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| MPPE082 | Non-Linear Beam Dynamics in High Resolution Multi-Pass Time of Flight Mass Separator | ion, simulation, extraction, resonance | 4105 | ||
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Funding: This work was supported by the UNIRIB collaboration and Oak Ridge Associated Universities. |
A multi-pass time-of-flight (MTOF) mass separator is under development by the UNIRIB collaboration. The MTOF consists of two coaxial electrostatic mirrors, focusing lenses and auxiliary injection, extraction and separation elements. The injected ions having almost the same energy but different masses undergo hundreds or thousands of reflections between the mirrors. In the course of this periodic motion, the ions of different masses and hence velocities are spatially separated in longitudinal direction. The periodic motion in the MTOF has been investigated with a recently developed ray tracing program utilizing the canonical integration technique. Results of the performed numerical simulations are discussed. The simulations displayed nonlinear character of the ion’s behavior both in transverse and longitudinal phase spaces. The ion’s transverse stability and longitudinal isochronicity were the matters of primary attention. It is shown in particular that at transverse tunes of around q=0.75 the system can be adjusted to be isochronous up to at least the 3rd order of the ToF optical aberrations. |
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| MOPB002 | High Intensity High Charge State ECR Ion Sources | ion, plasma, electron, emittance | 179 | ||
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Funding: This work was supported by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Nuclear Physics Division of the U.S. Department of Energy under Contract DE AC03-76SF00098. |
The next-generation heavy ion beam accelerators such as the proposed Rare Isotope Accelerator (RIA), the Radioactive Ion Beam Factory at RIKEN, the GSI upgrade project, the LHC-upgrade, and IMP in Lanzhou require a great variety of high charge state ion beams with a magnitude higher beam intensity than currently achievable. High performance Electron Cyclotron Resonance (ECR) ion sources can provide the flexibility since they can routinely produce beams from hydrogen to uranium. Over the last three decades, ECR ion sources have continued improving the available ion beam intensities by increasing the magnetic fields and ECR heating frequencies to enhance the confinement and the plasma density. With advances in superconducting magnet technology, a new generation of high field superconducting sources is now emerging, designed to meet the requirements of these next generation accelerator projects. The talk will briefly review the field of high performance ECR ion sources and the latest developments for high intensity ion beam production. The currently most advanced next-generation superconducting source ECR ion source VENUS will be described in more detail. |
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| MOPB003 | Progress with the 2Q-LEBT Facility for the RIA Project | ion, emittance, rfq, simulation | 253 | ||
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Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. W-31-109-ENG-38. |
The Rare Isotope Accelerator (RIA) facility utilizes the concept of simultaneous acceleration of two charge states from the ion source. We are building a prototype two charge-state (2Q) injector of the RIA Driver Linac, which includes an ECR ion source originally built by Berkeley Ion Equipment Corporation, a LEBT and one-segment of the prototype RFQ. The reassembly and commissioning of the ECR source has been completed. During the commissioning process we modified and replaced several major components of the BIE-100 to increase the source performance. A new diagnostic station has been designed and built for accurate measurements of the output beam emittance. The paper will discuss detailed beam dynamics studies together with extensive emittance measurements of various ion beams. The status of the design and fabrication of 100 kV high voltage platform, achromatic bending system, multi-harmonic buncher, and a full power 57.5 MHz RFQ segment will be presented. |
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| MOPB005 | Advances in the Performance of the SNS Ion Source | ion, SNS, plasma, linac | 472 | ||
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Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. |
The ion source developed for the Spallation Neutron Source* (SNS) is a radio frequency, multi-cusp source designed to produce ~ 40 mA of H- with a normalized rms emittance of less than 0.2 pi mm mrad. To date the source has been utilized in the commissioning of the SNS accelerator, delivering beams of 10-50 mA with duty-factors of typically ~0.1% for operational periods of several weeks and availabilities now ~99%. Ultimately the SNS facility will require beam duty-factors of 6% (1 ms pulse length, 60 Hz repetition rate, 21 day run-period). Over the last year, several experiments were performed in which the ion source was continuously operated at full duty-factor and maximum beam current on a dedicated test stand. Recently, a breakthrough in our understanding of the Cs release process has led to the development of a new source conditioning technique which resulted in a dramatic increase in beam persistence with time. Average H- beam attenuation rates have been improved from ~5 mA/day to ~0.4 mA/day, allowing beams in excess of 30 mA to be delivered continuously at full duty factor for periods of ~20 days. Prior to this development, full duty factor beams could only be sustained for periods of several hours. |
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| TPAT029 | RIA Beam Dynamics: Comparing TRACK to IMPACT | linac, simulation, lattice, injection | 2095 | ||
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Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. W-31-109-ENG-38. |
In order to benchmark the newly developed beam dynamics code TRACK we have performed comparisons with well established existing codes. During code development, codes like TRANSPORT, COSY, GIOS and RAYTRACE were used to check TRACK's implementation of the different beam line elements. To benchmark the end-to-end simulation of the RIA driver linac, the simulation of the low-energy part (from the ion source to the entrance of the SC linac) was compared with PARMTEQ and found to agree well. For the simulation of the SC linac the code IMPACT is used. Prior to these simulations, the code IMPACT had to be updated to meet the special requirements of the RIA driver linac. Features such as multiple charge state acceleration, stripper simulation and beam collimation were added to the code. IMPACT was also modified to support new types of rf cavities and to include fringe fields for all the elements. This paper will present a comparison of the beam dynamics simulation in the RIA driver linac between the codes TRACK and IMPACT. A very good agreement was obtained which represents another validation of both codes. |
