GANIL, Caen
SPIRAL 2 is a new European facility for Radioactive Ion Beams being constructed at the GANIL laboratory (Caen, France). It is based on a High Intensity CW multi-ion Accelerator Driver (Superconducting Linac), delivering beams to a High Power Production system (converter, target, and ion source), producing and post-accelerating Radioactive Ion Beams with intensities never reached before. The major components of the accelerator (injectors and SC Linac), have been presently ordered. The number of tested components is rapidly growing. The Superconducting Linac Accelerator incorporates many innovative developments of the Quarter-Wave resonators and their associated cryogenic and RF systems. The first beam is expected during autumn 2011. The first operation is scheduled for late 2012 with an initial experimental program prepared in the framework of a European Project, with many other international collaborating partners.
NSCL, East Lansing, Michigan
IAP, Frankfurt am Main
Rare isotope beam (RIB) accelerator facilities provide rich research opportunities in nuclear physics. The National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) is constructing a RIB facility, called ReA3. It will provide unique low-energy rare isotope beams by stopping fast RIBs and reaccelerating them in a compact linac. ReA3 comprises gas stopper systems, an Electron Beam Ion Trap (EBIT) charge state booster, a room temperature radio frequency quadrupole (RFQ), a linac using superconducting quarter wave resonators (QWRs) and an achromatic beam transport and distribution line to the new experimental area. Beams from ReA3 will range from 3 MeV/u for heavy ions to about 6 MeV/u for light ions, as the charge state of the ions can be adjusted by the EBIT. ReA3 will initially use beams from NSCL's Coupled Cyclotron Facility (CCF). Later ReA3 will provide reacceleration capability for the Facility for Rare Isotope Beams (FRIB), a new national user facility funded by the Department of Energy (DOE) that will be hosted at MSU. The ReA3 concept and status of ReA3 will be presented, with emphasis on the comissioning of the facility, which is underway.
GSI, Darmstadt
ITEP, Moscow
IAP, Frankfurt am Main
To provide for the high beam currents as required of the FAIR project, the GSI Unilac High Current Injector (HSI) must deliver 18 mA of U4+ ions at the end of the prestripper section. With the design existing up to 2008, the RFQ could not reach the necessary beam currents at the RFQ output, as simulations had shown. Furthermore, parts of the existing LEBT must be modified, and a new straight source branch must be added to provide for the full required beam current. As a first step of an HSI frontend upgrade, the RFQ has been modernized in summer 2009 with a completely new electrode design. Commissioning of the HSI has shown that the transmission of the RFQ increased significantly (from 55% to 85% in high current Uranium operation, 95% in medium current operation). As expected, further bottlenecks for the transmission of the complete HSI (matching LEBT-to-RFQ, matching to the Superlens) have been detected. An upgrade of LEBT magnets is foreseen for 2010, the additional linear source branch will follow.
GSI, Darmstadt
IAP, Frankfurt am Main
The GSI linear accelerator UNILAC provides heavy ion beams at Coulomb barrier energies for search and study of super heavy elements. Typical cross-sections of 55 fb require beam doses of 1.4·1019 according to a beam time of 117 days. Several upgrades will reduce the beam time to only 16 days. A second injection branch with a 28GHz-MS-ECRIS anticipates a factor of 10 in particle intensity. By a new cw rfq-structure all accelerator tanks are suitable for a duty cycle of at least 50% instead of 25% presently. Due to this, thermal power increase of 19 rf-amplifiers eased by higher ion charge states of the ECRIS is necessary. Finally the UNILAC timing system controlling 50Hz pulse-to-pulse operation of up to six beams differing in ion species and energy has to be modified considering beam diagnostics electronics and pulsable magnets. The front end comprising ECRIS, rfq- and IH-structure is cw suitable and will serve as injector for a new future sc-cw-linac.
GSI, Darmstadt
NSCL, East Lansing, Michigan
IAP, Frankfurt am Main
Heavy, highly-charged ions (HCI) with only one or few electrons are interesting systems for precision experiments as for instance tests of the theory of quantum electrodynamics (QED). To achieve high precision, kinetic energy and spatial position of the ions have to be well controlled. This is in contradiction to the production process that employs stripping of electrons at high energies by sending relativistic highly-charged ions with still many electrons through matter. In order to match the production at 400 MeV/u with the requirements of the experiments - stored and cooled HCI at low energy - the linear decelerator facility HITRAP has been built at the experimental storage ring (ESR) at GSI in Darmstadt. The ions are first decelerated in the ESR from 400 to 4 MeV/u, cooled and extracted. The ion beam phase spaces are then matched to an IH-structure, decelerated from 4 to 0.5 MeV/u before a 4-rod RFQ reduces the energy to 6 keV/u. Finally, the HCI are cooled in a Penning trap to 4 K. Extensive ion optical calculations were performed and in recent tests up to one million highly-charged ions have been decelerated from 400 MeV/u to 0.5 MeV/u.
ANL, Argonne
ANL Physics Division is pursuing a major upgrade of the ATLAS National User Facility. The overall project will dramatically increase the beam current available for the stable ion beam research program, increase the beam intensity for neutron-rich beams from Californium Rare Isotope Breeder Upgrade (CARIBU) and improve the intensity and purity of the existing in-flight rare isotope beam (RIB) program. The project will take place in two phases. The first phase is fully funded and focused on increasing the intensity of stable beams by a factor of 10. This will be done using a new normal conducting, CW RFQ accelerator and replacing three cryostats of split-ring resonators with a single new cryostat of high-performance quarter-wave resonators. To further increase the intensity for neutron-rich beams, we have started development of a high-efficiency charge breeder for CARIBU based on an Electron Beam Ion Source. The goal of the proposed second phase will be to increase the energies and intensities of stable beams, as well as, increase the efficiency and beam current for CARIBU and in-flight RIB beams. The focus of this paper is on innovative developments for Phase I of the project.
