X-ray detection by superconducting tunnel junctions via phonon propagation in the substrate
Publication date: 02 April 1996
Authors: Poelaert, A., et al.
Journal: Journal of Applied Physics
Volume: 79
Issue: 9
Page: 7362-7369
Year: 1996
Copyright: American Institute of Physics
The x-ray performance of Nb-Al-AlOx-Al-Nb superconducting tunnel junctions deposited on sapphire has been studied for phonon mediated detection of x rays absorbed in the substrate in the energy range 750 to 6000 eV. Two separate channels of phonon propagation can be identified. One produces a discrete signal peak, due to high frequency phonons originating from the x-ray absorption sites in a shallow layer below the junction. The other contributes to a monotonic signal tail, due to low frequency phonons, reaching the junction after diffusive or multiple scattering at surfaces.
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