Consider a photoelectron spectroscopy setup with the following definition of geometry z Electron detector hy e Crystal The angle A describes how far the detector is off-normal (@= () is normal to the sample) The angle o describes the azimuthal angle of the detector with respect to the photons incoming angle. Depending on the type of sample and sample surface the following statements can be made: When measuring core levels by XPS increasing & will When measuring core levels by XPS changing o will When measuring the valence band of a two dimensional surface structure with UPS increasing & will When measuring the valence band of a two dimensional surface structure with UPS changing o will Consider a photoelectron spectroscopy setup with the following definition of geometry z Electron detector hy e Crystal The angle A describes how far the detector is off-normal (@= () is normal to the sample) The angle o describes the azimuthal angle of the detector with respect to the photons incoming angle. Depending on the type of sample and sample surface the following statements can be made: When measuring core levels by XPS increasing & will When measuring core levels by XPS changing o will When measuring the valence band of a two dimensional surface structure with UPS increasing & will When measuring the valence band of a two dimensional surface structure with UPS changing o will