An axisymmetric system to recover beam energy from partially neutralized H- beams was recently proposed, for a given beam acceleration voltage Vs. In the case of ion source NIO1 Vs may range from 20 to 60 kV. A realistic beam with 3 mrad divergence, and a composition of 25 : 50 : 25 of H-, H0and H+has been considered. The collector works by decelerating the H- ions (into a system similar to a Faraday cup provided with an exit hole electrode), so that they are radially deflected by space charge and anode lens effects, and collected to a low kinetic energy Kc(less than 1 keV), while neutral and H+ions can pass through the exit hole electrode. A following collector can recover H+energy. Since the space charge calculations are challenging for highly nonlinear problem and for a possible (numerically unstable) virtual cathode phenomena different computation tools were compared for simulations. Stabilization techniques are compared. Limits for local perveance are discussed. Also mesh asymmetry effects and the related transverse oscillations of H+beam may be observed. Efficiency over 90 % can be reached in typical conditions. The secondary yield (which is low thanks to low impact energy Kcand Faraday cup concept) is estimated.
|Publication status||Published - 9 Aug 2017|
|Event||5th International Symposium on Negative Ions, Beams and Sources, NIBS 2016 - Oxford, United Kingdom|
Duration: 9 Aug 2017 → …
|Conference||5th International Symposium on Negative Ions, Beams and Sources, NIBS 2016|
|Period||9/8/17 → …|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)