Superconducting Tunnel Junctions for High-Energy-Resolution X-Ray Detectors

Compact, high energy resolution X-ray detectors are required for spaced based X-ray astronomy. Superconducting tunnel junction (STJ) X-ray sensors, based on the collection of quasiparticles produced by the absorption of X-ray photons, will allow the construction of X-ray spectrometers with better than an order of magnitude improvement in energy resolution over state of the art semiconducting PIN devices, at a small fraction of the weight of conventional systems. The development of these detectors represents an innovation in X-ray detectors because of their light weight and high energy resolution, making them ideal for use on spaced based platforms. Furthermore, thin film STJ X-ray detectors will have important commercial applications in X-ray spectrometers on electron microprobe instruments, for elemental compositional analysis of specimens through energy dispersive X-ray methods. The objective of our research is the construction of STJ detectors with an energy resolution in excess of 10 eV, for application in X-ray spectroscopy.