ORNL, Oak Ridge, Tennessee
This talk will present the stutus of SNS operation at 1MW and plan beyond it.
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.
IPN, Orsay
GANIL, Caen
IN2P3 IPNL, Villeurbanne
LPSC, Grenoble
CEA, Gif-sur-Yvette
The SPIRAL-2 superconducting linac driver, which aims at delivering 5 mA, 40 MeV deuterons and up to 1 mA, 14.5 A.MeV q/A=1/3 heavy ions, has now entered its construction phase in GANIL (Caen, France). The linac is composed of two injectors feeding one single RFQ, followed by a superconducting section based on 88 MHz independently-phased quarter-wave cavities with room-temperature focusing elements. The first stages of the injectors have been fully built and are now operational. They have been partly commissioned with beam in Grenoble and Saclay in 2010. This paper describes the results obtained so far in this context.
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
IKP, Mainz
IAP, Frankfurt am Main
HIM, Mainz
GSI applied for a new superconducting (sc) cw-LINAC in parallel to the existing UNILAC. Such a machine is highly desirable with respect to the progress in the field of Superheavy Elements (SHE) for example. The UNILAC at GSI is limited in providing a proper beam for SHE and in fulfilling the requirements for FAIR simultaneously. A sc CH-structure is the key component of the proposed efficient and compact linac. In first vertical rf-tests at the Institute of Applied Physics (IAP) maximum gradients up to 7 MV/m were achieved. The cavities for the cw-LINAC should be operated at 217 MHz providing gradients of about 5.1 MV/m at a total length of minimum 0.6 m . In a first step a prototype of such a sc cw-LINAC as a demonstrator is financed by the Helmholtz Institute Mainz (HIM). The demonstrator is the first section of the proposed cw-LINAC consisting of a sc CH-cavity embedded by two sc solenoids. The aim is a full performance test of the demonstrator with beam at the GSI high charge injector (HLI) in 2013. Presently the tendering of the solenoids, the cavity, the cryostat and the rf-amplifier is in preparation.
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.
GSI, Darmstadt
A low current high duty factor U10+-beam from the Penning Ion Source as well as a high current low duty factor U4+-beam from a MeVVa source were used for machine investigations in the GSI-UNILAC and synchrotron (SIS18). Carbon stripper foils (20, 40 and 50 ug/cm2) were mounted in the gas stripper section at 1.4 MeV/u to provide for highly charged uranium ions (40+) to be delivered to the SIS18 for life time beam measurements. High current tests were performed to check the durability of the carbon foils. No measurable variation of the stripped low and high current beam in the poststripper DTL could be detected during the life time of the foils. An U40+-beam current of up to 1.0·10+11 particles per 100mues could be reached in the transfer line to the SIS18. This paper will report on the investigations of stripper foils with different thickness. Additionally long time observation of all relevant beam parameters (transverse emittance, energy spread and energy loss, bunch shape, beam transmission up to the SIS-injection) are presented.
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.
NSCL, East Lansing, Michigan
FRIB, East Lansing, Michigan
The primary purpose of the Facility for Rare Isotope Beams (FRIB) is to produce and to do fundamental research with rare isotopes. The rare isotope production will be accomplished using a heavy ion cw linac to provide a stable isotope beam (protons through uranium) at high power (up to 400 kW) and high energy (>200 MeV/u) on a particle fragmentation production target. The rare isotopes will be produced in quantities sufficient to support world-leading research by using particle fragmentation of stable beams. This will include research pertaining to the properties of nuclei (nuclear structure), the nuclear processes in the universe and tests of fundamental symmetries. Societal applications and benefits may include bio-medicine, energy, material sciences and national security. The overall facility status and plans will be discussed with a focus on the accelerator system.
