Energy dependence of photon-induced Kα and Kβ x-ray production cross-sections for some elements with 38≤Z≤51 in the energy range 20–50 keV

The energy dependence of photon-induced Kα and Kβ x-ray production (or x-ray fluorescence) cross-sections for Sr, Y, Mo, Ru, Pd, Ag, In and Sb elements has been studied in the energy range of 20–50 keV using Energy Dispersive X-Ray Fluorescence (EDXRF) Spectrometry. The photon energy dependence of K x-ray production cross-sections was measured with secondary excitation method. A radioisotope point source of ²⁴¹Am was employed to excite the K x-rays of secondary exciter elements. The L x-ray yields from Th and U were measured to determine I_oG (the intensity of exciter K x-rays falling on primary target). The measurements have been made by observing the x-ray emissions with the help of HPGe detector coupled with a multichannel analyzer. The areas of the Kα and Kβ spectral peaks, as well as the net peak areas, have been determined by a fitting process. The measured Kα and Kβ x-ray production cross-sections have been compared with calculated theoretical values in this energy regime. The present experimental results for all the elements were in general agreement with the theoretical values calculated using photoionization cross-sections, fractional rates (based on Hartree–Slater potentials) and fluorescence yields.     

Elemental analysis of selected Indian monazite ores by energy dispersive X-ray fluorescence /EDXRF/ spectroscopy

Analysis by Energy Dispersive X-ray Fluorescence spectroscopy of monazite ores from Kerala /Chavara and Manavalakurichi/, Orissa /Chattrapur/ and Tamil Nadu /Tirunelveli/ has been carried out for the determination of their elemental composition using¹⁰⁹Cd /annular/ and²⁴¹Am /disc/ radioisotope sources. The elements Y, Zr, Mo, Pb, Th and U were analyzed using a¹⁰⁹Cd source, and the elements La, Ce, Pr, Nd, Sm, Gd and Dy were analyzed using the²⁴¹Am source in side source geometry. Quntitative results on these 13 elements present in these ores were obtained by the EDXRF technique. It was seen that despite the diverse geological settings, there is remarkable similarity in the elemental composition of these ores, although some trace elements do show certain variations from sample to sample. These results are presented and discussed in this paper.     

High-precision energy-dispersive x-ray fluorescence analysis of manganese in ferromanganese

A high-precision x-ray fluorescence method for the determination of manganese in ferromanganese is described. The method involves excitation of the sample with a ¹⁰⁹Cd isotopic source and measurement with a high-resolution Si(Li) detector. To preserve the optimal energy resolution even at high count rates, the system incorporates a pulsed optical feedback preamplifier and a pulse pile-up rejector. The rejected pulses are corrected for by means of an adequate live-time correction circuit. Processing of the spectra is accomplished with the aid of a digital computer. The relative precision of the method is approximately 0.2%.     

A simple procedure for the fabrication of high activity beta-radiation sources of147Pm for use in beta-ray thickness gauges

A simple procedure is described for the fabrication of mCi level strong sources of¹⁴⁷Pm radioisotope on a noble metal substrate like Palladium as a source for β⁻-ray thickness gauge. The procedure is based on the principle of internal electro-deposition of¹⁴⁷Pm from aqueous solutions containing¹⁴⁷Pm³⁺ ions, using metallic magnesium for the purpose. Investigations conducted towards ascertaining the adherence of the¹⁴⁷Pm radioactivity onto the palladium substrate. Leaching studies conducted on these source indicated that the radioactive film is satisfactorily adherent to the palladium substrate, suggesting that the method can be used for fabricating satisfactorily safe high β⁻-activity sources of¹⁴⁷Pm contained in small active dimensions. Results of leaching studies keeping the sources fully immersed in boiling water for 15 minutes are also presented.     

