Effective atomic number and electron density of amino acids within the energy range of 0.122–1.330 MeV

Autor: Rajkumar M. Lokhande, Chaitali V. More, Pravina P. Pawar
Rok vydání: 2016
Předmět:
Zdroj: Radiation Physics and Chemistry. 125:14-20
ISSN: 0969-806X
DOI: 10.1016/j.radphyschem.2016.02.024
Popis: Photon attenuation coefficient calculation methods have been widely used to accurately study the properties of amino acids such as n-acetyl- l -tryptophan, n-acetyl- l -tyrosine, d -tryptophan, n-acetyl- l -glutamic acid, d -phenylalanine, and d -threonine. In this study, mass attenuation coefficients ( µ m ) of these amino acids for 0.122-, 0.356-, 0.511-, 0.662-, 0.884-, 1.170, 1.275-, 1.330-MeV photons are determined using the radio-nuclides Co 57 , Ba 133 , Cs 137 , Na 22 , Mn 54 , and Co 60 . NaI (Tl) scintillation detection system was used to detect gamma rays with a resolution of 8.2% at 0.662 MeV. The calculated attenuation coefficient values were then used to determine total atomic cross sections ( σ t ), molar extinction coefficients ( e ), electronic cross sections ( σ e ), effective atomic numbers ( Z eff ), and effective electron densities ( N eff ) of the amino acids. Theoretical values were calculated based on the XCOM data. Theoretical and experimental values are found to be in a good agreement (error µ m , σ t , e , σ e , Z eff , and N eff with energy are shown graphically. The values of µ m , σ t , e , σ e are higher at lower energies, and they decrease sharply as energy increases; by contrast, Z eff and N eff were found to be almost constant.
Databáze: OpenAIRE
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