Development of Superconducting Nb/Al Detectors

We have fabricated superconducting Nb/Al microstrip detectors. The low sensitivity to radiation damage and aging and the high energy resolution make these devices very attractive. The samples are fabricated by superposing a 2 mm x 2 mm Al area on a 5 mum wide, 100 mum long Nb strip. The thickness of each film is between 50 and 200 nm. We present the results both of steady and dynamical tests on Nb/Al bilayers, After irradiation with a Am-241 alpha-source (T=5.47 MeV). These devices can operate both in the on-off and in the auto-recovery regimes. We show that the performance of Nb/Al bilayers is better than single Nb strip devices.