Nano ceramics of undoped and Eu and Tb-doped strontium molybdate (SMO) were synthesized via co-precipitation route and characterized by XRD, SEM and DLS techniques. It was observed that the average particle size for the samples was 90 nm. A bluish emission attributed to the tetrahedral molybdate moiety was observed for the undoped system. The single-doped sample Eu3+:SMO gave orange-red emission, whereas the Tb3+:SMO sample showed blue-green emission. From the emission data, the site symmetry of the ions was estimated. Based on the emission data of single-doped samples, the co-dopant ions concentrations were tuned to extract white light emission from the system. It was observed that when doped with 0.5 mol% Eu3+ and 1 mol% Tb3+ and excited with 230 nm, the system gave a 'cool day light' white light emission with a correlated color temperature (CCT) 6863 K. (C) 2015 Elsevier B.V. All rights reserved.

A brief account of the luminescence studies of gemstones ruby,chryso beryl and diamond are given The luminescence of ruby primarily arises due to trivalent chromium impurity, where as the nitrogen-vacancy complexex are the main centres of luminescence in diamond. In the case of diamond surface fluorescence mapping under deep UV excitation is invaluable in detecting the lab grown diamonds.

The utility of plastic/glass containers in place of regular sample cups made of high density polyethylene for the EDXRF determination of uranium has been examined. A series of uranium solution standards have been prepared and calibrated using different containers. For U solution in plastic cups with thin mylar film base, linearity between U La X-ray intensity and its concentration is observed upto U <= 20 mg/mL; for higher concentrations, non-linear trend is observed, indicating matrix absorption effects. For U solution in plastic vials, similar behaviour is observed, with reduced matrix absorption. In the case of U solutions in sealed plastic vials, the reduction in the intensities of U X-rays of standard solutions is about 30-70% of those for U in unsealed vials. In the case of glass vials, the intensity of U X-ray peak decreases drastically as compared to that for U in plastic cups with thin mylar film base. The present study suggest the utility of sealed plastic vials for the fast preliminary determination of uranium in low active process / laboratory waste solutions with a precision of about 5-15%.

This paper describes a graphite furnace atomic absorption spectrometric (GFAAS) method for the direct determination of chloride in uranium. The method is based on an indirect approach of monitoring excess silver present in a uranium solution after precipitation of chlorine as AgCl. It was found that interference from other halides, i.e., Br- and I-, could be overcome by prior addition of Cu2+ to the sample solution containing 15% (v/v) of ethanol. This removes Br- and I- due to the formation of insoluble cuprous salts. Using the optimized conditions of copper and ethanol addition, chloride can be determined in the concentration range of 0.5-50 ppm in uranium with a precision of +/- 15% in the presence of halides.

U 6 + doped BaSO 4 samples were synthesized by precipitation route. PL, TL and EPR investigations of γ and self α irradiated samples were carried out. PL spectra of these samples give structured broad band peaking around 518 nm with five vibronic bands centred around 498·4, 516·0, 533·7, 554·0 and 575·1 nm, respectively and the average frequency of symmetric stretching of O=U=O in the ground electronic state was found to be 674 cm −1 . Trap level spectroscopic studies of U doped BaSO 4 give glow peaks at 411, 488 and 512 K, respectively and their spectral characteristics are typical of UO _2^2+ emission. EPR studies of γ -irradiated U 6+ :BaSO 4 sample have shown the presence of sulphoxy centred radicals like SO _4^- and SO _3^- in addition to OH • , O _3^- and SH 2− . TSL peaks at 411 and 488 K were correlated with thermal destruction of SO _4^- and SO _3^- radicals.

Americium from analytical solid waste containing U and metallic impurities was separated using hollow fiber supported liquid membrane (HFSLM) technique impregnated with DHOA–TODGA from nitric acid medium. An aliquot of 5 g of the solid waste containing Am (19.95 mg) as minor actinide and of U (2,588 mg), Fe (1,360 mg), Ca (1,810 mg) and Na (3,130 mg) as major impurities was processed. The feed solution obtained after the dissolution of the residue in ~4 M HNO3 was passed through HFSLM module. In the first stage using 1 M DHOA–dodecane U was recovered while Am and other impurities were left in the raffinate. In the second stage, 0.5 M DHOA + 0.1 M TODGA/dodecane was used for the separation of Am from other impurities. Though, majority of the elements were separated in this cycle, Ca was co extracted along with the americium. CMPO extraction chromatographic technique was used for further separation of americium from Ca. Significant decontamination factors were achieved in this three step separation process with respect to U, Fe, Na and Ca with ~77 % recovery of americium.

