[en] An optical method is presented for alpha spectroscopy by measuring the optical density of etched CR-39 samples irradiated with different alpha particle energies. The relation between the optical density per track, alpha energy and etching conditions were studied using a simple experimental setup. An empirical formula to calculate the stopping power of alpha particles in a CR-39 detector is proposed in this study

[en] A technique based on the optical density (D) measurement of the etched track is useful for charged particles spectroscopy using SSNTD. It was shown that the stopping power of alpha particles in CR-39 is proportional to D. We measured the optical density and derived an expression to estimate the range of alpha particles in CR-39 detector as a function of the bulk etching rate and etching time. The relation between the etching time, track parameters (depth, radius) and D for different alpha particles energy and etching conditions were studied. A relation describing D as a function of track size is proposed

[en] Lithium haloborate glasses in the form (70-y)B₂O₃-30BaF₂-yLiX, where y=0, 5, 10, 15 and 20 mol% and X=F, Cl and Br were prepared. Using the differential thermal analysis technique the glass transition temperature T_g was determined and discussed in view of the glass structure. Experimental and theoretical investigation of the dc conductivity of the glasses was carried out. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

[en] Nano Co_3O_4 has been fabricated by co-precipitation of 0.1 M cobalt chloride with 0.1 M oxalic acid. During precipitation, high-frequency signal (9 V) was applied to the precipitation bath. Three samples were prepared at three different frequencies (0 Hz, 400 KHz, 1 MHz). The samples were dried at 120 °C for 20 h, and then calcined at 700 °C for 5 h to obtain the nano Co_3O_4. The prepared samples were investigated via XRD and TEM studies. According to the present data the particle size decreases from about 164 to 80 nm and the width of the particle size distribution decreases to half of its value with increasing frequency from 0 Hz to 1 MHz. (paper)

[en] Exposure of Makrofol DE 1-1 nuclear track detectors to high gamma ray doses causes a great effect on their structural and etching properties, as well as on the recorded track parameters. Samples of Makrofol DE 1-1 SSNTDs were irradiated with gamma doses in the range of 1-100 kGy using 1.25 MeV ⁶⁰Co source of dose rate 4 kGy/h. Etching and optical characterization of these detectors have been respectively studied through the measurements of bulk-etch rate, V_B, and UV-visible absorption spectra of blank and γ- irradiated samples. Results reveal that V_B shows an increase with increasing γ-dose, while the etching activation energy, E_B, shows a decrease. The UV-visible spectra of γ- irradiated samples revealed color centers in the range (310-320 nm). The optical band gap energies (direct and indirect) were found to decrease with increasing γ- dose. Values of direct band gap energies (4.33-4.12 eV) have been found to be higher than those extracted from indirect approach (4.12-3.82 eV) at the same gamma-dose. Results of the present work have been explained on the basis of γ-interaction mechanisms with the polymeric detectors, and the formation of bond breakage, chain scission, free radicals etc. The use of Makrofol DE 1-1 in gamma dose determination is also discussed. (author).

[en] The d.c. resistivity (rho) of 15 Na₂O, 20 CaO, 65 SiO₂, xTiO₂ (mole %) glasses was investigated in the temperature range 353-523 K. The conduction mechanism was mainly ionic with Na⁺ as a charge carrier. The changes in resistivity as x increased are attributed to different structural contributions of Ti at various contents. The effect of gamma irradiation (up to dose value D 76.5 Mr) on the conduction mechanism of the prepared glasses was also studied. An empirical model was adopted to fit the experimental plots of the glass resistivity as a function of x and D in the range 12.8 < = 1n D < 18.1. It is revealed that this glass system can be used as an electronic dosimeter. (author)

[en] Superconductor samples of YBa_2Cu_3O_7_−_δ (YBCO) + x where x = 0.1, 0.2, 0.3, 0.4 and 0.5 wt% of nano metal oxides namely Cr_2O_3, Co_3O_4 and Mn_3O_4 namely are synthesized by the solid-state reaction route. Both x-ray diffraction and electron microscopy have been employed to study the phase identification and the microstructure of these samples. Transition temperature of the samples has been determined by four probe resistivity measurements. The x-ray diffraction patterns indicate that the gross structure of YBCO does not change with the substitution of three types of nano metal oxides with different doping level. The critical transition temperature (T_c) is found to decrease with the increases of doping level. Mn_3O_4 has highest T_c value which may be due to flux pinning from some defects and the rapid suppression in T_c with increasing concentration of Mn_3O_4 may be due to the cooper pair breaking and the hole filling in the CuO_2 planes. (paper)

[en] Bulk superconductor samples of YBa₂Cu₃O_7−δ (YBCO) doped with nano metal oxides of Mn₃O₄, Co₃O₄, Cr₂O₃, CuO and SnO₂ respectively with 0.2 wt% are synthesized by a solid-state reaction route. The structural characterization of all samples has been carried out by x-ray diffraction (XRD) and scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The XRD patterns indicate that the magnetic doping of nano metal oxides $({\mathrm{M}\mathrm{n}}_3{\mathrm{O}}_4,{\mathrm{C}\mathrm{o}}_3{\mathrm{O}}_4,{\mathrm{C}\mathrm{r}}_2{\mathrm{O}}_3)$ gives a high value of orthorhombicity of the YBCO samples which is the result of high oxygen content, and consequently could give better superconducting properties contrary to the non magnetic nano oxides (CuO, SnO₂). The critical temperature (T_c) of the studied samples was found to improve by nano magnetic doping and lower with nano nonmagnetic doping. The superconducting transition temperature Tc determined from electrical resistivity measurements was found to increase for Mn₃O₄ (5.27 μB) doping and decrease for other metal oxides doping. (paper)