α-Glycine radiolysis induced by keV He+ beam

Murchison meteorite analysis revealed the presence of 17 primary amino-acids and 13 sugars. Major questions are how prebiotic materials were formed and how they could survive billions of years in the interplanetary medium. Considering keV energy α particles abundant in the Solar System, this work aims to determine in laboratory glycine radioresistance at those conditions. Glycine films were irradiated by 0.5, 1.0, 1.5 and 2.0 keV He + ions. Experimental data show glycine destruction-cross-section ( σ d ) dependence as the temperature increases, from 0.06 x 10 -16 cm 2 at 10 K to 1.2 x 10 -16 cm 2 at 300 K. At high irradiation energies glycine degradation is faster, varying σ d from 0.16 x 10 -16 cm 2 at 0.5 keV to 3.35 x 10 -16 cm 2 at 2 keV. TRIM extended model was developed for comparison with experimental data, qualitative agreement and numerically results are good for low energies (0.5 and 1.0 keV) and reasonable for higher energies (2.0 keV).