Search results for "X ray"
showing 10 items of 173 documents
X-Ray Spectral Variability of 3C273
1985
3C273 has been monitored by EXOSAT over the period December 1983 to June 1984 in 4 observations. In the December observation the flux was high and the spectrum showed a power law index of 1.5 changing to 0.9 at~8 keV. In subsequent observations the flux dropped to~40% of its original value and the hard tail disappeared. In the last observation the LE flux increased by a factor of 2 with no accompanying ME flux increase.
The Palermo XACT facility: a new 35 m long soft x-ray beam-line for the development and calibration of next-generation x-ray observatories
2006
The X-ray Astronomy Calibration and Testing (XACT) facility of the Instituto Nazionale di Astrofisica (INAF) at Osservatorio Astronomico di Palermo has recently undergone a major upgrade with the design and construction of a 35 meter long vacuum beam-line operating in the soft X-rays (0.1-20 keV) and the addition of new hardware to meet the requirements for testing and calibration of next generation X-ray missions. We report on the present configuration of the facility and briefly survey the range of its applications.
Development of a TES based Cryo-Anticoincidence for a large array of microcalorimeters
2009
The employment of large arrays of microcalorimeters in space missions (IXO, EDGE/XENIA)[1][2][3], requires the presence of an anticoincidence detector to remove the background due to the particles, with a rejection efficiency at least equal to Suzaku (98%) [1]. A new concept of anticoincidence is under development to match the very tight thermal requirements and to simplify the design of the electronic chain. The idea is to produce a Cryo-AntiCoincidence (Cryo-AC) based on a silicon absorber and read by a TES (Transition-Edge Sensor). This configuration would ensure very good performances in terms of efficiency, time response and signal to noise ratio. We present the results of estimations,…
High performance 3D CZT spectro-imager for BNCT-SPECT: preliminary characterization
2018
The National Institute of Nuclear Physics (INFN) is supporting the 3CaTS project with the aim of developing a new Single Photon Emission Computed Tomography (SPECT) system for real time 10 B therapeutic dose monitoring in the binary experimental hadron therapy called Boron Neutron Capture Therapy (BNCT). BNCT is a highly selective tumour treatment based on the neutron capture reaction 10 B(n,α) 7 Li. The secondary particles have a high LET with ranges in tissues of the order of 10 μm (thus less than the mean cell diameter of few tens μm). Targeting the 10 B delivery towards cancer, the released energy lethally damages only the malignant cells sparing the normal tissues, thus enabling a cell…
The Influence of Intramolecular Coordination and Ring Strain on the Polymerization Potential of Cyclic Stannasiloxanes
2008
Size dependent light absorption modulation and enhanced carrier transport in germanium quantum dots devices
2015
Quantum confinement in closely packed arrays of Ge quantum dots (QDs) was studied for energy applications. In this work, we report an efficient tuning mechanism of the light harvesting and detection of Ge QDs. Thin films of SiGeO alloys, produced by rf-magnetron sputtering, were annealed at 600 degrees C in N-2 to induce precipitation of small amorphous Ge QDs into the oxide matrix. Varying the Ge content, the QD size was tailored between 2 and 4 nm, as measured by high resolution transmission electron microscopy. X-ray photoelectron spectroscopy (XPS) measurements indicate the formation of pure SiO2, as well as the presence of a sub-stoichiometric Ge oxide shell at the QD interface. Light …
Influencia de la tomografía computarizada abdominal en la estadificación del cáncer de pulmón
2002
Objetivos Analizar la influencia de la exploracion sistematica del abdomen superior mediante TC convencional en la estadificacion de los pacientes diagnosticados de carcinoma broncopulmonar, para la deteccion de las metastasis hepaticas o adrenales. Como objetivo secundario, decribir las caracteristicas de un amplio grupo de pacientes de nuestro medio Material y Metodos Estudio retrospectivo de 387 pacientes (367 varones y 20 mujeres; edad media [± DE] 62,3 ± 10,4 anos, limites, 34–90 anos) diagnosticados de cancer de pulmon (203 carcinoma epidermoide, 75 adenocarcinoma, 15 carcinoma de celulas grandes, 68 carcinoma microcitico y 25 tumores mixtos). La exploracion TC se extendio desde el es…
The lung in inflammatory bowel disease.
2000
Lifesaving Stenting of Pulmonary Arteries Critically Narrowed by Mediastinal Lymphoma
2019
Publisher Correction: X-Ray Nanotomography of Individual Pulp Fibre Bonds Reveals the Effect of Wall Thickness on Contact Area
2020
Fibre bonds play an essential role in various properties of paper. Much research has focused on their strength, but the determination of the actual contact area also provides a challenge. Many of the research methods rely on optical tools, which are restricted by the wavelength of light that is utilised. Novel X-ray computed tomography devices utilise X-rays in studying the inner structure of materials, and surpass the optical methods in terms of resolution, allowing detection of even smaller details and variations in distance between the fibres in the bond intersection area. X-ray nanotomography was used to image 26 individual cellulose fibre bonds made of springwood and summerwood fibres …