Demet Yılmaz

Determination of the saturation thickness and albedo factors for mercury(II) oxide and lead(II) oxide

ABSTRACT It is important to know the saturation thickness and reflecting power of a target for accurate x-ray analysis. In the present work, the saturation thickness was determined by using photons scattered from mercury(II) oxide and lead(II) oxide targets. Also, albedo factors (albedo number, albedo energy and albedo dose) were determined experimentally. Mercury(II) oxide and lead(II) oxide were excited by 59.54 keV gamma rays emitted from a 241Am annular radioactive source with 5 Ci activity by energy dispersive x-ray fluorescence. The scattered and emitted x-rays were counted by a high-purity germanium detector with a resolution of 182 eV at 5.9 keV at a scattering angle of 168o. The saturation thickness decreased with the increasing mean atomic number. The albedo factors decreased with increasing target thickness.

Measurement of mass attenuation coefficients for undoped and boron nitride–doped magnesium diboride superconductors in the x-ray region 8.04–59.5 keV

ABSTRACT In this study, mass attenuation coefficients of the undoped and 2% boron nitride–doped magnesium diboride superconductor samples were investigated. Mass attenuation coefficients were measured at 8.04–59.5 keV x-ray energies by using a high-purity germanium detector with a resolution of 182 eV at 5.9 keV. It is observed that mass attenuation coefficients in undoped and doped magnesium diboride samples decrease with increasing photon energy, and doping with the boron nitride leads to increase the absorption of the electromagnetic radiation.

Albedo factors of some elements in the atomic number range 26≤Z≤79 for 59.54 keV

In this study, we aimed to determine the albedo factors for Fe, Co, Ni, Cu, Zr, Mo, Ag, Dy, Yb, and Au. Albedo factors were investigated experimentally for 59.54keV photon energy by using an HPGe detector with a resolution of 182eV at 5.9keV. Albedo number (AN), albedo energy (AE), and albedo dose (AD) were plotted as a function of atomic number of the target. It was observed that albedo factors decreased with increasing atomic number. In addition, there was a good third-order polynomial relationship between the albedo factors and atomic number.

Characterization of the effective atomic number for first row transition elements by the ratio of coherent to compton scattering intensities obtained by wavelength dispersive X-ray fluorescence

ABSTRACT The effective atomic numbers of compounds of the first row transition elements were determined experimentally by a scattering method using wavelength dispersive X-ray fluorescence spectrometer. A calibration curve was created by using the intensity ratios of coherent to Compton scattered peaks of pure elements from atomic number 13–48. This relationship was employed to determine the effective atomic numbers of the compounds. The effective atomic numbers were also calculated by using empirical formulas from the literature. Mass attenuation coefficients were calculated using software. The experimentally measured values of the effective atomic numbers with the calculated values by empirical formulas were comparable.

X- and gamma-ray irradiation effects on vanadium pentoxide thin films

Abstract Thickness and composition of thin films can be measured with X- and gamma-rays. In this work, thickness and composition of vanadium pentoxide thin films are investigated by energy dispersive and wavelength dispersive X-ray fluorescence systems. Also, the surface analysis of vanadium pentoxide thin films irradiated with Rhodium Kα X-rays and 59.54 keV gamma-rays emitted from 100 mCi and 5 Ci Americium-241 radioactive sources is performed by scanning electron microscope. It is observed that X- and gamma-rays are destructive for vanadium pentoxide thin films. Also, the composition of vanadium pentoxide thin films changes by irradiation with X- and gamma-rays.

Energy absorption buildup factors of some potential bioactive compounds in the energy region 0.015–15 MeV

ABSTRACT Kinetic energy released per unit mass relative to air and energy absorption buildup factors has been calculated for some potential bioactive compounds in the energy region of 0.015–15 MeV. The bioactive compounds of 1-aryl-3-dibenzylamino-propane-1-on hydrochloride type Mannich bases were used in this work. Aryl part was changed as C6H5 (1), 4-CH3C6H4 (2), C4H3S-2-yl (3), 4-FC6H4 (4), 4-BrC6H4 (5), 4-ClC6H4 (6), and 4-NO2C6H4 (7). The energy absorption buildup factors have been calculated for penetration depth of 40 mean free paths. It is observed that kinetic energy released per unit mass relative to air depends on the photon energy and chemical content of compounds. The compounds with least mean atomic number possess the maximum value of energy absorption buildup factors. Also, the energy absorption buildup factors are found the highest in intermediate energy, whereas the lowest in low as well as high energies.

Buildup factors and kerma for Al2O3 and SiO2 in the energy range 0.015-15 MeV

The energy absorption buildup factors (EABF) have been calculated for some thermoluminescent dosimetric materials (Al2O3 and SiO2) in the energy region 0.015-15 MeV up to the penetration depth of 40 mean free paths (mfp). Also, kerma relative to air has been determined for these materials. It is observed that the energy absorption buildup factors and kerma relative to air depend on the photon energy and chemical content. Also, the energy absorption build up factors are found the highest in intermediate energy whereas the lowest in low- as well as high energies.

L-shell differential cross-section and alignment of uranium at 59.54-keV photon energy

L X-ray differential cross-sections of uranium were calculated at several polar scattering angles (85°, 95°, 105°, 115°, 125°, and 135°) at 59.54-keV photon energy by using a Si(Li) detector. We observed that Ll and Lα X-rays were dependent on the polar scattering angle, whereas Lβ and Lγ X-rays were independent of the polar scattering angle. Therefore, the anisotropy parameters for Ll and Lα X-rays were obtained using the intensity ratios of Ll to Lγ X-rays and of Lα to Lγ X-rays to reduce some systematic errors.