M.R. Kaçal

Studies on effective atomic numbers, electron densities from mass attenuation coefficients near the K edge in some samarium compounds

The effective atomic numbers and electron densities of some samarium compounds were determined using the experimental total mass attenuation coefficient values near the K edge in the X-ray energy range from 36.847 up to 57.142 keV. The measurements, in the region from 36.847 to 57.142 keV, were done in a transmission geometry utilizing the Kα2, Kα1, Kβ1 and Kβ2 X-rays from different secondary source targets excited by the 59.54 keV gamma-photons from an Am-241 annular source. This paper presents the first measurement of the effective atomic numbers and electron densities for some samarium compounds near the K edge. The results of the study showed that the measured values were in good agreement with the theoretically calculated ones.

Determination of K shell absorption jump factors and jump ratios of 3d transition metals by measuring K shell fluorescence parameters.

Energy dispersive X-ray fluorescence technique (EDXRF) has been employed for measuring K-shell absorption jump factors and jump ratios for Ti, Cr, Fe, Co, Ni and Cu elements. The jump factors and jump ratios for these elements were determined by measuring K shell fluorescence parameters such as the Kα X-ray production cross-sections, K shell fluorescence yields, Kβ-to-Kα X-rays intensity ratios, total atomic absorption cross sections and mass attenuation coefficients. The measurements were performed using a Cd-109 radioactive point source and an Si(Li) detector in direct excitation and transmission experimental geometry. The measured values for jump factors and jump ratios were compared with theoretically calculated and the ones available in the literature.

Chemical effect on the K shell absorption parameters of some selected cerium compounds

In this study, the photoelectric cross section values of Ce, CeCl3.7H2O, Ce2(SO4)3, Ce(OH)4 and Ce2O3 samples were measured in the energy range from 31.82 keV up to 51.70 keV by adopting in narrow beam geometry. Using these photoelectric cross sections, the K shell photoelectric cross sections at the K-edge, the K shell absorption jump ratios and jump factors, the Davisson-Kirchner ratios and K shell oscillator strength values were estimated experimentally. The measured parameters were compared with the theoretical calculated values. It is observed that the K shell photoelectric cross section at the K-edge and K shell oscillator strength values of an element are affected by the chemical environment of material while the K shell absorption jump ratio, K shell absorption jump factor and Davisson-Kirchner ratio are not affected by the chemical environment of material for the present samples. To the best of our knowledge, the chemical effects on the Davisson-Kirchner ratio and K shell oscillator strength have not been discussed for any element by now.

Calculation of absorption parameters for selected narcotic drugs in the energy range from 1 keV to 100 GeV

The total mass attenuation coefficients (μ/ρ), total molecular (σt,m), atomic (σt,a) and electronic (σt,e) cross sections, effective atomic numbers (Zeff) and electron density (NE) were computed in the wide energy region from 1 keV to 100 GeV for the selected narcotic drugs such as morphine, heroin, cocaine, ecstasy and cannabis. The changes of μ/ρ, σt,m, σt,a, σt,e, Zeff and NE with photon energy for total photon interaction shows the dominance of different interaction process in different energy regions. The variations of μ/ρ, σt,m, σt,a, σt,e, Zeff and NE depend on the atom number, photon energy and chemical composition of narcotic drugs. Also, these parameters change with number of elements, the range of atomic numbers in narcotic drugs and total molecular weight. These data can be useful in the field of forensic sciences and medical diagnostic.

Determination of Kα,β excitation factors in thin target for selected elements from Y to Te at 59.54 keV excitation energy

The paper presents the first measurements of the Kα and Kβ excitation factors for some selected elements from Y to Te. To determine the Kα and Kβ excitation factors, the experimental values of K shell X-ray production cross sections and total absorption photoelectric cross sections were used. The measurements were performed using a Si(Li) detector coupled with 2048 multichannel analyzer and an Am-241 annular radioisotope source which is emitted 59.54 keV γ-photons. It is observed that the Kα excitation factors are 5-6 times larger than the Kβ excitation factors. The measured excitation factors were compared only with theoretical calculated ones since there are no other experimental reports for the present elements in the literature. The present experimental values of Kα and Kβ excitation factors are in satisfactory agreement with the theoretical results.

Investigation of radiation shielding properties for some ceramics

Abstract In this work, the radiation shielding parameters like mass and linear attenuation coefficient, half value layer, tenth value layer, mean free path, effective atomic number, effective electron density, exposure buildup factor and fast neutron removal cross section were examined for the peridot, aluminum nitride, ruby, yttrium oxide, magnesium silicate, and silicon nitride ceramic samples. Furthermore, the dependence of the effective conductivity on the energy was investigated. The experimental studies were carried out in the photon energy range of 81 keV–1333 keV using a high resolution HPGe detector and six different radioactive sources. The experimental results were validated with the theoretical results and a good agreement was observed for all samples. The yttrium oxide has more shielding effectiveness for γ radiation, while magnesium silicate, aluminum nitride and silicon nitride possess least γ-ray shielding. However, the optimum neutron shielding material is ruby.

Updated database for K-shell fluorescence yields

This study presents a summary of experimental data of K-shell fluorescence yields (ωK) published in the period of time between 2010 to february-2017. The fluorescence yields (ωK) of elements in the range 23≤Z≤60 taken directly from different sources were reviewed and presented in a table form. Finally, the experimental and empirical values in the literature have been reported and commented.

Investigation of chemical effect on the absorption parameters for some selected indium complex at 59.54 keV photon energy

In this work, the mass attenuation coefficients, molecular, atomic and electronic cross sections, effective atomic numbers and electron densities of some selected indium complexes such as C5H10InNO9, C3H6InNO9 and C9H10InNO9, were determined with experimentally and theoretically using transmission geometry at 59.54 keV photon energy which emitted from 241Am annular source. The results were compared with the theoretical calculations which obtained from the WinXCOM program. Also, the results were interpreted based on some chemical parameters such as energy gap, ionization energy, electron affinity, hardness, chemical potential, electronegativity and global electrophilicity values of malonate, 2, 2 dimethylmalonate and phenylmalonate which were calculated using the density functional theory (DFT/B3LYP).