A new approach to determine Pm in irradiated fuel solutions

Developments carried out in the Laboratory of Isotopic, Nuclear and Elementary Analyses in order to quantify ¹⁴⁷Pm in spent nuclear fuels analyzed at the CEA within the framework of the Burn Up Credit research program for neutronic code validation are presented here. This determination is essential for safety-criticality studies.The quantity and the nature of the radionuclides in irradiated fuel solutions force us to separate the elements of interest before measuring their isotopic content by mass spectrometry. The main objective of this study is to modify the separation protocol used in our laboratory in order to recover and to measure the ¹⁴⁷Pm at the same time as the other lanthanides and actinides determined by mass spectrometry.A very complete study on synthetic solution (containing or not ¹⁴⁷Pm) was undertaken in order to determine the yield of the various stages of separation carried out before obtaining the isolated Pm fraction from the whole of the elements present in the spent fuel solutions. With the lack of natural tracer to carry out the measurement with the isotope dilution technique, the great number of isotopes in fuel, the originality of this work rests on the use of another present lanthanide in fuel to define the output of separation. The yields were measured at the conclusion of each stage of separation with two others lanthanides in order to show that one of them could be used as a tracer to correct the measurement of the ¹⁴⁷Pm with the separation yield. The total yield (at the conclusion of the two stages of separation) was measured at the same time by ICP-MS and liquid scintillation. This last determination made it possible to validate the use of the ¹⁴⁷Sm (natural) to measure the ¹⁴⁷Pm in ICP-MS since the outputs determined in liquid scintillation and ICP-MS (starting from the radioactive decrease of the source having been used to make the synthetic solution) were equivalent. It is the first time that such measurement is performed in ICP-MS.The measurement of the ¹⁴⁷Pm was finally taken on fuels UOx and MOx by using the ¹⁵³Eu like a tracer of the separation yield. The results obtained are in very good agreement with those obtained from neutronic calculation code.     

Sr4PbPt4O11, the first platinum oxide containing Pt2 ions

We report the synthesis and crystal structure of the new compound Sr₄PbPt₄O₁₁, containing platinum in highly unusual square pyramidal coordination. The crystals were obtained in molten lead oxide. The structure was solved by X-ray single crystal diffraction techniques on a twinned sample, the final R factors are R=0.0260 and wR=0.0262. The symmetry is triclinic, space group P1¯, with , , , α=90.421(3)°, β=89.773(8)°, γ=90.140(9)° and Z=2. The structure is built from dumbell-shaped Pt₂O₉ entities formed by a dinuclear metal-metal bonded Pt₂⁶⁺ ion with asymmetric environments of the two Pt atoms, classical PtO₄ square plane and unusual PtO₅ square pyramid. Successive Pt₂O₉ entities deduced from 90° rotations are connected through the oxygens of the PtO₄ basal squares to form [Pt₄O₁₀⁸⁻]_∞ columns further connected through Pb²⁺ and Sr²⁺ ions. Raman spectroscopy confirmed the peculiar platinum coordination environment.     

Bismuth as a general internal standard for lead in atomic absorption spectrometry

Bismuth was evaluated as internal standard for Pb determination by line source flame atomic absorption spectrometry (LS FAAS), high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) and line source graphite furnace atomic absorption spectrometry (LS GFAAS). Analysis of samples containing different matrices indicated close relationship between Pb and Bi absorbances. Correlation coefficients of calibration curves built up by plotting A^Pb/A^Biversus Pb concentration were higher than 0.9953 (FAAS) and higher than 0.9993 (GFAAS). Recoveries of Pb improved from 52–118% (without IS) to 97–109% (IS, LS FAAS); 74–231% (without IS) to 96–109% (IS, HR-CS FAAS); and 36–125% (without IS) to 96–110% (IS, LS GFAAS). The relative standard deviations (n = 12) were reduced from 0.6–9.2% (without IS) to 0.3–4.3% (IS, LS FAAS); 0.7–7.7% (without IS) to 0.1–4.0% (IS, HR-CS FAAS); and 2.1–13% (without IS) to 0.4–5.9% (IS, LS GFAAS).     

Synthesis, structure, magnetic susceptibility and Mössbauer and Raman spectroscopies of the new oxyphosphate Fe0.50TiO(PO4)

A new iron titanyl oxyphosphate Fe_0.50TiO(PO₄) was synthesized by both solid-state reaction and Cu²⁺-Fe²⁺ ion exchange method. The material was then characterized by X-ray diffraction, Mössbauer spectroscopy, magnetic susceptibility measurements and Raman spectroscopy. The crystal structure of the compound was refined, using X-ray powder diffraction data, by Rietveld profile method; it crytallizes in the monoclinic system, space group P2₁/c (No.14), with , , , β=120.36°(1), and Z=4. The volume of the title compound is comparable to those of the M_0.50^IITiO(PO₄) series, where M^II=Mg, Co, Ni and Zn. The framework is built up from [TiO₆] octahedra and [PO₄] tetrahedra. [TiO₆] octahedra are linked together by corners and form infinite chains along the c-axis. Ti atoms are displaced from the center of octahedral units showing an alternating short distance (1.73 Å) and a long one (2.22 Å). These chains are linked together by [PO₄] tetrahedra. Fe²⁺ cations occupy a triangle-based antiprism sharing two faces with two [TiO₆] octahedra. Mössbauer and magnetic measurements show the existence of iron only in divalent state, located exclusively in octahedral sites with high spin configuration (t_2g⁴e_g²). Raman study confirms the existence of Ti-O-Ti chains.     

