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  • 1
    Electronic Resource
    Electronic Resource
    The Frankfurt MEDEBIS: A prototype of an injector for a synchrotron dedicated for cancer therapya) : Proceedings of the 6th international conference on ion sources (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 1165-1167 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The Frankfurt MEDEBIS has been constructed to study the techniques of an electron beam ion source (EBIS) designed as an injector for a synchrotron dedicated to cancer therapy. The MEDEBIS uses a normal conducting solenoid of 0.8 T and a trap length of 0.25 m. The aims are to inject fully stripped light ions like C6+ and O8+ in a single turn into a synchrotron for the most simple and reliable operation. Therefore fast ion extraction in less than 4 μs has been examined, both theoretically and experimentally. The source complexity has been reduced by iron shielding of an electron gun and collector without any bucking coils. The electron gun operates with partially immersed flow focusing and provides a maximum current density of about 70 A/cm2. With a second anode the beam perveance is variable. The ion extraction time is reduced by a novel electrostatic structure providing a pulsed extraction field along the axis of the whole ion trap. Measurements of extracted ion pulses and the total number of extracted charges are presented. At confinement times of about 200 ms bare nuclei are obtained with maximum abundance in the charge spectra in good agreement with design data and Lotz cross sections. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146720
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  • 2
    Electronic Resource
    Electronic Resource
    A multipassage spectrometer for the study of electron–ion interactions in the EBIS : Proceedings of the fourth International Conference on Ion Sources (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 2817-2818 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A multipassage magnetic spectrometer has been constructed which allows selection of a specific high charge state from the extracted ion pulse of our electron beam ion source (EBIS) and to reinject it in the emptied source, now using the electron beam of meanwhile changed energy as a target of free electrons for the study of ionization, dielectronic recombination (DR), or radiative electron capture (REC). The spectrometer consists of a H-magnet with round pole pieces and 4 identical arrangements of achromatic lenses and mirrors under 90° forming a versatile ion switchyard with the possibility of recirculation. The chromaticity of the recirculating transport system and the dispersion of this spectrometer are adjustable by electric potentials on suitably placed electrostatic deflectors inside of the magnetic field. For the injection of ions from an external ion source into the EBIS and to the beam lines, the mirror potentials are pulsed accordingly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142815
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  • 3
    Electronic Resource
    Electronic Resource
    Status of the development of electron beam ion sources at Frankfurt : Proceedings of the 7th international conference on ion sources (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 718-720 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The Frankfurt superconducting electron beam ion source (EBIS) is under reconstruction for higher ion yield by employing an immersed gun with a 2-mm-diam cathode for a 3 A electron beam. The trap electrode construction is as simple as possible to avoid any rf production. The ion extraction will be similar to the one applied in our MEDEBIS, using tapered electrodes to create a high axial extraction gradient. Research was continued on the use of oscillating electrons to reduce the power requirements of the beam, investigating the formation of a virtual cathode by decelerating the beam at full magnetic field strength while operating the gun under immersed flow conditions with adjustable compression. The MEDEBIS has proven its quality and reliability for the application as an injector for a medically dedicated synchrotron. To improve its yield of bare nuclei, better vacuum conditions are provided by drilling out the inner windings of the warm solenoid to allow for the installation of higher vacuum conductance. After the successful presentation of our XEBIST principle that delivers highly charged ions as Ar18+ and Ba46+ we have now shown its application for the production of singly charged ions as an injector of metallic ions. Finally, an EBIS/T with an internal Penning trap has been constructed to prepare selected ion species and charge states inside the ionization region. This new device will allow the study of electron–ion interactions in well-defined initial and final charge states, i.e., to be able to distinguish between single and multiple step ionization. If the homogeneity of the magnetic field in the trap region will reach 10−9, the determination of binding energies of highly charged ions may be better than a 1 eV accuracy. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148560
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  • 4
    Electronic Resource
    Electronic Resource
    Frankfurt EBIS development: Fundamental research and new applications : Proceedings of 5th international conference on ion sources (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1069-1071 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Fundamental questions of electron beam ion sources (EBIS) are studied using three different setups. Cryogenic classical EBIS: The limit of ion–ion cooling in EBIS devices operating near the space-charge neutralization limit has been studied experimentally. To investigate different degrees of compensation of the electron beam by highly charged ions, a hemispherical analyzer has been constructed including a novel deceleration optic for high resolution. Using its energy definition we tested different modes of ion transportation in our multipassage magnetic spectrometer, which can be operated chromatically as well as extremely dispersively: up to 200 passages could be obtained. EBIS without magnetic field: First results on ion production in the short trap at the very dense crossover of an electron beam (XEBIS) confined only inertially without the use of magnetic fields are presented. Normal conducting short EBIS: Using a normal conducting field of 0.8 T of 25-cm length an EBIS is under construction to study extremely short ion extraction of approximately 4 μs for single turn injection into a medical synchrotron for cancer therapy (MEDEBIS).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145065
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  • 5
    Electronic Resource
    Electronic Resource
