Author: Droba, M.
Paper Title Page
MOPAB039 Development of a Control System Based on Experimental Data for Space Charge Lenses 166
 
  • S. Klaproth, C. Beberweil, M. Droba, O. Meusel, H. Podlech, B.E.J. Scheible, K. Schulte, K.I. Thoma, C. Wagner
    IAP, Frankfurt am Main, Germany
 
  Space charge lenses use a confined electron cloud for the focusing of ion beams. The electron density gives the focusing strength whereas the density distribution influences the mapping quality of the space charge lens and is related to the confinement. The major role of the electron density with respect to the focusing quality has been pointed out many times in the past *,**. With an automated measurement system the radial light density profile, plasma stability and mean value of the electron density have been measured in respect to the confining fields and the pressure. The results are summarized in 3D-maps. The theoretical model approximations for space charge lenses predicts high electron densities then measured. With the automated system the realistic 3D-maps can be considered instead of an approximation of a theoretical density including knowledge of the most stable electron cloud achievable within the parameter range of the lens. The experimental results of the automated measurement system will be presented here and a concept of a control system for this type of space charge lenses will be explained.
* O. Meusel, 'Focussing and transport of ion beams using space charge lenses', PhD thesis, 2006
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB039  
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MOPIK067 Figure-8 Storage Ring - Ion Beam Injection into a Closed, Magnetic System 680
 
  • H. Niebuhr, A. Ates, M. Droba, O. Meusel, U. Ratzinger
    IAP, Frankfurt am Main, Germany
 
  To store high current low-energetic ion beams of up to 10 A, a superconducting storage ring (F8SR) based on solenoidal and toroidal magnetic guiding fields is investigated at Frankfurt University. Besides simulations, a scaled down experimental setup with normalconducting magnets was built. Investigations of beam injection into closed, magnetic guiding fields are in progress. Therefore, a new kind of injection system consisting of a solenoidal injection coil and a special vacuum vessel was constructed. It is used to inject a hydrogen beam from the side between two toroidal magnets. In parallel operation, a second hydrogen beam is transported through both magnets to represent the circulating beam. The current status of the experimental setup and first experimental results will be shown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK067  
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THPVA005 Investigation of Electron Beam Assisted Density Boosting in Plasma Traps Using the Example of a Gabor Plasma Lens 4421
 
  • C. Beberweil, M. Droba, S. Klaproth, O. Meusel, D. Noll, H. Podlech, K. Schulte, K.I. Thoma
    IAP, Frankfurt am Main, Germany
  • S. Gammino, D. Mascali
    INFN/LNS, Catania, Italy
  • L. Malferrari, A. Montanari, F. Odorici
    INFN-Bologna, Bologna, Italy
 
  Gabor lenses are plasma traps that can be used for focusing an ion beam linearly without aberrations* by the electric field of a confined electron cloud. They combine strong electrostatic focusing with the possibility of space charge compensation and provide an attractive alternative to conventional ion beam optics in a LEBT section. The focusing performance strongly depends on the density and distribution of the enclosed electron plasma*. As the Gabor lens is usually operated close to the ion source, residual gas ionization is supposed to be the central electron generation mechanism. An electron source is introduced in order to investigate the possibility of boosting the electron density in plasma traps using the example of a Gabor lens. This way, a Gabor lens could be operated under XUHV conditions, where residual gas ionization is suppressed. The particle in cell code bender** was used to simulate the injection into the confining fields of the space charge lens in different geometrical configurations and a prototype experiment was constructed consisting of a Gabor lens and an electron source system. In this contribution, simulations and measurements will be presented.
* Schulte, K., et al. Electron cloud dynamics in a Gabor space charge lens. 2012
** Noll, D., et al. The particle-in-cell code bender and its application to non-relativistic beam transport. 2015
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA005  
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THPVA006 Space-Charge Compensation in the Transition Area Between LEBT and RFQ 4425
SUSPSIK061   use link to see paper's listing under its alternate paper code  
 
  • P.P. Schneider, D. Born, V.A. Britten, M. Droba, O. Meusel, H. Podlech, A. Schempp
    IAP, Frankfurt am Main, Germany
  • D. Noll
    CERN, Geneva, Switzerland
 
  Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) #05P15RFRBA and by HORIZON 2020 for the MYRRHA project #662186
The transition from a space charge compensated beam in the LEBT to an uncompensated beam in the RFQ will influence the beam parameters. To investigate the impact of the electric fields on the space charge compensation, an insulated cone is used as a repeller electrode in front of the RFQ. Depending on the time dependent potential of the RFQ rods respectively to the beam potential, the compensation electrons may be prevented from moving into the RF field which oozes out of the RFQ entrance. The simulation studies are performed with the particle-in-cell code bender*. The simulations may substantiate measurements at the CW-operated RFQ in Frankfurt University** as well as at the foreseen MYRRHA LEBT-RFQ interface.*** In this contribution, a study on a LEBT-RFQ interface is shown. Results of numerical and experimental investigations will be compared.
*Noll, D. et al.The Particle-in-Cell Code Bender and Its Application to Non-Relativistic Beam Transport, WEO4LR02, HB'14
**Meusel, O. et al.FRANZ Accelerator Test Bench and Neutron Source.,MO3A03, LINAC'12
***R. Salemme et al.Design Progress of the MYRRHA Low Energy Beam Line, MOPP137, LINAC'14
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA006  
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