| Paper | Title | Page |
|---|---|---|
| MOPAB039 | Development of a Control System Based on Experimental Data for Space Charge Lenses | 166 |
|
||
|
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 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPVA059 | Overcoming the Space Charge Limit: Development of an Electron Lens for SIS18 | 2211 |
|
||
| The 'Facility for Anti-Proton and Ion Research' (FAIR) presently under construction will deliver intense ion beams to its experimental users. The requested intensities require filling the existing synchrotron SIS18, which serves as injector to FAIR, up to the space charge (SC) limit. Operation under these conditions is challenging due to the large tune footprint of the beam, demanding delicate control of adverse effects caused by machine imperfections to avoid emittance growth and beam loss. To facilitate the high intensity operation, the installation of an electron lens for SC compensation into SIS18 is foreseen. This requires an electron beam of a current of several amperes with longitudinal and transverse distributions matched to those of the ion beam during the cycle. The electron beam needs to be RF modulated at a bandwidth of a few MHz with time varying amplitude ranging from DC to fully modulated, while the transverse size needs to be continuously adapted to the adiabatically shrinking ion beam. This contribution reports on the requirements on an electron lens for SC compensation in SIS18. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA059 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| THPVA005 | Investigation of Electron Beam Assisted Density Boosting in Plasma Traps Using the Example of a Gabor Plasma Lens | 4421 |
|
||
|
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 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |