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A&A Supplement series, Vol. 127, February I 1998, 497-504

Received March 20; accepted June 11, 1997

Recent developments in superconducting tunnel junctions for ultraviolet, optical & near infrared astronomy

T. Peacock, P. Verhoeve, N. Rando, C. Erd, M. Bavdaz, B.G. Taylor, and D. Perez

Astrophysics Division, Space Science Department of the European Space Agency, ESTEC, PO Box 299,2200 AG Noordwijk, The Netherlands


Some recent results associated with the development of tantalum based photon counting superconducting tunnel junctions (STJ) suitable for use as broad-band low resolution spectrometers for optical and ultraviolet astronomy are presented. A tex2html_wrap_inline1020m square tantalum based STJ, operated at a temperature of 0.3 K, has demonstrated a limiting resolution of tex2html_wrap_inline1022 nm at 200 nm and tex2html_wrap_inline1024 nm at 1000 nm. The device is extremely linear in response with photon energy, and covers the waveband from 200 nm to tex2html_wrap_inline1026 while measuring the individual photon wavelength and arrival time. The short wavelength limit is currently constrained by the current experimental configuration (a fibre optic) as well as to some extent the sapphire substrate. The estimated quantum efficiency for single photons is over tex2html_wrap_inline1028 between 200 and 700 nm with a maximum of tex2html_wrap_inline1030 at 550 nm. Such an STJ when packaged into an array could contribute significantly to many fields of near infrared, optical and ultraviolet astronomy being able to provide efficiently and simultaneously the broad band spectrum and photon arrival time history of every single object in the field over a very wide dynamic range.

keywords: instrumentation: detectors -- photometry -- superconductors -- tunnel junctions -- optical/ultraviolet spectroscopy

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