[en] Synthesis of CdTe at the rate CdS core at the rate shell quantum dots using gamma irradiation method is reported through this paper. Quantum dots (QDs), synthesized using hydrothermal techniques, were exposed to gamma radiation from 300 Gy to 20 kGy. These QDs were characterized to confirm the growth of CdTe at the rate CdS core at the rate shell structure of QD using Photo luminescence (PL) spectroscopy and X-ray diffraction (XRD) techniques. Peaks of PL emission curves were shifted to higher wavelength side with boosted in their intensity confirms that the core QDs were epitaxially passivized by inorganic CdS shell. Shift of peaks towards higher 2θ angles in the XRD pattern before and after CdS shell growth confirms that the QD surface is altered by CdS shell. A detailed aspects of all these studies are presented in this paper. (author)

[en] Polymers have their own importance in the field of Solid state nuclear track detector (SSNTD) and in other allied science field. Among the several types of these detectors, polycarbonate detector such as Lexan detector is used for recording fission fragment tracks. Lexan polycarbonate (Lexan) is a promising polymer having lot of desirable properties for different application. When polymer is irradiated by electron, it induces modification in the physical and chemical properties of the polymer. The physical changes include microstructure, glass transition temperature, optical band gap, electrical conductivity etc. and the chemical changes include gas evolution, main chain scission, radical-radical combination etc. In amorphous polymer characterization, the free volume determination plays an important role. The better technique to get information about free volume is positron annihilation lifetime spectroscopy (PALS). In the present work, the modification in Lexan induced by 8 MeV electrons has been studied using PALS technique

[en] Orthophosphate-based phosphors have been used widely as efficient materials for the luminescence applications. Thermoluminescence (TL) properties of luminescent materials help us to find the suitability of the phosphors for the TL dosimetric application. In this work, a series of Dy${}^{3+}$ doped and Mn${}^{2+}$-codoped sodium yttrium phosphate Na${}_3$Y(PO${}_4$)${}_2$ phosphors were synthesized via a solid-state reaction method and thermoluminescence behavior were studied. To observe the effect of the dopant and codopants on phase purity and crystalline structure of phosphors, X-ray diffraction method analyses were carried. In addition, the morphological images were examined; chemical composition and functional groups were confirmed. Herein, the Dy${}^{3+}$-doped and Mn${}^{2+}$-codoped Na${}_3$Y(PO${}_4$)${}_2$ phosphors were irradiated by 1 kGy-dose γ-radiation and Na${}_3$Y(PO${}_4$)${}_2$:0.07Dy${}^{3+}$ showed a intense TL intensity peak at 178 °C, whereas Mn${}^{2+}$-Na${}_3$Y(PO${}_4$)${}_2$:0.07Dy${}^{3+}$, 0.07Mn${}^{2+}$ phosphors showed at 134 °C. The effect of codopant Mn${}^{2+}$ on the TL properties of Dy${}^{3+}$-doped Na${}_3$Y(PO${}_4$)${}_2$ phosphors and irradiation dose were investigated. The optimized Na${}_3$Y(PO${}_4$)${}_2$:0.07Dy${}^{3+}$ phosphor was showed a linear response to irradiation as a function of dose in the range of the 50 Gy–1.5 kGy. The glow curves were deconvolated and the TL kinetic parameters of phosphors were obtained by adopting various methods, revealing that the glow curves exhibited the second-order kinetics, and activation energies were calculated. The kinetic parameters of prepared samples were compared with the other TL materials. The obtained results confirm that the phosphors may have potential applications as TL dosimetry materials to measure low irradiation.

[en] The free volume properties of pristine and UV irradiated Lexan polycarbonate have been investigated using Positron Lifetime Spectroscopy (PLS). The decrease in o-Ps life time and free volume size of irradiated sample is attributed to free volume modification and formation of more stable free radicals. These free radicals are formed due to the breakage of C-O bonds in Lexan polycarbonate after irradiation. This is also supported by the decrease in the intensity of C-O bond after exposure to UV-radiation as studied from Fourier Transform Infrared (FTIR) spectroscopy and it also shows that benzene ring does not undergo any changes after irradiation.

