Sökning: "Coincidence Measurement"

Visar resultat 1 - 5 av 15 avhandlingar innehållade orden Coincidence Measurement.

1. 1. Ultrafast Photoionization Dynamics Studied with Coincidence Momentum Imaging Spectrometers

   Författare :Yu-Chen Cheng; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Photoionization; High-order Harmonic Generation; Extreme Ultraviolet; Free-Electron Laser; Molecular Dissociation; Charge Transfer; Coincidence Measurement; Momentum Imaging; Electron Wave Packet; Fysicumarkivet A:2019:Cheng;

   Sammanfattning : The time scale of the dynamics in atoms and molecules varies from attoseconds (10-18) to picoseconds (10-12) depending on the size of the particles. To study such dynamics, ultrafast light pulses are needed to trigger and capture the reaction. One of the most direct methods consists in ionizing the system and observing the following response. LÄS MER

3. 2. The short, excited life of tellurium : Lifetime analysis of excited states in the Te midshell region

   Författare :Ebba Ahlgren Cederlöf; Ayse Nyberg; Torbjörn Bäck; Johan Nyberg; Matthias Weiszflog; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; gamma spectroscopy; lifetime measurement; lifetime; shell model; RDDS; DDCM; nuclear physics; nuclear structure; gamma spektroskopi; livstidsmätningar; livstid; skalmodellen; RDDS; DDCM; kärnfysik; kärnstruktur; Atomic; Subatomic and Astrophysics; Atomär fysik; subatomär fysik och astrofysik;

   Sammanfattning : In this licentiate thesis, lifetimes of low lying excited states in the midshell region of tellurium isotopes are discussed. The nuclear lifetimes are interesting properties to study, since they are inversely proportional to the transition probabilities, which contain information on the underlying structure of the nucleus. LÄS MER

4. 3. An Event-Reconstructing Silicon Detector for 1 µm Resolution Spectral Computed Tomography

   Författare :Christel Sundberg; Mats Danielsson; Julia Herzen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; photon-counting; silicon detector; spectral computed tomography; subpixel resolution; dose efficiency; coincidence tracking; event reconstruction; fotonräknande; kiseldetektor; spektral datortomografi; subpixelupplösning; doseffektivitet; koincidensspårning; händelserekonstruktion; Fysik; Physics;

   Sammanfattning : Computed tomography (CT) is a medical imaging modality in which cross-sectional images of the human body are created using x-rays. Commercial CT scanners utilize energy-integrating detectors to measure the x-ray attenuation. However, photon-counting detectors with energy-discriminating abilities have started to emerge. LÄS MER

5. 4. Short Attosecond Pulse Trains at High Repetition Rates for Novel Pump-Probe and Coincidence Studies

   Författare :Sara Mikaelsson; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Attosecond; High-Order Harmonic Generation; Photoionization; Attosecond; High-Order Harmonic Generation; Photoionization; Fysicumarkivet A:2021:Mikaelsson;

   Sammanfattning : This work aims at studying photoionization dynamics from atoms and surfaces at attose time scales. The work was based on development and applications of a high repetition rate High-order Harmonic Generation (HHG) light source that utilizes Optical Parametric Amplification (OPA) laser technology. LÄS MER

7. 5. Charge and proton dynamics in molecules and free clusters : from atomic to nanometer scale

   Författare :Bart Oostenrijk; Synkrotronljusfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Charge transfer; Electron-Ion coincidence; proton hopping; Coulomb explosion; Cluster fission; site-selective dissociation; Molecular photodissociation; spectroscopy; Fysicumarkivet A:2018:Oostenrijk;

   Sammanfattning : The origin of properties in complex systems can often be traced to mechanisms involving charge and energy transfer in only a few embedded molecules. The detailed study of the time evolution of these mechanisms in their original environment is a challenging task. LÄS MER