Development of High Throughput X-ray detectors using Superconducting Tunnel Junctions with a large area size

We have developed 100-pixel Nb/Al based superconducting tunnel junction (STJ) array detectors which was enlarged the pixel size to improve X-rays detection throughput. The two different sizes of 100 μm × 100 μm and 160 μm × 160 μm STJs which consisting of Nb (100 nm)/Al (70 nm)- AlO_X/Al (70 nm)/Nb (300 nm) were fabricated to determine the effective size of a single STJ. The leakage current, the fabrication yield and the energy resolution for Al- K _α of 100 μm-square and 160 μm-square STJs were 9.3 ± 4.6 nA and 12.3 ± 9.7 nA, 85 % and 84 %, 23.6 ± 4.6 eV and 27.5 ± 3.8 eV, respectively. Since these exhibited almost equal performance, it is found that STJs with a size of 160 μm × 160 μm can be used as a high throughput X-ray detector. (paper)