ANL, Argonne
A new cryomodule is being designed for the ongoing ATLAS efficiency and intensity upgrade. The cryomodule consists of 7 Quarter-Wave Resonators (QWR) with β-G=0.075 and 4 SC solenoids to replace the existing split-ring cavities. To reduce the resonator frequency jitter due to micro-phonics we choose a frequency of 72.75 MHz instead of 60.625 MHz. At 72.75 MHz, the cavity is shorter by about 20 cm. The choice of the design β was optimized based on the beam dynamics and the actual performance of ATLAS cavities. To reach a record high accelerating voltage of 2.5 MV per cavity or higher, the EM design was carefully optimized. The main goal of the optimization was to minimize the peak magnetic and electric fields while still keeping good values for the stored energy, the shunt impedance (R/Q) and the geometric factor (Rs/Q). The cavity height was also another important parameter. The optimization has lead to a final shape which is cylindrical in the bottom and conic on the top keeping a high real-estate gradient. The optimization also included the internal drift tube face angle required for beam steering correction.
NIRS, Chiba-shi
AEC, Chiba
A compact injector, consisting of the permanent-magnet ECR ion-source, the RFQ linac and the alternating-phase-focused interdigital H-mode drift-tube-linac (APF IH-DTL), was developed for an injector of medical-accelerator facilities, dedicated for the heavy-ion cancer therapy. The injector can accelerate heavy-ions having q/m=1/3 up to 4 MeV/u. Beam acceleration tests of the compact injector were successfully made at the National Institute of Radiological Sciences (NIRS), and the results of the acceleration tests proved its excellent performance*. The same design was used for the injector, constructed at the Heavy Ion Medical Center in the Gunma University. Our compact injector was recently installed in the HIMAC, and will be used as the second injector of the HIMAC. The new beam transport line for the compact injector was constructed in conjunction with the existing transport line. The entire injector system of the HIMAC accelerator complex will be presented.
* Y. Iwata, et al., Nucl. Instr. and Meth. in Phys. Res. A 572 (2009) 1007.
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
Fundación TEKNIKER, Eibar (Gipuzkoa)
The Medium Energy Beam Transport (MEBT) line for the Front End Test Stand (FETS) at Rutherford Appleton Laboratory (RAL) will transport a 60 mA, 2ms, 50 pps H- beam at 3 MeV. Its main components include a number of quadrupoles, re-bunching cavities and a fast-slow chopping system with dedicated beam dumps, as well as a diagnostics beam line. In this paper we present the design approach for the MEBT re-bunching cavities. A description is given for the proposed geometry and the main design choices are examined. In addition, the latest RF simulations results performed with 2D and 3D electromagnetic codes are presented including optimisation details and manufacturing plans.
IHEP Beijing, Beijing
Work on the Chinese Spallation Neutron Source (CSNS) has been progressing well, including successful prototyping of some of the key components of the facility. The source incorporates an H- linac, with an output energy upgradable from 81 to 250 MeV. The status of the project will be described.
INFN/LNL, Legnaro (PD)
CW RFQs requires solid design since they have to deal with design challenges and technological limitations. This talk overviews the recent performances of some of the most powerful RFQ cavities. Development, industrialisation and commissioning results of CW RFQ are describe and discussed, with recent update on two emblematic designs: IFMIF and TRASCO.
IHEP Beijing, Beijing
CIAE, Beijing
In the next two decades, China will be in period of fast development of nuclear power to meet the energy demands of the rapid economy growth and to cut down the CO2 release. Accelerator Driven System is recognized as the best option for nuclear radioactive waste transmutation. ADS long-term development roadmap has been proposed. Based on the ADS basic study in the last decade, a samll-scale ADS facility is going to be built to do experimental research on ADS system. In this paper, we will first review the previous R&D activity on ADS linac research in China, and then introduce the design of the linac in the small-scale ADS facility.
TUB, Beijing
This paper will be generally reported that a new project of the Compact Pulsed Hadron Source (CPHS) led by the Department of Engineering Physics of Tsinghua University in Beijing, China. CPHS consists of a proton linac (13MeV, 16kW, Operating frequency 325MHz, peak current 50 mA, 0.5 ms pulse width at 50 Hz), a neutron target station (a Be target, moderators and reflector), and a small-angle neutron scattering instrument, a neutron imaging/radiology station, and a proton irradiation station. The linac accelerator is the main part of this project, which including a ECR ion source. LEBT section, a RFQ accelerator, a DTL linac and a HEBT An An experimental platform for further proton applications and more neutron beam lines will be added at a later stage. Currently, fabrication of the accelerator components has begun while the neutron target station, beam lines and instruments are under design study. The initial phase of the CPHS construction is scheduled to complete in the end of 2012.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
Beam commissioning of the J-PARC linac started in November 2006 and 181 MeV acceleration was successfully achieved in January 2007. The linac had delivered beams for commissioning of accelerators and experimental facilities. Trip rates of the RFQ, however, unexpectedly increased in Autumn 2008, and that was the primary limitations of the operation days and power ramp up. We tried to recover by improvement of vacuum properties, tender conditioning and so on. By taking these measures, we can lengthen the continuous operation days and stand user operations. We ramped up the beam power from 20 kW to 120 kW for 3 GeV beam users in November 2009. This corresponds to the linac beam power of 7.2 kW and the linac has delivered beams at this power since then without significant troubles. And also we successfully demonstrated 300 kW at 3 GeV for 1 hour in December. We present the performance and operation experiences of the J-PARC linac.
