Comment on "Observation of neutronless fusion reactions in picosecond laser plasmas".

The paper by Belyaev [Phys. Rev. E 72, 026406 (2005)] reported the first experimental observation of alpha particles produced in the thermonuclear reaction 11B(p,alpha)8Be induced by laser irradiation on a 11B polyethylene (CH2) composite target. The laser used in the experiment is characterized by a picosecond pulse duration and a peak of intensity of 2x10(18) W/cm(2). We suggest that both the background-reduction method adopted in their detection system and the choice of the detection energy region of the reaction products are possibly inadequate. Consequently the total yield reported underestimates the true yield. Based on their observation, we give an estimation of the total yield to be higher than their conclusion, i.e., of the order of 10(5)alpha per shot.