Ta-based tunnel junctions for energy resolving X-ray detection

Author

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

Author_Institution

Dept. of Mater. Sci., Cambridge Univ., UK

Volume

5

Issue

2

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

3014

Lastpage

3017

Abstract

We report the results of a programme to develop an energy-resolving superconducting tunnel junction based on a Ta X-ray absorber. The design is based on a vertical heterostructure consisting of a Nb underlayer to act as a quasiparticle reflector, a thick Ta absorber layer and an Al trap layer. The upper surface of this trap layer is oxidised to form the tunnel barrier. The counterelectrode consists of an Al and thin Nb layer with thicknesses controlled to give approximately equal energy gaps in both electrodes and minimal absorption in the Nb counterelectrode. The effect of electro-magnetic barrier resonances on detection performance has been evaluated. Very high quality junctions have been fabricated, tested and evaluated for X-ray energy resolution.<>

Keywords

X-ray detection; superconducting particle detectors; tantalum; Al trap layer; Nb counterelectrode; Nb quasiparticle reflector; Nb-Ta-Al-AlO-Al-Nb; Ta X-ray absorber; X-ray detection; electro-magnetic barrier resonances; energy gaps; energy resolution; superconducting tunnel junction; vertical heterostructure; Electrodes; Electromagnetic wave absorption; Energy resolution; Josephson junctions; Niobium; Resonance; Superconducting epitaxial layers; Testing; Thickness control; X-ray detection;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.403226

Filename

403226