Sökning: "electron beams"
Visar resultat 1 - 5 av 91 avhandlingar innehållade orden electron beams.
1. Clinical application of intensity and energy modulated radiotherapy with photon and electron beams
Sammanfattning : In modern, advanced radiotherapy (e.g. intensity modulated photon radiotherapy, IMXT) the delivery time for each fraction becomes prolonged to 10-20 minutes compared with the conventional, commonly 2-5 minutes. The biological effect of this prolongation is not fully known. LÄS MER
2. Studies on high brightness electron beams for short pulses and free electron laser
Sammanfattning : Accelerator based lightsources are one of the most powerful tools today for producing high intensity radiation at very short wavelengths. While synchrotron storage rings provide a high average brilliance in a wide wavelength range, the next generation of lightsources aim towards producing ultra-short pulses in the X-ray regime. LÄS MER
3. Theoretical and Computational Studies on the Physics of Applied Magnetism : Magnetocrystalline Anisotropy of Transition Metal Magnets and Magnetic Effects in Elastic Electron Scattering
Sammanfattning : In this thesis, two selected topics in magnetism are studied using theoretical modelling and computational methods. The first of these is the magnetocrystalline anisotropy energy (MAE) of transition metal based magnets. In particular, ways of finding 3d transition metal based materials with large MAE are considered. LÄS MER
4. Electron energization in near-Earth space : Studies of kinetic scales using multi-spacecraft data
Sammanfattning : Plasma, a gas of charged particles exhibiting collective behavior, is everywhere in the Universe. The heating of plasma to millions of degrees and acceleration of charged particles to very high energies has been observed in many astrophysical environments. How and where the heating and acceleration occur is in many cases unclear. LÄS MER
5. Electron Heating and Acceleration at Earth’s Collisionless Bow Shock
Sammanfattning : Cosmic rays are ultra-relativistic particles traveling near the speed of light permeating the galaxy. Collisionless shock waves with their ubiquity throughout the universe and excellent capability of accelerating charged particles offer an explanation to the origin of cosmic rays. LÄS MER