Sökning: "focal spot"

Visar resultat 1 - 5 av 8 uppsatser innehållade orden focal spot.

1. 1. Focal Spot Optimization Using Spatial Light Modulation and a Phase Retrieval Algorithm

   Master-uppsats, Lunds universitet/Atomfysik; Lunds universitet/Fysiska institutionen

   Författare :Robert Petersen; [2023]
   Nyckelord :Spatial Light Modulation; Phase Retrieval Algorithm; Focal Spot Optimization; Adaptive Optics; Wavefront Sensing; Lasers; Physics and Astronomy; Technology and Engineering;

   Sammanfattning : Aberrations to the wavefront of a laser beam reduce the quality of the focal spot and are generally undesired. This project is aimed at determining the aberrations of laser beams by using a phase retrieval algorithm and to show that it is possible to correct the aberrations with a spatial light modulator to optimize the focal spot. LÄS MER

3. 2. Simulating and Testing the Polarimetric Response of the X-ray Polarimetry Telescope XL-Calibur

   Master-uppsats, KTH/Fysik

   Författare :Filip af Malmborg; [2022]
   Nyckelord :Astroparticle Physics; Astrophysics; Detector Physics; Simulation; Theoretical Physics; Engineering Physics; Astropartikelfysik; Astropartikelfysik; Detektorfysik; Simulering; Teoretisk Fysik; Teknisk Fysik;

   Sammanfattning : X-ray polarimetry, the study of the polarisation of X-ray light, is a powerful and rapidly developing tool for astrophysics, which promises to help answer outstanding questions about the physics of extreme objects such as pulsars, X-ray binaries and active galactic nuclei. The balloon-borne telescope XL-Calibur will be the first instrument to study the polarisation of hard X-rays (with energies between 10 and 100 keV) in detail, correlating with the soft X-ray observations of IXPE to provide further tests of polarisation-dependent x-ray emission models in extreme objects. LÄS MER

4. 3. mm Wave Near Field Spot Focus Technique in Free Space Dielectric  Properties Evaluation Method

   Master-uppsats, KTH/Skolan för elektroteknik och datavetenskap (EECS)

   Författare :Yanhan Liu; [2021]
   Nyckelord :Permittivity; near-field-focused NFF antenna; genetic algorithm; Permittivitet; närfältsfokuserad antenn; genetisk algoritm.;

   Sammanfattning : Radomes were invented to protect sensitive antenna systems from the disturbing environment. Estimation of their permittivity is a vital step for their design. This project studies the free- space method to measure the permittivity of radome materials. LÄS MER

5. 4. Simulation of Anti-Compton Shield Augmentation to the Lundium Decay Station Using Geant4

   Kandidat-uppsats, Lunds universitet/Kärnfysik; Lunds universitet/Fysiska institutionen

   Författare :Daesung Cho; [2019]
   Nyckelord :Lundium; Geant4; Anti-Compton shield; gamma spectroscopy; Physics and Astronomy;

   Sammanfattning : The Lundium decay station improves on the existing TASISpec spectrometer used to investigate the nuclear structure of superheavy nuclei by photon- and charged particle-spectroscopy. This thesis aims to explore the potential benefits of the future Lundium station with the augmentation of anti-Compton shields com- posed by a set of BGO scintillator bars. LÄS MER

7. 5. Validation of simulation tool for C-arm X-ray systems : Source and scatter model

   Master-uppsats, KTH/Skolan för teknik och hälsa (STH)

   Författare :Martina Jurcova; [2016]
   Nyckelord :Simulation; C-arm system; X-ray imaging; focal spot; scattering; image sharpness;

   Sammanfattning : Continuous improvement of image quality is one of the priorities in medical imaging. Therefore, development of a simulation tool allowing to generate realistic images would be of great value to understand better the impact of the components on the image quality metrics and to choose imaging set-ups or new design features to optimize output of existing systems and to prototype new ones and to formalize the link between objective and subjective image quality metrics. LÄS MER