Project Title:

Superconducting Tunnel Junctions with Multilayer Electrodes as

Conductus, Inc.
969 W. Maude Ave.
Sunnyvale, CA 9408-2802

93-1		08.14	6700	B		Amount Requested $69,500.87

Superconducting Tunnel Junctions with Multilayer Electrodes as 
Energy-Resolving X-ray Detectors

Abstract:

Superconducting tunnel junction X-ray spectrometers promise to 
combine efficiency and broad bandwidth with high-energy 
resolution--a combination not available in current commercial 
detectors.  Conductus, Inc., in collaboration with Lawrence 
Livermore National Laboratory, has begun development of STJ X-ray 
detectors which use a novel multilayer electrode structure.  We 
have already demonstrated Nb/Al-Al2O3-Al/Nb tunnel junction 
detectors with about 40 eV resolution for 6 keV X-rays; this is the 
best resolution ever obtained for any type of STJ detector.  
Because of their simplicity, bandwidth, resolution and count-rate 
capability, superconducting tunnel junction spectrometers should be 
ideally suited for X-ray astronomy applications.
In phase I of this project we will optimize the electrode structure 
for energy resolution and operating temperature.  In phase II we 
will develop large area detector arrays with high quantum 
efficiency and high spatial resolution.

An energy-resolving X-ray detector which has high resolution, broad 
bandwidth, and high efficiency would be extremely useful for a wide 
range of applications.  Not only would such a device be uniquely 
suited for X-ray astronomy, it would also find application in: 
microprobe analysis, X-ray fluorescence spectrometry, non-
destructive testing, X-ray microscopy, radiation damage studies, 
measuring cross sections of highly ionized elements, and as a 
particle detector with a low-energy threshold.

X-ray astronomy, X-ray detector, tunnel junction