Abstract
The Sn-SnOx-Sn tunnel junction of a crossed-film type, cooled down to 0.32 K, is demonstrated as a good energy resolution detector for α particles. Three junctions (A, B: 300×400 μm2×3000 Å and C: 200×300 μm2×3000 Å) have been used to detect 5.3-MeV α particles from 210Po. The present work suggests that reduction of the leakage current enables us to utilize superconducting tunnel junctions with large volumes. Such a device could provide a new means for detection of unclear radiations.