[en] Gamma radiation assisted changes in stability and optical properties of CdTe colloidal quantum dots (QD) capped with 3-mercaptopropionic acid (MPA) molecules have been reported in this article. Synthesized QDs in water, using hydrothermal method, have been exposed to different gamma doses to see the changes in their light absorption and emission properties of QDs. Colour of light absorption and emissions are blue shifted for lower pH conditions followed by precipitation (after few days) of the whole dissolved materials as a response to irradiation due to photo-oxidation. Surprisingly, redshift has been observed for the same gamma doses when pH of QDs solution raised to higher number which also results in improved stability of QDs to with stand against irradiation (compared to acidic pH environment). Therefore, the solution of QDs with higher pH value is stable for future useful modifications of QD structures using radiation. These modifications may include the growth of single or multishells over core QDs by using this irradiation method to enhance their stability and optical properties. (author)

[en] Uranium is an important nuclear fuel for reactors. The more abundant ²³⁸U, which is fertile, is capable of serving as a source material for the production of fissile ²³⁹Pu in nuclear reactors by neutron capture followed by two beta decays. Neutron capture cross-section of the ²³⁸U is an important parameter for the design of any nuclear system based on ²³⁸U-²³⁹Pu fuel cycle. Therefore, it is necessary to have accurate knowledge of nuclear data of actinides such as yields fission products, neutron capture cross-sections and decay data including half-lives, decay energies, branching ratios etc. for the design of innovative reactor systems including fast breeder reactors and ADSs. In view of this, ²³⁸U (n, 2n)²³⁷U reaction cross-section has been determined using an activation and off-line γ-ray spectrometric technique at an average neutron energies of 8.04±0.30 and 11.90±0.35 MeV. The experiment was carried out using 14 UD BARC-TIFR Pelletron facility at Mumbai, India where in ⁷Li(p,n) reaction was used to generate neutron beam. The experimentally determined cross-section was compared with the latest available evaluated nuclear data libraries of ENDF/B-VII.0, JENDL 4.0, JEFF 3.1/A and CENDL-3.1 and found to be in good agreement. The ²³⁸U(n,2n)²³⁷U reaction cross section was also calculated theoretically using nuclear model based computer code TALYS 1.2 and compared with the experimental data. (author)

[en] Lexan polymer films irradiated with 550 keV Electron Beam (EB) were characterized using Wide Angle Xray Scattering (WAXS) data to study the microstructural parameters. The crystal imperfection parameters like crystal size < N>, lattice strain (g in %) and enthalpy (α) have been determined by Line Profile Analysis (LPA) using Fourier method of Warren.

[en] Nanostructures contribute vital applications for surface-based science including latent fingerprints (LFPs) detection and reconstruction. Fingerprints are unique to an individual, matching the finger prints help to identify culprits. Vanadium Pentoxide (V₂O₅) nanorods were synthesized via hydrothermal method using pomegranate peel extract as fuel, towards their use in fingerprint development. PXRD patterns confirmed the formation of orthorhombic V₂O₅ crystal structure. Raman vibration modes at 144 cm⁻¹ and 994 cm⁻¹ signifies the characteristic orthorhombic V₂O₅ structural formation, FTIR spectra shows vibration bands of V₂O₅, UV–vis spectroscopy shows an intrinsic absorption band at ∼418 nm corresponding to electron transitions (O_2p → V_3d). The energy band gap (E_g) estimated from absorption spectrum was found to be ∼2.35 eV. Formation of nanorods was observed from SEM micrographs and particle size was found to be 30 nm from TEM images. Photoluminescence emission studies were performed and yellow –orange (brown) emission was observed from CIE diagram. The characteristic brown/Yellow-orange color of V₂O₅ nanorods supports tracing of LFPs on many kind of surfaces in visible light which eliminates the need for illuminating source. Hence, V₂O₅ nanorods find potential application in Forensic sciences. (paper)

[en] 40 keV Synchrotron X-ray photons were made to fall on Lexan polycarbonate films at different exposure time. The low energy X-ray photons assisted modification in terms of physico-chemical properties of Lexan films were studied using Fourier Transform Infrared (FTIR) spectrophotometer, X-Ray Diffractogram (XRD), Vicker’s Microhardness Tester, Scanning Electron Microscope (SEM) and Contact Angle Meter. FTIR result mainly includes decrease in the C=C stretching and C-C stretching of aromatics after irradiation. XRD analysis shows a slight decrease in the crystallinity after irradiation. Vicker’s microhardness test reveals the decrement in microhardness of Lexan films after irradiation. SEM result shows irradiation induced changes in the surface morphology. Contact angle measurement shows increase in the water contact angle in irradiated Lexan films. (author)

[en] Bougainvillea flower extract was used as a fuel in solution combustion synthesis of pure and Nd³⁺ (1–9 mol %) doped vanadium pentoxides (V₂O₅) nanostructure. Powder x-ray Diffractogram, Scanning electron microscopy and Transmission electron microscopy images revealed the orthorhombic phase in Nd³⁺ doped V₂O₅ nanostructure. The additional peaks in Fourier Transform Infrared spectra and in Raman spectra were due to lattice distortion and mixed valence oxide in VO₄ led to structural and morphological changes. The synthesized Nd³⁺ doped V₂O₅ nanostructure exhibited good photocatalytic activity for the degradation of Methylene blue dye due to decrease in its work function as well as decrease in electron-hole recombination. (paper)