Second-order Born calculation of laser-assisted single ionization of helium by electrons Abdelkader Makhoute, Imane Ajana, Driss Khalil and Souhaila Chaddou Eur. Phys. J. D, 69 6 (2015) 160 Published online: 18 June 2015 DOI: 10.1140/epjd/e2015-60141-5