NSCL, East Lansing, Michigan
FRIB, East Lansing, Michigan
The Facility for Rare Isotope Beams (FRIB) will accelerate stable beams of heavy ions to > 200 MeV/u with beam powers of up to 400 kW onto an in-flight fragmentation target to produce rare isotopes. The accelerator system will include a room-temperature front end, a double-folded superconducting driver linac, and a beam delivery system. The front end will include superconducting ECR ion sources, a beam bunching system and a radio frequency quadrupole. The driver linac will include three acceleration segments using superconducting quarter-wave and half-wave cavities with frequencies of 80.5 and 322 MHz, and two 180 degree folding systems to minimize the cost of conventional construction. Charge-stripping and multi-charge-state beam acceleration will be used for the heavier ions to increase acceleration efficiency. The beam delivery system will transport accelerated stable beams to the in-flight fragmentation target. End-to-end beam simulations with errors have been performed to evaluate the performance of the driver linac. We will discuss recent progress in the accelerator design and the beam dynamics studies for the baseline accelerator system.
IAP, Frankfurt am Main
GSI, Darmstadt
The search for Super-Heavy Elements (SHE) is one of the frontiers in nuclear physics. By trend the production cross sections decrease significantly for larger proton numbers and heavier nuclei, respectively. To limit the required beam time it is necessary to use the highest available intensity. This prefers cw operation and the use of superconducting cavities. A cw operated superconducting linac using CH-cavities at GSI has been designed. As front end the existing 108 MHz High Charge Injector (HLI) will be used which is presently being upgraded for cw operation. The superconducting part of the linac covers the energy between 1.4 AMeV and 7.5 AMeV. It consists of 9 multi-cell CH-cavities operated at 217 MHz. Each cavity is optimized for a specific particle velocity but without beta profile. Above 3.5 AMeV the linac is fully energy variable. The first superconducting CH-cavity is already under construction and will be tested with beam delivered by the HLI. The talk covers the development of the prototypes and the overall design including beam dynamics issues.
HIT, Heidelberg
The Heidelberg Ion Beam Therapy Centre (HIT) is the only medical facility in Europe for cancer treatment with protons and carbon ions. To broaden the range of available ion species towards helium the low energy beam transport (LEBT) will be extended by a third ion source and the associated spectrometer section. Following a novel ion optical approach the LEBT-branch has been redesigned. A dedicated test bench will be used to commission and validate the new design prior to its integration into the medical accelerator. In its final stage the test bench will comprise an ECR-ion source, a LEBT and an RFQ with diagnostics line. It opens up the unique opportunity to perform comprehensive investigations not only of the ion source but also of other devices like the RFQ which have been optimised in the frame of the LINAC upgrade. Here, particular emphasis will be placed on the new design of the analyser dipole and the macro pulse chopper. Furthermore results of beam optical simulations and first measurement results will be presented.
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.
KEK, Ibaraki
CERN, Geneva
Several types of X-band high power loads developed for several tens of MW range were designed, fabricated and used for high power tests at X-band facility of KEK. Some of them have been used for many years and some show possible deterioration of RF performance. Recently revised-design loads were made by CERN and the high power evaluation was performed at KEK. In this paper, the main requirements are recalled, together with the design features. The high power test results are analysed and presented.
IAP, Frankfurt am Main
Space charge lenses use a confined electron cloud for the focusing of ion beams. Due to the electric space charge field, focusing is independent of the particle mass. For this reason the application of the space charge lens especially in the field of heavy ion beams is advantageous. Moreover, the trapped non neutral plasma cloud compensates the space charge forces of the ion beam. The focusing strength is given by the confined electron density whereas the density distribution influences the mapping quality of the space charge lens. An important parameter for the focusing capability of the space charge lens is besides the homogeneous electron distribution a high electron density. In ongoing theoretical and experimental work methods have been developed to determine the most important parameters like electron temperature and electron density distribution for an optimized lens design. Based on the experimental results a new space charge lens has been designed to focus low energy heavy ion beams like 2,4 AkeV U4+ at the low energy transport section into the GSI High Current Injector. Experimental results will be presented and compared with numerical simulations.
