Ion beam irradiation induces important biological effects and it is a long-standingtask to acquire both qualitative and quantitative assessment of these effects. One effective wayin the investigation is to utilize Fourier transformation infrared (FTIR) spectroscopy becauseit can offer sensitive and non-invasive measurements. In this paper a novel protocol was employedto prepare biomolecular samples in the form of thin and transversely uniform solid filmsthat were suitable for both infrared and low-energy ion beam irradiation experiments. Underthe irradiation of N^+ and Ar^+ ion beams of 25 keV with fluenee ranging from 5×10^(15) ions/cm^2to 2.5×10^(16) ions/cm^2, the ion radio-sensitivity of four amino acids, namely, glycine, tyrosine,methionine and phenylalanine, were evaluated and compared. The ion beam irradiation causedbiomolecular decomposition accompanied by molecular desorption of volatile species and the damagewas dependent on ion type, fluence, energy and types of amino acids. The effectiveness ofapplication of FTIR spectroscopy to the quantitative assessment of biomolecular damage doseeffect induced by low-energy ion radiation was thus demonstrated.
