43 research outputs found
Anisotropy of Alfvénic Turbulence in the Solar Wind and Numerical Simulations
No full text10.12.13 KB. Ok to add published version to spiral, RAS/OUP polic
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Next generation ECR ion sources: First results of the superconducting 28 GHz ECRIS - VENUS
No full textVENUS (Versatile ECR ion source for NUclear Science) is a next generation superconducting ECR ion source, designed to produce high current, high charge state ions for the 88-Inch Cyclotron at the Lawrence Berkeley National Laboratory. VENUS also serves as the prototype ion source for the RIA (Rare Isotope Accelerator) front end.The goal of the VENUS ECR ion source project as the RIA R&D injector is the production of 200 mu A of U30+, a high current medium charge state beam. On the other hand, as an injector ion source for the 88-Inch Cyclotron the design objective is the production of 5e mu A of U48+, a low current, very high charge state beam. To achieve those ambitious goals, the VENUS ECR ion source has been designed for optimum operation at 28 GHz. The nominal design fields of the axial magnets are 4T at injection and 3T at extraction; the nominal radial design field strength at the plasma chamber wall is 2T, making VENUS currently the world most powerful ECR plasma confinement structure.Recently, the six year project has made significant progress. In June 2002, the first plasma was ignited at 18 GHz. During 2003, the VENUS ECR ion source was commissioned at 18 GHz, while preparations for 28 GHz operation were being conducted. In May 2004 28 GHz microwave power has been coupled into the VENUS ECR ion source for the first time. Preliminary performance-tests with oxygen, xenon and bismuth at 18 GHz and 28 GHz have shown promising results. Intensities close to or exceeding the RIA requirements have been produced for those few test beams.The paper will briefly describe the design of the VENUS source and its beam analyzing system. Results at 18 GHz and 28 GHz including first emittance measurements will be described
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High Intensity Ion Beam Injection Into the 88-Inch Cyclotron
No full textLow cross section experiments to produce super-heavyelements have increased the demand for high intensity heavy ion beams atenergies of about 5 MeV/nucleon at the 88-Inch Cyclotron at the LawrenceBerkeley National Laboratory. Therefore, efforts are underway to increasethe overall ion beam transmission through the axial injection line andthe cyclotron. The ion beam emittance has been measured for various ionmasses and charge states. Beam transport simulations including spacecharge effects were performed for both of the injection line and the ionsource extraction. The relatively low nominal injection voltage of 10 kVwas found to be the main factor for ion beam losses, because of beam blowup due to space charge forces at higher intensities. Consequently,experiments and simulations have been performed at higherinjectionenergies, and it was demonstrated that the ion beams could still becentered in the cyclotron at these energies. Therefore, the new injectorion source VENUS and its ion beam transport system (currently underconstruction at the 88-Inch Cyclotron) are designed for extractionvoltages up to 30 kV
Rediscovering a Lost Alchemical Text: The Risālat Mītāwus al-‘uẓmā
No full textIn 1971 and 1972, Fuat Sezgin and Manfred Ullmann drew attention to a peculiar alchemist mentioned in various texts, a certain Mītāwus, but whose works had not been preserved. Sezgin saw in the name of this character a corruption of the name of the alchemist Petasios, and Ullmann, more likely, a transcription of the name Matthaeus. In this paper, the author will present a text by this author that he found in an Iranian manuscript, and discuss its content and its attribution
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Development of a high intensity 48Ca ion beam for the heavy element program
No full textA high intensity {sup 48}Ca ion beam has been developed at the 88 Inch Cyclotron for the synthesis of {sup 283}112 using the reaction {sup 238}U({sup 48}Ca, 3n). An ion beam intensity of {approx} 700 pnA was delivered on target, resulting in a total dose of 2 x 10{sup 18} ions over a six day period. Since {sup 48}Ca is a very expensive and rare isotope minimal consumption is essential. Therefore a new oven [1] and special tantalum liner [2] have been developed for the AECR-U ion source during the last year to improve the metal ion beam efficiency. Both the LBL ECR and the AECR-U ion sources are built with radial access. Six radial slots between the sextupole magnet bars provide additional pumping and easy access to the plasma chamber for ovens and feedthroughs. Two types of radial ovens have been used at LBNL in the past, operating at temperatures up to 2100 C
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Solenoidal Fields for Ion Beam Transport and Focusing