*W. Barth, "THE INJECTOR SYSTEMS OF THE FAIR PROJECT", LINAC08, Victoria, BC, Canada
RIKEN Nishina Center, Wako
Medium-energy high-intensity heavy-ion beams have been used for more than twenty years as powerful tools to investigate physics of unstable nuclei far from stability, in which one of the major problems is to understand the element genesis in universe. Many facilities including CERN, GANIL, GSI, MSU and RIKEN have developed their facilities to obtain much higher-intensity unstable-nuclei beams. Within these facilities, RIKEN first finished construction and commissioning of a major upgrade plan of the existing facility, RI Beam Factory, three years ago, in which the world-first superconducting ring cyclotron is pushing the limit of energy for heavy-ion cyclotrons. On the other hand, the FAIR and the FRIB project chose different strategies to obtain high-intensity heavy-ion beams, the former uses synchrotron and the latter uses superconducting linacs. The present competition with three different approaches is interesting because it will make clear that which kind of accelerator complex is most effective for medium-energy heavy-ion facilities. In this talk, we will present the achievements and future of RIBF under the comparison with other powerful competitors.
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.
ODU, Norfolk, Virginia
Review of the theory, design and applications of Spoke cavities, with particular emphasis on SRF spoked cavities. Aspects of low level RF control for spoke cavities will also be presented.
ANL, Argonne
Recent developments for cryomodules required for various low- and medium beta- CW ion accelerator projects will be presented. Comparisons of the designs, fabrication technology and assembly procedures of cryomodules will be discussed. To date, development in this area has been mostly for basic science applications, however, there is also considerable interest in ion accelerators for other applications such as national defense, medicine and accelerator driven systems. The outlook for and some development requirements of SRF cryomodules for these applications will be discussed.
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
BNL 200 MeV linac has been under operation since 1970 and gone through several changes during its 40 year lifetime. The latest reconfiguration in low and medium energy (35 and 750 keV) beam transport lines results in about a factor of 2 reduction in the transverse emittance for the accelerated polarized proton beam, and for the unpolarized high current H- beam a several fold reduction in the radiation levels due to beam losses throughout the linac and isotope production facility complex with more beam current on the isotope production target. These improvements are achieved by proper matching into the linac in longitudinal as well as transverse phase space. This paper will emphasize how longitudinal matching resulted in lower emittance and beam losses.
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.
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
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.
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.
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.
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.
IHEP Beijing, Beijing
In the 324MHz CSNS Drift Tube Linac, the electromagnetic quadrupoles will be used for transverse focusing. The R&D of the quadrupole for the lower energy section of the DTL is a critical issue because the size of the drift tube at this section is so small that it is not possible to apply the conventional techniques for the fabrication. Then the electromagnetic quadrupoles containing the SAKAE coil and a drift tube prototype containing an EMQ have been developed. In this paper, the details of the design, the fabrication process, and the measurement results for the quadrupole magnet are presented.
ITEP, Moscow
Intense heavy ion beam is very efficient tool to generate high energy density states in macroscopic amounts of matter. As result it enables unique methods to study astrophysical processes in the laboratory under controlled and reproducible conditions. For advanced experiments on high energy density physics the cylindrical target irradiated by hollow cylindrical beam is required. This combination provides extremely high densities and pressures on the axis of imploding cylinder. A new method for RF rotation of the ion beam is applied for required hollow beam formation. The RF system consisting of two four-cell H-mode cavities is under development for this purpose now. The cavities frequency has been chosen 298 MHz, which is sufficient for uniform target illumination at 100 ns pulse duration. The deflecting electrodes shape has been optimized to provide the uniform deflection of all particles in beam's cross-section. The prototype of the deflector cell was constructed. A measured electro-dynamics characteristic is presented. As well frequency corrections methods are considered in this paper.