White light emitting Sr2SiO4:Eu2+ nanoparticles were prepared using reverse micellar route using Tergitol as a surfactant. The systems were characterised by X-ray diffraction, scanning electron microscopy (SEM), photoluminescence, thermoluminescence (TL), and electron paramagnetic resonance (EPR) spectroscopy. SEM shows the formation of silicate nanorods. Two emission bands of bluish-green at 490nm (S(I)) and of orange-red at 605nm (S(II)) were observed. The two emission bands are assigned to the 4f-5d transition of Eu2+ ions in two different cation sites in alpha '-Sr2SiO4 orthorhombic lattices. Gamma-irradiated Sr2SiO4:Eu showed the presence of three TL glow peaks at 437, 487K and weak peak at 540K; however, no glow was observed in the undoped sample. Reduction of Eu3+ to Eu2+ is confirmed by EPR spectroscopy.

An inductively coupled plasma atomic emission spectrometry (ICP-AES) method has been developed for the trace metal characterization of high-level liquid waste solutions originating from reactor fuels of burn-up varying from 1000 to 15,000 MWD per ton. After optimization of various analytical, parameters, the method was validated by analysis of three synthetic samples containing elements in the composition range as expected in high-level radioactive liquid waste (HLLW). The analytical results obtained by ICP-AES from simulated high-level liquid waste (SHLW) of a pressurized heavy water reactor (PHWR), research reactor (RR), fast breeder reactor (FBTR), and high-level radioactive liquid waste (HLLW) from the Plutonium Resprocessing Plant (PREFRE) and Waste Immobilisation Plant (WIP) in Tarapur, India, are also included.

CaSO(4):Dy, CaSO(4):(Dy, Bi) and CaSO(4):Bi phosphors were prepared through re-crystallization method. Thermoluminescence (TL) characteristics of these phosphor samples were investigated. The radiation induced radical ions formed in these phosphors were investigated using electron paramagnetic resonance (EPR) spectroscopy. The main signals observed in both CaSO(4):(Dy, Bi) and CaSO(4):Bi were identified as SO(4)(-) (II), SO(4)(-) (⊥) and SO(3)(-) (isotropic) with "g" values 2.023, 2.0089 and 2.004, respectively. In order to understand the TL mechanism, CaSO(4):(Dy, Bi) phosphor samples were annealed between 100 and 250 °C and their EPR spectra were studied. It was observed that EPR signal intensities reduce drastically in 250 °C annealed phosphor confirming the role of SO(4)(-) and SO(3)(-) types of defect centers in the dosimetric peak. The reduction in the TL sensitivity with increase in Bi(3+) co-dopant in the phosphor samples was correlated with quenching of TL by Bi(3+) ions rather than the reduction in the concentration of the above defect centers. An effort was also made to use the Bi(3+) co-doped CaSO(4):Dy phosphor for dosimetry of chilled or frozen food irradiation.

Electron paramagnetic resonance (EPR) investigations of Li2C2O4, Na2C2O4 mixed in proportion 1:0, 0:1, 1:1, 2:1 and 3:1 were carried out to measure the absorbed dose from photons and thermal neutrons in a mixed radiation field. A single line spectrum of CO2− radical anion centered around g=2.0045±0.0005 was obtained in the respective cases on gamma and neutron irradiation. Except Na2C2O4, other mixtures had shown increase in line width on neutron irradiation possibly due to relaxation effects. Of all combinations, the 2:1 mixture is the more sensitive material for gamma and thermal neutrons. Intensity of CO2− radical signal in 2:1 Li2C2O4:Na2C2O4 mixture was found to be linear from 0.006 to 11kGy for gamma and 40–1530kGy for thermal neutron doses. Radical signal was found to be stable over a period of 300 days with marginal fading of less than 1 percent. Experimental results thus obtained suggest 2:1 Li2C2O4:Na2C2O4 mixture as the potential neutron dosimeter for medium and high dose range.