Interlayer adsorption of polyvinylpyrrolidone on montmorillonite

Two methods (x-ray diffraction and desorption of ¹⁰⁹Cd and ⁸⁵Sr) were used to provide indirect evidence for the adsorption of polyvinylpyrrolidone (PVP) on the surface of montmorillonite. It was shown that by decreasing the number of solvent layers in the interlayer distance the amount of adsorbed PVP was decreased, indicating that attachment of the polymer to the tetrahedral sheets is likely to occur. Desorption of radio-nuclides from calcium and sodium montmorillonites confirmed this hypothesis.     

Barrelane-like germanium clusters in Eu3Ge5: Crystal structure, chemical bonding and physical properties

Formation and crystal structure of the binary germanide Eu₃Ge₅ were investigated in detail. The compound forms peritectically at 1008 °C and does not undergo any phase transition down to room temperature. The crystal structure was determined first from X-ray powder diffraction data and was later confirmed by single-crystal X-ray diffraction: structure type Pu₃Pd₅, space group Cmcm (no. 63), , , . The main building blocks are Ge₅⁶⁻ cluster anions surrounded by Eu²⁺ cations. The nearly tetragonal-pyramidal shape is suggested by the interatomic distances. Contrary to that, the bonding analysis with the electron localization function (ELF) reveals only two- and three-bonded germanium atoms forming a strongly distorted [1.1.1]-barrelane-like cluster. Despite the formal electron deficiency, compared to the barrelane C₅H₈, the electron counting in the cluster anion and its conformation cannot be interpreted applying the Wade's rules. In accordance with the calculated electronic density of states, Eu₃Ge₅ shows a metal-like temperature dependence of the electrical resistivity with a sharp change of ρ(T) slope at the Néel point. Above the Néel point the inverse magnetic susceptibility reveals Curie-Weiss behavior with an effective moment of 8.11 μ_B (Eu²⁺, 4f⁷ configuration) in agreement with the analysis of the chemical bonding. The 4f⁷ electronic configuration of europium is confirmed by Eu-L_III X-ray absorption spectroscopy.     

Anodically oxidised aluminium layer as a useful substrate for the fabrication of147Pm sources for beta-ray thickness gauges

An anodically oxidised layer of aluminium was found to be a satisfactory substrate for holding millicurie amounts of carrier-free¹⁴⁷Pm activity, which is used as a source of -radiation in -ray thickness gauges. The sources fabricated by this method showed satisfactory performance regarding leaching and adherence of the radioactivity held up in the oxide layer. Details regarding the anodic oxidation conditions used for making these source substrates are given. Leaching studies conducted on these sources indicated influence of the acid concentration at which¹⁴⁷Pm activity was deposited in the oxide layer. Better performance characteristics of these sources could be achieved whenever¹⁴⁷Pm activity was absorbed in the oxide layer under near neutral conditions of acidity.     

Structural and magnetic properties of perovskite Ca3Fe2WO9

A complex perovskite with composition Ca₃Fe₂WO₉ has been synthesised, and the temperature evolution of nuclear and magnetic structures investigated by neutron powder diffraction. It was shown that at room temperature this compound adopts a monoclinic perovskite structure belonging to space group P12₁/n1 (, , ), β=90.04(2)°). The partial B-site ordering, of the Fe⁺³ and W⁺⁶ cations, at (2c) and (2d) sites was determined. At low temperatures the magnetic diffraction peaks were registered and a possible model for the magnetic structure was proposed in accordance with the ferrimagnetic properties of the title compound. The magnetic structure is defined by a propagation vector k=(1/2,1/2,0) and can be described as an array of ferromagnetic (20−1) layers, which couple antiferromagnetically to each other. All the Fe moments within a layer are aligned parallel (or anti-parallel) to the c-axis. The structural and magnetic features of this compound are discussed and compared with those of some other quaternary oxides A₃Fe₂WO₉ (A=Ba, Sr, Pb).     

