摘要:

Electron Cyclotron Resonance (ECR) ion sources are used for many applications, ranging from the production of high intensity proton beams to the production of high charge state ion beams. This review is focused on the production of ions for heavy ion accelerators, which take advantage of the high reliability and stability of the beams produced by ECR ion sources as well as of their capability to produce currents in the order of some e&mgr;A of fully stripped light ions and of high charge states heavy ions. The improvement of performance through the years has been steady and an energy increase of the accelerated beams has followed. A brief summary of the main breakthroughs will be given, as the gas mixing and the electron donors. The role of the magnetic field and frequency will be described with a particular attention to the High B mode concept and to the method of multiple frequency injection. Some future developments that will increase the currents of the highest charge states and the design of some “3rd generation ECR ion sources” will be considered in the following. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58950

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

High charge states, up to fully stripped11Cand14Oion, beams have been produced with the electron cyclotron resonance ion sources (LBNL ECR and AECR-U) at Lawrence Berkeley National Laboratory. The radioactive atoms of11Cand14Owere collected in batch mode with anLN2trap and then bled into the ECR ion sources. Ionization efficiency as high as 11&percent; for11C4+was achieved. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58951

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

New techniques for enhancing the performances of electron cyclotron resonance (ECR) ion sources are being investigated at the Oak Ridge National Laboratory. We have utilized the multiple discrete frequency technique to improve the charge state distributions extracted from conventional magnetic field geometry ECR source by injecting three frequencies into the source. A new flat central magnetic field concept, has been incorporated in the designs of a compact all-permanent-magnet source for high charge-state ion beam generation and a compact electromagnetic source for singly ionized radioactive ion beam generation for use in the Holifield Radioactive Ion Beam Facility (HRIBF) research program. A review of the three frequency injection experiments and descriptions of the design aspects of the “volume-type” ECR ion sources will be given in this report. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58952

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Chemically active radioactive species, diffused from RIB target materials, often arrive at the ionization chamber of the source in a variety of molecular forms. Because of the low probability for simultaneously dissociating and efficiently ionizing the individual atomic constituents of molecules with conventional hot-cathode electron-impact ion sources, the species of interest are often distributed in several mass channels in the form of molecular side-band beams and consequently, their intensities are diluted. The sputter negative ion beam generation technique offers an efficient means for simultaneously dissociating and ionizing highly electronegative atomic species present in molecular carriers. We have incorporated these principles in the design and fabrication of a kinetic ejection negative ion source and evaluated its potential for generating17,18F−beams for the Holifield Radioactive Ion Beam Facility astrophysics research program. The source utilizesCs+beams to bombard condensable fluorine compounds that emanate from a target material, such asAl2O3,and are transported to the cooled inner surface of a conical-geometry cathode where they are adsorbed. The energeticCs+beams efficiently dissociate these molecules and sputter their constituents. Since the work functions of cesiated surfaces are low, highly electronegative species such as fluorine are efficiently ionized in the sputter-injection process. Measured efficiencies for ionizing atomic fluorine, dissociated from condensable compounds that are formed by reactions ofSF6with fibrousAl2O3material, exceed 6.5&percent;. In this report, we describe the mechanical design features and principles of operation, and present emittance,F−yield and ionization efficiency data derived from off-line, experimental evaluation of the source. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58953

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

A high-intensity, plasma-sputter negative-ion source based on the use of RF power for plasma generation has been developed that can be operated in either pulsed ordcmodes. The source utilizes a high-Q, self-igniting, inductively coupled antenna system, operating at 80 MHz that has been optimized to generate Cs-seeded plasmas at low pressures (typically, <1 mTorr for Xe). The source is equipped with a 19-mm diameter spherical-sector cathode machined from the desired material. To date, the source has been utilized to generatedcnegative-ion beams from a variety of species, including:C−(610&hthinsp;&mgr;A);F−(100&hthinsp;&mgr;A);Si−(500&hthinsp;&mgr;A);S−(500&hthinsp;&mgr;A);P−(125&hthinsp;&mgr;A);Cl−(200&hthinsp;&mgr;A);Ni−(150&hthinsp;&mgr;A);Cu−(230&hthinsp;&mgr;A);Ge−(125&hthinsp;&mgr;A);As−(100&hthinsp;&mgr;A);Se−(200&hthinsp;&mgr;A);Ag−(70&hthinsp;&mgr;A);Pt−(125&hthinsp;&mgr;A);Au−(250&hthinsp;&mgr;A).The normalized emittance&Vegr;nof the source at the 80&percent; contour is:&Vegr;n=7.5&hthinsp;mm.mrad.(MeV)1/2.The design principles of the source, operational parameters, ion optics, emittance and intensities for a number of negative-ion species will be presented in this report. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58954

