H+ and He2+ impact single and double ionization of lead Minakshi, L. K. Jha, S. N. Chatterjee and B. N. Roy Eur. Phys. J. D, 51 3 (2009) 331-339 Published online: 09 January 2009 DOI: 10.1140/epjd/e2008-00219-7