<title>X-ray detection with an Nb-based junction and investigation of series-junction detectors</title>

Abstract

Two topics on our recent investigations into superconducting tunnel junction (STJ) detectors are discussed: the single Nb/A1.AlOx/Al/Nb junction for high-resolution x-ray detection and the series-connected superconducting tunnel junction detectors (SCSDs) with high detection efficiency. Using a single Nb/AlAlOx/Al/Nb junction with rather large area of 178 x 178 2, we obtained a high energy resolution of 88 eV for 5.9-keY x-rays. The signal-to-noise ratio of the SCSD is discussed from a simple theoretical formulation of electronics, showing that the series-connected STJs can developed as a nuclear radiation detector both with high energy resolution and high efficiency. Recent experimental results of our SCSD are also given in this paper.