Josephson tunnel junctions as fast nuclear particle position detectors

We present here some problems and solutions in using Josephson junctions as fast nuclear particle position detectors. The process of induced switching is modelled in terms of a reduction of the critical current due to a disturbed volume: the hotspot. The spurious thermal induced switching process is also taken into account. Calculations in order to choose the junction parameters are presented. The all refractory junctions fabrication technology developed is capable of satisfying design prescriptions.