SIGNAL-TO-NOISE RATIO OF SUPERCONDUCTING TUNNEL JUNCTION DETECTORS

The optimal signal to noise ratio for detectors based on superconducting tunnel junctions (STJ) is compared for the cases of a detector consisting of one single STJ, as well as of series and of parallel connections of STJs. A single STJ exhibits the best signal to noise ratio if the signal charge is independent of detector area. If signal charge increases in proprotion to the detector area, a parallel or a series connection of STJs would provide the optimum signal to noise ratio. The signal to noise ratio is deduced as function of junction parameters.