Measurements of mass attenuation coefficient, effective atomic number and electron density of some amino acids

The mass attenuation coefficients of some amino acids, such as DL-aspartic acid-LR(C4H7NO4), L-glutamine (C4H10N2O3), creatine monohydrate LR(C4H9N3O2H2O), creatinine hydrochloride (C4H7N3O center dot HCl) L-asparagine monohydrate(C4H9N3O2H2O), L-methionine LR(C5H11NO2S), were measured at 122, 356, 511, 662, 1170, 1275 and 1330 keV photon energies using a well-collimated narrow beam good geometry setup. The gamma-rays were detected using NaI (Tl) scintillation detection system with a resolution of 0.101785 at 662 keV. The attenuation coefficient data were then used to obtain the effective atomic numbers (Z(eff)), and effective electron densities (N-eff) of amino acids. It was observed that the effective atomic number (Z(eff)) and effective electron densities (N-eff) initially decrease and tend to be almost constant as a function of gamma-ray energy. Z(eff) and N-eff experimental values showed good agreement with the theoretical values with less than 1% error for amino acids. Published by Elsevier Ltd.