Author: Kester, O.K.
Paper Title Page
MOPAB19 Space-Charge Compensation of Intense Ion Beams by Nonneutral Plasma Columns 67
 
  • K. Schulte, M. Droba, O.K. Kester, S. Klaproth, O. Meusel, D. Noll, U. Ratzinger, K. Zerbe
    IAP, Frankfurt am Main, Germany
  • O.K. Kester
    GSI, Darmstadt, Germany
  
  Gabor lenses were con­ceived to focus a pass­ing ion beam using the elec­tri­cal field of a con­fined non­neu­tral plasma col­umn. Be­side its ap­pli­ca­tion as fo­cus­ing de­vice, in Gabor lenses space-charge ef­fects can be stud­ied in de­tail. The in­flu­ence of the elec­tron dis­tri­b­u­tion on emit­tance and space-charge dom­i­nated ion beams was in­ves­ti­gated in beam trans­port ex­per­i­ments*. In this con­tri­bu­tion we want to em­pha­size one re­sult of these ex­per­i­ments. The mea­sure­ments in­di­cated a strong con­tri­bu­tion of sec­ondary elec­trons on beam dy­nam­ics. Sec­ondary elec­trons are pro­duced within the trans­port chan­nel, par­tic­u­larly by in­ter­ac­tion of the beam with the sur­face of the slit-grid emit­tance scan­ner. This might lead to an in­crease of the fill­ing de­gree and to an im­proved fo­cus­ing per­for­mance of the lens. As­sum­ing that the loss and pro­duc­tion rates within the lens vol­ume and the trans­port chan­nel de­ter­mine the equi­lib­rium state of the non­neu­tral plasma col­umn, the elec­tron cloud was char­ac­ter­ized as a func­tion of the ex­ter­nal fields and the resid­ual gas pres­sure in small-scale table top ex­per­i­ments. In this con­tri­bu­tion ex­per­i­men­tal re­sults will be pre­sented in com­par­i­son with nu­mer­i­cal sim­u­la­tions.
* K. Schulte, “Studies on the focusing performance of a Gabor lens depending on nonneutral plasma properties”, PhD thesis, 2013. 		 
 
WEO3LR04 Emittance Transfer in Linacs 289
 
  • L. Groening, M.T. Maier, C. Xiao
    GSI, Darmstadt, Germany
  • O.K. Kester
    IAP, Frankfurt am Main, Germany
  
  Flat beams fea­ture un­equal emit­tances in the hor­i­zon­tal and ver­ti­cal phase space. Such beams were cre­ated suc­cess­fully in elec­tron ma­chines by ap­ply­ing ef­fec­tive stand-alone so­le­noid fringe fields in the elec­tron gun. This con­tri­bu­tion is an ex­ten­sion of the method to ion beams and on the de­cou­pling ca­pa­bil­i­ties of such a round-to-flat adap­tor. The beam line pro­vides a sin­gle-knob tool to par­ti­tion the hor­i­zon­tal and ver­ti­cal rms emit­tances, while keep­ing the prod­uct of the two emit­tances con­stant as well as the trans­verse rms Twiss pa­ra­me­ters (betax;y and alphax;y) in both planes. This sin­gle knob is the so­le­noid field strength. The suc­cess­ful com­mis­sion­ing of the set-up with beam will be pre­sented as well.  
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