Sökning: "radiation generation"

Visar resultat 1 - 5 av 163 avhandlingar innehållade orden radiation generation.

  1. 1. Photonic terahertz-wave generation, radiation and quasioptical integration

    Författare :Biddut Kumar Banik; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; semiconductor device modelling; semiconductor diodes; III-V semiconductors; Catadioptric lens; imaging; dipole antennas; slot antennas; lens antennas; semiconductor heterojunctions; dielectric loaded antennas; optical mixers; photomixers; near-field imaging; computer aided engineering; indium compounds; millimetre wave imaging; near-field optics; submillimeter wave generation; photodiodes; terahertz sources; millimetre wave generation; submillimetre wave integrated circuits; microwave imaging; uni-travelling-carrier photodiodes;

    Sammanfattning : This thesis deals with the uni-travelling-carrier photodiode (UTC-PD) based photonic generation of terahertz waves, antenna designs for the terahertz radiation and a novelcatadioptric lens for quasioptical integration.The ongoing and accomplished research work on the UTC-PD, its limitations and optimisation scopes for attaining higher bandwidth and higher output power have been discussed. LÄS MER

  2. 2. Inductive Pulse Generation

    Författare :Adam Lindblom; Hans Bernhoff; Jan Isberg; Anders Larsson; Owen Farish; Uppsala universitet; []
    Nyckelord :Technology; Pulsed Power; Inductive Pulse Generator; High Voltage; Semicon; XLPE; TEKNIKVETENSKAP; TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : Pulsed power generators are a key component in compact systems for generation of high-power microwaves (HPM). HPM generation by virtual cathode devices such as Vircators put high demands on the source. The rise time and the pulse length of the source voltage are two key issues in the generation of HPM radiation. LÄS MER

  3. 3. Intense laser-plasma interactions

    Författare :Joel Magnusson; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; radiation reaction; radiation generation; particle-in-cell; plasma; pair production cascades; ion acceleration; laser;

    Sammanfattning : In the interaction of ultra-intense laser fields with matter, the target is rapidly ionized and a plasma is formed. The ability of a plasma to sustain acceleration gradients, orders of magnitude larger than achievable with conventional accelerators, has led to a great interest in laser-driven plasma-based particle and radiation sources, with applications in materials science, biology and medicine. LÄS MER

  4. 4. Utilizing Problem Structure in Optimization of Radiation Therapy

    Författare :Fredrik Carlsson; Anders Forsgren; Edwin Romeijn; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Optimization; intensity-modulated radiation therapy; conjugate-gradient method; step-and-shoot delivery; column generation; quasi-Newton method; regularization; sequential quadratic programming; Optimization; systems theory; Optimeringslära; systemteori;

    Sammanfattning : In this thesis, optimization approaches for intensity-modulated radiation therapy are developed and evaluated with focus on numerical efficiency and treatment delivery aspects. The first two papers deal with strategies for solving fluence map optimization problems efficiently while avoiding solutions with jagged fluence profiles. LÄS MER

  5. 5. Ethical Aspects of Radiation Risk Management

    Författare :Per Wikman-Svahn; John Cantwell; Carl F. Cranor; KTH; []
    Nyckelord :HUMANITIES; HUMANIORA; HUMANITIES; HUMANIORA; radiation protection; radiological protection; nuclear power; nuclear energy; social issues; ethical issues; ethics; risk; uncertainty; value judgments; precautionary principle; distributive issues; justice; limits; prioritarianism; responsibility; egalitarianism; black swan; black elephant; risk management;

    Sammanfattning : This thesis is based on the assumption that the intersection of moral philosophy and practical risk management is a rewarding area to study. In particular, the thesis assumes that concepts, ideas, and methods that are used in moral philosophy can be of great benefit for risk analysis, but also that practices in risk regulation provide a useful testing ground for moral philosophical theories. LÄS MER