No full textIn this report we calculate time-independent fields of solenoidal magnets that are suitable for ion beam transport and focusing. There are many excellent Electricity and Magnetism textbooks that present the formalism for magnetic field calculations and apply it to simple geometries [1-1], but they do not include enough relevant detail to be used for designing a charged particle transport system. This requires accurate estimates of fringe field aberrations, misaligned and tilted fields, peak fields in wire coils and iron, external fields, and more. Specialized books on magnet design, technology, and numerical computations [1-2] provide such information, and some of that is presented here. The AIP Conference Proceedings of the US Particle Accelerator Schools [1-3] contain extensive discussions of design and technology of magnets for ion beams - except for solenoids. This lack may be due to the fact that solenoids have been used primarily to transport and focus particles of relatively low momenta, e.g. electrons of less than 50 MeV and protons or H- of less than 1.0 MeV, although this situation may be changing with the commercial availability of superconducting solenoids with up to 20T bore field [1-4]. Internal reports from federal laboratories and industry treat solenoid design in detail for specific applications. The present report is intended to be a resource for the design of ion beam drivers for Inertial Fusion Energy [1-5] and Warm Dense Matter experiments [1-6], although it should also be useful for a broader range of applications. The field produced by specified currents and material magnetization can always be evaluated by solving Maxwell's equations numerically, but it is also desirable to have reasonably accurate, simple formulas for conceptual system design and fast-running beam dynamics codes, as well as for general understanding. Most of this report is devoted to such formulas, but an introduction to the Tosca{copyright} code [1-7] and some numerical results obtained with it are also presented. Details of design, fabrication, installation, and operation of magnet systems are not included; here we are concerned with calculations that precede or supplement detailed design. Mathematical derivations are presented with only a moderate number of steps. While there is no claim of originality, except for various numerical approximations and a conceptual induction module design in section 20, many of the results and discussions are not readily available elsewhere. Our primary topic is axisymmetric solenoidal systems with no magnetic materials. These simplifying features allow useful analytical calculations, which occupy sections 2-13. Deviations from axisymmetry are considered in sections 14, 15, 21, 22, and 23 and the effects of magnetic materials are treated in sections 16-20. Since magnetic aberrations are mixed with geometric aberrations in computing ion orbits, section 22 on the ion equations of motion in an arbitrary field is included
Calendarium naturale magicum perpetuum profundissimam rerum secretissimarum contemplationem totiusque Philosophiæ cognitionem complectens [graphic].
No full textThe print depicts and describes a hermetic universe, with fourteen horizontal parts, each subdivided vertically into a number of sections connecting with others. The print incorporates alchemical, astrological and mystical elements.Ref.: Magic, alchemy and science 15th-18th centuries : the influence of Hermes Trismegistus, ed. Carlos Gilly, Cis van Heertum. Florence: Centro Di, 2002; The magical calendar: a synthesis of magical symbolism from the seventeenth century renaissance of medieval occultism, ed. Adam McLean. Edinburgh: Magnum Opus, Hermetic Sourceworks, 1979.Cf. Gilly: the reference to Tycho Brahe as inventor implies only that the Calendarium imitates the method employed by the Danish astronomer.Print lacking date, attributed to Matthaeus Merian after images and text by Johann Baptist Grossschedel von Aicha.Print with letters: Auth. Iohan Babtista [Gro]ssschedel ab Aicha; Io. Theodore de Bry excudeb.; Thico Brahae inuentor 1582.Three sheets joined on linen mount.The print depicts and describes a hermetic universe, with fourteen horizontal parts, each subdivided vertically into a number of sections connecting with others. The print incorporates alchemical, astrological and mystical elements.Mode of access: Internet.mlanAssessed: Condition report in research file
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Design of the extraction system and beamline of the superconducting ECR ion source VENUS
No full textA new, very high magnetic field superconducting ECR ion source, VENUS, is under construction at the LBNL 88-Inch Cyclotron [1,2]. The paper describes the VENUS extraction system and discusses the ion beam formation in the strong axial magnetic field (3 T) of the ECR ion source. Emittance values as expected from theory, which assumes a uniform plasma density across the plasma outlet hole, are compared with actual measurements from the AECR-U ion source. Results indicate that highly charged heavier ions are concentrated on the source axis. They are extracted from an ''effective'' plasma outlet hole, whose smaller radius must be included in ion optics simulations
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Progress report on VENUS
No full textThe construction of VENUS, a next generation superconducting Electron Cyclotron Resonance ion source designed to operate at 28 GHz, is complete. The cryostat including the superconducting magnet assembly was delivered in September 2001. During acceptance tests, the superconducting magnets produced an axial magnetic field strength of 4T at injection, 3T at extraction, and a radial field strength of 2T at the plasma chamber wall without any quenches. These fields are sufficient for optimum operation at 28 GHz. The cryogenic system for VENUS has been designed to operate at 4.2 K with two cryocoolers each providing up to 45 W of cooling at 50 K and 1.5 W at 4 K in a closed loop mode without further helium transfers. However, during the acceptance tests an excessive heat leak of about 3W was measured. In addition, the liquid helium heat exchanger did not work properly and had to be redesigned. The cryogenic system modifications will be described. In addition, an update on the installation of the ion source and its beam line components will be given
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High intensity metal ion beam production with ECR ion sources
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