The total attenuation coefficients,σtot, of biological materials such as amino acids have been studied as a function of weight fraction of constituent elements (hydrogen, carbon, oxygen and nitrogen).It is observed that in low energy region, the total attenuation coefficients,σtot is having higher value and as energy increases σtot values goes on decreasing. Also initially as weight fraction increases σtot values increase and then remain constant. The results have been presented in graphical form.
