significant reduction in terms of structure length, beam losses and rf power consumption. Starting from these outcomes, the rf study of the RFQ, aimed at determining the optimum design of the cavity shape, was performed. The stabilization issues were also addressed, through the analysis of the RFQ sensitivity to geometrical errors, by means of perturbative theory-based algorithms developed for this purpose . Moreover the determination of the main 3D details of the structure was also carried out. In this article the results of the rf studies concerning the above-mentioned topics are outlined.
Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Padova
INFN/LNL, Legnaro, Padova
CERN, Geneva
The Legnaro National Laboratory (LNL) is building the 30 mA, 5 MeV front end injector for the production of intense neutron fluxes for interdisciplinary application. This injector comprises a proton source, a low energy beam transport line (LEBT), a radio frequency quadrupole (RFQ) and a beam transport line designed to provide a 150 kW beam to the berillium target used as neutron converter. The RFQ, developed within TRASCO project for ADS application, is designed to operate cw at 352.2 MHz. The structure is made of OFE copper and is fully brazed. The RFQ is built in 6 modules, each approximately 1.2 meter long. This paper covers the mechanical fabrication, the brazing results and acceptance tests for the various modules.
RLNR, Tokyo
In order to obtain high intensity ion beams from a linear accelerator (linac) stably, it is necessary to suppress the defocusing force due to the space charge effect. The defocusing force is extremely strong in low energy and high intensity beams. Therefore, high intensity ion beam acceleration in the low energy region is one of the most difficult conditions to achieve. One of the solutions is the relaxation of the defocusing force by dividing the high intensity beam into several beams. Thus, a multibeam IH type Radio Frequency Quadrupole (IH-RFQ) linac has been proposed for a high intensity injector system. In particular, we have been developing a two-beam type IH-RFQ cavity as a prototype of the multibeam type IH-RFQ by using computer code. This prototype has the capability of accelerating charged particles to mass ratio (q/A) greater than 1/6 from 5 keV/u up to 60 keV/u. The expected total output current is 87.2 mA for the total input beam current of 120 mA.
CERN, Geneva
CEA, Gif-sur-Yvette
The first stage of acceleration in Linac4, the new 160 MeV CERN H- injector, is a 352 MHz, 3 m long Radiofrequency Quadrupole (RFQ) Accelerator. The RFQ will capture a 70 mA, 45 keV beam from the rf source and accelerate it to 3 MeV, an energy suitable for chopping and injecting the beam in a conventional Drift Tube Linac. Although the RFQ will be initially operated at low duty cycle (0.1%), its design is compatible with higher duty cycle (10%) as the front-end for a possible high-intensity upgrade of the CERN linac facility. The RFQ will be of the brazed-copper design and will be built and assembled at CERN. Beam dynamics design allows for a compact structure made of a single resonant unit. Field symmetry is ensured by fixed tuners placed along the structure. In this paper we present the rf and mechanical design, the beam dynamics and the sensitivity to fabrication and to rf errors.
Fermilab, Batavia
ANL, Argonne
Fermilab is designing and building the HINS front-end test facility. The HINS proton linear accelerator consists of a normal-conducting and a superconducting section. The normal-conducting (warm) section is composed of an ion source, a 2.5 MeV radio frequency quadrupole (RFQ), a medium energy beam transport, and 16 normal-conducting crossbar H-type cavities that accelerate the beam to 10 MeV. Production of 325 MHz 4-vane RFQ is recently completed. This paper presents the design concepts for this RFQ, the mechanical design and tuning results. Issues that arose during manufacturing of the RFQ will be discussed and specific corrective modifications will be explained. The preliminary results of initial testing of RFQ at the test facility will be presented and comparisons with the former simulations will also be discussed.
Fermilab, Batavia
Similar to many other linear accelerators, the High Intensity Neutron Source requires an RFQ for initial acceleration and formation of the bunched beam structure. The RFQ design includes two main tasks: a) the beam dynamics design resulting in a vane tip modulation table for machining and b) the resonator electromagnetic design resulting in the final dimensions of the resonator. The focus of this paper is on the second task. We report complete and detailed rf modeling on the HINS RFQ resonator using simulating codes CST Microwave Studio (MWS) and Ansoft High Frequency Structure Simulator (HFSS). All details of the resonator such as input and output radial matchers, the end cut-backs etc. have been precisely determined. Finally in the first time a full size RFQ model with modulated vane tips and all tuners installed has been built, and a complete simulation of RFQ tuning has been performed. Comparison of the simulation results with experimental measurements demonstrated excellent agreement.