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| TPPE004 | The Production of Negative Lithium Beams by Charge Exchange in Cesium Vapours | ion, target, electron, vacuum | 898 | ||
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These measurements were carried out at the Holifield Radioactive Ion Beam Facility of the Oak Ridge National Laboratory (ORNL-HRIBF) by researchers from the Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS), Catania, Italy and local staff. The Charge Exchange Cell (CEC) consisted of a vacuum chamber containing cesium vapours at a variable temperature, T, in which positive ions accelerated from an ion source were transformed into negative ones by collisions with the Cs atoms. The main goal of this test was to measure the production efficiency for 7Li- ions at different operating conditions, such as 7Li+ beam energy (5 to 55 keV) and Cs temperature (190 to 300 °C). Moreover, the efficiency measurements performed with a 6Li+ projectile beam gave clear indications about the isotopic shift effect. These results are useful to estimate the charge exchange efficiency for 8, 9Li, which will be the first radioactive beams to be produced at the EXCYT facility (EXotics with CYclotron and Tandem). The data showed that the charge exchange efficiency at the minimum energy suitable for beam handling (20-25 keV) is around 1%.
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| TPPE005 | 50keV, 50mA Pulsed Proton Injector for PEFP | proton, ion, extraction, rfq | 964 | ||
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Funding: This work is supported by the 21C Frontier R&D program in the Ministry of Science and Technology of the Korean government. |
Duoplasmatron type ion source with 50keV proton beam has been constructed and stably operated as the injector for Proton Engineering Frontier Project(PEFP). In DC operation, the beam current of 50mA with 50kV extraction voltage is routinely obtained. However, the pulsed operation mode of the ion source also has been considered to reduce beam induced damage at the entrance of RFQ. A high voltage pulse switch is connected between accelerating electrode and ground electrode for this purpose. The detailed scheme on the focusing of the pulsed proton beam with space charge compensation is in progress. Beam profile and current in front of RFQ will be measured by DCCT and optical measuring tools. |
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| TPPE006 | Radioactive Beams from 252CF Fission Using a Gas Catcher and an ECR Charge Breeder at ATLAS | ion, shielding, linac, beam-transport | 1000 | ||
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Funding: Department of Energy Office of Nuclear Science. |
An upgrade to the radioactive beam capability of the ATLAS facility has been proposed using 252Cf fission fragments thermalized and collected into a low-energy particle beam using a helium gas catcher. In order to reaccelerate these beams an existing ATLAS ECR ion source will be reconfigured as a charge breeder source. A 1Ci 252Cf source is expected to provide sufficient yield to deliver beams of up to ~106 far from stability ions per second on target. A facility description, the expected performance and the expected performance will be presented in this paper. This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract W-31-109-ENG-38. |
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| TPPE010 | A Parallel 3D Model for the Multi-Species Low Energy Beam Transport System of the RIA Prototype ECR Ion Source VENUS | simulation, ion, beam-transport, extraction | 1183 | ||
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Funding: This work was supported by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Nuclear Physics Division of the U.S. DOE under Contract DE AC03-76SF00098. |
The driver linac of the proposed Rare Isotope Accelerator (RIA) requires a great variety of high intensity, high charge state ion beams. In order to design and optimize the low energy beam line optics of the RIA front end, we have developed a new parallel three-dimensional model to simulate the low energy, multi-species beam transport from the ECR ion source extraction region to the focal plane of the analyzing magnet. A multi-section overlapped computational domain has been used to break the original transport system into a number of independent subsystems. Within each subsystem, macro-particle tracking is used to obtain the charge density distribution in this subdomain. The three-dimensional Poisson equation is solved within the subdomain and particle tracking is repeated until the solution converges. Two new Poisson solvers based on a combination of the spectral method and the multigrid method have been developed to solve the Poisson equation in cylindrical coordinates for the beam extraction region and in the Frenet-Serret coordinates for the bending magnet region. Some test examples and initial applications will also be presented. |
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| TPPE012 | Using the Orbit Tracking Code Z3CYCLONE to Predict the Beam Produced by a Cold Cathode PIG Ion Source for Cyclotrons under DC Extraction | emittance, plasma, ion, cyclotron | 1297 | ||
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Experimental measurements of the emittance and luminosity of beams produced by a cold-cathode Phillips Ionization Guage (PIG) ion source for cyclotrons under dc extraction are reviewed. (The source being studied is of the same style as ones that will be used in a series of 250 MeV proton cyclotrons being constructed for cancer therapy by ACCEL Inst, Gmbh, of Bergisch Gladbach, Germany.) The concepts of 'plasma boundary' and 'plasma temperature' are presented as a useful set of parameters for describing the initial conditions used in computational orbit tracking. Experimental results for r-pr and z-pz emittance are compared to predictions from the MSU orbit tracking code Z3CYCLONE with results indicating that the code is able to predict the beam produced by these ion sources with adequate accuracy such that construction of actual cyclotrons can proceed with reasonably prudent confidence that the cyclotron will perform as predicted.