BNL, Upton, Long Island, New York
RLNR, Tokyo
It is commonly preferred to have a short distance between an RFQ and a consequent DTL, however many devices has to be accommodated within a limited space. Our new medium energy beam transport line for proton beam is categorized as one of the severest cases. High field gradient quadrupoles (65 Tm) and newly designed steering magnets (6.5 mm in length) were fabricated considering the cross-talk effects. Also a new half wave length 200 MHz buncher is being studied. In the conference, the electro-magnetic field designs and the measured result will be discussed.
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 status of the FETS will be given and experimental results from the commissioning of LEBT and ion source 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 more than a factor of 2. The results from measurements will be compared with numerical simulations of the particle dynamics from the ion source to the end of the MEBT and the results discussed in respect to further work.
BNL, Upton, Long Island, New York
IAP, Frankfurt am Main
Kyushu University, Hakozaki
The EBIS based preinjector for RHIC is now being commissioned. The Linac was delivered in April 2010 and commissioning started in May, 2010. It accelerates ions from 0.3 MeV/u to 2 MeV/u with 27 accelerating gaps, one internal quadrupole triplet, and operates at 100.625 MHz. The Linac is followed by a beam transport line to Booster which includes seven quadrupoles, two bunchers, and an achromatic bend system with resolution of 500 at 2 MeV/u to select the required charge state. Diagnostics include a pepperpot emittance probe, phase probes , fast Faraday cup, adjustable slits, three sets of multiwire profile monitors, three current transformers, two Faraday cups, and two beam stops. This contribution will report results of linac tuning and cold measurements, and commissioning of the Linac and high energy transport line with helium and gold beams.
BNL, Upton, Long Island, New York
Kyushu University, Hakozaki
IAP, Frankfurt am Main
Department of Energy Sciences, Tokyo Institute of Technology, Yokohama
The EBIS based preinjector for the RHIC is now being commissioned. During the step-wise commissioning of the preinjector from January 2009 to June 2010, the RFQ was commissioned first using Test EBIS in January 2009 and then moved to its final location and commissioned again with RHIC EBIS in March 2010. The RFQ accelerates ions from 17 keV/u to 300 keV/u and operates at 100.625 MHz. The RFQ is followed by a short (81 cm) Medium Energy Beam Transport (MEBT), which consists of four quadrupoles and one buncher cavity. Temporary diagnostics for this commissioning included an emittance probe, TOF system, fast Faraday cup, and beam current measurement units. This contribution will report results of RFQ and MEBT commissioning with helium and gold beams.
RLNR, Tokyo
A new type Linac, HSC (hybrid single cavity) linac for cancer therapy, which configuration combines RFQ (Radio Frequency Quadrupole) accelerating structure and DT (Drift Tube) accelerating structure is being finished designs and simulations now. This HSC linac design had adopted advanced power-efficiency-conformation, IH (Interdigital H) structure, which acceleration efficiency is extremely high in the low-middle energy region, and had also adopted most advanced computer simulation technology to evaluate cavity electromagnetic distribution. The study purposes of this HSC linac focus to design of injector linac for synchrotron of cancer radiotherapy facilities. Here, this HSC linac has an amazing space effect because of compact size by coupled complex acceleration electrode and integrated the peripheral device which is made operation easy to handle. The size of the HSC linac is very compact and is also easy to be adopted for cancer therapy in normal hospital.
TUB, Beijing
The Compact Pulsed Hadron Source (CPHS) system has been proposed and designed by the Department of Engineering Physics of Tsinghua University in Beijing, China. It consists of an accelerator front-end'a high-intensity ion source, a 3 MeV radiofrequency quadrupole linac (RFQ), and a 13 MeV drift-tube linac (DTL), a neutron target station, and some experimental stations. In our design, both RFQ and DTL share a single klystron which is capable of 2.5 MW peak RF power and a 3.33% duty factor. The 325 MHz klystron contains a modulating anode and has a 100 kW average output power. Portions of the RF system, such as pulsed high voltage power source, modulator, crowbar protection and RF transmission system are all presented in details in this paper.
IMP, Lanzhou
PKU/IHIP, Beijing
Heavy Ion Research Facility at Lanzhou (HIRFL) consists of two cyclotrons (SFC and SSC), one synchrotron (CSRm), and one storage ring (CSRe). The two cyclotrons are in series as the injector of the synchrotron. An additional LINAC injector for SSC is considered to increase the beam time at targets. The new injector consists of an RFQ and four IH-DTL tanks. A pre-buncher in the front of RFQ is 13 MHz to match the RF frequency of SSC. The LINAC can operate in two modes. In the first mode, the middle-mass ions output with energy of 0.54 MeV/u, and then SSC accelerates them up to the energy of 5.62 MeV/u. The beam is used to do the Super Heavy Elements (SHE) experiments. In the second mode, the very heavy ions output with energy of 0.97 MeV/u, and then SSC accelerates them up to energy of 10.06 MeV/u. The beam is injected into CSRm after stripped. Code LINREV and DAKOTA are used to design and optimize the acceleration structures of DTLs. The energy spread less than ±0.5% and bunch length less than 2.6 ns are achieved at the exit of the last tank. These can match the ideal acceptance of SSC. A simulation from LEBT to exit of DTL is done by Beampath to benchmark the design.
* All authors belong to PKU-IMP RF LINAC Research Center for Heavy Ions.
