Luminescent properties of composite scintillators based on PPO and o-POPOP doped SiO2 xerogel matrices

New composite scintillation detectors were obtained by incorporation of PPO and o-POPOP organic scintillators into porous sol-gel silica matrices. Composites possess high photoluminescence intensity and decay time in nanosecond range. The absolute light yield of composite scintillators at excitation by alpha-radiation is about 4000-5000 photons/MeV and the pulse-height resolution is about 30%. The investigations of time-resolved luminescence of composites performed under excitation by synchrotron radiation in the 3.7-25 eV range have shown that the non-radiative energy transfer between host matrix and dopant molecules occurs via singlet states of SiO2 oxygen-deficient centers.