Akademik Veri Yönetim Sistemi
9 th INTERNATIONAL HALICH CONGRESS ON MULTIDISCIPLINARY SCIENTIFIC RESEARCH, İstanbul, Türkiye, 3 - 04 Aralık 2025, ss.183, (Özet Bildiri)
The gamma spectrometric method is used to determine the natural and artificial radioactivity levels of various materials, including environmental, food, and construction materials. In radioactivity calculations, several corrections must be applied. Self-attenuation correction is a crucial factor that compensates for the reduction in photopeak count rate caused by gamma-ray absorption within the sample, which depends on the matrix composition and density. This effect becomes especially significant at low photon energies (<200 keV) and in samples with highdensity matrices. In this study, self-attenuation correction factors for twelve cement samples were determined over a gamma-ray energy range of 59.5 keV (²⁴¹Am) to 1408 keV (¹⁵²Eu) using two approaches: (1) theoretical estimation based on calculated mass attenuation coefficients, and (2) empirical determination through direct measurement. Gamma-ray spectra were acquired using a p-type coaxial high-purity germanium (HPGe) detector with a relative efficiency of 40% and an energy resolution of 1.8 keV at 1332 keV for ⁶⁰Co. The detector was coupled to a digital spectrometer, and MAESTRO software was used for photopeak analysis. In the first approach, the mass attenuation coefficients at the selected energies were calculated using the EPIXS database, and self-attenuation correction factors were derived according to the Beer–Lambert law. In the second approach, empirical correction factors were obtained using the gamma transmission method with ²⁴¹Am, ⁵⁷Co, ¹³⁷Cs, ¹⁵²Eu, ⁵⁴Mn, and ⁶⁵Zn point sources. The self-attenuation correction factors of the samples showed strong agreement between the empirical and calculated methods, ranging from 1.01 to 1.41 and 1.05 to 1.32, respectively. The highest correction values were observed at an energy of 59.5 keV for ²⁴¹Am, where selfattenuation effects are most pronounced due to enhanced photon absorption at lower energies. Neglecting these correction factors in radioactivity calculations can lead to errors of up to 30– 40%, particularly for low-energy gamma rays. Overall, the results confirm that both theoretical and empirical methods provide reliable estimations of self-attenuation effects, supporting their application in radioactivity calculations using gamma spectrometry