ANL, Argonne
Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
Construction of the DOE Californium Rare Ion Breeder Upgrade (CARIBU) for the ATLAS facility is expected to be completed by the end of 2008 and commissioning should be well along by the time of the conference. The facility will use fission fragments from a 1 Ci 252Cf source, thermalized and collected into a low-energy particle beam by a helium gas catcher, mass analyzed by an isobar separator, and charge breed to higher charge states for acceleration in ATLAS. In addition, unaccelerated beams will be available for trap and laser probe studies. Expected yields of accelerated beams are up to ~5x105 (107 to traps) far-from-stability ions per second on target. The facility design and first results of beam acceleration using a weaker 80 mCi source will be presented in this paper and plans for installation of the 1 Ci source will be discussed.
LBNL, Berkeley, California
Third generation Electron Cyclotron Resonance (ECR) ion sources operate at rf frequencies between 20 and 30 GHz and employ NbTi superconducting magnets with a conductor peak field of 6-7 T. A significant gain in performance can be achieved by replacing NbTi with Nb3Sn, allowing solenoids and sextupole coils to reach a field of 15 T in the windings. In this paper we describe the design of a Nb3Sn superconducting magnet for a fourth generation ECR source operating at a rf frequency of 56 GHz. The magnet design features a configuration with an internal sextupole magnet surrounded by three solenoids. A finite element magnetic model has been used to investigate conductor peak fields and the operational margins. Results of the numerical analysis are presented and discussed.
INFN/LNS, Catania
During the last 10 years it was demonstrated that slight variations of microwave frequency used in ECRIS strongly influence their performances either for extracted current and for beam brightness and stability. Theoretical investigations put in evidence that such frequency tuning is linked to the electromagnetic field structure inside the resonant cavity. On this basis, we carried out PIC simulations, showing that the frequency tuning has a global influence on plasma properties and on beam brightness. Such analysis allowed the design of the optimum setup for plasma chamber dimensions and microwave injection, to achieve higher currents and better emittances. The magnetic field is based on the use of steep gradient but the cryogenics issues are simplified; the extraction system is designed to minimize the aberrations. The overall dimensions of the MISHA source (Multicharged Ion Source for HAdrontherapy) have been chosen as a compromise between the ideal size for microwave to plasma interaction, the need to get long ion confinement time and the request of getting a compact ECRIS. The description of the source design will be given, along with the expected performances.
INFN/LNS, Catania
The trend of ECRIS to higher frequencies and magnetic fields is driven by the need to have higher beam currents and higher charge states for nuclear physics accelerators. Anyway, because of the limits imposed by the magnets’ and microwaves generator’s technology, any further increase of performances requires a detailed investigation of the plasma dynamics. The experiments have shown that the current, the charge states and even the beam shape change by slightly varying the microwave frequency (frequency tuning effect - FTE). Moreover, for last generation ECRIS, electron energies up to 2 MeV have been detected, depending mainly on the magnetic field structure and gradient distribution over the ECR surface. The plasma dynamics have been studied by means of single particle and PIC simulations: they explain the FTE in terms of the wave field distribution over the ECR surface and the existence of high energy electrons due to diffusion in the velocity space above the stochastic barrier. Other methods used to improve the ECRIS performances, e.g. the two frequency heating with an adequate phase relation between the two waves, can be exploited by means of the simulations.
Kyoto ICR, Uji, Kyoto
We are aiming to develop a compact accelerator based neutron source using Li(p,n) reaction. The first target is a small and high current H+ ion source as an injector of the neutron source. The demands are not only being small and high current but also longer MTBF and large ratio of H+ to molecular ions such as H2+ or H3+. Therefore, the ECR ion source with permanent magnets is selected as such an ion source. Because ECR ion sources don't have hot cathodes, longer MTBF is expected. Furthermore, they can provide high H+ ratio because of their high electron temperature. Using permanent magnets makes the ion source small and running cost low. Up to now, we have measured ion beam current on the first model of the ECR ion source, and fabricated the redesigned model. The data measured of the second model will be presented.
NSCL, East Lansing, Michigan
Funding: Supported by the National Science Foundation under grant PHY-0110253
The construction of the SUperconducting Source for Ions (SUSI), a 3rd generation Superconducting ECR ion source for the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University has been completed and commissioning of the source is ongoing. SUSI operates primarily at 18GHz and is scheduled to replace the 6.4 GHz SC-ECR for injection in the coupled cyclotron later this year. Excellent performances during commissioning have been obtained with SUSI for the production of highly charged ions for both metallic and gas elements and will be presented. A set of six solenoid coils gives SUSI the capability to modify the length and the position of the resonant zone and also to adjust the gradient of the axial magnetic field near the resonance. The impact of this flexible magnetic field profile on the ion beam production and the charge state distribution is actively studied and will be discussed. Emittance measurements of the ion beam extracted from SUSI have been performed and will also be presented.
UCBL, Villeurbanne
IN2P3 IPNL, Villeurbanne
DIAM is a new experimental system created for study the processes initiated by protons impact upon clusters of biomolecules especially the mechanism resulting from ionization and fragmentation in a complex molecular nanosystem. The experimental setup is designed to analyse interactions of two beams: on the one hand, protons from an ECR source are accelerated and guided into a monochromatic beam of 20 to 150 kV and 1mA. On the other hand, a cluster source is mounted on a high tension plat-form (5 to 30 kV). In order to analyse the products of protons/cluster interaction of the 2 crossing beams, we use several detection system such as Electro spray Time of Flight (ESI-TOF) or mass spectrometers.
