Development of a dark matter detector using series arrays of superconducting tunnel junctions

We are developing a dark matter detector for Weakly Interacting Massive Particles (WIMPs) using Series Arrays of Superconducting Tunnel Junctions (SASTJs) to read out phonon signals from absorber crystals. We discuss the factors which have determined the choice of our detector scheme. As an improvement over previously produced SASTJs using a shadow mask technique, a new fabrication process of high-quality Al/Al-oxide/Al junctions and SASTJs is being developed using photolithography to define the structures. The processing and the electrical characterisation of the first devices produced in this way are described.