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Found 5 essays matching the above criteria.

  1. 1. Detective Quantum Efficiency in the Image Domain

    University essay from KTH/Fysik

    Author : Per Lundhammar; [2022]
    Keywords : detective quantum efficiency; linear systems theory; projection domain; image domain; x-ray imaging; detektiv kvanteffektivitet; linjär-systemteori; projektionsdomän; bilddomän; röntgenavbildning;

    Abstract : We investigate the signal and noise transform characteristics from the projection domain to the image domain in a linear systems theory framework and predictions of the DQE within this framework are made. A simulation study of a photon counting silicon detector is made from which the energy information is used in order to produce synthetic monoenergetic images. READ MORE

  3. 2. Phase-Contrast Imaging, Towards G2-less Grating Interferometry With Deep Silicon

    University essay from KTH/Fysik

    Author : Rickard Brunskog; [2022]
    Keywords : Phase-contrast imaging; phase-contrast; CT-scanning; Computed-tomography; 1 micrometer resolution x-ray; grating-less phase-contrast imaging; Faskontraströntgen; faskontrast; CT-skanning; 1 mikrometer upplösning x-ray; gitterlös faskontrast; datortomografi;

    Abstract : Conventional phase-contrast imaging entails stepping an analyser grating across the detector to resolve the interference pattern caused by the x-rays after passing through a series of gratings in a so-called Talbot-Lau interferometer. However, the analyser grating in the interferometer poses a challenge, not only due to the machinery and alignment required but also due to each exposure delivering a dose to the subject. READ MORE

  4. 3. Determination of the homogeneity of the detection efficiency of silicon detectors using light ions

    University essay from Uppsala universitet/Tillämpad kärnfysik

    Author : Hamarstedt Ellen; [2022]
    Keywords : Nuclear physics; silicon detectors; kärnfysik; kiseldetektor; kiseldetektorer;

    Abstract : In this project, the homogeneity of the detection efficiency of two silicon detectors were examined using a radioactive alpha-source, 241Am, to study the surfaces of the detectors by exposing a small part of the detector at a time. By then observing the variations of the deposited alpha-energies at different positions on the detector, one can map the differences in the homogeneity of the surface. READ MORE

  5. 4. Event-based High Resolution X-ray Imaging using Compton Coincidence Detection

    University essay from KTH/Medicinsk avbildning

    Author : Eva Bergström; [2021]
    Keywords : Photon counting CT; Compton scattering; Compton kinematics; coincidence detection; χ2 test; Fotonräknande CT; Compton-spridning; Compton-kinematik; sammanfallsdetektering; χ2 -test;

    Abstract : Research on photon counting detectors (PCDs) is focused on semiconductor materials, and silicon is a strong candidate to use in PCDs for photon counting computer tomography (CT). In a silicon detector, a significant portion of the counts is due to Compton scattering events. READ MORE

  6. 5. Simulations of silicon detector response in nuclear fission experiments : A study of the plasma delay time in an experiment performed at the Tandem lab

    University essay from Uppsala universitet/Tillämpad kärnfysik

    Author : Moa Li Lekander; Alan Aliyali; [2020]
    Keywords : Plasma delay time; silicon detector; VERDI; Tandem lab; Nuclear physics; PDT; Plasmafördröjningstid; Kiseldetektor; VERDI; Tandemlaboratoriet; Kärnfysik;

    Abstract : The goal of the project was to simulate a typical silicon detectorresponse in an experiment made at the Tandem lab in Uppsala. The plasma delay time was analyzed by simulating the experiment. Three different models of the plasma delay time were introduced and their effects on time of flight measurements were studied. READ MORE