SCINTILLATOR BASED ON SIO2-AEROGEL

For increasing the light output of SiO2-aerogel two aerogel samples we re doped with the wavelength shifter POPOP. As a result a scintillator with intermediate density between the gas and the solid state has bee n produced. The light pulse shapes of the both samples are well approx imated by a sum of two exponents with the decay times 1.4 +/- 0.1 ns ( 58% of total light output) and 5.2 +/- 0.4 ns (42%). Under irradiation of 5.5 MeV alpha-particles the light output of the sample with smalle r wavelength shifter concentration was 30% and that of the sample with larger concentration was 8% of the light output of a plastic scintill ator (polysterene, 2% paraterphenil, 0.2% POPOP). The obtained data in dicate that the alpha/beta ratio for both samples is close to 1. This material can be used in experiments where the amount of substance in t he way of particles to be detected is a critical factor.