Soreq NRC, Yavne
The SARAF front end is composed of a proton/deuteron ECR ion source and a LEBT to match the beam to a 4-rod RFQ. The LEBT is consisting of an analyzing magnet, an aperture, three magnetic solenoid lenses and a diagnostic system. The typical operation vacuum, downstream the analyzing magnet, is of the order of 10-6 mbar at 5 mA analyzed beam current. In the emittance measurement we identify a beam of secondary-species particles, differently affected by the solenoid and so arriving with a different phase-space profile at the emittance detector. The secondary beam is the result of a charge exchange interaction in which an ion interacts with residual gasses in the beam line, most likely hydrogen gas coming from the ion source, and become neutral. For 20 keV protons colliding with H2 the calculated ion neutralization rate is 1%/m/10-6 mbar. Since the neutral portion of the beam is not affected by the magnetic focusing / steering elements, a none concentric neural and ion beams in the phase-space is a measure of mistuned beam or misalign magnets. These effects were proved and followed by beam dynamics simulation and are used to match the beam to the RFQ.
JAEA/J-PARC, Tokai-mura
JAEA, Ibaraki-ken
KEK/JAEA, Ibaraki-Ken
Residual gas in beam transport line essentially affects the beam loss and residual radiation on the accelerator. J-PARC linac is usually operated under 1.0 ·10-6 to 1.0 ·10-5 Pa in SDTL and A0BT sections. In this situation, no serious beam loss was observed during the beam operation. In future development of J-PARC linac, because the peak beam energy and output will be increased, it is getting more serious problem. Before the development, it is important to understand a cause of beam loss and relation between beam loss and residual gas pressure. We measured beam loss at the normal and worse vacuum condition in both SDTL and A0BT sections. The result indicates that the beam loss depends on the residual gas pressure and position where the beam loss occurs is about 20 to 30 meter downstream. This suggests the optimum position for installation of vacuum system to minimize the beam loss. In this paper, we describe the experimental result and its discussions. In addition, the cause of the beam loss is considered to be a stripping from negative hydrogen ions to neutral hydrogen atoms. This mechanism is also discussed in this paper.
RAS/INR, Moscow
The monitor to measure a transverse cross section of the accelerated beam has been developed and implemented in INR Linac. Operation of the monitor is based upon utilization of residual gas ionization. Ion flux cross section after extraction of the ions from the beam line by electrostatic field and subsequent energy separation in electrostatic analyzer reproduces a transverse cross section of the accelerator beam. Aμchannel plate intensifier followed by a phosphor screen is used to observe ion cross section. The image is optically transmitted to a CCD camera installed remotely and shielded for protection. The monitor enables to observe beam cross section, beam profiles and beam position, as well as their evolution in time within a wide range of beam intensities and energies. Monitor operation and parameters are described. Some experimental results are presented.
ANL, Argonne
An emittance meter based on a pepper-pot coupled to a CsI (Tl) scintillator has been developed over the last several years [1] at Argonne National Laboratory. A compact version of such a probe for on-line emittance measurements has been designed, built and installed into the low energy beam transport (LEBT) line of the Argonne Tandem Linac Accelerator System (ATLAS) and also downstream of the gas catcher of the recently commissioned Californium Rare Isotope Breeder Upgrade (CARIBU). The probe has demonstrated the capability to measure emittance of ion beams with a current density as low as 10 nA/cm2. Systematic emittance measurements in the ATLAS LEBT for different ion species have been done and results will be presented. The probe, based on a pepper-pot coupled to an MCP viewing system, has been designed and built to measure the emittance of low intensity (102-106 ions/s) radioactive CARIBU ion beams.
[1] S. Kondrashev et al. Development of a pepper-pot emittance probe and its application for ECR ion beam studies. Nuclear Instruments and Methods in Physics Research A 606, 2009, pp. 296-304.
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.