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| TPPE015 | The Effusive-Flow Properties of Target/Vapor-Transport Systems for Radioactive Ion Beam Applications | target, ion, cathode, electron | 1422 | ||
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Funding: Research at ORNL is supported by the U.S. DOE under contract DE-AC05-00OR22725 with UT-Battelle, LLC. |
Radioactive atoms produced by the ISOL technique must diffuse from a target, effusively flow to an ion source, be ionized, be extracted, and be accelerated to research energies in a time commensurate with the lifetime of the species of interest. We have developed a fast valve system (closing time ~100 us) that can be used to accurately measure the effusion times of chemically active or inactive species through arbitrary geometry and size vapor transport systems with and without target material in the reservoir. The effusive flow times are characteristic of the system and thus serve as figures of merit for assessing the quality of a given vapor transport system as well as for assessing the permeability properties of a given target design. This article presents effusive flow data for noble gases flowing through a target reservoir and ion source system routinely used to generate radioactive species at the HRIBF with and without disks of 6 times and 10 times compressed Reticulated Vitreous Carbon Foam (RVCF) with the objective of determining the added delay time associated with each of these target matrices. |
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| TPPE017 | A New Broadband Microwave Frequency Device for Powering ECR Ion Sources | ion, radiation, injection, electron | 1529 | ||
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Funding: Research at ORNL is supported by the U.S. DOE under contract DE-AC05-00OR22725 with UT-Battelle, LLC. |
The multiple discrete frequency technique has been used to improve the performance of conventional B-field configuration ECR ion sources. However, the practical application of this technique is very costly, requiring multiple independent single-frequency rf power supplies and complicated rf injection systems. Broadband sources of rf power offer a low-cost and more effective method for increasing the physical size of the ECR zone within these ion sources. An Additive White Gaussian Noise Generator (AWGNG) system for injecting broadband rf power into these ion sources has been developed in conjunction with a commercial firm. The noise generator, in combination with an external oscillator and a traveling wave tube amplifier, can be used to generate broadband rf power without modifying the injection system. The AWGNG and its use for enhancing the performance of conventional B-field configuration ECR ion sources will be described. |
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| TPPE018 | Characterization of a Tubular Hot-Cavity Surface Ionization Source | ion, target, plasma, emittance | 1581 | ||
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Funding: Managed by UT-Battelle, LLC, for the U.S. DOE under contract DE-AC05-00OR22725. |
Elements with low ionization potentials can be efficiently ionized by positive surface ionization. It has been experimentally observed and theoretically shown that the ionization efficiency in a hot-cavity can be significantly higher than expected for the surface ionization mechanism. This is explained by the existence of a thermal plasma inside the cavity consisting of surface ionized ions and thermionic electrons. We have investigated the suggested ioniation mechanisms in a tubular hot-cavity surface ionization source where the area of the exit aperture is small compared with the tube inner surface. Thermal analyses of the tubular cavity and calculated mean number of wall collisions of a neutral particle in the cavity before escaping through the exit aperture are presented. Measured emittance and ionization efficiencies of various elements as a function of the cavity temperature for different cavity materials are discussed. |
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| TPPE019 | Laser Ion Source Development for ISOL Systems at RIA | laser, ion, target, radiation | 1640 | ||
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Funding: Managed by UT-Battelle, LLC, for the U.S. DOE under contract DE-AC05-00OR22725. |
The isobaric purity of radioactive ion beams (RIBs) is of crucial importance to many experiments. Laser ion sources based on resonant photoionization have already proved to be of great value at existing ISOL RIB facilities. In these ion sources, ions of a selected isotope are produced by laser radiation via stepwise atomic resonant excitations followed by ionization in the last transition. Because each element has its own unique atomic energy levels, the resonant photoionization process can provide elemental selectivity of nearly 100%. We have initiated a research effort to develop a prototype laser ion source with the potential to achieve the high selectivity and high efficiency required for research with ISOL-generated RIBs at the Rare Isotope Accelerator (RIA). A pilot experiment has been conducted to demonstrate resonant photoionization of three atomic species using all-solid-state tunable Ti:Sapphire lasers. Three Ti:Sapphire lasers were provided by the University of Mainz and used in the experiment for three-photon resonant ionization of the elements. Laser generated Sn, Ni, and Ge ions have been successfully obtained in a hot-cavity laser ion source with overall efficiencies of 22%, 2.7%, and 3.3%, respectively. |
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| TPPE021 | Simulation Studies of Diffusion-Release and Effusive-Flow of Short-Lived Radioactive Isotopes | target, ion, simulation, vacuum | 1739 | ||
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Funding: Research supported by the U.S. DOE under contract DE-AC05-00OR22725 with UT-Battelle, LLC. |