Abtrennung von Palladiumspuren aus Reinstplatin nach Neutronenaktivierung unter Berücksichtigung weiterer Spurenverunreinigungen

As first step the separation of¹⁰⁹Pd (T1/2=13.5 h) after neutron activation from the highly radioactive platinum is performed after addition of Pd carrier as chloro-complex on strong basic anion-exchangers. The simultaneous separation of some further short living radionuclides of trace element stakes place. After a purification step with dimethylglyoxime decontamination factors up to 10⁶ are attainable. Using an Ge(Li)-detector and evaluating theγ-irradiation of the¹⁰⁹Pd daughter^109mAg 0.4 μg of Pd could be determined with a standard deviation of 6.5%.     

Analysis of trans-Resveratrol in Iranian Grape Cultivars by LC

In this study, trans-resveratrol levels were determined in 147 Iranian grape cultivars using a modified extraction and gradient HPLC procedure with photodiode array detection. It was found that 41 out of 147 cultivars contained significant levels of trans-resveratrol. The detected amounts ranged from 0.98 to 6.25 mg kg^?1 fresh weight with a mean value of 3.59 (white grapes) and 3.08 mg kg^?1 (red grapes), respectively.     

Chemical study on the separation and purification of promethium-147

A chemical process for the separation of¹⁴⁷Nd/¹⁴⁷Pm from fission products of synthetic radioactive waste solution has been developed. The process includes: (1) denitration, (2) removal of high concentration of uranium by 30% TBP/kerosene extraction, (3) removal of⁹⁵Nb,¹⁰³Ru,¹³⁷Cs and part of⁹⁰Sr by 50% TBP/dodecane extraction, (4) separation of¹⁴⁷Nd/¹⁴⁷Pm from part of⁹⁰Sr and⁹⁵Zr by oxalic acid precipitation, and (5) removal of¹⁴⁴Ce by mixture of 0.4M D2EHPA and 0.2M TBP extraction. Experimental results indicate that the recovery of¹⁴⁷Nd/¹⁴⁷Pm in the final separated solution is about 90%. The purification of¹⁴⁷Nd and¹⁴⁷Pm from some other rare earth elements, viz.¹⁵³Sm,¹⁵⁴Eu and¹⁴⁴Ce was further investigated by using a Dowex 50W×8 ion-exchanger. Parameters of flow rate, eluent concentration and pH were examined. The results show that the recovery and radionuclide purity of¹⁴⁷Nd plus¹⁴⁷Pm under the present separation conditions are 77.8% and 98.6% for diethylenetriaminepentaacetic acid (DTPA) and 87.3% and 99.5% for nitrilotriacetic acid (NTA), respectively.     

Hydroxide des Natriums,Kaliums und Rubidiums: Einkristallzüchtung und röntgenographische Strukturbestimmung an der bei Raumtemperatur stabilen Modifikation

Hydroxides of Sodium, Potassium, and Rubidium: Crystal Growth and X-ray Structure Determination of the Modification Stable at Room Temperature NaOH powder can be recrystallized at 523 to 473 K from NH₃ at 6 kbar pressure within 10 d in the form of transparent crystal plates which are very sensitive to mechanical deformation; they split into slices. Under comparable conditions the protolysis of KNH₂ and RbNH₂, with K(H₂O)OH and Rb(H₂O)OH, respectively, at temperatures <423 K and <365 K leads to platelets of crystals of KOH and RbOH. The crystal growth was carried out within the range of stability of the corresponding stable room temperature modification. The x-ray diffraction of single crystals gives new information about the atomic arrangement in the three compounds: For NaOH the positions of the H atoms result (measurements at 294 K and 147 K), the x-ray structure of NaOH has been known as to the Na and O arrangement. It is of the TlI-type structure. The OH^? ions are quadratic pyramidaly coordinated by Na⁺ ions. They form linear Na? O? H groups with the Na⁺ ion at the top of the pyramide. This gives H double layers within the structure; they are responsible for the easy cleavage of the crystals perpendicular to the direction [010]. KOH and RbOH are isotypic. They have a monoclinically deformed NaCl-type structure for the heavier atoms. The OH^? ions librate at room temperature. So the positions of the H atoms even in KOH could not be detected by x-ray structure determination.     