BNL, Upton, Long Island, New York
Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka
Department of Energy Sciences, Tokyo Institute of Technology, Yokohama
Direct injection scheme was proposed in 2000 at RIKEN in Japan. The first beam test was done at Tokyo Institute of Technology using a CO2 laser and an 80 MHz 4 vane RFQ in 2001, and further development continued in RIKEN. In 2006, all the experimental equipment was moved to BNL and a new development program was started. We report on our recent activities at BNL including the use of a frozen gas target for the laser source, low charge state ion beam production and a newly developed laser irradiation system.
BNL, Upton, Long Island, New York
Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka
Direct plasma injection scheme has been developed recently for producing and accelerating intense pulsed heavy ion beams with high charge states. This new method uses a combination of a laser ion source and an RFQ linear accelerator and its repetition rate is determined by the laser system. Fixed field alternating gradient (FFAG) accelerator is being focused as a high repetition synchrotron. An integration of these new techniques enables one to produce a large beam power with heavy ion beams. At Ito campus of Kyushu University, a proton FFAG is being installed. We propose to construct a new injector linac for the FFAG. The planned operating parameters are 100 Hz repetition rate, 20 mA of fully stripped carbon beam and 200 MHz operating frequency for the linac.
NSCL, East Lansing, Michigan
The Re-accelerator being developed at the Michigan State University is a major component of a novel system proposed at the NSCL to first stop the high energy RIBs by the in-flight particle fragmentation method in a helium filled gas system, then increase their charge state with an Electron Beam Ion Trap (EBIT) charge breeder, and finally re-accelerate them to about 3 MeV/u, in order to provide opportunities for an experimental program ranging from low-energy Coulomb excitation to transfer reaction studies of astrophysical reactions. The accelerator system consists of a Low Energy Beam Transport (LEBT) with an external multi-harmonic buncher, a radio frequency quadrupole (RFQ) followed by a superconducting linac and a High Energy Beam Transport (HEBT). The superconducting linac will use quarter-wave resonators with bopt of 0.047 and 0.085 for acceleration and superconducting solenoid magnets for transverse focusing. The paper will discuss the recent progress of R&D and beam dynamics studies for the MSU Re-accelerator.
GSI, Darmstadt
HIT, Heidelberg
A clinical facility for cancer therapy using energetic proton and ion beams (C, He and O) has been installed at the Radiologische Universitätsklinik in Heidelberg, Germany. It consists of two ECR ion sources, a 7 MeV/u linac injector, and a 6.5 Tm synchrotron to accelerate the ions to energies of 430 MeV/u. The linac comprises a 400 keV/u RFQ and a 7 MeV/u IH-DTL operating at 216.8 MHz and has been commissioned successfully in 2006. Yet the overall achieved transmission through the injector linac did not exceed 30% due to a mismatch of the beam at the RFQ entrance. Thus a detailed upgrade programme has been started to exchange the RFQ with a new radial matcher design, to correct the alignment and to optimize beam transport to the IH-DTL. The aim is to achieve a sufficient linac transmission above 60%. The new design of the RFQ has been finished in 2007 and the RFQ is currently in production. A test bench comprising a full ion source and LEBT setup to commission the RFQ in 2008 is under construction at Danfysik in Danemark. The current status of this upgrade programme will be reported in this contribution.