Delay times associated with diffusion release from targets and effusive-flow transport of radioactive isotopes to ion sources are principal intensity limiters at ISOL-based radioactive ion beam facilities, and simulation studies with computer models are cost effective methods for designing targets and vapor transport systems with minimum delay times to avoid excessive decay losses of short lived ion species. A finite difference code, Diffuse II, was recently developed at the Oak Ridge National Laboratory to study diffusion-release of short-lived species from three principal target geometries. Simulation results are in close agreement with analytical solutions to Fick’s second equation. Complementary to the development of Diffuse II, the Monte-Carlo code, Effusion, was developed to address issues related to the design of fast vapor transport systems. Results, derived by using Effusion, are also found to closely agree with experimental measurements. In this presentation, the codes will be used in concert to make realistic estimations of intensities of a number of short-lived isotopes that are candidates for use in future nuclear physics and nuclear astrophysics experiments at the HRIBF. |
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| TPPE022 | First Results on the Path Towards a Microwave-Assisted H- Ion Source | ion, plasma, electron, SNS | 1784 | ||
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Funding: This work supported by Office of Basic Energy Sciences, U.S. Department of Energy under Contract No. DE-AC03-76SF00098. |
A novel concept for creating intense beams of negative hydrogen ion beams is presented. In this approach, an ECR ion source operating at 2.45 GHz frequency is utilized as a primary plasma generator and coupled to an SNS-type multi-cusp H- ion source. The secondary source is driven by chopped dc power avoiding the use of filaments or of an internal rf antenna. The development of the new ion source is aimed at the future beam-power goal of 3 MW for the Spallation Neutron Source (SNS) that will be pursued after the start of SNS operations, but application to other proton driver accelerators that include an accumulator ring is feasible as well. The first two phases of this development effort have been successfully completed: assembly of a test stand and verification of the performance of an rf-driven SNS ion-source prototype; and extraction of electrons with more than 350 mA current from a 2.45-GHz ECR ion source obtained on loan from Argonne National Laboratory. The next goal is the demonstration of actual H- ion production by this novel, hybrid ion source. This paper describes the source principle and design in detail and reports on the current status of the development work. |
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| TPPE023 | Development and Performance of a Proton and Deuteron ECR Ion Source | proton, ion, emittance, simulation | |||
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A 5mA proton and deuteron rf source is under development at ACCEL. This source will provide the front end of our superconducting proton/deuteron linear accelerator. The design of the source is based on the proven AECL design of a 100 mA proton source. The paper will describe the design of the source and the layout of the test bench currently set up at ACCEL to characterize the source. Results of the beam dynamic simulations performed to optimize the source geometry based on KOBRA 3D will be presented and compared with first measurement results.
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| TPPE025 | Separating the Penning and Analysing Fields in the ISIS H- Ion Source | emittance, ion, vacuum, extraction | 1910 | ||
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Funding: This work was supported by the European Union High Performance Negative Ion Source (HP-NIS) network, contract number HPRI-CT-2001-50021. |
The development of H- ion sources with performances exceeding those achieved today is a key requirement for the next generation of high power proton accelerators. The Penning surface plasma source development program at ISIS is now well established. To allow different ion source designs to be fully tested, the ability to vary the Penning field is required. Until now the Penning field has been generated by the same magnetic circuit that creates the analyzing field, giving no practical way of altering the Penning field alone. This paper describes the infrastructure changes required to allow the Penning field to be independently varied. The effect the Penning field has on beam current, emittance and discharge stability are discussed. |
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| TPPE028 | In-Situ Electron Cyclotron Resonance (ECR) Plasma Potential Determination Using an Emissive Probe | plasma, electron, ion, monitoring | 2035 | ||
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Funding: This research was sponsored by the U.S. DOE under contract No. DE-AC05-00OR22725 with UT-Battelle, LLC. HJY acknowledges support from the Korean Science Education Foundation (KOSEF). |
In this paper, real-time, in-situ, plasma potential measurements are reported for an ECR ion source and correlated with extracted beam characteristics. The local real-time plasma potential of the ORNL CAPRICE ECR ion source was measured using an emissive probe, which was inserted perpendicularly from the plasma chamber wall at the mid-plane of the ECR zone between one of the six radial loss cones of the magnetic field structure, where perturbation of the main ECR plasma is expected to be small. Slots machined through the plasma- and puller-electrodes at the plasma chamber wall radius permitted insertion of the probe from the extraction side of the ECR source without perturbation of the coaxial microwave injection. The emissive probe technique permits plasma potential determination independent of plasma conditions and avoids problems related to probe geometry. The probe loop tip was pointed toward the chamber center in a radial plane and was located about 5 mm outside of the ECR zone. Details of the measurements, and a comparison with an external-beam-deceleration-based plasma potential determination will be presented. |