ORNL, Oak Ridge, Tennessee
The latest modifications of the MEBT emittance scanner and the test results are presented. The scanner consists of a slit and harp placed in the MEBT section of SNS Linac with H- energy of 2.5 MeV. It was initially commissioned during the early days of SNS. The initial design allowed to get information about beam core but was incapable of getting precise data about halo. Several improvements in hardware and software were performed recently. They significantly increased signal to noise ratio, reduced harp wires electron coupling and increased scan speed. The latest measurements with the new system show a good agreement with the simulation results from simple models.
FRIB, East Lansing, Michigan
NSCL, East Lansing, Michigan
The Facility for Rare Isotope Beams (FRIB) at Michigan State University will utilize a high power, heavy-ion linear accelerator to produce rare isotopes in support of a rich program of fundamental research. The linac will consist of a room temperature-based front-end system producing beams of approximately 0.3 MeV/u. Three additional superconducting linac segments will produce beams of >200 MeV/u with a beam power of up to 400 kW. Because of the heavy-ion beam intensities, the required diagnostics will be largely based on non-interceptive approaches. The diagnostics suites that will support commissioning and operation are divided into lower energy <0.3 MeV/u front-end and higher energy driver linac systems (<200 MeV/u for uranium). The instruments in the driver linac include strip-line BPM, toroid, BCM, and 3-D electron scanners to measure rms beam size. A desired availability of >90% and an aggressive commissioning schedule lead to some challenges in beam diagnostics requirements that will be addressed in this paper. We are committed to using an architecture common with the rest of FRIB for the data acquisition and timing which will also be discussed in this paper.
CERN, Geneva
Université Blaise Pascal, Clermont-Ferrand
As part of the CERN LHC injector chain upgrade, LINAC4 will accelerate H- ions from 45 keV to 160 MeV. A number of wire grids and wire scanners will be used to characterize the beam transverse profile. This paper covers all monitor design aspects intended to cope with the required specifications. In particular, the overall measurement robustness, accuracy and sensitivity must be satisfied for different commissioning and operational scenarios. The physics mechanisms generating the wire signals and the wire resistance to beam induced thermal loads have been considered in order to determine the most appropriate monitor design in terms of wire material and dimensions.
NSCL, East Lansing, Michigan
The US Department of Energy Facility for Rare Isotope Beams (FRIB) at Michigan State University includes a heavy ion superconducting linac capable of accelerating all ions up to uranium with energies higher than 200 MeV/u and beam power up to 400 kW. At an energy of approximately 17 MeV/u we plan to strip the beam to reduce the voltage needed in the rest of the linac to achieve the final energy. The design of the stripper is a challenging problem due to the high power deposited (approximately one kW) in the stripper media by the beam in the small beam size. One of the options being considered is a carbon foil stripper. We have developed a test chamber to study the thermal mechanical properties of different stripping media candidates (amorphous carbon, graphene, diamond). This chamber utilizes an electron beam to deposit powers similar to what the FRIB stripper will see in operation. The thermo-mechanical studies are a necessary condition but not sufficient. The effect of radiation damage must also be studied. We have utilized heavy ions (Pb) from the K500 cyclotron to study this issue. We present in this paper a summary of the requirements and the status of the studies.
NSCL, East Lansing, Michigan
BNL, Upton, Long Island, New York
ANL, Argonne
The US Department of Energy Facility for Rare Isotope Beams (FRIB) at Michigan State University includes a heavy ion superconducting linac capable of accelerating all ions up to uranium with energies higher than 200 MeV/u and beam power up to 400 kW. To achieve these goals with present ion source performance it is necessary to accelerate simultaneously two charge states of uranium from the ion source in the first section of the linac. At an energy of approximately 17 MeV/u we plan to strip the uranium beam to reduce the voltage needed in the rest of the linac to achieve the final energy. Up to five different charge states are planned to be accelerated simultaneously after the stripper. The design of the stripper is a challenging problem due to the high power deposited (approximately one kW) in the stripper media by the beam in a small spot. To assure success of the project we have established a research and development program that includes several options: carbon or diamond foils, liquid lithium films, gas strippers and plasma strippers. We present in this paper a summary of the requirements and a general description of the status of the different options.
