Multiple Electron Stripping of 3.4MeV/µ Kr7+ and Xe11+ in Nitrogen
Authors: D. Mueller, L. Grisham, I. Kaganovich, R.L. Watson, V. Horvat, K.E. Zaharakis, and M.S. Armel
Date of PPPL Report: December 2000
Published in: Phys. Plasmas 8 (May 2001) 1753-1756. (Note: title changed to Multiple Electron Stripping of 3.4 MeV/amu Kr7+ and Xe11+ in Nitrogen.)
Use of heavy ions beams with ~10 MeV/µ , mass ~ 200 and average charge state of 1+ has been proposed as a driver for heavy ion fusion. Stripping of the ion beam by background gas results in an increase in the space charge density of the beam, which may make focusing the intense ion beam onto small targets more complex. Knowledge of the electron-loss-cross-sections is essential to understand and address the problem. Currently, there are no 10 MeV/µ , mass = 200, charge state = 1 beams available, and the theories that calculate electron-loss-cross-sections can be experimentally tested only by using available beams of somewhat lower energy and higher initial charge state. The charge state distribution of ions produced in single collisions of 3.4 MeV/µ Kr7+ and 3.4MeV/µ Xe11+ in N2 have been measured at the Texas A&M Cyclotron Institute using a windowless gas cell. The charge states of the outgoing ions are determined by magnetic analysis using a position-sensitive microchannel-plate detector. The cross-sections for single and multiple electron loss are determined, and the results indicate that substantial multiple-electron loss occurs. The relative cross-section for loss of i +1 electrons is 0.3 to 0.7 times that for i electron loss. The average number of electrons removed per one collision (sum of the electron-weighted cross-sections normalized to the total cross-section) is 1.86 for Kr and 1.97 for Xe.