Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"X-ray astronomy"”.
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Active pixel sensors for X-ray astronomy
An active pixel sensor array, APS-1, has been fabricated for the purpose of scientific x-ray detection. This thesis presents the results of testing the device. Alternate design architectures are explored. Recommendations are made for a next-generation sensor. CCDs have been the dominant x-ray …
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High-accuracy foil optics for X-ray astronomy
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2001.
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X-ray astronomy with CCDs : calibration of the advanced CCD imaging spectrometer and observations of rotation-powered pulsars
… the use of charge coupled devices (CCDs) for X-ray astronomy. Part I of this thesis focuses on the calibration of the Advanced CCD Imaging Spectrometer (ACIS), one of the two primary focal plane instruments on the Chandra X-ray Observatory. I begin by presenting a series of measurements made …
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Neutron exposure and neutron flux in Asymptotic Giant Branch stars: a study of neutron capture cross sections of Zr isotopes
… reaction rates, cosmology, cosmochemistry, gamma ray, optical and X-ray astronomy. In general terms, nuclear astrophysics aims to understand the origin of the chemical elements and the energy generation in stars. This work concerns the measurements of the neutron capture cross sections of …
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Designing, constructing, and testing an X-ray polarimeter
X-ray astronomy has been an important field since its birth 50 years ago. However, Xray polarization measurements have been almost non-existent, especially when compared to the amount of polarimetry being performed in the other bands of the spectrum. One method of filtering a specific energy of …
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Design of a near-field coded aperture cameras for high-resolution medical and industrial gamma-ray imaging
… is a technique originally developed for X-ray astronomy, where typical imaging problems are characterized by far-field geometry and an object made of point sources distributed over a mainly dark background. These conditions provide, respectively, the basis of artifact-free and high …
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High-Precision Stress Measurement in Thin Films for X-Ray Mirrors
Future X-ray observatories aim to achieve sub-arcsecond angular resolution with unprecedented sensitivity. Silicon meta-shell optics technology will enable the X-ray astronomy instrumentation community to create such an observatory. The light-weighted silicon mirrors used in meta-shell optics have …
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Ion implantation for figure correction of high-resolution x-ray telescope mirrors
… for future high-resolution, large-aperture x-ray telescopes continues to challenge the x-ray astronomy instrumentation community. Building a large-aperture telescope requires thin, lightweight mirrors; due to the very low stiffness of thin mirrors, these are difficult to fabricate, coat, and …
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Optimizing The Performance Of As-manufactured Grazing Incidence X-ray Telescopes Using Mosaic Detector Arrays
The field of X-ray astronomy is only forty (43) years old, and grazing incidence X-ray telescopes have only been conceived and designed for a little over fifty (50) years. The Wolter Type I design is particularly well suited for stellar astronomical telescopes (very small field-of-view). The first …
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Investigating Interstellar dust in the Milky Way through X-ray scattering and absorption
… studies of the cosmic microwave background. In X-ray astronomy, dust impacts observations by both absorbing and scattering photons. Despite extensive studies at multiple wavelengths, several fundamental aspects of interstellar dust—its composition, size distribution, and large-scale spatial …
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X-ray Studies of the Innermost Regions of Black Hole Accretion
… I present the results of my research on the X-ray spectra of accreting black holes. The content of this thesis can be broadly separated into two parts: Chapter 2-3 for stellar-mass black holes in X-ray binaries (XRBs) and Chapter 4-6 for supermassive black holes in active galactic nuclei (AGN). …
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Studying Accretion Disc Winds with X-ray Spectroscopy
… including supermassive black holes, classical X-ray binaries and Ultraluminous X-ray sources. Outflows form a ubiquitous and important part of the accretion flow, carrying away a considerable fraction of the originally infalling mass. With velocities as high as 30 per cent of the speed of light, …
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X and UV radiation from accreting non-magnetic degenerate dwarfs: A two-fluid treatment of the emission region and the effects of steady nuclear burning
Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-16T16:21:56Z No. of bitstreams: 1 1981_weast.pdf: 3157656 bytes, checksum: c43d64a0b86da434a1750cf61a63b211 (MD5)
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The XMM-Newton/SDSS galaxy cluster survey
… across the electromagnetic spectrum. At X-ray wavelengths, galaxy clusters are simply identified as X-ray luminous, spatially extended, and extragalactic sources. X-ray observations offer the most powerful technique for constructing cluster catalogues. The main advantages of the X-ray …
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A 3-dimensional analysis of the Cassiopeia a supernova remnant.
… Finally, we present a detailed multi-epoch X-ray analysis of Cas A using Chandra X-ray Observatory exposures from 2000, 2002, and 2004. We identify the most recently shocked X-ray ejecta with ionization timescales of #24;1010 cm−3 s, nearly an order of magnitude smaller than previously …
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A Statistical Study of Hard X-Ray Solar Flares
The results of a statistical study of hard x-ray solar flares are presented in this dissertation. Two methods of analysis were used, the Diffusion Entropy (DE) method coupled with an analysis of the data distributions and the Rescaled Range (R/S) Method, sometimes referred to as "Hurst's method". …
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Unveiling fundamental physics with high-resolution X-ray spectroscopy of Active Galactic Nuclei.
… flow onto SMBHs in AGNs as revealed by X-ray observations of AGNs. This is followed with a discussion on the use of X-ray reflection spectroscopy as a probe of the spin of moderately accreting SMBHs, and the use of spin diagnostics to probe the growth of SMBHs over cosmic timescales. …
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Unveiling the X-ray Source Population of the Barred Spiral Galaxy NGC 2336
We present a comprehensive study of the X-ray source population in the nearby spiral galaxy NGC 2336, based on nine Chandra observations spanning a 7-month period. A total of 32 X-ray sources were detected down to a limiting luminosity of ∼ 1.4 × 1038 erg s−1 in the 0.5–7.0 keV (broad) energy band. …
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