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.
TERA, Novara
EPFL, Lausanne
A.D.A.M. S.A., Geneva
IFIC, Valencia
CERN, Geneva
Proton and carbon ion beams present advantageous depth-dose distributions with respect to X-rays. Carbon ions allow a better control of "radioresistant" tumours due to their higher biological response. For deep-seated tumours proton and carbon ion beams of some nA and energies of about 200 MeV and 400 MeV/u respectively are needed. For these applications TERA proposed the "cyclinac": a high-frequency linac which boosts the hadrons accelerated by a cyclotron. The dimensions of the complex can be reduced if higher accelerating gradients are achieved in the linac. To test the maximum achievable fields, a 3 GHz cavity has been built by TERA. The 19 mm-long cell is foreseen to be excited at 200 Hz by 3 us RF pulses and should reach a 40 MV/m accelerating gradient, which corresponds to a peak surface electric field Es of 260 MV/m. In a first high-power test performed at CTF3 the cell was operated at 50 Hz with a maximum peak power of 1 MW. The maximum Es achieved was above 350 MV/m. The breakdown rate at these field values was around 10-1 bpp/m. The maximum value of the modified Poynting vector is close to the best values achieved by high gradient structures at 12 and 30 GHz.
NSCL, East Lansing, Michigan
INFN/LNL, Legnaro (PD)
FZJ, Jülich
Niobium quarter-wave resonators (QWRs) and half-wave resonators (HWRs) are being developed at Michigan State University for two projects: a 3 MeV per nucleon superconducting linac for re-acceleration of exotic ions (ReA3, under construction, requiring 15 resonators), and a 200 MeV per nucleon driver linac for the Facility for Rare Isotope Beams (FRIB, under design, requiring 344 resonators). The QWRs (80.5 MHz, optimum beta = 0.041 and 0.085) are required for both ReA3 and FRIB. Both include stiffening elements and frictional dampers. Nine beta = 0.041 QWRs have been fabricated; seven of them have been Dewar tested successfully with a helium vessel for use in ReA3. Production and testing of ten beta = 0.085 QWRs is in progress. The HWRs (322 MHz, optimum beta = 0.29 and 0.53, required for FRIB) are designed for mechanical stiffness and low peak surface magnetic field. A prototype beta = 0.53 HWR has been fabricated, and a prototype beta = 0.29 HWR is planned. This paper will cover the RF and mechanical requirements, the resonator and vessel design, and Dewar testing of production resonators.
LANL, Los Alamos, New Mexico
The linear accelerator at the Los Alamos Neutron Science Center (LANSCE) accelerates both protons and H-minius ions using Cockroft-Walton-type injectors, a drift-tube linac and a side-coupled linac. The vacuum is maintained in the range of 10-6 to 10-7 Torr; the residual gas in the vacuum system results in some stripping of the electrons from the H-minus ions resulting in beam spill and the potential for unwanted proton beams delivered to experiments. We have measured the amount of fully-stripped H-minus beam (protons) that ends up at approximately 800MeV in the beam switchyard at LANSCE using image plates as very sensitive detectors. I will present the motivation for the measurement, the measurement technique and results, and calculations to model the results and possible mitigation schemes.
INFN/LNL, Legnaro (PD)
As far as beam dynamics is concerned, the layout of the PIAVE-ALPI SuperConducting linac, it is injected either by a XTU tandem, up to 14 MV, or by the s-c PIAVE injector, made with 2 SC-RFQ. The linac (at the present 64 cavities for a total voltage up to 48 MV) is build up in two branches connected by an achromatic and isochronous U-bend. The PIAVE-ALPI complex is able to accelerate beams up to A/q = 7. The linac is quite complex due the presence of several accelerating, (SC RFQs and cavities), focusing and transport elements. The linac operation, optimized for the needs of the users, is described. In particular the effects of a flexible use of the cavities on the beam dynamics is addressed. The automatic tuning procedure of the Toutatis-Tracewin programs is used for the simulation, and the comparison with the actual linac performances is reported.