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

A multi-sample Cs sputter negative-ion source, equipped with a conical-geometry, W-surface-ionizer has been designed and fabricated that permits sample changes without disruption of on-line accelerator operation. Sample changing is effected by actuating an electro-pneumatic control system located at ground potential that drives an air-motor-driven sample-indexing-system mounted at high voltage; this arrangement avoids complications associated with indexing mechanisms that rely on electronic power-supplies located at high potential. In-beam targets are identified by LED indicator lights derived from a fiber-optic, Gray-code target-position sensor. Aspects of the overall source design and details of the indexing mechanism along with operational parameters, ion optics, intensities, and typical emittances for a variety of negative-ion species will be presented in this report. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58955

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

The design and development of the supervisory and control system for an Electron Cyclotron Resonance (ECR) Ion Source at Laboratori Nazionali di Legnaro (LNL) are described. Both the hardware and the software architectures of the system are presented, together with its links with the control systems of the superconducting linear accelerator ALPI and of the new injector PIAVE. A number of different control devices and instruments for measurements are used in the ECR, and this feature forced the integration in the same system of both traditional home-made available hardware/software solutions and of commercial products for standard industrial control systems. The new control system for the ECR Ion Source is planned to be put into operation in some months. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58956

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

The Legnaro ECR ion source is installed on high voltage platform, capable of operating up to 350 kV and to be powered by an externally located insulation transformer. The test of the prototype of the high voltage cable termination is described, together with design of the full size cable termination. Tests of other high voltage parts are described. In the extraction beamline from the platform a triplet was added after the acceleration column, so that injection in the following U-bend is simplified. Using empirical fitting formula for prediction of einzel lens cardinal data and perturbative expansion for triplets, understanding of beam lines was considerably improved and optimization for arbitrary ions were possible. A comparison of the performance of the several plasma chambers that were used in this ECR ion source is given, discussing also the effect of a low voltage sputter probe. A comprehensive software program, centralizing remote control of most platform and source regulation, was successfully tested. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58957

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

When the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory is completed in 1999, the Tandem Van de Graaff, using cesium sputter sources, will produce the gold ions. The sputter sources are operated in a unique pulsed beam mode that allows the injection into the tandem of 200 to 300 &mgr;Amps of negative ions for up to 2 msec. This is several orders of magnitude higher instantaneous current than is possible in the direct current mode. These high current pulses have severe problems with space charge forces. The research to overcome the space charge forces has resulted in a 500 &mgr;sec pulse containing9×109ions after acceleration in the tandem. This a three fold increase in intensity in the last three years. There is also growing interest in other ion species specifically iron, silicon, and uranium. The research to produce useable quantities of these ions is also presented. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58958

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

A design study for the extraction system of the 3rd Generation super conducting ECR ion source at LBNL is presented. The magnetic design of the ion source has a mirror field of 4 T at the injection and 3 T at the extraction side and a radial field of 2.4 T at the plasma chamber wall. Therefore, the ion beam formation takes place in a strong axial magnetic field. Furthermore, the axial field drops from 3 T to 0.4 T within the first 30 cm. The influence of the high magnetic field on the ion beam extraction and matching to the beam line is investigated. The extraction system is first simulated with the 2D ion trajectory code IGUN with an estimated mean charge state of the extracted ion beam. These results are then compared with the 2D code AXCEL-INP, which can simulate the extraction of ions with different charge states. Finally, the influence of the strong magnetic hexapole field is studied with the three dimensional ion optics code KOBRA. The introduced tool set can be used to optimize the extraction system of the super conducting ECR ion source. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58959

出版商:AIP    

年代:1999

数据来源: AIP