Time resolved studies of scintillation materials with VUV harmonic ultrashort pulse laser source

High energy excitation, after a very fast electron-electron diffusion cascade, leads to the creation of excited region with many electrons and holes of typical energies from few to several tens of electron-volts. At this stage, the scintillation process involves the same electronic relaxation and energy transfer mechanisms as those occurring under VUV excitation. Time-resolved luminescence spectroscopy with VUV and X-synchrotron radiation became today a principal investigation method of energy relaxation mechanisms in scintillation materials. High-order harmonic (HH) generation is a very promising new XUV source for these studies. The emission of HH occurring when an intense linearly polarized femtosecond laser pulse interacts with an atomic gas. We present the results of characterization of HH source mounted at C.E.L.I.A. laser (20 mJ, 20 fs, 1 kHz). The experimental setup giving the possibilities of many applications in physics and chemical-physics as well as a first time-resolved luminescence measurements of scintillation materials are described. The main advantages of harmonic radiation for spectroscopic study are: quasi continuous spectrum in the VUV region (10-100 eV), ultra-short pulse (ps and sub-ps), high pulse intensity (up to 106 photons/pulse/eV), relatively high frequency of pulses (1 kHz) and table-top size.