Thermoluminescence (TL) technique has been used to characterize and determine the dosimetric properties of natural sodium chloride (NaCl) salt extracted from the Seawater of the Mediterranean Sea. The TLD grade material was prepared by evaporation and annealing the powder obtained from the aqueous solution. The TL properties include the response to theb-irradiation dose and the effects resulting from annealing up to 700oC, heating rate and fading. The analysis involve using total Glow Curve Deconvolution (GCD) to separate the inherent overlapping TL-peaks and determine the TL characteristics and the trapping parameters using general order (GO)kinetics (activation energy, kinetic order, peak position of trap and the frequency factor). The GL-curves exhibit well defined TL-peaks around 140oC, 225oC and 380oC and response depending on the annealing temperature due to variations due to formation of the structural defects. A linear response was noticed over the delivered range of absorbed doses up to 4Gy. The fading results gave evidence that TL emission is due to a redistribution of trapping levels and indicate that the prominent TL-peak near 225oCis useful for TL-dosimetric applications. arabic 15 English 115
Fawzeia Khamis(5-2020)

Thermoluminescence (TL) of pure and Eu3+ and Dy3+ doped synthesis quartz was synthesized and their ion beam and thermoluminescence properties were investigated. The as prepared, doped and co-doped quartz and the effects of imparting 2 Gy beta dose and 2MeV 4He+ ion beam irradiation is investigated. The basic model proposed and can explain our observations is that, the dominant signals from the as prepared material arise from the incorporation of the transitions within the RE dopants enhanced by the intensity from the intrinsic or host defect sites within the synthesis quartz network. The complex shape TL glow curves indicate that irradiation causes major distortions to the lattice with the incorporation of extrinsic impurities and RE doping processes, induce perturbations and alter the energy levels pattern of the free ions and assigned transitions probabilities in a manner that that depends on the dopants, their concentrations and the host material. The larger Eu ions stabilize the emission more than that of the Dy ions. The TL peak temperatures are commonly correlated via charge transfer processes and scale with the ions size, in such a manner that the close proximity (or shallow traps) allows lower temperature electron release, whereas the more distant variants (deep traps) are less distorted, but are still able to couple to the higher energy orbitals of the Eu ions. arabic 26 English 120
Fawzeia Khamis(10-2020)

Thin films of pure ZnO have been prepared on glass substrate using the Sol–Gel spin coating technique. Transmittance and absorbance spectra have been measured by using double beam UV-Visible 1800 spectrophotometer in the wavelength range (300-800)nm. It was found that the absorbance decreases with increasing the wavelength, while the transmittance increases with rising the wavelength. The transmittance exceeds 90% in the visible light region and in the near-infrared. The obtained results have shown that intrinsic ZnO is a semiconductor of wide optical energy band gap estimated to be 3.33eV. Furthermore, some optical properties and optical constants have been calculated from absorption and transmission measurements such as absorption coefficient, Urbach energy, extinction coefficient, refractive index and dielectric constant. arabic 12 English 63
Fawzeia Khamis(8-2020)

Thin films of cobber doped ZnO have been prepared on glass substrate using the Sol-Gel spin coating technique. The effect of doping percentage of Cu to ZnO thin films on the optical properties and optical constants are concluded from absorption and transmission measurements which are obtained by using double beam UV-Visible 1800 spectrophotometer in the wavelength (300-800)nm. It was found that the transmittance increases with increasing the doping percentage (0.01, 0.02,0.03 and 0.04)mol%, while the Absorbance is decreased. The optical energy band gaps have been evaluated and their values seem to be decreased by increasing the doping concentration level in the range (0.01, 0.02, 0.03)mol% followed by a rise with increasing the doping level to 0.04mol%. arabic 17 English 84
Fawzeia Khamis(9-2020)

Dosimetry characterization and the evaluation of kinetics parameters of trapping states of Mg-doped ZnO phosphors synthesized by Sol-Gel technique. The thermoluminescence response of Mg-doped ZnO samples showed a linear response when exposed to X-ray radiation and the optimum annealing condition was 400oC/4h for the three concentrations. A broad-shaped TL glow curve with an upper bound of 270 °C, which shifts to lower temperatures with increasing dose, indicating that general order (GO) kinetics thermoluminescence processes are involved. We conclude that the ZnO doped Mg phosphors under study are promises to develop dosimeters for high radiation dose measurements. Kinetic parameters, such as activation energy (E), frequency factor (s), and order of kinematic order (b), were estimated by the Glow Curve Deconvolution (GCD) method. ZnO:Mg phosphor has a great potential as a dosimeter for monitoring in the fields of ionizing radiation. arabic 9 English 49
Fawzeia Khamis, , (1-2021)

Abstract The thermoluminescence (TL) response of pure and Eu-doped Dead Sea-(DS-) NaCl crystals was investigated after subjected to various beta excitation and irradiation at room temperature from 90Sr/90Y beta source with doses up to 4 Gy. The naturally occurring DS-NaCl samples result in broad glow curves characterized by high TL intensity and TL peak with maximum temperature observed around 200 °C and exhibiting a linear dose response between 0.25 and 1.25 Gy. In this respect, the crystals are considered useful to be passive radiation detectors for TL-dosimetry and applications. The TL measurements of the purposely added Eu and irradiated to 1 Gy crystals indicate a strong influence of the TL glow curves and result in a split of the single TL peak to two prominent peaks centered around 200–250 °C, with varying intensity in a manner that depends on the annealing temperature and in favor to the deeper trap peak. The intensity enhancement after doping with europium to the lattice is approximately sixfold in favor to the prominent TL peak detected near 200 °C. Phase purity and crystalline structure of the DS-natural and Eu-doped salts were analyzed by powder X-ray diffraction technique and comparison indicates good match with pure NaCl crystalline structure. arabic 9 English 66
Fawzeia Khamis(6-2021)