Low energy beam transport for HIDIF

Low energy beam transport (LEBT) for a heavy ion inertial fusion (HIDIF, I. Hofmann and G. Plass, Report of the European Study Group on Heavy Ion Driv en Inertial Fusion for the Period 1995-1998) facility suffers from high spa ce charge forces and high ion mass. Space charge compensation reduces the n ecessary focusing force of the lenses and the radius of the beam in the LEB T, and therefrom the emittance growth due to aberrations and self fields is reduced. Gabor lenses (D. Gabor, Nature 160 (1947)) providing a stable spa ce charge cloud for focusing and combine strong cylinder symmetric focusing with partly space charge compensation and low emittance growth. A high tol erance against source noise and current fluctuations and reduced investment costs could be other possible advantages. The proof of principle has alrea dy been demonstrated (J.A. Palkovic, Measurements on a Gabor lens for Neutr alizing and Focusing a 30 keV Proton beam, University of Wisconsin, Madison , 1989; J. Pozimski, P. Gross, R. Dolling and T. Weis, First experimental s tudies of a Gabor plasma-lens in Frankfurt, Proceedings of the 3rd EPAC Con ference, Berlin, 1992). To broaden the experiences and to investigate the r ealisation of a LEBT concept for the HIDIF injector an experimental program using two Gabor lenses for independent variation of beam radius and envelo pe angel at RFQ injection was started. Therefrom the first experimental res ults using a double Gabor lens (DGPL) LEBT system for transporting an high perveance Xe+ beam are presented and the results of numerical simulations a re shown. (C) 2001 Elsevier Science B.V. All rights reserved.