IAP, Frankfurt am Main
Abstract A short RFQ prototype was built for tests of high power RFQ structures. We will study thermal effects and determine critical points of the design. HF-Simulations with CST Microwave Studio and measurements were done. The RF-Tests with continues power of 20 kW/m were finished successfully. Simulations of thermal effects with ALGOR are on focus now. First results and the status of the project will be presented.
IAP, Frankfurt am Main
NTG, Gelnhausen
The IH-type RFQ for the MAFF project at the LMU in Munich was operated at a beam test stand at the IAP in Frankfurt. It is the second IH-RFQ after the HIS at GSI and it has been designed to accelerate rare isotope beams (RIBs) with mass to charge ratios A/q up to 6.3 from 3 keV/u to 300 keV/u at an operating frequency of 101.28 MHz with an electrode voltage of 60 kV. Experimental results such as shunt impedance, energy spectrum and transmission will be presented.
IAP, Frankfurt am Main
GSI, Darmstadt
A new CW-RFQ has been built for the upgrade of the HLI (High Charge State Injector) of GSI for operating with a 28GHz-ECR-Ion source and simultaneous increase of the beam duty cycle from 25 % now to 100 %. The new HLI 4-rod RFQ will accelerate charged ions from 4 keV/u to 300 keV/u for the injection into the IH-structure. High beam transmission, a small energy spread and small transverse emittance growth and good input matching are design goals. Properties of this CW-RFQ, status of project and first measurements will be presented.
CERN, Geneva
CEA, Gif-sur-Yvette
The construction of Linac4, the new 160 MeV CERN H- injector, has started with the goal of improving the LHC injection chain from 2015 with a new higher energy linac. The low energy front end of Linac4 is based on a 352 MHz, 3-m long Radiofrequency Quadrupole (RFQ) accelerator. The RFQ accelerates the 70 mA, 45 keV H- beam from the RF source to the energy of 3 MeV. The fabrication of the RFQ has started at CERN in 2009 and is presently in progress, aiming at the completion of the full structure by early 2011. The RFQ consists of three modules, one meter each; the fabrication alternates machining phases and stress relief cycles, for copper stabilization. Two brazing steps are required: one to assemble the four parts composing a module and a second one to install the stainless steel flanges. In order to monitor that the tight mechanical and alignment budget is not exceeded, metrology measurements at the CERN workshop and RF bead-pull measurements are performed during the fabrication process. In this paper we report results obtained during the machining and the assembly of the first two modules of the Linac4 RFQ and data produced by RF measurements performed during their fabrication.
IMP, Lanzhou
IAP, Frankfurt am Main
BNL, Upton, Long Island, New York
A compact RFQ for carbon ion beam from a Laser-ion souce is being tested in IMP, Lanzhou. It is the first example of LINAC structures for IMP. Testing schemes and first results are presented.
IMP, Lanzhou
IAP, Frankfurt am Main
BNL, Upton, Long Island, New York
A RFQ has been designed and built for research of direct plasma injection scheme (DPIS), which can provide high current and highly charged beams. Because of the strong space charge forces of beam from laser ion source, the beam dynamics design of the RFQ was carried out with a new code LINACSrfq which can treat space charge effectively due to equipartitioning design strategy. Another feature of the RFQ is its high energy gain in two-meter long which will be described in detail. Construction of the RFQ cavity and the 100MHz/250kW amplifier has been completed and ready for test. A laser ion source is being tested. The assembling of the whole system including the ion source, the RFQ, the beam analyzing and diagnostic system is being done. Preliminary test results will be presented.
Soreq NRC, Yavne
The SARAF 4-rod RFQ is operating at 176 MHz, designed to bunch and accelerate a 4 mA CW deuteron/proton beam to 1.5 MeV/u. The electrodes voltage for accelerating deuterons is 65 kV, a field of 22 MV/m. The RFQ injected power is induced by a loop coupler. The power needed to achieve this voltage is 250 kW, distributed along the 3.8 m RFQ length. This power density is approximately 3 times larger than that achieved in other 4-rod RFQs. At high power, local high surface currents in the RFQ might cause overheating which will lead to out-gassing and in turn to sparking. We used CST MWS to simulate the RF currents and fields in a 3D detailed model of the SARAF RFQ. The correct eigenmode was reproduced and both Qe and Qo are consistent with the measured values. The heat load generated by the simulated surface currents at critical areas along the RFQ was the input for thermal analysis using Ansys. Detailed results reproduced the experimental observation of several overheated regions in the RFQ, including the end flanges and the plungers. Further results predicted overheating at different regions which were subsequently measured and are now being improved by additional cooling.
TUB, Beijing
LANL, Los Alamos, New Mexico
NUCTECH, Beijing
CERN, Geneva
We present, in this paper, the physics and mechanical design of a Radio Frequency Quadrupole (RFQ) accelerator for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. The 3-meter-long RFQ will accelerate protons from 50 keV to 3 MeV at an RF frequency of 325 MHz. In the physics design we have programmed the inter-vane voltage as a function of beam velocity, to optimize the performance of the RFQ, by tailoring the cavity cross section and vane-tip geometry as a function of longitudinal position while limiting the peak surface electric field to 1.8 Kilpatrick. There will be no Medium-Energy-Beam-Transport (MEBT) following the RFQ. The focusing at the high energy end of the RFQ and at the entrance of the DTL have been tailored to provide continuous restoring forces independent of the beam current. In simulations of the proton beam in the RFQ, using the code PARMTEQM, we observe transmission exceeding 97%. The RFQ is mechanically separated into three sections to facilitate machining and brazing. We have machined a test section and the final RFQ accelerator is now under construction. We will describe the status of the RFQ system in this paper.