An EDXRF technique for the determination of four important rare earth impurities, viz., Eu, Dy, Sm and Gd, at 20-1000 μg/ml in aqueous medium as well as in the presence of uranium has been reported. The conditions have been optimized for the simultaneous determination of these elements. The limits of detection for the analytes in aqueous solutions are determined to be 20 μg/ml. In order to achieve lower limits of detection, a novel method based on polyvinyl alcohol films containing these rare earths has been established. Four uranium oxide samples have been analysed by EDXRF as well as inductively coupled plasma- atomic emission spectrometry after chemical separation of uranium. The results are in good agreement.

The synthesis and optical properties of Eu 3+ in SrAl 12 O19 nanophosphor have been studied. All the phosphors were prepared by combustion synthesis and characterized by XRD, EDS, TGA, DTA, particle size analyzer and photoluminescence measurements are carried out. The XRD characterization shows the formation of hexagonal crystalline SrAl 12 O19 matched with the JCPDS file no. 00-026-0976. SEM and EDS show the formation of nanophosphor and the presence of aluminium, strontium, europium and oxygen. Luminescent characterization shows the emission at 580 nm (yellow) in the visible region by the 858 nm infrared excitation. These results indicate that the Eu doped material is a promising yellow colour fluorescence powder used in colour display or yellow-LED light device using LASER diode as an excitation source.

Polycrystalline Na 3 SO 4 F:Eu and NaMgSO 4 F:Eu phosphors prepared by a wet chemical method has been studied for its photoluminescence (PL) characteristics. PL emission spectra of Na 3 SO 4 F and NaMgSO 4 F, phosphors under 393 nm excitation (mercury-free excitation) shows very strong prominet peak at 591 nm due to 5 D o → 7 F l transition and 613 nm corresponding to 5 D o → 7 F 2 transition in the red region of the spectrum. The PL emission spectra of Eu 3+ ion in the Na 3 SO 4 F:Eu and NaMgSO 4 F:Eu phosphors are applicable for mercury free lamp industries.

The calcium aluminates doped with Eu ions, Ca5Al8O14: Eu, phosphors are prepared by the combustion method. The formation of crystalline aluminates was confirmed by X-ray diffraction pattern. The prepared phosphors were characterized by SEM, TGA, DTA, particle size analyzer and Photoluminescence (PL) techniques. From the UV-excited luminescence spectra it was found that the Eu ions acts as a luminescent centre with luminescence at the blue (λ max = 470 nm) region due to 4f 65d 1 → 4f 7 transition. The excitation spectra show the broad band at 355 nm wavelength (λ em = 470 nm). The excitation 355 nm is a mercury free excitation and therefore Ca5Al8O14: Eu may be useful for the solid state lighting phosphor in lamp industry.

A new red emitting phosphor, ZnMgAl10O17:Eu, was prepared by a novel urea templated combustion route. Photoluminescence and crystalline properties were investigated as function of Eu doping levels. It was found that under UV excitation with a wavelength of 254nm, the phosphor gave emission at blue (λmax=452nm) and red (λmax=613nm) region due to 4f65d1→4f7 and 5D0→7F2 transition respectively. Whereas the ZnMgAl10O17:Eu also gave emission at 580, 590, 599, 655, 700 and 770nm in the red region of the spectrum due to 5D0→7Fj (j=0, 1, 2, 3, 4, 5). The maximum emission intensity of the ZnMgAl10O17 phosphors occurred at a Eu concentration of 1mol%. The scanning electron microscopy and particle size analysis indicated that phosphor particle have an irregularly shaped morphology, the average particle size was found to be approximately 630nm.

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The synthesis and optical properties of Eu 3+ in SrAl 12 O19 nanophosphor have been studied. All the phosphors were prepared by combustion synthesis and characterized by XRD, EDS, TGA, DTA, particle size analyzer and photoluminescence measurements are carried out. The XRD characterization shows the formation of hexagonal crystalline SrAl 12 O19 matched with the JCPDS file no. 00-026-0976. SEM and EDS show the formation of nanophosphor and the presence of aluminium, strontium, europium and oxygen. Luminescent characterization shows the emission at 580 nm (yellow) in the visible region by the 858 nm infrared excitation. These results indicate that the Eu doped material is a promising yellow colour fluorescence powder used in colour display or yellow-LED light device using LASER diode as an excitation source.