RLNR, Tokyo
U. Sapientia, Targu Mures
BNL, Upton, Long Island, New York
Department of Energy Sciences, Tokyo Institute of Technology, Yokohama
We succeeded to accelerate very intense carbon ions with the Direct Plasma Injection Scheme (DPIS) using Laser ion source in 2001 and 2004. The peak current reached more than 60 mA of C4+ and 18 mA of C6+ with pulse width of 2-3 x 10-6 sec. We believe that these techniques are quite effective for pulse accelerator complexes such as linear accelerator and synchrotron (heavy-ion cancer therapy). In heavy cancer therapy, carbon stripper section is rejected by accelerated C6+. One turn injection of high intensity (6 mA) C6+ ion is possible to enough in synchrotron. We study a new hybrid single cavity linac combined with radio frequency quadrupole (RFQ) electrodes and drift tube(DT) electrodes into a single cavity. The hybrid linac is able to downsize the linac system and reduce the peripheral device. Using DPIS with Laser ion source, we study POP hybrid single-cavity accelerator of C6+ for injector linac of C cancer therapy. The linac is designed to accelerate 6 mA C6+ ion from 40 keV/u to 2 MeV/u with YAG Laser ion source. We will present the design procedures of this hybrid linac, which is based on a three-dimensional electromagnetic field and particle orbit calculation.
Linac Systems, LLC, Albuquerque, New Mexico
A 2.5 MeV, 20 mA, cw, proton linac for the Boron Neutron Capture Therapy medical application is under construction at Linac Systems. The system consists of a 25 keV microwave ion source, a solenoid lens based low energy beam transport system, a 0.75 MeV RFQ linac, a 2.5 MeV RFI linac, and the necessary service systems. Because of the superb low energy capabilities of the RFI structure, the RFQ linac need only go to 0.75 MeV, resulting in a cavity dissipation of 74 kW for the RFQ section. Because of the high rf efficiency of the RFI structure, the cavity dissipation is only 35 kW for the RFI section. Extensive thermal studies have been made to accommodate these cw heat load. The beam power is 50 kW. The rf power system is designed for an average power output of 200 kW. The RFQ and RFI sections are coupled into a single resonant unit by a quarter-wave-stub resonant coupler. The combination is driven at a single point in the RFQ structure. The total length of the linac is 2.6 meters. The system is scheduled for completion by early fall (2008).
CEA, Gif-sur-Yvette
The purpose of the IFMIF-EVEDA (International Fusion Materials Irradiation Facility-Engineering Validation and Engineering Design Activities) demonstrator is to accelerate a 125 mA cw deuteron beam up to 9 MeV. Therefore, the project requires that the ion source and the low energy beam transport (LEBT) line deliver a 140 mA cw deuteron beam with an energy of 100 keV and an emittance of 0.25 π .mm.mrad (rms normalized) at the entrance of the RFQ. The deuteron beam is extracted from a 2.45 GHz ECR source based on the SILHI design*. A LEBT with a two solenoids focusing system is foreseen to transport and adapt the beam for the RFQ injection. In order to validate the LEBT design, intensive beam dynamics simulations have been carried out using a parallel implementation of a particle-in-cell 3D code which takes into account the space charge compensation of the beam induced by the ionisation of the residual gas. The simulations results (in particular from the emittance growth point of view) performed under several conditions of gas species or gas pressure in the beam line are presented.
*R. Gobin et al, Rev. Sci. Instrum. 79, 02B303 (2008).
CEA, Gif-sur-Yvette
INFN/LNL, Legnaro, Padova
CIEMAT, Madrid
One major subsystem of IFMIF (International Fusion Materials Irradiation Facility) is its accelerator facility, consisting of two 175 MHz CW accelerators, each accelerating a deuteron beam of 125 mA to the energy of 40 MeV. This high power beam, 10 MW, induces challenging issues that lead to plan a first phase called EVEDA (Engineering Validation and Engineering Design Activity), where only the portion up to 9 MeV of one accelerator will be constructed and tested. For these accelerators, the Parameter Design phase is about to be completed. This paper presents the status of these studies. Due to the very high beam intensity, particular efforts have been dedicated to minimise the space charge effect that can strongly increase the beam size via the halo, and the losses that can prohibit the requested hand-on maintenance. For that, Beam Dynamics simulations have been performed with 106 macro-particles, and a great vigilance has been granted to the emittance growth and the particles on the beam edge. Several possible solutions are presented, for which advantages and drawbacks to fulfil the specifications are discussed.