    Space-charge compensation of electron beams by thermal ions and the production of highly charged ions in EBIS and EBIT : Proceedings of 5th international conference on ion sources (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1063-1065 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The space-charge compensation of electron beams by hot ions with a Boltzmann energy distribution has been investigated by solving Poisson's equation. A unique relation is obtained between the degree of central compensation and the ion temperature: At high temperatures (as compared to the potential depression inside the beam) the compensation is low and the ions stay inside the electron beam only to a minor part, while at low ion temperatures, the beam is almost fully compensated. The potential difference between the beam axis and the surrounding tube is reduced by compensation, but when measured in terms of the temperature of compensating ions, it increases. This shall better confine the ions to the electron beam, the more complete the compensation. Increasing with the square of their charge state, trapped ions are heated by the ionizing beam electrons through small angle Coulomb collisions. For different ions with different charge states, the almost compensated electron beam acts as an energy filter, where the hotter ions are lost radially or axially. Therefore highly charged ions, which became "hot'' by waiting for stepwise ionization, can be cooled by lower charged ones, which still are "cold.'' This phenomenon has been called "evaporative cooling'' in electron beam ion sources (EBIS) and traps (EBIT) and space-charge compensation of the electron beam is the driving physic for it.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145063
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  • 6
    Electronic Resource
    Electronic Resource
    An EBIS/RFQ−Injector for a cancer therapy synchrotron : Proceedings of the fourth International Conference on Ion Sources (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 2812-2814 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The electron beam ion source (EBIS) is an intense source of bare nuclei of light elements (C,N,O,Ne) for short pulses. A fast extraction time of 4 μs allows advantageous single turn injection into a medically dedicated synchrotron. Since the EBIS can provide bare nuclei of all light ions, it combines favorably with a 1.8 m long radio-frequency-quadrupole accelerator (RFQ) as the only LINAC needed for an injection energy of 1 MeV/u. The required intensity of 108 ions per pulse in 1 s is easily exceeded by a factor of 10 to compensate for beam losses. The technology of an EBIS with an electron current of 165 mA at 3 keV and 50 A/cm2 is well established and has proven to be very reliable for synchrotron injection over many years in Dubna, Saclay, and Stockholm. The low duty factor (10−4) of the RFQ, where 250 kW pulses of rf power will be applied for 25 μs, eliminates the need for cooling. Therefore a four-rod structure may be put on ceramic stands, biased with a negative high voltage to avoid high voltage on the source. The combination of an EBIS with a short RFQ may be considered as the least complex and most reliable injector solution for filling a cancer therapy synchrotron with fully stripped light ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142813
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  • 7
    Electronic Resource
    Electronic Resource
    The ion cooling in EBIS : Proceedings of the fourth International Conference on Ion Sources (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 2819-2821 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The article is devoted to the problems of heating and cooling of highly charged ions in EBIS. The loss rates for ions with the Boltzmann distribution function of energies for different ionic species are determined. The results suggest the use of the lightest possible ions for ion cooling. Continuous flow of light ions is proposed for cooling. The necessary parameters of light ion flow are defined in the article.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142816
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  • 8
    Electronic Resource
    Electronic Resource
    Study of the feasibility of self focusing of a relativistic electron beam in an electron beam ion source/trap : Proceedings of the 7th international conference on ion sources (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 691-693 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: With electron beam ion sources/traps (EBIS/T) ions with highest charge states can be produced. EBIT represents a successful device for atomic physics studies, while EBIS is also an injector to accelerate highly charged ions of every species. High performance EBIS/T usually uses a high magnetic field generated by superconducting coils to compress the electron beam, in order to obtain high electron beam current densities in the range of 102–103 A/cm2 along the ionization region. Studies on a crossover (X-) EBIS without magnetic field but using an electrostatically generated electron beam crossover have shown the production of highly charged ions like Ar18+ and Ba46+. A project was started to yield high current densities from the self pinching of a relativistic electron beam in a partially space charged compensated region. A 65 keV electron beam is produced by a high emissive cathode with the lowest possible beam emittance and is focused by magnetic lenses into the trap region, where the electronic space charge will be compensated by trapped ions. The current density produced by the crossover will be enhanced by the self pinching of the relativistic electron beam. Axial ion extraction optics and radial diagnostics in the ReXEBIST (relativistic XEBIS/T) allow both, EBIS and EBIT operation. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148554
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  • 9
    Electronic Resource
    Electronic Resource
    A generation of unconventional electron beam ion sources : Proceedings of the 6th international conference on ion sources (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 986-988 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: While a high electron current electron beam ion source (EBIS) with high perveance has been proposed for its application at forthcoming TeV hadron colliders, an economical operation has been studied using oscillating electrons to reduce the collector current for low power consumptions. Results with oscillating electrons in our cryogenic EBIS with a 5 T magnetic focusing field are being discussed in relation to normal EBIS operation data considering the oscillation factor, current density, and ion yield. Our simplified EBIS/EBIT studies without magnetic focusing now span from a versatile source for the production of high current singly charged metallic ions up to the use of relativistic electron beams for the production of bare uranium. The XEBIST now works successfully with beam energies up to 10 keV. Barium ions having a charge state up to 46 have been extracted using evaporative cooling by Ar and residual gas. The extension to relativistic beam energies taking advantage of the self-focusing effect at partial space charge compensation will be presented elsewhere at this conference. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146790
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  • 10
    Electronic Resource
    Electronic Resource
    A design study for a super-EBIT/EBIS without magnetic fielda) : Proceedings of the 6th international conference on ion sources (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 983-985 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A super-EBIT may be defined by its ability to ionize even hydrogenlike uranium, requiring an electron energy well above 140 keV. The first super-EBIT has been put into operation at Livermore, operating with electron energies up to 200 keV, the second one is in progress in Tokyo, aiming at 300 keV. A distinctive advantage may be obtained by raising the electron energy from 200–300 to 500 keV, thus reducing the radiative recombination of hydrogenlike heavy ions such as U91+ and increasing their relative abundance by an order of magnitude. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146789
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