Analysis of X-ray whispering gallery waves propagating along liquid meniscuses

X-ray diffraction and fluorescence of whispering galleries (WGs) which propagate along meniscuses of deionized water or silicahydrosols enriched by CsOH have been analyzed for the first time. The measurements have been performed using the diffractometer with a moving tube-detector system. The X-ray beam rotation angle reached a maximum value of 4° on a silica hydrosol sample. The WG mode propagating near the surface of a concave meniscus as well as the fluorescence intensity have been found from a solution of the respective Helmholtz equations. For analysis of intensities of the X-ray scattering and fluorescence we have used a two-layer model of the liquid with the upper non-uniform corrugated layer in which the concentration of levitating Cs+ ions near the surface has a maximum derived from the experiment in the hydrosol depth of ~ 15 nm for SiO2particle sizes of ~ 5...7 nm. In order to determine the fluorescence intensity we have used the approach based on a method of fundamental parameters using the reciprocity theorem

Defining background DNA levels found on the skin of children aged 0-5 years

There are currently no data available regarding the normal levels of DNA found on the skin of children engaging in routine day to day activities to assist with the forensic interpretation of DNA profiles generated from skin surface swabs. To address this deficit, skin surface swab samples were collected from 12 face/neck sites and 20 body sites on 50 children less than 5 years old. After exclusion of spoilt samples, 60 sets of swabs from 47 children (30 face/neck, 30 body) comprising of 944 individual samples were analysed. The number of alleles observed which could have originated from the child and the number which must have come from another source (non-child) were analysed. The following variables were evaluated: age, kissing, feeding and washing practices, number of contacts and application of cream. Overall, extremely small amounts of non-child DNA were retrieved from skin swabs. Child only (46.3 %) or no DNA at all (18.6 %) was observed for 64.9 % of all swabbed samples. Low levels of non-child DNA (1-5 alleles) were observed on 31.6 % of all swabs tested with only 3.4 % of swabs showing six or more alleles. A great deal of variation between children and between sites in the levels of both child DNA and non-child DNA was observed. A multilevel model, taking account of clustering within children, showed that there was a strong direct association between the amounts of child and non-child DNA observed. There was no relationship between the amount of DNA recovered and the demographic and biographic variables analysed. These background data have the potential to assist the analysis of DNA from the skin of children during criminal investigation

Fabrication and characterization of high efficiency multilayer-coated blazed gratings for EUV range

Multilayer coated blazed gratings with high groove density are the most promising candidate for high resolution EUV and soft x-ray spectroscopy. They combine the ability of blazed gratings to concentrate almost all diffraction energy in a desired high diffraction order with high reflectance of EUV and soft x-ray multilayers. The gratings however have to be of superior quality in order to realize their potential. Thus, the grating fabrication process should provide a perfect triangle groove profile and extremely smooth surface of the blazed facets. Here we report on recent progress in fabrication and characterization of the gratings designed for EUV applications. The gratings having groove density from 5000 to 10000 lines/mm were fabricated with scanning beam interference lithography or electron beam lithography followed by wet anisotropic etch of silicon wafers and multilayer deposition. The groove surface morphology was characterized with AFM and SEM, and evolution of the structure of the multilayer stack in the course of multilayer deposition onto the corrugated surface of the blazed grating was studied with TEM (Fig. 1). The grating diffraction efficiency measurements were performed at the ALS beam line 6.3.2. The grating coated with the Mo/Si multilayer composed of 30 bi-layers demonstrated diffraction efficiency more than 37percent in the 3rd diffraction order (Fig. 2). An impact of groove profile imperfections and perturbations of the multilayer stack was also investigated via efficiency simulations with PCGrate 6.1 code. The results of the study show good prospects to extend the technology towards soft x-rays