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| TPPE032 | Particle-in-Cell Simulations of the VENUS Ion Beam Transport System | simulation, ion, extraction, beam-transport | 2236 | ||
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Funding: This work was supported by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Nuclear Physics Division of the U.S. DOE under Contract DE AC03-76SF00098 |
The next-generation superconducting ECR ion source VENUS serves as the prototype injector ion source for the linac driver of the proposed Rare Isotope Accelerator (RIA). The high-intensity heavy ion beams required by the RIA driver linac present significant challenges for the design and simulation of an ECR extraction and low energy ion beam transport system. Extraction and beam formation take place in a strong (up to 3T) axial magnetic field, which leads to significantly different focusing properties for the different ion masses and charge states of the extracted beam. Typically, beam simulations must take into account the contributions of up to 30 different charge states and ion masses. Two three-dimensional, particle-in-cell codes developed for other purposes, IMPACT and WARP, have been adapted in order to model intense, multi-species DC beams. A discussion of the differences of these codes and the advantages of each in the simulation of the low energy beam transport system of an ECR ion source is given. Direct comparisons of results from these two codes as well as with experimental results from VENUS are presented. |
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| TPPE037 | Relative Contribution of Volume and Surface-Plasma Generation of Negative Ions in Gas Discharges | ion, plasma, electron, cathode | 2482 | ||
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The relative contribution of volume and surface-plasma generation of extracted ?- ions in gas discharge sources will be analyzed. At the present time, it is well known that surface-plasma generation of extracted ?- ion is dominate above volume processes in discharges with admixture of cesium or other catalysts with low ionization potential. We will attract attention to evidences, that surface-plasma generation can be enhanced in high density discharges without cesium after electrode activation by high temperature conditioning in discharge. A diffusion of impurity with a low ionization potential can be a reason of observed enhancement of H- emission. For the effective generation of ?- ion beams in discharge without cesium, it is necessary to optimize surface-plasma generation of extracted ?- ion. Such optimization allows considerable improvement of ?-/D- sources characteristics.
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| TOPD004 | RIB Facility at VECC Kolkata–A Status Report | target, rfq, linac, ion | 395 | ||
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The status of the Radioactive Ion Beam (RIB) facility being built at VECC, Kolkata will be presented. The facility is being built around the existing K=130 cyclotron and will be installed in one of the existing experimental caves. The scheme is to use proton and alpha particles from the cyclotron on a thick production target placed inside an integrated surface ion-source. Radioactive ions with charge state q=1+ extracted from the target-ion-source are to be injected into an on-line ECRIS "charge breeder" for further ionization to q=n+. The 1keV/u, q/A=1/16, RIB of interest will be selected in an isotope separator downstream of the ECRIS and accelerated initially to about 86 keV/u in a Radio Frequency Quadrupole (RFQ) linac and subsequently to about 400 keV/u in three IH-Linac tanks. Since RIB development is R&D intensive, it has been decided to build at first all the basic building blocks and to carry out simultaneously thick target R&D and release measurements using the existing He-jet ISOL facility. Future expansion for further upgradation of energy has been planned. The design of the facility and some recent results will be presented.
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| WPAE010 | Neutron Flux and Activation Calculations for a High Current Deuteron Accelerator | ion, vacuum, target, simulation | 1192 | ||
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Neutron analysis of the first Neutral Beam (NB) for the International Thermonuclear Experimental Reactor (ITER) was performed to provide the basis for the study of the following main aspects: personnel safety during normal operation and maintenance, radiation shielding design, transportability of the NB components in the European countries. The first ITER NB is a medium energy light particle accelerator. In the scenario considered for the calculation the accelerated particles are negative deuterium ions with maximum energy of 1 MeV. The average beam current is 13.3 A. To assess neutron transport in the ITER NB structure a mathematical model of the components geometry was implemented into MCNP computer code (MCNP version 4c2. "Monte Carlo N-Particle Transport Code System." RSICC Computer Code Collection. June 2001). The neutron source definition was outlined considering both D-D and D-T neutron production. FISPACT code (R.A. Forrest, FISPACT-2003. EURATOM/UKAEA Fusion, December 2002) was used to assess neutron activation in the material of the system components. Radioactive inventory and contact dose rate were assessed considering the potential operative scenarios.