LBNL, Berkeley, California
Funding: This work was supported by DOE and NSA.
The integration of scanning probes with ion beams enables non-destructive, nanometer scale imaging and alignment of ion beams to regions of interest in to be implanted device structures. We describe our basic approach which uses piezo-resistive force sensors and pierced cantilvers as dynamic shadow masks, integtrated with low current (<1 mA), low energy (<1 MeV) ion beams from a series of ion sources (ECR and EBIT). Single ion sensing strategies based on charge transients induced in devices and detection of secondary electrons are discussed. We will show results form our studies of single ion doping of 50 nm scale transistors in tests of radiation response mapping of transistors with this technique.
NSCL, East Lansing, Michigan
Funding: Michigan State University
The National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) is implementing a system called the ReA3 to reaccelerate rare isotope beams from projectile fragmentation to energies of about 3 MeV/u. The 80.5 MHz triple-harmonic buncher before the ReA3 Radio Frequency Quadrupole (RFQ) linac has recently been implemented and measurements made. Tests using beams from the Electron Cyclotron Resonance (ECR) ion source test stand are being performed. The beam properties after the buncher are fully characterized using various diagnostic tools (e.g. fast Faraday cup, energy analyzer, emittance scanner). As a result, the tuning procedures for the buncher operations are developed. We will present the detailed results of the beam based buncher studies and compare them with simulations.
RIKEN Nishina Center, Wako
Significant progress has been achieved since first ECR ion source was developed more than three decades ago and it became one of the best ion sources for heavy ion accelerators in the world. Such progress has been mainly due to utilization of higher microwave frequency and stronger magnetic confinement, technical innovations, and understanding of the production mechanisms of highly charged heavy ions in ECR plasma. Especially, in the last decade, the progress is strongly dependent on advances in the superconducting magnet technology and understanding of the Physics of ECR plasma. Very recently, as the interest in the radioactive beam for research in various fields grows, the need for more intense beam of highly charged heavy ions to inject into the accelerator requires new innovation to improve the ECR ion source performance. In this contribution, I will present the progress of the technology and physics of ECR ion sources. Based on these results, the concepts for next generation ECR ion source for meet the requirements will be presented.
Far-Tech, Inc., San Diego, California
ANL, Argonne
Funding: This work is supported by the US DOE SBIR program
GEM, developed by FAR-TECH Inc, is a self consistent hybrid code to simulate general ECRIS plasma. It calculates EDF (electron distribution function) using a bounce-averaged Fokker-Planck code and calculates the ion flow using a fluid code, which has been modified to implement new boundary settings including fixed boundary ion velocities or fixed sheath potentials at both ends of the device. Extensive studies on the convergence and performance of the code have been performed. Also, GEM has been connected to MCBC (Monte Carlo beam capture) code and the validations of the code using ANL ECR-I charge breeding data and other published experiments are underway. The typical converged solutions of GEM and the comparisons with the experiments will be presented and discussed.
GANIL, Caen
The SPIRAL 2 superconducting linac is currently under construction. This talk describes the collaboration effort with industrial partners to fabricate the two cryomodule families: the low beta Cryomodule A, and the high beta Cryomodule B. The low beta family is composed of 12 single cavity cryomodules. The high energy section is composed of 7 cryomodules hosting 2 cavities each. The design goal for the accelerating field Eacc of the SPIRAL 2 QWRs is 6.5 MV/m.
IAP, Frankfurt am Main
GSI, Darmstadt
A new CW-RFQ will be built for the upgrade of the HLI (High Charge State Injector) of GSI for operating with a 28 GHz-ECR-Ion source and simultaneous increase of the beam duty cycle from 25% 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 The design had been optimized to get a rather short structure with LRFQ=2m to match the available RF-power of max. 60 kW in cw. High beam transmission, a small energy spread and small transverse emittance growth and good input matching were design goals. Properties of this CW-RFQ and status of project will be presented.
JINR, Dubna, Moscow Region
The current status of the JINR FLNR cyclotrons and plans of their modernization are reported. At present time, four isochronous cyclotrons: U400, U400M, U200 and IC100 are under operation at the JINR FLNR. The U400 and the U400M are the basic cyclotrons that are under operation about 6000 and 3000 hours per year correspondingly. Both the accelerators are used in DRIBS experiments to produce and accelerate exotic very neutron-rich isotopes of light elements such as 6He and 8He. The U400 (pole diameter of D=4 m) is designed to accelerate ion beams of atomic masses from 4 to 209 to maximum energy of 26 MeV/u for synthesis of the new super heavy elements and other physical experiments. The U400M cyclotron (D=4 m) is used to accelerate ions of elements from Li to Ar up to 50 MeV/u and heavier ions such as 48Ca, Kr,Xe, up to 6 MeV/u after recent modernization. The U200 cyclotron (D=2 m) is used to produce isotopes by using He ions with energies about 9 MeV/u, modernization of the cyclotron injection is planned. Modernized IC100 accelerator (D=1m) is used to produce track membranes and carrying out experiments in solid-state physics by using Ar, Kr and Xe ions at energies of 1.2 MeV/u.