Browsing by All Authors "Durak, R."

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    Angular dependence of M x-ray production differential cross-sections at 5.96 keV
    (Azerbaijan National Academy of Sciences Institute of Radiation Problems ve Turkish Atomic Energy Authority, 2006) Durak, R.; Özdemir, Y.; Ateş, A.; Sağlam, M.; Erzeneoğlu, S.; Biber, M.; 2006; Bölüm Yok
    The knowledge of the angular dependence of M shell production differential cross-sections is important because of their extensive use in basic studies of photoelectric effect, characteristic X-ray production, internal conversion of γ-rays, radiative and non-radiative transition probabilities and development of more reliable angular dependence theoretical models describing fundamental inner-shell ionization processes. The angular dependence of M X-ray production differential cross-sections for selected heavy elements between Lu and Pt have been measured at 5.59 keV incident photon energy, at seven emission angles in the range 120° - 150° at intervals of 5°. The emission angle was set to 0°. The target M X-ray spectra were recorded by the collimated Si(Li) detector, which has an active area of 12.5 mm2, a sensitive crystal depth of 3 mm and a Be window of 0.025 mm thickness. The measured energy resolution of the detector system was 188 eV for an amplifier shaping time constant of 6 ps at the 5.9 keV peak of 55Fe. Angular dependence M X-ray production differential cross-sections have been derived, using the M-shell fluorescence yields, experimental total M X-ray production cross-sections and theoretical M-shell photoionization cross-sections. M X-ray production differential cross-sections are found to decrease with increase in the emission angle, showing an anisotropic spatial distribution of M X-rays. To the best of our knowledge, no other experimental results are available for worked elements in the angular range 120°-150° for comparison with present results. Extracted results have been compared with the theoretical predictions and semi empirical fits. The present experimental results are in good agreement with the theoretical values.
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    Effective atomic numbers of polypyrrole via transmission method in the energy range 15.74-40.93 keV
    (Azerbaijan National Academy of Sciences Institute of Radiation Problems ve Turkish Atomic Energy Authority, 2006) Erzeneoğlu, S.; İçelli, O.; Sağlam, M.; Durak, R.; Ateş, A.; Biber, M.; 46453; Bölüm Yok
    In the present work, effective atomic numbers (Zeff) of polypyrrole have been determined for total photon interactions at energy range 15.74 - 40.93 keV from the accurately measured total attenuation coefficients, by transmission method employing a good geometry setup for characteristic Ka and Kp X-rays of Zr, Mo, Ag, In, Sb, Ba and Pr. 59.54 keV gamma rays from 241 Am (100 mCi) source were used to excite the secondary targets. Characteristic X-rays of related elements after excited have been sent on polypyrrole using as target or absorber. Possible conclusions are compared with the theoretical ones obtained using the XCOM. The polypyrrole film has been directly formed on an aluminum plate by means of an anodization process. A Pt plate was used as the cathode. Anodization process was carried out under constant current conditions of I = 1mA. The polypyrrole/Al/polypyrrole structure was fabricated by an electrolyte being held at a constant temperature of 55 °C that was composed of 0.40 M pyrrole and 0.1 M tetrabutylammoniume tetrafluoroborate. The electrolyte solution was prepared in a propylene carbonate solvent (Merck). The polypyrrole has been coated on each side of aluminum plate. The area and thickness of the A1 plate are 1 cm2 and 0.012 cm, respectively.
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    Experimental studies on the coherent scattering of 59.5 keV γ-rays
    (Azerbaijan National Academy of Sciences Institute of Radiation Problems ve Turkish Atomic Energy Authority, 2006) Erzeneoğlu, S.; Sağlam, M.; Biber, M.; Ateş, A.; Durak, R.; O. İçelli; 46453; Bölüm Yok
    In this study, we have measured differential cross sections for coherent scattering by experimentally. A high- purity germanium detector was used to determine differential cross sections for coherent scattering of 59.5 keV γ-rays. The experiment was performed using a filtered point source of Am-241 of intensity 100 mCi. To obtain the net pulse height spectra of scattered γ-rays, a background spectrum without the scatterer was stripped from the spectrum acquired for the same time and experimental conditions. The experimental differential cross sections were compared with theoretical values calculated from predictions of nonrelativistic (NRFF), relativistic (RFF) and relativistic modified (RMFF) form factor theories.
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    X-ray irradiation effects on the interface of polypyrrole/p-Si structure
    (Azerbaijan National Academy of Sciences Institute of Radiation Problems ve Turkish Atomic Energy Authority, 2006) Biber, M.; Sağlam, M.; Erzeneoğlu, S.; Ateş, A.; Durak, R.; Türüt, A.; Bölüm Yok
    The samples were prepared using mirror cleaned and polished (as received from the manufacturer) p-type Si wafers with (100) orientation and 15-20 Q cm resistivity and 300-400 pm thickness. The ohmic contact was made by evaporating A1 on the back of the substrate, followed by a temperature treatment at 600 °C for 3 min in a N2 atmosphere. The native oxide on the front surface of p-Si was removed in a HF:H20 (1:15) soluüon and finally the wafer was rinsed in deionized water before polymerization was carried out. The ohmic contact made and the edges of the p-Si substrate used as an anode were carefully covered by wax so that the polished and cleaned front side of the sample was exposed to the electrolyte by mounüng it in an experimental set-up employed for anodizaüon. A Pt plate was used as the cathode. Anodization process was carried out under constant current conditions of I = 1mA. The polypyrrole/p-Si diode was fabricated by an electrolyte being held at a constant temperature of 55 °C that was composed of 0.40 M pyrrole and 0.1 M tetrabutylammonium tetrafluoroborate. The electrolyte solution was prepared in a propylene carbonate solvent (Merck). The Polypyrrole/p-Si/Al structure has demonstrated rectifying behavior by the current-voltage cuives studied at room temperature. The sample was exposed to x-ray irradiation up to 50 keV at constant doses in order to determine effect of x-ray radiation on interface between polypyrrole and Si semiconductor. The parameters of the structure such as barrier height, ideality factor, series resistance and interface state density are determined how to change with the irradiation. The interface state density distribution curves of device was obtained from forward bias current-voltage (I-V) characteristic.