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Although the concept, first demonstration, and potential applications of X-ray transmission mirrors (XTMs) were initially described over 30 years ago, only a few implementations exist in the literature. This is attributed to the unsolved challenge of a thick frame supporting a thin, reflecting membrane which does not itself block the transmitted beam. Here, we introduce a novel approach to solve this problem by employing silicon microfabrication. A robust XTM frame has been fabricated by using a novel two-step etch process, which secures the thin-film membrane without blocking the transmitted beam. Specifically, we have fabricated delicate XTM optics with 90% yield, which consist of 280-nm-thick low-stress silicon nitride membrane windows that are 1.5 mm wide and 125 mm long on silicon substrates. The XTM optics have been demonstrated to be a more efficient high-pass X-ray filter; for example, when configured for 40% transmission of 11.3 keV photons, we measure the reduction of 8.4 keV photons by a factor of 56.
For exploring the prospect of higher-k dielectric phase engineering on a high
mobility substrate, films of Hf1-xZrxO2 with
varying x-values (0 ≤ x ≤ 1) were deposited on
Al2O3 passivated Ge substrates using atomic layer
deposition (ALD) with a cyclic deposit-anneal-deposit-anneal (DADA) scheme. The
evolution of monoclinic to higher-k tetragonal structure with increasing
ZrO2 concentration was probed by grazing incident x-ray
diffraction and partial reciprocal space maps using the highly brilliant
synchrotron x-ray source at the Cornell High Energy Synchrotron Source (CHESS).
A primarily amorphous/nano-crystalline matrix of the asdeposited films changed
to randomly aligned grains of nanocrystalline MO2 (M=Hf, Zr)
after post deposition annealing at 800 °C for 200 seconds. In contrast,
the DADA films annealed for same thermal budget showed high degree of preferred
orientation along certain crystallographic directions. With increasing
ZrO2 content, the structure of the films changed from a monoclinic to
a tetragonal phase. A lower amount of ZrO2 (x = 0.33) was
required for stabilizing the tetragonal phase in films grown on
Al2O3 passivated Ge substrate as compared to similar
films grown on a Si substrate via the same DADA process (x ≥
The 17th c. Flemish painting on panel, The Armorer's Shop, has long been attributed to David Teniers the Younger (1610-1690). The painting depicts an opulent pile of parade armor at the bottom left foreground, a seated armorer at the bottom right foreground, and a forge surrounded by workers in the middle ground. The Teniers attribution is derived from his signature at the bottom right as well as figural groups and other visual elements that are commonly associated with him and executed in his style. During dendrochronological examination of the painting, a portion of the oak plank comprising the overall structure was found to have been carved out so that a smaller plank (containing the parade armor) could be inserted into the resulting depression. This unusual construction, combined with the identification of several paintings by Jan Brueghel the Younger (1601-1678) depicting the same parade armor, raised questions about the attribution and chronology of construction of the painting. Art historical research suggests that the smaller plank with the armor was painted by Brueghel and that the remainder of the panel with the workers and forge was painted by his brother-in-law Teniers. While Brueghel writes of collaborating with Teniers in his journal, this appears to be the only identified collaboration of the two artists. Conventional microanalysis methods did not resolve the painting's construction chronology. However, confocal x-ray fluorescence microscopy (CXRF) revealed the composition and location of buried paint layers at the panel interfaces by combining depth scans at a number of adjacent lateral positions to produce virtual cross-sections over 20 mm in length. The relationship of the paint layers at the panel interfaces provided evidence for the armor panel having been painted separately and prior to the rest of the composition. This data, along with dendrochronological and IRR data, provided a chronology of construction for the painting that provided additional evidence for a Brueghel attribution. An overview of the CXRF technique will be provided along with a discussion of how CXRF data relates to data collected using SEM-EDS, FTIR, Raman, conventional XRF, x-radiography, IRR, and dendrochronology.
Homoepitaxial SrTiO3 thin films were grown on SrTiO3 (001) using Pulsed Laser Deposition (PLD). The deposition process was monitored in-situ, via both x-ray reflectivity and surface diffuse x-ray scattering measurements in the G3 experimental station at the Cornell High Energy Synchrotron Source (CHESS). Using a CCD detector in 1D, or streak-camera, mode with approximately 0.3-second time resolution, data were collected during growths performed at two substrate temperatures: 695°C and 1000°C. While the specular reflectivity oscillations for the two growths are very similar, the diffuse scattering clearly shows a distinct change in the peak position. Using Atomic Force Microscopy (AFM), we illustrate how the peak position for the diffuse lobes of scattered intensity is directly related to the distribution of single unit cell high islands on the growing surface. Thus, the peak shift of the diffuse scattering indicates an order of magnitude change in the island density.
This is a copy of the slides presented at the meeting but not formally written up for the volume.
Homoepitaxial SrTiO3 thin films were grown on SrTiO3 (001) via Pulsed Laser Deposition. The growth was monitored in real-time by in situ X-ray reflectivity measurements at the anti-Bragg point of the (00L) Crystal Truncation Rod. Due to the need for a large X-ray intensity to monitor the anti-Bragg position, these experiments were performed at the Cornell High Energy Synchrotron Source (CHESS). We investigated the role of laser repetition rate and substrate temperature for films deposited at an O2 background pressure of 10-6 Torr. We observe a transition in growth mode from layer-by-layer to step-flow with increasing temperature while keeping laser repetition rate constant. We observed a similar transition in the growth mode when the substrate temperature is held constant and the laser repetition rate is decreased. The surface miscut is also observed to play a similar role. We show that this transition can be described in terms of the deposition rate, diffusion length, and step spacing.
A confocal x-ray fluorescence microscope was built at the Cornell High Energy Synchrotron Source (CHESS) to determine the composition of buried paint layers that range from 10–80 μm thick in paintings. The microscope consists of a borosilicate monocapillary optic to focus the incident beam and a borosilicate polycapillary lens to collect the fluorescent x-rays. The overlap of the two focal regions is several tens of microns in extent, and defines the active, or confocal, volume of the microscope. The capabilities of the technique were tested using acrylic paint films with distinct layers brushed onto glass slides and a twentieth century oil painting on canvas. The position and thickness of individual layers were extracted from their fluorescence profiles by fitting to a simple, semi-empirical model.
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