* K. R. Crandall et al., RFQ Design Codes, LA-UR-96-1836.
ORNL, Oak Ridge, Tennessee
University of Tennessee, Knoxville, Tennessee
In radio frequency quadrupole (RFQ) structures, the fundamental quadrupole mode is used for focusing and acceleration of ion particles. The fields are maintained to have negligible interference with other unwanted modes of the structure using mode suppressors of different types especially in vane type RFQs that require dipole mode separation. The field distribution on the beam axis is usually measured and referenced using multiple loop-type magnetic probe antennas on the wall along the structure. Since the structures are equipped with many slug tuners on the outer wall for correction of fields, the tuner-probe interference can be a concern. In order to investigate the mode separation properties of the commonly used mode suppressors and the accuracies in field distribution with respect to localized perturbation due to the tuners, a systematic 3D simulation was carried out using a full-scale model of the SNS RFQ.
Fermilab, Batavia
The Fermilab High Intensity Neutrino Source program has built and commissioned a pulsed 325 MHz RFQ. The RFQ has successfully accelerated a proton beam at the design RF power. Experiences encountered during RFQ conditioning, including the symptoms and cause of a run-away detuning problem, and the first beam results are reported.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
KEK, Ibaraki
The J-PARC RFQ (length 3.1m, 4-vane type, 324 MHz) accelerates a negative hydrogen beam from 0.05MeV to 3MeV toward the following DTL. We started the preparation of a new RFQ as a backup machine. The new cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes. A numerical controlled machining with a conventional ball-end-mill has been chosen for the vane modulation cutting instead of the wheel shape cutter. In this presentation we will report the machining procedure, the results of the vane machining, RF properties, and some topics during the fabrication.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
KEK, Ibaraki
The J-PARC RFQ (length 3.1m, 4-vane type, 324 MHz) accelerates a negative hydrogen beam from 0.05MeV to 3MeV toward the following DTL. We started the preparation of a new RFQ as a backup machine. The new cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes. A one-step vacuum brazing of a unit tank has been chosen to unite these four vanes together with the flanges and ports. In this presentation we will report the results of the vacuum brazing with the dimension accuracy and an RF property.
LBNL, Berkeley, California
Project X is a proposed multi-MW proton facility at Fermi National Accelerator Laboratory. It is the key element for future accelerator complex development intended to support world-leading High Energy Physics (HEP) programs. The Project X front-end would consist of H- ion source(s), a low-energy beam transport (LEBT), radio-frequency quadrupole (RFQ) accelerator(s), and a medium-energy beam transport (MEBT). To support current and future HEP experiments at Fermilab, a CW RFQ is required. One of the chosen RFQ designs has a resonant frequency at 325 MHz. The RFQ provides bunching of the 10 mA H- beam with acceleration up to 2.5 MeV and wall power losses of less than 250 kW. LBNL is currently developing the early designs for various components in the Project X front-end. The RFQ design concept and the preliminary RF and thermal analyses are presented here.
KAERI, Daejon
A Radio Frequency Quadrupole (RFQ) has being desinged for the post-acceleration of radio isotope beams from a radio isotope beam production system such as an isotpe separation on line (ISOL) or an in-flight separation. For simple and efficient beam acceleration, a chrage breeding system such as an electron cyclotron resonance ion source (ECRIS) or electron beam ion source (EBIS) The RFQ will operate at a resonant frequency of 70MHz at cw mode, and accelerate the beams to 300keV/nucleon. In the conference we will present the design of the RFQ.
Siemens Med, Erlangen
Siemens DK, Jyllinge
Siemens is currently preparing, installing and commissioning three IONTRIS particle therapy accelerator systems - two in Germany, in Marburg and Kiel, and one in Shanghai, China. Siemens IONTRIS is based on a synchrotron to accelerate protons and carbon ions for clinical applications up to 250 MeV resp. 430 MeV/u. The injector part consists of an RFQ to accelerate protons and light ions up to 400 keV/u followed by an IH-cavity, wherein the particles achieve 7 MeV/u. The results of the commissioning of the RFQ in the test facility in Denmark will be presented.
*Particle Therapy is a work in progress and requires country-specific regulatory approval prior to clinical use.
INFN/LNL, Legnaro (PD)
INFN- Sez. di Padova, Padova
In order to attain the stringent goals that assure the required performances of the IFMIF-EVEDA RFQ in terms of field uniformity, Q-value and RF-induced heat removal capability, the study of the 3D details of the cavity is particularly important. In this paper the main issues regarding the design of the slug tuners, cavity ends and vacuum grids are addressed, as well as the related optimization procedure.
INFN/LNL, Legnaro (PD)
The TRASCO RFQ will accelerate the 40 mA cw proton beam from the ion source to the energy of 5 MeV, for the production of intense neutron fluxes for interdisciplinary applications. The RFQ is composed of six modules of 1.2 m each, assembled by means of ultra high vacuum flanges. The structure is made of OFE copper and is fully brazed. RFQ modules were manufactured in CINEL Scientific Instruments S.r.l. while chemical treatments and brazing were done at CERN. This paper covers the brazing results of the last four modules and low power tests performed for preparation to the high power test of the first electromagnetic segment.
INFN- Sez. di Padova, Padova
INFN/LNL, Legnaro (PD)
In the framework of the IFMIF/EVEDA project, the RFQ is a 9.8 m long cavity, with very challenging mechanicals specifications. In the base line design, the accelerator tank is composed of 18 modules that are flanged together. An RFQ prototype, composed of 2 modules with a reduced length, aimed at testing all the mechanical construction procedure is under construction. In this paper, the thermo-mechanical study by means of 2D thermo structural and 3D fluid-thermal-structural simulations will be described. The measurements made with a cooling water circuit on a part of the RFQ prototype and the comparison with fluid thermal simulation will be reported.
