Search results for "synchrotron"
showing 10 items of 307 documents
A multiscale X-ray phase-contrast tomography dataset of whole human left lung
2021
ABSTRACTTechnological advancements in X-ray imaging using bright and coherent synchrotron sources now allows to decouple sample size and resolution, while maintaining high sensitivity to the microstructure of soft, partially dehydrated tissues. The recently developed imaging technique, hierarchical phase-contrast tomography, is a comprehensive approach to address the challenge of organ-scale (up to tens of centimeters) soft tissue imaging with resolution and sensitivity down to the cellular level. Using this technique, we imaged ex vivo an entire human left lung at an isotropic voxel size of 25.08 μm along with local zooms down to 6.05 - 6.5 μm and 2.45 - 2.5 μm in voxel size. The high tiss…
Geochemical Interactions of Plutonium with Opalinus Clay Studied by Spatially Resolved Synchrotron Radiation Techniques
2017
Plutonium plays an important role within nuclear waste materials because of its long half-life and high radiotoxicity. The aim of this study was to investigate with high spatial resolution the reactivity of the more oxidized forms of Pu(V,VI) within Opalinus Clay (OPA) rock, a heterogeneous, natural argillaceous rock considered as a potential repository host. A combination of synchrotron based X-ray microprobe and bulk techniques was used to study the spatial distribution and molecular speciation of Pu within OPA after diffusion and sorption processes. Microscopic chemical images revealed a pronounced impact of geochemical heterogeneities concerning the reactivity of the natural barrier mat…
Synthesis and characterization of indium oxide at high pressures
2018
Introducción: La naturaleza es sorprendente pero a la vez limitada. A mi entender, nada tiene más potencial que aplicar el ingenio humano para modificar lo que nos rodea y crear algo completamente nuevo. La Física de la Materia Condensada es un campo que actualmente está ganando importancia en la Física moderna. En virtud de los éxitos logrados en Física de la Materia Condensada se han producido enormes avances en el campo de la electrónica cuántica, de los semiconductores y de la ciencia de materiales, teniendo como resultado numerosas aplicaciones tecnológicas que han cambiado nuestras vidas drásticamente en los últimos 50 años. Una de las ramas de la Física de la Materia Condensada es el…
Using synchrotrons and XFELs for time-resolved X-ray crystallography and solution scattering experiments on biomolecules
2015
International audience; Time-resolved structural information is key to understand the mechanism of biological processes, such as catalysis and signalling. Recent developments in X-ray sources as well as data collection and analysis methods are making routine time-resolved X-ray crystallography and solution scattering experiments a real possibility for structural biologists. Here we review the information that can be obtained from these techniques and discuss the considerations that must be taken into account when designing a time-resolved experiment.
The effects of precipitates on CdZnTe device performance
2005
A high-intensity X-ray beam collimated down to a 10-micrometer spot size, available at Brookhaven's National Synchrotron Light Source (NSLS), was employed to perform X-ray mapping to measure the correlation between microscopic defects (precipitates) and variations in the collected charges in long-drift CdZnTe (CZT) detectors. First, we use X-ray diffraction topography (XDT) measurements at the high-energy beamline and IR microscopy to identify the defects distribution and strains in the bulk of CZT crystals. Then, we perform X-ray raster scans of the CZT detectors to measure their responses with 10-micrometer spatial resolution. The brightness of the source allows for good statistics in ver…
Combination of acoustic levitation with small angle scattering techniques and synchrotron radiation circular dichroism. Application to the study of p…
2016
Abstract Background The acoustic levitation technique is a useful sample handling method for small solid and liquids samples, suspended in air by means of an ultrasonic field. This method was previously used at synchrotron sources for studying pharmaceutical liquids and protein solutions using x-ray diffraction and small angle x-ray scattering (SAXS). Methods In this work we combined for the first time this containerless method with small angle neutron scattering (SANS) and synchrotron radiation circular dichroism (SRCD) to study the structural behavior of proteins in solutions during the water evaporation. SANS results are also compared with SAXS experiments. Results The aggregation behavi…
Alanine films for EPR dosimetry of low-energy (1–30 keV) X-ray photons
2019
Abstract L- α -alanine has aroused considerable interest for use in radiation EPR dosimetry and has been formally accepted as a secondary standard for high-dose (kGy) and transfer dosimetry of high-energy photons and electrons. In this work, we extended the investigation of the energy response of alanine EPR films in the low energy range for X-photons (1–30 keV). Electron Paramagnetic Resonance (EPR) measurements were performed on Kodak BioMax alanine films exposed to low-energy X-rays from a Cu-, W- and Mo-targets tube operating at voltages up to 30 kV. Films were chosen because of the low penetration of the soft X-rays used. The response of alanine to low-energy X-rays was characterized e…
Synchrotron radiation studies on luminescence of Eu2+-doped LaCl3 microcrystals embedded in a NaCl matrix
2012
Abstract LaCl3:Eu2+ microcrystals dispersed in the NaCl matrix have been obtained in the NaCl–LaCl3(1 mol.%)–EuCl3(0.1 mol.%) crystalline system. The low-temperature luminescent properties of these microcrystals have been studied upon the VUV and UV excitation by the synchrotron radiation. The spectroscopic parameters as well as decay time constants of Eu2+-doped LaCl3 host have been established. The excitation mechanism of divalent europium centers through energy transfer and reabsorption is discussed.
A pulsed high-voltage decelerator system to deliver low-energy antiprotons
2021
International audience; The GBAR (Gravitational Behavior of Antihydrogen at Rest) experiment at CERN requires efficient deceleration of 100 keV antiprotons provided by the new ELENA synchrotron ring to synthesize antihydrogen. This is accomplished using electrostatic deceleration optics and a drift tube that is designed to switch from -99 kV to ground when the antiproton bunch is inside – essentially a charged particle “elevator” – producing a 1 keV pulse. We describe the simulation, design, construction and successful testing of the decelerator device at -92 kV on-line with antiprotons from ELENA.
A Time Projection Chamber with GEM-Based Readout
2016
For the International Large Detector concept at the planned International Linear Collider, the use of time projection chambers (TPC) with micro-pattern gas detector readout as the main tracking detector is investigated. In this paper, results from a prototype TPC, placed in a 1 T solenoidal field and read out with three independent GEM-based readout modules, are reported. The TPC was exposed to a 6 GeV electron beam at the DESY II synchrotron. The efficiency for reconstructing hits, the measurement of the drift velocity, the space point resolution and the control of field inhomogeneities are presented.