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| WPAT012 | Status and Test Results of HPRF System for PEFP | rfq, klystron, proton, pick-up | 1288 | ||
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Funding: This work is supported by the 21C Frontier R&D program in the Ministry of Science and Technology of the Korean government. |
The PEFP 20MeV proton accelerator is composed of 3MeV RFQ and 20MeV DTL and two sets of 1MW, 350MHz RF system are required for each accelerating structure. The high power RF system for 3MeV RFQ was already installed and operated to drive the RFQ. The klystron was tested up to 600kW itself and operated in pulse routinely. The HPRF system for 20MeV DTL which consists of 4 tanks was installed, and the RF test for 4 tanks has been carried out. The ridge-loaded power coupler was designed and installed to drive RFQ and DTL. In this paper, the status and test results of the RF system for 20MeV proton accelerator are discussed. |
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| RPAP024 | The ORNL Multicharged Ion Research Facility (MIRF) High Voltage Platform Project | ion, permanent-magnet, electron, beam-transport | 1853 | ||
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Funding: This research was sponsored by the Office of Basic Energy Sciences, and the Office of Fusion Energy Sciences of the U.S. DOE under contract No. DE-AC05-00OR22725 with UT-Battelle, LLC. |
We report on initial testing and implementation of a new high voltage platform recently installed at the ORNL MIRF. The platform is powered by a 250 kV, 30 kVA isolation transformer and features an all permanent magnet Electron Cyclotron Resonance (ECR) ion source, designed and fabricated at CEA/Grenoble, that utilizes microwave power levels of up to 750W in the frequency range 12.75 – 14.5 GHz to provide intense dc beams of singly and multiply charged ions for acceleration to energies up to 270 x q keV. The primary application of these ion beams is to study fundamental collisional interactions* of multicharged ions with electrons, atoms, and surfaces. More applied investigations in the area of ion implantation,** and ion beam development for use in semiconductor doping operations are carried out as well. Design details of the HV platform and the associated beamline-switchyard will be presented at the conference, together with performance characteristics of the all permanent magnet ECR source, of the beam transport from ion source to end-station, and of a novel electrostatic spherical sector beam switcher for directing beam to the various on-line experiments. *F.W . Meyer, Trapping Highly Charged Ions: Fundamentals and Applications, J. Gillaspy, ed., Nova Science Pub., New York, 2000, pp. 117-164. **F. W. Meyer et al., AIP Conf. Proc. 635, p. 125 (2002). |
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| RPAP040 | Design of a Fast Neutral He Beam System for Feasibility Study of Charge-Exchange Alpha-Particle Diagnostics in a Thermonuclear Fusion Reactor | ion, diagnostics, extraction, plasma | 2630 | ||
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For alpha-particle diagnostics in a thermonuclear fusion reactor, neutralization using a fast (~2 MeV) neutral He beam produced by the spontaneous electron detachment of a He- is considered most promising. However, the beam transport of produced fast neutral He has not been studied, because of difficulty for producing high-brightness He- beam. Double-charge-exchange He- sources and simple beam transport systems were developed and their results were reported in the PAC99* and other papers.** To accelerate an intense He- beam and verify the production of the fast neutral He beam, a new test stand has been designed. It consists of a multi-cusp He+ source, alkali metal gas cell for double charge exchange, a stigmatic 90 degree bending magnet as an ion separator, an accelerating tube and a free-flight tube to produce fast neutral He beam by autodetachment. The beam parameters of the He- beam are planed to be 150 keV of the beam energy and 10 uA of the beam current. A He+ beam of about 10 mA is extracted from the ion source and accelerated up to 15~25 keV for the effective charge exchange. Details of the design of the test stand and the brief result of the beam optics will be presented.