Extended networks, porous sheets, and chiral frameworks. Thorium materials containing mixed geometry anions: Structures and properties of Th(SeO3)(SeO4), Th(IO3)2(SeO4)(H2O)3·H2O, and Th(CrO4)(IO3)2

Three novel Th(IV) compounds containing heavy oxoanions, Th(SeO₃)(SeO₄) (1), Th(IO₃)₂(SeO₄)(H₂O)₃·H₂O (2), and Th(CrO₄)(IO₃)₂ (3), have been synthesized under mild hydrothermal conditions. Each of these three distinct structures contain trigonal pyramidal and tetrahedral oxoanions. Compound 1 adopts a three-dimensional structure formed from ThO₉ tricapped trigonal prisms, trigonal pyramidal selenite, SeO₃^2-, anions containing Se(IV), and tetrahedral selenate, SeO₄^2-, anions containing Se(VI). The structure of 2 contains two-dimensional porous sheets and occluded water molecules. The Th centers are found as isolated ThO₉ tricapped trigonal prisms and are bound by four trigonal pyramidal iodate anions, two tetrahedral selenate anions, and three coordinating water molecules. In the structure of 3, the Th(IV) cations are found as ThO₉ tricapped trigonal prisms. Each Th center is bound by six IO₃^1- anions and three CrO₄^2- anions forming a chiral three-dimensional structure. Second-harmonic generation of 532 nm light from 1064 nm radiation by a polycrystalline sample of 3 was observed. Crystallographic data (193 K, MoKα, λ=0.71073): 1; monoclinic, P2₁/c; , , , β=103.128(1), Z=4, R(F)=2.47% for 91 parameters with 1462 reflections with I>2σ(I); 2, monoclinic, P2₁/n, , , , β=100.142(2), Z=4, R(F)=4.71% for 158 parameters with 2934 reflections with I>2σ(I); 3, orthorhombic, P2₁2₁2₁, , , , Z=4, R(F)=2.04% for 129 parameters with 2035 reflections with I>2σ(I).     

K x-ray emission in gas- and solid targets in close heavy ion-atom collisions

Impact parameter dependentK x-ray emission from both collision partners in²⁰⁸Pb⁺²⁶ →¹²⁰Sn and Xe collisions at 3,6 MeV/N projectile has been investigated. In solid target collisions the Sn-K emission yield shows impact parameter dependent structures. These structures are interpreted in terms of post-collisional capture processes. TheK x-ray emission from the heavier collision partner related to the 1s σ vacancy production, is found to be dependent on the primary projectile outer-shell configuration.     

Extending framework based on the linear coordination polymers: Alternative chains containing lanthanum ion and acrylic acid ligand

One-dimensional alternative chains of two lanthanum complexes: [La(L¹)₃(CH₃OH)(H₂O)₂]·5H₂O (L¹=anion of α-cyano-4-hydroxycinnamic acid ) 1 and [La(L²)₃(H₂O)₂]·3H₂O (L²=anion of trans-3-(4-methyl-benzoyl)-acrylic acid) 2 were synthesized and structurally characterized by single-crystal X-ray diffraction, element analysis, IR and thermogravimetric analysis. The crystal structure data are as follows for 1: C₃₁H₃₆LaN₃O₁₇, triclinic, P-1, , , , α=72.7960(10)°, β=83.3820(10)°, γ=67.1650(10)º, Z=2, R₁=0.0377, wR₂=0.0746; for 2: C₃₃H₃₇LaO₁₄, triclinic, P-1, , , , α=81.145(2)°, β=87.591(2)°, γ=67.345(5)°, Z=2, R₁=0.0869, wR₂=0.220. 1 is a rare example of the alternative chain constructed by syn-syn and anti-syn coordination mode of carboxylato ligand arranged along the chain alternatively. La(III) ions in 2 are linked by two η³-O bridges and four bridges (two η²-O and two η³-O) alternatively. Both of the linear coordination polymers grow into two- and three-dimensional networks by packing through extending hydrogen-bond network directed by ligands.     

Crystal structure, magnetic susceptibility and Mössbauer spectroscopy of the mixed-valence iron phosphate Na1/2Cu4/3Fe2(PO4)3

Single crystals of a new mixed-valent iron phosphate Na_1/2Cu_4/3Fe₂(PO₄)₃ have been synthesized by a flux method and structurally characterized from X-ray diffraction data. Crystal data: space group ; ; ; ; α=105.881(1)°; β=107.202(1)°; γ=101.467(1)°; Z=2; R₁=0.03; wR₂=0.093. The three-dimensional structure was found to be closely related to that of the well known Howardevansite structural type. It results from infinite chains of CuO₅ and FeO₆ polyhedra, joined together by (Cu,□)O₆ octahedra and PO₄ tetrahedra by corner-sharing. The large cavities in framework are occupied by Na⁺ ions. The magnetic susceptibility study revealed an antiferromagnetic behavior with Neel temperature of approximately 40 K. The Mössbauer spectroscopy confirmed the presence of iron in both +2 and +3 oxidation states.