Ferdi Akman

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.

Determination of L X-ray fluorescence parameters for Ho, Lu, W, Hg and Bi.

In this work, L X-ray fluorescence cross sections, L sub-shell fluorescence yields and level widths and radiative vacancy transfer probabilities of L sub-shells to Mi, Ni and Oi sub-shells were measured for the elements Ho, Lu, W, Hg and Bi. Energy dispersive X-ray fluorescence (EDXRF) technique was used to measure L X-ray photons. To obtain related parameters, we used 59.54 keV gamma photons of (241)Am radioactive point source. Emitted L X-ray photons from targets were collected by means of a Si(Li) detector with resolution of 180 eV at 5.9 keV. The present results are generally in a good agreement with theoretical calculations and the other results obtained in the literature, within their range considering experimental uncertainty.

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.

Experimental values of K to Li sub-shell, K to L, and K to M shell vacancy transfer probabilities for some rare earth elements.

The K to Li (i=2,3), K to L, and K to M shell vacancy transfer probabilities for La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Er were determined at 59.54keV using a reflection geometry. The measurements were performed using an (241)Am annular radioactive source and a high resolution Si(Li) detector. The experimental results were compared with the theoretical values of Hartree-Slater and Hartree-Fock theories, semi-empirical and other available experimental results in the literature. Reasonable agreement is observed between the measured and theoretical results.

Evaluation of radiation absorption capacity of some soil samples

Abstract The aim of the present work is to investigate the radiation absorption capacity of different soil samples in Turkey. For this purpose, we used a γ ray transmission geometry to measure the mass attenuation coefficients of eight soil samples collected between Bingöl city and Solhan district, Turkey at different γ-ray energies in the range of 13.94–88.04 keV. The radioactive sources utilized in the experiment were 241Am, 109Cd and 133Ba. FFAST and WinXCOM programs were used to evaluate the theoretical mass attenuation coefficients values of the selected soil samples. There is a good agreement between experimental and theoretical results. Additionally, the mass attenuation coefficients values used to evaluate different radiation shielding parameters such as effective atomic number, half value layer and mean free path. The variation of shielding parameters was examined for soil composition and photon energy. The obtained results revealed that S6 soil sample is the best soil in terms of shielding effectiveness among all the collected soils due to lower values for half value layer and mean free path. The effective removal cross-section (ΣR) of fast neutrons for the collected soils was also computed to examine neutrons shielding properties of the soil samples. It is found that the ΣR values for the soil samples are almost constant and lie within the range (0.04286–0.04949 cm−1).

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.

Photon-Induced L-Shell X-Ray Production Cross Sections for Lanthanides at 59.54 keV

The Ll, Lα and Lβ X-ray production cross sections for Pr, Nd, Sm, Eu, Gd and Tb elements were determined using a reflection geometry. The excitation was performed with a 241Am radioactive annular source and the L X-rays emitted from targets were counted with a high-resolution Si (Li) detector. The experimental values were compared with other available experimental results and theoretical data. An agreement is observed between the measured and other experimental results or theoretical data.