Operation of Nb/Al superconducting microstrips as radiation detectors

We have developed superconducting Nb/Al microstrip detectors. These devices appear to be very attractive due to their low sensitivity to radiation damage and aging, and to their high energy resolution. 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 of both steady and dynamical tests on Nb/Al bilayers, after irradiation with a Am-241 alpha-source. We show that the performance of Nb/Al bilayers is better than that of single Nb strip devices.