INFN/LNL, Legnaro, Padova
Soreq NRC, Yavne
IPN, Orsay
CEA, Gif-sur-Yvette
TRIUMF, Vancouver
Funding: We acknowledge the financial support of the European Community under the FP6 "Research Infrastructure Action-Structuring the European Research Area" EURISOL DS Project Contract No. 515768 RIDS.
A 1 GeV, 5 mA cw superconducting proton/H- linac, with the capability of supplying cw primary beam to up to four targets simultaneously by means of a new beam splitting scheme, is under study in the framework of the EURISOL DS project which aims to produce an engineering-oriented design of a next generation European Radioactive beam facility. The EURISOL driver accelerator would be able to accelerate also a 100 muA 3He beam up to 2 GeV, and a 5 mA deuteron beam up to 200 MeV. The linac characteristics and the status of the beam dynamics studies will be presented.
Imperial College of Science and Technology, Department of Physics, London
University of Warwick, Coventry
STFC/RAL/ISIS, Chilton, Didcot, Oxon
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
In order to contribute to the development of high power proton accelerators in the MW range, to prepare the way for an ISIS upgrade and to contribute to the UK design effort on neutrino factories, a front end test stand (FETS) is being constructed at the Rutherford Appleton Laboratory (RAL) in the UK. The aim of the FETS is to demonstrate the production of a 60 mA, 2 ms, 50 pps chopped beam at 3 MeV with sufficient beam quality. The results of numerical simulations of the particle dynamics from the charge separation dipole behind the ion source to the end of the MEBT will be presented. Previous measurements showed that the emittance of the beam delivered by the ion source exceeded our expectations by more than a factor of 3. Since then various changes in the beam extraction/post accelerator region reduced the beam emittance by a factor of 2. Simulations of the particle dynamics in the FETS based on distributions gained from recent measurements of the transversal beam emittance behind the ion source will be presented and the results for different input distributions discussed.
ANL, Argonne
ORNL, Oak Ridge, Tennessee
Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC-02-06CH11357.
In an effort to simulate the SNS linac using the beam dynamics code TRACK and to benchmark the results against the recent commissioning data, we have started updating TRACK to support SNS-type elements such as DTL's and CCL's. After successfully implementing and simulating the DTL section of the SNS linac*, we have implemented the CCL section and the high energy superconducting (SC) section up to 1 GeV. Results from end-to-end simulations of the SNS linac using TRACK will be presented and compared to simulations using other codes and to the recent commissioning data.
*"First TRACK Simulations of the SNS linac", B. Mustapha et al., in Proceedings of Linac-06 Conference, Knoxville, Tennessee, August 21-25, 2006.
KEK/JAEA, Ibaraki-Ken
The J-PARC linac has been successfully commissioned up to its design energy and almost design peak intensity. The unique methods and hardware features adopted in the J-PARC linac, such as the Cs-free H- ion source, macro-pulse generation method, stable one-shot operation method, rf chopper system related with the J-PARC 30mA-RFQ (Radio Frequency Quadrupole linac) design and its operation parameter, one-turn injection method into the following J-PARC RCS (Rapid Cycling Synchrotron), transverse matching using TRACE3D PMQ (Permanent Magnet Quadrupole) elements approximating the fringe field effects of the electro-quadrupole magnets, 2 cavity behavior of SDTL (Separated Drift tube Linac) fed with one Klystron and so on, will be reported in this talk.
IPN, Orsay
The superconducting linac for the SPIRAL2 radioactive ion beam facility at GANIL is in the construction phase. The prototype components have been constructed and are being tested. A status report on the activities and future plans will be given.
IAP, Frankfurt am Main
GSI, Darmstadt
Funding: Work supported by BMBF under contract 06FY160I.
The Heavy highly charged Ion TRAP (HITRAP) project at GSI is in the commissioning phase. Highly charged ions up to U92+ provided by the GSI accelerator facility will be decelerated and subsequently injected into a large Penning trap for cooling to the MeV/u energy level. A combination of an IH- and an RFQ-structure decelerates the ions from 4 MeV/u down to 6 keV/u. In front of the decelerator a double drift-buncher-system is provided for phase focusing and a final de-buncher integrated in the RFQ-tank reduces the energy spread in order to improve the efficiency for beam capture in the cooler trap*. This contribution concentrates on the beam dynamics simulations and corresponding measurements in the commissioning beam times up to the position of the entrance to the RFQ. Single-shot emittance measurements at higher energies using the GSI pepper pot device and construction of a new device using Micro-Channel Plate technology for low energies as well as profile measurements are presented.