ANL, Argonne
An integral part of the ongoing ATLAS efficiency and intensity upgrade is an RFQ to replace the first section of the existing injector. The proposed RFQ is 3.8 m long made of 106 cells with 30 keV/u input energy and 260 keV/u output energy. The RFQ was designed using the DesRFQ code which produces a file consisting of the length, modulation and the 8 coefficients of the 8-term potential for every cell. To independently check the design we created full 3D models of the RFQ including cell modulation in both Micro-Wave Studio (MWS) and Electro-Magnetic Studio (EMS). The MWS model was used to verify the phasing and energy gain along the RFQ using particle tracking and the EMS model was used to extract the electric field cell by cell assuming the electrostatic approximation. A very good agreement was obtained between the full 3D model and the 8-term potential description in TRACK. In addition to the standard sinusoidal vane profile we studied the option of converting the cells with maximum modulation (~ 40 cells) into trapezoidal cells. The output energy was increased from 260 keV/u to ~ 300 keV/u with minimal change to beam dynamics. This option is the final RFQ design.
RAS/INR, Moscow
Due to dispersion properties 4-vane RFQ cavity without resonant coupling is a thermally unstable structure. With deterioration of balance for local detuning there is a possibility for runaway in the field distribution and related thermal effects. It can results, in principle, in irreversible plastic deformations and cavity frequency shift. Both the increment and the threshold of instability are proportional to the average dissipated RF power. This possibility is more probable for long RFQ cavities. Also particularities for the cavity ends design are important. Some general features of this effect are discussed qualitatively and illustrated with simulations.
RIKEN Nishina Center, Wako
SHI, Tokyo
A new linac injector, which will be exclusively used for the RIKEN RI-Beam Factory, has been constructed to increase the beam intensity of very heavy ions such as xenon and uranium. The injector system consists of a superconducting ECR ion source, RFQ linac, three DTLs, and beam transport system including strong quarupole magnets and beam bunchers. Two DTL resonators were newly designed while existing devices including the RFQ* were modified to the other resonators. Direct coupling scheme was adopted for the rf-sytems of the DTLs, where the design study was successfully perfomed by using the MWS code. This paper focuses on the design procedure of the DTLs and RFQ as well as the results of their low and high power tests.
*H. Fujisawa, Nucl. Instrum. and Methods A345 (1994) 23-42.
TUB, Beijing
TechSource, Santa Fe, New Mexico
NUCTECH, Beijing
CIAE, Beijing
CERN, Geneva
IHEP Beijing, Beijing
The CPHS project in Tsinghua University plans to construct a 13 MeV linear accelerator to deliver a pulsed proton beam having an average beam current of 2.5 mA. A Drift Tube Linac (DTL), following a Radio Frequency Quadrupole accelerator(RFQ), will accelerate protons from 3 to 13MeV. The accelerating field and phase will be ramped to match the longitudinal restoring forces at the end of the RFQ. Likewise, the transverse focusing forces, provided by permanent-magnet quadrupole lenses (PMQs) will be programmed to match the transverse restoring forces at the end of the RFQ to avoid missmatch and avoid parametric resonances. We will present the main physics design parameters of CPHS DTL and describe the properties of the resonant cavity. We plan to apply electron beam welding technology exclusively in the fabrication of the drift tubes and will present the test results from our engineering prototyping program.
ORNL, Oak Ridge, Tennessee
We present practical aspects of measuring beam profiles and applications using the profile data. Standard applications include (RMS) beam size calculation, Courant-Snyder parameter calculation, and beam matching. Each application becomes increasingly model dependant relying upon results of the preceding application. Because of the cascade of interdependence, of obvious concern is measurement error which propagates throughout the calculations. Also important is the accuracy of the beam model used to make calculations from measurement results; doubly so for matching where the model both estimates Courant-Snyder parameters and predicts new magnet strengths. Not as obvious are complications introduced by the long pulse nature of the SNS linac. Currently, we can sample the beam only through a 50 microsecond window along a macro pulse lasting up to 1 millisecond. Consequently the measurements available are not necessarily representative of the whole beam. Presented are quantitative results on measurement error, model accuracy, and sampling location, how these quantities vary along the linac, and the ramifications on matching techniques.
Soreq NRC, Yavne
The SARAF accelerator is designed to accelerate both deuteron and proton beams up to 40 MeV. Phase I of SARAF consists of a a 4-rod RFQ (1.5 MeV/u) and a superconducting module housing 6 half-wave resonators and 3 superconducting solenoids (4-5 MeV). The ions energy and energy spread were measured using the Rutherford scattering technique . This technique is used to tune the cavities to the desired amplitude and phase. The downstream HWR is used as a buncher and the beam energy spread as function of the bunching RF voltage is applied to estimate the longitudinal emittance. In this work, we present a longitudinal emittance measurement algorithm, which is based on the bunch energy spread as a function of the buncher's amplitude, similar to the standard algorithm that uses the bunches' temporal spread. The tuning and measured longitudinal parameters are in qualitative agreement with the predicted beam dynamics simulation.
