UBC Theses and Dissertations
Investigation of planar arrays of superheated superconducting spheres Meagher, Gail Aileen
The Planar Array of Superheated Spheres (PASS) has been put forward as a possible neutrino and dark matter detector. This work has concentrated on the characteristics of a 100x100 array of spheres, of indium or tin. The superheated-supercooled hysteresis curves, for magnetic fields ranging from the earth's to 16 mT, have been measured in a pumped ⁴He cryostat using an RF-SQUID readout system. Individual superconducting to normal grain flips were recorded with the indium sample due to exposure to 60 keV gammas. The effect of gravity on the shape and structure of the spheres was tested by remelting arrays in a microgravity environment. The hysteresis curves obtained for these arrays showed a decreased transition width, i.e. the temperature difference from where all the spheres are superconducting to where they are all normal.
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