86,777 research outputs found
Grazing exit versus grazing incidence geometry for x-ray absorption near edge structure analysis of arsenic traces
No full textIn the presented study the grazing exit x-ray fluorescence was tested for its applicability to x-ray
absorption near edge structure analysis of arsenic in droplet samples. The experimental results have
been compared to the findings of former analyses of the same samples using a grazing incidence
GI setup to compare the performance of both geometries. Furthermore, the investigations were
accomplished to gain a better understanding of the so called self-absorption effect, which was
observed and investigated in previous studies using a GI geometry. It was suggested that a normal
incidence-grazing-exit geometry would not suffer from self-absorption effects in x-ray absorption
fine structure XAFS analysis due to the minimized path length of the incident beam through the
sample. The results proved this assumption and in turn confirmed the occurrence of the
self-absorption effect for GI geometry. Due to its lower sensitivity it is difficult to apply the GE
geometry to XAFS analysis of trace amounts few nanograms of samples but the technique is well
suited for the analysis of small amounts of concentrated sample
Time-dependent observations of arsenic ultra shallow junctions formed by AsH3 Plasma Immersion Ion Implantation and Deposition in Silicon
No full textPlasma immersion ion implantation and deposition (PIIID) is an attractive technique for creating ultra-shallow dopant distributions with extremely high levels of active dopant concentration, with the added value of conformal doping. The latter is crucial for the realization of tridimensional transistor structures like fin-FETs or similar. While many reports about boron PIII doping of silicon can be found in literature, n-type doping reports are sparse, particularly concerning arsenic. In this work, samples obtained by
implanting high fluences (~1E15 at./cm2) of AsH3+ on (100) Si by ultra low energy (<2 kV) PIIID (AsH3/ H2 plasma atmosphere) were examined using SEM, SIMS, XPS, ToF-SIMS, INAA, TEM, Raman spectroscopy, and EXAFS. ‘As-implanted’ arsenic distributions were found to be confined within <10 nm depth with a < 2 nm/decade profile abruptness corresponding to the SIMS depth resolution (300 eV/ 45° Cs+ beam). Additionally, two phenomena were observed at very high arsenic surface concentrations: 1) the spontaneous formation of arsenolite micro-crystals at the samples surface when exposed to atmosphere [1]; 2) a rapid growth of the native Si oxide reaching an equilibrium value of several nanometers after a few weeks of air exposure. We will report recent results of further investigations of these effects, carried out in order to identify their root cause and their
impact on successive annealing. [1] F. Meirer, et al., Applied Physics Letters, 101, 232107 (2012
Synchrotron radiation induced TXRF- a critical review
No full textThe use of synchrotron radiation (SR) as an excitation source for total reflection X-ray fluorescence
analysis (TXRF) offers several advantages over X-ray tube excitation. Detection limits in the fg range
can be achieved with efficient excitation for low Z as well as high Z elements due to the features of
synchrotron radiation and in particular the high brilliance in a wide spectral range and the linear
polarization in the orbital plane. SR-TXRF is especially interesting for samples where only small
sample masses are available. Lowest detection limits are typically achieved using multilayer
monochromators since they exhibit a bandwidth of about 0.01 DE/E. Monochromators with smaller
bandwidth like perfect crystals, reduce the intensity, but allow X-ray absorption spectroscopy (XAS)
measurements in fluorescence mode for speciation and chemical characterisation at trace levels.
SR-TXRF is performed at various synchrotron radiation facilities. An historical overview is presented
and recent setups and applications as well as some critical aspects are reviewed
Maris,JJE_SciRep_2022_12_9595_open_data
No full textRaw and processed simulation data for Maris, J. J. E., Rabouw, F. T., Weckhuysen, B. M. & Meirer, F. Classification-based motion analysis of single-molecule trajectories using DiffusionLab. Sci. Rep. 12, 9595 (2022).
Details about files can be found in the README.txt files.
Additional data is available via the group Inorganic Chemistry and Catalysis, [email protected], contact person Florian Meirer
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
JGIXA — A software package for the calculation and fitting of grazing incidence X-ray fluorescence and X-ray reflectivity data for the characterization of nanometer-layers and ultra-shallow-implants
No full textAbstractGrazing incidence XRF (GIXRF) is a very surface sensitive, nondestructive analytical tool making use of the phenomenon of total external reflection of X-rays on smooth polished surfaces. In recent years the method experienced a revival, being a powerful tool for process analysis and control in the fabrication of semiconductor based devices. Due to the downscaling of the process size for semiconductor devices, junction depths as well as layer thicknesses are reduced to a few nanometers, i.e. the length scale where GIXRF is highly sensitive. GIXRF measures the X-ray fluorescence induced by an X-ray beam incident under varying grazing angles and results in angle dependent intensity curves. These curves are correlated to the layer thickness, depth distribution and mass density of the elements in the sample. But the evaluation of these measurements is ambiguous with regard to the exact distribution function for the implants as well as for the thickness and density of nanometer-thin layers. In order to overcome this ambiguity, GIXRF can be combined with X-ray reflectometry (XRR). This is straightforward, as both techniques use similar measurement procedures and the same fundamental physical principles can be used for a combined data evaluation strategy. Such a combined analysis removes ambiguities in the determined physical properties of the studied sample and, being a correlative spectroscopic method, also significantly reduces experimental uncertainties of the individual techniques.In this paper we report our approach to a correlative data analysis, based on a concurrent calculation and fitting of simultaneously recorded GIXRF and XRR data. Based on this approach we developed JGIXA (Java Grazing Incidence X-ray Analysis), a multi-platform software package equipped with a user-friendly graphic user interface (GUI) and offering various optimization algorithms. Software and data evaluation approach were benchmarked by characterizing metal and metal oxide layers on Silicon as well as Arsenic implants in Silicon. The results of the different optimization algorithms have been compared to test the convergence of the algorithms. Finally, simulations for Iron nanoparticles on bulk Silicon and on a W/C multilayer are presented, using the assumption of an unaltered X-ray Standing Wave above the surface
[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
Also By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation
No full textThe desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
John F. Kennedy telegram to Roosevelt
No full textJersey Homesteads (later the Borough of Roosevelt) was established in the 1930s as an agro-industrial cooperative community. It was established specifically for urban Jewish garment workers, many of whom had emigrated from Europe. President John F. Kennedy sent a telegram to the citizens of Roosevelt, New Jersey, apologizing for not being able to attend the memorial dedication in honor of former President Franklin Delano Roosevelt. (Jersey Homesteads became Roosevelt in 1945 in honor of the president.) President Kennedy expressed his gratitude to the people of Roosevelt for constructing the memorial, and commented that it will serve as a constant reminder of Roosevelt's good works
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