*HITRAP webpage of AP division at GSI, http://www.gsi.de/forschung/ap/projects/hitrap/index_e.html
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
STFC/RAL/ISIS, Chilton, Didcot, Oxon
STFC/RAL, Chilton, Didcot, Oxon
Funding: Work supported by EU/FP6/CARE (HIPPI) RII3-CT-2003-506395
Among present challenges for beam diagnostics and instrumentation are issues presented by high beam intensity, brightness, resolution and the need to avoid inserting mechanical parts into the beam. This very often means applying non-destructive methods, which avoid interaction between ions and mechanical parts and, furthermore, allow on-line measurements during normal beam operation. The preferred technique for H- beams is the photo-detachment process where (laser) light within the range of 400-1000 nm has a sufficient continuous cross section to neutralize negative ions. The actual diagnostics are then applied to either the neutrals produced or the electrons. The latter are typically used for beam profiles whereas neutrals are more suitable for emittances, and form the subject of the present paper. This provides an overview of the basic features of the diagnostic technique, followed by a more intensive discussion of some experimental and theoretical aspects with emphasis on computing the 4 dimensional emittance using a method called Maximum Entropy (MaxEnt).
ORNL, Oak Ridge, Tennessee
ORNL RAD, Oak Ridge, Tennessee
Funding: *SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy
During the first three years, the Spallation Neutron Source is ramping up the rep rate, pulse length, and beam current to reach 1 to 1.4 MW beam power in 2009. This challenges the Front-end with the H- source designed and built by Lawrence Berkeley National Laboratory. Early in 2007, the low-energy beam transport needed to be modified to improve the availability for duty factors in excess of 0.2%. Late in 2007, the H- source needed to be modified to produce the required 25 mA LINAC beam current during the ~0.4 ms long pulses at 60 Hz. The optimistic 1.4 MW goal requires 38 mA LINAC beam current, which was demonstrated for 4 hours on 12/24/07. LBNL developed a cesium system that uses only 30 mg of Cs to minimize the risk to the adjacent electrostatic LEBT and RFQ. Improved procedures and configuration were needed to generate intense beam currents for long pulses (>0.2 ms). Now optimal beam currents are reached within eight hours of replacing the H- source. The beam decay appears to be as small as 1% per day, which is compensated by a gradual increase in rf power. The peak performance can be restored by slowly re-cesiating the converter without interupting the neutron production.
BNL, Upton, Long Island, New York
IAP, Frankfurt am Main
Funding: Work supported by the US Department of Energy and the National Aeronautics and Space Agency
A new heavy ion preinjector is presently under construction at Brookhaven National Laboratory. This preinjector uses an Electron Beam Ion Source (EBIS), and an RFQ and IH Linac, both operating at 100 MHz, to produce 2 MeV/u ions of any species for use, after further acceleration, at the Relativistic Heavy Ion Collider, and the NASA Space Radiation Laboratory. Among the increased capabilities provided by this preinjector are the ability to produce ions of any species, and the ability to switch between multiple species in 1 second, to simultaneously meet the needs of both physics programs. Fabrication of all major components for this preinjector is in process, with testing of the EBIS and RFQ starting this year. The status of this construction will be presented.
NIRS, Chiba-shi
AEC, Chiba
SHI, Tokyo
An interdigital H-mode structure drift tube linac (IH-DTL) with alternating phase focusing (APF) has been developed downstream of a 4-vane type RFQ linac at the National Institute of Radiological Sciences as a compact injector for a heavy-ion medical synchrotron. The rf frequency of both linacs is 200 MHz, and the total length of the two linacs is less than 6 m. They can accelerate heavy ions having a charge to mass ratio of 1/3 up to 4 MeV/u. The accelerated current of 12C4+ is as high as 380 electric μA, and beam transmission through the APF IH-DTL is better than 96%. This compact injector-linac scheme might give a possible solution for a compact cancer therapy facility with heavy-ion beams.
