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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Achromatische Röntgenlinsen

Umbach, Marion January 2009 (has links)
Zugl.: Karlsruhe, Univ., Diss., 2009 / Hergestellt on demand. - Zusätzliches Online-Angebot unter http://uvka.ubka.uni-karlsruhe.de/shop/isbn/978-3-86644-419-5
2

Application and System Design of Elastomer Based Optofluidic Lenses

Savidis, Nickolaos January 2012 (has links)
Adaptive optic technology has revolutionized real time correction of wavefront aberrations. Optofluidic based applied optic devices have offered an opportunity to produce flexible refractive lenses in the correction of wavefronts. Fluidic lenses have superiority relative to their solid lens counterparts in their capabilities of producing tunable optical systems, that when synchronized, can produce real time variable systems with no moving parts. We have developed optofluidic fluidic lenses for applications of applied optical devices, as well as ophthalmic optic devices. The first half of this dissertation discusses the production of fluidic lenses as optical devices. In addition, the design and testing of various fluidic systems made with these components are evaluated. We begin with the creation of spherical or defocus singlet fluidic lenses. We then produced zoom optical systems with no moving parts by synchronizing combinations of these fluidic spherical lenses. The variable power zoom system incorporates two singlet fluidic lenses that are synchronized. The coupled device has no moving parts and has produced a magnification range of 0.1 x to 10 x or a 20 x magnification range. The chapter after fluidic zoom technology focuses on producing achromatic lens designs. We offer an analysis of a hybrid diffractive and refractive achromat that offers discrete achromatized variable focal lengths. In addition, we offer a design of a fully optofluidic based achromatic lens. By synchronizing the two membrane surfaces of the fluidic achromat we develop a design for a fluidic achromatic lens.The second half of this dissertation discusses the production of optofluidic technology in ophthalmic applications. We begin with an introduction to an optofluidic phoropter system. A fluidic phoropter is designed through the combination of a defocus lens with two cylindrical fluidic lenses that are orientated 45° relative to each other. Here we discuss the designs of the fluidic cylindrical lens coupled with a previously discussed defocus singlet lens. We then couple this optofluidic phoropter with relay optics and Shack-Hartmann wavefront sensing technology to produce an auto-phoropter device. The auto-phoropter system combines a refractometer designed Shack-Hartmann wavefront sensor with the compact refractive fluidic lens phoropter. This combination allows for the identification and control of ophthalmic cylinder, cylinder axis, as well as refractive error. The closed loop system of the fluidic phoropter with refractometer enables for the creation of our see-through auto-phoropter system. The design and testing of several generations of transmissive see-through auto-phoropter devices are presented in this section.
3

Transverse Resonance Island Buckets in Advanced Light Sources

Arlandoo, Michael Etienne 18 October 2024 (has links)
Transverse Resonance Island Buckets (TRIBs) ist eine spezielle Einstellung der strahlführenden Magnetoptik eines Speicherrings nahe einer nichtlinearen Resonanz, die einen zweiten vom Hauptorbit gut getrennten und stabilien Orbit erzeugt. Dieser Inselorbit ist verknüpft mit zusätzlichen Potentialtöpfen im transversalen Phasenraum, in denen ebenfalls Elektronen gespeichert werden können. Wird der Speicherring als Synchrotronstrahlungsquelle genutzt, so können den Experimentatoren durch die zwei stabilien Orbits zwei unterschiedliche Lichtquellen mit z.B. unterschiedlichen Pulswiederholungsraten angeboten werden. Diese Dissertation untersucht, ob man die TRIBs Einstellung mit der deutlich komplizierteren und nichtlinear anspruchsvolleren Multi-Bend-Achromat (MBA) Magnetoptik einer vierten Generation Synchrotronstrahlungsquelle zusammen bringen kann. Ein resonanter Hamiltonian in der Nähe einer horizontalen Resonanzen dritter Ordnung, die von Sextupolen getrieben wird, abgeleitet. Dieser Hamiltonian enthält drei Parameter, die den TRIBs-Phasenraum vollständig definieren, nämlich den Abstand des Arbeitspunktes zur Resonanz, die Resonanzstärke und den "detuning-Parameter", der beschreibt wie die Resonanz auf Teilchen mit unterschiedlichen Amplituden wirkt. Durch die analytische Betrachtung der Resonanzstärke in Hinblick auf die entscheidenden Größen der Magnetoptik, d.h. die Twiss-Optikfunktionen und die Sextupolstärken zeigt sich ein unterschiedliches TRIBs verhalten für systematischen Resonanzen und nicht-systematische Resonanzen. Bei nicht-systematischen Resonanzen muss die Periodizität der Magentoptik gestört werden um TRIBs zu erzeugen. Bei systematischen Resonanzen, muss der Arbeitspunkt sowohl des Rings als auch seiner sich wiederholenden periodischen Einheitszelle die Resonanzbedingung dritter Ordnung erfüllen um TRIBs zu erzeugen. / Transverse resonance island buckets (TRIBs) is a special accelerator optics mode where the storage ring is tuned close to a nonlinear resonance and this results in the production of a secondary stable orbit, well separated from the main one. This orbit corresponds to islands in transverse phase space and it can be filled with bunches independently from the main orbit to some extent. This thesis investigates the possibility of implementing the TRIBs mode in the multi-bend achromat (MBA) lattice candidates of BESSY III right from the beginning when strong nonlinearities due to sextupole magnets are present. A resonant Hamiltonian is derived using the perturbative techniques of nonlinear dynamics, valid close to third-order horizontal resonances. This Hamiltonian contains three parameters that fully determine the structure of the phase space with islands namely the distance from the resonance in tune space, the resonance strength, and the detuning, a parameter that gives the rate at which particles with different amplitudes hit the resonance. By calculating the resonance strength analytically in terms of the lattice quantities such as the Twiss functions and the sextupole strengths, two types of resonances are revealed in a transparent manner and it is shown that close to these third-order resonances, islands can be established. The first one is the random resonance where the periodicity of the lattice needs to be broken to have islands. The need for a periodicity breaking is proved explicitly. The second type is the systematic resonance where the tunes of both the ring and its superperiod (repeating unit) need to satisfy a third-order resonance condition. These two types of resonances are studied and compared in detail and the stability of the two BESSY III lattice candidates with respect to TRIBs is discussed.

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