Suppression of extrinsic resolution limiting factors in epitaxial superconducting tunnel junction detectors

Author

Porter, F.S. ; Van Vechten, D. ; Blamire, M.G. ; Kirk, E.C.G.

Author_Institution

Naval Res. Lab., Washington, DC, USA

Volume

5

Issue

2

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

3026

Lastpage

3029

Abstract

Superconducting tunnel junctions have been shown to have potential as high resolution X-ray detectors. Recent reductions in the noise environment of our experiment have yielded a substantial increase in the resolution of our Nb/Ta junctions. The junctions used in the experiment are epitaxial base layer devices including a thick Ta absorber and have survived more than 30 cycles to low temperatures. Current experiments with a /sup 55/Fe source have yielded an energy resolution of 68 eV at 5.89 keV with a quantum efficiency of 13%. Additional measurements using a higher energy /sup 109/Cd source are also reported. We discuss how a reduction of extrinsic and quasi-extrinsic noise sources affects the performance of the detectors and why we believe we are still not observing the intrinsic limitations of these junctions.<>

Keywords

X-ray detection; niobium; superconducting device noise; superconducting epitaxial layers; superconducting particle detectors; tantalum; /sup 109/Cd source; /sup 55/Fe source; 13 percent; 5.89 keV; Nb-Ta; Nb/Ta junctions; Ta absorber; X-ray detectors; energy resolution; epitaxial base layer devices; noise; quantum efficiency; superconducting tunnel junctions; Energy resolution; Josephson junctions; Niobium; Noise reduction; Semiconductor counters; Superconducting device noise; Superconducting epitaxial layers; Temperature; Working environment noise; X-ray detectors;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.403229

Filename

403229