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*M. Sasao et al., Proc. of PAC99, pp. 1306-1308. **M. Sasao et al., Rev. Sci. Instr. Vol.69, pp.1063-1065 (1998). |
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| RPAP045 | Development of Laser-Induced Fluorescence Diagnostic for the Paul Trap Simulator Experiment | ion, laser, diagnostics, background | 2878 | ||
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Funding: Research Supported by the U.S. Department of Energy. |
The Paul Trap Simulator Experiment (PTSX) is a cylindrical Paul trap whose purpose is to simulate the nonlinear dynamics of intense charged particle beam propagation in alternating-gradient magnetic transport systems. For the in-situ measurement of the transverse ion density profile in the PTSX device, which is essential for the study of beam mismatch and halo particle production, a laser-induced fluorescence diagnostic system is being developed. Instead of cesium, which has been used in the initial phase of the PTSX experiment, barium has been selected as the preferred ion for the laser-induced fluorescence diagnostic. The installation of the barium ion source and the characterization of the tunable dye laser system are discussed. The design of the collection optics with an intensified CCD camera system is also discussed. Finally, initial test results using the laser-induced fluorescence diagnostic will be presented. |
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| RPPT064 | Holifield Radioactive Ion Beam Facility Development and Status | target, ion, extraction, light-ion | 3641 | ||
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Funding: Managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. |
The Holifield Radioactive Ion Beam Facility (HRIBF) is a national user facility dedicated to nuclear structure, reactions, and nuclear astrophysics research with radioactive ion beams (RIBs) using the isotope separator on-line (ISOL) technique. An integrated strategic plan for physics, experimental systems, and RIB production facilities have been developed and implementation of the plan is under way. Specific research objectives are defined for studying the nature of nucleonic matter, the origin of elements, solar physics, and synthesis of heavy elements. Experimental systems upgrade plans include new detector arrays and beam lines, and expansion and upgrade of existing devices. A multifaceted facility expansion plan includes a $4.75M High Power Target Laboratory (HPTL), presently under construction, to provide a facility for testing new target materials, target geometries, ion sources, and beam preparation techniques. Additional planned upgrades include a second RIB production system (IRIS2), an external axial injection system for the present driver cyclotron, ORIC, and an additional driver accelerator for producing high-intensity neutron-rich beams. |
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| FPAE033 | Operational Availability of the SNS During Commissioning | linac, SNS, ion, diagnostics | 2289 | ||
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Funding: This work was supported by SNS through UT-Batelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. The SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge. |
The SNS Front End, Drift Tube Linac and most of the Coupled Cavity Linac have been operated during commissioning. Operating statistics were taken and used by system owners to target developments to improve accelerator availability. This progression will be shown along with the overall availability goals of the SNS and a RAM calculation showing the system and subsystem availability required to meet these goals. |
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| FPAE040 | First Operation of PIAVE, the Heavy Ion Injector Based on Superconducting RFQ's | vacuum, ion, linac, acceleration | 2621 | ||
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The Positive Ion Accelerator for low-Velocity Ions (PIAVE), based on superconducting RFQ's (SRFQ's), has been completed in fall 2004 with the first acceleration of beams from the ECR ion source. Superconducting RFQ's were used, for the first time, for beam acceleration on a user-oriented accelerator complex. A general status of the injector performances is given: it includes, besides the SRFQ's, eight superconducting (SC) QWR's and three bunchers; the beam is received from an ECR source on a HV platform and is delivered, through the SC accelerator ALPI, to nuclear physics experimental apparatuses. The paper emphasizes, in particular, the technological challenges related to the operation of the SC cavities, the cryogenics, control, diagnostics and vacuum systems.
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| FPAE051 | Performance of a CW RFQ Injector for the IUCF Cyclotron | cyclotron, proton, rfq, ion | 3179 | ||
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Funding: The State of Indiana, Indiana University, and the DOE (Grant No DE-FG-02000ER62966) supported this work. |
A 750 keV RFQ proton pre-injector was installed in place of a 600 keV Cockroft-Walton high voltage terminal for the IUCF k220 Cyclotron.* The pre-injector consists of a 20 keV microwave ion source and LEBT, a unique design 750 keV CW RFQ, and a short transfer beam line to the k15 injector cyclotron center region.** This pre-injector system was installed and commissioned in June of 2003 and is now in routine service as the sole injection system to the cyclotrons. This contribution will discuss the performance of the CW RFQ pre-injector and the transmission properties of the beam through the cyclotrons. *D.L.Friesel, et al., App. of Acc. in Res. and Ind., eds. J.L. Duggan and I.L. Morgan, Denton, 651(2000). **V.P. Derenchuk, et al., 2003 Particle Accelerator Conference, Portland, OR, (2003), edited by A. Jackson and E. Lee. |
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| FPAE057 | Beam Dynamics Studies and Beam Quality in the SNS Normal-Conducting Linac | emittance, linac, ion, simulation | 3381 | ||
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Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos and Oak Ridge. |
The Spallation Neutron Source accelerator systems will provide a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron production. The accelerator complex consists of an H- injector capable of producing 38 mA peak current, a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The linear accelerator consists of a Drift Tube Linac, a Coupled-Cavity Linac and a Superconducting Linac which provide 1.5 mA average current to the accumulator ring. The staged beam commissioning of the accelerator complex is proceeding as component installation progresses. Recently, the normal-conducting linear accelerator was beam commissioned. A number of beam dynamics and beam quality measurements will be reported, including the measurement of transverse emittances in the H- injector, and the evolution of halo and emittance along the linac. |