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.
LANL, Los Alamos, New Mexico
JYFL, Jyvaskyla
The Los Alamos Neutron Sciene Center (LANSCE) accelerator facility has the capability of accelerating both H+ and H- ion beams. LANSCE H- User Programs rely on the ion source's ability to deliver an appropriate beam current within a given emittance limit. An active H- ion source development program is ongoing with the goal of improving source performance (e.g. reliability, availability, increased out current, etc.) The formation of H- ions in the LANSCE negative ion source occurs on the surface of a negatively biased electrode (converter), exposed to a flux of positive ions incident from a cusp-confined, filament-driven discharge. The source typically delivers a 16 mA pulsed (60 Hz) H- beam with a source lifetime of 35 days. A program to reach 28-35 mA with the LANSCE source is outlined. It includes efforts to improve filament performance, elevating source body temperatures, optimizing converter geometry and location, optimizing converter cooling, and increasing the number of filaments from two to three.
IHEP Beijing, Beijing
STFC/RAL, Chilton, Didcot, Oxon
The type of the H- ion source foe CSNS is a Penning Surface Plasma Source (SPS). The output energy of the source is 50keV and the pulsed current of H- beam is 20mA with a rms. emittance of 0.2π mm.mrad. The construction of H- ion source test stand for CSNS is finished and commissioning of the source is being done. Up to now, stable H- ion beam with a current up to 45mA and energy of 50keV is achieved. Emittance measurements of the beam is also being prepared.
INFN/LNS, Catania
GSI, Darmstadt
According to the model that has driven the development of ECRIS in the last years, a large variation of the pumping microwave frequency (order of GHz) boosts the extracted current for each charge state because of a larger plasma density. Recent experiments have demonstrated that even slight frequency's changes (of the order of MHz) considerably influence the output current, and also the beam properties after the extraction (beam shape, brightness and emittance). In order to investigate how this fine tuning affects the plasma heating, a set-up for the injection of different microwave frequencies into the ECRIS cavity has been prepared. The microwave power is fed by means of a Travelling Wave Tube amplifier with a broad operating frequency range. The frequency can be systematically changed and the beam output is recorded either in terms of charge state distributions and beam emittance. The detected brehmsstralung X-rays are additionally analysed: they give insights about the electron energy distribution function (EEDF). The results are compared with simulations and data coming from previous preliminary experiments.
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 %.
ORNL, Oak Ridge, Tennessee
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is in the process of ramping up the H- ion beam power to 1.4 MW, its full design power for the neutron production. For robust operation of the neutron facility, work is underway for various improvements on the RF power systems of the ion source. For short and long-term higher beam power operations, an RF-driven H- ion source employing external antenna with a water-cooled, ceramic aluminum nitride (AlN) plasma chamber has been developed*. The new ion source has been tested to deliver up to 42 mA in the SNS Front End (FE) and unanalyzed beam currents up to ~100mA (60Hz, 1ms) in the ion source test stand. In addition to the external antenna design for improved antenna lifetime, other RF developments for improvement of reliability are running 2 MHz power amplifier system is with isolation transformer, employing full solid-state 2 MHz power amplifier, more precise 2 MHz capacitive impedance matching, and upgrading 13 MHz RF plasma gun system. This paper discusses the engineering solutions with analysis and development of the above RF systems for the new ion source system.
R.F. Welton, N.J. Desai, J. Carmichael, B. Han, Y.W. Kang, S.N. Murray, T. Pennisi, M. Santana, and M.P. Stockli, "The Continued Development of the SNS External Antenna H- Ion Source," ICIS2009
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.