A superconducting tunnel junction was bombarded with alpha particles and the resulting pulses in the quasiparticle tunneling current were observed. The possibility of utilizing this effect in nuclear spectrometry is discussed.

A superconducting thin film tunnel junction (Sn–SnO2–Sn) of total thickness 400 nm, area 7 × 10−4 cm2, and normal (4.2 K) resistance 77 m? was prepared on a glass substrate. When cooled to 1.2 K and suitably electrically and magnetically biased, the junction was bombarded with 5.1 MeV alpha particles. The resulting pulses induced in the tunnel current were observed to have amplitudes up to 19 times the r.m.s. output noise level. The possibility of utilizing this effect in charged particle spectrometry is explored.

CRYSTMET is a computer-readable database of critically evaluated crystallographic data for metals (including alloys, intermetallics and minerals) accompanied by pertinent chemical, physical and bibliographic information. It currently contains about 60 000 entries and covers the literature exhaustively from 1913. Scientific editing of the abstracted entries, consisting of numerous automated and manual checks, is done to ensure consistency with related, previously published studies, to assign structure types where necessary and to help guarantee the accuracy of the data and related information. Analyses of the entries and their distribution across key journals as a function of time show interesting trends in the complexity of the compounds studied as well as in the elements they contain. Two applications of CRYSTMET are the identification of unknowns and the prediction of properties of materials. CRYSTMET is available either online or via license of a private copy from the Canadian Scientific Numeric Database Service (CAN/SND). The indexed online search and analysis system is easy and economical to use yet fast and powerful. Development of a new system is under way combining the capabilities of ORACLE with the flexibility of a modern interface based on the Netscape browsing tool.

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