Signatures of laser photon energy in (e, 2e) reactions in helium Abdelkader Makhoute, Imane Ajana, Driss Khalil, Abdelmalek Taoutioui and Alain Dubois Eur. Phys. J. D, 70 11 (2016) 249 Published online: 22 November 2016 DOI: 10.1140/epjd/e2016-70161-2