Further Work with Noble Element Scintillators

An investigation of the relative scintillation efficiencies of the various noble gas mixtures has been made in an attempt to find a combination that would yield either more light than any of the pure gases or allow a more economical use of the heavier gases without substantial loss of light. Data on the efficiency of all binary mixtures of Xe, Kr, A, Ne, and He are presented. They show a characteristic large drop in the light for mixtures containing a small proportion of the heavier gas in a major fraction of the lighter. However, a 10 per cent Xe-90 per cent He mixture has a relatively large output and could be useful in constructing a high-efficiency neutron counter using the He3(n, p)H3 reaction. Data are also presented on the relative conversion efficiencies of several commonly used organic waveshifters. Of those tested, the best are diphenyl stilbene, tetraphenylbutadiene, and quaterphenyl having relative efficiencies of 1.0, 0.7, and 0.4, respectively. A survey investigation was also made of the relative efficiencies of solid and liquid xenon, krypton, and argon for ordinary glass and for quartzfaced photomultipliers. Although these data are not as accurate or reproducible as the corresponding work on gases, they indicate several of the combinations may approach NaI(T1) in light output.