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| FPAE076 | The System of Nanosecond 280-keV-He+ Pulsed Beam | ion, quadrupole, target, focusing | 3982 | ||
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Funding: We would like to acknowledge the support of the Thailand Research Fund, the National Research Council of Thailand, the Thai Royal Golden Jubilee Scholarship Program, the Faculty of Science, and the Graduate School of Chiang Mai University. |
At Fast Neutron Research Facility,the 150 kV-pulseds neutron generator is being upgraded to produce a 280-keV-pulsed-He beam for time-of-flight Rutherford backscattering spectrometry. It involves replacing the existing beam line elements by a multicusp ion source, a 400-kV accelerating tube, 45o-double focusing dipole magnet and quadrupole lens. The Multicusp ion source is a compact filament-driven of 2.6 cm in diameter and 8 cm in length. The current extracted is 20.4 μA with 13 kV of extraction voltage and 8.8 kV of Einzel lens voltage. The beam emittance has been found to vary between 6-12 mm mrad. The beam transport system has to be redesigned based on the new elements. The important part of a good pulsed beam depends on the pulsing system. The two main parts are the chopper and buncher. An optimized geometry for the 280 keV pulsed helium ion beam will be presented and discussed. The PARMELA code has been used to optimize the space charge effect, resulting in pulse width of less than 2 ns at a target. The calculated distance from a buncher to the target is 4.6 m. Effects of energy spread and phase angle between chopper and buncher have been included in the optimization of the bunch length. |
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| FPAT063 | Control System for the ORNL Multicharged Ion Research Facility High-Voltage Platform | ion, vacuum, controls, power-supply | 3591 | ||
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Funding: Work supported by U. S. DOE Office of Fusion Energy Sciences and Office of Basic Energy Sciences under contract No. DE-AC05-00OR22725 with UT-Battelle, LLC. |
A control system for the 250-kV platform and beamlines for accelerating and transporting multiply-charged ion beams produced by an all-permanent-magnet ECR ion source has been developed at the ORNL Multicharged Ion Research Facility. The system employs Experimental Physics and Industrial Control System (EPICS) software controlling an Allen-Bradley ControlLogix Programmable Logic Controller (PLC). In addition to the I/O control points of the PLC, other devices are controlled directly by the EPICS computer through RS-232 and GPIB interfaces. PLC chassis are located at each major electrical potential of the facility, that is, at the ECR source potential, at the platform potential, and at ground potential used in the beamlines transporting ions to the various experimental end-stations. Connection of the control system components to the EPICS host is accomplished via EtherNet, including fiber optic links to the HV platform. The user interface is designed with the Extensible Display Manager (EDM) software and custom applets perform such tasks as mass-to-charge ratio scans of the platform analyzing magnet and archival of source and beamline operating parameters. |
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| FOAB001 | Compact Neutron Generators for Medical, Home Land Security, and Planetary Exploration | ion, plasma, target, electron | 49 | ||
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Funding: This work is being support by U.S. Department of Energy under contract No. DE-AC03-76SF00098. |
The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced D-D (neutron energy 2.5 MeV), D-T (14 MeV) and T-T (0 – 9 MeV) neutron generators for wide range of applications. These applications include medical (Boron Neutron Capture Therapy), homeland security (Prompt Gamma Activation Analysis, Fast Neutron Activation Analysis and Pulsed Fast Neutron Transmission Spectroscopy) and planetary exploration in form of neutron based, sub-surface hydrogen detection systems. These neutron generators utilize RF induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Three main neutron generator developments are discussed here: high neutron output co-axial neutron generator for BNCT applications, point neutron generator for security applications, compact and sub-compact axial neutron generator for elemental analysis applications. Current status of the neutron generator development with experimental data will be presented. |
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| FOAB004 | Construction of FFAG Accelerators in KURRI for ADS Study | ion, acceleration, proton, booster | 350 | ||
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KART (Kumatori Accelerator driven Reactor Test) project is in progress at Kyoto University Research Reactor Institute (KURRI) from the fiscal year of 2002. The purposes of this project is the feasibility study of ADS, such as studying the effect of incident neutron energy on the effective multiplication factor of the subcritical nuclear fuel system. We are now constructing a proton FFAG accelerator complex as a neutron production driver for this project. Our accelerator complex consists of a 2.5 MeV FFAG with induction acceleration as an injector, 20 MeV and 150 MeV FFAGs with RF acceleration as a booster and a main ring, respectively. Our FFAG injector is a spiral sector type with 32 trim coils to produce a magnetic field of variable field index. Both booster and main rings are the radial sector type in which the field index is determined by the shape of pole-face. The test operations of the injector and the whole FFAG complex are expected around the spring and summer in 2005, respectively. Then this FFAG complex will be combined with our Kyoto University Critical Assembly (KUCA) in KURRI by the end of March 2006 for the feasibility study.
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| FOAB009 | The Frankfurt Funneling Experiment | rfq, ion, emittance, linac | 677 | ||
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Funding: BMBF |
Funneling is a technique to multiply beam currents of rf-accelerators in several stages at low energies to prevent problems with space charge. The Frankfurt Funneling Experiment is a prototype of such a stage. Two beams accelerated in a Two-Beam RFQ are combined to one beam axis with a funneling deflector. The last part of the RFQ electrodes of our Two-Beam RFQ has been replaced to achieve a 3d focus of both beams at the beam crossing point behind the RFQ in the center of the deflector. A newly designed multi cell funneling deflector and first results of the new experimental set-up will be presented. |
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