Examining alloying effect on K X ray intensity ratios and chemical shifts of the Zn, Mn and mixed spinel ferrites.

K X-ray emission spectra of Zn, Mn and mixed (Zn-Mn, Zn- Co, Zn-Ni) spinel ferrites have been acquired by inducing 59.54 keV and 22.1 keV γ-rays emitted from 3 Ci 241Am annular source and 40 mCi 109Cd point source with a HPGe detector. Some vital parameters for XRF, Kß/Kα X-ray intensity ratios, the full width at half maximum (FWHM) values, asymmetry index (As), peak energies and chemical shifts (ΔE), were defined depending on the alloying effect by working on the spectra. The obtained results exhibited that, compared to the pure states of the metals, chemical shifts aroused due to different crystal structure, valence electron structure, bond type and length in the spectrum of the alloy form. The difference of the electronegativity of the metals forming the ferrite obviously explained the change in the Kß/Kα X-ray intensity ratios. It has been concluded that the charge transfer mechanism predominates mainly and altered the intensity ratios of the metal by affecting the rearrangement of the 3d electrons in the valence band.

Effect of external magnetic field on the Kß/Kα X-ray intensity ratios of TixNi1-x alloys excited by 59.54 and 22.69keV photons.

The effects of external magnetic field and exciting photon energies on the Kß/Kα X-ray intensity ratios of various alloy compositions of Ti-Ni transition metal alloys have been investigated in this work using X-ray fluorescence spectroscopy. The spectrum of characteristic K-X-ray photons from pure Ti, pure Ni and TixNi1-x (x=0.30; 0.40; 0.50; 0.60; 0.70) alloys were detected with a high resolution Si (Li) solid-state detector. Firstly, Kß/Kα X-ray intensity ratios of pure Ti, pure Ni and TixNi1-x alloys were measured following excitation by 59.54keV γ-rays from a 200mCi (241)Am radioactive point source without any magnetic field and under 0.5 and 1T external magnetic fields, separately. Later, the same measurements were repeated under the same experimental conditions for 22.69keV X-rays from a 370 MBq(1)(0)(9)Cd radioactive point source. The results obtained for Kß/Kα X-ray intensity ratios of pure Ti, pure Ni, Ti and Ni in various Ti-Ni alloys were evaluated in terms of both external magnetic field effect and exciting photon energy effect. When the results obtained for both exciting photon energies are evaluated in terms of changing of Kß/Kα X-ray intensity ratios depending on the alloy composition, the tendency of these changes are observed to be similar. Also, Kß/Kα X-ray intensity ratios for all samples examined have changed with increasing external magnetic field. Therefore, the results obtained have shown that Kß/Kα X-ray intensity ratios of Ti and Ni in TixNi1-x alloys are connected with the external magnetic field. The present study makes it possible to perform reliable interpretation of experimental Kß/Kα X-ray intensity ratios for Ti, Ni and TixNi1-x alloys and can also provide quantitative information about the changes of the Kß/Kα X-ray intensity ratios of these metals with alloy composition.

Determination of energy absorption and exposure buildup factors by using G-P fitting approximation for radioprotective agents.

PURPOSE: Recently, there has been an increase in interest into research into radioprotective agents. Radioprotectors are compounds that protect against radiation injury when given orally (through drinking water) prior to radiation exposure. The purpose is to achieve preferred protection of normal tissues against injury inflicted by ionizing radiation used to treat tumors. The main aim of this work is to investigate energy absorption (EABF) and exposure buildup factors (EBF) of commonly used some radioprotective agents. MATERIALS AND METHODS: We have used the Geometric Progression (G-P) fitting method for calculating the equivalent atomic number (Zeq), for EABF and EBF buildup factors of the radioprotective agents in the energy range 0.015-15 MeV for penetration depths up to 40 mean free path. RESULTS: Significant variations in both EABF and EBF values were observed for several agents at the moderate energy region. At energies below 0.1 MeV, EABF and EBF values increased with decreasing equivalent atomic number Zeq of the samples. At energies >0.15 MeV, EABF and EBF values were found to decrease with decreasing Zeq of all agents. In addition, EABF and EBF were the largest for carnosin, tempol, melatonin, interferon gamma and orientine at 0.05 and 0.06 MeV, respectively, and the minimum values of buildup factors were at 0.1 MeV for cysteine, amifostine, penicillamine and glutathione. CONCLUSIONS: Cysteine and amifostine are good compounds for gamma rays absorption applications among the selected compounds. The presented results in this study are expected to be helpful in radiation dosimetry.