Towards An Imaging Soft X-ray Spectrometer Based On Superconducting Tunnel Junction Detectors

摘要

We describe the next generation of our Distributed Read-Out Imaging X-ray Detectors based on superconducting tunnel junctions (STJs). Various shapes of the readout STJs and sizes of absorbers are compared with a view to optimizing the sensitive area and fill factor of future arrays while maintaining good energy resolution. Also different absorber configurations will be explored: the traditional integrated absorber is compared with an absorber deposited after definition of the read-out structures. In support of this work, the feasibility of Re as an absorber is demonstrated with the detection of single UV photons in a Re/Al STJ. In addition, our tunnel barriers have successfully been made more transparent without loss of their low leakage properties. Finally, Nb contacts which prevent quasiparticles from escaping the STJs are identified as a source of device to device variability in the performance.