Role of an in-house designed crucible in the fabrication of isotopically enriched 28Si target for an in-beam γ-ray spectroscopy experiment.

In the present work, an in-house designed special crucible was developed to fabricate isotopically enriched 28Si targets for a γ-ray spectroscopy experiment. Initially, the crucible was tested with natural Si and then utilized to fabricate isotopically enriched 28Si targets of thickness ∼500 µg/cm2 (∼2.15 µm). The fabricated targets were uniform in thickness and had very little contamination. In addition, one of the fabricated targets was successfully utilized in an in-beam γ-ray spectroscopy experiment. The technique employed in the present work not only facilitates the fabrication of stable and pure targets but also minimizes the wastage of the source material. As a result, these efforts pave the way for future fabrication of low-abundance isotopically enriched nuclear physics targets.

Study of chemical effects on L X-rays spectra of 59Pr compounds using high resolution WDXRF and EDXRF measurements.

Chemical effects on L X-rays spectra of PrF3, PrCl3, PrBr3, Pr2O3, Pr6O11 and Pr2(SO4)3 compounds have been investigated from measured ILi/ILα (i = l and ß6), ILj/ILß1 (j = Î·, γ5 and γ1), ILk/ILγ1 (k = Î³5 and η) intensity ratios using high resolution poly-chromatic WDXRF, and monochromatic excitation by 6.49 keV in vacuum (10-2 Torr) and Ag Kαß (22.581 keV) X-rays photons in EDXRF spectrometers. The experimental results clearly exhibit significant variation in measured intensity ratios of L X-ray components of investigated compounds from pure elemental form and theoretically predicted values evaluated using different atomic parameters. Furthermore, the change in inner shell/subshells binding energy resulting from the transitions of outer shell/subshell electrons is also inferred from the shifts of order ∼0.1-0.70 eV in Ll, Lß2 and Lγ1 components of PrF3, PrCl3, PrBr3, Pr2O3, Pr6O11 and Pr2(SO4)3 WDXRF spectra relative to pure 59Pr. The variation in intensity ratios and shift in Ll, Lß2 and Lγ1 X-ray components of 59Pr compounds are attributed to crystal defects, structural effects and exchange interactions between core and valence electrons of different ligands attached to central 59Pr atom. The reliable experimental data would be helpful in the theoretical interpretation of standard reference data for inner-shell vacancy decay parameters used in X-ray fluorescence analysis of compound samples.

Elemental and Chemical Phase Analyses of Ras-Family Ayurvedic Medicinal Products.

Fifteen Ayurvedic medicines of Ras-family (herbo-mineral-metallic preparations) from three reputed manufactures were analysed for elemental quantification and their chemical phase identification using the energy-dispersive (ED) and wavelength-dispersive (WD) X-ray fluorescence (XRF) techniques, and powder X-ray diffraction (XRD) technique, respectively. The low-Z elements C, H, N, S and O constituting a major portion of these medicines were also determined by CHNSO analyser and further used as input for XRF analyses. The elements of concern, Hg, Pb and As, are identified in different medicine products with disquiet concentration values (maximum concentration values range ~ 4-10%) and that too with substantial variations in the products from different manufacturers. These elements are identified mainly in the cinnabar (α-HgS)/metacinnabar (ß-HgS), litharge (PbO) and alacranite (As4S4) phases in different medicines. Keeping in view the high concentration of chemicals of the Hg, Pb and As elements in the Ras-family medicines, it is vitally required to investigate their bioaccessibility and surmise the associated toxicological aspects. It is suggested that the formation of the bioaccessible toxic chemical forms of the Hg, Pb and As elements be avoided during preparation of the mineral ingredients or these soluble chemical forms be removed at suitable stage of the preparation. In view of large variations observed for the Hg, Pb and As based ingredients in the Ras family Ayurvedic medicine products from different manufacturers, adequate quality control mechanisms and production regulations are recommended.