TRIUMF, Vancouver
The post acceleration section of the ISAC radioactive ion beam (RIB) facility is composed of a radio frequency quadrupole (RFQ) followed by a drift tube linac (DTL), both room temperature machines, that serve a medium energy experimental area up to 1.8 MeV/u, and a superconducting linac (SCLINAC) that serves a high energy experimental area. This SCLINAC, composed of forty quarter wave resonators housed in eight cryomodules, is capable of a total accelerating voltage of circa 40 MV. Since each cavity is phased independently at the maximum operational voltage, the final energy depends on the mass to charge ratio of the accelerated species. In order to deliver energies higher than 5 MeV/u we need to monitor the beam current as mandated by our operating license. The current monitor system (CMS) is composed of two non intercepting and one partially intercepting monitor. The signals from these three monitors are processed in a single control system that provides a go signal to the Safety system enabling beam delivery. The CMS system allows to exploit the SCLINAC to its full potential. In this paper we will present both hardware configuration and software control of the CMS.
Soreq NRC, Yavne
NTG Neue Technologien GmbH & Co KG, Gelnhausen
RI Research Instruments GmbH, Bergisch Gladbach
Phase I of the Soreq Applied Research Accelerator Facility, SARAF, has been installed and is currently being commissioned at Soreq NRC [1]. According to the Phase I design, SARAF should yield 2 mA proton and deuteron beams at energies up to 4 and 5 MeV, respectively. The status of the main Phase I components is reported. We further present beam commissioning results, which include acceleration of a 1 mA CW proton beam up to 3 MeV. Further improvements in the facility in order to achieve the desired performance are discussed.
CERN, Geneva
Linac4 is a 160 MeV normal-conducting H- linear accelerator which is being built at CERN in the frame of a program for increasing the luminosity of the LHC. The project started in 2008 and delivery of beam to the CERN accelerator chain is foreseen from early 2015. The new linac will be housed in an underground tunnel close to the present Linac2; a surface building will house RF and other infrastructure. The civil engineering work started in October 2008 will be soon completed. Installation of the infrastructure will take place in 2011, and from 2012 will be installed the main machine elements. The ion source is presently operational on a test stand, where it will be followed in 2011 by a 3 MeV RFQ under construction in the CERN workshops. Prototypes of the three different types of accelerating structures have been tested; construction of the 22 accelerating cavities has started, supported by a network of agreements with external laboratories and institutions. Commissioning will take place in stages, starting from January 2013. Starting in March 2014 is foreseen a six-month reliability run, in preparation for its role as the new source of particles for the CERN complex.
CEA, Gif-sur-Yvette
New PIC ray-tracing methods allows to design and simulate the transport of high intensity proton, H- and deuteron beam in the LEBT systems of future facilities like FAIR Proton Linac or IFMIF-EVADA and SPIRAL2 deuteron linacs. These techniques enable a precise prediction of the effect of residual gas ionisation and the consequent neutralisation of the large beam space charge on the beam emittances.
Fermilab, Batavia
The intensity frontier, having been identified as one leg of the future of particle physics, can be meet by the development of a multi-GeV high-intensity linac. In order to address the low-energy needs of such an accelerator, Fermilab started the High Intensity Neutrino Source (HINS) project. HINS is a research project to address accelerator physics and technology questions for a new concept, low-energy, high-intensity, long pulse H- superconducting linac. The development of such an accelerator puts strict requirements on beam diagnostics. This paper will present beam measurement results of the HINS ion source and 2.5 MeV RFQ as well as discuss the role of HINS as a test facility for the development of future beam diagnostic instrumentation required for the intensity frontier.
CERN, Geneva
TechSource, Santa Fe, New Mexico
Linac4 is a new 160 MeV, 40 mA average beam current H- accelerator which will be the source of particles for all proton accelerators at CERN as from 2015. Construction started in October 2008, and beam commissioning of the 3MeV frontend is scheduled for early next year. A baseline design of the linac beam dynamics was completed 2 years ago and validated by a systematic campaign of transverse and longitudinal error studies to assess tolerance limits and machine activation levels. Recent studies have been mainly focused on optimising this design to achieve both a smoother performance for nominal beam conditions and to gain operational flexibility for non-nominal scenarios. These include a review of the chopper beam dynamics design, a re-definition of the DTL and CCDTL inter-tank regions and a study of operational schemes for reduced beam currents (either permanent or in pulse-to-pulse mode). These studies have been carried out in parallel to first specifications for a beam commissioning strategy of the linac and its low-energy front-end.
Fermilab, Batavia
Front end of a CW linac of the Project X contains a H- source, an RFQ, a medium energy transport line with the beam chopper, and a SC low-beta linac that accelerates H- from 2.5 MeV to 160 MeV. SC Single ' spoke Resonators (SSR) will be used in the linac, because Fermilab already successfully developed and tested a SSR for beta 0.21. Two manufactured cavities achieve 2-3 times more than design accelerating gradients. One of these cavities completely dressed, e.g. welded to helium vessel with integrated slow and fast tuners, and tested in CW and pulse regimes. Successful tests of beta=0.21 SSR give us a confidence to use this type of cavity for low beta (0.117) and for high- beta (0.4) as well. Both types of these cavities are under development. In present report the basic constrains, parameters, electromagnetic and mechanical design for all the three SSR cavities, and first test results of beta=0.21 SSR are presented.