GSI, Darmstadt
The Heidelberg Ion-Beam Therapy Centre (HIT) is the first dedicated clinical synchrotron facility for cancer therapy using energetic proton and ion beams (C, He and O) in Europe. The accelerator consists of a 7 MeV/u, 217 MHz injector linac and of a 430 MeV/u synchrotron. The installation and commissioning of the linac has been performed gradually in three steps for the ion sources and the LEBT, for the 400 keV/u RFQ, and for the 20 MV IH-type drift tube linac. The initial commissioning of the linac was finished successfully in December 2006, the commissioning of the synchrotron and of the high-energy beam lines with beam was finished for two fixed-beam treatment places in December 2007. Commissioning of the heavy-ion gantry is still going on. The results of the linac commissioning will be reported as well as the experience of more than one year of linac operation. To provide optimum conditions for patient treatment, an intensity upgrade programme has been initiated for the linac. A copy of the HIT linac is presently installed at the Centro Nazionale di Adroterapia Oncologica (CNAO) in Pavia, Italy. The status of the CNAO linac will be also reported.
ANL, Argonne
Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC-02-06CH11357.
Accelerator simulations still do not provide everything designers and operators need to deploy a new facility with confidence. This is mainly because of limitations preventing realistic, fast-turnaround, end-to-end simulations of the beam from the source all the way through to a final interaction point and because of limitations in on-line monitoring that prevent a full characterization of the actual beam line. As a result, once a machine is built there can be a gap between the expected behavior of the machine and the actual behavior. This gap often corresponds to enormous work and significant delays in commissioning a new machine. To address the shortcomings of the existing beam dynamics simulation codes, and to fulfill the requirements of future hadron and heavy-ion machines, a starting point for a realistic simulation tool is being developed at ANL that will support detailed design evaluation and also fast turnaround computation to support commissioning and operation of the facility. The proposed simulations will be performed on the fast growing computing facility at ANL with peta-scale capability.
IAP, Frankfurt am Main
Funding: GSI, BMBF contr. No. 06F134I, EU contr. No. 516520-FI6W, RII3-CT-2003-506395, EFDA/99-507ERB500CT990061
Worldwide there is an increasing interest in new high intensity proton and ion driver linacs with beam powers up to several MW. A very challenging part of these accelerators is the low and medium energy section up to 100 MeV. Depending on the duty cycle room temperature or superconducting options are favoured. In both cases the Crossbar-H-mode (CH)-structure, developed at the IAP in Frankfurt is an excellent candidate. Room temperature as well as superconducting prototype cavities have been developed and tested successfully. A superconducting 19 cell low energy (beta=0.1) CH-cavity at 360 MHz reached effective gradients of 7 MV/m corresponding to an accelerating voltage of 5.6 MV. This cavity could be used for high intensity, cw operated linacs like accelerator driven systems (ADS, EUROTRANS) or the international fusion material irradiation facility (IFMIF). Additionally, the new proton injector for FAIR (325 MHz, 70 mA, 70 MeV) will use room temperature CH-cavities. Recent developments of this new type of a multi-cell drift tube cavity, beam dynamics issues and the tests of the prototypes will be presented.
GANIL, Caen
The SPIRAL2 project uses a RFQ, normal conducting rebunchers and a superconducting linac to accelerate high intensity beams of protons, deuterons and heavier ions. All cavities work at 88 MHz, the beta after of the RFQ is 0.04 and 3 rebunchers are located in the MEBT line, which accepts ions with A/q up to 6. The paper describes the RF design and the technological solutions proposed for an original 3-gap cavity, characterised by very large beam holes (60 mm) and providing up to 120 kV of effective voltage.
GANIL, Caen
The SPIRAL2 project uses an RFQ, normal conducting rebunchers and a superconducting linac to accelerate high intensity beams of protons, deuterons and heavier ions. All cavities work at 88 MHz, are independently phased and powered by amplifiers whose power ranges from a few kW to 250 kW. The paper describes the amplifier requirements, the proposed solutions and their status.