Ultrafine M5(PO4)3F:Dy3+ (M = Ca, Ba) phosphors were prepared via combustion process using metal nitrates as precursors. The formation of crystalline phosphate was confirmed by X-ray diffraction pattern. The PL excitation spectra show the excitation peaks observed at 250 to 400 nm due to f → f transition of Dy3+ ion, which are useful for solid-state lighting purpose (mercury free excitation). The PL emission of Dy3+ ion by 348 nm excitation gave an emission at 489 nm (blue), 582 nm (yellow) and 675 nm (red). All the characteristics of BYR emissions like BGR indicate that Dy doped Ca5(PO4)3F and Ba5(PO4)3F phosphors are good candidates that can be applied in solid-state lighting phosphor (mercury free excited lamp phosphor) and white light LED.

. Electron Paramagnetic Resonance (EPR) technique is useful to quantify the paramagnetic species in any matrix. The unpaired electrons present in paramagnetic materials have non – zero spin value, have an associated spin magnetic moment. When such a system is subjected to an external magnetic field, electronic Zeeman splitting of ground level state occurs. On application of suitable stimulant microwave energy, the electrons flip between the Zeeman levels of ground state, result in resonant absorption of the microwave energy. The intensity of resonant absorption signal is proportional to the concentration of the unpaired electrons in the irradiated material, could lead to possible use of such materials in EPR dosimetric applications. New materials were investigated for EPR dosimetry, wherein the radiation induced paramagnetic species retains the radiation signatures, lead to idea on radiation dose. Few of the materials have been identified as prospective EPR dosimeters. The radiation induced radical in Li 2 CO 3 powder material being paramagnetic in nature (signals at g = 2.0036 and at g = 2.0006) and radical concentration varying as a function of irradiation dose, led to its identification for possible use in EPR dosimetric applications. Besides, during the neutron irradiations, the reaction 6 Li (n, α ) 3 H, led to the yield of radicals many folds higher compared to that of gamma irradiation. Thus, the commonly available Li 2 CO 3 material has been assessed for the EPR dosimetric response in gamma and neutron environments. 4 Na 2 C 2 4 mixtures measure the radiation from γ photons and thermal neutrons in a mixed radiation field. single line spectrum of radical 2.0045 ± 0.0005 was found on gamma and neutron irradiations. Of all the mixture combinations, the 2:1 mixture was found more sensitive for gamma / thermal neutrons. Intensity of CO 2- radical signal was found linear from 6 Gy – 11 kGy for gamma and 40 – 1500 kGy for thermal neutron flux. The radiation induced radical signal was found to be stable over a period of 300 days with marginal fading of < 1 %. The results of EPR dosimetry suggest that the Li 2 C 2 O 4 : Na 2 C 2 O 4 mixture as the potential neutron dosimeter for high range dosimetry. The effect of gamma dose irradiation on sodium succinate was studied by EPR technique. It was observed that the radiation induced CO 3 − radical (g = 2.00357) as linear in signal – dose response, in 35 Gy – 4.4 kGy. Thus, sodium succinate powder samples could be used in EPR dosimetry, since CO 3 − radicals have been found stable for more than 6 months, post-irradiation. Solid State Nuclear Track Detector (SSNTD) material Tuffak polycarbonate film was studied for prospective EPR dosimetry, feasibility studies were carried out on gamma irradiated SSNTD film. The first derivative EPR spectra of irradiated Tuffak polycarbonate samples contained a singlet, signal at g = 2.00415. The signal was identified as CO 33 − from earlier reports. The EPR signal intensity of CO 33 − (g = 2.00415) was found linear in signal – dose response in 10 - 80 kGy. The present paper gives an update of newer EPR dosimetric materials that have been investigated, after a brief introduction to the basic principles of EPR. Further, prospective dosimetric materials with their suitability for applications in EPR dosimetry have been discussed.

Eu-activated Y2O3 phosphors were prepared by combustion synthesis and also by precipitation techniques. Photoluminescence and X-ray excited luminescence of prepared Y2O3:Eu phosphor, under two different techniques were compared and reported in this paper. Y2O3:Eu3+ phosphor were prepared by precipitation technique followed by annealing at 900°C. It gives cubic nature of the particle that may be more favourable for high lumen output. X-ray excited luminescence of Y2O3:Eu3+ phosphors also reported in this paper.