IHEP Beijing, Beijing
Institute of High Energy Physics, CAS, Bejing
China Spallation Neutron Source (CSNS) is determined to be constructed in Dongguan, Guangdong province of south China. Now its design and R&D are in progress in IHEP, Beijing. The 324 MHz rf linac is designed with beam energy of 81 MeV and a peak current of 30 mA. In the klystron gallery, five klystron power sources will be used to power the RFQ and the four DTL tanks, and three solid state RF amplifiers will drive two MEBT bunchers and a LRBT debuncher. Now we have already made some progress with some key technologies for linac RF system. The digital low level RF control prototype was already developed and successfully applied in beam commissioning of the ADS (Accelerator Driven Sub-critical system) 3.5MeV RFQ accelerator at peak beam 44.5mA, beam duty 7.15%. A proposed new type of power supply, 100Hz ac series resonance high voltage power supply, passed acceptance test and a satisfactory test results was obtained. R&D of crowbar and modulator has gotten preliminary performance test data.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
KEK, Ibaraki
LBNL, Berkeley, California
For the beam current upgrade of the J-PARC linac, a new RFQ (RFQ III)is developing. The peak beam current of RFQ III is 50mA. To increase the peak current from the existing RFQ (RFQ I), the longitudinal and/or transverse emittances are expected to be increased. However, the increase of the longitudinal emittance will affect the performance of the RF chopper system. In this paper, detailed simulations of the RF chopper system are described and the requirement for the longitudinal emittance of the RFQ is clarified.
IAP, Frankfurt am Main
For the development of high energy and high duty cycle RFQs accurate particle dynamic simulation tools are important for optimizing designs, especially in high current applications. To describe the external fields in RFQs as well as the internal space charge fields with image effect, the Poisson equation has to be solved taking the boundary conditions into account. In PteqHI a multigrid Poisson solver is used to solve the Poisson equation. This method will be described and compared to analytic solutions for the Two-term-potential to verify the answer of the Poisson solver.
UMAN, Manchester
CERN, Geneva
The superconducting High Intensity and Energy (HIE) ISOLDE linac will replace most of the existing accelerating infrastructure of the Radioactive ion beam EXperiment (REX) at CERN, however, the 101.28 MHz RFQ and 5 MV IH cavity will remain in the role of injector for the upgrade, boosting the beam up to an energy of 1.2 MeV/u. We present the results of a beam dynamics investigation of the injector focused most critically on matching the longitudinal beam parameters from the RFQ to the SC machine, which is complicated largely by the IH cavity employing a Combined Zero Degree* (KONUS) beam dynamics design. The longitudinal beam parameters at the RFQ are reconstructed from measurement using the three-gradient method and combined with beam dynamics measurements and simulations of the IH structure to design the matching section for the SC linac.
*Ratzinger, U., "The IH-structure and its capability to accelerate high current beams," Particle Accelerator Conference, 1991
Soreq NRC, Yavne
Design of ion linacs with ion currents of several milli-amps necessitates detailed simulations of beam loss. At high intensities, even a small amount of beam loss can result in significant radio-activation of the linac components. Particle loss can result from longitudinal tails created in the bunching and pre-accelerating process, whereas strong transverse focusing and collimation limit the development of a transverse tail. In modern RF ion linacs, bunching and pre-acceleration take place in a radio frequency quadrupole (RFQ). We present a new approach for beam loss calculations that places emphasis on the tails of the particle distributions. This scheme is used for simulating the SARAF proton/deuteron linac, a 176 MHz complex designed to operate in CW mode at 4 mA beam current. We describe implementation of a RFQ accelerating element in the GPT 3D simulation code. We discuss our scheme for highlighting the tails of the particle distributions generated by the RFQ. These distributions are used as input to simulations of the RF superconducting linac, where subsequent particle loss is calculated. This technique allows us to increase beam loss statistics by a significant factor.
TUB, Beijing
IMP, Lanzhou
Responding to the demand of accelerator front inject system of the Compact Pulsed Hadron Source (CPHS) in Tsinghua university in 2009, an electron cyclotron resonance (ECR) proton source (2.45 GHz, 1.5 KW) and a low-energy-beam-transport (LEBT) system are designed and manufacted. In this source, the H2 plasma is restricted by an axial magnetic field shaped by the source body produced by an all-permanent-magnet design (NdFeB rings). The 50-keV pulsed proton beam (50 Hz/0.5 ms) extracted by a four-electrode extraction system from the proton source passes through the LEBT system (1283 mm long), which is consist of two solenoid lens, two steering magnets and a cone configuration optically matches to the RFQ where the Twiss parameters α=1.354, β=7.731. The beam with 97% space charge neutralization rate has been simulated at 100 mA, 150 mm.mrad RFQ output current by Trace-3D and PBGUN. In this study, we describe the design of the proton source and LEBT technical systems along with intended operation.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
J-PARC, KEK & JAEA, Ibaraki-ken
A cesium-free negative hydrogen ion source driven with a LaB6 filament is being operated for J-PARC. The beam commissioning of J-PARC accelerators started in November 2006. As of April 2010, there have been 32 beam commissioning or supply runs. In these runs, the ion source has been successfully operated in two different modes such as low current mode of 5 mA and high current mode of 30 mA. According to the task of the run, one of the two modes was selected. However, the beam current has been restricted to less than 15 mA for the stable operation of the RFQ linac which has serious discharge problem from September 2008. The beam run is performed during 4-5 weeks cycles, which consisted of a 3-4 weeks beam run and 4 days down-period interval. At the recent beam run, approximately 700 hours continuous operation was achieved, which is satisfied with the requirement of the ion source lifetime for the J-PARC first stage. At every runs, the beam interruption time due to the ion source failure is several hours, which correspond to the ion source availability of 99 %.
BNL, Upton, Long Island, New York
Kyushu University, Hakozaki
IAP, Frankfurt am Main
This talk will present commissioning of a new heavy ion pre-injector at Brookhaven National Laboratory. This preinjector uses an Electron Beam Ion Source (EBIS), and an RFQ and IH Linac, both operating at 100.625 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.