Energy relaxation in scintillators

Specific information, which can be obtained for scintillators by their study using luminescence spectroscopy in the VUV and XUV range, is reviewed. Special emphasis is made on the light yield and nonproportionality of the response. While the former is closely related to the types of electronic excitations their mutual transformations and multiplicity of relaxation pathways, the latter one is to a large extend controlled by the spatial distribution of hot and thermalized excitations. In the VUV region the dependence of the luminescence yield on the energies of electrons and holes can be studied which is required for the simulation of relaxation cascades. The onset of processes resulting in the creation of secondary excitations also falls into the VUV region, thus their energy dependence can be obtained. In the XUV region core hole Auger cascades resulting in the creation of `clusters´ of excitations set in and thus density effects can be studied. Within this approach a number of modern scintillators has been studied using synchrotron radiation, examples are presented