RAS/INR, Moscow
TRIUMF, Vancouver
In this report we consider room temperature DTL structure for heavy ions acceleration in energy range 150 keV/u - 400 keV/u. The structure design is based on known and proven solutions. Due to design idea, the structure has no end wall problem. It allows flexible segmentation in cavities and transverse focusing elements placing outside cavity. As compared to well known IH DTL, considered structure has smaller transverse dimensions and is designated for lower operating frequency. The structure promises high rf efficiency - with careful elements optimization calculated effective shunt impedance value is higher than 1.0 GOhm/m for operating frequency ~ 70 MHz, E~150 keV/u.
NSCL, East Lansing, Michigan
To meet the requirement of a small output longitudinal beam emittance from the reaccelerator, a triple-harmonic buncher operating at the fundamental frequency of 80 MHz upstream the Radio Frequency Quadrupole (RFQ) linac has been designed, manufactured and tested at the National Superconducting Cyclotron Laboratory (NSCL). The buncher consists of two coaxial resonators with a single gridded gap. One cavity provides both the fundamental and the third harmonic simultaneously with l/4 and 3l/4 modes respectively, while the other for the second harmonic with a l/4 mode. This buncher combines the advantages of using high quality factor resonator and only a pair of grids. Details on design considerations, electromagnetic simulations, and test results are presented.
GSI, Darmstadt
During the LINAC conference in Knoxville 2006 the operating frequency of the FAIR proton linac was fixed at 325.224 MHz. Even though the six CH-Structures need slightly different rf levels, the proton linac will be equipped with identical rf power sources. That applies although for the RFQ structure. To supply the FAIR accelerators with a good beam quality by the UNILAC as the high current heavy ion injector for FAIR, as well as an high duty factor accelerator for nuclear physics experiments, different upgrades and modifications have to be made at the rf components. In addition there has to be an upgrade for a planned 50% duty cycle mode, higher beam load within the post-stripper section as well as the provision of an excellent rf operation for the next 30 years. Discussions on possible collaborations with CERN in terms of LLRF and the combining of the procurement for tube amplifiers for bunching cavities are on the way. This paper describes the actual status of the proton linac rf system and the future requirements for the existing UNILAC rf systems.
Linac Systems, LLC, Albuquerque, New Mexico
Most small proton and other ion linacs involve two different linac structures, namely an RFQ linac section and some other, more efficient, linac structure, such as the Drift Tube Linac (DTL), the interdigital (Wideroe) linac, or the Rf Focused Interdigital (RFI) linac. Such linacs can benefit a lot by being resonantly coupled into a single resonant unit. The resonantly coupled structures can be driven by a single rf power system, through single rf drive loop, at a single rf frequency. The relative phase and relative amplitude of the fields in the two structures are locked by the resonant coupler. Such systems require no control of phase of the rf power. By designing the rf power system to track the resonant frequency of the combined structures, the control of the resonant frequencies of the two structures is greatly simplified. A simple, compact, resonant coupler, based on a quarter-wave-stub, will be described. Models of this resonant couple have been tuned and adjusted, and are scheduled to be tested at operating powers in the early fall (2008).
CEA, Gif-sur-Yvette
The International Fusion Materials Irradiation Facility (IFMIF) is based on two high power cw accelerator drivers, each delivering a 125 mA deuteron beam at 40 MeV to the common lithium target. The present design of the 5 MW IFMIF Linacs, as well as the description of the prototype accelerator to be built in Japan are presented: the injector including the 140 mA ion source and the magnetic focusing LEBT, the RFQ for the bunching and acceleration to 5 MeV, the MEBT for the proper injection into the Drift-Tube-Linac where the beam is accelerated to the final energy of 40 MeV. Recently, the Alvarez type DTL was replaced by a superconducting Half-Wave Resonator Linac to benefit from the advantages of the SRF technology, in particular the rf power reduction, plug power saving, ability to accelerate high intensity cw beams with high flexibility and reliability. Last, a HEBT section transports and tailors the beam as a flat rectangular profile on the flowing Lithium target. The design and technology choices will be validated during the EVEDA phase, which includes the construction of one full-intensity deuteron linac, but at a lower energy (9 MeV) at Rokkasho Mura in Japan.